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Dietary options for the sauropod dinosaurs from an integrated botanical and paleobotanical perspective

January 2011

In book: Biology of the Sauropod Dinosaurs: Understanding the Life of Giants (pp.34-56)
Chapter: 3
Publisher: Indiana University Press
Editors: N. Klein, K. Remes, C.T. Gee, P.M. Sander

Authors:

University of Bonn

during the majority of the Mesozoic, from the Tri-assic to the mid Cretaceous, the food plants of the sauro-pod dinosaurs were virtually limited to ferns, fern allies, and gymnosperms because the diversification of the an-giosperms, which include the broad-leaved trees and grasses of today, only began in the Late Cretaceous. In this chapter, the preferences of the sauropods for one or more of these Mesozoic plant groups are evaluated by means of a survey approach that integrates botanical and paleobotanical data. These data include the growth hab-its of the nearest living relatives of these plant groups, their habitat, the amount of biomass produced, and the ability to regrow shoots, branches, and leaves after injury through herbivory. The relative quantities of energy and essential nutrients yielded to herbivores with hindgut fermentation, the consumption of the various plant groups by modern herbivores, and the coeval occurrence of sauropods and individual plant groups in the fossil record are other major factors taken into consideration here. As a result of this extensive survey, it appears that Araucaria, Equisetum, the Cheirolepidiaceae (an extinct conifer family), and Ginkgo would have been most acces-sible, sustaining, and/or preferred sources of food for the sauropods. Moderately accessible, sustaining, and/or commonly encountered plants would have been other conifers such as the Podocarpaceae, Cupressaceae, and Pinaceae. Less commonly browsed by the sauropods, es-pecially by large, fully grown individuals, would have been forest-dwelling ferns such as Angiopteris and Os-munda. The least frequently eaten plants were probably the cycads and bennettitaleans.

Paleogeographic map of the Late Jurassic (Kimmeridgian). Shown in black are the approximate locations of the three major sauropod faunas discussed in this chapter. (1) Morrison Formation, Western Interior of North America. (2) Patagonia, southern South America. (3) Tendaguru, Tanzania, Africa. Light gray indicates land; medium gray, highlands; and white areas within the black lines, flooded shelves. Map modified after Smith et al. (2004).

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.1. Likeliness of Mesozoic Plant Groups as a Preferred Food Source for the Sauropod Dinosaurs

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Dietary Options for the Sauropod Dinosaurs from an

Integrated Botanical and Paleobotanical Perspective

CAROLE T. GEE

during the majority of the Mesozoic, from the Tri-

assic to the mid Cretaceous, the food plants of the sauro-

pod dinosaurs were virtually limited to ferns, fern allies,

and gymnosperms because the diversiﬁcation of the an-

giosperms, which include the broad-leaved trees and

grasses of today, only began in the Late Cretaceous. In

this chapter, the preferences of the sauropods for one or

more of these Mesozoic plant groups are evaluated by

means of a survey approach that integrates botanical and

paleobotanical data. These data include the growth hab-

its of the nearest living relatives of these plant groups,

their habitat, the amount of biomass produced, and the

ability to regrow shoots, branches, and leaves after injury

through herbivory. The relative quantities of energy and

essential nutrients yielded to herbivores with hindgut

fermentation, the consumption of the various plant

groups by modern herbivores, and the coeval occurrence

of sauropods and individual plant groups in the fossil

record are other major factors taken into consideration

here. As a result of this extensive survey, it appears that

Araucaria, Equisetum, the Cheirolepidiaceae (an extinct

conifer family), and Ginkgo would have been most acces-

sible, sustaining, and/or preferred sources of food for the

sauropods. Moderately accessible, sustaining, and/or

commonly encountered plants would have been other

conifers such as the Podocarpaceae, Cupressaceae, and

Pinaceae. Less commonly browsed by the sauropods, es-

pecially by large, fully grown individuals, would have

been forest-dwelling ferns such as Angiopteris and Os-

munda. The least frequently eaten plants were probably

the cycads and bennettitaleans.

Introduction

Botanically, it seems that the thick-cuticle conifers, toxic

cycads, and low-biomass ferns would have offered little in

terms of palatable, sustaining fodder to the early and mid

Mesozoic sauropods, yet we know that giant sauropods did

exist and must have thrived on these plant groups. Indeed,

ferns and gymnosperms dominated the ﬂora during the better

part of the Mesozoic, speciﬁcally, some 140 million years al-

together. The great diversiﬁcation of the ﬂowering plants, and

hence the onset of the modern ﬂora, took place in the mid

Cretaceous, after about four ﬁfths of the Mesozoic had already

passed by. Angiosperms, the producers of broad leaves, ﬂowers,

and fruits in the present-day world, thus fed the herbivorous

dinosaurs for only a relatively short span of time.

The plant groups that greened the Earth from the Early Trias-

sic (251 million years ago) to the mid Cretaceous (100 million

years ago) included ferns and fern allies, cycads and bennet-

titaleans, seed ferns, ginkgophytes, and conifers. Like the dino-

saurs, some of these taxa—major groups such as the bennet-

titaleans, seed ferns, and the cheirolepidiaceans— went extinct

at the end of the Mesozoic, but others have survived to this day.

Dietary Options for the Sauropod Dinosaurs 35

Indeed, a few plants that have remained unchanged at the

genus level since the Mesozoic, for example, the horsetail Equi-

setum, the tropical ferns Angiopteris and Marattia, the maiden-

hair tree Ginkgo, and the southern conifer Araucaria. The living

species of these genera can be looked on as the embodiment of

close relatives that nourished the dinosaurs.

Although it is clear that herbivorous dinosaurs must have

fed on and attained gigantic sizes using nonangiospermous

plants, it is less obvious which of these plants—if any—they

might have preferred as a food source. Were some plant

groups more nutritious than others? Did the dinosaurs prefer-

entially live (and feed) in certain kinds of vegetation? Further-

more, after a herd of dinosaurs or perhaps just a particularly

hungry individual had decimated an area of its ﬂora, were

some plants better able to recover and regenerate their foliage

than others, thus surviving another season to grow, repro-

duce, and possibly withstand another onslaught of herbivory?

This chapter tackles the question of dietary options for the

herbivorous dinosaurs, focusing on sauropods, by conducting

a survey of the preangiospermous Mesozoic ﬂora, especially

in light of any nearest living relatives, to see how suitably

they would have served as dinosaur fodder in regard to their

growth habit, the habitat in which they grew, the amount of

biomass they were able to produce, their ability to regrow

shoots, branches, and leaves, and the quantity of energy and

important nutrients they would have offered herbivores. Al-

though these nonangiospermous plant groups are not usually

considered forage plants for modern plant eaters, reports

of consumption involving living animals are noted here

as well.

In addition to analyzing living plants, the fossil record can

be gleaned for clues to the food preferences of the sauropod

dinosaurs. For example, the coeval occurrence of both sauro-

pods and speciﬁc plant groups at the same fossil localities in-

creases the possibility that these dinosaurs fed on these plants,

assuming that these death assemblages represent the living

biota to a reasonable extent.

Finally, on the basis of data from living plants, extant her-

bivores, and the fossil record, each Mesozoic plant group is

rated comparatively for its likelihood as a food option for the

sauropod dinosaurs.

PREVIOUS APPROACHES

A number of approaches have been developed to try to ﬁnd

out what sorts of plants herbivorous dinosaurs preferred feed-

ing on. These include using trace fossils, dinosaur morphol-

ogy, and plant factors such as morphology and physiology.

Trace Fossils

The most direct approach would seem to be the study

of plant remains in dinosaur coprolites or digestive-tract re-

mains. Yet this approach is not as straightforward as generally

assumed for several reasons, which were recently discussed in

great detail (Sander et al. 2010). In regard to coprolites, it is

difﬁcult to positively and unequivocally trace fossilized fecal

material to a particular genus or even type of plant-eating

dinosaur. Even in the case of the putative sauropod coprolites

found in the same horizon as titanosaurs in the Upper Creta-

ceous Lameta Formation of India, there is some doubt that

such gigantic animals would have produced such small co-

prolites (Sander et al. 2010). Furthermore, it is questionable

whether the ‘‘soft’’ plant tissues, especially of fern fronds, re-

ported from these nodule-shaped structures (Mohabey 2005)

would have survived the three to four days of chemical and

mechanical processing in a large herbivore’s digestive system

(cf. Hummel & Clauss, this volume).

In the case of stomach remains and other reports of digestive-

tract remains, even if fossilized plant material is found inside a

dinosaur’s body cavity, it is still unclear whether this material

truly represents the digestive remains or a postmortem ac-

cumulation. In one well studied case of a mummiﬁed hadro-

saur, the highly diverse pollen ﬂora in the plant material, cou-

pled with the uniform particle size of the plant megafossils,

plus the occurrence of an unusual mixture of charcoal, dino-

cysts, and other algae, led researchers to suggest that these

plant remains were washed into the body after death (Currie

et al. 1995).

Indeed, in a critical look at coprolite and digestive-tract re-

mains in herbivorous dinosaurs, Sander et al. (2010a) reported

that most cases are problematic in their authenticity, with the

exception of one well documented specimen of an apparently

frugivorous bird, Jeholornis prima from the Lower Cretaceous

of China (Zhou & Zhang 2002), with seeds in its gut, and of

another case consisting of clusters of pellet-like coprolites

with bennettitalean leaf cuticle from an English dinosaur (Hill

1976). It should be noted that in both of these instances, the

plant remains were monotypic in regard to plant parts (i.e.,

seeds or leaves) and generally monospeciﬁc in regard to plant

taxon (i.e., Carpolithes or bennettitaleans). This would be in

line with a feeding behavior in which the animal feeds on only

one type of plant part of a single species, depending on what is

ripe or available at the time. Thus, such cases would depict the

last meal eaten by the dinosaur immediately before death and

burial, and would be less likely to represent the spectrum of

the animal’s overall diet.

Dinosaur Morphology

Other approaches to deciphering herbivorous dinosaur

feeding habits involve the analysis of teeth, jaw mechanics,

skull shape, neck length, and other food-processing structures

such as gastric mills. Because this topic has also been subject to

a recent critical discussion (e.g., Sander et al. 2010a; Hummel

& Clauss, this volume), it will be not repeated here. However,

gee

it should be noted that it is thought that the success of

the sauropod dinosaurs in regard to gigantism was based

in part on the fact that they did not chew, which enabled

them to ingest large mouthfuls of food rapidly and continu-

ously (Sander & Clauss 2008; Sander et al. 2010b; Hummel &

Clauss, this volume). Other probable factors included egg lay-

ing, a high growth rate, avian-style respiration, an ontoge-

netically ﬂexible metabolic rate, and a long neck (Sander &

Clauss 2008; Sander et al. 2010a, 2010b; Griebeler & Werner,

this volume; Sander et al., this volume).

Plant Factors

The giant body size of sauropods, along with their need

to consume huge amounts of plant material for growth and

maintenance, necessarily means that they were bulk feeders.

As revealed by the cropping efﬁciency experiments on conifer

and angiosperm twigs carried out by Hummel & Clauss (this

volume, and references therein), sauropods would have been

most efﬁcient when foraging on conifers, and not on angio-

sperms (i.e., broad-leaved trees) or ferns because they would

have received more biomass with each bite of conifer foliage.

Qualitatively, there are also differences in energy and nu-

trient yield between different plant groups. Although it had

been assumed for many years that the preangiosperm Meso-

zoic plants could have provided only low-quality fodder for

herbivorous dinosaurs (Coe et al. 1987; Taggart & Cross 1997;

Tiffney 1997; Midgley et al. 2002), recent empirical laboratory

experiments estimating the amount of energy yielded by the

nearest living relatives of the Mesozoic ﬂora (Hummel et al.

2008; Sander et al. 2010a; Hummel & Clauss, this volume)

have shown that a number of ferns, conifers, and other gym-

nosperms actually offer herbivores relatively large amounts of

energy, comparable to or even surpassing grasses or broad-

leaved trees (see Hummel & Clauss, this volume). These high-

energy plants include horsetails such as Equisetum, ferns such

as Osmunda and Angiopteris, conifers such as Araucaria, Tor-

reya, Taxus, and Cephalotaxus, and the maidenhair tree Ginkgo.

Conversely, there are other plants, namely the cycads and

podocarps, that prove to be poor sources of energy. These new

perspectives reveal another factor that can be used in the eval-

uation of the various Mesozoic plant groups for their potential

as sauropod fodder and are incorporated here into the botani-

cal and paleobotanical data on each plant group.

Parameters Considered

CHRONOSTRATIGRAPHY AND PALEOGEOGRAPHY

To control for ﬂoral and faunal differences dependent on geo-

logical time, this chapter focuses on the Late Jurassic sites or

regions that have produced well documented sauropod fau-

nas and Mesozoic ﬂoras. Speciﬁcally, this encompasses the

Morrison Formation of the Western Interior of North Amer-

ica, the Patagonian region of southern South America, and the

Tendaguru Beds in Tanzania, East Africa (Fig. 3.1).

FERMENTATION VALUES

Because the fermentation curves of Hummel et al. (2008) are

reproduced in another chapter (Hummel & Clauss, this vol-

ume; see also Sander et al. 2010b), they will not be duplicated

here. However, I propose here a ﬁve-point scale categorizing

the amounts of gas production in order to describe qualita-

tively the relative amount of energy released from each food

plant type during the 72 hour long fermentation trials of

Hummel et al. (2008) and to facilitate comparison between

plant groups. Hence, excellent is over 45 ml/200 mg dry mat-

ter; very good is 35–45 ml/200 mg dry matter; good is 25–35

ml/200 mg dry matter; poor is 15–25 ml/200 mg dry matter;

and very poor is under 15 ml/200 mg dry matter.

Analysis of Plant Taxa

ARAUCARIACEAE

Habit and Habitat

The family Araucariaceae is represented today by three

genera—Araucaria (Plate 3.1), Agathis, and Wollemia—all of

which form tall evergreen trees. On average, the 20 or so spe-

cies of Araucaria reach heights of about 30 m, but A. hetero-

phylla, which is commonly grown in northern temperate re-

gions as a garden or house plant (i.e., the Norfolk Island pine),

can top out at 70 m (Krüssmann 1972). Mature trees of Arau-

caria (Plate 3.1F) or Agathis often occur singly as canopy domi-

nants in the forest, although Araucaria can also make up rela-

tively dense, monospeciﬁc groves of trees (Schütt et al. 2004).

All three genera occur in tropical and subtropical forests.

While Araucaria is native to both South America and Austra-

lasia, Agathis is widespread in Australasia (Krüssmann 1972),

and Wollemia is restricted to a single rain forest gorge near

Sydney, Australia (Jones et al. 1995).

Biomass Production

Like present-day members of the family, fossil Araucariaceae

formed tall trees, and their spreading branches probably con-

stituted quite a bit of biomass. In the past, as in the present,

these trees were likely slow growers; Araucaria plantations

in Northern Queensland, for example, take twice as long to

reach maturity as commercial timber like those with nonna-

tive pines (Hanrahan, pers. comm., 2007). When compared to

other tree species in its native habitat, Araucaria araucana is

also a slower grower. In a mixed Nothofagus forest in South

America, for example, the average increment of growth of

Araucaria araucana trees each year was only 5– 8.2 cm in height

Dietary Options for the Sauropod Dinosaurs 37

FIGURE

3.1.

Paleogeographic map of the Late Jurassic (Kimmeridgian). Shown in black are the approximate locations of the three major

sauropod faunas discussed in this chapter. (1) Morrison Formation, Western Interior of North America. (2) Patagonia, southern South

America. (3) Tendaguru, Tanzania, Africa. Light gray indicates land; medium gray, highlands; and white areas within the black lines,

ﬂooded shelves. Map modiﬁed after Smith et al. (2004).

and 2.3–2.7 mm in diameter (Donoso et al. 2004). Among the

southern conifers—that is, the Podocarpaceae, Araucariaceae,

and half of the Cupressaceae—Araucaria and Agathis are mod-

erate in their growth rate (Enright & Ogden 1995).

Potential for Recovery

All extant members of the Araucariaceae have the ability to

regenerate branches or treetops that have been broken off by

way of epicormic and coppice buds (e.g., Burrows 1990; Bur-

rows et al. 2003), which are, respectively, dormant buds on the

trunk or at the base of the tree that are triggered into produc-

ing new growth after damage (Plate 3.1G, H). This trait pro-

vides a way to continuously regenerate new organs resulting

from damage that may occur through drought, small-scale

ﬁres, or blowdowns caused by tropical cyclones (e.g., Rigg et

al. 1998; Burrows et al. 2003; Gee, pers. obs.). In the Mesozoic,

this would have also been advantageous to the individual

trees after intense feeding on leafy branches and twigs by tall,

voracious sauropods, or damage by natural causes such as vol-

canic activity or ﬁre. Indeed, fossil structures representing the

dormant woody buds of conifers such as Araucaria mirabilis

(Spegazzini) Windhausen or Pararaucaria patagonica Wieland

have been collected from the Middle Jurassic Cerro Cuadrado

Petriﬁed Forest for many decades (Stockey 2002). It is thought

that these buds, called aerial lignotubers, may have developed

in the axils of leaves of conifers in this area in response to ﬁre

caused by volcanism, which was a repeated occurrence in the

Cerro Cuadrado sequence (Stockey 2002).

Digestibility

The in vitro digestibility of Araucaria foliage, based on sev-

eral trials with ﬁve different species, is very good (Hummel et

al. 2008). Leaves and pollen cones (Plate 3.1B, D, E) of Arau-

caria are moderately good in their digestibility, while foliage of

Agathis is weakly digestible (Hummel, pers. comm.). In con-

trast to other plants, Araucaria foliage provides little in the

form of protein (Hummel et al. 2008; Hummel & Clauss, this

volume) and thus would be less appropriate for young, grow-

ing animals requiring a high protein intake. It should be noted

that herbivore gut fermentation behavior of Araucaria foliage

rises slowly in the ﬁrst 30 hours of digestion, but ﬁnishes at a

relatively higher rate over the course of the next four days.

Such an energy release would be most advantageous to a large

animal with a long hindgut retention time, such as a giant-

sized adult sauropod dinosaur.

Consumption by Modern Herbivores

Although few vertebrates are known to feed on Araucaria,

there are reports of girdling (also known as ring barking) by

cockatoos in Northern Queensland, Australia (Hanrahan,

pers. comm. 2007). Araucaria seeds of the species that produce

large seeds, such as A. bidwillü, A. araucana, or A. angustifolia,

gee

are commonly eaten by rats, by large birds such as cockatoos,

parrots, crows, or jays, and by humans.

Co-occurrence with Major Late Jurassic

Sauropod Faunas

Fossils pertaining to Araucaria occur throughout most of the

Mesozoic, starting from the Late Triassic and extending beyond

the Late Cretaceous; they were globally widespread as well. Spe-

cies diversity within just the genus Araucaria was high during

this era, judging from the more than 30 different species of seed

cones that have been described (Gee & Tidwell 2010). In the

Morrison Formation, araucarian plant compressions (e.g., Plate

3.1C) and wood are abundant and in fact are by far the most

common plant fossils in a sauropod bonebed, the Howe-

Stephens Quarry on the Howe Ranch in north-central Wyoming

(Gee & Tidwell 2010). Palynologically, araucariaceous pollen is a

major element throughout the Morrison Formation, second

only to the Cheirolepidiaceae in terms of frequency (Hotton &

Baghai-Riding 2010). In Patagonia, araucarian cones and trees

are locally very common, for example at the Cerro Cuadrado

Petriﬁed Forest in Patagonia (e.g., Calder 1953; Stockey 1975,

1978; Zamuner & Falaschi 2005; Falaschi 2009). In Tendaguru,

araucarian cuticle occurs as a minor element of the ﬂora, but the

family also shows up throughout the Dinosaur Beds in the form

of wood, as well as several species of abundant pollen (Schrank

1999; Aberhan et al. 2002) that suggest the widespread domi-

nance of araucarians, especially in the Middle Saurian Bed

(Schrank 2010).

Remarks and Rating

In the Mesozoic, the Araucariaceae, especially Araucaria,

would have been a good source of food for large herbivores such

as adult sauropods. Not only were araucarian trees common all

over the world during most of the Mesozoic, but as a conse-

quence of their arborescent growth habit and probable occur-

rence in forests, they would have provided large amounts of

biomass for consumption. By extrapolating from fermentation

experiments with extant Araucaria species, it can be inferred that

the foliage and cones of the Mesozoic araucarians would have

been high in energy and most suitable for large animals with a

long hindgut retention time. On the basis of these parameters

and because of the intimate association of Araucaria with sau-

ropods in bonebeds or in sediments coeval with the major sau-

ropod faunas, it is quite likely that the Araucariaceae were a

frequent and attractive source of food for the sauropods.

EQUISETUM

Habit and Habitat

The genus Equisetum (Plate 3.2A), commonly known as the

scouring rush or horsetail, is represented by about 15 species

today. All species are perennial, although those in temperate

areas often die back to the ground in the winter. Most temper-

ate species are low-growing, attaining a height of up to about

1 m, although one species in Chile, E. giganteum, reaches 5 m

(Husby 2003). Characteristic of all species in the genus is their

occurrence in large monospeciﬁc stands, which they achieve

by spreading underground with horizontal stems called rhi-

zomes. Because Equisetum can produce extensive root systems

to tap sources of deep groundwater, it grows in seemingly

parched, disturbed habitats, such as gravels along railroad

tracks or dry, sandy riverbeds, although it is common to ﬁnd

extensive thickets of Equisetum in wet, marshy areas around

ponds or lakes, or along rivers.

Morphologically and anatomically, Equisetum has changed

very little since the Middle Triassic, down to the four strap-

shaped bands called elaters around its spores (Schwendemann

et al. 2010), which strongly suggests that it likely had the same

sort of growth habit and may have occupied the same sort of

moist habitats in the geological past as it does in the present

day. It is, for example, not uncommon to ﬁnd numerous axes

of Jurassic Equisetum, such as E. laterale (Plate 3.2B), amassed

on one slab, which also suggests that this species grew in pure

stands in the Mesozoic as it still does today (Harris 1961; Gee

1989; Cantrill & Hunter 2005; Gee & Sander, pers. obs.).

Biomass Production and Potential for Recovery

Because the stem of Equisetum is basically a hollow cylinder,

each individual shoot is composed of relatively little biomass.

However, taking into account the low, thicket-like growth of

Equisetum, a large colony around a lake or several populations

on a ﬂoodplain could amount to quite a signiﬁcant supply of

biomass for low-grazing herbivores.

Equisetum has a fast growth rate. Temperate species that die

back in the winter can produce a 1 m high shoot in a single

growing season. Gardeners are very familiar with the ability of

this plant to spread laterally in a relatively short period of time,

as well as with the difﬁculty of eradicating this weed because of

its extensive rhizome system. Similarly, damage to Equisetum

shoots—for example, due to herbivory—would not affect the

plant’s underground rhizomes and roots, which are protected

underground and would merely resprout new upright stems.

Digestibility and Consumption by Modern Herbivores

The energy yield of Equisetum, based on three species, is

excellent, exceeding that of all other plant groups, including

grasses (Hummel et al. 2008; Hummel and Clauss, this vol-

ume). Although silica is thought to hinder the digestibility of

cell walls (Van Soest 1994), the surface of Equisetum shoots,

which are rich in silica (e.g., Holzhüter et al. 2003), did not

seem to have much of a deleterious effect in the trials of Hum-

mel et al. (2008) and Hummel & Clauss (this volume). Further-

more, the digestibility of Equisetum rises very quickly within

Dietary Options for the Sauropod Dinosaurs 39

the ﬁrst 24 hours, which suggests that smaller herbivores with

a shorter gut retention time would have especially beneﬁted

from its consumption.

Despite possible negative effects of silica on digestion and

the purported abrasive effect of silica on mammalian teeth

(Sander, pers. comm.), several large herbivorous mammals in-

clude Equisetum as a key food plant in their diets. These include

caribou, moose, musk ox, dall sheep, and buffalo (Palmer

1944). Musk oxen, for example, commonly feed on horsetails

in the summertime, when they spend most of their time in

moist habitats (WMAC(NS) 2007). Similarly, many types of

waterfowl, such as Canada geese, lesser snow geese, pink-

footed geese, barnacle geese, and trumpeter swans, depend on

various species of Equisetum, especially during egg incubation

and after hatching (Thomas & Prevett 1982; Grant et al. 1994).

Even young birds, such as Icelandic pink-footed goslings, feed

extensively on E. arvense (Gardarsson & Sigurdsson 1972).

Trumpeter swan cygnets spend more time feeding on Equi-

setum than on submerged aquatic plants, as compared with

their parents (Grant et al. 1994). This is no wonder given the

high protein (22% dry weight) and high phosphorous content

of the rhizome tips and upright shoots of Equisetum—that is,

of E. ﬂuvatile—in late spring and summer (Thomas & Prevett

1982), when the needs for energy, protein, and minerals are at

their highest levels in geese (Thomas & Prevett 1982). In tropi-

cal regions, domestic cattle have been observed to graze on

Equisetum giganteum with relish (Hauke 1969).

Co-occurrence with Major Late Jurassic

Sauropod Faunas

Like Araucaria, Equisetum had a cosmopolitan distribution

in the Mesozoic from the Late Triassic onward, although there

are reports of the genus from the Carboniferous (Taylor et al.

2009). In the Late Jurassic of the Western Interior of North

America, several species of Equisetum have been reported from

Utah, Colorado, Wyoming, Montana, British Columbia, and

Alberta, including occurrences in sauropod bonebeds, such as

in the Mygatt-Moore Quarry in Colorado (Tidwell et al. 1998)

and the Howe-Stephens Quarry in Wyoming (Plate 3C; Gee,

unpublished data), or in beds that have yielded a typical as-

semblage of Morrison sauropods, namely, in the Como Bluff

‘‘Member’’ in Wyoming (Tidwell et al. 2006). At the last site,

Equisetum shoots are abundant and are represented by two

different species. In all cases, these shoots are slender and pre-

sumably pertain to short stems, attaining less than 1 m in

height. Several species of small-stature Equisetum have also

been described from Early Jurassic to mid Cretaceous ﬂoras

from both Patagonia (see recent summary by Villar de Seoane

2005; Falaschi et al. 2009) and the Antarctic Peninsula (e.g.,

Halle 1913; Gee 1989; Rees & Cleal 2004; Cantrill & Hunter

2005). Evidence of Equisetum has not yet been recovered from

the Tendaguru ﬂora (cf. Aberhan et al. 2002; Schrank 2010).

Remarks and Rating

In the Mesozoic, Equisetum (or Equisetites, as it is also known),

would have been a good source of food for all low-browsing

herbivores, especially young sauropods. Given their global

distribution, these plants were probably common in fresh-

water wetland areas, where they likely covered large areas

along shorelines and in this way provided much biomass for

consumption. The plant’s characteristic vigorous growth of

aerial shoots, protection of its main stem underground, and

deep root system would have helped to quickly regenerate

stands of Equisetum after intense feeding by herbivores. Fer-

mentation experiments with extant Equisetum species by

Hummel et al. (2008) show that the aerial shoots as well as

the tips of the rhizome offer herbivores a high-energy source

of high protein, phosphorous, and other nutrient content

that would especially beneﬁt young, fast-growing animals

such as young sauropods. The rapid digestibility of Equisetum

would have also been most advantageous to small or young

dinosaurs with a short gut retention time. Moreover, the short

stature of most horsetails in the past and their proximity

to sources of water would have enhanced their attractiveness

as a commonly sought-after food plant for young and smaller

sauropods.

CHEIROLEPIDIACEAE

Habit and Habitat

The family Cheirolepidiaceae is an extinct group of conifers

that was an important constituent of global ﬂoras during the

Mesozoic from the Late Triassic onward (Stewart & Rothwell

1993). In comparison to other conifer families, whether past

or present, the Cheirolepidiaceae show the greatest diversity

in regard to habit, habitat, and morphology. Some members

of the family were tall trees, for example, with a trunk diame-

ter up to about 1 m in one species (Francis 1983) or a height of

at least 23.4 m in another (Axsmith & Jacobs 2005). On the

basis of fossil wood studies on an in situ stand of cheirolepi-

diacean trees from the Late Jurassic of England, many of

the trees attained at least 200 years of age; the largest tree

was probably over 700 years old, indicating that there was a

lengthy history of continuity in this long-lived forest (Francis

1983). Although a nonarborescent habit is unusual among

conifers, other members of the Cheirolepidiaceae were herba-

ceous or scrubby, growing, for example, in low, dense stands

in a salt marsh setting (Jung 1974; Daghlian & Person 1977).

Cheirolepidiaceans grew in a variety of plant communities,

ranging from monospeciﬁc or low-diversity ﬂoras on hyper-

saline substrates or in brackish coastal swamps, to species-rich

assemblages in mesic, riparian settings (e.g., Daghlian & Per-

son 1977; Francis 1983; Gomez et al. 2002; Axsmith & Jacobs

gee

2005); they thrived in warm habitats under semiarid or even

arid conditions, as well as in strongly seasonal climates (Fran-

cis 1983), especially at low paleolatitudes ([40\) during the

Cretaceous (Taylor et al. 2009 and references therein).

There are two major kinds of foliage in the Cheirolepidia-

ceae: leaves that are spirally arranged with either scale-like or

spreading leaves (Brachyphyllum or Pagiophyllum type) and

leaves that clasp around the shoot with a jointed appearance

(Frenelopsis and Pseudofrenelopsis type) (Watson 1988). Despite

this diversity in leaf morphology, traits that unify the family

(Watson 1988) are the distinctive pollen Classopollis and, to a

lesser extent, thick cuticles with sunken stomata and papillae

that extend over the stomata (Plate 3.2E). It is thought that

some species bore ﬂeshy, succulent leaves (Watson 1988) and

that some species may have been deciduous (Behrensmeyer et

al. 1992).

Biomass Production and Potential for Recovery

The arboresent cheirolepidiaceans may have dominated the

woody vegetation in some areas, forming monospeciﬁc groves

or forests. In this case, their spreading branches and foliage

would have offered taller sauropods a large amount of bio-

mass. Similarly, the dense colonies of low-growing, halophytic

cheirolepidiaceans in the salt marshes of the Early Cretaceous

of Texas (Daghlian & Person 1977), which have a modern eco-

logical analog in the form of Salicornia (pickleweed), would

have also provided a plentiful source of food for small and

large sauropods alike. It is unknown how quickly cheirolepi-

diaceans grew or could regenerate after damage.

Digestibility and Consumption by Modern Herbivores

Because this group of plants does not have any close living

relatives, it is impossible to test foliage for digestibility, nor is it

possible to relate any accounts of consumption by modern

herbivores.

Co-occurrence with Major Late Jurassic

Sauropod Faunas

In the palynoﬂora of the Morrison Formation, Classopollis

pollen is extremely abundant in the southern states (New

Mexico and Arizona) and becomes increasingly less common

in the northern region (Hotton & Baghai-Riding 2010). Classo-

pollis pollen (also called Corollina) occurs throughout the Salt

Wash Member and older sediments at Dinosaur National

Monument in Utah (Litwin et al. 1998). Shoots with Brachy-

phyllum-type leaves bearing cuticle with papillae overhanging

the stomata occur at two sauropod bonebeds, the Mygatt-

Moore Quarry in Colorado (Tidwell et al. 1998) and the Howe-

Stephens Quarry in Wyoming (Gee, unpublished data); these

shoots likely pertain to the Cheirolepidiaceae. At Tendaguru,

both cuticle and pollen ﬂoras are dominated by the Cheiro-

lepidiaceae throughout most of the section, at times forming a

monotypical assemblage (Schrank 1999, 2010; Aberhan et al.

2002). The Cheirolepidiaceae have not yet been found in the

Jurassic of Patagonia, although the family does occur in the

Early Cretaceous of Argentina and Brazil as frenelopsid and

nonfrenelopsid foliage (Archangelsky 1963, 1966, 1968; Kunz-

mann et al. 2006).

Although the Cretaceous is technically beyond the scope of

this survey of co-occurrences, it is interesting to note that

Early Cretaceous cheirolepidiaceans occur in coastal sedi-

ments in Texas in which sauropod trackways and bonebeds

have been discovered. One species (Frenelopsis varians) was

collected from the Glen Rose Formation at a site northwest of

Austin, Texas, and grew in low colonies in salt marshes near a

hypersaline lagoon or bay depositional system (Daghlian &

Person 1977). A second species of Frenelopsis, F. ramosissima,

was found in a sauropod bonebed in the Twin Mountains For-

mation on the Jones Ranch southwest of Fort Worth and, in

contrast, formed a monospeciﬁc stand of massive trees in a

semiarid coastal forest (Axsmith & Jacobs 2005).

Remarks and Rating

Although the Cheirolepidiaceae no longer have any close

relatives on which we can run fermentation experiments or

measure biomass productivity, their habit as arborescent or

scrubby plants, dominance in xeric or saline habitats, and

general co-occurrence with sauropod during the mid and

late Mesozoic suggest that the members of this family have

constituted a major portion of a large sauropod’s diet. Fur-

thermore, as ﬁrst pointed out by Tiffney (1997), their leaves,

which have a succulent appearance, may have been quite pal-

atable to the herbivorous dinosaurs.

GINKGOPHYTES

Habit and Habitat

Ginkgo biloba (Plate 3.2F, G), the maidenhair tree, is the sole

surviving member of this group of plants, which once ﬂour-

ished in the Northern Hemisphere during the Mesozoic and

Paleogene (Stewart & Rothwell 1993). Ginkgos are long-lived

trees that can survive up to 3,000 years (Del Tredici 1991)

and usually attain heights between 20 and 30 m, but can reach

60 m in height (Del Tredici 1991; Schütt et al. 2004). Some

shrubby forms may have existed in the Mesozoic (Green 2005,

2007). A distinctive trait of the maidenhair tree is its fan-

shaped leaves, which turn a brilliant golden color in the fall

(Plate 3.2G). Today, Ginkgo is deciduous, and it is commonly

assumed that ginkgophytes were deciduous in ancient times

too (e.g., Spicer & Parrish 1986). The natural distribution of

Ginkgo biloba is limited to a small, refugial area in southeastern

China, which has a mesic, warm-temperate climate (Del Tre-

dici 1992b). However, G. biloba is widely cultivated in areas

Dietary Options for the Sauropod Dinosaurs 41

with cold temperate, warm temperate, and Mediterranean cli-

mates (Del Tredici 2007), and is thus well known for its broad

environmental tolerance in regard to moisture, temperature,

and topography.

Biomass Production

Because of its economic importance in medicine, the har-

vesting of Ginkgo biloba leaves has received some attention,

especially in Asia. It was found on a 15 year old plantation in

central Korea that the above-ground biomass of Ginkgo, which

includes stem wood, stem bark, branches, and foliage, equaled

23,780 kg/ha (Son & Kim 1998). This falls within the range of

biomass values for 10–20 year old stands of conifers, which

vary from 15,000–70,000 kg/ha (Kimmins et al. 1985). The

foliage-only biomass on the Korean Ginkgo plantation made

up 10% of the above-ground tree biomass, which is consid-

ered a relatively large proportion (Son & Kim 1998).

In the leaf biomass experiments of Hummel & Clauss (this

volume) in which the distal 30 cm of foliage of various tree

species were stripped, dried, and weighed, Ginkgo biloba pro-

duced 8.8 † 3.0 g in dry matter, compared to an average of

4.2 † 1.6 for six different broad-leaved trees, an increase of

more than twice as much biomass for Ginkgo over the angio-

sperms.

Potential for Recovery

As a deciduous gymnosperm, Ginkgo biloba sheds its leaves

every year, which means that it will renew its foliage annually

in any case. It also has two kinds of lignotubers—sometimes

called basal chichi and aerial chichi—that will propagate new

trunks or branches from the parent plant vegetatively in the

event of traumatic damage or changes in substrate stability

(Del Tredici 1992a, 1992b). In fact, a Ginkgo biloba growing in

the center of the atomic blast over Hiroshima, which had its

trunk completely destroyed in 1945, is survived by a new tree

that sprouted from its base by way of its basal lignotubers (Del

Tredici 1991). These dormant woody buds may be the key to

ginkgo’s longevity through the centuries as well as through

geological time, as reproduction by seeds appears to be mostly

unsuccessful, especially in closed-canopy forests (Del Tredici

1992a, 1992b, 2007). This is due in great part to seed predation

(see below) and to the low-light conditions in a closed forest.

It has been observed that the small natural populations of

Ginkgo on Tian Mu Shan near Hangzhou, China, occur today

on disturbance-generated microsites with soil erosion such as

on stream banks, rocky slopes, and edges of exposed cliffs.

A preference for disturbed habitats would have been advan-

tageous for the germination and establishment of new ginkgo

trees in the wake of any trampling, soil-churning sauropods

feeding on older ginkgo stands, although it would have taken

some decades before the ginkgo seeds and saplings grew into

good-sized trees.

Ginkgo biloba is a slow grower. In plantations in its native

habitat on Tian Mu Shan, China, and in Virginia, USA, the

average growth rate was 21 cm/yr and 34 cm/yr for trees 25 and

35 years old, respectively (Del Tredici 2004). A more vigorous

average growth rate of 48 cm/yr was measured on the 15 year

old plantation in Korea mentioned above (Son & Kim 1998).

Digestibility and Consumption by Living

Animals and Humans

In laboratory fermentation experiments (Hummel et al.

2008), the energy yield of Ginkgo biloba was found to be good.

Among the many plant groups tested by Hummel et al. (2008),

Ginkgo biloba leaves yielded by far the most crude protein, sur-

passing the percentage in dry matter of Equisetum (the next

best source of crude protein) by 1.3 times and that of arau-

cariaceous leaves (the worst source of crude protein among

the Mesozoic plant types tested) by 3.5 times (Hummel, pers.

comm.).

The nutritious seeds of the extant ginkgo tree are consumed

by a number of different animals. Tree squirrels in North

America and China, such as the red-bellied squirrel on Tian

Mu Shan, feed on the ginkgo ‘‘nuts,’’ and humans, especially

in Asia, have eaten the boiled seeds for centuries (Del Tredici

1991). In addition, three omnivorous members of the Car-

nivora, the leopard cat and the masked palm civet in China

and the raccoon dog in Japan (Del Tredici 1992b, 2008), feed

on ginkgo ‘‘berries’’—the inner seed surrounded by a ﬂeshy,

foul-smelling seed coat. Indeed, the droppings of the raccoon

dog have been found to contain intact seeds, which then ger-

minated the next spring (Rothwell & Holt 1997). The feeding

of these nocturnal scavengers on ginkgo nuts has led Del Tre-

dici (1992b) to speculate that the foul-smelling seed coat of

Ginkgo attracts animal dispersers by posing as a carrion mimic.

In regard to its foliage, Ginkgo biloba is reputed to be quite re-

sistant to damage from insects, fungi, bacteria, and viruses (Del

Tredici 2004). Although there are some modern insects that

feed on Ginkgo leaves, their number is extremely small com-

pared to that attacking other gymnosperms (Honda 1997).

Consumption by Fossil Animals

In the Cretaceous–Paleogene boundary fossil ﬂora in North

Dakota, the leaves of Ginkgo adiantoides show a few types of

insect damage (Labandeira et al. 2002).

Co-occurrence with Major Late Jurassic

Sauropod Faunas

Several species of Ginkgo leaves (Brown 1975; Ash & Tidwell

1998), as well as pollen (Hotton & Baghai-Riding 2010), occur

throughout the Morrison Formation, from Canada to Colo-

rado and Utah. Ginkgo seeds have been found in Utah and

Montana (Tidwell 1990b), while Ginkgo foliage co-occurs with

sauropod remains at the Mygatt-Moore Quarry in western

gee

Colorado (Tidwell et al. 1998). At Tendaguru, ginkgo cuticle

does occur, but it is less commonly preserved than conifer

cuticle (Kahlert et al. 1999; Aberhan et al. 2002).

Remarks and Rating

The ginkgophytes would have been a good source of energy

and protein for medium-sized to large herbivores in the

Northern Hemisphere throughout the Mesozoic. As a conse-

quence of their arborescent growth habit and production of

abundant leaves, they would have provided much biomass for

consumption during times of the year when the trees bore

leaves. Moreover, mature trees with ginkgo nuts would have

provided taller sauropods with additional nutrition when

fruiting. The trees may have occupied more open or disturbed

habitats, which might have enabled larger animals more room

for maneuvering, and any damage to branches, the trunk, or

the base of the tree during feeding might have not perma-

nently harmed the tree, but instead activated its dormant

growth buds. Extrapolating from the good energy content of

Ginkgo biloba, as well as from the frequent association of

Ginkgo fossils and sauropod remains in the Late Jurassic Mor-

rison Formation, it is likely that Ginkgo leaves and its fructiﬁ-

cations may have been a good, attractive source of nutrition

for larger herbivores in the Northern Hemisphere.

PODOCARPACEAE

Habit and Habitat

The Podocarpaceae are a large family of mostly evergreen

conifers, consisting of about 18 genera and 170–200 species

(Hill 1995). Podocarpus is the largest genus in the family and

forms either trees from 20–30 m or occasionally 40 m in

height, or shorter, single- or multistemmed shrubs from 4–12

m in height (Krüssmann 1972). Most members of the family

are native to the warm temperate and subtropical zones of

the Southern Hemisphere, although a few species do occur

in Japan, China, Malaysia, and the Philippines (Krüssmann

1972). The taller trees can dominate the canopy layer in mid

to upper montane forests and can live longer than 1,000 years.

Podocarps are forest forming, as in New Zealand, where they

make up dense podocarp-dominated forests, as well as mixed

podocarp–hardwood forests (Ogden & Stewart 1995).

This family has a long history of plant megafossils and pol-

len extending back to the Early Triassic (Taylor et al. 2009).

Nearly all fossils occur in the Southern Hemisphere (Hill

1995), although there are a few reports of megafossils (e.g.,

from China; Zhou 1983) and pollen (e.g., from the Morri-

son Formation, USA; Hotton & Baghai-Riding 2010) from the

Mesozoic of the Northern Hemisphere as well. Although ex-

tant podocarps have free, spreading leaves, it should be noted

that podocarpaceous foliage described from the Mesozoic and

Cenozoic of Australasia resembles Brachyphyllum and Pagio-

phyllum (Gee, pers. obs. based on specimens ﬁgured by Hill

1995), which are two form genera with short leaves closely

appressed to the shoot axis that are common in the Mesozoic

ﬂoras all over the world.

Biomass Production and Potential for Recovery

In general, most members of the Podocarpaceae are very

slow growers, even when compared to other relatively slow-

growing conifers (Enright & Ogden 1995) or when growing

under benign conditions. For example, the net primary pro-

duction of a 35 year old plantation of Podocarpus imbricatus on

the tropical island of Hainan, China, averaged 10.3 metric

tons per hectare and year, reaching a maximum of 14 metric

tons per hectare and year (Chen et al. 2004). The former value

is much lower than the usual net primary production of tropi-

cal forests, and is instead roughly equivalent to that of warm

temperate forests (cf. Lieth 1975).

Some species of Podocarpus are known to possess epicormic

shoots, similar to those in the Araucariaceae.

Digestibility and Consumption by Modern Animals

The digestibility of three different genera (Podocarpus, Dacry-

dium, Phyllocladus) in this family proved to be poor (Hum-

mel, pers. comm.), and the family Podocarpaceae was one of

the worst plant groups in the experimental trials of Hummel et

al. (2008).

A ﬂeshy tissue around podocarpaceous seeds called the epi-

matium (Plate 3.2H) adds to their attractiveness as a food op-

tion; such seeds are part of the normal diet of animals such as

brushtail opossums (Podocarpus hallii and Dacrydium cupressi-

num seeds) or ship rats (Prumnopitys ferruginea seeds) in mixed

podocarp–hardwood forests in New Zealand (Sweetapple &

Nugent 2007). The opossums rely on P. hallii as their main

food on both North Island and South Island of New Zealand

(Nugent et al. 1997 and references therein; Rogers 1997; Bell-

ingham et al. 1999). In fact, opossums bulk feed on the P. hallii

leaves all night when feeding in the canopy layer (Rogers

1997). Strangely, in the same mixed podocarp–hardwood for-

ests, P. hallii is avoided by browsing red deer. Indeed, red deer

in a temperate forest heavily dominated by Podocarpus nagii

also avoid eating podocarp leaves of this species, even in feed-

ing trials (Ohmae et al. 1996). This is thought to be due to

the antiherbivory effect of nagilactones in the leaves (Ohmae

et al. 1996).

Co-occurrence with Major Late Jurassic

Sauropod Faunas

As mentioned earlier, fossil shoots with leaves that have

been unequivocally identiﬁed as podocarpaceous elsewhere

resemble the form genera of Brachyphyllum and Pagiophyllum

that pertain to the foliage of the Araucariaceae and Cheiro-

Dietary Options for the Sauropod Dinosaurs 43

lepidiaceae. Several species of Brachyphyllum and Pagiophyllum

are known from the Morrison Formation (Tidwell 1990b; Ash

& Tidwell 1998; Tidwell et al. 1998, 2006), but none of them

have been assigned to the Podocarpaceae. In contrast, 16 form

taxa pertaining to podocarpaceous pollen have been de-

scribed from many parts of the Morrison Formation (Hotton

& Baghai-Riding 2010). The Podocarpaceae are also a com-

mon element in the Tendaguru ﬂora, appearing in all or most

of the units as wood, cuticle, or pollen (Aberhahn et al. 2002;

Schrank 2010). In Patagonia, the Podocarpaceae ﬁrst appear in

the Triassic (Troncoso et al. 2000) and continue to show up as

pollen, wood, leaves, and pollen and seed cones throughout

the Mesozoic (e.g., Del Fueyo 1996 on pollen; Gnaedinger

2007 on wood; Taylor et al. 2009 and references therein on

compression fossils).

Remarks and Rating

Assuming the Podocarpaceae had the same woody habits

and forest habitats in the Mesozoic as they do now, and con-

sidering their co-occurrence with the sauropod faunas, es-

pecially in the Southern Hemisphere, they would have been

a common food plant for herbivorous dinosaurs. However,

in view of their poor fermentation values, which translate

into comparatively low amounts of energy in each bite, slow

growth rates, and documented unpalatability to some large

present-day herbivores (red deer), the Podocarpaceae may

have been a less sought-after source of food compared to other

gymnosperms such as Araucaria, the Cheirolepidiaceae, and

ginkgophytes.

OTHER CONIFERS

Living conifers make up a large group of plants, called the

Pinophyta or Coniferae, consisting of 7 families, 69 genera,

and roughly 600 species (Earle 2009a). Two extant families

(Araucariaceae and Podocarpaceae) have been discussed here

separately as a result of their dominance in Mesozoic ecosys-

tems. The remaining families are the Cupressaceae, Pinaceae,

Taxaceae, Cephalotaxaceae, and Sciadopityaceae. It should also

be noted that the Taxodiaceae are now generally regarded as part

of the Cupressaceae, with the exception of Sciadopitys, which is

now commonly put into a separate family of its own. Because

the Taxaceae and Cephalotaxaceae have poor fossil records

and the Sciadopityaceae ﬁrst appears in the Late Cretaceous

(Taylor et al. 2009), these families will not be treated here.

CUPRESSACEAE

Habit and Habitat

The Cupressaceae comprise a large family that includes

about 27 genera and 127 species (Mabberley 1993) of shrubs

or, more commonly, trees, which can attain heights up to 112

m (Sequoia sempervirens, the coast redwood; Lanner 2002). The

trees in this family are also notable for being the largest (Se-

quoiadendron giganteum, the giant sequoia), the stoutest (Taxo-

dium mucronatum, the Montezuma cypress or ahuehuete), and

the second longest lived (Fitzroya cupressoides, the alerce) in

the world. The Cupressaceae are the most widely distributed

family of conifers and can be found on all continents except

for Antarctica (Earle 2009b). Accordingly, they are found in a

variety of habitats ranging from coastal settings, ﬂoodplains,

freshwater swamps (Plate 3.3A), riverbanks, and mountains,

and they thrive under various climatic regimes, which include

tropical, subtropical, warm temperate, and semiarid condi-

tions (Burns & Honkala 1990).

The oldest fossil generally accepted as pertaining to the

Cupressaceae occurs in the Middle Triassic (Yao et al. 1997). A

more solid fossil record of the family shows up in the Jurassic,

and the worldwide distribution of the Cupressaceae becomes

apparent in the Cretaceous (Taylor et al. 2009).

Biomass Production and Potential for Recovery

As large trees with spreading branches, like the other conifer

families described in this chapter, the members of the Cupres-

saceae offer quite a bit of biomass. Some members of the fam-

ily, such as Sequoia sempervirens, have such a high growth rate

that, of all the world’s vegetation types, a mature coast red-

wood forest produces the greatest biomass per unit area, even

exceeding that of tropical forests (Lanner 2002). In its ﬁrst

year, a coast redwood sapling can grow up to 1.8 m in height

(Lanner 2002). Sequoiadendron giganteum, Metasequoia glypto-

stroboides, and Glyptostrobus pensilis are other examples of fast-

growing members of the family (Schütt et al. 2004).

Like araucarians and ginkgoes, some cupressaceous genera

have the capacity to regenerate from lignotubers, known in

many conifers as burls, after injury or death to the parent

tree. In the case of the coast redwood, for example, these dor-

mant growth buds are located along its roots, allowing it to

form lines of clones up to 30 m long after damage by ﬁre

(Lanner 2002).

Digestibility and Consumption by Modern Animals

The in vitro fermentation of the Cupressaceae in the labora-

tory experiments of Hummel et al. (2008) was good. On the

basis of 11 samples from a variety of genera, the average

amount of digestibility nearly matches that of Ginkgo.

The wood of some cupressaceous trees, for instance, Juni-

perus virginia, Sequoia sempervirens, and Callitris glaucophylla,

can contain a compound that smells like camphor and deters

insects, especially termites. However, the foliage of the trees in

this family seems to be palatable to large herbivores. Juniperus

communis, J. occidentalis, J. californica, and Austrocedrus chilen-

sis are, for example, commonly heavily browsed by livestock

gee

such as goats (e.g., Zanoni & Adams 1973; Torrano & Valder-

rábano 2005) and deer, especially red deer (Relva & Veblen

1998).

Co-occurrence with Major Late Jurassic

Sauropod Faunas

Foliage and wood of the Cupressaceae occurs in the Morrison

Formation (e.g., Tidwell 1990b; Ash & Tidwell 1998; Tidwell et

al. 1998). Wood assigned to the morphogenus Glyptostroboxy-

lon, which may pertain to the Cupressaceae/Taxodiaceae, is

also found at Tendaguru (Kahlert et al. 1999; Süss & Schultka

2001; Aberhan et al. 2002). In Argentina, cupressaceous wood

has been reported from the Jurassic (Gnaedinger 2004), and

leafy twigs with seed cones occur in the mid Cretaceous of

Argentina (Halle 1913; Archangelsky 1963; Villar de Seoane

1998; Llorens & Del Fueyo 2003; Del Fueyo et al. 2008).

The ﬁrst convincing evidence of the Cupressaceae from the

Jurassic—a new genus and species (Austrohamia minuta) of

leafy twigs and branches bearing seed and pollen cones—was

recently described from Patagonia (Escapa et al. 2008).

Remarks and Rating

With an arborescent habit, spreading branches, the ability

to thrive in a variety of habitats, and good digestibility, the

trees of the Cupressaceae in the widest sense (that is, including

the basal members of the former Taxodiaceae) would have

been a good source of nutrition for the sauropod dinosaurs.

Taking into consideration their general co-occurrence with

the major sauropod faunas in both hemispheres, as well as the

palatability of cupressaceous leaves to extant herbivores, the

foliage of this conifer family may have comprised a good por-

tion of a herbivorous dinosaur’s diet.

PINACEAE

Habit and Habitat

Like most conifers, the Pinaceae are predominantly ever-

green trees and are rarely deciduous or shrubs (Plate 3.3B);

they bear needle-like foliage and woody seed cones (Plate

3.3C). There are 9 genera and 194 species in this family, nearly

all of which are concentrated in the Northern Hemisphere

(Krüssmann 1972; Mabberley 1993). The Pinaceae form for-

ests, with most trees growing to a maximum height of 30 to

40 m, although a few can reach 87 m (Krüssmann 1972). This

family dominates the boreal forest—the world’s largest biome

—as well as most temperate and boreal mountain forests and

semiarid woodlands (Earle & Frankis 2009). Like the Cupressa-

ceae, the members of this family can also be found in coastal

settings (Plate 3.3B), in freshwater swamps, and on ﬂood-

plains (Burns & Honkala 1990). Pinaceous trees have great

longevity; the longest lived organisms on earth, the bristle-

cone pines (Pinus longaeva and P. aristata), pertain to the

Pinaceae (Lanner 2002). The genera Abies (ﬁr), Cedrus (cedar),

Larix (larch), Picea (spruce), Pinus (pine), Pseudotsuga (Douglas

ﬁr), and Tsuga (hemlock spruce) are especially well known

because they are important sources of timber and pulp, tur-

pentine, resins, cultivated ornamentals, and edible seeds

(Mabberley 1993). Indeed, the family Pinaceae are economi-

cally and ecologically the most important gymnosperm fam-

ily on earth (Earle & Frankis 2009).

From the diversity of seed cones in the Cretaceous, it is

thought that the Pinaceae was well established early in the

Mesozoic (Taylor et al. 2009). One of the oldest members of

this family is represented by the seed cone Compsostrobus from

the Late Triassic of North Carolina (Delevoryas & Hope 1973,

1987).

Biomass Production and Potential for Recovery

Many trees in the Pinaceae exhibit a classical Christmas tree

shape, with long, downward-drooping branches. Combined

with their ability to form forests, this would offer much bio-

mass for browsing herbivores. Growth rates are variable in

the family. Early growth in Tsuga canadensis, for example, is

extremely slow, and trees with a d.b.h. (diameter at breast

height, a standard forester’s measurement) of less than 2.5 cm

(1 inch) may be as old as 100 years (Godman & Lancaster

1990). On the other hand, Pinus halepensis is a fast grower and

can attain a height of 30 cm in its ﬁrst year (Schütt et al. 2004).

Regeneration in the Pinaceae is also variable. Although

some members of the family (e.g., Pinus virginiana) do not

show any resprouting (Carter & Snow 1990), many more re-

sprout readily in response to injury, particularly ﬁre, sending

up new shoots from epicormic buds in the needle fascicles and

leaf axils, along the trunk, or from the roots. This latter group

includes species of Picea, Pinus, Pseudotsuga, and Tsuga (Earle &

Frankis 2009).

Digestibility and Consumption by Modern Herbivores

The digestibility of the Pinaceae in the in vitro fermentation

experiments of Hummel et al. (2008) is good.

Contrary to common belief, large herbivores such as forest

ungulates commonly feed on these conifers; they eat leaves,

strip bark, and tend to decimate saplings between 10 to 40 cm

high (e.g., Bergström & Bergqvist 1997; Kupferschmid & Bug-

mann 2005). For example, red deer, roe deer, and chamois feed

on Norway spruce (Picea abies) in European forests (Kupfer-

schmid & Bugmann 2005), while sika deer browse on young

Japanese larches (Larix kaempferi) in Japan (e.g., Akashi 2006).

A wide range of animals have been documented as feeding on

eastern hemlock (Tsuga canadensis), causing serious dam-

age, loss of vigor, slowing of growth rate, or death to the tree;

Dietary Options for the Sauropod Dinosaurs 45

these animals include white-tailed deer, snowshoe hares, New

England cottontails, mice, voles, squirrels and other rodents,

porcupines, and sapsuckers (Godman & Lancaster 1990).

White-tailed deer and rabbits are also known to browse on

young sprouts and seedlings of pitch pine (Pinus rigida; Little

& Garrett 1990). Meadow voles girdle young trees of Virginia

pine (Pinus virginiana), preferring it over other species in

the area (Carter & Snow 1990), and were responsible for dev-

astating seedling plantations of Norway spruce (Picea abies)

and Norway pine (Pinus resinosa) in Canada during a vole

population density peak in 1987–1988 (Bucyanayandi et al.

1990).

A number of species of Pinus produce large, edible seeds,

namely the pinyon pines and stone pine, which are eaten by

squirrels, a variety of birds, and humans. For instance, the

nutcracker and pinyon jays cache huge numbers of pinyon

pine seeds each year, which are eaten later by the birds in the

winter or left to germinate the coming spring (Lanner 2002).

In whitebark pine, uneaten seeds cached by Clark’s nutcrack-

ers are the only reliable means for the species to regenerate

itself (Lanner 2002). Even species of Pinus with smaller seeds,

such as P. rigida, are an important food for squirrels, quail, and

small birds such as the pine warbler, pine grosbeak, and black-

capped chickadee (Little & Garrett 1990).

Insect herbivory on seed cones is evident in the recent as

well as in the fossil record. Tunneled borings ﬁlled with frass

of boring beetles in a mid Cretaceous pinaceous seed cone

resemble the infestation of boring beetles of the genus Conoph-

thorus on seed cones of living Pinus spp., which eat through the

nutritive tissues of the vascular cambium, phloem, and cortex

of the cone (Falder et al. 1998).

Co-occurrence with Major Late Jurassic

Sauropod Faunas

Pinaceous foliage (commonly called Pityocladus or Pityophyl-

lum) and wood are known from the Late Jurassic Morrison For-

mation (Tidwell 1990b; Ash & Tidwell 1998). Bisaccate pollen

grains typical of this family are found throughout the Mor-

rison Formation as well (Hotton & Baghai-Riding 2010). Fossil

remains of the Pinaceae do not occur at Tendaguru or in Pata-

gonia, nor would it be expected to ﬁnd them there because

this family had its main distribution in the Northern Hemi-

sphere during the Mesozoic, as it does today (Taylor et al.

2009).

Remarks and Rating

For the same reasons as in the Cupressaceae—a tree habit

with long, spreading branches, the ability to thrive in a num-

ber of different habitats, and good digestibility—the Pinaceae

would have been good food plants in the Mesozoic, albeit

only in the Northern Hemisphere.

FERNS

Today, the ferns comprise a large division of plants, known as

the Filicophyta, containing some 20,000 species. Although

ferns can occur as epiphytes on trees or as ﬂoating macro-

phytes in freshwater, the ferns of interest here are ground-

dwelling forms with a long fossil history, such as the families

Marattiaceae and Osmundaceae.

MARATTIACEAE

Habit and Habitat

The Marattiaceae are a family of tropical ferns, with either

leaves arising near ground level from an underground rhi-

zome or elevated to the top of a tree-like trunk (Kramer et al.

1995). The 6 genera and roughly 260 species of this family

grow in rain forests under year-round uniform conditions

of high temperature and high humidity (Christenhusz 2009),

often in wet soils and shady spots (Jones 1987). The center of

diversity of the family today is in the Asian tropics (cf. Chris-

tenhusz et al. 2008).

The order Marattiales has an extensive fossil history that

extends back to the Early Carboniferous, about 300 million

years ago (Taylor et al. 2009), while fossil leaves identical to

those of the extant genera Marattia, Danaea, and Angiopteris

have been recorded as far back as the Late Triassic, Early Juras-

sic, and Middle Jurassic, respectively (e.g., Harris 1931; Hill

1987; Stewart & Rothwell 1993; Yang et al. 2008).

Biomass Production and Potential for Recovery

The largest member of the extant Marattiaceae, the king

fern Angiopteris evecta, produces large, robust fronds that can

reach lengths of 8 m. However, admittedly little is known

about its growth rate and longevity in its native habitat, al-

though it is under protection as an endangered species in parts

of Australia (NSW National Parks and Wildlife Service 2001).

Once established, the fronds of Angiopteris are massive and ro-

bust, although growth is presumably slow. Even under ideal

horticultural conditions, the propagation of Marattia by

spores, for example, proceeds at an extremely leisurely pace,

taking up to four years to produce a plant about 5 cm high

(Large & Braggins 2004).

Digestibility and Consumption by Modern Herbivores

The digestibility of Angiopteris evecta leaves is excellent, the

best of all the ferns tested by Hummel & Clauss (this volume),

and after 72 hours, it reaches the energy yield of grasses (Hum-

mel et al. 2008). Like Equisetum, the rate of fermentation of

Angiopteris is greatest within the ﬁrst 24 hours of digestion.

There are reports of insect damage on living leaves of Marat-

gee

tia and Angiopteris (Beck & Labandeira 1998), but it is not

known whether vertebrates also feed on these ferns today.

Co-occurrence with Major Late Jurassic

Sauropod Faunas

As mentioned above, fossils of Marattia, Danaea, and An-

giopteris are known from the Mesozoic, but they have not been

found in association with the major sauropod faunas from the

Morrison Formation, Tendaguru, or Patagonia.

Remarks and Rating

Although Angiopteris yields a remarkably high amount of

energy, especially for a fern, it is doubtful whether this genus,

along with Marattia and Danaea, formed a major part of a

giant sauropod’s diet. Not only would the general habitat of

marattiaceous ferns in dense, closed-canopy rain forests have

been less accessible to the larger sauropods, but the slow

growth and propagation of living marattiaceans also suggests

that there would have been a poor response of their Mesozoic

relatives to intense herbivore feeding pressure. Furthermore,

the lack of intimate association with major sauropod faunas

in the fossil record also suggests a lack of opportunities for

plant–herbivore interactions.

OSMUNDACEAE

Habit and Habitat

The Osmundaceae are represented today by three genera

that form fronds near ground level (Osmunda, Plate 3.3D) or

sometimes at the top of tree-like stems (Todea, Plate 3.3E, and

Leptopteris). These ferns prefer moist, poorly drained condi-

tions in open or closed-canopy habitats such as stream banks,

damp woods, moist forests, and acidic swamps in temperate

and subtropical areas (Jones 1987; Kramer et al. 1995).

The family has an extensive fossil record, extending back to

the Permian (Stewart & Rothwell 1993). In Jurassic sediments,

osmundaceous rhizomes are abundant and occur all over the

world, but are most common in the Southern Hemisphere

(Tian et al. 2008). The existence of Osmunda and Todea in the

Middle Triassic and Late Cretaceous, respectively, document

the longevity of these genera (Jud et al. 2008). Indeed, one

living species (O. cinnamomea, the cinnamon fern in the east-

ern North America) has remained unchanged since the Late

Cretaceous (Serbet & Rothwell 1999).

Biomass Production and Potential for Recovery

The fronds of osmundaceous ferns range from relatively

small (less than 1 m long; Leptopteris) to moderately large (2–

4 m long; Osmunda and Todea). O. cinnamomea commonly

grows in monospeciﬁc colonies and, like Equisetum, can form

dense thickets.

Osmunda cinnamomea readily resprouts from its under-

ground rhizomes after its aerial portions have been destroyed

by ﬁre, exhibiting vigorous rhizome growth after ﬁre damage,

and in fact does best in areas that regularly experience burning

(Walsh 1994). Once established, individual plants of Osmunda

are reported to grow relatively fast, but it has also been noted

that the rate of vegetative spreading in Osmunda, Todea, and

Leptopteris is slow (Walsh 1994; Large & Braggins 2004).

Digestibility and Consumption by Modern

Herbivores and Humans

Osmunda and Todea have vastly different fermentation

curves. Osmunda is a good/excellent producer of energy, simi-

lar to grasses and forbs, while Todea is a poor producer of en-

ergy and has the second to worst fermentation curves (Hum-

mel, pers. comm.). Hence, a herbivore would be wiser in

regard to energy intake to graze on Osmunda than on Todea.

Livestock and white-tailed deer like to feed on Osmunda cin-

namomea, especially on tender fronds that are no older than a

month (Walsh 1994). In fact, cattle prefer to browse cinna-

mon ferns second only to cane (Arundinaria gigantea). Young

fronds of O. cinnamomea can also be steamed or boiled and

eaten by humans (Elias & Dykeman 1990).

Co-occurrence with Major Late Jurassic

Sauropod Faunas

Two genera of the Osmundaceae, the tree ferns Osmundacau-

lis and Ashicaulis (Tidwell & Rushfort 1970; Tidwell 1990a,

1994), occur in the Morrison Formation and are abundant near

Ferro and Moab in Utah (Tidwell 1990b), although the plant

remains are not directly associated with any sauropod remains.

Nevertheless, the spores of the family (Baculatisporites, Osmun-

dacites, and Todisporites) occur laterally and vertically through-

out the Morrison Formation (Litwin et al. 1998; Hotton &

Baghai-Riding 2010), indicating that they were part of the re-

gional vegetation. At Tendaguru, the spores of Todisporites and

Osmundacites show up in the palynoﬂora (Schrank 1999, 2010).

Although several species of osmundaceous rhizomes have

been reported from southernmost Patagonia, none of them

occur in the Late Jurassic (Tian et al. 2008). However, the form

genus Cladophlebis, which is thought to pertain to the Os-

mundaceae, occurs throughout the Triassic and Jurassic of Ar-

gentina and the Antarctic Peninsula (e.g., Herbst 1971; Gee

1989). Fossil Cladophlebis leaves (Plate 3.3F) are twice pinnate

and robust, closely resembling the fronds of extant Osmunda

(Plate 3.3D) and Todea (Plate 3.3E). Fertile pinnules known as

Todites bearing small, round, densely packed sporangia are

similar to the sporangia-bearing pinnules of living Todea.

Remarks and Rating

The Osmundaceae, especially Osmunda, may have formed a

recurrent but minor part of the sauropod diet in mesic habi-

Dietary Options for the Sauropod Dinosaurs 47

tats, given its high energy content, dense thicket-forming

habit, high palatability to some grazers and browsers, and co-

eval occurrence in the Morrison and Tendaguru sediments. If

a parallel can be drawn between the rapid regeneration of

fronds and the new colonization of disturbed areas after ﬁre

in recent environments and sauropod herbivory in Mesozoic

times, Jurassic Osmunda rhizomes may have responded with

vigorous regrowth of their fronds after being cropped.

CYCADS AND BENNETTITALEANS

The Cycadales (the true cycads; Plate 3.3G) and Bennettitales

(also called the Cycadeoidales; Plate 3.3H) are two different

groups of gymnosperms with similar growth forms and leaf

morphology. These plants, which are commonly treated to-

gether as the cycadophytes, have pinnately compound leaves

that are so similar that at times they can only be distin-

guished from one another by details of epidermal features

such as stomata. The organization of their cones was very dif-

ferent, however, and this supports the continued separation

of the enigmatic Bennettitales from the Cycadales (cf. Crepet

& Stevenson 2010). Although cycads ﬁrst showed up in the

Paleozoic and continue to the present day, bennettitaleans

occurred exclusively in the Mesozoic.

Habit and Habitat

Cycads have long, evergreen, pinnately compound fronds.

Their stems commonly form stout or tall, upright trunks and

are covered with a mantle of hard, woody leaf bases. There are

12 genera and over 300 species in the family (Chaw et al.

2005), and individual plants can live several hundred years.

Cycads occur today in the tropical, subtropical, and warm

temperate regions of both the Northern and Southern Hemi-

spheres, ranging northward from the southern islands of the

Japanese archipelago and southward to southern parts of Aus-

tralia, while the center of diversity of the cycads is in Central

America (Jones 1993). They can be found in mesic habitats,

such as rain forests, as well as in semiarid to xeric environ-

ments, such as grasslands and sparse woods, and on rocky

escarpments and in gorges (Jones 1993). Cycads have a long

fossil history that stretches back to the Carboniferous and

continues until today. They reached their heyday during the

Mesozoic in regard to geographic distribution and number of

taxa (Taylor et al. 2009).

The fronds of the bennettitaleans, on the other hand, look

similar to those of the cycads, but are commonly much shorter

in length. Their stems can appear stout and trunk-like, similar

to those of the cycads, or massively globose in shape. Like the

cycads, they were a characteristic feature of the landscape in

the Mesozoic. In Patagonia, for example, bennettitaleans were

shrubby plants that formed the understory vegetation along-

side corystosperms (a type of seed fern; see below) in a vari-

ety of forest types (evergreen, deciduous, sclerophyllous) or

grew in open areas as shrubs in the Triassic (Artabe et al. 2001;

Cúneo et al. 2010). In the Cretaceous of Patagonia, bennettita-

leans, as well as cycads, show morphological features adapted

to warm and seasonally dry climates, due at least in part to the

constant volcanic activity in the region (Archangelsky et al.

1995; Archangelsky 2003; Cúneo et al. 2010). Thus, like cy-

cads, bennettitaleans could grow in a variety of environments

ranging from mesic to xeric habitats.

Biomass Production and Potential for Recovery

Among gardeners and horticulturalists, cycads are notori-

ous for being slow growers. Cycads do not develop new leaves

continuously but produce a burst or ﬂush of leaves at irregular

intervals in a tuft at the top of the trunk. Thus, young plants

often have few leaves and offer little in terms of biomass. The

amount of biomass contained in the leaves of an older plant

may be signiﬁcantly higher, as cycad leaves tend to be per-

sistent, remaining on the plant for a long time.

As mentioned above, the leaves of the bennettitaleans were

shorter than those of modern cycads and would have thus

offered even less in terms of biomass. However, nothing is

known about the rate of growth in the bennettitaleans.

One cycad genus, Cycas, can reproduce itself vegetatively by

producing basal suckers, also known as bulbils or offsets, but

these also grow extremely slowly (Gee, pers. obs.). Other gen-

era, such as Encephalartos and Lepidozamia, have epicormic

buds in their trunks that will generate new growth if the plant

is damaged (Jones 1993).

As with most other extinct plant groups, nothing is known

about the potential for recovery and regrowth in the Ben-

nettiales.

Digestibility and Consumption by Modern

Herbivores and Humans

The fermentation experiments of Hummel et al. (2008)

show that cycad foliage is a poor producer of energy, vying

with the Podocarpaceae for the third-to-worst source of nutri-

tion for herbivores. Fermentation experiments could not be

run on the bennettitaleans because they do not have any liv-

ing relatives.

A major problem for herbivores feeding on cycads is the

presence of several strong toxins—macrozamin, cycasin, and

neocycasin, to mention a few—in various parts of the plants

(Hegnauer 1962). In Australia, the coordination of livestock

ingesting large quantities of the foliage or seeds of Bowenia,

Cycas, Lepidozamia, or Macrozamia becomes debilitated, and

the animals lose control of their hindlimbs (Jones 1993).

These ‘‘zamia staggers’’ happen mostly in cattle and sheep, but

also in horses, goats, and pigs. There are reports, however,

of some animals, namely emus, brush-tailed opossums, and

chuditch, that can ingest the seeds of Macrozamia riedlei,

gee

which contain high levels of macrozamin, without ill effects

(e.g., Ladd et al. 1993).

Despite the occurrence of these highly poisonous com-

pounds, humans have long learned to neutralize the toxicity

in cycad seeds by roasting or leaching in preparation for hu-

man consumption (Hegnauer 1962; Jones 1993). Australian

aboriginals, for example, began utilizing Cycas and Macro-

zamia as a food source at least 13,000 years ago (Jones 1993).

Both the starch-ﬁlled seeds and the large starch reserves in

the pith of the trunks, known as sago or arrowroot, are har-

vested for making small loaves, cakes, or porridge (Jones

1993). Moreover, the roots of three species of Zamia—Z. boli-

viana, Z. lecontei, and Z. ulei—are used in Brazil for medicinal

purposes as an antidote to snakebite (Hegnauer 1962).

It is not known whether the bennettitaleans and Mesozoic

cycads contained the same abundance and range of toxins as

the living cycads.

Co-occurrence with Major Late Jurassic

Sauropod Faunas

There is a wealth of cycadophyte leaves throughout the

Morrison Formation, from southern Utah to southern Canada

(Tidwell 1990b; Ash & Tidwell 1998). Pollen, on the other

hand, occurs in very small amounts—less than 1% of the en-

tire sporomorph ﬂora (Hotton & Baghai-Riding 2010)—and is

difﬁcult to distinguish from that of ginkgophytes. In Tenda-

guru, minor amounts of cycadophyte wood and cuticle have

been reported (Kahlert et al. 1999).

In Patagonia, both cycads and bennettitaleans were integral

parts of the Mesozoic ﬂora. In the Triassic, for example, cycado-

phytes are so common and rigorously constrained in their

stratigraphic occurrence that they can be used as biostrati-

graphic and chronostratigraphic markers (Spalletti et al. 1999;

Stipanicic 2002). Cycadophytes occur in the Early Jurassic but

are curiously absent in the Middle and Late Jurassic (Cúneo et

al. 2010), unlike elsewhere in the world, for example in the Late

Jurassic Morrison Formation, where they reach their climax. It

is instead in the Cretaceous when the cycadophytes reach their

peak of diversity and abundance in Patagonia, becoming ma-

jor components of the ﬂora (Cúneo et al. 2010). A recent study

testing possible co-evolution between herbivorous nonavian

dinosaurs and cycads in the Late Triassic and in the Cretaceous

found no signiﬁcant spatiotemporal correlation between these

two groups; nor did it ﬁnd any unequivocal support for co-

evolutionary interactions (Butler et al. 2009, 2010).

Remarks and Rating

On the bases of the paucity of leaves borne by most cycads

and bennettitaleans, as well as their slow growth and leaf re-

generation, potentially high toxin content, and low energy

yield, cycads and possibly also the bennettitaleans were a poor

dietary option for sauropods. Given the common occurrence

of cycadophytes in the Mesozoic landscape in both hemi-

spheres, a cycadophyte may have been offered an occasional

biteful of leaves when encountered by a herbivorous dinosaur,

but it is doubtful that they were truly a staple of their diet.

MESOZOIC SEED FERNS AND OTHER

ENIGMATIC GYMNOSPERMS

Seed ferns, also known as pteridosperms, are not a natural

group of plants but are lumped together on the basis of their

fern-like foliage and seed-bearing habit. Like Ginkgo and the

conifers, they are considered gymnosperms because their

seeds are unprotected by an ovary or fruit. Although seed ferns

such as Medullosa and Glossopteris are well known from the

Paleozoic, a completely different suite of seed ferns thrived

during the Late Paleozoic–Mesozoic. This included the Cay-

toniales, Corystospermales, Petriellales, and Peltaspermales

(Taylor et al. 2006). Other enigmatic Mesozoic gymnosperms

are the Gigantopteridales, Vojnovskyales, Iraniales, Pentox-

ylales, Czekanowskiales, and Hermanophytales (Taylor et al.

2009). Because they are extinct, there is no information on

seed ferns in regard to biomass production, regrowth, digest-

ibility, and consumption by modern herbivores; however,

four of these orders—the Caytoniales, Corystospermales,

Czekanowskiales, and Hermanophytales—will be discussed

brieﬂy here as a reminder that Mesozoic seed ferns also likely

formed a part of the sauropod diet.

Habit and Habitat

The Caytonia plant that bore the palmately compound

leaves of Sagenopteris may have been part of swamp vegetation

during Early Cretaceous times because it is associated with

lignites in the Kootenai Formation in Montana, which over-

lies the Late Jurassic Morrison Formation (LaPasha & Miller

1984). The Corystospermales, which grew primarily in Gond-

wana, were probably small to large woody shrubs (Taylor et al.

2009), although some of them may have been medium-sized,

unbranched, tree fern-like plants, or even had a scrambling

habit (Taylor et al. 2006).

The existence of the Czekanowskiales is known through

their leaves. Virtually nothing is known of growth forms in

this group, although some information on habitat preference

can be inferred from the fossil record. Czekanowskialean re-

mains occur with coals and ﬂoras rich in hydrophilic plants,

such as Equisetum and ferns, in the Morrison Formation and

elsewhere in the world, and suggest that Czekanowskia grew

under humid, temperate to tropical conditions (Ash 1994;

Tidwell 1990b; Ash & Tidwell 1998; Tidwell et al. 1998 and

references therein).

The Hermanophytales are an enigmatic group characterized

by permineralized stems with internal wedges of secondary

xylem (wood). Hermanophyton trunks range from 3 to 22.5 cm

Dietary Options for the Sauropod Dinosaurs 49

in diameter, measure over 18 m in length, and currently are

known from only four sites in the Morrison Formation (Ar-

nold 1962; Tidwell & Ash 1990; Tidwell 1990b, 2002; Ash &

Tidwell 1998). In regard to habit, it is thought that Herma-

tophyton may represent a small- to medium-sized, narrow-

stemmed tree with a crown of small leaves, or a long liana

(Taylor et al. 2009).

Co-occurrence with Major Late Jurassic

Sauropod Faunas

Three of the orders of seed ferns under discussion here have

been found in the Morrison Formation. The foliage of Cay-

tonia—represented by the form genus Sagenopteris—occurs in

the northern part of the Morrison Formation, in Belt, Mon-

tana (Brown 1972), as well as in the Early Cretaceous Kootenai

Formation in Montana (LaPasha & Miller 1985) and western

Canada (Bell 1956) which overlies the Morrison Formation.

Both Czekanowskia and Hermatophyton have been described

from several sites from the Morrison Formation (Ash 1994;

Tidwell 2002). The bisaccate pollen of the Caytoniales (Vitrei-

sporites type) and Czekanowskiales (Alisporites type) are also

represented in the Morrison Formation (Litwin et al. 1998;

Hotton & Baghai-Riding 2010).

At Tendaguru, bisaccate pollen of Alisporites that could per-

tain to the Corystospermales has been reported (Schrank 1999,

2010). However, fossil remains of the Caytoniales, Czekanow-

skiales, and Hermanophytales have not been found.

Within the region consisting of southern South America

and the nearby Antarctic Peninsula, Sagenopteris leaﬂets per-

taining to the Caytoniales have been described from the Ju-

rassic of Antarctica (Halle 1913; Gee 1989; Cantrill 2000),

although they have not been reported from Patagonia. How-

ever, as was mentioned earlier, the corystosperms were a major

element of the understory in Triassic forests of Patagonia,

alongside the bennettitaleans (Artabe et al. 2001; Cúneo et al.,

2010). Neither the Czekanowskiales nor the Hermanophytales

are known from Patagonia.

Remarks and Rating

Because Mesozoic seed ferns and other enigmatic gymno-

sperms were a distinctive component of Mesozoic ﬂoras, they

should not be overlooked in surveys of the Mesozoic ﬂora.

However, because little is known about their palatability, nu-

tritional value, and ability to regrow after herbivory, it is difﬁ-

cult to evaluate their potential as a dietary option. They may

have played at least a minor role in the diets of large sauro-

pods, especially if they grew in more open areas.

Discussion

As summarized in this chapter, a number of different variables

have been taken into account in the evaluation of plants as

sauropod fodder. Central to this discussion is the availability of

the individual plant groups to a large sauropod, which is re-

ﬂected in part in the plant’s habit (growth form) and habitat

(environment in which it is found). Trees have the general

advantage of being able to offer more leaf biomass on their

spreading branches than smaller herbaceous plants such as

ferns. One exception is Equisetum; although herbaceous and

usually small in stature, horsetails have a fast growth rate and a

dense, colony-forming habit that boost their productivity and

biomass. In regard to habitat, plants that grew in more open

areas and not in dense forests would have theoretically been

more accessible to the larger sauropods, which would have had

problems maneuvering in tight spaces. Continuing this line of

thought, large conifers growing as solitary trees in open habi-

tats, in lightly wooded areas, or at the edge of a dense forest

would have been the most accessible to large sauropods.

Factors such as biomass production (growth rate) and po-

tential for recovery (regrowth of eaten plant parts) are also

important issues when assessing good long-term food sources.

Plants with low biomass production and low potential for re-

covery, such as the cycads and most ferns, are less likely to

serve as recurring food sources than plants with high biomass

production and greater potential for recovery. Examples of the

latter group include Equisetum, ginkgophytes, and conifers.

In this study, the potential for recovery not only means the

simple replacement of browsed plant parts, but also includes

the longevity of individual plants and taxa through geologic

time. To this end, it should be noted that a number of nearest

living relatives of the Mesozoic ﬂora have dormant basal and/

or aerial buds that will grow and replace roots, stems, and

branches in the face of injury. This includes all of the living

gymnosperms under study here: Ginkgo, the Araucariaceae,

Podocarpaceae, Cupressaceae, and Pinaceae, and even the

cycads.

Whether these dormant buds are called epicormic buds, cop-

pice shoots, aerial chichi, basal chichi, lignotubers, or burls,

woody plants with such dormant buds are known as sprouters

in the ecological literature and are common in both temperate

and tropical forests. The sprouting response leads to long-lived

individuals with long generation times that will preserve ge-

netic diversity, even in small populations (Bond & Midgley

2001). This is certainly the case in the living fossil Ginkgo and in

most of the conifer taxa discussed in this chapter.

Sprouters are resistant to disturbances and catastrophes

such as those caused by ﬁre, hurricane damage, drought,

ﬂooding, landslides, and herbivory (Bond & Midgley 2001).

Indeed, in modern ecosystems, it is thought that ‘‘sprouting

behavior might also be important in determining tree species

survival in the face of browsing by heavy mammals’’ (Bond &

Midgley 2001, p. 49). In this case, reference was being made to

the many species of savanna trees of a coppice in response

to damage caused by the largest herbivores on earth today, the

gee

elephants. Assuming that sauropods fed on foliage, twigs, and

branches, and that they may have damaged tree trunks, bark,

and roots in their wake, being able to recover, regrow, and

resprout would have been advantageous for woody plants

during the Mesozoic.

Digestibility, which is quantiﬁed in the in vitro fermenta-

tion experiments of Hummel et al. (2008), and palatability,

which is reﬂected in part in the consumption of plant groups

by modern herbivores, are two more key factors. Although the

fermentation experiments were designed to reﬂect herbivore

hindgut digestion in general (Hummel & Clauss, this vol-

ume), the palatability of certain plants appears to be depen-

dent on the herbivore, as evidenced by the survey presented in

this chapter.

Most plant groups in this survey do co-occur with sauropods

in the areal extent of the three major sauropod faunas of the

Late Jurassic, which indicates that there were indeed opportu-

nities for herbivore–plant interactions at many sites. On the

basis of this brief review of co-occurrences, the most common

food options available in the Western Interior of North Amer-

ica (Morrison Formation), eastern Africa (Tendaguru), and

southern South America (Patagonia) would have been trees of

the Cheirolepidiaceae, Araucariaceae, and Podocarpaceae.

Comparative Rating of Plant Groups

By taking an integrated botanical and paleobotanical ap-

proach, it is clear that several plant groups would have been

good, accessible sources of food to the large sauropods in the

Mesozoic. Leading would be plants such as Equisetum, Arau-

caria, and the Cheirolepidiaceae, which were common in

Mesozoic ecosystems around the world and could offer much

biomass as fodder. These plants grew in thick stands around

freshwater (Equisetum) or brackish (Cheirolepidiaceae) bodies

of water, or as large trees in open forests (Araucaria, Cheiro-

lepidiaceae). Additional features attractive to sauropods may

have been the high energy content of Equisetum shoots and

rhizome tips, the unusual fermentation behavior of Araucaria

that yields more energy when retained in the hindgut for

longer periods of time (e.g., more than 30 hours), and the

succulence of the leaves of the Cheirolepidiaceae.

Although limited to the Northern Hemisphere, ginkgoes

may have been a good source of energy and especially pro-

tein. Similarly, conifers such as the Podocarpaceae and Cu-

pressaceae—and the Pinaceae to a lesser extent, due to their

Northern Hemisphere distribution—were convenient sources

of fodder, providing much biomass but fewer kilojoules per

mouthful than those plants mentioned above.

Because of their generally smaller stature and need for moist,

humid conditions such as those found in dense, closed forests,

most ferns would have been difﬁcult for large sauropods to

encounter and ingest regularly. This would have included

Table 3.1. Likeliness of Mesozoic Plant Groups as a

Preferred Food Source for the Sauropod Dinosaurs

Plant group Rating Likeliness as a food source

Araucaria, Equisetum,

Cheirolepidiaceae

***** Very likely

Ginkgo **** Rather likely

Other conifer families

(e.g., Podocarpaceae,

Cupressaceae, Pinaceae)

*** Moderately likely

Ferns (e.g., Angiopteris,

Osmunda)

** Less likely

Cycads and

bennettitaleans

* Least likely

Seed ferns, other

enigmatic gymnosperms

Unknown Cannot be evaluated at

this time

Angiopteris and Osmunda, which are excellent sources of energy

today. Fast-growing ferns that were better adapted to more

open areas under mesic conditions would have had to occur in

great abundance (the ‘‘fern prairies’’ of Taggart & Cross 1997,

for example) for a sauropod to make a meal of low-biomass

fronds of individual ferns.

Cycads were probably last on the list of desirable food op-

tions as a result of their low energy yield, low biomass produc-

tion, extremely slow growth rates, and high content of toxins.

However, because cycads (and bennettitaleans) were common

plants in open areas, sauropods may have occasionally in-

cluded them in their diet as well.

These plant groups can be compared to one another in re-

gard to their likelihood as a preferred dietary option or com-

monly eaten source of food for the large sauropod dinosaurs

(Table 3.1). Hence, taxa with ﬁve stars in Table 3.1 were most

likely to have been an accessible, dependable, plentiful, and

energy-producing food, while those with one star were the

least attractive as a food source. The relative ranking given in

Table 3.1 is offered as a baseline for future reﬁnement and

discussion.

Conclusions

This survey of the Mesozoic ﬂora, which took into account

plant habit, habitat, biomass production, potential for recov-

ery, digestibility, consumption by modern herbivores, and co-

occurrence with sauropods in the Late Jurassic, revealed that

some plant groups were likely a more accessible, sustaining,

or preferred source of nutrition for the sauropod dinosaurs.

This included Araucaria, Equisetum, the Cheirolepidiaceae,

and Ginkgo. Sauropods were only moderately likely to browse

Dietary Options for the Sauropod Dinosaurs 51

other conifers, such as the Podocarpaceae, Cupressaceae, and

Pinaceae, and less likely to feed on forest-dwelling ferns such

as Angiopteris and Osmunda. The least likely eaten plants may

have been the cycads and bennettitaleans.

Acknowledgments

Sincere thanks are due to my colleagues in the DFG Research

Unit 533 for their helpful discussions, especially Martin Sander,

Jürgen Hummel (both at the University of Bonn), and Marcus

Clauss (University of Zurich), as well as to reviewers Bill Chal-

oner (University College London) and Jim Farlow (Purdue

University, Fort Wayne, Indiana) for their cogent remarks and

corrections. I am also indebted to Kerry Hanrahan (Atherton

Forestry Ofﬁce, Forestry Plantations Queensland) for an

extensive, all-day tour through the Araucaria plantations and

to David Warmington (Cairns Botanic Garden, Cairns) for or-

ganizing a trip to see the northernmost natural population of

Araucaria bidwillii in northern Queensland, as well as to Hans

Hagdorn (Muschelkalkmuseum Ingelﬁngen) and Ted Delevor-

yas (University of Texas at Austin) for the use of their photos

of Osmunda and Cycadeoidea, respectively. This is contribu-

tion number 62 of the DFG Research Unit 533 ‘‘Biology of the

Sauropod Dinosaurs: The Evolution of Gigantism.’’

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Digestibility of dinosaur food plants revisited and expanded: Previous data, new taxa, microbe donors, foliage maturity, and seasonality

Article

Full-text available

Dec 2023
PLOS ONE

Although the living relatives of the Mesozoic flora were once assumed to constitute a nutritionally poor diet for dinosaur herbivores, in vitro fermentation of their foliage has shown that gymnosperms, ferns, and fern relatives can be as highly digestible as angiosperm grasses and dicots. Because nutritional information cannot be preserved in the fossil record, this laboratory approach, first published in 2008, provides a novel alternative to evaluate the digestive quality of the plants that were available to dinosaur megaherbivores such as sauropods. However, very few further studies have since been conducted to supplement and confirm the high fermentative capacity of nonangiospermous taxa. Here we show that the living relatives of the Araucariaceae and Equistaceae are consistently highly digestible, even between taxa and when influenced by environmental and biological factors, while fern taxa are inconsistent on the family level. These results reinforce previous findings about the high energetic potential of Jurassic-age plant families. Fourteen species of fern and gymnosperm foliage from five Jurassic families were collected in the spring and fall, then analyzed for their digestibility using the in vitro Hohenheim gas test. Equisetum, Araucaria, and Angiopteris were the most digestible genera in both seasons, while Agathis, Wollemia, and Marattia were the least digestible. The season in which specimens were collected was found to have to a significant effect on gas production in four out of 16 samples (P < 0.05). Furthermore, leaf maturity influences digestibility in Marattia attenuata (P < 0.05), yet not in Cyathea cooperi (P = 0.24). Finally, the species of the rumen fluid donor did not influence digestibility (P = 0.74). With the original data set supplemented by one new genus and four species, this study confirms and expands previous results about the nutritional capacity of the living relatives of the Jurassic flora.

Palynological reconstruction of the habitat and diet of Iguanodon bernissartensis in the Lower Cretaceous Morella Formation, NE Iberian Peninsula

Article

Full-text available

Apr 2024
CRETACEOUS RES

The recent discovery of iguanodontid remains from the new Palau-3 site in the Lower Cretaceous Morella Formation is the most complete non-articulated skeleton of Iguanodon bernissartensis on the NE Iberian Peninsula. To elucidate the paleoenvironment of the Palau-3 site, a palynological analysis was carried out on matrix samples collected from around the skeleton. The palynological assemblage is found to correspond to an upper Barremian age. While the assemblage is composed of bryophytes, pteridophytes, gymnosperms, freshwater algae, dinoflagellate cysts and fungal spores, the palynoflora is mostly dominated by the Cheirolepidiaceae conifer (Classopollis) and Anemiaceae fern (mainly Cicatricosisporites) families. The absence of angiosperm pollen in this flora is also noteworthy, as angiosperm remains have been recorded previously elsewhere in the Morella Formation. At the Palau-3 site, the fronds of Cyatheaceae and Anemiaceae ferns, as well as the foliage of the Cheirolepidiaceae conifers, may have been the major sources of nutrition of I. bernissartensis and other herbivorous iguanodontians. The paleobotany of the four major localities bearing I. bernissartensis remains in western Europe was surveyed to determine the habitat and feeding preferences of this styracosternan dinosaur. These localities are Bernissart (Belgium), Isle of Wight (England), Nehden (Germany), and Morella (Spain). In accordance to this survey, the habitat preferences of I. bernissartensis and association with specific plant communities show that this ornithopod species was adapted to a wide variety of paleoenvironments.

The Albian vegetation of central Alberta as a food source for the nodosaurid Borealopelta markmitchelli

Article

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Dec 2022
PALAEOGEOGR PALAEOCL

During the Cretaceous, large herbivorous dinosaurs (megaherbivores) acted as keystone species—just as large mammals do today (e.g., elephants)—yet despite their significance in Cretaceous ecosystems, what plant taxa these dinosaurs ate is unclear. The Albian armoured dinosaur Borealopelta markmitchelli (Ornithischia; Nodosauridae) was discovered in northern Alberta, Canada and has well-preserved stomach contents dominated by fern leaf tissues, with low amounts of gymnosperm material, implying selective feeding. The lower Albian Gates Formation (Grande Cache Member) macroflora of central Alberta is contemporaneous and spatially proximal with B. markmitchelli and therefore provides information on local vegetation available to this nodosaurid and other megaherbivores in this area. In this study we provide census-sampled abundance data for the Gates Formation macroflora. These data also provide the means to further investigate the feeding ecology of Borealopelta by summarizing the vegetation and local food options available. Census collections at five sites within the Grande Cache Member exposed in the Grande Cache Coal Mine reveal that the local vegetation there was dominated by conifers (44–70%) across all sites. Athrotaxites, Elatides, and Pityocladus were the most common conifers. Other gymnosperms present were ginkgophytes (e.g., Ginkgoites; 11%) and Taeniopteris (9%). Caytoniales (Sagenopteris) were found at one study site but uncommon (2%). Ferns (e.g., Cladophlebis, Coniopteris, Gleichenites) accounted for 14% of the total site counts while cycadophytes (Bennettitales; 4%) and Equisetites (1%) were less common. When comparing the Gates Formation macroflora to the stomach contents of Borealopelta, these data suggest that B. markmitchelli was selectively feeding on ferns, or in a recently disturbed fern-dense area within the local landscape.

The dentition of the Late Jurassic dwarf sauropod Europasaurus holgeri from northern Germany: ontogeny, function, and implications for a rhamphotheca-like structure in Sauropoda

Article

Full-text available

Aug 2024

The basal macronarian sauropod Europasaurus holgeri is known only from the Late Jurassic of the Langenberg Quarry near Goslar, Lower Saxony, Germany. Europasaurus has been identified as an insular dwarf and shows a clear resemblance to Camarasaurus and Giraffatitan . This study provides a detailed description of the dentition of Europasaurus based on an array of fossils outstanding in their abundance, variety of preservation, and ontogenetic range. Dental morphology for the replacement and functional dentitions, the tooth replacement pattern, and implications for food intake are described for the Europasaurus dentition, which is characterized by broad-crowned teeth. Characteristic features for Europasaurus are the presence of denticles on replacement teeth, the wrinkled enamel, and large wear facets both on the apex and on the carinae of the tooth crowns. The partially articulated skull SNHM-2207-R and isolated tooth rows DfmMh/FV 580.1 and DfmMh/FV 896.7 suggest the presence of strong connective tissue partially covering the teeth. This connective tissue would have provided stability and protection for the teeth. Evidence for this connective tissue include exposed tooth necks, in-situ teeth with strongly resorbed roots which no longer would have been connected to the jaw bone, and wrinkled enamel and its surface pattern. The same features can be observed in other sauropod taxa as well. We therefore suggest that eusauropods in general possessed this connective tissue structure, which may be an autapomorphy of the group. Possibly, this hypothetical structure is homologous to the rhamphotheca in birds and some non-avian theropods, which, however rarely, show such a close integration of keratinous tissue and teeth that we hypothesize here.

The first record of sauropod dinosaurs from a palaeotopographical upland environment and its implications for megaherbivorous dinosaur faunal turnover in the Early Cretaceous of northwestern Europe

Article

Full-text available

Mar 2023

fragmentary centrum of a dorsal vertebra and a manual ungual phalanx of eusauropod dinosaurs from the Upper Barremian – Lower Aptian of Balve in western Germany are described. The dorsal centrum shares potential synapomorphies with the enigmatic genus Ornithopsis and can probably be referred to a titanosauriform. The Balve record is of significance as it represents the only known direct evidence of this clade from an upland environment in Europe, which is assumed to have reached palaeoelevations of several hundred meters above sea level. Taphonomic signatures at some of the material from this site indicate prolonged surface exposure plus various stages of wear caused by water transport. The remains were finally deposited in sediment traps within a karst cave or fissure system. The fossil record suggests a retreat or shift of sauropod habitat range from coastal plains and lowlands to hinter- and uplands during the Early Cretaceous in northwest Europe. It is hypothesized that this was linked to the faunal replacement of low- and mid-level browsing sauropods (e.g. diplodocoideans) by iguanodontian ornithopods near the Jurassic-Cretaceous boundary in this region. High-browsing titanosauriform sauropods had small overlap in the trophic niche with the ornithopods, facilitating a sympatric coexistence of both groups. However, their range was dependent on highcanopy vegetation that was probably more abundant in uplands. The previously observed “mid-Cretaceous bottleneck” in sauropod diversity may therefore be a result of partial extinction and/or a sampling bias, as the preservation of upland faunas are very exceptional. However, it is be cautioned to interpolate these regional observations to global sauropod diversity patterns.

Two-seeded cones of probable gnetalean affinity from the Morrison Formation (Late Jurassic) of Utah and Colorado, USA

Article

Dec 2022

Three dimensional calcitic casts of a two-seeded compound cone are described from the Upper Jurassic Brushy Basin Member of the Morrison Formation based on specimens from Colorado and Utah. Cones of Bassitheca hoodiorum gen. et sp. nov. are broadly obovate in face view, ~3.5 mm high, ~2.6 mm wide, and viewed from above have two planes of symmetry. Micro-CT scanning of numerous specimens shows that each cone has two well-developed orthotropous seeds positioned opposite each other in the major plane and separated by a median longitudinal septum in the minor plane. At a higher level in the cone, a median apical septum in the major plane separates two depressions arranged opposite each other. The two well-developed seeds in the major plane are enclosed by bracts, but numerous incomplete cones, together with cones showing lines of dehiscence, indicate that each seed was shed by the abscission of a lateral valve. One specimen indicates that three vascular bundles entered the base of each well-developed seed and these are interpreted as the vascular supply to the envelope of a chlamydospermous ovule. The opposite and decussate arrangement of bracts at the base of the cone, the paired arrangement of the two well-developed seeds perpendicular to the two apical depressions, combined with the inferred seed envelope that was apparently shed with the seed, indicates a probable relationship to Gnetales and specifically to extant Ephedra . Along with Dayvaultia tetragona Manchester et Crane, also known from the Brushy Basin Member of the Morrison Formation, Bassitheca hoodiorum provides further evidence that the Gnetales were more significant in the Morrison vegetation than has been recognized previously.

Multi-proxy dentition analyses reveal niche partitioning between sympatric herbivorous dinosaurs

Article

Full-text available

Dec 2022

Dentitions of the sympatric herbivorous dinosaurs Hungarosaurus (Ankylosauria, Nodosauridae) and Mochlodon (Ornithopoda, Rhabdodontidae) (Santonian, Hungary) were analysed to investigate their dietary ecology, using several complementary methods—orientation patch count, tooth replacement rate, macrowear, tooth wear rate, traditional microwear, and dental microwear texture analysis (DMTA). Tooth formation time is similar in Hungarosaurus and Mochlodon, and traditional and DMTA microwear features suggest low-browsing habits for both taxa, consistent with their inferred stances and body sizes. However, Mochlodon possesses a novel adaptation for increasing dental durability: the dentine on the working side of the crown is double the thickness of that on the balancing side. Moreover, crown morphology, enamel thickness, macrowear orientation, and wear rate differ greatly between the two taxa. Consequently, these sympatric herbivores probably exploited plants of different toughness, implying dietary selectivity and niche partitioning. Hungarosaurus is inferred to have eaten softer vegetation, whereas Mochlodon likely fed on tougher material. Compared to the much heavier, quadrupedal Hungarosaurus, the bipedal Mochlodon wore down more than twice as much of its crown volume during the functional life of the tooth. This heavy tooth wear might correlate with more intensive food processing and, in turn, could reflect differences in the metabolic requirements of these animals.

Biological Evolutionary Lineages in Terrestrial Habitats in the Phanerozoic

Chapter

Aug 2024

Markus Knoflacher

Abiotic framework conditions of terrestrial evolution are quite different from aquatic habitats. Low density of air reduces the impacts of air currents and dampens to much lower extents the impacts of gravity, solar radiation and temperature dynamics than water. Dynamics of temperature and precipitations are essential constraints for the dispersal of photoautotrophic organisms on land. Erosion of land surfaces is challenging for the reconstruction of terrestrial evolution over the Earth history—in particular for microbial life forms. For multicellular terrestrial evolution are land plants in interactions with fungi and microorganisms pivotal. Land plants provided not only organic material for heterotrophic organisms but modified also—within their eco-physiological potentials—hydrogeological processes and climatic conditions. Dispersal of land plants stimulated the emigrations of some animals groups from sea to land. Invertebrates migrated at first over different routes into terrestrial habitats. Evolutionary adaptations of mouthparts and gut microbiomes—in particular of arthropods—to overcome resistant living tissues of land plants extended the energetic basis for herbivores. Vertebrates followed as fishes into freshwater habitats and—after modifications of hydro-geodynamics by deep rooting plants—eventually as tetrapods into terrestrial habitats. Asynchronous terrestrialisation of plants and animals induced global long-term adaptive damped oscillating processes with at least three phases indicating heterarchic interdependencies in evolutionary processes. The first phase can be characterised by expansions of land plants without constraints of large herbivores, the second by diversification of large vertebrate herbivores and the third by increasing interdependencies between plants (angiosperms) and animals (insects). Framework conditions of the third phase were essential for evolution of the genus Homo—now the biggest biological risk factor for global mass extinctions.

Multiproxy palaeoenvironmental reconstruction of the Bathonian Castelbouc sauropod tracksite (Causses Basin, southern France): Insight into a Middle Jurassic insular ecosystem

Article

Apr 2024
Geobios

We report lignitic fossil rich-beds from the Bathonian Castelbouc sauropod tracksite (Castelbouc Cave N �4, Causses Basin, southern France). Showing the co-occurrence of amber with plant, vertebrate and invertebrate remains, they are a precious tool to reconstruct Middle Jurassic dinosaur ecosystems. A multiproxy approach combining sedimentology, petrology, mineralogy and palaeontology led to determine that these fossil rich-beds were deposited in a range of insular coastal palaeoenvironments. They include protected backshore areas such as freshwater/brackish ponds and brackish bay/lagoon showing cooccurrence of terrestrial and marine inputs. The backshore environments were particularly rich in ostracods (Darwinula sp., Fabanella bathonica) and gyrogonites of charophytes (Porochara douzensis). The abundance of conifer remains including leafy axes (Brachyphyllum), cones (cf. Classostrobus), wood (Brachyoxylon) and pollen grains (Classopollis) shows that ponds and bay/lagoon were bordered by conifer-dominated forests in which Cheirolepidiaceae were the main component. Such a rich and relatively diverse flora was probably an attractive source of food for megaherbivorous dinosaurs. Vertebrate microremains mostly consist of fish scales (Ginglymodi indet.) and crocodylomorph teeth (Atoposauridae indet.), two groups that are common components of Middle Jurassic paralic faunas. The palaeobotanical assemblage suggests a warm subtropical climate probably tropophilous with marked alternation between a wet and a dry season.

Expanding the diversity of conifer xyloflora from Early Cretaceous Crato Fossil Lagerstätte, Brazil

Article

Mar 2024
REV PALAEOBOT PALYNO

Biozonación paleoflorística y cronoestratigrafidotlessa del Triásico argentino

Article

Full-text available

Jan 1999

Palaeoecology and depositional environments of the Tendaguru Beds (Late Jurassic to Early Cretaceous, Tanzania)

Article

Full-text available

Jan 2002

The Late Jurassic to Early Cretaceous Tendaguru Beds (Tanzania, East Africa) have been well known for nearly a century for their diverse dinosaur assemblages. Here, we present sedimentological and palaeontological data collected by the German-Tanzanian Tendaguru Expedition 2000 in an attempt to reconstruct the palaeo-ecosystems of the Tendaguru Beds at their type locality. Our reconstructions are based on sedimentological data and on a palaeoecological analysis of macroinvertebrates, microvertebrates, plant fossils and microfossils (ostracods, foraminifera, charophytes, palynomorphs). In addition, we included data from previous expeditions, particularly those on the dinosaur assemblages. The environmental model of the Tendaguru Beds presented herein comprises three broad palaeoenvironmental units in a marginal marine setting: (1) Lagoon-like, shallow marine environments above fair weather wave base and with evidence of tides and storms. These formed behind barriers such as ooid bar and siliciclastic sand bar complexes and were generally subject to minor salinity fluctuations. (2) Extended tidal flats and low-relief coastal plains. These include low-energy, brackish coastal lakes and ponds as well as pools and small fluvial channels of coastal plains in which the large dinosaurs were buried. Since these environments apparently were, at best, poorly vegetated, the main feeding grounds of giant sauropods must have been elsewhere. Presumably, tidal flats and coastal plains were visited by dinosaurs primarily during periods of drought. (3) Vegetated hinterland. Vegetation of this environment can only be inferred indirectly from plant material transported into the other depositional environments. Vegetation was dominated by a diverse conifer flora, which apparently formed part of the food source of large herbivorous sauropods. Evidence from various sources suggests a subtropical to tropical palaeoclimate, characterised by seasonal rainfall alternating with a pronounced dry season during the Late Jurassic. In Early Cretaceous times, sedimentological and palaeontological proxies suggest a climatic shift towards more humid conditions. Die Tendaguru-Schichten von Tansania in Ostafrika (Oberjura bis Unterkreide) sind als Lagerstätte oberjurassischer Dinosaurier seit nahezu einem Jahrhundert weltweit bekannt. Anhand von sedimentologischen und paläontologischen Daten, die während der Deutsch-Tansanischen Tendaguru Expedition 2000 im Typus-Gebiet der Tendaguru-Schichten gewonnen wurden, werden Paläo-Ökosysteme rekonstruiert. Grundlage der Rekonstruktionen sind die Auswertung sedimentologischer Daten sowie die paläo-ökologische Analyse von Makroinvertebraten, Mikrovertebraten, pflanzlichen Fossilien und Mikrofossilien (Ostrakoden, Foraminiferen, Charophyten, Palynomorphen). Darüber hinaus werden Informationen über Dinosaurier berücksichtigt, die bei früheren Expeditionen gewonnen wurden. Das hier vorgestellte Ablagerungsmodell der Tendaguru-Schichten umfaßt drei Teilbereiche eines randlich marinen Sedimentationsraumes, die wie folgt gekennzeichnet werden können: (1) Lagunen-artige, marine Flachwasserbereiche, die oberhalb der Schönwetter-Wellenbasis lagen und unter deutlichem Einfluß von Gezeiten und Stürmen standen. Sie waren vom offenen Meer durch Barrieren, wie Ooidbarren und siliziklastischen Sandbarrenkomplexen, getrennt und wiesen einen leicht schwankenden Salzgehalt auf. (2) Ausgedehnte Wattgebiete und flache Küstenebenen. Dort befanden sich niedrig-energetische, brackische Strandseen und Teiche sowie Tümpel und kleinere Flußrinnen, in denen die großen Dinosaurier eingebettet wurden. Da diese Lebensräume bestenfalls dürftig bewachsen waren, müssen die Nahrungsquellen und der eigentliche Lebensraum der riesigen Sauropoden anderswo gelegen haben. Vermutlich wurden die Wattgebiete und Flachküsten von Dinosauriern vorrangig in den Trockenzeiten aufgesucht. (3) Bewachsenes Hinterland. Die Vegetation dieses Lebensraumes kann nur indirekt aus Pflanzenresten erschlossen werden, die in die anderen Ablagerungsraume transportiert wurden. Die Vegetation wurde von einer diversen Koniferenflora dominiert, die zumindest teilweise die Nahrungsgrundlage der großen, herbivoren Sauropoden bildete. Sedimentologische und paläontologische Indikatoren sprechen für ein subtropisches bis tropisches Klima wahrend der späten Jurazeit mit einem jahreszeitlichen Wechsel von Regenfällen und ausgeprägten Trockenzeiten. In der frühen Kreidezeit deutet sich ein Wechsel zu starker humiden Bedingungen an. doi:10.1002/mmng.20020050103

Ecology of the Southern Conifers

Article

Full-text available

Jan 1995

Why were dinosaurs so large? A food quality hypothesis

Article

Full-text available

Nov 2002
EVOL ECOL RES

Some dinosaurs, notably the sauropods, were the largest of all land animals, present or past. There is no generally agreed reason for this gigantism. We question the recent suggestion that this was due to high productivity, from high CO2 concentrations, at the time of the dinosaurs. Instead, we suggest the reason for this large size was because typical Jurassic/Triassic plants, such as cycads and conifers, were of inherently low food quality (low nitrogen concentration). High CO2 at the time of the dinosaurs would have resulted in an even lower food quality. Present-day megaherbivores are associated with relatively low-quality food-plants and we suggest this applied to sauropods.

Marattia aganzhenensis sp. nov. from the Lower Jurassic Daxigou Formation of Lanzhou, Gansu, China

Article

Feb 2008

Marattia aganzhenensis sp. nov. from the Lower Jurassic Daxigou Formation of Lanzhou, Gansu, China, is the second species of Marattia known in fertile structure from China, in addition to Marattia asiatica. The new species demonstrates the variability of the genus through its distinct character states. This new species is distinguished by the absence of venuli recurrentes, the shorter synangia, exclusively monolete spores without surface ornamen- tation, and the low number of spores produced per sporangium. Keywords: China, Gansu, Lower Jurassic, Marattia aganzhenensis sp. nov., Marattiales.

Palynology of the dinosaur beds of Tendaguru (Tanzania) — preliminary results

Article

Jan 1999

Eckart Schrank

The Tendaguru Beds, southeastern Tanzania, have yielded two palynological assemblages of Kimmeridgian to Tithonian age: (1) the Anapiculatisporites-Densoisporites-Trisaccites assemblage from the Middle Saurian Beds and (2) the Barbatacysta-Pareodinia assemblage from the overlying Smeei Beds. A third assemblage with Rhizophagites and rare angiosperm pollen from the Upper Saurian Beds is contaminated by recent and subrecent material. The Anapiculatisporites-Densoisporites-Trisaccites assemblage is characterized by the presence of freshwater algae (Ovoidites), pteridopyhtic-bryophytic spores and gymnosperm (conifer) pollen, with Classopollis as the most abundant element. Among the rare elements of this assemblage is the questionable dinoflagellate Mendicodinium? quadratum, possibly a Kimmeridgian-Tithonian marker. The miospores show palaeobiogeographic links to Southern Gondwana, especially Madagascar, Australia, Argentina and India. Deposition of this assemblage took place in an aquatic environment with strong palynological influx from a terrestrial source and questionable marine influence. The Barbatacysta-Pareodinia assemblage contains a considerable number of dinoflagellates suggesting deposition in a marine environment. The terrestrially-derived miospores are impoverished and dominated by conifer pollen, while pteridophytic-bryophytic spores form a very subordinate element or are absent. Die Tendaguru-Schichten, Südost-Tansania, haben zwei palynologische Assoziationen, deren Alter als Kimmeridge bis Tithon interpretiert wird, geliefert. Die Anapiculatisporites-Densoisporites-Trisaccites-Assoziation stammt aus den Mittleren Saurierschichten, und die Barbatacysta-Pareodinia-Assoziation charakterisiert die darüberlagernden Smeei-Schichten. Eine dritte Vergesellschaftung mit Rhizophagites und seltenen Angiospermen-Pollen aus den Oberen Saurierschichten ist durch rezentes bis subrezentes Material kontaminiert. Die Anapiculatisporites-Densoisporites-Trisaccites-Assoziation ist durch die Anwesenheit von Süßwasser-Algen (Ovoidites), Pteridophyten-Bryophyten-Sporen und Gymnospermen-Pollen (Koniferen) gekennzeichnet mit Classopollis als dem häufigsten Element. Zu den seltenen Elementen dieser Assoziation gehört der fragliche Dinoflagellat Mendicodinium? quadratum, der möglicherweise als leitend für das Kimmeridge-Tithon angesehen werden kann. Die Miosporen zeigen paläobiogeographische Verbindungen nach Südgondwana, besonders nach Madagaskar, Australien, Argentinien und Indien. Das Ablagerungsmilieu dieser Assoziation war aquatisch mit starker Zufuhr von terrigenem Material, während mariner Einfluß fraglich ist. Die Dinoflagellaten-führende Barbatacysta-Pareodinia-Assoziation wurde in einem marinen Milieu gebildet, in dem die Zufuhr terrigener Palynomorphe reduziert und im wesentlichen auf Koniferen-Pollen beschränkt war, während Pteridophyten-Bryophyten-Sporen nur sehr untergeordnet vorkommen oder ganz fehlen. doi:10.1002/mmng.1999.4860020113

Palynological evidence on the age of the Morrison Formation, Western Interior U.S

Article

Jan 1998

Paleoecología de las floras triásicas argentinas

Article

Jan 2001

Primary Production of the Major Vegetation Units of the World

Chapter

Jan 1975

Helmut Lieth

The primary productivity of the world is of paramount importance for man. Primary productivity captures that portion of solar energy that supports the life of all components of the biosphere. The largest portion of human food is provided by the productivity of plant life on land. From land production also comes our greatest single substance for construction and fabrication—wood—and a host of other products. The productivity of vegetation is one major aspect (the accumulation of toxic materials in the environment and potential psychologic effects are others) of the carrying capacity of the earth for man—its ability to support human populations on a long-term basis. Fossil fuels are accumulated profits from past primary production. The mantle of vegetation protects the Earth’s surface against destructive erosion; and it provides an important part of the environmental context in which man and his societies have developed and in which man himself feels most at home. It is by primary productivity and the growth of plants by the creation of organic matter through photosynthesis that the life of the vegetational mantle and thereby of man is maintained.

On the Upper Jurassic stem Hermanophyton and its species from Colorado and Utah, USA

Article

Jan 1990

Dietary options for the sauropod dinosaurs from an integrated botanical and paleobotanical perspective

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