福建早二叠世叶肢介一新属

A NEW CONCHOSTRACAN GENUS FROM LOWER PERMIAN TONGZIYAN FORMATION, FUJIAN

中国古生代的叶肢介知之甚少,南方早二叠世的叶肢介迄今尚无正式文献记载。1974年4月,福建地质一团在该省进行煤田勘探时,曾于钻孔中发现叶肢介化石,标注层位为龙潭组。只因化石数量太少,壳瓣保存不完整,产地又不详尽,因此,一直未作报道。之后,福建196煤田地质勘探队王信,在下二叠统童子岩组也找到了这一类型的叶肢介。1982年11月,

The Early Permian conchostracans described in the paper are reported for the first time in China. A new. genus Phymolimnadiopsis attributed to Subfamily Anomalonematinae has been recognized in the 1st member of the Lower Permian Tongziyan Formation of Fujian Provience. The Tongziyan Formation is divided into three members in descending order as follows: Late Early Permian. 3rd member of Tongziyan Formation Dark grey siltstones, mudstones and qartze-sandstones intercalacted with coal beds, containing fossil plants Gigantonoclea fukienensis, Gigantopteris nicontianaefolia, Schizoneura marchuriensis, Sphenophyllum sino-coreanum; nautiloids Endolobus p., Shouchangoceras sp.; and brachiopods Neoplicatifera huangi, Monticulifera sinensis, Tyloplecta yangtzeensis, Schizodus sp., Lingula sp. 401m 2nd member of Tongziyan Formation Dark grey sandy mudstones, siltstones and sandy limstones, without coal measures, containing fusulinacean Schwagerina sp.; ammonoids Altudoceras sp., Paraceltites sp., and brachiopods Permundaria shizipuensis, Uncisteges crenulata, Haydenella longyangensis, Neochonetes sp. 132m 1st member of Tongziyan Formation Dark grey siltstones, sandy mudstones and coal measures alternating with fine sandstones, containing fossil plants Gigantonoclea fukienensis, Pecopteris anderssonii, Lepidodendronoculus-felis; nautiloids Shangraoceras sp., Shouchangoceras sp.; brachiopods Neoplicatifera huangi, Tenuichonetes tenuilirata, Pygmochonetes jingxianensis; and conchostracans Phymolimnadiopsis spinosus, P. fujianensis 247m The Tongziyan Formation contains abundant elements of the Cathaysia flora, especially gigantopterids which represent a type of the woody limbers of the tropical rain forest. The conchostracan new genus preserved in dark grey sandy mudstone was found to be associated with the bivalve Paleoneilo sp., the brachiopod Lingula and some eumalacostracans. It might be an element which adapted itself to the tropical climate and lived in a seashore and marsh environment. Description of new genus and species Phymolimnadiopsis gen. nov. Type species: phymolimnadiopsis spinosus gen. et sp. nov. Diagnosis: Carapace valve moderate in siz e, suborbicular or elliptical in outline; growth lines recurved near dorsal margin, bearing a row of longer spines of low relief on the middle part; nodes formed at the base of spines. Remarks: The new genus is very similar to Anomalonema (Defretin-Lefrance, 1970) in the shape of the carapace valve and the spines of growth lines, but it differs from the latter in the much longer radial spines originating from the middte part of the growth lines, instead of along the lower margin. Sinoestheria and Ganestheria widely spread in the Cretaceous of S. China also have a row of nodes on the growth lines, but the nodes of both genera are larger than those of the new genus and not extending low forwards. Paleolimnadiopsis and Phymolimnadiopsis are very similar in the shape of carapace valve, but the former has no any spines on the growth lines. Distribution: Early Permian, China. Phymolimnadiopsis spinosus gen. et sp. nov. (P1. Ⅰ, figs. 1—5; text-fig. 2) Carapace valve 8—12mm in length, 5.3—6.8 mm in height, elliptical in outline. Dorsal margin arched and serrated. Umbo small, located on external margin. Anterior height smaller than posterior height. Growth lines stout, recurved near the dorsal margin. Postero-dorsal angle projecting up forwards like an apophysis. Each growth line with a row of radial spines, about 0.5mm in length. Nodes formed at the base of spines. Locality and horizon: Cuifenggou, Caoxi village and Yanshan village, Longyan City, Fu jian; Lower Permian Tongziyan Formation. Phymolimnadiopsis fujianensis gen. et sp. nov. (P1. Ⅰ, figs. 6—10) The new species is associated with P. spinosus. It differs from the latter in the carapace valve suborbicular in outline. Locality and horizon: Same as the preceding.