Microbrotula bentleyi, M. Eric Anderson, 2005

M. Eric Anderson, 2005, Three new species of Microbrotula (Teleostei: Ophidiiformes: Bythitidae) from the Indo-West Pacific., Zootaxa 1006, pp. 33-42 : 36-37

Microbrotula bentleyi sp. nov.

(Fig. 1)

Holotype. RUSI 65261 (female, 40.7 mm SL), South Africa, Aliwal Shoal at Eelskin , 30°15.0'S, 30°49.0'E, SCUBA coll., 25 m, sta. ACB 02-01 , 24 Jan. 2002, A. C. Bentley.

Paratypes (all Red Sea, Gulf of Aqaba ). USNM 227220 (male, 36.0 mm SL; female, 40.7 mm SL), bay at El Hamira , Egypt, SCUBA coll., 9-12 m, sta. VGS 69-23 , 09:45- 12:15 hr., 8 Sept. 1969, V. G. Springer and party. USNM 227226 (female, 29.2 mm SL; male, 33.4 mm SL), bay at El Hamira , Egypt, SCUBA coll., 0-16 m, sta. VGS 69-4 , 11:40-15:30 hr., 19 July 1969, V. G. Springer and party. BPBM 37875 (male, 37.3 mm SL), Ras Abu Galum , Egypt, SCUBA coll., 52-55 m, 2 Aug. 1976, J. E. Randall, O. Gon and R. Kurutz.

Diagnosis. A species of Microbrotula distinguished by the following combination of characters: vertebrae 11 + 33-35; pectoral-fin rays 14; lateral scale rows 54-55; dorsal-fin origin above vertebrae 7-8; anal-fin origin below vertebra 14; orbit diameter 10.9-13.9% HL; fleshy interorbital width 16.8-19.8% HL; predorsal length 36.5-41.3% SL.

Description. Counts and proportions, holotype first followed in parentheses by range of paratypes: Vertebrae 11 + 34 = 45 (11 + 33-35 = 44-46); dorsal-fin rays 70 (65-71); anal-fin rays 55 (55-59); caudal-fin rays 6 (6); pectoral-fin rays 14 (14); lateral scale rows 54 (54-55); horizontal scale rows, anal-fin origin to dorsal base 16 (16); developed gill rakers 3 (3); vomerine teeth 10 (4-16). Following proportions as percent SL: head length 29.2 (28.1-29.2); head width 14.3 (12.2-15.5); head depth 14.0 (14.0-16.3); predorsal length 37.6 (36.5-41.3); preanal length 51.6 (50.0-52.1); prepelvic length 24.6 (24.3- 26.7); body depth 15.0 (13.4-17.2); pectoral-fin length 14.7 (14.1-15.6); pelvic-fin length - (18.0-19.8 [8.1 in 29 mm SL juvenile]). Following proportions as percent HL: head width 48.7 (41.7-54.5); head depth 47.9 (47.9-57.9); prepelvic length 84.0 (83.9-95.1); orbit diameter 10.9 (10.9-13.9); snout length 18.1 (16.7-19.8); fleshy interorbital width 16.8 (16.8-19.8); body depth 51.2 (46.2-60.4); upper jaw length 45.0 (48.5-53.5); pectoral base depth 21.9 (15.6-18.8); pectoral-fin length 50.4 (48.5-53.2); pelvic-fin length - (52.8-68.2 [27.8 in 29 mm SL juvenile]); distance symphysis of cleithra to pelvic-fin insertion 33.6 (26.6-34.8).

Head moderately elongate, postorbital length almost four times snout length; nape and snout depressed. Head slightly deeper than wide at occiput. Tip of snout not projecting much beyond upper lip; low fleshy ridge at snout tip with weakly defined lobes under which lies row of sensory papillae. Upper jaw expanded posteriorly, ensheathed in long, fleshy pocket posteriorly; posteroventral corner with slight projection that is less developed in 29.2 mm SL juvenile than in adults. Teeth on jaws viliform, in 3-4 bands, with few caniniform teeth anteriorly in upper jaw and laterally in lower jaw. Caniniform vomerine teeth in two patches of 2-8 teeth, with 2-3 tiny teeth in each patch in largest specimens. Low, convoluted fleshy ridges on top of head, especially snout. Minute unpigmented sensory papillae on head in two irregular rows under eye and along upper jaw; uppermost courses behind eye and runs ventrally along anterior margin of preopercle; scattered papillae(not in rows) on snout (densest there) to nape; three irregular rows on lower jaw. No head pores. Tube of anterior nostril not well developed. Eye rounded, translucent orbital spectacle not reaching lens.

Body fully scaled including dorsal- and anal-fin bases, abdomen to posterior isthmus area and pectoral base, with three scale rows extending onto fin. Scales on head extend anteriorly on nape almost to interobital area, including cheeks and operculum.

Gill opening extending ventally to vertical through rear margin of upper jaw. Gill membranes united, free of isthmus posteriorly. Three developed gill rakers on lower limb of first arch; rakers slanted forward so rear margin oriented dorsally; row of minute denticles on rear margin. Pectoral fin on short peduncle; rays almost reach vertical through anus. At least one pelvic fin ray unbroken in four specimens, length growth-related (above). Pelvic-fin insertion on vertical slightly in advance of base of pectoral peduncle. Dorsal-fin origin above middle of pectoral rays; above vertebrae 7-8; anal-fin origin at mid-body, under vertebra 14. Male copulatory apparatus with fleshy hood elevated above abdomen immediately before anal-fin origin. Inner surface of anterior end of hood enclosing the simple, conical genital papilla, posterior to which is another, much smaller, median papilla.

Live coloration: Gulf of Aqaba specimen BPBM 37875 generally gray with brownish swathes on shoulder, dorsum and head; fins pink (from slide courtesy of J. E. Randall). South African specimen more uniformly light brown with light pink fins.

Etymology. Named in honor of Andrew Charles Bentley of Port Elizabeth, South Africa, now at the University of Kansas, USA, for his enthusiasm and help in the development of a program on western Indian Ocean fishes, and for collecting the holotype.

Distribution. Northeastern South Africa and Gulf of Aqaba, Red Sea, from near surface to 55 m in protected reef structures.

Remarks. This species appears closest to M. polyactis (below) in its morphometrics and most meristics, especially the low vertebral and unpaired fin ray counts, and the position of the unpaired fin origins. However, M. bentleyi differs from M. polyactis in its lower caudal-fin ray count (6 vs. 7-8), pectoral-fin ray count (14 vs. 16-17) and smaller scales (lateral scale rows 54-55 vs. 47-50.).