Endoxocrinus (Endoxocrinus) parrae

David, Jerome, Roux, Michel, Messing, Charles G. & Ameziane, Nadia, 2006, Revision of the pentacrinid stalked crinoids of the genus Endoxocrinus (Echinodermata, Crinoidea), with a study of environmental control of characters and its consequences for taxonomy, Zootaxa 1156, pp. 1-50 : 34-35

Endoxocrinus (Endoxocrinus) parrae [Gervais (in Guérin, 1835)]

Figures 4 b–f, 5a–c, 18, 19a, 20a.

Synonymy: Encrinus parrae Gervais (in Guérin, 1835): 49; Pentacrinus caput­medusae Müller, 1843 (pars):; Pentacrinus mülleri Oersted, 1856: 202 ; Pentacrinus (Neocrinus) mülleri Thomson, 1864: 7 ; Isocrinus parrae A.H. Clark, 1908a: 687 ; Endoxocrinus parrae A.H.Clark, 1908b: 151 ; Cenocrinus parrae Döderlein, 1912: 21 ; Diplocrinus carolinae A.H. Clark, 1934: 4 ; Endoxocrinus prionodes H.L. Clark, 1941: 6 ; Diplocrinus (Endoxocrinus) parrae Roux, 1978 : A9 (unpublished data); Endoxocrinus (Endoxocrinus) mülleri David, 1998: 203 (unpublished data) and Roux et al., 2002: 820; Endoxocrinus (Endoxocrinus) carolinae Roux et al., 2002: 820 ; Endoxocrinus (Endoxocrinus) prionodes Roux et al., 2002: 820 .

Emended diagnosis

A species of the subgenus Endoxocrinus showing a wide ecophenotypic variation with 96% IIBr2ax, 52–91% IIIBr3ax and 6–46% IIIBr2ax, 67–97% IVBr3ax, and 79–100% VBr3ax; arms smooth to serrated; arm number 23–58; stalk in adult pentalobate to pentagonal in cross­section; number of internodals per mature noditaxis usually 6–14 (mode in local populations 8–12); proximalmost diameter of stalk usually 4–5 mm, attaining 7 mm in largest specimens; usually 5 cirri per whorl, sometimes 4 or exceptionally fewer, with up to 44 cirrals (usually>30); cryptosymplexies flat or with a slight symmorphy of inner interpetaloid zone, with syzygial stereom predominating in interpetaloid zones, axial canal filled up by an irregular and variable network not clearly separated from perilumen, and preserving a small to large secondary lumen.

Type locality

Off Cuba.

Neotype: According to the preceding remarks, the specimen housed in the Zoological Museum, University of Copenhagen, and described by Oërsted (1856) as Pentacrinus mülleri , which was regarded as a junior synonym of E. parrae by A.H. Clark (1908a, 1908b, 1923), is designated as the neotype of E. parrae .

Occurrence

Western tropical Atlantic from the northern Bahamas to southern Brazil, and off eastern Yucatan, Nicaragua, and Venezuela, at depths from 154 to 971 m, chiefly between about 500 and 600 m in the Straits of Florida; a few anomalous shallower records (18–59 m) should be verified by further investigations (Meyer et al. 1978).

Remarks

According to David (1998), E. (E.) parrae exhibits three distinct ecophenotypes previously described and figured as separate species (i.e., Diplocrinus carolinae , Endoxocrinus parrae and Endoxocrinus prionodes ). We place these phenotypes at the rank of subspecies for practical reasons of nomenclature, as follows: 1) they were previously correctly described and named; 2) they are supported by the evidence of the polymodal statistical distribution of easily identified stalk characters.

For each subspecies, occurrences are only given for specimens that can be clearly determined, excluding specimens with intermediate morphology.

Included subspecies

Encrinus parrae Gervais (in Guérin, 1835) sensu stricto (= Pentacrinus mülleri Oersted, 1856 ); Endoxocrinus prionodes H.L. Clark, 1941 ; Diplocrinus carolinae A.H. Clark, 1934 .

Figures

FIGURE 4. The four phenotypes of diplocrinine crinoids in their environment off the Bahamas. (a): population of the minimus phenotype on the flank of a lithoherm (photo courtesy A. C. Neumann, Univ. North Carolina, taken from DSV Alvin), (b): one specimen of the prionodes phenotype between blocks at the Deep site, (c): a population of the parrae phenotype accompanied by a few Neocrinus decorus on the upcurrent slope of a large mound at the Middle Site, (d): one specimen of the parrae phenotype on a hardground slope at the Middle Site, (e): a population of the carolinae phenotype clinging to the overhanging edge of a block at the Deep Site, (f): three specimens of the phenotype carolinae attached to the side of a block at the Deep Site (photos b­f taken from Johnson Sea Link by C. G. Messing).