Colossendeis arcuata A. Milne-Edwards, 1885

Staples, David A., 2007, A new species of Colossendeis (Pycnogonida: Colossendeidae) together with records from Australian and New Zealand waters, Memoirs of Museum Victoria 64, pp. 79-94 : 80-87

Colossendeis arcuata A. Milne-Edwards, 1885

Figures 1A–J , 7C, D .

Colossendeis arcuatus A. Milne-Edwards, in Filhol, 1885:151 , fig. 48.

Colossendeis arcuata Stock, 1978: 403—405 , fig. 1g –j [earlier synonymy]; Stock, 1986: 417 — Bamber, 1983: 71–72, fig. 5; Bamber, 2004, 6— Child, 1992: 41; Child, 1998, 56— Bamber and Thurston, 1993: 859; Bamber and Thurston, 1995:143–45, fig. 9E.

Material examined. South Australia. Investigator Group , approx 75 n miles SSW of Pearson I., 35°08'S, 132°47'E, 1000 m, trawled, 1989, SAM E3383 (1 specimen) . Approx 100 n miles SSE of Cape de Covedic, Kangaroo I., 37°S, 137'E, 900–1000 m, trawled, FV Comet, G. Newton, 14–8 Feb 1988, SAM E3384 (1 specimen) . Approx. 120 n miles SW of CapeAdieu, GreatAustralian Bight , 33°58'S, 131°22'E, 1000 m, trawled, FV Saxon Progress, P. Wheenan, Nov 1989, SAM E3385 (1 specimen) . Due SW of Kangaroo I., approx. 36°10'S, 135°45'E, 1060 m, ‘orange roughy’ trawl, G. Newton, July 1988, SAM E3387 (1 specimen) . Western Australia. Approx. 11 n miles due S of Eucla, Great Australian Bight , 33°31'S, 128°49'E, 1059–1914 m, FV Longva 111, K. Gowlett-Holmes, 10 Dec 1989, SAM E3386 (1 specimen) .

Diagnosis. A large, robust species. Trunk and proboscis covered in tiny but mostly inconspicuous, spinules. Ocular tubercle lowly conical in lateral view, two large eyes on the sloping anterior surface, unpigmented in preserved material. Proboscis 1.25–1.50 times length of the trunk, robust, down-curved throughout its length. Abdomen clavate, articulated with trunk. Palp segment 3 longest, segment 5 less than half length segment 3, distal segments characteristically doubly-recurved. Oviger claw linear, gently curved. Legs; tarsus about three-quarters length of propodus, claw less than one quarter propodus length.

Distribution. Cosmopolitan. Depth 730–2177 m.

Type locality. W of Moroccan Coast. Remarks. These specimens agree in all respects with previous observations. Scattered cone-shaped pits each with a single median spine surround the oral surface and presumably serve a sensory function (fig. 7D). The down-curved proboscis of this species resembles C. rostrata Turpaeva, 1994 from which it otherwise differs in the proportions of palp segments 3 and 5 and by having the trunk and legs covered in small spines; the slightly taller spines on the leg segments are interspaced by 5–7 shorter spines. The leg span is about 400 mm. Coxal pellicula are present on all legs. Genital pores (fig. 7C) tiny, round, on distoventral surface of coxa 2 of all legs.

This is the first record for Australian waters, although it has been recorded from nearby New Zealand ( Child, 1998).

Figures

Figure 1. Colossendeis arcuata (SAM E3384): A, B, trunk, dorsal and ventral views of trunk; C, cephalon, lateral; D, palp; E, oviger; F, oviger claw; G, leg 3; H, propodus and claw; I, coxa 2 and genital pore; (SAM E3383); J, abdomen.

Figure 7. A. Colossendeis colossea, dorsal (Photo Gowlett-Holmes, CSIRO) B. Colossendeis melancholicus. (J40746), coxal pellicula. (Photo D.A. Staples) C. Colossendeis arcuata (SAM E3383) genital pore, leg 3. D. Colossendeis arcuata (SAM E3383) sensory setae, oral surface. (Photos D.A. Staples)