. Bulletin of the British Museum (Natural History), Geology. . Brr mm Fig. 50 Caturus sp. from the Lower Kimmeridgian of Bavaria, P44900. Left and right serrated appendages, branchiostegais and ventral parts of mandible and cleithrum, as preserved. this specialization indicative of relationship between these two groups; it also occurs in their fossil relatives. Median neural spines also occur in Dapedium, Tetragonolepis and pycnodonts (Patterson 1973)and in the palaeoniscoids Australosomus and Birgeria (Nielsen 1949). The presence of paired neural spines in the Macrosemiidae provides a strong
. Bulletin of the British Museum (Natural History), Geology. . Brr mm Fig. 50 Caturus sp. from the Lower Kimmeridgian of Bavaria, P44900. Left and right serrated appendages, branchiostegais and ventral parts of mandible and cleithrum, as preserved. this specialization indicative of relationship between these two groups; it also occurs in their fossil relatives. Median neural spines also occur in Dapedium, Tetragonolepis and pycnodonts (Patterson 1973)and in the palaeoniscoids Australosomus and Birgeria (Nielsen 1949). The presence of paired neural spines in the Macrosemiidae provides a strong indication that this family belongs neither in the Halecomorphi nor in the Teleostei. (viii) Pectoral girdle and fin. The discovery of a serrated appendage in one specimen of Propterus elongatus is of special interest, since such a bone is known to occur only in Amia (Fig. 49; Wilder 1876 : 259) and Caturus (Fig. 50). That of Amia is discussed by Liem & Woods (1973). Both left and right serrated appendages are preserved in an acid-prepared specimen (BM(NH) P44900) of Caturus Ifurcatus of standard length 130 mm. The right appendage, the better preserved, lies along the ventral arm of the cleithrum. Its surface is traversed by 14 ridges bearing small, three-spined denticles pointing posteriorly; similar denticles occur in vertical rows on the cleithrum. As in Amia, the ridges slope forward dorsoventrally, although in contrast to Amia, the ridges are all of approximately equal length and do not branch. The proximal end of the appendage was presumably embedded in the sternohyoideus musculature, the remainder of the bone pro- jecting freely into the opercular cavity. That the appendage did project, rather than lie embedded in the skin, is indicated by the presence of denticles on the medial surface; these are visible in the specimen at the distal tip of the bone. In addition to the appendage, Amia also possesses a flat plate of bone, also bearing denticulated ridges, embedded in
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