山东莱阳隐翅虫科化石一新属二新种(鞘翅目)

A NEW GENUS AND TWO NEW SPECIES OF FOSSIL STAPHYLINIDS (COLEOPTERA) FROM LAIYANG, SHANDONG PROVINCE, CHINA

鞘翅目隐翅虫科是现存的一个种类繁多的大科。但是,中生代的这个类群发现较少,主要分布于我国辽宁的中侏罗世(林启彬,1976)和山东的晚侏罗世(张俊峰,1988)以及前苏联的卡拉套(Kaparay)的晚侏罗世(,1968)和外贝加尔()的早一中侏罗世(,1985)。 本文所描述的我国山东莱阳晚侏罗世的隐翅虫科化石2属2种,其中有1新属2新种。标本采自山东省莱阳市南李格庄村莱阳组的薄层页岩中。所有标本现保存于山东省博物馆。

This paper deals with two genera and two species of the family Staphylinidae from the Late Jurassic of Laiyang Formation in Laiyang City, Shandong Province, China, of which one genus and two species are new to science. AH the specimens described here were collected from the Nanligezhuang Village in Laiyang City, and are kept in the Shandong Provincial Museum.1. Mesostaphylinus fraternus, sp. nov. (Figs. 1, 2)A single specimen, brown in color, No. L84139 (holotype).Body large in size, slender and long. Head subquadrate but slightly longer than wide, with anterior margin arched. Eyes large, circular, lying laterally at median of head. Mandibles small, obviously curved, and sharp apically, at least armed with a single tooth at inner margin. Antennae lost. Maxillary palpi ill-preserved, with the last segment seemingly long and cylindrical. Pronotum longer than head, and 1.5 times as long as wide, with posterior margin distinctly narrower than anterior, anterior angles prominent, posterior angles rounded. Elytra knife-shaped, narrow, and rounded terminally, 3.6 times as long as wide. Prothorax small. Mesothorax and metathorax massive, quadrate, with their boundary indistinguishable. Fore legs with coxae stout, conical, femora clavate, tibiae somewhat shorter and narrower than femora, tarsi unpreserved. Middle legs with femora clavate, noticeably stouter and slightly longer than tibiae, first four tarsal segments preserved, the first nearly as long as the second, and distinctly longer than the third and fourth. Hind legs sparsely covered with long hairs, femora oblong, almost as wide as, and half as long as tibiae, tarsi ill-preserved, the first seemingly elongate. Abdomen seven-segmented, cylindrical, the basal segments subequal in length, terminal part of the sixth and whole of the seventh rather light in color, and clothed with long hairs, the seventh obviously narrower than remainder, about twice as long as the sixth. Apex abdominis armed with a pair of large styli, triangular, about half as long as the seventh.Body 10.2mm long, 1.2mm wide. Comparison: The present new species is closely similar to Mesostaphylinus laiyangensis Zhang, but differs from the latter in shorter head, larger eyes, toothed inner margins of mandibles, narrower knife-shaped elytra, elongate posterior tibiae and the seventh abdominal segment, as well as smaller body.Hesterniasca gen. nov.Type species: Hesterniasca obesa sp. nov.Diagnosis: Of small and massive staphylinids. Head small, transverse, and triangular. Mandibles robust. Eyes large, lying laterally at median of head. Pronotum rather large, transverse, subquadrate, with anterior and posterior angles rounded. Scutellum indistinguishable. Elytra short and wide, rectangular, with basal edge straight and oblique, posterior and lateral margins straight, posterior angles prominent. Abdomen stout and short, seven-segmented. Apex abdominis with styli large, triangular.Comparison: This new genus resembles Abscondus Tichomirova, an extinct genus from Late Jurassic of Karatau, Russia, but separated from the latter in having larger eyes, subquadrate pronotum with the posterior angles rather rounded, indistinguishable scutellum, distinctly short elytra and smaller body.2. Hesterniasca obesa, sp. nov. (Figs. 3,4)A single specimen, light yellowish-brown, but most abdominal segments brown in color, No. L84140 (holotype).Head obtusely triangular, with posterior and lateral margins curved, narrowed anteriorly, 1.3 times as wide as long. Eyes circular, lying laterally at median but a little near anterior of head. Mandibles triangular, robust, short, straight and sharp apically, inner margin without tooth. Antennae ill-preserved. Pronotum 1.7 times as wide as long, and 1.8 times as wide as head, with lateral margins obviously curved, and posterior margin seemingly straight. Elytra almost as wide as, and slightly longer than pronotum, 1.2 times as long as wide. Abdomen 1.5 times as long as wide, a bit narrower than elytra, with the first abdominal segment light yellowish-brown but from the second to the seventh br