Echinopsolus Gutt 1990

1. Echinopsolus Gutt, 1990.

Bohn & Hess (2014) reassigned a group of Antarctic cucumariid species to genus Echinopsolus Gutt, 1990, based on their shared and unique set of morphological characters related to their reproductive mode. The group comprised: Echinopsolus acanthocola Gutt, 1990; E. acutus (Massin, 1992); E. charcoti (Vaney, 1906); E. koehleri (Vaney, 1914); E. mollis (Ludwig & Heding, 1935); E. parvipes (Massin, 1992); E. splendidus (Gutt, 1990). In the same paper Bohn & Hess (2014) reassigned genus Echinopsolus to family Cucumariidae.

TaxonType statusStationcollectedLocalitycollectedDepthDatecollectedInstitution lodgedRegistrationClarkiella discoveryiHeding (in Heding & Panning, 1954) 1Holotype D 474 W of Shag Rocks South Georgia 199 m 19 Nov 1930 ZMUC HOL–000064Clarkiella discoveryiHeding, 1954 1Paratype D 474 W of Shag Rocks South Georgia 199 m 19 Nov 1930 ZMUC HOL–000247Parathyonidium incertumHeding (in Heding & Panning, 1954) 2, 3Holotype 3Lost specimen 3HOL–000093Parathyonidium incertumHeding, 1954 Paratypes (3) D 170 Clarence Island 342 m 23 Feb 1927 ZMUC HOL–000300Parathyonidium incertumHeding, 1954 Paratypes (3) D 170 Clarence Island 342 m 23 Feb 1927 NHMUK NHMUK 2011.171–173Parathyonidium incertumHeding, 1954 Partypes (2) No record Elephant Island 600 m No record MNHN MNHN– IE–2013–2479 S Shetland Islands

1 No Discovery station data were reported for Clarkiella discoveryi with the description of the new taxa in Heding & Panning 1954, but registered and labelled holotype and paratype (one) specimens are in the ZMUC with type status, station number and collection data (see Table 2 above with station data from the labels with the types in the ZMUC). Both type specimens were collected from the same type locality, station D474.

2 The station data reported for the type for Parathyonidium incertum in Heding & Panning (1954) is station D474. We judge that this may be a mistake since it is the type locality on the labels for Clarkiella discoveryi. The holotype specimen is assumed to be lost as no “holotype” has been found. But there are paratypes from station D170, and a note on the label with them translated by Tom Schioette in 2013 reads: “Does the identification with them include also the large specimens? Heding’s serial number 234–236 st. 170”. With some reservation we judge that the holotype was most probably also from the paratype station D170, and not station D474 as published in Heding & Panning (1954).

3 Note by Tom Schioette in 2013: “The holotype of Parathyonidium incertum, which should probably have been (or perhaps was) returned with the “Discovery” material after Heding’s death, was later given the ZMUC number HOL-93 in absentia. It must probably be considered lost, since later workers on the material have not succeeded in finding it”.

1 See Systematic note 6 below. This entry has been changed from the O’Loughlin & VandenSpiegel 2010 paper.

O’Loughlin et al. (2009a) discussed the “ Cucumaria georgiana (Lampert, 1886) group” of Antarctic species that was created by Gutt (1988), and followed by Massin (1992). O’Loughlin et al. (2009a) listed 11 species in this “group”: Cucumaria acuta Massin, 1992; Cucumaria analis Vaney, 1908; Cucumaria aspera Vaney, 1908; Cucumaria attenuata Vaney, 1906; Cucumaria georgiana (Lampert, 1886); Cucumaria joubini Vaney, 1914; Cucumaria lateralis Vaney, 1906; Cucumaria perfida Vaney, 1908; Cucumaria periprocta Vaney, 1908; Cucumaria secunda Vaney, 1908; Cucumaria vaneyi Cherbonnier, 1949. Bohn & Hess (2014) also discussed this “group”, and we agree that the systematic status of the species in this group requires resolution. Foundational to this systematic resolution must be an establishment of the systematic status of Cucumaria georgiana (Lampert, 1886). Bohn & Hess (2014) did not assign the “group” to Echinopsolus. We have assigned some Discovery Expedition lots to this “group”. Based on the general similarity of their reproductive morphological features with those of the Echinopsolus species we have also assigned this “group” to Echinopsolus.

Bohn & Hess (2014) were not able to confirm the systematic status of Echinopsolus excretiospinosus Massin, 2010, but noted that no brood pouches were reported and the ventral tentacle pair were apparently not smaller than the other tentacles.

CO1 genetic data (Gustav Paulay pers. comm.; see phylogenetic tree in O’Loughlin et al. 2011) support a generic clade that includes Echinopsolus acanthocola (with apparently two or three cryptic species with geographic congruence), the “ georgiana group” (with apparently two or three cryptic species with geographic congruence), and the reassigned Echinopsolus mollis (apparently two or three cryptic species with geographic congruence). Generic data thus support in part the work of Bohn & Hess (2014). We note that these species also have mid-body dorsal papillae or tube feet, and lack cup (bowl) ossicles in the body wall.

But CO1 genetic data (Gustav Paulay pers. comm.; see phylogenetic tree in O’Loughlin et al. 2011) support a generic clade for Psolus koehleri and Psolus charcoti that is separate from the Echinopsolus clade and do not support the reassignment of these two species to Echinopsolus. We note that these two species lack mid-body dorsal tube feet or papillae, and do have cup (bowl) ossicles in the body wall. Genetic data to date do not support their assignment to a Psolus Oken, 1815 clade. We leave these two species in their current reassignment to Echinopsolus until a necessary reassessment of dendrochirotid generic assignments is supported by additional genetic data.

We do not have a CO1 sequence for the recently reassigned Echinopsolus splendidus. This species lacks dorsal and lateral tube feet / papillae, but also lacks cups / bowls in the body wall. It falls morphologically into neither Echinopsolus genetic /generic clade. We judge that it will probably fall into another generic clade but in the absence of supportive genetic data we do not change the current reassignment to Echinopsolus.