. Bulletin of the British Museum (Natural History), Geology. . Fig. 25 Propterus elongatus Wagner. Lateral views of right jaw articulation, as preserved in A, and B, The dermosphenotic is again typical of the family; it forms a short, perforate tube, with a flared dorsal end, which hes against the lateral surface of the sphenotic. Its anterior wall is not prolonged dorsaliy (). (iv) Hyopalatine bones. None of the specimens displays the palate in its entirety. The oral border of the palate rises much more steeply from the jaw articulation than it does in Macro
. Bulletin of the British Museum (Natural History), Geology. . Fig. 25 Propterus elongatus Wagner. Lateral views of right jaw articulation, as preserved in A, and B, The dermosphenotic is again typical of the family; it forms a short, perforate tube, with a flared dorsal end, which hes against the lateral surface of the sphenotic. Its anterior wall is not prolonged dorsaliy (). (iv) Hyopalatine bones. None of the specimens displays the palate in its entirety. The oral border of the palate rises much more steeply from the jaw articulation than it does in Macrosemius. A few tall ectopterygoid teeth are visible in (Fig. 26). The metapterygoid is much as it is in the type genus; this bone contacts the quadrate only in the larger specimens. The hyomandi- bular is not fully exposed in the specimens, although in one of them (37099) the lateral flange may be seen. The quadrate is exposed in Its long dorsoposterior edge is slightly convex (Fig. 25A). The quadratojugal is slender, extending for about twice the length of the quadrate against which it lies. The shaft of the bone is slightly expanded laterally midway along its length; it rests as usual upon the upper surface of the ventral arm of the preopercular. Distally the shaft expands and abuts against the lateral surface of the quadrate condyle; it is not clear from this specimen whether fusion occurs between the two bones in this region as it does in Macrosemius. In another (), however, the preopercular and quadratojugal have together been twisted through about 90 degrees, away from the quadrate. The expanded head of the quadratojugal has pulled away quite cleanly from the quadrate and the two bones evidently were not fused (Fig. 25B). This specimen also shows clearly two notches on the lateral surface of the quadratojugal head. In specimen (Fig. 25A) there lies a short stout bone, about four times as long as broad, in the space between the
Size: 1273px × 1963px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbritishmuseumnaturalhistory, bookcentury1900, bookcoll
