Redescriptions and Synonymies of Species of the American–West African Genus Gobionellus (Teleostei, Gobiidae) with a Key to Species
The genus Gobionellus and its six included species are diagnosed and redescribed. All species share a unique cephalic lateralis canal structure, which extends from the tip of the snout to above the rear margin of the operculum with an A‘BCDFHKL’ pore pattern; a vertical row of sensory papillae on the rear field of the operculum and transverse suborbital rows; and a blunt, distally flared fourth neural spine that is spatulate in five of the six species. Three species are found in the eastern Pacific Ocean. Gobionellus daguae is known only from the lower portions of rivers in Panama and Colombia. Gobionellus liolepis has been collected in tidepools and on beaches along the coast of Panama, in the Miraflores locks, and over mud habitats up to 20 m deep off El Salvador. The third eastern Pacific species, Gobionellus microdon, is widespread in estuaries and in some fresh waters from Mexico to Ecuador. Gobionellus mystax is a junior synonym of this species. Two species are recognized from the western Atlantic Ocean. Gobionellus oceanicus is found in estuaries and inshore coastal waters from New Jersey to southern Brazil. The other species, Gobionellus stomatus, is limited to Brazilian estuaries. Gobionellus occidentalis is the only member of the genus from western Africa, where it inhabits tropical estuaries and coastal waters. A key to the species is provided.Abstract
Anterior vertebral column of a cleared-and-stained specimen of Gobionellus microdon illustrating the flared spatulate fourth neural spine (arrow)
Lateral view of the oculoscapular canal and sensory papillae rows of Gobionellus occidentalis. Canal pores are labeled according to Akihito et al. (1984). Labeled neuromast rows are posterior opercular row (p), horizontal midcheek row (b) and transverse suborbital cheek rows (1–5)
Cephalic sensory papillae rows and lateralis canal pores of Gobionellus microdon. (A) lateral view (B) dorsal view
(A) Gobionellus daguae (Eigenmann, 1918), USNM 257680, male, 96.6 mm SL, Rio Mira at Cabo Manglares, Colombia. (B) Gobionellus liolepis (Meek and Hildebrand 1928), FMNH 8480, female, 66 mm SL, Balboa, Canal Zone, Panama. Figure is reversed. (C) Gobionellus microdon (Gilbert, 1892), UMMZ 179934, male, 126 mm SL, Colima, Mexico. (D) Gobionellus occidentalis (Boulenger, 1909), MNHN 1967– 904, male, 132.3 mm SL, Togo. (E) Gobionellus oceanicus (Pallas, 1770). NLU 3201, male, 128 mm SL, Pilottown, Louisiana. (F) Gobionellus stomatus Starks, 1913. AMNH 3847, male, 82.0 mm SL, Natal, Brazil
Regression of jaw length (above) and caudal fin length (below) on standard length of male specimens of Gobionellus microdon. Diamonds = syntypes of Gobionellus mystax, dots = Guatemalan and Costa Rican specimens, squares = Mexican specimens
Contributor Notes
Museum of Natural History, University of Louisiana at Monroe, Monroe, Louisiana 71209–0504. pezold@ulm.edu