Synchiropus (Acommissura), Fricke, 2016

Fricke, Ronald, 2016, Synchiropus novaehiberniensis, a new species of dragonet from New Ireland, Papua New Guinea, western Pacific Ocean, with a review of subgenus Synchiropus (Neosynchiropus) and description of a new subgenus (Teleostei: Callionymidae), Journal of Natural History 50, pp. 3003-3028 : 3011-3012

Acommissura subgen. nov. [subgenus of Synchiropus Gill ]

Type species: Synchiropus sechellensis Regan, 1908 . Gender: Neuter.

Neosynchiropus Nakabo, 1982: 92 (part).

Synchiropus-ocellatus species-group: Fricke 1983a: 586 (part).

Synchiropus (subgen. 1): Fricke 2002: 102 (part).

Diagnosis

A subgenus of the genus Synchiropus with a small branchial opening in sublateral position; head short (2.8–5.0 in SL); eye moderate to large (1.8–3.9 in head length); preopercular spine with a short, usually upcurved main tip, one to three curved points on its dorsal margin, occasionally an antrorse spine at its base, ventral margin smooth, slightly concave; supraorbital tentacle present in some species; no transverse lateral-line commissure on dorsal side of caudal peduncle; first dorsal fin with four flexible spines, in the male usually much higher than second dorsal fin, in the female slightly higher to lower than second dorsal fin; second dorsal fin distally straight, with eight branched rays (last divided at base); anal fin with seven unbranched rays (last divided at base, the anterior tip bifurcate); 18–23 pectoral-fin rays; caudal fin distally rounded, the seven median rays branched; cranium moderately depressed; lateral ethmoid not strongly depressed; supraethmoid with a large foramen in the centre; supraoccipital bearing a low crest; pterosphenoid with an inward projection towards the brain cavity; nasal bones present; upper jaw protracted ventrally; anterior tip of premaxillary pointed; lower jaw moderately depressed; sesamoid articulars slightly curved; urohyal with the middle ramus longer than the ventral ramus, and anterior dorsal edge of middle ramus spoon-shaped; third branchiostegal ray attached to abaxial face of epihyal; soft retrorse spine at posterodorsal end of opercle not filamentous; post-temporal notch opening horizontally; anteroventral ramus of cleithrum narrow; coracoid without a process at its dorsal margin; vertebrae 7 + 14; second neural spine slender, sharply pointed.

Etymology

A (Latin) meaning without; commissura (Latin) meaning commissure. The name refers to the missing lateral line commissure across the dorsal side of the caudal peduncle. The gender of Acommissura is neuter.

Comparisons

The subgenus Synchiropus (Acommissura) mainly differs from Synchiropus (Neosynchiropus) by the unbranched anal-fin rays [branched in Synchiropus (Neosynchiropus) ], and from the other subgenera of the genus by the absence of a transverse lateral-line commissure on the dorsal side of the caudal peduncle.

Remarks

A revised checklist of the species assigned to the subgenera Synchiropus (Neosynchiropus) and Synchiropus (Acommissura) subgen. nov. is presented below, as well as a key to the species. The subgenus Acommissura comprises five species (distribution of these species see Figure 7 ).

Checklist of the species included in the subgenus Synchiropus (Acommissura) subgen. nov.

Figures

Figure 7. Distribution of the subgenus Synchiropus (Acommissura) subgen. nov. in the Indo-West Pacific. 1 Synchiropus ijimai. 2 Synchiropus morrisoni. 3 Synchiropus novaehiberniensis sp. nov. 4 Synchiropus sechellensis. 5 Synchiropus tudorjonesi.