This study reports diverse spiriferellid brachiopods from the Permian rocks of Svalbard and adjacent areas (Arctic Canada and Subpolar Urals of Russia) located at the northern margin of Pangaea. In total, 11 brachiopod species in four genera are recognized and described in detail, including two new species (Spiriferella protodraschei and Arcullina? enokiani). According to our taxonomic investigation, morphological characteristics of the ventral sulcus and dorsal fold are relatively stable within each species, in spite of considerable intraspecific variations in shell outline and macro-ornamentation. In addition, both the arrangement of pustules, as a shell surface micro-ornamentation, and the development of delthyrial coverings are shown to be significant features for inferring phylogenetic relationships and for defining species. The best-known but still questionable taxon, Spiriferella keilhavii, is here identified as an endemic species restricted to Bjørnøya and, possibly, to central East Greenland; it is phylogenetically closest to S. loveni. Following the taxonomic revision, the stratigraphical ranges of the spiriferellids within the Kapp Starostin Formation in Spitsbergen are fully refined: three species, S. protodraschei, A. polaris and Timaniella wilczeki, are confined to the lowermost Vøringen Member (late Artinskian–early Kungurian), whereas S. loveni dominates the overlying members with a much longer stratigraphical range (late Kungurian–Lopingian?). This abrupt compositional change, along with comparable changes in other taxonomic groups, can be explained by a palaeoclimatic shift from cool to cold conditions between the Vøringen Member and the overlying Svenskeegga member. A similar biotic transition is identified between the Hambergfjellet and Miseryfjellet formations in Bjørnøya. On the other hand, S. loveni is abundant in the Late Permian strata of central East Greenland, but there it appears to be more costate in plication compared to its counterpart from Spitsbergen. It is suggested that this alteration in shell ornamentation may represent a possible response (adaptation) to warming arising from the southward migration of the species.

http://zoobank.org/urn:lsid:zoobank.org:pub:85B863D2-DB42-4835-940A-2DE852C82178

这项研究报告了来自斯瓦尔巴特群岛的二叠纪岩石以及位于Pangaea北缘的邻近地区（加拿大的北极和俄罗斯的亚极乌拉尔）的各种螺旋藻腕足动物。总共识别并详细描述了四个属中的11种腕足动物，其中包括两个新种（原产的Spiriferella protodraschei和Arcullina？enokiani）。）。根据我们的分类学调查，尽管壳轮廓和宏观装饰存在相当大的种内差异，但每个物种内腹沟的形态特征和背褶相对稳定。此外，脓疱的排列，作为贝壳表面的微装饰，以及藻体覆盖物的发展，都具有重要的特征，可以推断系统发育关系并确定物种。在这里，最著名但仍存有疑问的分类单元是Spiriferella keilhavii，它是一种局限于Bjørnøya甚至可能仅限于东格陵兰中部的特有物种。它在系统发育上最接近S. loveni。继分类修订，在斯匹次卑尔根的卡普斯塔罗斯京地层内的spiriferellids的地层范围充分细化：三个品种，S. protodraschei，A.宝来和Timaniella wilczeki，被限制到最低Vøringen会员（晚亚丁斯克早孔古阶） ，而S. loveni上覆地层以较大的地层范围占主导地位（晚古古里安-罗平纪？）。这种突然的组成变化，以及其他分类学类别的可比变化，可以用弗林根成员与上覆的斯文斯基格成员之间从冷到冷的古气候变化来解释。在比约尔诺（Bjørnøya）的Hambergfjellet和Miseryfjellet地层之间也发现了类似的生物过渡。另一方面，S。loveni在东部格陵兰岛中部的二叠纪晚期地层中含量较高，但与斯匹次卑尔根州的对应物相比，它的褶皱成本更高。有人认为，壳饰的这种改变可能代表对物种向南迁移所引起的变暖的可能反应（适应）。

http://zoobank.org/urn:lsid:zoobank.org:pub:85B863D2-DB42-4835-940A-2DE852C82178