Description of Barathricolathermophilus, a new species from a deep-sea hydrothermal vent field in the Indian Ocean with redescription of the Barathricola type species (Crustacea, Copepoda, Cyclopoida).

Viatcheslav N Ivanenko,Cheon Young Chang,Il-Hoi Kim,Jimin Lee

doi:10.3897/zookeys.865.35827

Abstract

Re-study of the type species of the genus Barathricola Humes, 1999 (Copepoda, Cyclopoida, Schminkepinellidae) described from the Pacific Ocean (Juan de Fuca Ridge), and study of the species Barathricolathermophilussp. nov. from a deep-sea hydrothermal vent field on the Central Ridge in the Indian Ocean revealed a derived feature and widespread geographic distribution of this deep-sea genus of cyclopoids. The derived feature of Barathricola is the sexually dimorphic third endopodal segment of leg 3 possessing a small outer terminal spine together with spine-like outgrowths on this segment. The new species differs from Barathricolarimensis Humes, 1999 in not expressing sexual dimorphism in leg 5, having three spines and one seta on its exopod in both sexes (B.rimensis has three spines and one seta on the female exopod but three spines and two setae on the male exopod) and in having broader caudal rami which are 8.9 times longer than wide in the female (this ratio for B.rimensis is 11). An amended diagnosis of the genus Barathricola, a key and a table of morphological differences for all species of Schminkepinellidae are given.

Highlights

Cyclopoids of the family Schminkepinellidae were discovered in the deep-sea and in marine caves (Martínez Arbizu 2006)
A molecular analysis conducted by Khodami et al (2017) placed Schminkepinellidae as the sister group of Poecilostomatoida but was not verified by the analysis of Mikhailov and Ivanenko (2019) based on data provided by the authors
Karanovic (2008) described Cyclopinella tincanbayensis as a new species and synonymized two monotypic genera Muceddina and Barathricola with Cyclopinella and included these genera within Cyclopinidae based on the two major characters as synapomorphic shared by these nominal genera and Cyclopinella: the third endopodal segment of leg 4 with all armature elements transformed into spines and the three-segmented female leg 5 with an uniform armature and the elongate exopod

Summary

Introduction

Cyclopoids of the family Schminkepinellidae were discovered in the deep-sea and in marine caves (Martínez Arbizu 2006). Leg 1 (Fig. 2C) basis with seven thick setules on inner margin; inner distal spine large, 48 μm long, extending to middle of third endopodal segment, spinulose along both margins.

Results

Conclusion