Eastern Atlantic Tonguefishes (Symphurus: Cynoglossidae, Pleuronectiformes), with Descriptions of Two New Species
Abstract:Six species of symphurine tonguefishes, including two previously undescribed, from the Mediterranean Sea and eastern Atlantic Ocean (including the Azores, Madeira, Ascension, and St. Helena) are described and illustrated. A key to the species is provided. Symphurus vanmelleae, a rarely captured and poorly-known bathyal species (361-944 m), previously thought to be conspecific with S. ligulatus, is now considered distinct. The species is known from 65 specimens collected off the continental shelf and upper continental slope of tropical West Africa (14°N–12°S). Symphurus vanmelleae is unique among eastern Atlantic tonguefishes in its combination of twelve caudal-fin rays, ten abdominal vertebrae, black peritoneum, and 1-2-2-2-1 pattern of interdigitation (ID pattern) of dorsal pterygiophores and neural spines. Two other deep-sea species, S. ligulatus (205–1,024 m) and S. nigrescens (47–1,400 m, usually 90–350 m), have sympatric but mostly allotopic distributions in the Mediterranean Sea and adjacent portions of the eastern Atlantic Ocean. Symphurus ligulatus is the only eastern Atlantic (Mediterranean — 18°N) species possessing 14 caudal-fin rays, black peritoneum and a 1-2-2-2-2 ID pattern. Symphurus nigrescens, a widespread species (Bay of Biscay, Azores, throughout the Mediterranean, to ca. 7°S), is distinguished from all other eastern Atlantic species by the combination of 12 caudal-fin rays, 1-3-2 ID pattern, black peritoneum, and lack of small scales on the blind-side dorsal- and anal-fin rays. Symphurus norman; occurs in moderate depths (22–75 m) on the continental shelf off tropical West Africa (12°N–9°8) and is readily distinguished from all other eastern Atlantic species by a unique combination of an unpigmented or lighly spotted peritoneum, pepper-dot pigmentation on the blind side of the body, 1-3-3 ID pattern, and presence of small scales on blind-side dorsal- and anal-fin rays. Two new species occurring on remote oceanic islands in shallow water on sandy bottoms are S. lubbocki (Ascension Island) and S. reticulatus (St. Helena, Madeira). These are among the smallest species in the genus and are readily distinguished from other eastern Atlantic tonguefishes by a combination of 12 caudal-fin rays, 1-3-2 ID pattern, unpigmented peritoneum, absence of scales on the blind-side dorsal- and anal-fin rays, and presence of 101–109 small scales in a longitudinal series along the body. Primary differences between these two diminutive species are cream-colored ocular-side pigmentation with several incomplete, brown crossbands in S. lubbocki versus dark chocolate-brown body color with an alternating series of X- and Y-shaped markings in S. reticulatus, dark brown blotches on the dorsal and anal fins in S. reticulatus versus their absence in S. lubbocki, and several morphometric features (S. lubbocki with greater head length, predorsal distance, upper jaw length, dorsal-fin base length, and snout length).
Document Type: Research Article
Publication date: 1990-09-01
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