. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Fig. 6. H. tucki. Stereophotograph of caudal vertebrae 3-12, left lateral view. Note distal portions of ischium and postpubic rod in lower left corner of matrix block. Scale = 5 cm. that would bridge the gap between the two groups can be estimated by com- paring the mid-central heights of the two vertebrae at the ends of the gap. (This measure seems to decrease uniformly from anterior to posterior caudals, while centrum length increases and decreases several times within the caudal series.) The diffe
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Fig. 6. H. tucki. Stereophotograph of caudal vertebrae 3-12, left lateral view. Note distal portions of ischium and postpubic rod in lower left corner of matrix block. Scale = 5 cm. that would bridge the gap between the two groups can be estimated by com- paring the mid-central heights of the two vertebrae at the ends of the gap. (This measure seems to decrease uniformly from anterior to posterior caudals, while centrum length increases and decreases several times within the caudal series.) The difference in height is 1,5 mm; this corresponds to 6 vertebrae in the first group and to 9 in the second. Presumably, then, at least 6 but not more than 9 caudals intervened between the two segments preserved. The caudal centra do not have a consistent pattern of variation in shape or length. In the first seven caudals the anterior central surface is inclined postero- dorsally while the posterior surface is perpendicular to the long axis of the centrum. The remaining centra in the first group are rectangular. Centra 4 to 7 of the last block have a parallelogram outline, the dorsal margin anterior to the ventral; the other centra are rectangular. The length of the centra increases from about 15 mm for sacral 1 to about 18 mm for sacral 11. In the second group, length is approximately constant at 16 mm. Several features are common to the first nine caudal centra. The ventral margin is markedly concave; this is accentuated by the inferiorly projecting articulation with the chevrons. Beyond caudal 9 the area of heamal arch articulation decreases and the inferior border becomes more gently concave. On the lateral surface of the centra a fossa lies below the transverse process; a ridge marks the middle of the ventral margin. The size of the fossa decreases from the first to ninth caudal and disappears at caudal 10. Transverse processes are found on all twelve caudals of the first group a
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
