Numberger-Thuy Lea D, Thuy Ben
Natural History Museum Luxembourg, Department of Palaeontology, 25, rue Münster, 2160 Luxembourg, Luxembourg.
Zootaxa. 2020 Jul 27;4820(1):zootaxa.4820.1.2. doi: 10.11646/zootaxa.4820.1.2.
Identifiable remains of large deep-sea invertebrates are exceedingly rare in the fossil record. Thus, every new discovery adds to a better understanding of ancient deep-sea environments based on direct fossil evidence. Here we describe a collection of dissociated skeletal parts of ophiuroids (brittle stars) from the latest Pliocene to earliest Pleistocene of Sicily, Italy, preserved as microfossils in sediments deposited at shallow bathyal depths. The material belongs to a previously unknown species of ophiacanthid brittle star, Ophiacantha oceani sp. nov. On the basis of morphological comparison of skeletal microstructures, in particular spine articulations and vertebral articular structures of the lateral arm plates, we conclude that the new species shares closest ties with Ophiacantha stellata, a recent species living in the present-day Caribbean at bathyal depths. Since colonization of the deep Mediterranean following the Messinian crisis at the end of the Miocene was only possibly via the Gibraltar Sill, the presence of tropical western Atlantic clades in the Plio-Pleistocene of the Mediterranean suggests a major deep-sea faunal turnover yet to be explored.
在化石记录中，大型深海无脊椎动物的可识别遗骸极为罕见。因此，每一项新发现都有助于基于直接化石证据更好地了解古代深海环境。在此，我们描述了一批来自意大利西西里岛上新世晚期至更新世早期的蛇尾类（蛇尾）骨骼解离部分，它们作为微化石保存在浅海深海深度沉积的沉积物中。这些材料属于一种此前未知的棘蛇尾类蛇尾新物种，即大洋棘蛇尾（Ophiacantha oceani sp. nov.）。基于骨骼微观结构的形态学比较，特别是侧腕板的棘关节和椎体关节结构，我们得出结论，该新物种与星棘蛇尾（Ophiacantha stellata）关系最为密切，星棘蛇尾是一种生活在当今加勒比海深海深度的现存物种。由于中新世末期梅西尼安危机之后，地中海深海的殖民化仅可能通过直布罗陀海峡，地中海上新世 - 更新世出现热带西大西洋类群表明仍有待探索的重大深海动物群更替。
