Solaster sp. 2

Mah, Christopher L., 2022, New Genera, Species and Occurrences of Deep-Sea Asteroidea (Valvatacea, Forcipulatacea, Echinodermata) collected from the North Pacific Ocean by the CAPSTONE Expedition, Zootaxa 5164 (1), pp. 1-75 : 67

Solaster sp. 2

FIGURE 23D

Comments. This species is distinguished by its 10 to 11 thick rays (not all are in view), bare patches present within each arm interradius and elongate, slender paxillae present on the abactinal surface with a distinct, serial series of large paxilliform marginal plates. Color was golden yellow with darker shades of orange proximally on the disk with lighter yellow distally on the arm.

Based on its external morphology, this seems most likely attributable to the genus Solaster . Rhipidaster is comparable in appearance and occurs at this depth range but a survey of R. vaneyi records ( Mah and Fujita 2020) has not shown individuals with more than seven rays. There are no records of Solasteridae from the Marianas Islands, making this the first record for this family from this region.

Ecological Observations. This species was observed with the body hunched over a probable sea-urchin prey item with the arms curved around and under the body. Adjacent to the observed individual were several disarticulated primary and secondary spines (Urspine in Fig. 23D ) as well as living individuals of Caenopedina (Pedinidae) . At least three other individuals of this urchin were present nearby suggesting a food source. This appears to be the first instance of a solasterid feeding on a pedinid urchin.

Alternatively directly “above” the Solaster in the image is an extremely spinose brittle star (oph in Fig. 23D ), possibly an ophiacanthid or an ophiotrichid, which might also represent a potential prey.

Occurrence: Esmerelda Bank , Marianas Island region, 447 m.

Images Examined

Esmerelda Bank , Marianas Island region, 15.02996792, 145.2229949, 447 m. EX1605 L1_IMG_20160508 T230745 Z_ ROVHD _ ASR _ AUD.jpg

Figures

FIGURE 23. Solaster spp. A. Solaster namake n. sp. orange form, in situ. Hawaiian Islands. B. Solaster sp. 1, Whole body in situ image. C. Close-up showing paxillae and other details. D Solaster sp. 2, Marianas Island region, 447 m. Urspine= pedinid urchin spines. Oph= ophiuroid.