Allometry and Paleoecology of Medial Miocene Dwarf Rhinoceroses from the Texas Gulf Coastal Plain

Paleobiology ◽  
1982 ◽  
Vol 8 (1) ◽  
pp. 16-30 ◽  
Author(s):  
Donald R. Prothero ◽  
Paul C. Sereno
Keyword(s):  
Body Size ◽  
Coastal Plain ◽  
Sympatric Species ◽  
High Plains ◽  
Gulf Coastal Plain ◽  
Canine Tooth ◽  
Positive Allometry ◽  
Mammalian Faunas ◽  
The Common ◽  
Limb Proportions

Barstovian (medial Miocene) mammalian faunas from the Texas Gulf Coastal Plain contained four apparently sympatric species of rhinoceroses: the common forms Aphelops megalodus and Teleoceras medicornutus, a dwarf Teleoceras, and a dwarf Peraceras. Previous work has suggested positive allometry in tooth area with respect to body size in several groups of mammals, i.e., larger mammals have relatively more tooth area. However, dwarfing lineages were shown to have relatively more tooth area for their body size. Our data show no significant allometry in post-canine tooth area of either artiodactyls or ceratomorphs. Similarly, dwarf rhinoceroses and hippopotami show no more tooth area than would be predicted for their size. Limbs are proportionately longer and more robust in larger living ceratomorphs (rhinos and tapirs) than predicted by previous authors. Limb proportions of both dwarf rhinoceroses and dwarf hippopotami are even more robust than in their living relatives.The high rhinoceros diversity reflects the overall high diversity of Barstovian faunas from the Texas Gulf Coastal Plain. The first appearance of several High Plains mammals in these faunas indicates “ecotone”-like conditions as faunal composition changed. Study of living continental dwarfs shows that there is commonly an ecological separation between browsing forest dwarfs and their larger forebears, which are frequently savannah grazers. This suggests that the dwarf rhinoceroses might have been forest browsers which were sympatric with the larger grazing rhinos of the High Plains during the Barstovian invasion. The continental dwarf model also suggests that insular dwarfism may be explained by the browsing food resources that predominate on islands.

Miocene rhinoceroses from the Texas Gulf Coastal Plain

1987 ◽  
Vol 61 (2) ◽  
pp. 388-423 ◽  
Author(s):  
Donald R. Prothero ◽  
Earl M. Manning
Keyword(s):  
New Species ◽  
North America ◽  
Coastal Plain ◽  
Middle Miocene ◽  
Early Miocene ◽  
High Plains ◽  
Gulf Coastal Plain ◽  
Local Fauna ◽  
Southeast Texas ◽  
A New Species

Four species of rhinoceros occur together in the Barstovian (middle Miocene) faunas of southeast Texas, a unique situation in the Miocene of North America. Two are assigned to normal contemporary High Plains species of Aphelops and Teleoceras, and two to dwarf species of Peraceras and Teleoceras. The dwarf Peraceras is a new species, P. hessei. The dwarf Teleoceras is assigned to Leidy's (1865) species “Rhinoceros” meridianus, previously referred to Aphelops. “Aphelops” profectus is here reassigned to Peraceras.The late Arikareean (early Miocene) Derrick Farm rhino, erroneously referred to “Caenopus premitis” by Wood and Wood (1937), is here referred to Menoceras arikarense. Menoceras barbouri is reported from the early Hemingfordian (early Miocene) Garvin Gully local fauna of southeast Texas. The rhinos from the early Clarendonian Lapara Creek Fauna are tentatively referred to Teleoceras cf. major.The three common genera of middle late Miocene rhinoceroses of North America (Aphelops, Peraceras, Teleoceras) are rediagnosed. Aphelops and Peraceras are more closely related to the Eurasian Aceratherium and Chilotherium (all four together forming the Aceratheriinae) than they are to the American Teleoceras. Contrary to Heissig (1973), Teleoceras is more closely related to the living rhinoceroses and their kin (together forming the Rhinocerotini) than it is to the Aceratheriinae.

scholarly journals The isotopic niche of Atlantic, biting marine mammals and its relationship to skull morphology and body size

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Massimiliano Drago ◽  
Marco Signaroli ◽  
Meica Valdivia ◽  
Enrique M. González ◽  
Asunción Borrell ◽  
...  
Keyword(s):  
Body Size ◽  
Atlantic Ocean ◽  
Fisheries Management ◽  
Marine Mammals ◽  
Trophic Position ◽  
Sympatric Species ◽  
Isotopic Niche ◽  
Apex Predators ◽  
Skull Morphology ◽  
Ecosystem Based Fisheries Management

AbstractUnderstanding the trophic niches of marine apex predators is necessary to understand interactions between species and to achieve sustainable, ecosystem-based fisheries management. Here, we review the stable carbon and nitrogen isotope ratios for biting marine mammals inhabiting the Atlantic Ocean to test the hypothesis that the relative position of each species within the isospace is rather invariant and that common and predictable patterns of resource partitioning exists because of constrains imposed by body size and skull morphology. Furthermore, we analyze in detail two species-rich communities to test the hypotheses that marine mammals are gape limited and that trophic position increases with gape size. The isotopic niches of species were highly consistent across regions and the topology of the community within the isospace was well conserved across the Atlantic Ocean. Furthermore, pinnipeds exhibited a much lower diversity of isotopic niches than odontocetes. Results also revealed body size as a poor predictor of the isotopic niche, a modest role of skull morphology in determining it, no evidence of gape limitation and little overlap in the isotopic niche of sympatric species. The overall evidence suggests limited trophic flexibility for most species and low ecological redundancy, which should be considered for ecosystem-based fisheries management.

Forest Ecosystems of a Lower Gulf Coastal Plain Landscape: Multifactor Classification and Analysis

2001 ◽  
Vol 128 (1) ◽  
pp. 47 ◽  
Author(s):  
P. Charles Goebel ◽  
Brian J. Palik ◽  
L. Katherine Kirkman ◽  
Mark B. Drew ◽  
Larry West ◽  
...  
Keyword(s):  
Coastal Plain ◽  
Forest Ecosystems ◽  
Gulf Coastal Plain

scholarly journals Estimating maximum bite performance in Tyrannosaurus rex using multi-body dynamics

2012 ◽  
Vol 8 (4) ◽  
pp. 660-664 ◽  
Author(s):  
K. T. Bates ◽  
P. L. Falkingham
Keyword(s):  
Body Size ◽  
Feeding Behaviour ◽  
Ontogenetic Change ◽  
Positive Allometry ◽  
Musculoskeletal Models ◽  
Terrestrial Animal ◽  
Body Dynamics ◽  
Mode Of Life ◽  
Scaling Analyses ◽  
Multi Body

Bite mechanics and feeding behaviour in Tyrannosaurus rex are controversial. Some contend that a modest bite mechanically limited T. rex to scavenging, while others argue that high bite forces facilitated a predatory mode of life. We use dynamic musculoskeletal models to simulate maximal biting in T. rex . Models predict that adult T. rex generated sustained bite forces of 35 000–57 000 N at a single posterior tooth, by far the highest bite forces estimated for any terrestrial animal. Scaling analyses suggest that adult T. rex had a strong bite for its body size, and that bite performance increased allometrically during ontogeny. Positive allometry in bite performance during growth may have facilitated an ontogenetic change in feeding behaviour in T. rex , associated with an expansion of prey range in adults to include the largest contemporaneous animals.

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