Family Trichiuridae 474cutlassfishes Marine Atlantic Indian and Pacific

Body very elongate and strongly compressed; protruding lower jaw; teeth very long; maxilla concealed by preorbitals; fanglike teeth usually present; single nostril on each side; gill cover splintered; dorsal fin extremely long based, with spines and soft rays (spinous portion usually shorter than soft rayed portion, notch between two portions in some species); anal fin with two spines and 56-121 soft rays; caudal fin small or absent; pectoral fin low on body; pelvic fin reduced (with a scalelike spine and one rudimentary soft ray) or absent; vertebrae 98-192 (34-53 + 55-151).

Ten genera with 39 species (e.g., Nelson, 1994; Parin, 1995; I. Nakamura and N. V. Parin in Carpenter and Niem, 2001).

Subfamily Aphanopodinae. Caudal fin small, forked; pelvic fin present, with scalelike spine and one rudimentary soft ray (external fin may be present only in juvenile); spinous dorsal fin with 38-46 rays, slight notch at division of spinous and soft portions.

Two genera, Aphanopus and Benthodesmus, with 18 species (e.g., Parin, 1995).

Subfamily Lepidopodinae. Caudal fin present (small and forked) or absent; pelvic fin present, rudimentary; spinous dorsal fin usually with 3-10 rays, spinous and soft portions continuous; lateral line descending gradually behind the pectoral fin.

Five genera, Assurger, Eupleurogrammus, Evoxymetopon, Lepidopus, and Tentoriceps, with about 18 species.

Subfamily Trichiurinae (Hairtails). Caudal fin and hypurals absent; pelvic fin and skeleton absent; spinous dorsal fin with three or four rays, spin-ous and soft portions continuous; lateral line descending steeply from the pectorals and running near ventral profile of body.

Three monotypic genera, Demissolinea, Lepturacanthus, and Trichiurus (e.g., Burhanuddin and Iwatsuki, 2003).

Family SCOMBRIDAE (475)—mackerels and tunas. Marine (rarely freshwater); tropical and subtropical seas.

Two dorsal fins (depressible into grooves) with 5-12 finlets behind second dorsal and anal fins; first dorsal fin with 9-27 rays, origin well behind head;

Scombridae

pectoral fins inserted high on body; pelvic fins with six rays, placed beneath the pectorals; gill membranes free from isthmus; scales cycloid and usually small; slender caudal peduncle with two keels; specialized subcutaneous vascular system in Thunnus and its close relatives; vertebrae 31-64.

Some members are endothermic (see under suborder Scombroidei). These fast-swimming fish constitute popular sport and valuable commercial fisheries. Length up to 4.2 m, attained by Thunnus thynnus.

Fifteen genera with 51 species (about half the species belong to Scomberomorus and Thunnus) (e.g., Collette et al., 2001; Collette, 2003c,d). The following classification is based on Collette et al. (2001). An immense literature exists on this subfamily with B. B. Collette giving us our present understanding of the diversity and systematics of this commercially important group.

Subfamily Gasterochismatinae. Scales moderate in size, about 80 in lateral series; pelvic fins longer than head length in juveniles, fitting into a deep ventral groove.

One species, the aberrant Gasterochisma melampus, primarily of the Southern Ocean.

Subfamily Scombrinae. Scales minute or absent.

tribe scombrini (mackerels). Two genera, Rastrelliger and Scomber, with seven species. As with many common names, the name "mackerel" is used for species in many different families (e.g., Nelson et al., 2004).

tribe scomberomorini (spanish mackerels). Three genera, Acanthocybium, Grammatorrcynus, and Scomberomorus, with 21 species. S. sinensis, although normally marine, occurs in estuaries and is known from 300 km up the Mekong River.

tribe sardini (bonitos). Four genera, Cybiosarda,, Gymnosarda, Orcynopsis, and Sarda, with seven species.

tribe thunnini (tunas). Five genera, Allothunnus, Auxis, Euthynnus, Katsuwonus, and Thunnus, with 15 species.

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