Scorpaenopsis rubrimarginatus, Fricke & Durville & Mulochau, 2013

Fricke, Ronald, Durville, Patrick & Mulochau, Thierry, 2013, Scorpaenopsis rubrimarginatus, a new species of scorpionfish from Réunion, southwestern Indian Ocean (Teleostei: Scorpaenidae), Cybium 37 (3), pp. 207-215 : 208-212

Scorpaenopsis rubrimarginatus new species

( Figs 1 -4)

Holotype

MNHN 2012-0401 (24.3 mm SL, male), off Saint-Gilles , La Réunion, 21°03’23’’S- 55°13’04’’E, 80 m depth, P. Durville, 2011.

Diagnosis

The following combination of characters distinguishes Scorpaenopsis rubrimarginatus from small and short-snouted species with the nape and anterior body not highly arched, and with the upper opercular spine divided into two or more points (two points in S. rubrimarginatus ): 16 pectoral-fin rays, 23 lateral-line scales, 42 scales in longitudinal series on body, the posterior lacrimal spine single, a broad space present between the eye and the suborbital ridge, the suborbital ridge bearing five retrorse spines, the interorbital ridges not elevated posteriorly to join the tip of the tympanic spines, a deep subtriangular suborbital pit present, the base of the parietal spines curving strongly into the occipital pit, the orbit large (eye diameter 0.62 in snout length/preorbital length, 2.4 in head length), a small, triangular supraocular tentacle present, the head length 2.3 in SL, the first dorsal-fin spine 2.5 in second spine, the second anal-fin spine about equal in length to third spine, and the pectoral-fin of the male longest, its length 2.1 in head length. Penultimate dorsal-fin spine 2.2 in last spine. Second anal-fin spine short, 3.2 in head. First anal-fin spine 1.4 in length of second spine (73% of that length), and 2.2 in length of third spine (46% of that length). Uppermost and lower eight rays of pectoral fin unbranched, remaining rays branched; eighth ray longest, its length less than head length; lower unbranched rays slightly thickened; posterior margin of fin rounded.

Colour in preservative

Body pale yellowish, dorsal parts of head, opercle, and anterior dorsal parts of body with dark brown pigment ( Fig. 1 ). Eye dark grey, dorsally with dark brown pigment. Fins pale whitish, except a large black spot basally on 8 th- 10 th pectoral fin rays; pectoral fin with few additional small black pigment spots.

Colour in life

Body pale yellowish, dorsal parts of head, opercle, and anterior dorsal parts of body with oblique, brownish yellow to rose grey bars (Fig. 4; the presumed female colouration is based on photographed specimens, which were not collected). Eye brownish yellow to rose grey, dorsally with crimson blotches and streaks. Dorsal fin pale whitish to yellow, with broad, crimson bars. Anal fin bright crimson, distal part of posterior membranes bluish white. Caudal fin pale whitish to yellow, with a basal and a distal vertical crimson bar. Pectoral fins pale whitish to brownish yellow, basal two-thirds with brownish to rose-grey blotches, a broad distal margin bright crimson, leaving the tips of the fin-rays bluish white. Male with a large black spot basally on 8 th- 10 th pectoral fin rays; this spot, which is found on both pectoral fins of the holotype and was observed on additional photographed specimens, is missing in the presumed females. Pelvic fins bright crimson.

Distribution

This species is only known from the holotype, which was collected at 80 m depth off Saint-Gilles , Réunion, Mascarene Islands, southwestern Indian Ocean .

Etymology

Ruber (Latin) = red; marginatus (Latin) = margined. The name of the new species refers to the conspicuous red margin of the pectoral fin.

Comparison

This new species is a member of the lineage of small, short-snouted species like Scorpaenopsis cotticeps with the upper opercular spine divided into two or more points, as defined by Randall and Poss in Randall and Eschmeyer (2001). Within this lineage (key couplet no. 7 in the key to the genus presented below), it differs from S. brevifrons , S. crenulata , S, pluralis , S. vittapinna in its single posterior lacrimal spine (2-3 points in those species) and the large orbit (0.62 in snout length/preorbital length, compared to 1.2-1.7 in those species). From the Hawaiian Islands endemic Scorpaenopsis altirostris , the new species differs in the second anal-fin spine which is about equal in length to the third spine (clearly longer than third spine in S. altirostris ), possibly the larger eye (eye diameter 2.4 in head length, compared to 3.3-3.6 in S. altirostris ; however, the eye may be relatively larger in the small holotype of S. rubrimarginatus n. sp.), the shorter head (head length 2.3 in SL, compared with 1.9- 2.0 in S. altirostris ), its 16 pectoral-fin rays (usually 18 in S. altirostris ), and its 42 longitudinal scale series (45 in S. altirostris ). It is distinguished from the South African species S. gilchristi by the broad space between the suborbital ridge and the eye (suborbital ridge directly below the eye in S. gilchristi ), the presence of a deep subtriangular suborbital pit (suborbital pit usually absent in S. gilchristi ), the small and triangular supraocular tentacle (long, fimbriate, longer than eye diameter in S. gilchristi ), the mandibular pore pattern (pores at symphysis of lower jaw open medially to a deep midventral pit in S. gilchristi ), and the slightly higher lateral-line scale count (22 in S. gilchristi ); the holotypes of the two species are directly compared in table II. Scorpaenopsis rubrimarginatus n. sp. differs from S. cotticeps in its 42 longitudinal scale series (33-37 in S. cotticeps ), the interorbital ridges which are not elevated posteriorly to join the tip of the tympanic spines (elevated and joining the tympanic spines in S. cotticeps ), and the base of the parietal spines curving strongly into the occipital pit (not curving into occipital pit in S. cotticeps ). The new species is distinguished from the Marquesas Islands endemic S. pusilla in its suborbital ridge bearing five retrorse spines (four spines in S. pusilla ), the absence of a supraocular tentacle (large supraorbital tentacle present in S. pusilla ), the first dorsal-fin spine 2.5 in second spine (1.85 in S. pusilla ), and the pectoral-fin with a small black blotch basally on 8 th- 10 th rays (lacking such a black blotch in S. pusilla ).

The new species differs from Scorpaenopsis longispina , which also occurs at the Mascarenes and may have a red colour pattern, in its smaller body size ( S. longispina reaching 92 mm SL), in having the upper opercular spine divided into two points (single in S. longispina ), in its 42 scales in the longitudinal series on the body (49-53 in S. longispina ), the body depth 2.8 in SL (2.95-3.2 in SL in S. longispina ), the first dorsal-fin spine 2.5 in length of second spine (1.95-2.15 in S. longispina ), the second dorsal fin in the male pale in preservative, with a broad red bar in life, but without basal dark spots (with two basal dark spots in S. longispina ), and the male’s pectoral-fin with a single characteristic centralbasal black spot (with several irregular dark spots in lower half).

A revised key to scorpaenid fish species of the genus Scorpaenopsis is presented below to distinguish Scorpaenopsis rubrimarginatus n. sp. from other species of the genus.

Remarks

The Scorpaenopsis cotticeps lineage, which comprises small and short-snouted species with the upper opercular spine divided into two or more points, now includes nine species, mostly from shallow to very deep water in isolated, marginal Indo-Pacific localities. Other species have restricted distribution ranges in northeastern South Africa, Wallis and Futuna, the Hawaiian Islands and the Marquesas Islands, while a single species is widespread in shallow water (2.5- 28 m) from East Africa to the Society Islands ( Scorpaenopsis vittapinna ). The Wallis and Futuna endemic Scorpaenopsis crenulata has been collected at a depth of 600 m. Together with the Hawaiian Islands endemics S. altirostris (79-134 m depth) and S. pluralis (110 m depth), the new species S. rubrimarginatus n. sp. (80 m depth) is intermediate between S. crenulata and the other species known in the group (which are known from 1-50 m depth).

A male and a presumed female of the new species were photographed on black sand (Fig. 4); the species is expected to be associated with deep volcanic rock habitats. It is difficult to collect in such habitats which are below regular SCUBA-diving depths and barely accessible by dredges or trawls.

Figures

Figure 1. - Scorpaenopsis rubrimarginatus new species, holotype, MNHN 2012-0401 (24.3 mm SL), lateral view, colouration in preservative. Figure 2. - Scorpaenopsis rubrimarginatus new species, holotype, MNHN 2012-0401 (24.3 mm SL), dorsal view of head. Figure 3. - Scorpaenopsis rubrimarginatus new species, holotype, MNHN 2012-0401 (24.3 mm SL), ventral view of head. Figure 4. - Scorpaenopsis rubrimarginatus new species, male (right) and presumed female (left); underwater photograph, off Saint-Gilles, Réunion, 80 m depth (photograph: P. Durville).