Freyastera sexradiata ( Perrier, 1885 )

Freyastera sexradiata ( Perrier, 1885) View in CoL

Freyella sexradiata View in CoL : Perrier 1885: 6; 1894: 89; Koehler 1909: 129; Grieg 1921: 30; Mortensen 1927: 129; Fisher 1928: 24; Madsen 1951: 84; Cherbonnier and Sibuet 1972: 1356; Korovchinsky and Galkin 1984: 1213 (in key); Galkin and Korovchinsky 1984: 167.

Freyellidea sexradiata : Fisher 1917: 429.

Freyastera sexradiata View in CoL : Downey 1986: 40; Clark and Downey 1992: 481; Mah 1998: 87; Mah in Clark and Mah 2001: 318; Dilman 2014: 38; Zhang et al. 2019: 6 (in key).

Material examined.

MNHN -IE-2014-165 (holotype) . MOM -81 0428 . (Suppl. material 1) .

Diagnosis.

Arms six. Abactinal disk plate, each with one fairly elongated spine. Pedicellariae absent on abactinal disk. Abactinal arm plates each bears one spine, covered with a membranous sheath loaded with small pedicellariae. Each adambulacral plate with one small aboral furrow spine and one subambulacral spine. Lateral spines corresponding to each adambulacral plate beyond genital area. Oral plate with two actinostomal spines, one suboral spine, and one aboral spine along the furrow margin.

Distribution.

North Atlantic, 4020–5110 m. Type locality: Between the Azores and France, 4060 m.

Remarks.

F. sexradiata is the type species of the genus. The holotype was examined in the present study, which demonstrates the key characters of the species as described by Perrier (1885, 1894), including having abactinal arm plate with one long spine, adambulacral plate with one subambulacral spine and one small aboral furrow spine, oral plate with two actinostomal spines, one suboral spine, and one aboral furrow spine. The arrangement of inferomarginal plates was not described in F. sexradiata ( Perrier, 1885, 1894), and the holotype was too broken to be examined for such a character. Based on the drawings in Perrier (1894), the inferomarginal plates appear at each adambulacral plate beyond genital area. Another specimen examined ( MOM - 81 0428) also has continuous inferomarginal plates beyond genital area. The photos of the holotype of F. sexradiata are available on the MNHN collection website (holotype: https://science.mnhn.fr/institution/mnhn/collection/ie/item/2014-165).