A revision of the fossil genus Diplomystus : with comments on the interrelationships of clupeomorph fishes. American Museum novitates ; no. 2728

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New York, N.Y. : American Museum of Natural History
Several primitive clupeomorphs are described, and a hypothesis of clupeomorph interrelationships is proposed. The genus Diplomystus is revised and the type species for the genus, rD. dentatus Cope, 1877, is redescribed. Diplomystus dentatus is closely related to D. birdi Woodward, 1895, and D. dubertreti Signeux, 1951, and all three species form the sister group to sEllimmichthys longicostatus (Cope, 1886). Because the dorsal scutes of E. longicostatus lack the pectinate posterior border diagnostic of Diplomystus, Jordan's (1910 and 1919 (in Jordan and Gilbert, 1919)) removal of this species from Diplomystus is considered valid. Both tDiplomystus and Ellimmichthys are placed in lEllimmichthyidae, new family (Diplomystidae is preoccupied by a family of South American catfishes). The cEllimmichthyidae, new family, is the sister group to the Clupeiformes. Armigatus, new genus, is proposed for uClupea brevissimus Blainville, 1818. The relationship of Armigatus brevissimus, new genus, to other clupeomorphs is not clear, and it forms an unresolved trichotomy with cellimmichthyids and clupeiforms. Many other species erroneously assigned to the genus Diplomystus are removed to make the genus monophyletic and thus useful in systematic and comparative anatomical studies. The comparative morphology of clupeomorph dorsal scutes is discussed. It is found that 'double armor' in clupeiforms is not restricted to a small specialized group, but rather is a widespread character, occurring in clupeids, engraulids, "ellimmichthyids, and Armigatus. Detailed morphological study of the dorsal scute in clupeomorphs shows a complex of several characters. some of which can be used to define monophyletic groups within the Clupeomorpha"--P. [1].
34 p. : ill. ; 26 cm.
Includes bibliographical references (p. 30-34).