Historical Biology

Published by Taylor & Francis
Online ISSN: 0891-2963
Publications
Article
The Glass Flowers Collection, commissioned from Leopold and Rudolf Blaschka, was created in 1886 through 1936 to illustrate the plant kingdom for the Botanical Museum at Harvard University. The models are both examples of superb flameworking, and represent botanical sciences in the late nineteenth and early twentieth centuries. The Blaschkas' reference materials and the artistic license they sometimes incorporated are discussed. Emphasis is given to the early lifecycle series (1889, 1893) and the last models that depict blight on temperate fruits (1929, 1932, 1936).
 
Article
The use of the Blaschka marine models in North American educational institutions from 1870-1890 is detailed. Historical records of purchase from the Henry Augustus Ward papers and Leopold Blaschka's business notebooks and correspondence were examined to show how the models were received by curators and educators in North America, the significance of the models in marine biology education for secondary school teachers, and the role that Ward's Natural History Establishment played in the distribution of the models. A historical perspective of the business relationship between Henry Ward and Leopold Blaschka is presented. The taxa of the models ordered in North America are documented, as is the use of models demonstrating ontogeny of the organism. Educational practices of the period are explicated and the uses of the models to support contemporary biological concepts of the organism are elucidated through examination of Model 191a, a male colony of the hydroid, Tubularia.
 
Article
The Humboldt University of Berlin has a collection of Blaschka models which came from the teaching collection of the Zoological Institute and the former exhibition of the Museum of Natural History. Besides those from the Blaschkas other models from model makers like Adolf and Friedrich Ziegler in Freiburg, Rudolf Weisker and Paul Loth in Leipzig, Paul Osterloh, Marcus Sommer, and others were used for teaching purposes in the Zoological Institute. They were created in close cooperation between scientists, craftsmen, and artists and tell us about anatomical and zoological research of their time. The origin, history and application of different types of models are explained and compared.
 
Article
The presence of the diseases yaws and bejel are indicated by periosteal reaction patterns. The distributions of these two diseases in ancient North American human populations show evidence of climatic influence. Those ancient populations lacking either yaws or bejel (the null periosteal reaction pattern) can be found in the coldest parts of the Cold Winter Regions. Those populations with yaws (the poly-ostotic periosteal reaction) can be found in the milder portions of the Cold Winter Regions. The populations with bejel (the pauci-ostotic periosteal reaction) are found either outside of or marginal to Cold Winter Regions. The Bering Strait area is considered to be the gateway to the ancient New World. The cold climates present in this area should have influenced the routes available for the diseases to spread from population to population or by migration of infected populations into the Western Hemisphere. It is suggested that the coastal route with its milder maritime climate was the route taken by yaws when it entered the New World. The presence of bejel in ancient North America presents a conundrum. The climate would have blocked the spread of the disease from Siberia to Alaska in either Late Glacial or Holocene times. This suggests that our present view of migration routes is incomplete.
 
Article
Parrots (traditional order Psittaciformes) are one of the most instantly recognizable groups of modern birds. Their relatively large heads, squat necks and broad, curved bills help to make parrots so easily identifiable. However, the few early fossil parrots that have been discovered to date (Lower Eocene), do not necessarily possess this “parrot-like” cranial morphology. Even more surprisingly, early psittaciforms have mainly been found in the northern hemisphere (Walton-on-the-Naze, England; Messel, Germany, etc.), with only a few, relatively recent, essentially modern parrot remains being found within their present range (mainly in tropical and sub-tropical Australasia and South America). Fossil parrots remain rare and those that have been identified are often the subject of much debate. This paper is an attempt to accumulate and re-evaluate the current information available on parrot fossils—an intriguing group of birds with a complicated and elusive past.
 
Article
Insect trace fossils, such as burrows, pupation chambers and nests, can provide broad paleoecological insights by helping to define paleohydrology, effects of seasonality or conditions of associated paleosols. Insect traces adjacent to nesting sites of the dinosaur Troodon formosus in the Cretaceous (Campanian) Two Medicine Formation near Choteau, Montana, demonstrate such paleoecological utility. One outcrop in particular contains an abundance of insect burrows and pupation chambers in a calcareous paleosol. Most trace fossils are interpreted as apocritan (wasps and bees) burrows, brooding chambers and cocoons. Apocritans prefer to construct burrows and brooding chambers in well-drained soils during relatively dry conditions (avoiding wet seasons). Their trace fossils are consistent with previous inferences of semi-arid conditions and seasonality for the Two Medicine Formation. Moreover, apocritan nesting is likely to have occurred in the same places and conditions as dinosaur nests: well above the local water table and during dry seasons. Such trace fossils hold the potential for more precise definitions of paleoecological factors in dinosaur nest sites. For example, within the Two Medicine Formation, the Celliforma ichnofacies is commonly associated with eggs of T. formosus and Continuoolithus, but not with those of Maiasaura peeblesorum, perhaps indicative of subtle nesting site preferences.
 
Article
The type specimen of Toyotamaphimeia machikanensis (Diapsida, Crocodylia) from the Osaka Group (Plio-Pleistocene) of Osaka Prefecture, Central Japan, shows multiple abnormalities. The anterior third of the mandible was amputated and shows signs of healing. The right tibia and fibula were fractured, and each of them was later fused in dislocated position with callus formation. Additionally, there are two puncture marks on a dermal scute. Based on the morphologies of these pathologies, the fauna of the community in which this animal lived, and the behavior of extant crocodilians, it is suggested that this individual survived its injuries sustained during multiple intraspecific fights for territoriality or mating.
 
Article
Unguals of sauropod dinosaurs are notable for their unusual shape and orientation, and differ from those of graviportal mammals to which they are often compared. Early in their evolution, sauropod manual unguals underwent severe reduction, being lost on all digits except digit (D)-I. In contrast, the pedal unguals become hypertrophied and laterally compressed with an unusual angled orientation. Recent workers dismissed an early suggestion of a scratch-digging function, supporting instead substrate-gripping during locomotion, although neither hypothesis has been adequately tested, and rejection of the scratch-digging hypothesis was based on inadequate comparison. Here, we show that sauropod nesting traces are morphologically consistent with being excavated by scratch-digging, and that this behaviour is also observed in extant tortoises, which possess flattened unguals with a functionally analogous orientation. In this initial qualitative study, we surveyed claw morphology and use in a range of tortoises, based on previously published accounts and observation of specimens and video footage. Our findings suggest that there is a good case for re-examining the scratch-digging hypothesis for sauropods, although further work is required. The influence of reproductive behaviours on morphology is discussed, including the suggestion that the single manus claw of sauropods may have functioned for mate-gripping during copulation.
 
Fossil evidence for oviparity, parental care, multi-year maturation and juvenile sociality listed by genus where applicable.
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Article
Five factors, mobile terrestrial lifestyle, oviparity, parental care, multi-year maturation and juvenile sociality, contribute to a distinct life history for Mesozoic dinosaurs in comparison to extant archosaurs and mammals. Upright, para-sagittal gait reflects several synapomorphies of Dinosauria, and wide histological sampling suggests that multi-year maturation typified dinosaurs across a range of body sizes. Fossil support for juvenile sociality exceeds that for either oviparity or parental care. Implications of these factors include temporal segregation of adults for an extended, perhaps months-long reproductive cycle; spatial separation of adults and perhaps hatchlings to suitable nesting sites; increased likelihood for territoriality; reduced potential for long migrations; intraspecific niche segregation by age; population and community structure and macroevolutionary patterns. Fossil evidence for oviparity, parental care and juvenile sociality consists of combinations of adults, juveniles, embryos, eggs or traces and emphasises the importance of bonebeds and taphonomy in understanding dinosaur life-history strategies. Oviparity and parental care, predicted for dinosaurs by their extant phylogenetic bracket, have the least fossil support and cautions against overextending parsimonious interpretations to extinct taxa with the risk of obscuring novel or intermediate behaviours. Given the great diversity of Mesozoic dinosaurs, the proposed life history is hypothesised to represent only a general tendency.
 
Article
Traces of drilling predation by naticid gastropods were observed on 51 valves of the free-lying, semi-infaunal oyster Pycnodonte dissimilaris (Gryphaeidae) from the Paleocene Hornerstown Formation, in New Jersey. Stereotypic behavior of the predator is indicated by the highly constrained placement of drill holes, 94% of which are centrally located on the oyster shells. Predator-prey mismatches in size, involving small predators that drilled through the upper valves of relatively large oysters, are documented by comparison of outer borehole diameter, as an index of predator size, with the sizes of the oyster shells. Results of this analysis suggest that at least some prey were drilled epifaunally, as they were too large to be manipulated and buried by the predator. This indicates, together with reports of epifaunal drilling by living naticids, that such behavior is geographically and stratigraphically more widespread in the Naticidae than has previously been acknowledged. This in turn suggests that epifaunal drilling of prey is a plesiomorphic, opportunistic mode of behavior, conserved in the evolution of the Naticidae, that has permitted subsequent escalation or expansion in range of naticid foraging from a more narrowly defined infaunal paradigm into exposed intertidal refugia.
 
Article
Tayassu pecari is widely distributed across the Neotropical region, from northern Argentina to south-eastern Mexico. However, its fossil record is scarce; it is recorded since the middle Pleistocene to Holocene in Argentina, Brazil and Uruguay. This paper aims to: (1) update the systematic synonymy of this species; (2) review and update its geographic chronologic distribution and provide a new Lujanian record of Tayassu pecari in Buenos Aires Province and (3) discuss the paleoenvironmental and paleobiogeographical implications of this record. Considering the quantitative analysis performed, the fossil here recorded clearly integrates the group of Tayassu pecari. This specimen corresponds to the first record of Tayassu pecari in the central-northern region of the Buenos Aires Province. During Late Pleistocene, Tayassu pecari was distributed southern to its recent range, probably evidencing different paleoenvironment conditions. This species is the better adapted peccary to tropical and subtropical rainforests, but may also be present in arid environments. Consequently, Tayassu by itself is insufficient to infer the prevailing environmental conditions. However, according to the fauna associated with the specimen described here, it is possible to infer an open or semi-open and arid or semi-arid environment for the central-northern Buenos Aires region by Late Pleistocene times.
 
Article
Four species of the pleurotomariid genus Leptomaria E Eudes-Deslongchamps, 1864 are reviewed based on previously undescribed material from Bajocian deposits of the eastern Paris Basin. One of them, Leptomaria nicsimoni sp. nov., is introduced as a new species. A critical revaluation of the literature shows that Leptomaria has been broadly interpreted in the past, in contrast with the rather detailed description given by its author. This focused on shell characters, such as the width and position of the slit and selenizone, which have been overlooked by most subsequent authors. A revised diagnosis that reintroduces these characters is presented on the basis of the Bajocian material studied and of a survey of the relevant literature. This diagnosis, which is based also on other characters not considered before, excludes from Leptomaria several species previously assigned to it. The genus occurred from the Middle Aalenian to the Cenomanian mainly in the epicontinental seas of western Europe. It experienced a peak of diversity in the Bajocian, followed by a slow decline in Bathonian to Callovian times concomitantly with the appearance of the genus in the south-eastern margin of Tethys. Records in Upper Jurassic to Cretaceous sediments are sparse.http://www.zoobank.org/urn:lsid:zoobank.org:pub:FDAE7E20-F314-4FE2-902B-D9FFA195AC2E
 
Article
The ecosystem impact of megaherbivorous dinosaurs of the Morrison Formation would have depended on their abundance (number of animals per unit of habitat area) on the landscape. We constrain Morrison megaherbivore abundance by modelling dinosaur abundance in terms of carrying capacity (K), average body mass (ABM) and animal’s energy needs. Two kinds of model are presented: ‘demand-side’ models that estimate K in terms of the aggregate energy demand of the dinosaur community, and ‘supply-side’ models that estimate K in terms of retrodicted primary productivity. Baseline values of K, ABM and energy needs for the models are further derived from comparisons with modern large herbivores, and from the composition of the megaherbivore fauna from a particular stratigraphic interval of the Morrison, but in all models a broad range of fractions and multiples of these baseline parameters are considered. ‘Best-guess’ estimates of Morrison megaherbivore abundance suggest an upper limit of a few hundred animals across all taxa and size classes per square kilometre, and up to a few tens of individuals of large subadults and adults.
 
Article
Considerable controversy surrounds the extinction date for the dodo (Raphus cucullatus), and the last uncontrovertibly confirmed sighting is ascribed to Volkert Evertsz on an islet off Mauritius in 1662. Nevertheless, both Roberts and Solow (2003), using a statistical technique, and Hume et al. (20046. HumeJP, MartillDM, DewdneyC. 2004. Dutch diaries and the demise of the dodo. Nature. 429:6992.[CrossRef]View all references), drawing on Lamotius' hunting diaries (1685–1688), place the extinction date as late as 1690 and 1693, respectively. A well-known account of Benjamin Harry from 1681 seems to have been frequently dismissed as unreliable or anecdotal. Our purpose here is to provide new background information on Harry's scientific credentials that adds considerable credence to his 1681 report and thus adds to the likelihood of a late date for the dodo's demise, in agreement with the 1690 lower bound.
 
Article
The diversity of the family Bovidae (Mammalia) in the Plio‐Pleistocene of Africa is estimated by several indices and rank‐abundance curves. The broad observed pattern in East and South‐Africa is an increase in diversity during the second part of the Pliocene, followed by a decrease in the latest Pliocene or earliest Pleistocene. These changes are diachronic in the various areas, as are other faunal changes (in successive order, in Lake Turkana basin: West Turkana, Omo, Koobi Fora). High diversity is associated with a higher number of abundant species, whereas the subsequent, less diverse, assemblages have only 1 or 2 very abundant species. The decrease in diversity might be a consequence of the latest Pliocene global cooling, resulting in a decrease in primary productivity and other related parameters. There is, however, some evidence that more favourable conditions were restored afterwards.
 
Article
Although rare, dinosaurs are well preserved in calcareous nodules of the Santana Formation (Early Cretaceous, ?Albian) of the Araripe Basin, in northeastern Brazil. So far, including only a spinosauroid and three coelurosaurs, the dinosaur fauna appears depauperate. High theropod diversity in assemblages where other dinosaurs are rare or absent is not unique to the Santana Formation. It is seen also in several other assemblages, including Solnhofen and the Maevarano Formation of Madagascar. We consider several factors, including the occurrence of intraguild predation, the possibility that small theropods could subsist in marginal environments, and reliance on coastal resources, that may have been responsible for this apparent ecological imbalance. A new coelurosaur from the Santana Formation, here formally named Mirischia asymmetrica, is shown to be distinct from Santanaraptor placidus [Kellner, A.W.A. (199930. Kellner , AWA . 1999. Short note on a new dinosaur (Theropoda, Coelurosauria) from the Santana Formation (Romualdo Member, Albian) northeastern Brazil. Boletim do Museu Nacional, Nova Serie, Rio de Janeiro, Brasil, 49: 1–8. View all references) “Short note on a new dinosaur (Theropoda, Coelurosauria) from the Santana Formation (Romualdo Member, Albian) northeastern Brazil”, Boletim do Museu Nacional, Nova Serie, Rio de Janeiro, Brasil 49, 1–8]. Other theropods from the Santana Formation are briefly reviewed. Mirischia is a compsognathid, more similar to the European Compsognathus than to the Asian Sinosauropteryx.
 
Dorsal view of the holotype of B. maculata in Dominican amber. Scale bar 1⁄4 0.67 mm. 
Summary of Curculionoidea described from Dominican amber.
Dorso– lateral view of the holotype of B. maculata in Dominican amber. Arrows show two apical spurs at apex of fore tibia. Scale bar 1⁄4 0.67 mm. 
Ventral view of the holotype of B. maculata in Dominican amber. Scale bar 1⁄4 0.7 mm. 
Ventral view of head and thorax of the holotype of B. maculata in Dominican amber. Arrows show spurs at apex of fore tibia. A represents anal pedicel attaching a phoretic deutonymph of a uropodid mite to the mid femur of the fossil weevil. Scale bar 1⁄4 0.56 mm. 
Article
A new genus and species, Bicalcasura maculata n. gen., n. sp. (Coleoptera: Curculionoidea: Rhynchophorinae: Dryophthoridae) is described from Dominican amber as the first fossil member of the Tribe Diocalandrini. The new genus is characterised by procoxae located in the middle of the prothorax; a thick, short and strongly curved rostrum with the scape not reaching the pronotum; a weak extension of the rostrum in respect to the antennal attachment; slightly elongated fifth ventrite; narrow (not bilobed) third tarsomere and a pair of apical spurs on the protibiae. This set of characters separates the fossil from the extant genus Diocalandra Faust, 1894, the only other member of this tribe. A list of weevils (Curculionoidea) described from Dominican amber is included.http://www.zoobank.org/urn:lsid:zoobank.org:pub:D25F7915-3C49-4E22-A37C-F574F573C67D
 
Article
Forty-four specimens of the weevil subfamily Cryptorhynchinae (Coleoptera, Curculionidae) in amber from the Dominican Republic were examined and 30 species descriptions in four extant and six newly erected genera are presented. Included are descriptions of Anlemmus leptorhinus n. sp., n. gen., Apharosoma euryrhina n. sp., n. gen., Episcirrus isolepus n. sp., Lemmasomus anodontotus n. sp., n. gen., Neoulosomus (Neoulosomus) megus n. sp., Neoulosomus (Neoulosomus) scambus n. sp., Neoulosomus (Neoulosomus) leptosomus n. sp., Neoulosomus (Neoulosomus) megaholcus n. sp., Neoulosomus (Neoulosomus) microholcus n. sp., Neoulosomus (Neoulosomus) pedinus n. sp., Neoulosomus (Neoulosomus) pediosomus n. sp., Neoulosomus (Neoulosomus) platystegus n. sp., Neoulosomus (Neoulosomus) scambosomus n. sp., Neoulosomus (Neoulosomus) stenocalypus n. sp., Neoulosomus (Neoulosomus) stylolepus n. sp., Neoulosomus (Stenosomus) contorhinus n. sp., Neoulosomus (Stenosomus) tanyrhinus n. sp., Odontamera dolichosoma n. gen., n. sp., Paracamptopsis stenis n. sp., n. gen., Paraulosomus adenolepus n. sp., Pseudomoides clisaulis n. sp., n. gen., Semnorhynchus brachyrhinus n. sp., Semnorhynchus campostegus n. sp., Semnorhynchus contorhinus n. sp., Semnorhynchus euryaspus n. sp., Semnorhynchus eurystegus n. sp., Semnorhynchus leptostegus n. sp., Semnorhynchus megasomus n. sp., Semnorhynchus stenostegus n. sp. and Semnorhynchus tanyrhinus n. sp. Extant representatives of Episcirrus, Paraulosomus and Semnorhynchus have not been reported from Hispaniola.http://www.zoobank.org/urn:lsid:zoobank.org:pub:58543406-F511-499A-846C-DB2D8F4AA3EE
 
Article
A new genus and species of belid weevils, Pleurambus strongylus Poinar and Legalov, n. gen., n. sp. (Coleoptera: Belidae) in the tribe Allocorynini is described from Dominican amber. Belid fossils are quite rare and the new species is the first fossil member of the family from the Neotropics. This discovery suggests that belid diversity in Hispaniola during the Tertiary was higher than at present since no extant belids have been reported from the West Indies.http://www.zoobank.org/urn:lsid:zoobank.org:pub:DF79FF39-634D-4BD7-AD0B-F5FB3BBE1081
 
Dorsum of holotype of Dominimyza tanyacaena in Dominican amber. Scale bar 1⁄4 2.1 mm. 
Dorsum of head of Dominimyza tanyacaena in Dominican amber. FOB, fronto-orbital bristle (only one of the pair labelled); IV, inner vertical bristle (only one of the pair labelled); OB, ocellar bristles; OV, outer vertical bristle (only one of the pair labelled); PV, post-ocellar bristles. Scale bar 1⁄4 380 m m. 
Article
A new genus and species of snail-killing flies, Dominimyza tanyacaena n. gen., n. sp. (Diptera: Sciomyzidae), is described from Dominican amber. Diagnostic characters for Dominimyza include a propleuron with a strong bristle, an elongate porrect flagellum with a long, finely pubescent arista, divergent ocellar, post-ocellar and outer vertical bristles, convergent inner vertical bristles, two pairs of fronto-orbital bristles, scutellum with two pairs of marginal scutellar bristles, vallar bristles present, a strong bristle present near the middle of the anterior face of the mid-femora, a clear wing with fuscous areas, A1 fading as it nears the wing margin, R1 extending apicad of the anterior crossvein and the absence of pre-apical bristles on the fore tibia. This is the first description of a snail-killing fly in Dominican amber.http://www.zoobank.org/urn:lsid:zoobank.org:pub:6E080144-0C13-4511-8AAE-FAFEA3E1C1C2
 
Cretaceomira phalanx n. gen. et sp. holotype TMP 91.148.792 habitus diagrams. (a) Dorsal view corresponding to Figure 2(a). Medial depression of scutellum probably taphonomic artefact, setation omitted on left hemelytron for clarity, C vein of hind wing impressed on hemelytron (horizontal arrow), 'cells' in hemelytron membrane only visible as darkened areas (inclined arrows) and unclear whether this darkness is pigmentation or result of impression on abdomen. (b) Ventral view, corresponding to Figure 2(e). Abdomen truncated posteriorly, leaving only portions of apical sternal valves. Scale bar ¼ 0.5 mm. 
(Colour online) Cretaceomira phalanx n. gen. et sp. holotype TMP 91.148.792 photomicrographs. (a, b) Dorsal views, bright field and dark field images, respectively. (c,d) Photomicrographs of frons and profemur, respectively, corresponding to same regions in Figure 2(a). Black arrows in (c) mark trichobothria; white arrows mark trichobothrial bases (tubercles). Inclined arrows in (d) mark trichobothrial bases; horizontal arrow indicates anterolateral spine on pronotum. (e,f) Ventral views, bright field and dark field images, respectively. Bright lines within surrounding amber in (b) and (f) highlight fungal hyphae. Scale bars ¼ 0.5 mm. 
Article
A new genus and species of leptopodid bug, Cretaceomira phalanx McKellar and Engel, is described from Canadian Late Cretaceous (Campanian) amber originating near Grassy Lake, in southern Alberta, Canada. This new record is the first described for the family within the Mesozoic, extending their fossil range by at least 26 Ma. The discovery adds further support to the idea that the subfamily was once much more widespread than its modern, relict distribution in the tropics – adding an occurrence in warm temperate conditions, on the western side of Laurentia (in the modern Palearctic). Beyond confirming the presence of the lineage in the Cretaceous, their expanded distribution suggests that the group is likely to be found in other Cretaceous amber deposits. Furthermore, the distinctive disk-shaped amber nodule that contains the C. phalanx holotype provides limited support for the interpretation of Leptosaldinae as subcortical inhabitants of resin-producing trees as early as the Cretaceous.http://www.zoobank.org/urn:lsid:zoobank.org:pub:E324DF2B-8D99-42B3-BBAC-8F9DC3603490
 
Article
Eulechriops argyrosoma n. sp. (Curculionidae: Conoderinae: Lechropini) and Geratozygops platysoma n. sp., Geratozygops stenosoma n. sp. and Geratozygops arsinotus n. sp. (Curculionidae: Conoderinae: Zygopini) are described from Dominican amber. The small size, nearly parallel sides of the pronotum and silvery sheen distinguish Eulechriops argyrosoma from extant members of the genus, which have not been recorded from Hispaniola. Size and rostral and pronotal characters separate the three Geratozygops species from the single species (Geratozygops atropos) previously described from Dominican amber.http://www.zoobank.org/urn:lsid:zoobank.org:pub:89BC7F43-6C1A-4A6A-839B-CE94C7F6F140
 
Nab  ́n Basin, Ecuador. Upper, map showing location; lower, general photo of the fossil locality (facing South). Sediments of Saraguro Formation surround the Miocene basins Gir  ́n, Nab  ́n and Cuenca. 
(A) Carapace fragments of A. hondanus ; (B) schematic line drawings of buckler and movable osteoderms of A. hondanus , A. aequatorianus and D. novemcinctus . 
Article
A new species of dasypodid armadillo (Xenarthra, Cingulata), Anadasypus aequatorianus, from the late Miocene of Ecuador is described. The remains were collected in sediments of the Letrero Formation, Nabón Basin, which is part of several intermontane basins related to Andean uplift. The genus represents the oldest record of Dasypodini, which also encompasses Propraopus (Pleistocene–early Holocene) and Dasypus (?Miocene–Recent). The new species is based on several osteoderms, which show more derived features than Anadasypus hondanus, from the middle Miocene of Colombia. In order to test the affinities of A. aequatorianus within Dasypodini, we conducted a cladistic analysis of 24 morphological characters for 10 taxa. The most parsimonious tree supports the generic attribution of the new species and places Anadasypus basal to Propraopus and Dasypus, agreeing with the stratigraphic evidence. The faunas from tropical Andean areas differ noticeably from the better-known assemblages of the classic South American sequences. In the case of dasypodines, their geochronological distribution shows that they were historically restricted to tropical and subtropical environments and the main cladogenetic events of the group probably occurred at lower latitudes. In this context, the taxon described herein fills important temporal and geographic gaps of early Neogene armadillos from intertropical areas.http://www.zoobank.org/urn:lsid:zoobank.org:pub:9DC76603-D831-4E68-BE55-90113228E0F4
 
Article
Giant bear-dogs of the genera Amphicyon and Ischyrocyon (Carnivora, Amphicyonidae, Amphicyoninae) were the largest carnivorans in North America during middle and late Miocene (17.5–8.8 Mya) with a dental and skeletal morphology that combined features found in living Ursidae, Canidae, and Felidae. This study tests previously proposed models of diet and hunting behaviour of these extinct carnivorans. Relative grinding area (RGA) of lower molars and wear pattern on upper molars suggest that bear-dogs were carnivorous. Amphicyon and Ischyrocyon possessed skeletal features of both ambush (short distal limb segments) and pursuit (caudally bent olecranon process of ulna) living predators. Therefore, bear-dogs probably pursued their prey (mediportal ungulates) for a longer distance but at a slower speed than do living ambush predators. Upon catching up to its prey a bear-dog probably seized it with powerfully muscled forelimbs and killed it by tearing into its ribcage or neck with canines set in a narrow rostrum.
 
Postcranial Characters. Data Matrix
Metric Characters. Data matrix
Article
A systematic revision of the family Atoposauridae is presented, interpreting and reviewing their relationships. The seventy‐one characters have been divided into cranial, postcranial and metric which have been used in three separate cladistic analyses in order to discuss their concordance. Polarities, in each case, have been deduced from distinct outgroups. We have used a PHYLIP program (version 2.9). There are five valid taxa of Atoposauridae: Alligatorellus beaumonti (rejecting the two subspecific taxa) Alligatorium meyeri, Theriosuchus pusillus. Alligatorium depereti (which is transferred to a new genus Montsecosuchus) and Aloposaurus (discussed as a nomen dubium). The three cladograms are not fully concordant. The relative level of derivation in postcranial and cranial characters suggests congruence. The metric traits seem to retain, in general, a primitive condition. The final proposed cladogram clusters Alligatorium + Alligatorellus as the sister group of Montsecosuchus + Theriosuchus.
 
Article
Gastropod faunas from the Early Jurassic (Late Pliensbachian–Early Toarcian) marine deposits of Chubut Province, Argentina, are described from Lomas Occidentales, Cerro La Trampa and Puesto Currumil localities, representing eight species, three of them new. These are Scurriopsis? sp., Chartronella gradata sp. nov., Calliotropis? sp., Pleurotomaria sp., Leptomaria sp., Hamusina? wahnishae sp. nov., Colpomphalus musacchioi sp. nov. and Jurassiphorus? cf. triadicus Haas. The gastropod assemblage reported here testifies paleobiogeographical connections with other coeval gastropod associations from the western Tethys. However, Chartronella, Hamusina and Jurassiphorus may represent survivors of Triassic associations, considering the ancient seaway from Peru as the most plausible hypothesis for biotic exchange of these faunas during the Late Triassic–Early Jurassic boundary. An abundant and diverse invertebrate fauna such as corals, echinoderms, cephalopods, brachiopods, bivalves and other gastropods found in association with the gastropods described here characterises a shallow marine environment for the gastropod-bearing rocks.http://www.zoobank.org/urn:lsid:zoobank.org:pub:7B8EAFC0-3AC0-4F91-97A5-22AAC6A19909
 
Molecular phylogenies of Panthera and its closest relatives modified from (A) Johnson and O’Brien (1997), (B) Collier and O’Brien (1985), (C) Johnson et al. (2006), (D) Yu and Zhang (2005), (E) Davis et al. (2010) and (F) Barnett et al. (2009). 
Averages for each linear measurement used within statistical analyses.
Strict consensus trees found when (A) all outgroups were assigned, (B) Crocuta crocuta was the assigned outgroup, (C) Pseudaelurus validus was the assigned outgroup, (D) Metailurus spp. was the assigned outgroup and (E) Proailurus lemanensis was the assigned outgroup. Bootstrap values are indicated by % and are in bold and nodes of importance are indicated by (a) Panthera leo , Panthera tigris and Panthera atrox clade and (b) Panthera. 
Article
The phylogenetic position of Panthera atrox within Felidae is still controversial despite many morphological and molecular studies addressing its relationships. This is in part due to the lack of consensus on a tree for Panthera. These inconsistencies suggest the need for further analysis and perhaps even different methodology to better understand pantherine evolution. Morphologic characters from the skull and dentary were analysed within Panthera to elucidate pantherine phylogeny. Extant taxa included Panthera leo (African lion), Panthera tigris (tiger), Panthera onca (jaguar), Panthera pardus (leopard), Uncia uncia (snow leopard) and Neofelis nebulosa (clouded leopard). Four outgroups were used: Crocuta crocuta (spotted hyena), Metailurus spp., Proailurus lemanensis and Pseudaelurus validus. Our study found a clade containing Panthera leo, Panthera tigris and Panthera atrox, suggesting that Panthera atrox is more closely related to the African lion and the tiger than the jaguar, in contrast to what has been recently proposed. Moreover, gross morphological similarities between Panthera atrox and Panthera onca are more likely the result of convergent hunting styles and/or prey selection, rather than phylogenetic affinity.
 
Article
The occurrence of approximately 100 rugose coral genera has been confirmed in the Devonian carbonate dominated successions of Australasia. Their temporal distribution shows that the largest faunal turnovers were in the Pragian and Givetian, with profound extinction events at or near the ends of the Emsian, Givetian and Frasnian. The evolutionary innovation and diversification of the Early Devonian rugose corals of eastern Australia are characterized by a high turnover rate in the late Lochkovian—Pragian and strong dynamism of radiation from late Pragian to medial Emsian, implying considerable dispersal to South China, central Asia and Europe.
 
Article
The phylogenetic relationships of species attributed to the ornithopod family Hypsilophodontidae are evaluated using morphological characters from the skull, dentition, and postcranium. Based on our analyses, Hypsilophodontidae constitutes a monophyletic taxon that comprises the sister taxon to Iguanodontia, together forming Euornithopoda. Three clades within the family are consistently demonstrated: Zephyrosaurus schaff+Orodromeus makelai, Parksosaurus warreni+Hypsilophodon foxii and Yandusaurus hongheensis+Othnielia rex. Thescelosaurus neglectus is the sister taxon to these six genera and constitutes the basal hypsilophodontid. Tenontosaurus tilletti is the basal member of Iguanodontia, with species of Dryosaurus and Camptosaurus as higher taxa within the clade. To understand the effects missing data may have on tree topology, tree length, and consistency indices, poorly represented characters were secondarily removed from the character matrix. In these analyses, all relationships remain stable, but tree length and consistency index decrease with increasingly more complete culled data sets. An average of 42.5 million years is accumulated as minimal divergence time for the hypsilophodontid and basal iguanodontian relationships described here. These figures underscore the large amount of hypsilophodontid evolution yet unaccounted for in the fossil record.
 
Article
The Jahrum Formation act as reservoir rocks in the Zagros Mountains west of Iran. For the study of this formation, a stratigraphic section of Lapoee which is situated north of Shiraz has been examined. Petrographic and stratigraphic results along with field observations show that the Jahrum Formation consists of cream-grey thin-to-medium-bedded limestone so that at the top of the formation, they are locally changed to dolomite. The Jahrum Formation overlies the Sachun Formation. We also found Nubecularids as paleoecology indicators in middle parts of the Jahrum Formation. The presence of Nubecularids in the Lapoee stratigraphic section (i.e. the Jahrum Formation) indicates a lagoon depositional environment.
 
Article
We report on a new species of basal ornithuromorph bird, Piscivoravis lii gen. et sp. nov., based on a well-preserved and nearly complete specimen from the Lower Cretaceous Jiufotang Formation in western Liaoning Province, northeastern China. The new specimen preserves several unique anatomical features previously unreported in Early Cretaceous ornithuromorphs, such as a robust furcula with strongly tapered omal tips, a broad sternum without craniocaudal elongation and large and strongly curved manual unguals. Phylogenetic analysis indicates that Piscivoravis is more derived than Archaeorynchus, but in a basal polytomy with Jianchangornis, Patagopteryx, and the clade including all more derived ornithuromorphs. The preserved wing and tail feathers provide new information on feather diversity and evolution in Early Cretaceous ornithuromorphs. The preservation of fish bones ventral to the dentary and in the stomach provides direct evidence that the new species was piscivorous – previously only reported in Yanornis, and as in some living birds, was capable of moving food bidirectionally through the alimentary canal.http://www.zoobank.org/urn:lsid:zoobank.org:pub:92F23126-9E89-4E51-9700-C6608E0D66EB
 
Article
Five new genera, Turononemonyx n. gen. (type species: Turononemonyx samsonovi n. sp.) (Nemonychidae: ? Cretonemonychinae: ? Cretonemonychini), Falsotanaos n. gen. (type species: Falsotanaos convexus n. sp.), Pretanaos n. gen. (type species: Pretanaos ocularis n. sp.), Longotanaos n. gen. (type species: Longotanaos rasnitsyni n. sp.) from Brentidae: Apioninae: Tanaini) and Turonerirhinus n. gen. (type species: Turonerirhinus karatavensis n. sp.) from Curculionidae (Erirhininae: Erirhinini), and seven new species, Falsotanaos convexus n. sp., Paratanaos samsonovi n. sp., Pretanaos ocularis n. sp., Longotanaos rasnitsyni n. sp., Turonerirhinus karatavensis n. sp., Turonerirhinus punctatus n. sp. and Turonerirhinus poinari n. sp., are described from Kzyl-Dzhar locality (Kazakhstan, Upper Cretaceous, Turonian).http://www.zoobank.org/urn:lsid:zoobank.org:pub:13E0316E-C229-471A-90AA-2D71253B12F9
 
Fossils from Ahl al Oughlam. (a) C. dbaa , holotype right lower jaw, AaO-12; (b) Hyaenictitherium barbarum , holotype right lower jaw, AaO-1340; (c) Panthera cf. pardus , right lower jaw, AaO-13; (d) A. aicha , holotype skull, AaO-1456; (e) Homotherium sp., fragment of muzzle with canine (bone removed), AaO-4566; (f) H. abdelalii , holotype right lower jaw, AaO-1341; (g) L. fatimazohrae , left lower jaw, AaO-3498; (h) Mellivora cf. capensis , left lower jaw, AaO-3497; (i) Ursus cf. etruscus , right m1, AaO-332; (j) O. emmonsi , femur AaO-4731, plantar view; (k) Anancus osiris , left dp3– dp4, AaO-3935; (l) T. atlanticus , left lower jaw with m2– m3, AaO-228; (m) H. pomeli , right upper tooth row, AaO-2048 and (n) K. phacochoeroides , skull, AaO-3655. Scale: 5 cm for (f– i); 7.5 cm for (c), (k) and (m); 10 cm for (a), (b), (e) and (l); 15 cm for (d) and (j) and 30 cm for (n). 
(a) C. mauritanicum , skull from ‘Grotte des Rhinoc  ́ros’; (b) Kolpochoerus cf. marocanus , m3 from Thomas L; (c) Lynx thomasi , holotype lower jaw from fissures in Oulad Hamida 1 Quarry; (d) Gazella ( Deprezia ) psolea , holotype skull from Ahl al Oughlam, AaO-3682; (e) Beatragus whitei , skull from Ahl al Oughlam, AaO-276. Scale: 5 cm for (b) and (c); 15 cm for (d) and 30 cm for (a) and (e). 
Chronological range of some of the most significant taxa in sites around Casablanca (in bold) and in some other important northwestern African sites. Thomas I-ABCE yielded only rodents. 
Article
In the frame of the Franco–Moroccan ‘Programme Casablanca', several important new Late Miocene to Late Pleistocene mammalian localities have been excavated in the Casablanca area. The rodent fauna of Lissasfa attests to faunal exchanges with Spain and shows that the ‘Quaternary' of Casablanca dates back to the Late Miocene. Ahl al Oughlam, with more than 100 vertebrate species, is by far the richest paleontological locality of northwestern Africa, but shows that by Late Pliocene, at 2.5 Ma, faunas of this region were already less diverse than in eastern Africa. The Thomas and Oulad Hamida quarries yield, in several continental levels interstratified with high-marine transgressive ones, a succession of late Early to Late Pleistocene faunas associated with lithic industries and Homo remains, which greatly help calibrating mammalian evolution in this part of Africa. The Late Pleistocene is also documented by several new sites, all of which, unfortunately, were destroyed before they could be properly excavated. All sites are threatened by urbanisation, emphasising the need for preservation of the few remaining ones.
 
Article
Due to their abundance, taxonomic and morphological diversity, wide range of body sizes and broad geographical distribution, titanosaurian sauropods were one of the most important Cretaceous herbivorous dinosaur groups. Consequently, titanosaurs constitute one of the best samples in which to evaluate the relationship between bony structures and unpreserved soft-tissues within Sauropoda. We reconstruct the morphology and interpret the implications of selected soft-tissues associated with the titanosaurian caudal skeleton. These tissues, especially the M. caudofemoralis longus (CFL), exerted a considerable influence on the anatomy of the caudal vertebrae and haemal arches. In all studied titanosaurian taxa, the reconstructed caudofemoral musculature corresponds to one of three principal morphotypes that accord with previously recognised phylogenetic patterns within the clade. Basal titanosaurians had an elongate M. CFL that extended for much of the proximal half of the tail; in saltasaurines, this muscle was much shorter. Non-saltasaurine lithostrotians exhibited an intermediate condition. Furthermore, the differing position of the fourth trochanter, and therefore, the insertion of the caudofemoral muscles, among various titanosaurian taxa suggests distinctions in the locomotor function of these animals.
 
Geosaurus sp. NHMUK PV R36638, isolated tooth. (A) Labial view, (B) oblique labial/carinal view, (C) apical view, (D) basal view, (E) lingual view, (F) carinal view, we cannot determine whether it is the mesial or distal margin. Note that in (A) the light is reflecting off the left lateral facet, clearly distinguishing it from the central facet. Scale bar ¼ 5 mm.
Article
We report the oldest known specimen of the metriorhynchid crocodylomorph genus Geosaurus, and the first specimen discovered from the Lower Kimmeridge Clay Formation of England (Kimmeridgian stage, Rasenia cymodoce Sub-Boreal ammonite Zone). This specimen, an isolated tooth, has the tri-facetted labial surface morphology that is unique to Late Jurassic species of Geosaurus. Its dimensions suggest that it is one of the posterior teeth. Macrowear on the labial surface (enamel spalling) shows evidence of tooth–food abrasion. The presence of Geosaurus near the base of the lower Kimmeridgian, along with the recently re-described middle Oxfordian specimen attributable to Torvoneustes, shows that the subclade Geosaurini evolved and diversified prior to the Kimmeridgian. Members Geosaurini evolved a diverse array of sophisticated feeding mechanisms, including durophagous forms (Torvoneustes), barracuda-like forms with ‘scissor-like’ occlusion (Geosaurus), species reminiscent of false killer whales/Type 1 North Atlantic killer whales (Dakosaurus) and a large genus similar to extant Type 2 North Atlantic killer whales (Plesiosuchus). With the description of the isolated Geosaurus tooth, all four Geosaurini genera are now known from the Lower Kimmeridgian Clay Formation. The craniodental plasticity of Geosaurini, and the astonishing range of feeding mechanisms they evolved, is unparalleled amongst thalattosuchians.http://www.zoobank.org/urn:lsid:zoobank.org:act:36B1FB4C-C20E-41C2-BC19-BAAB4E9D1612.
 
Article
We report the only definite specimen of the teleosaurid crocodylomorph genus Machimosaurus from the Kimmeridge Clay Formation of England. This specimen (an isolated tooth) is now the only evidence of Machimosaurus in the Kimmeridge Clay Formation because a large skull and mandible, previously considered to be of Machimosaurus mosae, was recently shown to pertain to a metriorhynchid crocodylomorph. The tooth described herein was originally figured in 1884 as a tooth crown from a metriorhynchid crocodylomorph. However, its conical shape, blunt apex and distinctive enamel ornamentation are characteristic of the teleosaurid genus Machimosaurus. That Machimosaurus, and teleosaurids in general, were so rare in the Kimmeridge Clay Formation suggests that these marine crocodylomorphs did not commonly use this seaway. Their rarity is in contrast to contemporaneous deposits from continental Europe where teleosaurid remains, including Machimosaurus, are far more common. These continental deposits were deposited in shallow-marine/brackish ecosystems, suggesting that teleosaurids were largely restricted to coastal marine environments.
 
DFs of the abundant specimens of N. gualteriana in the Indian subcontinent are shown. Names of some states are given within parentheses. 
DF data of N. gualteriana collected from many geographic locations of India and nearby areas are listed here. 
An array of drilled specimens of N. gualteriana. Drillholes are mostly restricted on the apertural side of the outer whorl. A few drillholes are located abaperturally (see arrows) and one of them is an incomplete drill hole. 
Vertical and radial distributions of naticid drillholes are shown for Chandipur samples. (A, B) Vertical distribution with respect to the distance from the apex: (A) apertural view, (B) abapertural view. (C) Radial distribution of drill holes among four quadrants. 
Relationship between OBD (proxy for predator size) of naticid drillholes and prey shell height of N. gualteriana. Square: Chandipur 2011; circle: Chandipur 2012 (trend line with steeper slope). 
Article
Although common, confamilial naticid predation intensity was not very high in the geological record. Here, we gathered modern confamilial predation data from the Indian coasts and showed that confamilial naticid predation on a naticid species, Natica gualteriana, is exceptionally high at Chandipur, one of our studied areas. We studied the different aspects of confamilial predation from the Indian coasts and showed that the predators in Chandipur were highly efficient as evident from high drilling frequency (DF), site stereotypy and low prey effectiveness. Unusually high DF on N. gualteriana may be attributed to its new arrival in Chandipur where it faced competitive elimination through predation by sympatric naticid predators. Reports of failed invasion are rare. Natica gualteriana is a small invader and therefore its invasion success is threatened by resident populations of large species that extensively drill on young individuals of N. gualteriana just to break the bottleneck of their own offspring from competition.
 
Article
Heterodont dentition sometimes including multicuspid crowns appeared in numerous fossil forms through all main lineages of the Crocodyliformes. Teeth in these complex dentitions frequently bear wear facets that are exclusive indicators of tooth–tooth occlusion. Besides, dental features, specialisations of the jaw apparatus, jaw adductors and mandibular movement can be recognised, all reflecting a high variability of jaw mechanism and of intraoral food processing. Comparative study of these features revealed four main types of jaw mechanism, some of which evolved independently in several lineages of Crocodyliformes. Isognathous orthal jaw closure (precise jaw joint, rough wear facets) is characteristic for heterodont protosuchians and all forms possessing crushing posterior teeth. Proal movement (protractive powerstroke) occurred independently in Malawisuchus and Chimaerasuchus is supported by the antagonistic, vertically oriented carinae. Developed external adductors are the main indicators of palinal movement (retractive powerstroke) that evolved at least two times in various South American taxa. The fourth type (in Iharkutosuchus) is characterised by lateromedial mandibular rotation supported by extensive horizontal wear facets. This evolutionary scenario resembles that of the masticatory system of mammals and suggests that the ecological roles of some mammalian groups in North America and Asia were occupied in Western Gondwana by highly specialised crocodyliforms.http://www.zoobank.org/urn:lsid:zoobank.org:pub:D6CE962F-2B38-47F8-BD4B-B9E035917F20
 
Article
Triassic tracks and trackways assigned to dinosaur trackmakers or closest relatives have been mentioned from several Middle to the latest Triassic successions from both northern and southern Pangea. At present, the earliest gondwanan records are those from the Middle Triassic Los Rastros Formation in west-central Argentina. A reanalysis of Los Rastros ichnites at the Ischichuca area, including new material, has revealed the presence of a more diverse ichnofauna than previously suspected. The ichnocoenosis includes several tracks and trackways of bipeds with functionally tridactyl digitigrade pes, well developed claws, and a parasagittal posture of the hindlimbs. Previously, some large tridactyl footprints from the Ischichuca area were allied to theropod dinosaurs, although no synapomophies are preserved in the three-toed footprints that might discriminate among theropods, basal saurischians and basal ornithischian groups as their possible trackmakers. If the Ischichuca trackmakers are referred to a dinosaur taxon and/or to a close dinosaur sister-taxon, their presence in the Los Rastros levels suggests that derived dinosauriforms (including dinosaurs) had diverged and acquired their characteristic functionally tridactyl pes by at least the Middle Triassic, something that the body-fossil record has failed to document to date.
 
Article
Ecological studies of extant tetrapod predators indicate that morphologically similar species which coexist in the same habitats routinely reduce interspecific competition for food by regular spacing of body size. The biggest predator species in the assemblage often differ more from one another in size than the smallest species. When coexisting carnivore species do not differ greatly in size, they commonly show morphological differences related to prey handling that may reduce dietary overlap. If carnivore species are very similar in both size and morphology, competition is avoided by habitat partitioning. Two tyrannosaurid species from the late Campanian Dinosaur Park Formation of western Canada are similar in both size and morphology, suggesting that they were segregated on the basis of habitat and/or biogeographic province. However, consideration of the living-space requirements of predator species of such large body size suggests that this kind of spatial separation would only have been possible had tyrannosaurids been more like ectotherms than endotherms in their metabolic rates. Distribution of different large theropod species across different, and surprisingly small (for the size of the animals) portions of Mesozoic landscapes may also account for the remarkably high diversity of morphologically similar large theropods in other dinosaur faunas.
 
Map showing the fossil locality.  
(Colour online) (A) Fossil leaf of U. palaeozeylanica Shukla and Mehrotra, sp. nov. showing shape size and venation pattern; (B) modern leaf of U. zeylanica showing similar shape, size and venation pattern as in the fossil; (C) enlarged portion of the fossil leaf showing primary vein (white arrow), brochiododromous venation (red arrows), exmedial tertiary vein forming loop (blue arrows); (D) the modern leaf showing similar venation pattern (red arrows), exmedial tertiary vein forming loop (blue arrows) and primary vein (white arrow) (scale ¼ 1 cm).  
(Colour online) (A) – (C) Paratypes of the fossil leaf of U. palaeozeylanica Shukla and Mehrotra, sp. nov.; (D) enlarged view of the fossil leaf showing primary vein (black arrow), intersecondary veins (white arrows), random reticulate tertiary veins (blue arrows) and angle of origin of secondary veins (red arrow); (E) enlarged view of modern leaf of U. zeylanica showing similar kind of intersecondary veins (white arrows), random reticulate tertiary veins (blue arrows) and angle of origin of secondary veins (red arrow) (scale ¼ 1 cm).  
(Colour online) Map showing the present (dotted line) and fossil distribution of Uvaria (red stars) (after Zhou et al. 2012).  
Article
During the early Eocene, Rajasthan was positioned near the equator and had a warm and humid tropical climate dominated by tropical rainforests like the present-day equatorial forests of South India. Many of the plants retrieved as fossils from Rajasthan are growing there as refugee. This study further strengthens this view as it reports a new species of Uvaria L. from the early Eocene sediments of Bikaner (Rajasthan) showing its best resemblance with the extant U. zeylanica Deless. ex DC., which is presently growing in the evergreen forests of South India and Sri Lanka. The genus is thought to have originated in Africa, and the present finding gives an idea about its geologic distribution in Asia and Australasia via India relying on ‘stepping stone’ hypothesis during the Early Eocene Climatic Optimum (EECO) when climatic conditions were favourable for the luxuriant growth of tropical vegetation. A general cooling trend after EECO and change in the configuration of land and sea affected the climate on the regional scale causing total devastation of tropical evergreen forests that existed in western India during the depositional time; this change is ultimately responsible for creating dry and desertic conditions prevailing in the area at present.
 
Article
Marine reptiles are an adaptive assemblage including a mosaic of forms with fully marine groups (ichthyosaurs, “nothosaurs”;, plesiosaurs, placodonts, thalattosaurs and hupehsuchians), as well as groups containing continental representatives (turtles, crocodiles, lizards and snakes). Forty‐six families of marine reptiles are recorded during the Mesozoic. The fossil record of marine reptiles is punctuated by two major extinctions at the Middle‐Late Triassic transition (loss of 64% of families) and at the Cretaceous‐Tertiary boundary (36% of families died out). The Ladinian‐Carnian boundary event coincides with an important regressive phase and affects essentially coastal forms. The K/T boundary is characterized by selective extinctions among marine reptiles, probably linked with a break in the food chain.
 
Article
Silica phytoliths in grasses are thought to serve as a defence mechanism against grazing ungulates by causing excessive tooth wear. It is posited that they contributed to the evolution of hypsodonty in these animals. However, some have questioned whether grass phytoliths can abrade enamel. Here Mohs hardness testing was conducted on Blue Grama grass (Bouteloua gracilis) to determine phytolith hardness. Microindentation was performed on horse and American bison molars to establish dental constituent hardness values. To infer the phytoliths' abrasion capacity, the hardness values were contrasted. Phytolith hardness ranged from 18.0 to 191.5 HV. This is considerably softer than the values obtained for ungulate enamel, which range from 332.6 to 363.4 HV, but harder than the other dental constituents. Although Blue Grama phytoliths are incapable of directly abrading enamel, when viewed in conjunction with other data on phytolith hardness, there is considerable variation across grass species and some phytoliths are actually harder than ungulate enamel. Blue Grama grass phytoliths may even promote enamel wear due to pressure accentuation caused by the recession of softer tissues. Given these findings and considerations, it is plausible phytoliths served an integral role in the co-evolution of grasses and herbivorous ungulates, although more testing is needed to bear this out.
 
Article
Polyphyletic or monophyletic origins of mammals have been subjects of considerable controversy for a century. Late Triassic-Early Jurassic mammals are more diverse than previously thought. The stumbling block in establishing mono- or polyphyletic origins of mammals is the uncertain position of the Haramiyidae (the oldest Multituberculata, and possibly the oldest mammals), known only from isolated teeth. Triconodonta and Theria probably shared an unknown common ancestor, while Monotremata possibly branched from early Eupantotheria at the end of the Early Jurassic, before the Dryolestoidea did, from the forms in which the cochlea started to coil and small cerebellar hemispheres developed. Aegialodontia gave rise to Metatheria but not to Eutheria. Deltatheroida belongs to Metatheria. A group of Cretaceous therian mammals with tribosphenic molars informally classified as “Tribotheres” cannot be assigned either to Metatheria or Eutheria.
 
Article
On the basis of a well‐preserved pelvis of Anhanguera sp. from the Lower Cretaceous (Aptian) of the Chapada do Araripe, Brazil, the problem of terrestrial locomotion in pterosaurs is discussed. A three‐dimensional reconstruction of the pelvis led to a lateral, dorsal and posterior orientation of the acetabula. By use of the preserved proximal ends of the femora of the same individual, the articulation in the hip socket could be tested. The normal articulation of the femur resulted in a horizontal position of the femur shaft, probably during flight. For constructional reasons the femur could not be brought down to a vertical position. Therefore, a parasagittal swing of the femora necessary for a bird‐like stance and gait must have been impossible. It is suggested that in pterosaurs the wing membrane was attached to the upper leg, which helped in stretching, steering and cambering.Moreover, on the basis of comparisons of the fossil preservation of pterosaurs Compsognathus and Archaeopteryx in the Solnhofen limestone, it is concluded that the femora of pterosaurs were splayed out laterally, and that they had a semi‐erect gait. They were not bipedal animals, but had to use their fore limbs as well on the ground. Nevertheless, as vertebrates extremely adapted to flight, they could not have been able quadrupeds, either.
 
Article
A summary of recent studies on the interrelationships of pterodactyloid pterosaurs is used as a framework for reassessing the taxonomic status of Zhejiangopterus, a new, long‐necked, Late Cretaceous pterosaur from China that has been assigned to the Nyctosauridae. Characters cited in support of this decision include: a notarium, edentulous jaws, and lack of a cranial crest. However, none of these is diagnostic of the Nyctosauridae. Zhejiangopterus exhibits a number of derived characters (orbit relatively small and located in a low position, posteroventrally facing occiput, features of the humerus and ‘T‐shaped’ cross‐section of wing phalanges two and three) only otherwise found in azhdarchids, thus we propose that Zhejiangopterus be reassigned to the Azhdarchidae.
 
Article
Mass extinctions of varying magnitude prune the continuous diversification predicted by Darwinian evolutionary processes. They are caused by events that are too rare to become adaptatively accommodated. Their effects depend not only on the nature and magnitude of the triggering event but also on the state of the biosphere at the particular time. This is most clearly shown by the existence of Golden Ages preceding all Phanerozoic mass extinctions. These coincide with greenhouse periods, in which doomed clades gave rise to heteromorphs, deviating in strange ways from established bauplans. When critically examined, the seemingly ‘decadent’ morphologies of Schindewolf's ‘typolytic stages’ turn out to have been highly functional. The paradoxical link between adaptive peaks and evolutionary failure can now be explained. Specialisation tends to increase vulnerability (1) by narrowing niches and (2) by the retention of clade-specific conservative features that happen to become fatal Achilles’ Heels for entire clades in the face of a particular perturbation. Following extinctions, the availability of open niches favoured relatively rapid diversification of more innovative clades and their rise to ecological dominance (Schindewolf's ‘typogenetic stage’). Although the long-term changes can be observed only in the fossil record, Golden Biotopes in the present biosphere show that the Darwinian process may also be promoted by ecological isolation. As a result, clade histories do resemble individual biographies, but for ecological rather than orthogenetic reasons. This insight may help us to deal with the present mass extinction caused by our own species.
 
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George Poinar
  • Oregon State University
Sterling Nesbitt
  • Virginia Polytechnic Institute and State University
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  • Institute of Systematics and Ecology of Animals
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Stephen B Heard
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