云南文山大窗鱼(Macrothyraspis)属一新种

A NEW SPECIES OF MACROTHYRASPIS (GALEASPIDA, AGNATHA) FROM WENSHAN, YUNNAN, CHINA

记述了产于云南文山古木早泥盆世坡松冲组华南鱼类大窗鱼一新种——长矛大窗鱼(Macrothyraspis longilanceus sp.nov.)。新种头甲呈头盔形,吻突与角均很发育,中背孔呈后缘前凹的桃形,头甲背面具一对蚕豆形的背窗,纹饰为细小的粒状瘤点,这些特征与属型种——长角大窗鱼(Macrothyraspis longicornis)相似。但新种吻突特别长,约为头甲中长的2 倍,眶孔背位,两个背窗之间脑腔和迷走腔区域相对较宽,两个侧向延伸的角向后倾斜,末端不前翘等,与属型种区别明显,应为该属的一新种。

A new species of galeaspid agnathan, Macrothyraspis longilanceus, is described from the Early Devonian Posongchong Formation （Upper Pragian） at Zhichang village, Gumu Town, Wenshan District, southeastern Yunnan, China. As a typical non-marine deposit, the Posongchong Formation in southeastern Yunnan yields abundant remains of early vascular plants, antiarchs, sarcopterygians and galeaspids, the latter including Kwangnanaspis subtriangularis （Cao, 1979） , Gantarostrataspis gengi, Gumuaspis rostrata （Wang and Wang, 1992）, Macrothyraspis longicornis （Pan, 1992 ）, Wenshanaspis zhichangensis and Sanqiaspis rostrata （Zhao et al. , 2002）.