Sphaeriodiscus, Fisher, 1910

Mah, Christopher L., 2018, New genera, species and occurrence records of Goniasteridae (Asteroidea; Echinodermata) from the Indian Ocean, Zootaxa 4539 (1), pp. 1-116 : 85-86

Sphaeriodiscus sp. (small)

Comments. Based on granules, marginal plate shape and body form, this specimen was tentatively assigned to Sphaeriodiscus . Specimens examined herein and documented in other accounts (e.g., H.E.S. Clark and McKnight 2001; Fisher 1906) with characters that are consistently used to diagnose species display a general size range between approximately R=1.0 to 2.0 cm. The present individual might represent an ontogenetically early stage in which many features are not as yet clearly developed; it is included to suggest a range of morphology at least tentatively assigned to Sphaeriodiscus .

Description of specimen at R= 0.85 cm. Abactinal plates homogeneous in shape, many round to polygonal, and flattened but with much fewer granules per plate, 10–20 many of which have been abraded in the specimen. Marginal plates six, interradial plates quadrate, elongate, largest in size becoming smaller distally. Distalmost plates, esp. adjacent to terminal strongly convex. Actinal plates in two complete rows. Plate surface covered by 10– 15 round, coarse granules, approximately three along a 1.0 mm line. Furrow spines three to four, round in cross section. Subambulacrals two, each twice as thick as the furrow spine adjacent to it. Adambulacral plates with approximately five to eight granules per plate.

Color in life was white.

Material Examined. IE-2013-17269 , Western Indian Ocean , 11°30’S 47°29’E, 694–733 m. Coll. S. Samadi, BIOMAGLO DW 4814 , 25 Jan 2017. 1 wet spec. R=0.85 r=0.7