Malacosaccus coatsi Topsent 1910

• Main Authors: Janussen, Dorte, Reiswig, Henry M.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2009
• Subjects: Biodiversity; Taxonomy; Animalia; Porifera; Hexactinellida; Lyssacinosida; Euplectellidae; Malacosaccus; Malacosaccus coatsi; Antarc*; Antarctica; Weddell Sea
• Online Access: https://doi.org/10.5281/zenodo.5611960; http://treatment.plazi.org/id/434A87A6FFB3FFD4FF53FB8FFEA08BB0

Malacosaccus coatsi Topsent, 1910 (Figs. 1 B, 2 & 3, Table 1) Material examined: SMF 10702, ANDEEP III, R.V. 'Polarstern' stn PS67/102-11, Weddell Sea, Antarctica, 0 6 Mar. 2005, 65°35.40'–35.51'S, 36°29.00'–28.83'W, 4794–4797 m; ANDEEP III, SMF 10521, SMF 10703, SMF 10704, R.V. 'Polarstern', stn PS67/121-7, Weddell Sea, Antarctica, 14 Mar. 2005, 63°34.92'–34.65'S, 50°41.97'–41.68'W, 2616–2617 m. Description: Specimens were collected from two trawl stations, a single large nearly intact cup torn from the missing stalk (Fig. 2 A) from the first station and another specimen with stalk and root intact but with upper cup slightly damaged (Fig. 1 B) and two smaller fragments from the second station. The first specimen is 91 mm tall, 102 mm in diameter with a wall up to 25 mm in thickness. The second specimen is a stalked cup, total height 495 mm, upper cup width 234 mm, stalk 258 mm long by 41 mm diameter, root ball 152 mm diameter. The external surfaces of the upper body of both specimens are heavily mud-laden and woolly in appearance; the atrial surfaces are penetrated by apertures of exhalant canals, 1–8 mm in diameter (Fig. 2 A). Megascleres of both specimens are were found to be essentially identical; only those of the first specimen (station 102-11) were examined in detail (measurements given in Table 1). Dermalia and atrialia are pinular hexactins (Figs. 2 B, 3A) with scale-like, distal-pointed spines on the long, smoothly tapered, inflated pinular ray. All other rays are smooth and cylindrical, with rounded or parabolic tips. Principalia are very large hexactins (Fig. 3 B) and pentactins (Fig. 3 C), about equal in abundance. Their rays are smooth and cylindrical, terminating in rounded or slightly parabolic tips. Large triactins and stauractins are additionally present in the stalk of specimen 2; their rays are similar in form to the principalia of the body. No diactine megascleres are present and the only spines occurring are on the pinular ray of dermalia and atrialia. Microscleres of both specimens ...