宽网叶肢介属重要分类特征的发现

Discovery of important taxonomic features in fossil clam shrimp genus Loxomegaglypta(Crustacea: Spinicaudata)

通过扫描电镜重新研究了产自俄罗斯维特奴河流域下三叠统维特奴宽网叶肢介(Loxomegaglypta wetlugiana Novojilov, 1958)的正模标本。扫描电镜成像揭示了光学照相无法分辨的重要分类学新特征,其中包括:生长带饰有圆形、角状或椭圆形小筛坑状装饰(直径15–25μm),筛坑被不同形状的隆起包围。均匀分布的针孔(直径4–6μm)不但出现在筛坑里,而且布满了筛坑周围的隆起。这种装饰与该属建立时描述的多角状大网格装饰区别较大。在此基础上,本研究修订了宽网叶肢介属生长带的装饰特征。

Re-examination of the holotype specimen of the clam shrimp type species Loxomegaglypta wetlugiana Novojilov, 1958 using a scanning electron microscope(SEM) has revealed details of carapace features with important taxonomic value, which have never been described hitherto. The new features include: growth bands in the middle and ventral part of the carapace are ornamented with circular, angular or elliptical sieve-like fine pits(15 to 25 μm in diameter), which are surrounded by variously shaped, wide swellings. Puncta(4 to 6 μm in diameter) occur not only in the pits, but also on the surrounding swellings. This ornamentation pattern is different from the originally described angular reticulation, and thus the diagnosis of Loxomegaglypta is emended.