Bathymetrinae

Phrixometra nutrix, copyright Pablo E. Penchaszadeh.

Belongs within: Antedonacea.

The Bathymetrinae are a group of feather stars with moderate-sized cirri arising from small, closely placed sockets, and arms branching once only.

Characters (from Wienberg Rasmussen 1978): Centrodorsal conical or rounded subconical to low hemispherical. Cirrus sockets rather small, closely placed, often numerous (25 to more than 100), covering almost completely sides of centrodorsal, rarely few (10-15) with mostly smooth cirrus-free doral area; cirri closely alternate, generally without distinct arrangement, often interpreted as alternating circles, but sometimes with tendency to form columns, up to 30 in number. Size of sockets may increase slightly upward. Length of cirri moderate, apical cirri rather short. Cirrals laterally compressed and generally long, length one to six times width. Distal cirrals often dorsally carinate, may have dorsal spine. Centrodorsal cavity large. Basal rosette, no rod-shaped basals. Radials may have smooth, rather large, free surface in small species, but generally very low and often concealed in midradial area of large species. Articular face of radials high and rather steep. Interarticular ligament fossae triangular or low and narrow ridge separating interarticular from ventral fossae may be almost horizontal, straight or curved. Ventral muscular fossae large and high, rounded subtriangular with rounded ventral edge, separated by low and narrow median ridge and small notch, forming angle of almost 90 degrees with each other. Radial cavity narrow. Arms divided at primibrachs 2 only. Synarthrial articulation at primibrachs 1-2 often embayed. Primibrachs 1 usually with parallel or converging sides, commonly laterally overhung by primibrachs 2. First pinnule stiff and slender with elongated pinnulars.

<==Bathymetrinae
    |--Boleometra Clark 1936 WR78
    |    `--*B. clio (Clark 1907) [=Antedon clio] WR78
    |--Fariometra Clark 1917 WR78
    |    `--*F. explicata (Clark 1908) [=Trichometra explicata] WR78
    |--Nepiometra Clark 1917 WR78
    |    `--*N. laevis (Carpenter 1888) [=Antedon laevis] WR78
    |--Orthometra Clark 1917 WR78
    |    `--*O. hibernica (Clark 1913) [=Trichometra hibernica] WR78
    |--Retiometra Clark 1936 WR78
    |    `--*R. alascana Clark 1936 WR78
    |--Thaumatometra Clark 1908 WR78
    |    `--T. tenuis (Clark 1907) [=Antedon tenuis; incl. A. ciliata Clark 1907, *Thaumatometra ciliata] WR78
    |--Tonrometra Clark 1917 WR78
    |    `--*T. remota (Carpenter 1888) [=Antedon remota] WR78
    |--Bathymetra Clark 1908 WR78
    |    |--*B. abyssicola (Carpenter 1888) [=Antedon abyssicola] WR78
    |    `--B. carpenteri Clark 1908 MG-H11
    |--Hathrometra Clark 1908 WR78
    |    |--H. tenella (Retzius 1783) WR78 (see below for synonymy)
    |    `--H. sarsi [=Antedon sarsi] BK77
    |--Trichometra Clark 1908 WR78
    |    |--T. cubensis (Pourtalès 1869) [=Antedon cubensis; incl. *T. aspera Clark 1908] WR78
    |    `--T. delicata BK77
    `--Phrixometra Clark 1917 WR78
         |--*P. longipinna (Carpenter 1888) [=Antedon longipinna] WR78
         |--P. exigua WR78
         `--P. nutrix B78

Hathrometra tenella (Retzius 1783) WR78 [=Asterias tenella WR78; incl. Alectro dentata Say 1825 WR78, Antedon dentata BK77, *Hathrometra dentata WR78]

*Type species of generic name indicated

REFERENCES

[BK77] Barel, C. D. N., & P. G. N. Kramers. 1977. A survey of the echinoderm associates of the north-east Atlantic area. Zoologische Verhandelingen 156: 1–159.

[B78] Breimer, A. 1978. General morphology: recent crinoids. In: Moore, R. C., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt T. Echinodermata 2. Crinoidea vol. 1 pp. T9–T58. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[MG-H11] McEnnulty, F. R., K. L. Gowlett-Holmes, A. Williams, F. Althaus, J. Fromont, G. C. B. Poore, T. D. O’Hara, L. Marsh, P. Kott, S. Slack-Smith, P. Alderslade & M. V. Kitahara. 2011. The deepwater megabenthic invertebrates on the western continental margin of Australia (100–1100 m depths): composition, distribution and novelty. Records of the Western Australian Museum Supplement 80: 1–191.

[WR78] Wienberg Rasmussen, H. 1978. Articulata. In: Moore, R. C., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt T. Echinodermata 2. Crinoidea vol. 3 pp. T813–T927. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).