. Bulletin of the British Museum (Natural History) Zoology. ANATOMY, PHYLOGENY AND TAXONOMY OF THE GADOID FISH GENUS MACRURONUS 93 ans ns1. Fig. 21 Macruronus magellanicus, vertebral column and dorsal fin supports in lateral view. Drawn from dissection of BMNH : 342- 351, supplemented by radiographs. difference of ca 20. There are nearly three times as many second dorsal fin rays and twice the number of anal rays in Macruronus than Merluccius. Caudal fin skeleton (Fig. 23) In Macruronus eight elements bear caudal fin rays viz, rays having a simple, rounded articulatory head as distinc
. Bulletin of the British Museum (Natural History) Zoology. ANATOMY, PHYLOGENY AND TAXONOMY OF THE GADOID FISH GENUS MACRURONUS 93 ans ns1. Fig. 21 Macruronus magellanicus, vertebral column and dorsal fin supports in lateral view. Drawn from dissection of BMNH : 342- 351, supplemented by radiographs. difference of ca 20. There are nearly three times as many second dorsal fin rays and twice the number of anal rays in Macruronus than Merluccius. Caudal fin skeleton (Fig. 23) In Macruronus eight elements bear caudal fin rays viz, rays having a simple, rounded articulatory head as distinct from anvil or hammer shaped heads of dorsal and anal rays. Three vertebrae (terminal; two preural) are involved directly or indirectly with the caudal rays. Last centrum posteriorly compressed and upturned, having the appearance of a hypural plate to which attach four fin rays. Terminal centrum is assumed to be second ural centrum plus fused 3rd-5th hypurals, and possibly a uroneural. The penultimate vertebrae (assumed to be 1st preural plus 1st ural) is associated with four, posteriorly directed rod-like elements none of which is fused to the centrum. The two ventral elements have cartilaginous proximal and distal tips and each support fin rays. These appear to be the parhypural (anterior element) and fused 1st and 2nd hypurals (posterior element). Both bones articulate with deeply concave ventral surface of the centrum and lie adnate to one another and to the vertebral surface. The two dorsal elements have expanded proximal surfaces which interlock with one another and articulate with the dorsal surface of the centrum. The posterior of these two elements has broad lateral flanges; each element bears a caudal ray and are identified as epurals. The 2nd preural vertebra bears distinct neural and haemal spines, each of which appears to incorporate a radial. The dorsal 'radial' lies adnate to the posterior surface of the neural spine leaving a small space between its proximal ti
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