. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Fig. 14. H. tucki. Stereophotograph of right carpal region, dorsal view. Scale == 5 cm. plete carpi exist; however, the complete carpus of Camptosaurus dispar (Gilmore 1909) does not contain an os centrale, only an os intermedium. An os centrale does exist in the carpus of the alligator (but along with an os intermedium) so it would not be unusual to find its retention in an early ornithischian archosaur. A number of possibilities exist with respect to the fate of the os intermedium in Heterodontosau
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Fig. 14. H. tucki. Stereophotograph of right carpal region, dorsal view. Scale == 5 cm. plete carpi exist; however, the complete carpus of Camptosaurus dispar (Gilmore 1909) does not contain an os centrale, only an os intermedium. An os centrale does exist in the carpus of the alligator (but along with an os intermedium) so it would not be unusual to find its retention in an early ornithischian archosaur. A number of possibilities exist with respect to the fate of the os intermedium in Heterodontosaurus, but it is impossible to choose among them: (i) the os inter- medium has been lost in the Heterodontosaurus lineage; (ii) the os intermedium has fused with the ulnare, as in Stegosaurus (Gilmore 1914); (iii) the os inter- medium has fused with the radiale; (iv) the os intermedium has become dis- placed inferiorly by the growth of the radiale and/or ulnare, to occupy the position of an os centrale. The phylogenetic history of the carpus in Heterodonto- saurus thus remains unknown for the present. The radiale is a flat, plate-like bone, articulating with the entire distal surface of the radius; it is transversely elongated to match the distal, expanded shaft of the radius. The ulnare, proximodistally thicker than the radiale, contacts the radiale on the inferior half of its medial margin while the superior half of the medial margin is in contact with the distal end of the radial shaft. As noted above, the superior surface of the ulnare is transversely concave to accept the rounded end of the ulnar shaft; distally, the ulnare has a flat articular surface. The lateral surface of the ulnare has two facets, the inferolateral for distal carpal 5, the superolateral for the pisiform. The pisiform is a cuboidal element in contact with both ulnare and ulna. The intervening bony element in the carpus is biplanar, in contact proximally only with the ulnare, but with distal carpals 2, 3
Size: 1522px × 1643px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
