. Bulletin of the British Museum (Natural History) Zoology. 80 GORDON J. HOWES. Fig. 2 Macruronus magellanicus, neurocranium in (left) dorsal and (right) ventral views. BMNH : 352-7 (skeleton). ANATOMY OF MACRURONUS AND COMPARISON WITH MERLUCCIUS External morphology (Fig. 1) Macruronus: Body elongate, strongly compressed with tapered tail. Two dorsal fins separated by slight gap; first short-based, the second confluent with caudal fin. Pectoral fins situated high, level with centre of eye; pelvic origin below or somewhat posterior to pectoral origin. Anal fin extends along posterior h
. Bulletin of the British Museum (Natural History) Zoology. 80 GORDON J. HOWES. Fig. 2 Macruronus magellanicus, neurocranium in (left) dorsal and (right) ventral views. BMNH : 352-7 (skeleton). ANATOMY OF MACRURONUS AND COMPARISON WITH MERLUCCIUS External morphology (Fig. 1) Macruronus: Body elongate, strongly compressed with tapered tail. Two dorsal fins separated by slight gap; first short-based, the second confluent with caudal fin. Pectoral fins situated high, level with centre of eye; pelvic origin below or somewhat posterior to pectoral origin. Anal fin extends along posterior half of body and either confluent with, or separated by indentation from, caudal fin rays. Upper caudal rays often extended. Head relatively short ( TL), jaws oblique, snout short. Opercular border not attenuated and closely attached to body wall. Scales thin and deciduous. Blue coloration. Merluccius: Body moderately compressed with typical sym- metrical gadoid tail. Two dorsal fins, the second with posterior rays extended, not confluent with caudal fin. Pectoral fins low on body, level with lower border of eye. Pelvic origin anterior to pectoral. Anal fin with posterior rays extended and not confluent with caudal fin. Head long ( SL), jaws straight or slightly oblique, lower jaw projecting, snout long. Operculum with attenuated, un- restricted, posterior border. Scales thin and deciduous, ellipsoidal. Silver coloration. Cranium (Figs 2-9) Cranial shape: Macruronus; characterized by cranial depth, relatively short otic and occipital regions and anteriorly tapered roof. Merluccius; cranium depressed, particularly where frontals meet ethmoid region; otic and occipital regions elongate, cranial roof nearly oblong. Detailed differences are: 1. Ethmoid region: Macruronus (Figs 2 & 3). Dorsal ethmoid surface (rostro- dermosupraethmoid) narrow and cruciform, sloping ventrally at 45° with ethmoid bloc (mesethmoid) separated from vomer by shallow cartilage. Lat
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