Fromia balansae Perrier 1875

Mah, Christopher L., Kogure, Yoichi, Fujita, Toshihiko & Higashiji, Takuo, 2024, New Taxa and Occurrences of Mesophotic and Deep-sea Goniasteridae (Valvatida, Asteroidea) from Okinawa and adjacent regions, Zootaxa 5403 (1), pp. 1-41 : 9-11

Fromia balansae Perrier 1875

FIGURE 3A–D

Perrier 1875: 178; Koehler 1910: 140; A.H. Clark 1952: 285; Tortonese 1955: 677; Clark & Rowe 1971: 34, 63.

Diagnosis

Body stellate, arms broad based, tapering, R/r approximately 3.5–3.6 ( Fig. 3A ). Abactinal side convex. Abactinal plates approximately five plates across width between the superomarginals on the proximal half of the arm ( Fig. 3B ). Carinal plates distinct, especially on small-sized individuals (R=0.7– 0.7 cm) with plates, slightly enlarged relative to the adradial plates ( Fig. 3B ). Abactinal granulation even. Distal granules on superomarginal plates relatively homogeneous.

Comments

Small sized individuals (R= 0.6–0.7 cm) displayed a particularly prominent series of carinal plates with each plate slightly enlarged relative to the adradial abactinal plate ( Fig. 3A–B ). There is close similarity to several other species of Fromia with relatively minor differences. Fromia balansae differs from Fromia milleporella based on a relatively flat abactinal surface and indistinct carinal plates in the latter and a convex abactinal surface with a distinct carinal plate series in the former. Fromia balansae and Fromia hemiopla differ based on the overall size of distalmost superomarginal granules with those in the former identified as “evenly fine” or presumably homogeneously sized, small granules versus those in Fromia hemiopla with distalmost superomarginal granules bearing enlarged central granules or tubercles. Distinctions herein were based on these enlarged central granules in Fromia hemiopla as 2X to 3X the size of adjacent granules, whereas those in F. balansae were only 1 to at most 2X the size of adjacent granules ( Fig. 3B ). Further phylogenetic tests using molecular data for these species is desirable.

Occurrence

Southern Japan, 55 m. (new occurrence)

Outside Japan. Mauritius, New Caledonia, Marshall Islands, Samoa, 18– 22 m. (new occurrence)

Material Examined

USNM E 50773 1 km WNW of Onna Village , Okinawa, Ryukyu Islands, Japan, 26.5, 127.848, 55 m. Coll. R.F. Bolland, 3 Sept. 1984. 2 wet specs. R=0.7 r=0.2, R=0.6 r=0.2.

USNM 1145356 Halfway between Albion Fisheries Research Centre and Point Aux Caves , Bare de la Petite Riviere, West coast Mauritius, Indian Ocean . 18–22 m. Coll. P. Heemstra, et al. 1 dry spec. R=2.2 r=0.6.

Figures

FIGURE 3. Fromia balansae USNM E50773 A. Abactinal surface. B. Strongly convex abactinal plates. C. Actinal surface. D. Closeup oral region, actinal surface. Scale bar: A, C=1.0 mm; B, D=0.5 mm.