Fromia labeosa Arai and Fujita 2021

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 : 17-19

Fromia labeosa Arai and Fujita 2021

FIGURE 7A–F

Fromia sp. Arai et al. 2018: 194, 196.

Fromia labeosa Arai and Fujita 2021: 13 .

Diagnosis

Body stellate (R/r=3.6–4.1), arms slender, disk small. Abactinal plates flat, polygonal in shape, abutted. Abactinal, marginal plates covered by continuous granules that obscure plate boundaries ( Fig. 7A–B ). Marginal plates quadrate, uniform, gradually decreasing in size along arm ( Fig. 7C ). Large elliptical pedicellariae present on the actinal surface at oblique angle to the adambulacral plates ( Fig. 7D–F ). Furrow spines, 2 to 4, mostly 3; subambulacral spines thick, short, approximately 50% the height of the furrow spines ( Fig. 7E–F ). Adambulacral plates with granules, 2–4 identical with those on actinal plate surface.

Comments

These specimens agree with the original description in nearly all respects except for the abundance and location of the pedicellariae. The specimen herein shows pedicellariae which are positioned at more oblique angles ( Figs. 7E– F ) to the tube foot groove compared to the holotype figured by Arai and Fujita (2021) in which the pedicellariae are oriented at perpendicular or transverse angles relative to the tube foot groove. The relative size of the pedicellariae on USNM 1659486 is approximately equivalent to or greater than the width of two adambulacral plates, whereas the Ogasawara specimen shows pedicellariae which are approximately the width of a single adambulacral plate. The pedicellariae themselves also differ in morphology, with some displaying four granular valves and strong curves and perpendicular bends in contrast with the straight pedicellariae shown by Arai and Fujita (2021). Large pedicellariae extend from the proximal arm but are absent at approximately 75% of the arm distance in USNM E48903.

This is the first recorded occurrence of this species beyond the Ogasawara Islands and in shallower depths, 52–70 m. Original depth occurrence was from 56–137 m depth.

Occurrence

Okinawa, Ogasawara Islands, 52 –137 m.

Not known outside of Japanese waters.

Material Examined

USNM E48903 1 km WNW of Onna village , Horseshoe Cliffs , Okinawa, Ryukyu Islands. 26.5 127.848, 70.0 m. Coll. R.F. Bolland 16 Aug 1981. 1 wet spec. R=2.0 r=0.5.

USNM 1659486 3km WNW of Yuhi Misaki, Okinawa, Ryukyu Islands, Japan. 26.8467, 127.533, 52–55 m. Coll. R.F. Bolland, 14 Nov. 1987. 1 wet spec. R=3.3 r=0.8.

Figures

FIGURE 7. Fromia labeosa USNM 1659486 A. Abactinal surface. Scale=3.0 mm. B. Abactinal surface detail. C. Lateral view. D. Actinal surface. E. Actinal surface showing pedicellariae. F. Actinal pedicellariae. Scale bar: A, D=3.0 mm; B–C=2.0 mm; E=1.0 mm; F=0.5 mm.