Microbrotula queenslandica, 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 : 40-41

Microbrotula queenslandica sp. n.

(Fig. 3)

Holotype. AMS I.20206-019 (female, 29.5 mm SL), Australia, Great Barrier Reef, One Tree Island , 23°30'S, 152°05'E, scuba in 22-30 m, Frank Talbot and party, 3 Dec. 1969.

Paratype. AMS I.20206-041 (male, 31.2 mm SL), same collection as holotype.

Diagnosis. A species of Microbrotula distinguished by the following combination of characters: vertebrae 12 + 36-37 = 48-49; pectoral-fin rays 11; lateral scale rows 56-57; dorsal-fin origin above vertebra 7; anal-fin origin below vertebrae 15-16; orbit diameter 12.2-13.1% HL; fleshy interorbital width 15.2-16.1% HL; predorsal length 34.6% SL.

Description. Counts and proportions, holotype first followed in parentheses by paratype. Vertebrae 12 + 37 (12 + 36); dorsal-fin rays 80 (80); anal-fin rays 62 (64); caudal-fin rays 6 (6); pectoral-fin rays 11 (11); lateral scale rows 56 (57); horizontal scale rows, anal-fin origin to dorsal base 15 (15); developed gill rakers 3 (3); vomerine teeth 7 (4). Following proportions as percent SL: head length 27.8 (27.9); head width 12.5 (13.1); head depth 13.6 (13.3); predorsal length 34.6 (34.6); preanal length 46.1 (53.2); prepelvic length 24.6 (23.4); body depth 13.9 (13.5); pectoral-fin length 9.8 (11.5); pelvic-fin length 14.2 (15.1). Following proportions aas percent HL: head width 45.1 (47.1); head depth 48.8 (47.7); prepelvic length 88.4 (83.9); orbit diameter 12.2 (13.1); snout length 19.5 (20.1); fleshy interobital width 15.2-16.1; body depth 50.0 (48.3); upper jaw length 50.6 (50.6); pectoral base depth 16.5 (16.1); pectoral-fin length 35.4 (41.4); pelvic-fin length 51.2 (54.0); distance symphysis of cleithra to pelvic-fin insertion 26.2 (28.2).

Head ovoid, postorbital length 3.4-3.5 times snout length; nape and snout depressed. Head very slightly deeper then wide at occiput. Tip of snout fleshy, projecting beyond upper lip, with four weak lobes under which lies short row of sensory papillae. Upper jaw expanded posteriorly, shallowly ensheathed in fleshy pocket running almost the length of the jaw; posteroventral corner with slight projection. Teeth in jaws viliform, in four bands anteriorly in upper jaw, three in lower, with short row of lateral canine teeth in lower jaw and group of three canines in upper jaw at symphysis in both specimens. Caniniform vomerine teeth in two patches of 3 + 4 teeth in holotype and 2 + 2 teeth in paratype. Low fleshy ridges on head above, below and behind eyes; snout ridges weakly developed in these subadults. Minute unpigmented sensory papillae on head in row under eye and scattered on snout, preorbital and interorbital areas; three irregular rows on lower jaw. No head pores. Tube of anterior nostril weak. Eye round, translucent orbital spectacle not reaching lens.

Body fully scaled; no scales on dorsal- and anal-fin bases in these subadults. Scales present on abdomen to posterior isthmus area and pectoral base, with a single scale row extending onto fin. Scales on head extending anteriorly only to nape. Small patch of scales on cheeks, none yet developed on operculum.

Gill opening extending ventrally to vertical just in front of 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; two rows of minute denticles on rear margin; five denticulated raker plates below developed ones. Pectoral fin on short peducle, middle rays longest, almost reaching vertical through anus. Pelvic-fin insertion on vertical through posterior third of opercle. Dorsal-fin origin above middle of pectoral fin, above vertebra 7; anal-fin origin slightly in advance of mid-body, under vertebrae 15-16. Male copulatory organ as in M. polyactis , with low, fleshy hood before anal-fin origin and simple, elongate genital papilla anteriorly followed posteriorly by pair of much smaller papillae; no discernible lobe at tip of genital papilla.

Live coloration unknown, uniformly straw-colored in preservative. Eye blue.

Etymology. Named after the Australian state of Queensland where the types were collected(Great Barrier Reef).

Distribution. A single collection from coral reef habitat at One Tree Island, Capricorn Group.

Remarks. This species appears close to M. randalli in most meristics, especially the more numerous precaudal vertebrae and few pectoral-fin rays. However, M. randalli is quite distinct from all other congeners, as discussed below.

Discussion

The pelvic-fin insertion in the three new species is more retrograde than in M. randalli and M. rubra , with the insertion under the base of the pectoral peduncle or slightly in advance of it in the new species and farther forward in M. randalli and M. rubra (distance cleithral symphysis to pelvic insertion 10.7-14.8% HL in M. randalli [not studied in M. rubra , but see Gosline, 1953, fig. 1c] vs. 26.2-34.8% HL in the three new species). The three new species differ from M. rubra in their larger eyes (orbit diameter 10.9-18.7% HL in the new species vs. 6.5-9.1% HL in M. rubra ) and narrower fleshy interorbital width (width 15.2- 24.4% HL in the new species vs. 23.8-27.8% HL in M. rubra ). Microbrotula randalli chiefly differs from all four of its congeners in its five head pores, high vertebral counts (52-56 vs. 44-49 in the new species, 51-52 in M. rubra ), low pectoral ray count (9-11 vs. 11-17 in congeners), smaller scales (lateral scale rows 63-67 vs. 47-57 in the new species, ca. 60 in M. rubra ), and shorter prepelvic distance (19.9-22.2% SL vs. 20.9-26.7% SL in congeners).