Louis L. Jacobs

• PhD
• Southern Methodist University

A large data set of new and previously published measurements of δ¹³C values derived from tooth enamel (n = 223, of which 93 are new) are compiled to explore patterns of foraging area preferences of Late Cretaceous mosasaurid squamates over evolutionary time scales (~93–66 Ma). Our results indicate that small-bodied halisaurines are restricted to a...

The jigsaw-puzzle fit of South America and Africa is an icon of plate tectonics and continental drift. Fieldwork in Angola since 2002 allows the correlation of onshore outcrops and offshore geophysical and well-core data in the context of rift, sag, salt, and post-salt drift phases of the opening of the central South Atlantic. These outcrops, rangi...

Here we trace the saga of the rocks and fossils discovered along Stevenson Road, northern Malawi. Fish and bivalves discovered along the road were proclaimed the first fossils of Central Africa. In the late 19 th and early 20 th centuries they became a large part of the ‘Tanganyika Problem,’ the notion of whether a Jurassic incursion of the sea lef...

We present the first description of Jurassic vertebrate fossils from Texas. The vertebrate specimens were collected from the Upper Jurassic Malone Formation in the Malone Mountains of western Texas. The specimens are fragmentary and not particularly diagnostic, but probably represent elements of plesiosaurians. One specimen is similar to the caudal...

The puzzle-like fit of Africa and South America reflects the tectonically driven opening of the South Atlantic Ocean beginning over 130 mya. By 90 Ma, the North and South Atlantics were conjoined. The introduction of Cretaceous marine reptiles into the central South Atlantic from the north coincides with through-flow in the Equatorial Atlantic Gate...

Here, we describe the first pterosaur remains from Angola, an assemblage of fourteen bones from the Lower Maastrichtian marine deposits of Bentiaba, Namibe Province. One new species is introduced, Epapatelo otyikokolo, gen. et sp. nov., which comprises an articulated partial left humerus and ulna as well as an articulated left ulna and radius (from...

Cistecephalidae are a relatively basal clade of dicynodonts, well-nested within emydopoids, and known to have multiple adaptations to a fossorial lifestyle. In recent years cistecephalid taxonomic diversity has been progressively increasing and important insights into the osteology, soft-tissue anatomy, and paleobiology of the clade have improved c...

Snakes comprise nearly 4,000 extant species found on all major continents except Antarctica. Morphologically and ecologically diverse, they include burrowing, arboreal, and marine forms, feeding on prey ranging from insects to large mammals. Snakes are strikingly different from their closest lizard relatives, and their origins and early diversifica...

Compared to abundant dinosaur faunas, fish materials are scarce in the Nemegt Formation (Maastrichtian) of Mongolia except for isolated centra assigned to the Hiodontidae (Osteoglossomopha). Here we report new additional fish materials collected from the Nemegt Formation. They include skull parts (quadrate, premaxilla, and dentary), isolated and ar...

A new ankylosaurid dinosaur, Tarchia tumanovae sp. nov., has been recovered from the Upper Cretaceous Nemegt Formation of Mongolia. It includes a well-preserved skull, dorsal, sacral, caudal vertebrae, sixteen dorsal ribs, ilia, a partial ischium, free osteoderms, and a tail club. The squamosal horns of T. tumanovae are divided into two layers, the...

We report a new specimen of the plesiosaur Cardiocorax mukulu that includes the most complete plesiosaur skull from sub-Saharan Africa. The well-preserved three-dimensional nature of the skull offers rare insight into the cranial anatomy of elasmosaurid plesiosaurians. The new specimen of Cardiocorax mukulu was recovered from Bentiaba, Namibe Provi...

Cistecephalidae is a relatively basal clade of dicynodonts, well-nested within emydopoids, and known to have multiple adaptations to a fossorial lifestyle. In recent years cistecephalid taxonomic diversity has been progressively increasing and important insights into the osteology, soft-tissue anatomy, and paleobiology of the clade have improved co...

Fossil records generally inform paleobiologists about extinct taxa and rates of evolution measured at the scale of millions of years. Good records that are densely sampled through time can reveal species level details such as longevity in local sections. Yet fossil data normally do not address details of lineage microevolution because the density t...

Fossil records generally inform paleobiologists about extinct taxa and rates of evolution measured at the scale of millions of years. Good records that are densely sampled through time can reveal species level details such as longevity in local sections. Yet fossil data normally do not address details of lineage microevolution because the density t...

The unique geological, geophysical, and tectonic setting of the Indian Subcontinent created a theater of evolution that provided a relatively insulated refuge for origination and early diversification of many Mesozoic and early Cenozoic age vertebrate groups. This phenomenon continued into the Miocene Epoch in association with developing physical b...

The Miocene small mammal fossil record of South Asia includes previously undocumented shrews as a minor element. Nonetheless, fossil Soricidae, especially in the Siwalik deposits of the Potwar Plateau, Pakistan, offer early records of the Subfamily Crocidurinae, particularly a new species of the crocidurine Suncus. In addition to elucidating shrew...

The volcanic rocks of the Catoca Diamond Mine, located in northeastern Angola, were formed in a volcanic eruption ~118 million years ago (Ma). Early Cretaceous mammalian, crocodilian, and sauropod dinosaur footprints were discovered in crater lake sediments above ~118 Ma tuffisitic kimberlites (Pervov et al., 2011). These footprints are among the r...

For two hundred years the status of rodent suborders has been unstable. What are the natural groupings of extant rodent families? The formal recognition of rodent suborders has remained challenging and consensus has been elusive. Classically conceived rodent suborders are widely viewed as artificial, but no universally accepted classification has e...

[This corrects the article DOI: 10.1371/journal.pone.0207935.].

resumo Este capítulo apresenta uma visão geral da paleobiodiversidade alfa de Angola com base no registo fóssil disponível, o qual se limita às rochas sedimentares, a sua idade variando entre o Pré-Câmbrico e o pre-sente. O período geológico com a maior paleobiodiversidade no registo fóssil angolano é o Cretácico, com mais de 80% do total dos táxon...

Material from a minimum of twenty-nine individuals of a new ornithopod, represented by nearly every skeletal element, was recovered from the Proctor Lake locality in the Twin Mountains Formation (Aptian) of north-central Texas. This material includes various ontogenetic stages, providing insight into the growth patterns of this species. The new orn...

Measurements of femora used in growth regression. (XLSX)

Character descriptions. (DOC)

Ontogenetic features. (XLSX)

Scored character matrix. (XLSX)

Characters rescored for Tenontosaurus dossi. (XLSX)

Map of selected major skeletal elements of 2DU fossil locality from Proctor Lake, Texas. (DOCX)

Thin Sections of C. marri femora. (DOCX)

This chapter provides an overview of the alpha paleobiodiversity of Angola based on the available fossil record that is limited to the sedimentary rocks, ranging in age from Precambrian to the present. The geological period with the highest paleobiodiversity in the Angolan fossil record is the Cretaceous, with more than 80% of the total known fossi...

A braincase of the Cretaceous titanosaurian sauropod Malawisaurus dixeyi, complete except for the olfactory region, was CT scanned and a 3D rendering of the endocast and inner ear was generated. Cranial nerves appear in the same configuration as in other sauropods, including derived features that appear to characterize titanosaurians, specifically,...

In order to test for paleoenvironmental and paleoecological parameters important in dinosaur evolution, thirty-four fragments of dinosaur eggshell, paleosol carbonates from six localities, and calcite crystals from inside a dinosaur femur were collected from the Campanian to Maastrichtian Baruungoyot and Nemegt formations, Gobi Desert, Mongolia. Th...

A new stem cheloniid turtle, Cabindachelys landanensis, gen. et sp. nov., is represented by a nearly complete skull and partial hyoid collected in lower Paleocene shallow marine deposits, equivalent to the offshore Landana Formation, near the town of Landana in Cabinda, Angola. A partial chelonioid carapace previously reported from this locality is...

A theropod tracksite was discovered in the Nemegt Formation (Maastrichtian) at Bügiin Tsav, Mongolia by the Korea-Mongolia International Dinosaur Project in 2009. A total of 67 tracks (14 trackways [one didactylous, 13 tridactylous] and 12 isolated tracks) belonging to four ichnomorphotypes were mapped on a single horizon. This indicates at least f...

The early late Miocene is an interval of increased diversification for murine rodents. Whereas the genus Progonomys became widespread throughout Eurasia by 10 Ma, it appears from the known paleontological record that southern Asia is the arena of evolution and diversification at the base of the Murinae. The Siwalik fossil record of the Potwar Plate...

Abstract: The early late Miocene is an interval of increased diversification for murine rodents. Whereas the genus Progonomys became widespread throughout Eurasia by 10 Ma, it appears from the known paleontological record that southern Asia is the arena of evolution and diversification at the base of the Murinae. The Siwalik fossil record of the Po...

We report a new chelonioid turtle on the basis of a nearly complete skull collected in lower Paleocene, shallow marine deposits, equivalent to the offshore Landana Formation, near the town of Landana in Cabinda Province, Angola. Chelonioid material previously reported from this locality is likely referable to this new taxon. The well-preserved skul...

The separation of Africa from South America and the growth of the South Atlantic are recorded in rocks exposed along the coast of Angola. Tectonic processes that led to the formation of Africa as a continent also controlled sedimentary basins that preserve fossils. The vertebrate fossil record in Angola extends from the Triassic to the Holocene and...

Carbon isotope analysis of paleosol carbonates is one of the most widely used methods for producing quantitative estimates of CO2 levels in the ancient atmosphere, and is increasingly used to estimate soil pCO2 as a proxy for primary productivity. Recent efforts to improve the carbonate CO 2 paleobarometer by refining input parameters (e.g., soil t...

Fieldwork in the Maastrichtian of Angola, Morocco, and Jordan has yielded new specimens of the enigmatic mosasaur “Platecarpus” ptychodon, a form named on the basis of isolated teeth from Morocco. The new material includes articulated, associated, and isolated specimens from multiple individuals and reveals remarkable adaptations of the skull and p...

Background Ankylosaurs are one of the least explored clades of dinosaurs regarding endocranial anatomy, with few available descriptions of braincase anatomy and even less information on brain and inner ear morphologies. The main goal of this study is to provide a detailed description of the braincase and internal structures of the Early Cretaceous...

Derived members of the enigmatic mammalian order Desmostylia have molars comprising appressed columns whose morphology does not render their function in feeding simple to discern. Here we describe a new genus and species, Ounalashkastylus tomidai, more derived than Cornwallius but less derived than Desmostylus and Vanderhoofius, which develop a hyp...

A general lineage concept is widely adopted in studies of species delimitation for extant taxa with DNA sequence data. In the general lineage concept, species are separately evolving metapopulations that acquire sets of properties during the process of speciation. Murine rodents from the Miocene Siwalik Group of Pakistan have an excellent fossil re...

The Chiweta Beds of Malawi have yielded a diverse late Permian fossil tetrapod fauna that correlates with that of the Cistecephalus Assemblage Zone of the South African Karoo Supergroup. Amongst the fossil therapsids from the Chiweta Beds is the well-preserved skull and lower jaw of a burnetiamorph, a group of biarmosuchians with numerous bosses an...

Time calibration derived from the fossil record is essential for molecular phylogenetic and evolutionary studies. Fossil mice and rats, discovered in the Siwalik Group of Pakistan, have served as one of the best-known fossil calibration points in molecular phylogenic studies. Although these fossils have been widely used as the 12 Ma date for the Mu...

Significance Melanin is a widespread pigment that provides black to reddish brown hues to organisms. Recent evidence has shown that melanin is retained in exceptionally preserved fossils, including feathered dinosaurs, allowing the reconstruction of ancient color patterns. However, little is known about the chemical preservation of melanin or its d...

"The recent discovery of mammal tracks in the upper Aptian of Catoca (Lunda Sul, Angola) has triggered analysis of Mesozoic mammal morphotypes. About two dozen Mesozoic mammal track occurrences are known to date, often dubiously identified, mostly from Africa, a few from South and North America and Europe. [...]"

Timing and magnitude of vertical motions of the Earth’s crust is key to evaluate the impact of tectonic processes on changes in atmospheric circulation patterns, rainfall, and environmental conditions. The East African Plateau (EAP) is a major topographic feature that fundamentally impacts the patterns of the Indian-African Monsoon and the eastward...

Significance An enigmatic fossil representing the deep-diving, open-ocean whale family Ziphiidae found 740 km inland and at 620 m elevation in West Turkana, Kenya was rediscovered after it went missing for more than 30 years. This stranded whale fossil provides the first constraint on the initiation of east African uplift from near sea level at 17...

Timing and magnitude of surface uplift are key to understanding the impact of crustal deformation and topographic growth on atmospheric circulation, environmental conditions, and surface processes. Uplift of the East African Plateau is linked to mantle processes, but paleoaltimetry data are too scarce to constrain plateau evolution and subsequent v...

ABSTRACT Stable oxygen isotope values of inoceramid marine bivalve shells recovered from Bentiaba, Angola, are utilised as a proxy for paleotemperatures during the Late Cretaceous development of the African margin of the South Atlantic Ocean. The δ18O values derived from inoceramids show a long-term increase from –3.2‰ in the Late Turonian to value...

We report here a new elasmosaurid from the early Maastrichtian at Bentiaba, southern Angola. Phylogenetic analysis places the new taxon as the sister taxon to Styxosaurus snowii, and that clade as the sister of a clade composed of (Hydrotherosaurus alexandrae (Libonectes morgani + Elasmosaurus platyurus)). The new taxon has a reduced dorsal blade o...

Deciphering the timing and magnitude of vertical crustal motions is key to understanding the impact of tectonic uplift on changes in atmospheric circulation, rainfall, and environmental conditions. Uplift of the East African Plateau (EAP) of Kenya has been linked to mantle processes, but paleoaltimetry data are still too scarce to unambiguously con...

Marzola M., Mateus O., Schulp A.S., Jacobs L.L., Polcyn M.J., & Pervov V. 2014. Early Cretaceous tracks of a large mammaliamorph, a crocodilomorph, and dinosaurs from an Angolan diamond mine. Journal of Vertebrate Paleontology, Program and Abstracts, 2014, p. 181. *Selected as featured abstract for the 2014 SVP Meeting

During the 1964 Harvard West Turkana Expedition to Loperot, Kenya, a fossil beaked whale skull fragment (KNM-LP 52956) was discovered by James G. Mead. Ziphiid whales are deep-diving odontocetes, which occasionally enter rivers, such as the 2006 example of the Thames whale (Hyperoodon ampullatus) in the City of London. However, this ziphiid specime...

We present the δ13C and paleomagnetic stratigraphy for marine strata at the coast of southern Angola, anchored by an intercalated basalt with a whole rock 40Ar/39Ar radiometric age of 84.6 ± 1.5 Ma, being consistent with both invertebrate and vertebrate biostratigraphy. This is the first African stable carbon isotope record correlated to significan...

The Bench 19 Bonebed at Bentiaba, Angola, is a unique concentration of marine vertebrates preserving six species of mosasaurs in sediments best correlated by magnetostratigraphy to chron C32n.1n between 71.4 and 71.64 Ma. The bonebed formed at a paleolatitude near 24°S, with an Atlantic width at that latitude approximating 2700 km, roughly half tha...

Past ecological responses of mammals to climate change are recognized in the fossil record by adaptive significance of morphological variations. To understand the role of dietary behavior on functional adaptations of dental morphology in rodent evolution, we examine evolutionary change of tooth shape in late Miocene Siwalik murine rodents, which ex...

Ziphiid whales are deep diving odontocetes, which occasionally enter rivers, such as the 2006 example of the Thames whale (Hyperoodon ampullatus). Their fossil record in Africa derives mainly from specimens dredged off the South African coast, with the notable exception of a skull fragment discovered by the 1964 Harvard expedition to Loperot, West...

Stable carbon isotope analysis in tooth enamel is a well-established approach to infer C3 and C4 dietary composition in fossil mammals. The bulk of past work has been conducted on large herbivorous mammals. One important finding is that their dietary habits of fossil large mammals track the late Miocene ecological shift from C3 forest and woodland...

Isotope compositions in a sequence of molars from m1 to m3 from three mandibles (#1 to #3) of Recent Rattus sp. (A) δ13C data. (B) δ18O data. Specimens were analyzed in the same analytical run except m1 of #1 and #3, which were run four days after the others. All were right molars except m2 of #2. (PDF)

SEM images of m1 of laboratory Mus musculus, which are treated by 0.1 M acetic acid. The m1specimens were provided by the University of Texas, Southwestern Medical Center. Individuals were sacrificed for a research purpose unrelated to this study. (PDF)

Scatter plot of van Dam's [30] index vs. time, ranging from 9.2 to 6.5 Ma, between Karnimata and the “Progonomys clade”. (PDF)

Scatter plot of hypsodonty vs. time, ranging from 9.2 to 6.5 Ma, between Karnimata and the “ Progonomys clade”. (PDF)

Scatter plot of δ13C data vs. time, ranging from 9.2 to 6.5 Ma, between Karnimata and the “ Progonomys clade”. (PDF)

Key to names of Siwalik murine species used in this study in comparison to Jacobs and Flynn [29]. Major species are those known by five or more specimens of the upper first molars (M1). Minor species are those known by less than five specimens of M1. (PDF)

Results of ANCOVA between Karnimata and the “Progonomys clade”. Asterisks for p<0.05. (PDF)

Summary of linear regression analysis for δ13C values, VD index, and hypsodonty. Asterisks for p<0.05. (PDF)

Means of hypsodonty measurements with 95 % bootstrap confidence intervals. Asterisks indicate hypsodonty values measured in specimens in wear stage III of Lazzari et al. [35]. (PDF)

Full data of m1 specimens analyzed in this study, including dental measurements, δ13C values, and the side of teeth from which isotope data were taken. The δ13C values are corrected to be consistent with the H3PO4 method using the laser-H3PO4 offset of modern beaver incisor in every run. Specimens from YGSP 182 treated by 0.1 M acetic acid instead...

Full data of M1 specimens of Siwalik murines from the Potwar Plateau, including dental measurements, van Dam's [30] index, and hypsodonty values. Abbreviations: lap, distance between the posterior side of the lingual anterocone and that of protocone (see Figure 3C); VD, van Dam's [30] index; Hy, hypsodonty. (TXT)

Results of statistical tests for carbon isotope data in coexisting species at 7.4 Ma, 6.5 Ma, and Recent. Asterisks for p<0.05. Abbreviations: WA, Welch's ANOVA; MW, Mann-Whitney U test. (PDF)

Means of VD index with 95 % bootstrap confidence intervals. (PDF)