Reconstruction of body cavity volume in terrestrial tetrapods.
Although it is generally assumed that herbivores have more voluminous body cavities due to larger digestive tracts required for the digestion of plant fiber, this concept has not been addressed quantitatively. We estimated the volume of the torso in 126 terrestrial tetrapods (synapsids including basal synapsids and mammals, and diapsids including birds, non-avian dinosaurs and reptiles) classified as either herbivore or carnivore in digital models of mounted skeletons, using the convex hull method. The difference in relative torso volume between diet types was significant in mammals, where relative torso volumes of herbivores were about twice as large as that of carnivores, supporting the general hypothesis. However, this effect was not evident in diapsids. This may either reflect the difficulty to reliably reconstruct mounted skeletons in non-avian dinosaurs, or a fundamental difference in the bauplan of different groups of tetrapods, for example due to differences in respiratory anatomy. Evidently, the condition in mammals should not be automatically assumed in other, including more basal, tetrapod lineages. In both synapsids and diapsids, large animals showed a high degree of divergence with respect to the proportion of their convex hull directly supported by bone, with animals like elephants or Triceratops having a low proportion, and animals such as rhinoceros having a high proportion of bony support. The relevance of this difference remains to be further investigated.
Clinic for Zoo Animals, Exotic Pets and Wildlife, University of Zurich, Zurich, Switzerland.
Marcus
M
Clauss
Computer Vision and Remote Sensing, Technical University Berlin, Berlin, Germany.
Irina
I
Nurutdinova
Research Centre in Evolutionary Anthropology and Palaeoecology, Liverpool John Moores University, Liverpool, UK.
Carlo
C
Meloro
CharitéCrossOver - Institute of Physiology, Berlin, Germany.
Hanns-Christian
HC
Gunga
Computer Vision and Remote Sensing, Technical University Berlin, Berlin, Germany.
Duofang
D
Jiang
Computer Vision and Remote Sensing, Technical University Berlin, Berlin, Germany.
Johannes
J
Koller
Senckenberg Research Institute and Natural History Museum, Frankfurt (Main), Germany.
Bernd
B
Herkner
Steinmann Institute of Palaeontology, University of Bonn, Bonn, Germany.
P Martin
PM
Sander
Computer Vision and Remote Sensing, Technical University Berlin, Berlin, Germany.
Olaf
O
Hellwich
D000818:Animals; D005075:Biological Evolution; D049628:Body Size; D002335:Carnivora / Q000033:anatomy & histology*; D025061:Dinosaurs; D041981:Gastrointestinal Tract / Q000033:anatomy & histology*; D060434:Herbivory; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008322:Mammals
anatomy; carnivory; digestive tract; herbivory; photogrammetry; ribcage