Symphurus melasmatotheca and S. undecimplerus (Cynoglossidae, Pleuronectiformes), Two New Eastern Pacific Tonguefishes with Eleven Caudal-Fin Rays

Abstract

Two new species of eastern Pacific tonguefishes with an unusual count of 11 caudal-fin rays are described. Symphurus melasmatotheca (southern Gulf of California to northern Peru) is characterized by having 11 caudal-fin rays, a welldeveloped pupillary operculum, 90-98 dorsal-fin rays, 74-80 anal-fin rays, 4952 total vertebrae, four hypurals, a 1-5-3 (less frequently, 1-4-3) pattern of interdigitation of dorsal pterygiophores and neural spines, and 82-98 longitudinal scale rows. Symphurus melasmatotheca also has a unique pigmentation pattern that consists of a black peritoneum, crossbanding on the body and posterior part of the head, a distinctively black isthmus, light speckling on the inner lining of the ocular-side opercle, and an unpigmented inner lining of the opercle on the blind side of the body. Symphurus undecimplerus (Gulf of Tehuantepec to northern Peru) is distinguished from its congeners by a combination of 11 caudal-fin rays, a well-developed pupillary operculum, a 1-5-3 (less frequently 1-4-4 or 1-54) pattern of interdigitation of dorsal pterygiophores and neural spines, 97-105 dorsal-fin rays, 80-87 anal-fin rays, 52-56 total vertebrae, 95-112 longitudinal scale rows, an unpigmented or infrequently lightly spotted peritoneum, crossbanding on the body and posterior part of the head, a dark (but usually not black) isthmus, and absence of pigment on the inner linings of the opercles on both sides of the body. Differences in geographic and bathymetric distributions between species are also noted.