Freyella benthophila Sladen 1889
Creators: name: Zhang, Ruiyan
name: Zhou, Yadong
name: Mao, Jingwen
name: Wang, Chunsheng
name: Zhang, Dongsheng
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Echinodermata
Asteroidea
Brisingida
Freyellidae
Freyella
Freyella benthophila

description: Freyella benthophila Sladen, 1889
Fig. 11
Freyella benthophila: Sladen 1889: 641; Wood-Mason and Alcock 1891: 440; Alcock 1893: 121; Fisher 1928: 24; Madsen 1951: 84; Cherbonnier and Sibuet 1972: 1356; Sibuet 1975: 292; Korovchinsky and Galkin 1984: 1215 (in key); Galkin and Korovchinsky 1984: 165; Zhang et al. 2024: 17.
Freyellidea benthophila: Fisher 1917: 429.
Freyastera benthophila: Downey 1986: 36; McKnight 1993: 173; Mah 1998: 78; Mah in Clark and Mah 2001: 318; Dilman 2014: 38; Moreau et al. 2015: 16; Moreau et al. 2018: 147; Zhang et al. 2019: 7 (in key).
Belgicella racowitzana: Ludwig 1903: 59; Koehler 1907: 141; Koehler 1908: 245; Döderlein 1928: 293; Fisher 1928: 6; Fisher 1940: 75; A. M. Clark 1962: 68; Jangoux and Massin 1986: 91; Mah 1998: 78; Mah in Clark and Mah 2001: 317; Moreau et al. 2015: 5; Moreau et al. 2018: 147.
Material examined.
NHMUK 1890.5.7.1078 (holotype) (Fig. 11 A, B, E, G).
Other material.
IA 3-2168; MNHN -IE-2008-1057; MNHN -IE-2008-1073; MNHN -IE-2008-1081; MNHN -IE-2017-1829; MNHN -IE-2017-1948; MNHN -IE-2019-5752; MNHN -IE-2022-2192 (Fig. 11 D); MNHN -IE-2022-2193; MNHN -IE-2022-2194; MNHN -IE-2022-2195; MNHN -IE-2022-2196; NHMUK 9237 (Fig. 11 C, F, H, I); NOC 11908 # 44; NOC 12930 # 64; NOC 12930 # 78; NOC 13200 # 27; NOC 13200 # 60; NOC 52701 # 42; NOC 54901 # 7; NOC 54902 # 1; NOC 54903 # 1; SO 268-1_29_014; SO 268-2_109_189; SO 268-02 _ 99 _ 04. (Suppl. material 1).
Diagnosis.
Arms six. Abactinal armature of disk with one primary central plate at center of the disk and a primary interradial plate at each interradius (Fig. 11 A – D). Central and interradial primary plates shield-like, much larger than the rest of abactinal disk plates (primary plates present in most specimens examined, but indistinguishable in some individuals). Abactinal disk and arm plates evenly covered with numerous short spinelets and small pedicellariae (Fig. 11 G). Beyond genital area, abactinal arm with bands of small pedicellariae. Adambulacral plate with one subambulacral spine. Proximal subambulacral spines with modified tips (truncated or flattened bifurcated) (Fig. 11 E, H). Furrow spine absent. Oral plate with 2–3 actinostomal spines and one suboral spine, each covered with membranous sheath, but the tips are bare (Fig. 11 E, F). Spines covered with small pedicellariae. Large pedicellariae absent. Inferomarginal plates and lateral spines occur at alternate adambulacral plates beyond genital area (Fig. 11 I).
Distribution.
North Atlantic, Southern Pacific, Eastern Pacific, Southern Ocean. 2450–5000 m. Type locality: Southern Pacific, 4663 m.
Remarks on F. benthophila and other six-armed Freyella.
F. benthophila stands in a peculiar position by having shared morphological characters with both Freyastera and Freyella. As a species with six arms, it is readily distinguished from other Freyella species with more than six arms. Compared with other Freyastera, it is differentiated from most species by having many small spinelets on its abactinal disk and arms and distinguished from Freyastera mortenseni, F. delicata, and F. mexicana, which also bears multiple spines on abactinal plates, by the absence of furrow spines and more distantly located inferomarginal plates. Phylogenetic analysis put it within the Freyella clade (Fig. 12; Zhang et al. 2024), indicating that having six arms is not an autapomorphy of the Freyastera clade.
There are three other six-armed Freyella species whose taxonomic position needs to be re-evaluated, including F. oligobrachia H. L. Clark, 1920; F. hexactis Baranova, 1957; and F. vitjazi Korovchinsky & Galkin, 1984. F. oligobrachia and F. vitjazi have inferomarginals corresponding to alternate adambulacral plates according to their original descriptions; thus, they should be retained within Freyella. F. hexactis was described to have inferomarginal plates to every third adambulacrals, then to alternate adambulacrals, then at the end of the arm, to each adambulacral plate (Baranova 1957). It is difficult to justify it as either Freyella or Freyastera simply by this description. However, this species closely resembles F. oligobrachia and F. benthophila, as was shown in the key in Zhang et al. (2019). It is necessary to examine the types of F. oligobrachia and F. hexactis to be certain of their generic affinities and their relationship with F. benthophila. F. vitjazi, on the other hand, could be differentiated from the other six-armed Freyella species by having a diagonal line of three spines on each adambulacral plate. These three species are retained as Freyella for the time being, but they should be compared with in any future descriptions of six-armed freyellids.
description: Published as part of Zhang, Ruiyan, Zhou, Yadong, Mao, Jingwen, Wang, Chunsheng & Zhang, Dongsheng, 2025, Hidden diversity of Freyastera (Asteroidea, Brisingida, Freyellidae) at great depth: Description of new species and remarks on species boundaries, pp. 735-760 in Zoosystematics and Evolution 101 (2) on pages 735-760, DOI: 10.3897/zse.101.144918