Boonyanusith Chaichat, Wongkamhaeng Koraon, Athibai Sujeephon
School of Biology, Faculty of Science and Technology, Nakhon Ratchasima Rajabhat University, Nakhon Ratchasima 30000, Thailand Nakhon Ratchasima Rajabhat University Nakhon Ratchasima Thailand.
Department of Zoology, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand Kasetsart University Bangkok Thailand.
Zookeys. 2020 Jan 16;904:1-22. doi: 10.3897/zookeys.904.37609. eCollection 2020.
A new species of Calanoida belonging to the genus Fosshagen & Iliffe, 1989 was found in a freshwater pool within a cave of the Satun province, South Thailand. It is the first record of the genus and of a stygobiotic representative of calanoid fauna in this country. The new species is most similar to Fosshagen & Iliffe, 1989, based on position of genital pores, structures of P4 and P5 in both sexes, relative length of subapical spine vestige on the male right P5, and shape of the male left P5 endopods. However, this new species is distinguished from its known congeners by: (1) relatively longer distal outer spines on the male right P5 exopods, (2) smaller endopods of the male left P5 and (3) elongated apical spines on the distal exopodal segment of the female P4 and P5. Furthermore, the distinctive characteristic of the Thai is the presence of inner minute seta on the distal segment of the male right P5 exopod. Detailed descriptions of the new species and a key to all six known species of the genus is provided.
1989年发现了一种属于Fosshagen & Iliffe属的新哲水蚤目物种，该物种发现于泰国南部沙敦府一个洞穴内的淡水池塘中。这是该国该属以及哲水蚤类洞穴生物代表的首次记录。基于生殖孔位置、两性的P4和P5结构、雄性右P5亚顶端刺痕的相对长度以及雄性左P5内肢的形状，该新物种与Fosshagen & Iliffe（1989年）最为相似。然而，该新物种与其已知同属物种的区别在于：（1）雄性右P5外肢上相对较长的远端外刺；（2）雄性左P5较小的内肢；（3）雌性P4和P5远端外肢节上细长的顶端刺。此外，泰国新物种的独特特征是雄性右P5外肢远端节上存在内部微小刚毛。文中提供了该新物种的详细描述以及该属所有六个已知物种的检索表。
