James O Farlow

• Indiana University – Purdue University Fort Wayne

Modern crocodylians—crocodiles, alligators, caiman (Central and South America), and gharials (India)—have evolved over 250 million years from a fully terrestrial, bipedal ancestor. Along with birds, crocodylians are the only living members of Archosauria, the group including nonavian dinosaurs. Ruling Reptiles features contributions on a broad ran...

(Feb. 5, 2023). UPDATED. Now includes two programs to estimate Body Mass (MBd) from TL (total length). One equation is based on a sample size of N=38; the other on a sample size of N=51). This is an unpublished supplement to Hurlburt et al. (2003). It is an Excel file permitting estimates of Body Mass (MBd), Total Length (TL), and Snout Vent Length...

Dinosaur footprints often occur in Late TriassicEarly Jurassic continental sedimentary rocks. While many such tracks can readily be associated with the kinds of dinosaurs that made them, the makers of some footprints have been controversial. Large tridactyl (three-toed) footprints of the ichnogenus Eubrontes are thought by most paleontologists to h...

Counts of the number of skeletal specimens of “adult” megaherbivores and large theropods from the Morrison and Dinosaur Park formations—if not biased by taphonomic artifacts—suggest that the big meat‐eaters were more abundant, relative to the number of big plant‐eaters, than one would expect on the basis of the relative abundance of large carnivore...

The end-Triassic mass extinction events mark a pivotal period in archosaur history, and have been proposed to contribute to the rise and dominance of dinosaurs throughout the Mesozoic. In southern Africa, the Triassic–Jurassic boundary is contained within the richly fossiliferous fluvio-lacustrine-aeolian deposits of the upper Stormberg Group in th...

The dinosaur track record features numerous examples of trackways with elongated metatarsal marks. Such ‘elongate tracks’ are often highly variable and characterized by indistinct outlines and abbreviated or missing digit impressions. Elongate dinosaur tracks are well-known from the Paluxy River bed of Texas, where some have been interpreted as ‘ma...

Constraints of time, personnel, and financial resources made it necessary to devise a system for rapid, salvage screen-washing of a heterogeneous mixture of unconsolidated fossiliferous sediments and intermixed, unrelated sediments from a Neogene continental sinkhole site in northern Indiana, USA. We constructed three sets of an apparatus that used...

The morphology of fossil footprints is the basis of vertebrate footprint ichnology. However, the processes acting during and after trace fossil registration which are responsible for the final morphology have never been precisely defined, resulting in a dearth of nomenclature. Therefore, we discuss the concepts of ichnotaphonomy, ichnostratinomy, t...

In the last decades several new dinosaurs species have been described from both Laurasia and Gondwana and a complex, multi-dimensional picture of the physiology, evolution and behavior of dinosaurs has emerged. One of the central elements of new discoveries is the recognition of a complex sociality in this vertebrate clade, especially in herbivorou...

Late Neogene floras of North America are mainly represented by sites located along the east coast Piedmont and the Great Plains. To date, there are only two upper Neogene inland localities in the eastern half of North America, the Pipe Creek Sinkhole (Indiana) and the Gray Fossil Site (Tennessee). At both sites, a lacustrine environment was formed...

The transect from Jones Ranch Quarry, west of the town of Glen Rose, to the Arlington Archosaur Site, in the heart of the Dallas-Fort Worth Metroplex, spans 20 million years of the middle Cretaceous. These sediments lie at the base of a larger section in north-central Texas with near continuous sedimentation to the end of the Maastrichtian. At an e...

Fossil bone microanalyses reveal the ontogenetic histories of extinct tetrapods, but incomplete fossil records often result in small sample sets lacking statistical strength. In contrast, a histological sample of 50 tibiae of the hadrosaurid dinosaur Maiasaura peeblesorum allows predictions of annual growth and ecological interpretations based on m...

Literature concerning dinosaur footprints or trackways exhibiting abnormal gait or morphology reflecting pathology (ichnopathology) is rare. We report on a number of Jurassic and Cretaceous occurrences of theropod footprints from western North America with unusual morphologies interpreted herein as examples of inferred pathologies, or ichnopatholog...

Diplocraterion, a U-shaped burrow attributed to infaunal invertebrates, is normally a shallow-marine trace fossil and not part of a continental vertebrate ichnoassemblage. Hence, the Glen Rose Formation (Aptian-Albian) of Texas (USA) presents an opportunity to study Diplocraterion associated with a world-class dinosaur tracksite. Most Diplocraterio...

The skeletal record of tyrannosaurids is well-documented, whereas their footprint record is surprisingly sparse. There are only a few isolated footprints attributed to tyrannosaurids and, hitherto, no reported trackways. We report the world’s first trackways attributable to tyrannosaurids, and describe a new ichnotaxon attributable to tyrannosaurid...

Vertebrate ichnology has usually been based on qualitative descriptions of specimens, from its beginning (e .g. Hitchcock 1836) to the most recent papers (e.g . Milàn, 2011; Lockley et al. 2012). At the same time, considerable effort has gone into illustrating footprint and trackway morphological features (e.g. Thulborn 1990). In recent years, new...

Bone microanalyses of extant vertebrates provide a necessary framework from which to form hypotheses regarding the growth and skeletochronology of extinct taxa. Here, we describe the bone microstructure and quantify the histovariability of appendicular elements and osteoderms from three juvenile American alligators (Alligator mississippiensis) to a...

The crocodile-line basal suchian Poposaurus gracilis had body proportions suggesting that it was an erect, bipedal form like many dinosaurs, prompting questions of whether its pedal proportions, and the shape of its footprint, would likewise "mimic" those of bipedal dinosaurs. We addressed these questions through a comparison of phalangeal, digital...

It is inevitable that some important specimens will become lost or damaged over time, conservation is therefore of vital importance. The Paluxy River dinosaur tracksite is among the most famous in the world. In 1940, Roland T. Bird described and excavated a portion of the site containing associated theropod and sauropod trackways. This excavated tr...

The dinosaur tracks of the Glen Rose Formation in the Paluxy River at Dinosaur Valley State Park are among the best preserved and most abundant in the world. Although many tracksites are easily correlated to the Main Tracksite, others, especially those at the extreme ends of the park, are differently preserved and not obviously correlated. To count...

The extent to which the makers of tridactyl dinosaur footprints can be identified depends on the extent to which their foot skeletons can be told apart. We examined this question for non-avian theropod dinosaurs (NATs) and large ground birds, making additional comparisons with functionally tridactyl, bipedal – or potentially bipedal – ornithischian...

Terra Nova, 24, 136–141, 2012 Theropod dinosaur footprints at the Costalomo tracksite (Pinilla de los Moros Formation, Upper Hauterivian–Lower Barremian, western Cameros Basin, Salas de los Infantes, Burgos Province, Spain) show unusual preservation of a previously undescribed nature. The footprints occur as casts (positive epireliefs) at the top o...

In 1940 R.T. Bird of the American Museum of Natural History collected segments of a sauropod and a theropod trackway from a site in the bed (Glen Rose Formation; Lower Cretaceous) of the Paluxy River, in what is now Dinosaur Valley State Park (Glen Rose, Texas, USA). However, Bird left undocumented thousands of other dinosaur footprints from this a...

A single specimen, part and counterpart of a carapace, of a horseshoe crab from the Lower Cretaceous (Albian) Glen Rose Formation in north‐central Texas, forms the basis for the definition of a new genus and species, Crenatolimulus paluxyensis. The discovery represents only the fifth limuline known from the Cretaceous. Its preservational style is r...

An external fundamental system (EFS) is a form of bone microstructure present in the outermost cortex of long bones in animals that have attained skeletal maturity. It indicates an effective cessation of any significant periosteal growth (i.e., growth in circumference or girth). Although an EFS has been noted in several reptile taxa, the idea that...

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 kind...

X-ray computed tomography and petrographic thin sectioning were used to study internal features of the plates of the thyreophoran dinosaur Stegosaurus and the osteoderms of Alligator. Infrared thermographic imaging of basking caimans was used to examine possible differential blood flow to osteoderms and other parts of the skin. Multiple large openi...

Screen-washing of unconsolidated fossiliferous sediments from the late Neogene Pipe Creek Sinkhole (Grant County, Indiana) yielded two coprolites. Maximum preserved diameter of both is about 26 mm, and both are apatitic in composition. Although one coprolite is largely amorphous internally, the other preserves remnants of hair and at least two teet...

Public engagement and the promotion of science to a wider non-academic audience form an integral role of the professional scientist in the twenty-first century. The high level of public interest in palaeontology means that the Earth's prehistoric past can provide an important medium through which to communicate information concerning contemporary s...

The Late Neogene represents warm Earth conditions immediately prior to the development of extensive northern hemisphere glaciation, and this period in Earth history may therefore provide the best available analog for the projected outcome of continued global warming. There are few interior continental sites of Late Neogene age from the eastern half...

The Early Pliocene is a critical period in Earth history, representing warm Earth conditions immediately prior to the development of extensive northern hemisphere glaciation. It thus may provide the best available analog for predicting the climate changes associated with continued global warming. Unfortunately, there are few interior continental re...

Total length, snout-vent length, and body mass are tightly correlated with length and other dimensions of the femur in Alligator mississippiensis. American alligator-based equations relating total length and body mass to femoral dimensions predict the sizes of other extant crocodylian species reasonably well, suggesting that alligator-based relatio...

Total length, snout-vent length, and body mass are tightly correlated with length and other dimensions of the femur in Alligator mississippiensis. American alligator-based equations relating total length and body mass to femoral dimensions predict the sizes of other extant crocodylian species reasonably well, suggesting that alligator-based relatio...

The mid-thigh circumference of the intact hindlimb in Alligator mississippiensis is tightly correlated with transverse dimensions of the proximal and distal articular surfaces of the femur, and with minimum midshaft femoral circumference. Maximum diameter of the proximal articular end, width across the distal articular end, and midshaft circumferen...

La mayor parte de loa rastros de Dinosaurio y sus calcos, de la Formación Berilo Este (Jurásico inferior) del Parque Estatal de Dinosaurios, Rocky Hill, Connecticut, se encuentran a techo de los estratos. Las huellas pertenecen al icongénero Eubrontes y,o a grandes Anchisaunpus, y probablemente fueron hechas por dinosaurios teró- podos. No hay ning...

Body size (total length or body mass) is tightly correlated with femoral dimensions (length or minimum midshaft circumference) in the American alligator (Alligator mississippiensis). Regression equations of body size against femoral dimensions for alligators satisfactorily predict the body size of other species of extant crocodylians, indicating th...

Phytosaurs were the largest and most common semi-aquatic predators of the Late Triassic. Although their skulls are relatively common in the fossil record, articulated, or even associated skeletons are extremely rare, so it has always been difficult to gauge just how large (mass or length) an individual phytosaur may have been. Body mass in particul...

The conceptual leap from fossil footprint to biological trackmaker is necessary in paleoecological interpretations based on ichnotaxa. Such interpretations require confidence in the trackmaker's identity. Trackmakers currently are postulated generally through the comparison of gross footprint shapes with modern animals or with pedal skeletons of mo...

Phytosaurs were the largest and most common semi-aquatic predators of the Late Triassic. Although their skulls are relatively common in the fossil record, articulated, or even associated skeletons are extremely rare, so it has always been difficult to gauge just how large (mass or length) an individual phytosaur may have been. Body mass in particul...

Record flooding in late June 1997 in south central Texas exposed dinosaur footprints on the Boerne Lake spillway near Boerne, Texas. At least three trackways are present in the upper portion of Unit No. 3 of the Lower Cretaceous Glen Rose Formation. This sequence represents a period of high-frequency depositional cyclicity on a very shallow and par...

Spermophilus cf. howelli, Spermophilus sp., Castor or Dipoides sp., Geomys cf. adamsi, Symmetrodontomys daamsi, sp. nov., Bensonomys hershkovitzi, sp. nov., Ogmodontomys pipecreekensis, sp. nov., and Pliophenacomys koenigswaldi n. sp. are reported from the Pipe Creek Sinkhole of Grant County, Indiana. The Geomys sample demonstrates a variable sulcu...

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Quarrying in east-central Indiana has uncovered richly fossiliferous unconsol-idated sediment buried beneath Pleistocene glacial till. The fossiliferous layer is part of a sedimentary deposit that accumulated in a sinkhole developed in the limestone flank beds of a Paleozoic reef. Plant and animal (mostly vertebrate) remains are abundant in the fos...

Predatory theropod dinosaurs can usually be identified as such by features of their jaws, teeth, and postcrania, but different clades of these reptiles differed in their adaptations for prey handling. Inferences about theropod diets and hunting behavior based on functional morphology are sometimes supported by evidence from taphonomic associations...

Modern birds have markedly foreshortened tails and their body mass is centred anteriorly, near the wings. To provide stability during powered flight, the avian centre of mass is far from the pelvis, which poses potential balance problems for cursorial birds. To compensate, avians adapted to running maintain the femur subhorizontally, with its dista...

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Theropod (carnivorous) dinosaurs spanned a range from chicken-sized to elephant-sized animals. The primary mode of locomotion in these dinosaurs was fairly conservative: Theropods were erect, digitigrade, striding bipeds. Even so, during theropod evolution there were changes in the hip, tail, and hindlimb that undoubtedly affected the way these din...

Theropod (carnivorous) dinosaurs spanned a range from chicken-sized to elephant-sized animals. The primary mode of locomotion in these dinosaurs was fairly conservative: Theropods were erect, digitigrade, striding bipeds. Even so, during theropod evolution there were changes in the hip, tail, and hindlimb that undoubtedly affected the way these din...

To what extent does ichnological diversity (the number of distinctive trace fossil morphologies) serve as a proxy for zoological diversity (species richness of trackmakers in the living fauna) in footprint assemblages made by terrestrial lower vertebrates? This question was investigated in a study of body form and trackway features of monitor lizar...

To what extent does ichnological diversity (the number of distinctive trace fossil morphologies) serve as a proxy for zoological diversity (species richness of trackmakers in the living fauna) in footprint assemblages made by terrestrial lower vertebrates? This question was investigated in a study of body form and trackway features of monitor lizar...

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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 car...

SYNOPSIS. Theropod (carnivorous) dinosaurs spanned a range from chicken-sized to elephant-sized animals. The primary mode of locomotion in these dinosaurs was fairly conservative: Theropods were erect, digitigrade, striding bipeds. Even so, during theropod evolution there were changes in the hip, tail, and hindlimb that undoubtedly affected the way...

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We describe a new life restoration of Tyrannosaurus rex, based on a fairly complete skeleton (Museum of the Rockies [MOR] 555). From the volume of this model, we estimate the live mass of the full-sized dinosaur as approximately 6,000 kg. Because MOR 555 is a representative of the gracile morph of T. rex, the mass of the robust morph may have been...

Tyrannosaurs and other large carnivorous dinosaurs were probably opportunistic flesh‐eaters, both attacking live prey and also consuming carrion. As tall bipeds, tyrannosaurs may have been better able to locate carcasses than were their shorter contemporaries. By carrying their heads well off the ground, tyrannosaurs may have been able to spot dead...