Two new deep-water species of the genus Thorogobius (Teleostei: Gobiidae) from the upper continental slope of the Eastern Central Atlantic.

Abstract

Two new gobiid species, Thorogobius alvheimi sp. nov. and Thorogobius laureatus sp. nov. (Teleostei: Gobiiformes: Gobiidae), are described from the outer continental shelf and upper slope of the Eastern Central Atlantic off Angola, Ghana and São Tomé and Príncipe. The specimens were trawled from depths between 57 and 208m. The new species are most similar to Thorogobius angolensis. Thorogobius alvheimi sp. nov. is distinguished from its congeners in the combination of following characters. Fins: first dorsal fin with the second and third spines distinctly elongated; pectoral fin ray count 20-21; pelvic disc complete and short with well-developed anterior membrane (frenum) and pointed lateral lobes. Scales: nape and predorsal area naked; no scales on opercle; scales in longitudinal series 27-31. Pattern of free neuromasts: supratemporal rows tr and trp developed, extending transversally between pores H and K; longitudinal row g short, not passing row m posteriorly and distinctly distant from row h; infraorbital row 6 long, ventrally extending to lower margin of preopercle, its ventral section 6i originating anterior to its dorsal section 6s; posterior lateral row h reaching anteriorly above posterior third of opercle. Coloration: body uniformly pale fawn and brown; margin of scale pockets dark brown pigmented, yielding a reticulated pattern; pale spots on nape and predorsal area; caudal fin uniformly dusky greyish. Thorogobius laureatus sp. nov. is distinguished from its congeners in the combination of following characters. Fins: first dorsal fin the second and third spines distinctly elongated; pectoral fin ray count 19-22; pelvic disc complete, short, with well-developed anterior membrane (frenum) with pointed lateral lobes. Scales: scales on sides of predorsal area and midline mostly naked; no scales on opercle; scales in longitudinal series 24-27. Pattern of free neuromasts (sensory papillae): supratemporal rows tr and trp developed, extending transversally between pores H and K; longitudinal row g long, passing row m posteriorly and relatively close to row h; infraorbital row 6 long, ventrally extending to lower margin of preopercle, its ventral (6i) and dorsal (6s) originating opposite to each other; posterior lateral rows: row h long, reaching anteriorly above middle of opercle. Coloration: body pale fawn and brownish; margin of scale pockets dark brown pigmented, yielding a reticulated pattern; five brown blotches on flanks in lateral midline from below first dorsal fin to caudal peduncle; caudal fin with six or seven distinct dark vertical bands.