Figure 8

Skeletal and fibrous abnormalities in individuals of Dugongs and hyracoids with an aberrant number of cervical vertebrae. A) Dendrohyrax arboreus (RMCA 22057) skeleton with full ribs on the seventh vertebra (arrows) and a sixth cervical vertebra with on the right the identity of a normal seventh vertebra and on the left of a normal sixth vertebra (with anterior tuberculum, arrowhead). B) Dugong dugon (RBINC 1.183d) with articulation facets for rudimentary ribs on the seventh cervical vertebra (arrows). Note the irregular shape of the cervical vertebral bodies, in particular of the sixth one (arrowhead). C) Dugong dugon (RMNH.MAM.27523) with a small rudimentary rib on the first caudal vertebra that is fused to the last thoracic rib (arrow). Note that the transverse process of the second caudal vertebra is fused to the rudimentary rib. D) Forefoot of a Dendrohyrax arboreus (RMCA 22057) showing four instead of five digits. Same specimen as in A) with full cervical ribs. E) Abnormally shaped scapulae of a Procavia capensis (RMCA 20098) with rudimentary cervical ribs. F) Abnormal ossification of tendons in the limb of a Dugong dugon (RBINC 1.183d) with rudimentary cervical ribs (same specimen as B). G) Dugong dugon (RMNH.MAM.27523)with fused second and third vertebrae (arrow) with a unilateral rudimentary rib (not shown).