Microbrotula Gosline

M. Eric Anderson, 2005, Three new species of Microbrotula (Teleostei: Ophidiiformes: Bythitidae) from the Indo-West Pacific., Zootaxa 1006, pp. 33-42 : 34-35

Microbrotula Gosline , 1953

Microbrotula Gosline , 1953: 218 (type species: Microbrotula rubra Gosline , 1953, by original designation). Cohen and Wourms, 1976: 81 (new diagnosis). Cohen and Nielsen, 1978: 48 (diagnosis; mention of undescribed species). Nielsen and Cohen, 1999: 106 (diagnosis, key).

Included species. Microbrotula comprises five species, M. bentleyi sp. n., M. polyactis sp. n., M. queenslandica sp. n., M. randalli and M. rubra .

Diagnosis. The genus is distinguished from all other Bythitinae as defined by Cohen and Nielsen (1978) by the following combination of characters: Dwarf species reaching only 45 mm SL ( M. rubra ). Body relatively short, head length 25.7-29.2% SL. Vertebrae 11-13 + 33-44 = 44-56. Dorsal fin retrograde, its origin above vertebrae 7-11, anal-fin origin beneath vertebrae 14-17. Neural spines of vertebrae 4-8 depressed; spine of first vertebra much reduced. Eye small, 6.5-17.5% HL. Anterior nostril with slight tube, located just above upper lip. Rear portion of maxilla ensheathed in M. bentleyi and M. polyactis , free in remaining species, and with small, ventrally-directed projection at lower rear corner. Tongue with short, anterior projection, rounded at tip. Vomerine teeth in two small patches; palatine teeth viliform, in single row. Opercular spine strong, usually imbedded. Developed gill rakers 2-4, with tiny denticles on outer surface. Branchiostegal rays 7. Scales very small, imbricated, present on top of head and cheeks in adults. Lateral line mediolateral, of tiny papillae. Pectoral-fin rays 9-17, set on short peduncle that is higher than long. Pelvic fin of a single ray, its length growth-related but reaching almost to anus in adults. Caudal-fin rays 4-6 except in M. polyactis which has 7-8 rays. Male intromittent organ simple, without ossified or sclerified parts (pseudoclasper).

Key to the species of Microbrotula

1 Pectoral-fin rays 9-11 ................................................................................................... 2

- Pectoral-fin rays 13-17 ................................................................................................. 3

2 Five head pores at interorbital area; predorsal length 40.0-47.6% SL (dorsal-fin origin directly above vertebrae 10-11); prepelvic length 19.9-22.2% SL; distance symphysis of cleithra to pelvic fin insertion 10.7-14.8% HL; lateral scale rows 63-66; anal-fin rays 71-76; total vertebrae 52-56 ................................................................. M. randalli

- No head pores; predorsal length 34.6% SL (dorsal-fin origin above vertebra 7); prepelvic length 23.4-24.6% SL; distance symphysis of cleithra to pelvic fin insertion 26.2- 28.2% HL; lateral scale rows 56-57; anal-fin rays 62-64; total vertebrae 48-49 ......... ............................................................................................................ M. queenslandica

3 Pectoral-fin rays 13-14; caudal-fin rays 4-6; lateral scale rows 54-ca.60; orbit diameter6.5-13.9% HL ......................................................................................................... 4

- Pectoral-fin rays 16-17; caudal-fin rays 7-8; lateral scale rows 47-50; orbit diameter 16.0-18.7% HL ......................................................................................... M. polyactis

4 Vertebrae 11 + 40-41; dorsal-fin rays 81-92; anal-fin rays 72-80; predorsal length 43.5-47.6% SL; orbit diameter 6.5-9.1% HL; fleshy interorbital width 23.8-27.8% HL; lateral scale rows ca. 60 ........................................................................... M. rubra

- Vertebrae 11 + 33-35; dorsal-fin rays 65-71; anal-fin rays 55-59; predorsal length 36.5-41.3% SL; orbit diameter 10.9-13.9% HL; fleshy interorbital width 16.8-19.8% HL; lateral scale rows 54-55 ........................................................................ M. bentleyi