Mollusks from the upper Shackleton Limestone (Cambrian Series 2), Central Transantarctic Mountains, East Antarctica

An assemblage of Cambrian Series 2, Stages 3–4 conchiferan mollusks from the Shackleton Limestone, Transantarctic Mountains, East Antarctica is formally described and illustrated. The fauna includes one bivalve, one macromollusk and ten micromollusks, including the first description of the species Xinjispira simplex outside North China. The new fauna shows some similarity to previously described micromollusks from lower Cambrian glacial erratics from the Antarctic Peninsula. The fauna, mainly composed of steinkerns, is relatively low diversity, but the presence of diagnostic taxa, including helcionelloid Mackinnonia rostrata, bivalve Pojetaia runnegari, cambroclavid Cambroclavus absonus and bradoriid Spinospitella coronata as well as the botsfordiid brachiopod Schizopholis yorkensis in the overlying Holyoake Formation correlates the succession to the Dailyatia odyssei Zone (Cambrian Stage 3–4) in South Australia.本文正式描述并图解了采自东南极洲横贯南极山脉沙克尔顿灰岩的寒武纪第二统第3-4阶具壳软体动物（conchiferan mollusks）化石组合。该动物群包含1种双壳类（bivalve）、1种大型软体动物（macromollusk）以及10种微型软体动物（micromollusks），其中涵盖了华北地区以外新脐螺（Xinjispira simplex）的首次正式描述。这一新发现的动物群与此前报道的南极半岛下寒武统冰川漂砾中的微型软体动物存在一定相似性。该动物群主要由内模化石（steinkerns）构成，分异度相对较低，但其中包含的具鉴定意义的类群（diagnostic taxa）——包括海琳娜螺类（helcionelloid）喙状麦肯尼亚螺（Mackinnonia rostrata）、双壳类鲁内加里波杰塔蛤（Pojetaia runnegari）、坎巴棒形类（cambroclavid）异常坎巴棒形虫（Cambroclavus absonus）、布拉迪虫类（bradoriid）冠状刺孢虫（Spinospitella coronata），以及上覆霍利约克组中的博茨福特亚目腕足动物（botsfordiid brachiopod）约克裂面腕足（Schizopholis yorkensis）——将该地层序列与南澳大利亚的奥德赛戴利塔利兹带（Dailyatia odyssei Zone，寒武纪第3-4阶）进行了地层对比。