Department for Innovation in Biological, Agro-food and Forest systems, Tuscia University. Largo dellUniversit snc, 01100 Viterbo, Italy. .
Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, 38098 S. Michele allAdige (TN), Italy. .
Zootaxa. 2021 Sep 29;5047(2):177-191. doi: 10.11646/zootaxa.5047.2.7.
We describe a new harpacticoid, Stammericaris remotaepatriae sp. nov., collected from the hyporheic habitat of a stream in Nantucket, MA, USA. The new species is characterized by the size of the caudal rami of both sexes, which are shorter than the anal somite, by the morphology and armature of the P3 and, mainly, by the P4 endopod of males, represented by a curved plate with a strongly bifid tip, the distal proximal outgrowth of the distal margin spiniform and denticled, the proximal outgrowth missing. The study of the new species allowed us to review the systematic position of Parastenocaris palmerae Reid, 1992, which we transferred to Stammericaris Jakobi, 1972 as Stammericaris palmerae (Reid, 1992) comb. nov., based mainly on the structure of the male P4 endopod complex and the setation of the caudal rami. We also discussed the taxonomic position and affinities of Parastenocaris trichelata Reid, 1955, suggesting that this species is related to the two former ones for a set of diagnostic features, but can not be attributed to the genus due to the peculiar morphology of the male P4 endopod complex; P. trichelata is therefore considered species inquirenda. We also discussed Parastenocaris sp. 1 and Parastenocaris sp. 3, two taxa only partially described and drawn in Strayer (1988). In fact, Parastenocaris sp. 1 can be related to Stammericaris and might represent a third species of the genus in the Nearctic region. Remarkably, the structure of the male P4 endopod of Parastenocaris sp. 3 is typical of Proserpinicaris Jakobi, 1972; this hypothetical assignment of the species to Proserpinicaris, if confirmed, would be of relevant taxonomic and biogeographic value. Finally, we provide an updated distribution map of the genus Stammericaris and brief remarks on the faunistic and ecological characteristics of the taxa presented and discussed in this paper.
我们描述了一种新的桡足类动物，Stammericaris remotaepatriae sp. nov.，它来自美国马萨诸塞州楠塔基特岛溪流的底层栖息地。新种的特征是两性尾叉的大小，比肛后体节短，P3 的形态和装备，主要是雄性 P4 内附肢，由一个弯曲的板组成，具有强烈分叉的尖端，远端边缘的近端突起呈刺状和锯齿状，近端突起缺失。对新种的研究使我们能够重新审查 Parastenocaris palmerae Reid, 1992 的系统位置，我们将其转移到 Stammericaris Jakobi, 1972 作为 Stammericaris palmerae (Reid, 1992) comb. nov.，主要基于雄性 P4 内附肢复合体的结构和尾叉的刚毛。我们还讨论了 Parastenocaris trichelata Reid, 1955 的分类位置和亲缘关系，表明该种与前两种具有一系列诊断特征有关，但由于雄性 P4 内附肢复合体的特殊形态，不能归入属；因此，P. trichelata 被认为是待查种。我们还讨论了 Parastenocaris sp. 1 和 Parastenocaris sp. 3，这两个分类单元仅在 Strayer (1988) 中部分描述和绘制。事实上，Parastenocaris sp. 1 可能与 Stammericaris 有关，可能代表北美地区该属的第三个种。值得注意的是，Parastenocaris sp. 3 的雄性 P4 内附肢的结构是典型的 Proserpinicaris Jakobi, 1972；如果确认该物种的这种归属，将具有重要的分类和生物地理价值。最后，我们提供了 Stammericaris 属的更新分布地图，并简要讨论了本文提出和讨论的分类单元的区系和生态特征。
