A review of mesozoic acanthopterygian fishes, with special reference to those of the English chalk

Abstract

Acid preparation of fishes from the English Chalk allows very detailed descriptions to be prepared. The acanthopterygians of the English Chalk are redescribed, and members of all the genera known by more than one specimen are treated at length. The English Chalk genera of Ctenothrissiformes, a group confined to the Cenomanian and Lower Turonian, are also described in detail, since this group is often cited as possibly ancestral to the acanthopterygians. The acanthopterygians and Ctenothrissiformes of all other Mesozoic deposits are more briefly described. The main systematic conclusions are as follows. A new order Ctenothrissiformes is made, to replace the Bathyclupeiformes, since Bathyclupea is a percoid. Within the Ctenothrissiformes, a new family Aulolepidae is made to contain Aulolepis and Pateroperca (the latter was formerly thought to be a percoid). The order Berycifbrmes is divided into three new sub-orders, Polymixioidei, Dinopterygoidei and Berycoidei. The Polymixioidei contains two families, the Polymixiidae, ranging from the Cenomanian to the present, and a new monotypic family Sphenocephalidae, confined to the Upper Senonian. The family Berycopsidae is rejected, and Berycopsis is placed in the Polymixiidae. Platycormus is shown to be a synonym of Berycopsis. The Dinopterygoidei contains the Upper Senonian Dinopterygidae and three new monotypic families, the Aipichthyidae, Pharmacichthyidae and Pycnosteroididae, all of which are confined to the Cenomanian. The Berycoidei contains eleven families, all with living representatives, of which only the Trachichthyidae and Holocentridae are present in the Mesozoic. A new genus of Trachichthyidae, Tubantia, from the Upper Senonian of Westphalia, is made. The genus Hoplopteryx, previously placed in the Berycidae, is shown to be a trachichthyid, and two new species of H. macranthus and H. gephyrognathus, both from the English Chalk, are described. Among the Perciformes, a new genus of Serranidae, Proseanu, is made for a species from the Danian of Sweden, and Bathysoma, from the same horizon and locality, is shown to be a member of the Menidae. The genus previously thought to be a percoid, is shown to be a member of the Tselfatiidae (Beloniformes). It is suggested that Protiacnhus, previously placed in the perciform sub-order Balistoidei, may be related to the Aulostomiformes.