Colossendeis is a genus of sea spider (class Pycnogonida) belonging to the family Colossendeidae. These sea spiders are typically found in the deep sea. This genus includes the largest pycnogonids, with leg spans frequently ranging from 40 to 50 cm (16-20 in). The largest sea spider, Colossendeis colossea, can reach a leg span of 70 cm (28 in). This genus also includes some bioluminescent sea spiders.
Description Sea spiders in this genus feature an unsegmented trunk, a low ocular tubercle, and a well-developed abdomen. Chelifores are absent in adults. The palps and ovigers touch at their bases, and the strigilis is tightly curved with a strong terminal claw. Species in this genus have only four pairs of legs. The ventral surface of the second most proximal article (second coxa) of some or all of these legs features tiny genital pores.
Feeding Sea spiders in this genus feed on cnidarians, sponges, bryozoans, small mollusks, and small polychaetes.
Phylogeny Although all species in this genus are eight-legged, phylogenetic analysis based on molecular data indicates that this genus is paraphyletic with respect to the ten-legged genus Decolopoda and the twelve-legged genus Dodecolopoda; these two polymerous (extra-legged) genera are nested within the genus Colossendeis in a phylogenetic tree. This paraphyly would normally make both Dodecolopoda and Colossendeis junior synonyms of Decolopoda, the oldest name, and require all three genera to merge under the name Decolopoda. To avoid this disruption, authorities keep these genera under different names and retain Colossendeis as a paraphyletic genus.
The molecular evidence also indicates that both Decolopoda and Dodecolopoda are nested within a monophyletic group containing the "longitarsal" species in the genus Colossendeis. The sea spiders in this "longitarsal" clade feature legs in which the three most distal articles (claw, propodus, and tarsus) taken together are at least three-quarters the length of the fourth most distal article (second tibia). This clade includes not only Antarctic species of Colossendeis such as C. australis and C. glacialis but also widespread taxa such as C. megalonyx and C. robusta. In "brevitarsal" species, such as C. macerrima, the three most distal articles are instead much shorter relative to the second tibia.
Species There are 72 species:
Colossendeis acuta Stiboy-Risch, 1993 Colossendeis adelpha Child, 1998 Colossendeis angusta Sars, 1877 Colossendeis aperta Turpaeva, 2005 Colossendeis arcanus Turpaeva, 2008 Colossendeis arcuata A. Milne-Edwards, 1885 Colossendeis australis Hodgson, 1907 Colossendeis avidus Pushkin, 1970 Colossendeis belekurovi Pushkin, 1993 Colossendeis bicincta Schimkewitsch, 1893 Colossendeis bouvetensis Dietz, Pieper, Seefeldt & Leese, 2015 Colossendeis brevirostris Child, 1995 Colossendeis bruuni Fage, 1956 Colossendeis clavata Meinert, 1899 Colossendeis colossea Wilson, 1881 Colossendeis concedis Child, 1995 Colossendeis cucurbita Cole, 1909 Colossendeis curtirostris Stock, 1963 Colossendeis dalli Child, 1995 Colossendeis drakei Calman, 1915 Colossendeis elephantis Child, 1995 Colossendeis enigmatica Turpaeva, 1974 Colossendeis ensifer Child, 1995 Colossendeis fijigrypos Bamber, 2004 Colossendeis fragilis Pushkin, 1993 Colossendeis gardineri Carpenter, 1907 Colossendeis geoffroyi Mane-Garzon, 1944 Colossendeis glacialis Hodgson, 1907 Colossendeis gracilis Hoek, 1881 Colossendeis grassus Pushkin, 1993 Colossendeis hoeki Gordon, 1944 Colossendeis insolitus Pushkin, 1993 Colossendeis korotkevitschi Pushkin, 1984 Colossendeis kurtchatovi Turpaeva, 1993 Colossendeis leniensis Pushkin, 1993 Colossendeis leptorhynchus Hoek, 1881 Colossendeis longirostris Gordon, 1938 Colossendeis losinskii Turpaeva, 2002 Colossendeis macerrima Wilson, 1881 Colossendeis media Hoek, 1881 Colossendeis megalonyx Hoek, 1881 Colossendeis melancholicus Stock, 1975 Colossendeis mica Pushkin, 1970 Colossendeis microsetosa Hilton, 1943 Colossendeis minor Schimkewitsch, 1893 Colossendeis minuta Hoek, 1881 Colossendeis mycterismos Bamber, 2004 Colossendeis nasuta Hedgpeth, 1949 Colossendeis notialis Child, 1995 Colossendeis oculifera Stock, 1963 Colossendeis peloria Child, 1994 Colossendeis perforata Turpaeva, 1993 Colossendeis pipetta Stock, 1991 Colossendeis potentis Turpaeva, 2008 Colossendeis proboscidea (Sabine, 1824) Colossendeis pseudochelata Pushkin, 1993 Colossendeis robusta Hoek, 1881 Colossendeis rostrata Turpaeva, 1994 Colossendeis scoresbii Gordon, 1932 Colossendeis scotti Calman, 1915 Colossendeis sinuosa Stock, 1997 Colossendeis spicula Child, 1994 Colossendeis stramenti Fry & Hedgpeth, 1969 Colossendeis subminuta Schimkewitsch, 1893 Colossendeis tasmanica Staples, 2007 Colossendeis tenera Hilton, 1943 Colossendeis tenuipedis Pushkin, 1993 Colossendeis tethya Turpaeva, 1974 Colossendeis tortipalpis Gordon, 1932 Colossendeis vityazi Turpaeva, 1973 Colossendeis weddellensis Turpaeva, 2008 Colossendeis wilsoni Calman, 1915
References
Further reading Manfred Moritz: Ordnung Colossendeomorpha in: Urania Tierreich. Wirbellose Tiere 2. Urania-Verlag, Berlin 2000; Seite 327. . Tomás Munilla, Anna Soler Membrives: Check-list of the pycnogonids from Antarctic and sub-Antarctic waters: zoogeographic implications. Antarctic Science (2008) 1-13