In their recent publication on an overview of theropod discoveries and classification, Hendrickx and colleagues mistakenly attributed the earliest historical reports of non-avian theropods in North America and South America to Joseph Leidy in 1856 and Florentino Ameghino in 1899, respectively. Yet, theropod tracks from Massachusetts had already been reported by Hitchcock in 1836, and […]
Differentiation of tooth size and shape within the jaw (i.e. heterodonty) is an expected pattern in the majority of Neoselachii sharks. Various forms of heterodonty may be observed within an individual set of jaws, which can be the result of tooth position (monognathic), upper or lower jaw position (dignathic), tooth file or developmental position (ontogeny), […]
Theropods form a taxonomically and morphologically diverse group of dinosaurs that include extant birds. Inferred relationships between theropod clades are complex and have changed dramatically over the past thirty years with the emergence of cladistic techniques. Here, we present a brief historical perspective of theropod discoveries and classification, as well as an overview on the […]
A diverse vertebrate assemblage was recovered from the Eutaw Formation along a stretch of Luxapalila Creek in Lowndes County, Mississippi. The assemblage is dominated by elasmobranchs but also includes osteichthyans (seven species), archosaurs (one crocodilian, two dinosaurs), and turtles (trionychid and chelonioid). Twenty one elasmobranch taxa were identified (14 selachians and seven batoids), including new species […]
PalArch’s Journal of Vertebrate Palaeontology, 11(1) (2014) Perhaps the greatest treasures in paleontology are not individual skeletons of spectacular dinosaurs, but the incredible treasure troves of fossils from the famous “Mother Lode” deposits of fossils known as Lagerstätten. There are about a dozen or so such famous localities around the world, where the fossils have […]
PalArch’s Journal of Vertebrate Palaeontology, 10(6) (2013) I have one vivid memory from my summer vacation between the 2nd and 3rd grade – discovering a ragged and faded copy of All About Strange Beasts of the Past by Roy Chapman Andrews at a neighbor’s garage sale. To me, the most exciting chapter of this elementary-level […]
An extinct feline ecomorph Hoplophoneus was afflicted with a congenital anomaly (hemivertebra) not previously observed in cats and not previously reported in fossil mammals. The position of the hemivertebrae provided little opportunity for other cervical vertebrae to compensate for the resultant 40-degree deformity. Download PDF File
The American bison are traditionally thought of as animals of the vast plains and grasslands, but paleontological and archaeological evidence supports the view that the biogeographic range of bison extended throughout the continental United States to include the American Southwest and Arizona. During the Pleistocene (2,588,000 BP to 11,700 BP), there are several paleontological and […]
The Upper Jurassic Morrison Formation of western North America has yielded a number of specimens assigned to the ornithischian dinosaurs Stegosaurus and Camptosaurus, and many of these specimens come from channel sandstone deposits. Six new specimens are recorded mostly from channel sandstones as well. Indeed, early analyses of site occurrences (reducing the effects of large […]
An isolated bone from the late Campanian-aged Kaiparowits Formation of southern Utah is tentatively identified as the terminal wing phalanx (manual phalanx IV-4) from a pterosaur, representing the first report of this clade from the formation. The specimen is 60 mm long and hollow, with thin and delicate walls and expanded ?proximal and ?distal ends. This is consistent with anatomy reported for equivalent elements in pterodactyloid pterosaurs. Although the specimen cannot be more precisely identified, it is consistent with occurrences of pterosaurs in penecontemporaneous terrestrial depositional environments throughout western North America.
It has recently been argued that neural spine bifurcation increases through ontogeny in several Morrison Formation sauropods, that recognition of ontogenetic transformation in this ‘key character’ will have sweeping implications for sauropod phylogeny, and that Suuwassea and Haplocanthosaurus in particular are likely to be juveniles of known diplodocids. However, we find that serial variation in sauropod vertebrae can mimic ontogenetic change and is therefore a powerful confounding factor, especially when dealing with isolated elements whose serial position cannot be determined. When serial position is taken into account, there is no evidence that neural spine bifurcation increased over ontogeny in Morrison Formation diplodocids. Through phylogenetic analysis we show that neural spine bifurcation is not a key character in sauropod phylogeny and that Suuwassea and Haplocanthosaurus are almost certainly not juveniles of known diplodocids. Skeletochronology based on the sequence of skeletal fusions during ontogeny can provide relative ontogenetic ages for some sauropods. Although such data are sparsely available to date and often inconsistent among sauropod genera they provide another line of evidence for testing hypotheses of ontogenetic synonymy. Data from skeletal fusions suggest that Suuwassea and Haplocanthosaurus are both valid taxa and that neither is an ontogenetic morph of a known diplodocid.
Abstract A summary of museum and literature records of ground sloths collected from South Carolina is presented. The ground sloth record in South Carolina consists of three genera, Eremotheirum with two species, Megalonyx with three species and Paramylodon with one species. Three of these species, Eremotherium eomigrans and Megalonyx leptostomus from the Blancan and Megalonyx […]
Abstract A new species of tinamou from the early-middle Miocene (Santacrusian), Santa Cruz Formation of Argentina is named. The new species is approximately 16 million year old and has an affinity with the modern genus Crypturellus based on the unique characteristics of the humerus, hence, the designation aff. Crypturellus. Fossil species and the zooarchaeological record […]
Abstract The Eocene Green River and Bridger Formations of Wyoming represent lacustrine and fluvial environments noteworthy for an extremely diverse crocodylian fauna (at least eight species in seven genera). This paper discusses a fragmentary crocodylian jaw from the Bridger Formation, and also notes possible ecological partitioning among these sympatric crocodylians. The jaw fragment can be assigned confi dently to […]
Abstract Climate change at the Paleocene-Eocene Thermal Maximum (PETM) is frequently regarded as among the best ancient proxies for the potential effects of modern climate change. Terrestrial sections recording this event are few, but essential in understanding the impacts of rapid global change on land-dwelling life forms such as humans. In the Hanna Formation, exposed in the Hanna Basin […]