Mycteroperca GILL, 1863

Heemstra, P. C., 1991, A Taxonomic Revision Of The Eastern Atlantic Groupers (Pisces: Serranidae), Bol. Mus. Mun. Funchal 43 (226), pp. 5-71 : 46-48

Genus Mycteroperca GILL, 1863

Mycteroperca GILL, 1863: 236 (type-species, Serranus olfax JENYNS, 1843 by subsequent designation of GILL, 1865: 105).

Trisotropis GILL, 1865: 104 (type-species, Johnius guttatus BLOCH & SCHNEIDER, 1801 [= Mycteroperca venenosa ], by original designation).

Parepinephelus BLEEKER, 1876: 257 (type-species, Serranus acutirostris VALENCIENNES , [= Mycteroperca acutirostris ] by monotypy).

Archoperca Jordan & EVERMANN, 1896: 1171 (type-species, Mycteroperca boulengeri JORDAN & STARKS [= Myctemperca xenarcha ] by monotypy).

Xystmperca JORDAN & EVERMANN, 1896: 1169 (type-species, Mycteroperca pardalis GILBERT [= Mycteroperca rosacea ] by monotypy).

Diagnosis: Body oblong, the depth less than head length and contained 2.7- 3.6 times in standard length; head length 2.5 -3.0 times in SL. Dorsal head profile evenly convex; snout dlstinctly longer than eye diameter (except in fish less than 10 cm SL); interorbital convex, the width greater than eye diameter in fish more than 20 cm. SL; preorbital depth more than half eye diameter (except fish less than 15 cm SL), 8- 13 times in head length; preopercle finely serrate, the serrae at corner enlarged or not; upper edge of operculum convex; rear nostrils equal to or distinctly larger than anteriors. Caudal fin usually truncate or distinctly concave, with 8 + 7 branched rays and 9- 12 + 9- 12 procurrent rays. Dorsal fin with 11 spines and 15 - 18 rays, the base of the soft-rayed part shorter than base of spinous part; anal fin with 3 spines and 10- 13 rays, the fin margin of adults angular or pointed; paired fins subequal; pectoral fins rounded, with 15- 18 rays, the middle rays longest. Midlateral body scales ctenoid. Lower jaw projecting in front of upper jaw; well-developed canines at front of jaws; teeth present on palatines; distal part of ventral edge of maxilla straight, no knob, distinct step or hook; supramaxilla well developed. Su~ praneural bones 2, the second one distinctly smaller than the first; no triseginental pterygiophores supporting dorsal or anal fin rays; epipleural ribs on first lovertebrae. Cranial crests well developed, the frontoparietal crests parallel, joining supraorbital ridge; anterior ends of frontals contiguous, meeting transverse wall of supraethmoid; supraoccipital crest not carried forward onto frontals; interorbital width greater than vomer width; parasphenoid straight.

GEOGRAPHICAL DISTRIBUTION

Tropical and subtropical waters of the Atlantic and eastern Pacific oceans. In the eastern Atlantic, the genus is represented by two species: M. rubra , known from the Mediterranean to the Bay of Biscay and along the west coast of Africa south to Angola, and M. fusca which occurs at Madeira, the Azores, and the Canary and Cape Verde Islands.

REMARKS

Adults occur on coral reefs and rocky bottoms in depths of 20-200 m.; juveniles occur in shallow water on rocky bottoms, seagrass beds, and in estuaries. The genus comprises 15 species: 2 in the eastern Atlantic, 8 in the western Atlantic and 5 in the eastern Pacific.

The genus Mycteroperca appears to be closely related to Epinephelus . Species of both genera have 11 dorsal fin spines and lack the trisegmental pterygiophores in the dorsal and anal fins and the terminal knob on the lower corner of the maxilla that are characteristic of species of Cephalopholis .

M. fusca , M. rubra and M. acutirostris ( VALENCIENNES, 1828) are three allopatric sibling species that comprise the Mycteroperca rubra species complex. These species can be distinguished by the following key:

1 a. Total gill-rakers 48-55; maxilla width 4.4-5.8% SL (for fish 10-34 cm. SL); (western Atlantic) M. acutirostris

Ib. Total gill-rakers 32-49; maxilla width 3.8-5.2% SL (for fish 13-55 cm. SL); (eastern Atlantic) 2

2 a. Lower-limb gill-rakers 28-31 M. rubra

2b. Lower-limb gill-rakers 20-24 M. fusca

M. acutirostris has generally been known as M. rubra and thought to be a single species that occurs on both sides of the Atlantic Ocean. Although SMITH (1971) synonymized nominal species from the eastern and western Atlantic under the name of M. rubra and gave the distribution as both sides of the Atlantic plus the Mediterranean, he did not examine any specimens from the eastern Atlantic. I compared 20 specimens, 10-34 cm. SL, of M. acutirostris from the western Atlantic with 34 specimens, 6 -59 cm., from the eastern Atlantic and Mediterranean. These 34 specimens (which are here identified as M. rubra ) have fewer gill-rakers (lower-limb rakers = 28-31, versus 32-36 in acutirostris ) and a narrower maxilla (greatest width 3.8-4.4% SL, for 14 fish 13 -45 cm. SL, versus 4.458% SL, for 13 acutirostris of 10-34 cm. SL). These differences between M. rubra and acutirostris are relatively minor, and in view of the allopatric distributions of these two taxa, they might be considered as only subspecifically distinct. But the presence of a third distinct population ( M.fusca ) that occurs at the Azores, Madeira, Canaries and Cape Verde Islands in the Eastern Atlantic implies that each of these populations is genetically distinct from the other two.