A New Horned Crocodile from the Plio-Pleistocene Hominid Sites at Olduvai Gorge, Tanzania

BACKGROUND: The fossil record reveals surprising crocodile diversity in the Neogene of Africa, but relationships with their living relatives and the biogeographic origins of the modern African crocodylian fauna are poorly understood. A Plio-Pleistocene crocodile from Olduvai Gorge, Tanzania, represents a new extinct species and shows that high crocodylian diversity in Africa persisted after the Miocene. It had prominent triangular "horns" over the ears and a relatively deep snout, these resemble those of the recently extinct Malagasy crocodile Voay robustus, but the new species lacks features found among osteolaemines and shares derived similarities with living species of Crocodylus. METHODOLOGY/PRINCIPAL FINDINGS: The holotype consists of a partial skull and skeleton and was collected on the surface between two tuffs dated to approximately 1.84 million years (Ma), in the same interval near the type localities for the hominids Homo habilis and Australopithecus boisei. It was compared with previously-collected material from Olduvai Gorge referable to the same species. Phylogenetic analysis places the new form within or adjacent to crown Crocodylus. CONCLUSIONS/SIGNIFICANCE: The new crocodile species was the largest predator encountered by our ancestors at Olduvai Gorge, as indicated by hominid specimens preserving crocodile bite marks from these sites. The new species also reinforces the emerging view of high crocodylian diversity throughout the Neogene, and it represents one of the few extinct species referable to crown genus Crocodylus

Los Batanes: A trap for the Pyrenean wild goat during the Late Pleistocene (Spain)

Los Batanes cave (1025 m.a.s.l.) is a karstic system formed by pressure ducts, near the locality of Biescas in the Upper Gallego Valley (Huesca, Spain). Many fossil remains were retrieved from the cave sediments. The minimum sediment calendar age was determined to be 12.770 ± 60 BP. This date indicates that the deposit was formed before the Late Pleistocene-Early Holocene transition at the Pyrenees. Here we analyze the faunal assemblage of the site that is only conformed by remains of Pyrenean wild goat (Capra pyrenaica pyrenaica), which is a recently extinct subspecies of Iberian wild goat (C. pyrenaica). In the site, 1079 remains of Iberian wild goat have been recovered being one of the most numerous both in minimum number of individuals (MNI) and number of identified specimens (NISP) recovered until now in a natural trap in the Spanish Pyrenees. The population of Los Batanes shows a wide range of ages between juvenile and senile individuals and the MNI estimated from the number of right metatarsus is nine. The taphonomic features indicate that the cave acted as a trap for the goats which inhabited the vicinity of the cave. These goats probably stumbled and fell to the bottom of the pit and they could not get out, dying inside. Due to the origin of the accumulation numerous complete bones have been recovered. These fossil allow us to perform a biometric analysis that indicates that population of Los Batanes is in the range size of other goats from Late Pleistocene of Iberian Peninsula

Using Striated Tooth Marks on Bone to Predict Body Size in Theropod Dinosaurs: A Model Based on Feeding Observations of Varanus Komodoensis, the Komodo Monitor

Mesozoic tooth marks on bone surfaces directly link consumers to fossil assemblage formation. Striated tooth marks are believed to form by theropod denticle contact, and attempts have been made to identify theropod consumers by comparing these striations with denticle widths of contemporaneous taxa. The purpose of this study is to test whether ziphodont theropod consumer characteristics can be accurately identified from striated tooth marks on fossil surfaces. We had three major objectives (1) to experimentally produce striated tooth marks and explain how they form; (2) to determine whether body size characteristics are reflected in denticle widths; and (3) to determine whether denticle characters are accurately transcribed onto bone surfaces in the form of striated tooth marks. We conducted controlled feeding trials with the dental analogue Varanus komodoensis (the Komodo monitor). Goat (Capra hircus) carcasses were introduced to captive, isolated individuals. Striated tooth marks were then identified, and striation width, number, and degree of convergence were recorded for each. Denticle widths and tooth/body size characters were taken from photographs and published accounts of both theropod and V. komodoensis skeletal material, and regressions were compared among and between the two groups. Striated marks tend to be regularly striated with a variable degree of branching, and may co-occur with scores. Striation morphology directly reflects contact between the mesial carina and bone surfaces during the rostral reorientation when defleshing. Denticle width is influenced primarily by tooth size, and correlates well with body size, displaying negative allometry in both groups regardless of taxon or position. When compared, striation widths fall within or below the range of denticle widths extrapolated for similar-sized V. komodoensisindividuals. Striation width is directly influenced by the orientation of the carina during feeding, and may underestimate but cannot overestimate denticle width. Although body size can theoretically be estimated solely by a striated tooth mark under ideal circumstances, many caveats should be considered. These include the influence of negative allometry across taxa and throughout ontogeny, the existence of theropods with extreme denticle widths, and the potential for striations to underestimate denticle widths. This method may be useful under specific circumstances, especially for establishing a lower limit body size for potential consumers

Table S3

Dental crown morphometrics for theropod fossil specimen

Table S4

A listing of all Varanus komodoensis striated tooth marks collected

Data from: Using striated tooth marks on bone to predict body size in theropod dinosaurs: a model based on feeding observations of Varanus komodoensis, the Komodo monitor

Mesozoic tooth marks on bone surfaces directly link consumers to fossil assemblage formation. Striated tooth marks are believed to form by theropod denticle contact, and attempts have been made to identify theropod consumers by comparing these striations with denticle widths of contemporaneous taxa. The purpose of this study is to test whether ziphodont theropod consumer characteristics may be accurately identified from striated tooth marks on fossil surfaces. There are three major objectives; 1) experimentally produce striated tooth marks and explain how they form; 2) determine whether body size characteristics are reflected in denticle widths; 3) determine whether denticle characters are accurately transcribed onto bone surfaces in the form of striated tooth marks. Controlled feeding trials were conducted with the dental analogue Varanus komodoensis (the Komodo monitor). Goat (Capra hircus) carcasses were introduced to captive, isolated individuals. Striated tooth marks were then identified, and striation width, number, and degree of divergence were recorded for each. Denticle widths and tooth/body size characters were taken from photographs and published accounts of both theropod and V. komodoensis skeletal material, and regressions were compared among and between the two groups. Striated marks tend to be regularly striated with a variable degree of branching, and may co-occur with scores. Striation morphology directly reflects contact between the mesial carina and bone surfaces during the rostral reorientation when defleshing. Denticle width is primarily influenced by tooth size, and correlates well with body size displaying negative allometry in both groups regardless of taxon or position. When compared, striation widths fall within or below the range of denticle widths extrapolated for similar sized V. komodoensis individuals. Striation width is directly influenced by the orientation of the carina during feeding, and may underestimate but cannot overestimate denticle width. Although body size may theoretically be estimated solely by a striated tooth mark under ideal circumstances, many caveats should be considered. These include the influence of negative allometry across taxa and throughout ontogeny, the existence of theropods with extreme denticle widths, and the potential for striations to underestimate denticle widths. This method may be useful under specific circumstances, especially for establishing a lower limit body size for potential consumers

Table S3

Dental crown morphometrics for theropod fossil specimen

Table S1

Crown morphometrics for Varanus komodoensis dry skull specimen