. Bulletin. Natural history; Natuurlijke historie. EARLY JURASSIC SEMIONOTID FISHES 81 Semionotus profundus, new species Figs. 27, 29, 33, 44; Tables 30, 32 Diagnosis. S. profundus is the most deep-bodied species of the S. tenuiceps group. In lateral view, the large dorsal hump posterior to the head and the prominent robust dorsal ridge scales distinguish it from S. saginatus (compare Figs. 33 and 34). Holotype. YPM 8944 (P4-2071); complete fish, part and counterpart, negatively prepared (Fig. 44) Paratypes. YPM 8913, 8920, 8933, 8934, 8935, 8937, 8938, 8939, 8940, 8941, 8943, 8978 Type locali
. Bulletin. Natural history; Natuurlijke historie. EARLY JURASSIC SEMIONOTID FISHES 81 Semionotus profundus, new species Figs. 27, 29, 33, 44; Tables 30, 32 Diagnosis. S. profundus is the most deep-bodied species of the S. tenuiceps group. In lateral view, the large dorsal hump posterior to the head and the prominent robust dorsal ridge scales distinguish it from S. saginatus (compare Figs. 33 and 34). Holotype. YPM 8944 (P4-2071); complete fish, part and counterpart, negatively prepared (Fig. 44) Paratypes. YPM 8913, 8920, 8933, 8934, 8935, 8937, 8938, 8939, 8940, 8941, 8943, 8978 Type locality. Yale excavation in cycle P4, Pompton, New Jersey Formation. Towaco Formation, Newark Basin Age. Hettangian, Early Jurassic Etymology. From profundus, meaning deep, for the gibbose form of this species Description. S. profundus is very deep bodied, with a pronounced dorsal hump (Figs. 27, 44B). The forehead slopes more steeply than in all others in the S. tenuiceps group, at about 50° from horizontal, so that the curvature is almost continuous with the anterior descending slope of the dorsal hump. Head depth relative to standard length is greater than in all other species in this group except S. saginatus. Maximum depth of the caudal peduncle is also deeper than in all other species, and its outline is almost straight from the dorsal and anal fins to the minimum point of the caudal peduncle, rather than a gently concave curve as in other species. All of these features are most clearly seen in Figures 27 and 29E. Morphometric data are summarized in Table 30. Commensurate with its deeper body, this species has more horizontal scale rows than other species in the S. tenuiceps group except for S. saginatus. There are 11 between the lateral line and the dorsal fin and 10-11 between the lateral line and the anal fin, whereas others in the S. tenuiceps group have 8-9 scales between the lateral line and either fin. Flank scales are largest anteriorly, near. Fig. 33. Dorsal ridge sc
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