Placospongia anthosigma (Tanita & Hoshino, 1989)

Becking, Leontine E., 2013, Revision of the genus Placospongia (Porifera, Demospongiae, Hadromerida, Placospongiidae) in the Indo-West Pacific, ZooKeys 298, pp. 39-76 : 44-45

Placospongia anthosigma (Tanita & Hoshino, 1989) Figure 3

Geodinella anthosigma Tanita & Hoshino, 1989: fig. 16, Plate III fig. 1

Material examined.

Holotype. NSMT-Po R288 (National Museum of Nature and Science, Tokyo, Japan), Japan, Kannonzuka-dashi, Amadaiba, Sagami Bay, 62-67m. depth.

Description.

HolotypeNSMT-Po R288 encrusting specimen in three pieces of 1-2cm2 and 5mm thick, beige to pink in alcohol (Figure 3A).

Spicules. Megascleres large tylostyles with blunt point 520-797-930 × 15-18-20 × 18-20-23 μ m, small tylostyles with blunt point 250-320-410 × 10-12-18 × 13-14-18 μ m; microscleres selenasters 85-90-98 × 70-73-80 μ m,spherasters 15-19-25 μ m, stout spirasters with two or three contortions and acanthose spines spirally placed on shaft 8-11-18 × 3-4.5-5 μ m (Fig. 3)

Skeleton. As description of genus with addition that spirasters form a layer over and amidst the selenaster cortex and are also prevalent in choanosomal tissue. Spherasters amidst selenaster cortex and dispersed in choanosome.

Distribution.

Typelocality Sagami Bay, Eastern Japan, presently not recorded from any other locality.

Ecology.

On rock substrate in deep temperate waters.

Remarks.

Originally described by Tanita and Hoshino (1989) as Geodinella anthosigma . Geodinella is no longer a valid genus. Geodinella anthosigma should be transferred to the genus Placospongia based on the external morphology with the characteristic cortical plates and the presence of selenasters, tylostyles and spherasters. Placospongia anthosigma is distinguished from the other Indo-Pacific Placospongia spp. by the presence of contorted, spirally ornamented spirasters referred to by Tanita and Hoshino (1989) as ‘anthosigma’ and the small class of tylostyles with blunt points.