Fromia heffernani (Livingstone, 1931)

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 : 13-15

Fromia heffernani (Livingstone, 1931)

FIGURE 5A–E

Ferdina Livingstone 1931: 306

Celerina A.M. Clark 1967: 193 ; Marsh 1977: 255; Jangoux 1978: 294; Guille & Jangoux 1978: 55; Oguro 1983: 221; Jangoux 1986: 128; George & George 1987: 245 (Table 8), 248; Marsh 1993: 55, 60; Rowe & Gates 1995: 80; Marsh 2000: 99 (Table 7); Lane et al. 2000: 473; Mooseleitner 2004: 245–247; Coleman 2007: 29, 30; Lane & Susetiano 2014: 55(Table 2)

Fromia Mah 2017: 8

Diagnosis

Body strongly stellate (R/r=3.5 to 6.3), arms narrow, elongate, triangular, interradial arcs acute ( Fig. 5A ). Abactinal plates abutted, more flattened proximally, becoming more strongly convex distally with some plates becoming nearly hemispherical distally. Granules form a continuous covering over abactinal, marginal, and actinal plate surface ( Fig. 5A–B ). Marginal plates 13–25 per side, 26 to 50 per interradius. Superomarginals and inferomarginals differ in size and morphology with inferomarginal plates more numerous and uniform than the superomarginal series. Superomarginal plates flat to weakly convex proximally and more strongly convex to nearly hemispherical distally especially in conjunction with distal abactinal plates developing further convexities distally ( Fig. 5B–C ). Actinal intermediate regions composed of a single plate series which terminates approximately 50–80% of the arm’s distance ( Fig. 5D ). Other than furrow spines, mostly 2 with minority showing 3, subambulacral spination is absent with granulation covering actinal surface up to base of furrow spines, obscuring adambulacral plate boundaries ( Fig. 5E ).

Comments

Fromia heffernani was originally described by A.M. Clark (1967) as the monotypic species within the genus Celerina , a species which was argued as having closer affinities to Ferdina like Ophidiasteridae based on the absence of subambulacral spines and a continuous cover of granules up to the base of the furrow spine. Molecular data ( Mah & Foltz 2011 b) showed Celerina as a synonym of Fromia and morphological evidence showed that while similar, the definition of this species was consistent with Fromia rather than the ferdinine goniasterids ( Mah 2018).

Fromia heffernani can variably display a color pattern similar to that of the widely occurring Fromia monilis (e.g. Coleman 2007), including a dark red disk and arm tips in addition to white arms and because of similar abactinal and marginal plate patterns, the two species are can be difficult to distinguish based on the abactinal surface. Marsh & Fromont (2020) outlined several character differences, but foremost among them the single row of furrow spines and the presence of granules up to the base of the furrow spines. Abactinal characters can be variable but the large convex tubercles on the distal abactinal arm surface can in some individuals be a useful distinction.

Although not as widespread as Fromia monilis , Fromia heffernani does occur throughout the central and to a lesser extent the South Pacific and the Indian Ocean. The species is varied with red and blue coloration on the disk and arms and a varied abactinal arm plate pattern (e.g. Coleman 2007; Marsh & Fromont 2020). Little is known regarding this species feeding habits or other aspects of biology.

Description of juvenile specimen (USNM E48992)

A very small specimen of Fromia heffernani , which demonstrates significant morphological differences from larger individuals, showing more uniform abactinal and marginal plates, further expression of incipient granules (=glassy granules).

Body stellate (R/r=3.6), arms triangular, interradial arcs acute. Abactinal, marginal and actinal plates with continuous granular cover.

Abactinal plates, flat, round to polygonal in shape extending onto arms where they become more elongate. Disk plates flat but variably one to five distinctly round concavities or bumps present on each arm. One concavity is always the largest of the three and in contact with superomarginals on either side of the arm. Other concavities are low and comparable in size to other plates on the disk. Where only one is present it is comparable in size to the other four. Each concavity with glassy tubercles, identical to those on marginal plates, largest with 20–25, smaller bumps with 10–15. These appear twice as large than the other ambient granules. Other surficial granules relatively small, approximately 20 counted along a 1.0 mm line. Madreporite with well-developed sulci, flanked by approximately four plates.

Marginal plates 10 per interradius (armtip to armtip). Marginals with more equivocal dimensions interradially but becoming more elongate along the arms. Surfaces are more strongly convex along the arms. Distalmost superomarginals in contact over midline. Superomarginals with glassy tubercles, 40 to 60 per plate in addition to the continuous granular cover. One interradius with a inferomarginal which is particularly convex relative to the other plates. Inferomarginals with 20–50 glassy tubercles, identical to the ones on the superomarginals.

Actinal surface covered by granules. Central plate on the actinal intermediate surface (adjacent to the oral plates) forms prominent bump in each interradius. There are additionally two to three strongly convex plates on actinal surface with 4 to 8 glassy tubercles.

Furrow spines 2 to 3, mostly 3, no subambulacrals but adjacent granules, 10–12 are more coarse than others on actinal surface (approximately twice the size) and more widely spaced.

Occurrence

Okinawa and southern Japan, 0–10, 46– 55 m.

Outside Japan. South China Sea, Malaysia, Rowley Shoals, Philippines, Papua New Guinea, Bali & Lembeh Strait, Sulawasi ( Indonesia), Great Barrier Reef, Queensland, Western Australia, Palau, Vanuatu, New Caledonia, Christmas Island, Maldives, 0– 58 m. (based on Mah 2018, Marsh & Fromont 2020).

Material Examined

USNM 45723 1 km WNW of Onna Village ( Horeshoe Cliffs ), Okinawa, Ryukyu Islands. 26.5 127.848, 55 m. coll. R. F. Bolland, 10 Nov 1984. 1 dry spec. R=1.1 r=0.3.

USNM E45991 , 1 km WNW of Onna Village ( Horeshoe Cliffs ), Okinawa, Ryukyu Islands. 26.5 127.848, 49 m. coll. R. F. Bolland, 30 July 1987. 1 dry spec. R=2.5 r=0.4

USNM E46051 1 km WNW of Onna Village ( Horeshoe Cliffs ), Okinawa, Ryukyu Islands . 26.5 127.848, 48.8 m. coll. R. F. Bolland, 22 Jan 1985. 1 dry spec. R=1.4 r=0.4.

USNM E48992 1 km WNW of Onna Village , Horseshoe Cliffs , Okinawa Island, Ryukyu Islands . 26.5, 127.848, 46 m. Coll. R.F. Bolland 17 March 1981. 1 wet spec. R=1.1 r=0.3.

Figures

FIGURE 5. Fromia heffernani USNM E45991 A. Abactinal surface. B. Abactinal-lateral view. C. Lateral view. D. Actinal surface. E. Oral region, actinal surface. Scale bar: A, D=3.0 mm; B–C, E=2.0 mm.