【摘要】 文中描述的2个新属(Bohainia, Parabohainia)和23个新种均属于华北介亚科(Huabeininae)。这些新材料为研究渤海盆地早第三纪这一特殊介形类动物群的分区、生态环境等提供了新的内容。更多还原

【Abstract】 The ostracods described and illustrated in this paper were collected from the Palaeogene of the Bohai Gulf, with two new genera and 23 new species referred to the subfamily Huabeininae. According to sedimentary characteristics and fossil assemblages, the Palaeogene of the Bohai Gulf was divided into the Kongdian, Dongyang and Shahejie Formations. Up to now, no fossil ostracods have been found from the lowest Kongdian Formation, but they are quite abundant in the latter two formations. Here the stratigraphical subdivision of the latter two formations together with the distribution of ostracod assemblages are given in ascending order as follows:Eocene—Oligocene Shahejie Formationa. Fourth Member of Shahejie Formation: Austrocypris levis-Eucypris albata assemblage;b. Third Member of Shahejie Formation: Huabeinia chinensis assemblage;c. Second Member of Shahejie Formation: Camarocypris elliptica assemblage; andd. First Member of Shahejie Formation: Phacocypris huiminensis-Limnocy-there armata assemblage.Oligocene Dongying Formationa. Lower Member of Dongying Formation. Xiyingia luminosa assemblage in the lower part and Chinocythere subtriangulata-Dongyingia gracilinflexicostata assemblage in the upper part. b. Upper Member of Dongying Formation: with no ostracods found.Description of New Genera and SpeciesFamily Cyprididae Baird, 1845Subfamily Huabeininae Bojie, 1978Genus Bohainia gen. nov.Etymology Bohai Gulf, the locality of the fossil.Type species Bohainia sinensis gen. et sp. nov.Diagnosis Shell large, with thickened valves subrhombic or irregularly reniform in lateral view, higher anteriorly. Anterior end of carapace broadly rounded; posterior end sharply rounded; ventral margin convex, with upwardly compressed ends. Left valve larger than right one, overlapping the latter along free margin; valve surface smooth or covered with striations and reticulation. Hinge region concave, forming a sulcus; hinge simple, with dorsal border of the right valve fitting into a shallow groove along dorsal margin of the left valve. Inner lamella moderately developed and wider on the anterior margin. Vestibule relatively wide and compressed. Pore canal zone rather wide; radial pore canals delicate and numerous, with part of them bifurcate; normal pore canals fine, straight and rare. Central muscle scars very clear, belonging to Cyprididae type.Discussion This genus is similar to Limnocypridea Lubimova, 1956 in the shape of its lateral view, in the size of its carapaces which overlap each other, but differs from it in the more broadly rounded anterior end, acute to rounded posterior end, outwardly convex ventral margin, wider pore canal zone and more numerous radial pore canals with binary branches. The new genus is also similar to Bairdia McCoy, 1844 in lateral outline, but differs from the latter in having muscle scars of the Cyprididae type.Stratigraphical range Oligocene.Bohainia sinensis gen. et sp. nov.(P1. Ⅰ, figs. 1—7; text-figs. 1—4)Diagnosis Shell large with thickened valves, subrhombic in lateral outline, with short, neatly straight and backwardly sloped dorsal margin, highest at the anterior two-fifths; cardinal angles bluntly rounded; ventral margin outwardly convex, with upwardly curved ends; anterior end higher and more broadly rounded than the posterior end, usually sharply rounded and extended; antero-dorsal margin long and slightly concave; postero-dorsal margin low-arcuate. Left valve larger than right one, mostly overlapping the latter except for the hinge margin. Surface of valves smooth; lateral outline symmetrically convex and extremities acuminate in dorsal view, forming a fusiform shape, with the greatest width in the middle. Hinge region concave, forming a narrow and shallow sulcus; hinge simple, with the dorsal border of the right valve fitting into a shallow groove of the left valve (P1. Ⅰ, fig. 5; text-fig. 1). Inner lamella moderate in width, with slightly outwardly sinuous inner margin. Vestibule developed. Pore canal zone rather wide, about two-fifths as wide as inner lamella (Text-fig. 2); radial pore更多还原