江西弋阳梅溪早侏罗世昆虫

SOME EARLY JURASSIC INSECTS FROM MEIXI OF YIYANG COUNTY, JIANGXI

本文描述了产于江西弋阳梅溪门口山组昆虫化石4属、4种,其中1新属、1新种。根据化石可确定含化石地层时代为早侏罗世。这些昆虫化石的发现使中生(虫非)蠊化石组合的分布范围北延至赣东北。

Here described are 4 genera and species of fossil insects from Meixi of the Yiyang Basin in Northeast Jiangxi. The fossil insect-bearing bed lies in the lower part of the Lower Jurassic Menkoushan Formation, which is a coal-bearing sedimentary formation widely exposed in this area. The Lower Jurassic insects have been known from other parts of South China, but not from Jiangxi in the past. The insect fauna studied in the present paper can be referred to the Early Jurassic Mesoblattino Assemblage of South China (Lin, 1986). Description of New Species Family Geinitziidae Handlirsch, 1906 Genus Meixiella gen. nov. Type species Meixiella postiretis gen. et sp. nov. Fore-wing Subcastal area broad, Sc vein long. R vein with 3 branches at apical part, each of which bends forward and ends in the fore margin; Rs separating from R vein at one-third of wing and having 6 branches. MA branching earlier than Rs, with 4 branches; Mp with 2 branches. CuA same as Mp; Cup single, but strong. With dense cross-veins in the basal part of the wing and having 'H' or 'Y'-shaped cross-vein present between CuA, Cup and A1. Comparison The genus Meixiella is closely allied to Nivopteria Lin, 1978, but differs from the latter in its more branches and 'H' or 'Y'-shaped cross-veins present in Rs, M and CuA fields of the fore wing; in some features the new genus is also similar to Shurabia, but differs from the latter in the branches of main veins of the fore wing which occur earlier than those of Shurabia, and with 'H' and 'Y'-shaped cross veins between Rs ana A veins. Meixiella postiretia gen. et sp. nov. (Pl. Ⅰ, fig. 6; text-fig. 4) Complete fore wing is elliptical, with rounded apical margin and out-bending to the costal margin; the hind margin of the fore wing is straight. The length of the fore wing is 18mm, and the width 7mm. Venation Subcosta (Sc) with 14 obligue branches, all of which ending at costal margin of each; subcostal area broad. The stem of radius (R) very long and having 3 branches at the apical portion, bending forward. Radial sector (Rs) separating from R stern in the middle, then striaght to the apical portion, with 6 branches, ending in the costal margin. With cross-veins between Sc-R and R-Rs. The median stem is shorter than the radial stem, anterior media (MA) separting from M stem, running obliquly and forking into two branches at the level of MA first point, which end in the hind margin. Cubltal vein developed. With dense and strong cross-veins between M-Cu and 'H' or 'Y'-shaped cross veins between Cup-A_1 and A_1 and A_2.