Marc Verha
Wed, Jan-31-07, 17:16
The paleobiology of the robust australopithecines
(Paranthropus): a test of the durophage model with trace
element analysis. AB Shabel 2007 AAPA abstracts
Most early hominin fossil localities in Africa are associated
with ancient wetlands, however the extent to which early
hominins used wetland habitats and resources is not known. I
have argued previously that the craniodental anatomy of robust
australopithecines (Paranthropus) can be explained as an
adaptation to a diet that included hard-shelled invertebrates
such as freshwater crabs and molluscs. Here I test this
durophage model through an analysis of the trace element
biogeochemistry of more than 35 species of extant African
vertebrates - including aquatic, semi-aquatic, and terrestrial
forms - with a focus on smalland medium-sized carnivorans. I
also include an exhaustive analysis of freshwater crab tissues
(Potamonautidae), the primary food source of three extant
African taxa (Aonyx, Atilax, Varanus niloticus). The ratio of
strontium to barium (Sr:Ba) is found to statistically
distinguish taxa that forage in freshwater (Hydrictis) from
those that forage amphibiously on land and in freshwater
(Aonyx, Atilax, Varanus niloticus) from those that forage
terrestrially (including both carnivores and herbivores).
Sr:Ba increases from freshwater aquatic to semi-aquatic to
terrestrial ecologies, in part as a result of the high levels
of barium in crab tissue, a major wetland food resource.
Coastal populations of Aonyx and Atilax that consume marine
prey have the highest Sr:Ba ratios because of the very low
levels of barium in seawater. These overall biogeochemical
patterns are evident across sub-Saharan Africa. I compare
these results with the published literature on fossil
hominins, including Australopithecus and Paranthropus, and I
conclude that the durophage hypothesis has not been falsified.
(Paranthropus): a test of the durophage model with trace
element analysis. AB Shabel 2007 AAPA abstracts
Most early hominin fossil localities in Africa are associated
with ancient wetlands, however the extent to which early
hominins used wetland habitats and resources is not known. I
have argued previously that the craniodental anatomy of robust
australopithecines (Paranthropus) can be explained as an
adaptation to a diet that included hard-shelled invertebrates
such as freshwater crabs and molluscs. Here I test this
durophage model through an analysis of the trace element
biogeochemistry of more than 35 species of extant African
vertebrates - including aquatic, semi-aquatic, and terrestrial
forms - with a focus on smalland medium-sized carnivorans. I
also include an exhaustive analysis of freshwater crab tissues
(Potamonautidae), the primary food source of three extant
African taxa (Aonyx, Atilax, Varanus niloticus). The ratio of
strontium to barium (Sr:Ba) is found to statistically
distinguish taxa that forage in freshwater (Hydrictis) from
those that forage amphibiously on land and in freshwater
(Aonyx, Atilax, Varanus niloticus) from those that forage
terrestrially (including both carnivores and herbivores).
Sr:Ba increases from freshwater aquatic to semi-aquatic to
terrestrial ecologies, in part as a result of the high levels
of barium in crab tissue, a major wetland food resource.
Coastal populations of Aonyx and Atilax that consume marine
prey have the highest Sr:Ba ratios because of the very low
levels of barium in seawater. These overall biogeochemical
patterns are evident across sub-Saharan Africa. I compare
these results with the published literature on fossil
hominins, including Australopithecus and Paranthropus, and I
conclude that the durophage hypothesis has not been falsified.