Macroscopic Recognition of Nontraumatic Osseous Pathology in the Postcranial Skeletons of Crocodilians and Lizards
Identification of postcranial reptile pathology unrelated to trauma on the basis of macroscopic (visual) examination is feasible and effective, as previously documented in mammals, birds, and dinosaurs. Such bone disease is rare in most wild-caught lizards, with the exception of Varanids, and is also more common in crocodilians. This provides a basis for evaluation of the fossil record, suggesting that the most productive epidemiologic analyses would be concentrated in the families, Crocodylidae and Varanidae. A specific form of inflammatory arthritis and vertebral pathology, spondyloarthropathy, is clearly established as the major non-traumatic osseous pathology in lizards (although quite rare in all but varanids) and crocodilians. Calcium pyrophosphate deposition disease seems to represent a secondary phenomenon, apparently limited in distribution to individuals with spondyloarthropathy. Only 9% of individual reptiles with osseous pathology examined lacked a clear diagnosis substantiated by validated observations in human and other animals.Abstract
Ventral view of vertebrae. (A) Syndesmophytes diffusely bridging vertebral bodies of AMNH 57765 Varanus salvator in a smooth flowing pattern effacing caudad/cephalad margins of individual vertebrae. (B) Syndesmophytes diffusely bridging vertebral bodies of AMNH 127116 Varanus niloticus (bottom image), characteristic of spondyloarthropathy. Fusion of the ribs to the vertebrae (costovertebral joint fusion) is also noted, characteristic of spondyloarthropathy.
(A) Dorsal view (upper image) of distal radius of NMNH 228163 Varanus komodoensis. Marginal erosions (holes and grooves of spondyloarthropathy) are prominent at the left border. (B) Proximal view (lower image) of metapodial of ROM 7565 Varanus komodoensis. Subchondral erosions (grooves and holes) are prominent at the lower portion of the image, characteristic of spondyloarthropathy.
(A) Anterior view of posttraumatically fused forelimb of AMNH 97300 Caiman yacare. Outgrowth of bone with thick distal portion, characteristic of osteochondroma. (B) Posterior-lateral view (lower image) of tibia of AMNH 79606 Varanus komodoensis. Periosteal elevation, characteristic of hematoma.
Posterior view of vertebrae of ROM 42980 Dipsosaurus dorsalis. Serpentine pattern with nonfused zygapophyseal joints, characteristic of congenital anomaly.
(A) Posterior view of metatarsal of NMNH 63810 Varanus salvator. Hole with smooth internal margins, characteristic of gout. (B) Ventral view of AMNH 118713 Varanus benegalensis. Multiple calcium deposits, characteristic of calcium pyrophosphate deposition disease.
