Jarocho Goby

description

Description: Morphometrics of all type specimens (15.3 – 27.2 mm SL) as a percent of standard length (mean): head length, 26.8 – 28.5 (27.6); body depth at dorsal origin, 15.5 – 18.3 (17.8); caudal peduncle depth, 10.5 – 12.9 (11.5); eye diameter, 8.2 – 10.5 (9.1); snout length, 4.0 – 5.9 (4.8); upper jaw length, 9.1 – 11.7 (10.2); pectoral fin length, 11.5 – 22.2 (18.1); pelvic fin length, 14.0 – 17.0 (15.1); caudal fin length, 15.4 – 20.3 (18.0). Fin ray counts (mode): D. VII, 11 – 12 (11); A. 9 – 11 (11); pectoral rays, 15 – 17 (16). None of the dorsal spines are elongated. The body is unscaled and somewhat laterally compressed. The subterminal mouth is U-shaped, lacks a rostral frenum, and the tongue is truncate. The conical teeth are set in 1 – 2 rows. Males have a slender, conical genital papilla; females have a blunt papilla. Coloration: In life, the body is a translucent, dark bluish-grey. A disjunct, bright yellow lateral stripe occurs just above the midline. The anterior segment of the yellow stripe originates anterior to the eye and extends posteriorly to the dorsal edge of the preoperculum. The posterior segment of the yellow stripe begins at the caudal peduncle and ext

Two new species of Elacatinus (Teleostei: Gobiidae) from the Mexican coast of the Gulf of Mexico

description

Figures 1,2 Elacatinus jarochus (nomen nudum), Reef Environmental Education Foundation newsletter, Spring 2005.

Two new species of Elacatinus (Teleostei: Gobiidae) from the Mexican coast of the Gulf of Mexico

diagnosis

Diagnosis: Elacatinus jarocho is readily distinguished from other species of Elacatinus (s. s.) by the disjunct yellow lateral stripe that appears as a dash over the eye and on the caudal fin, a yellow medial stripe on the snout, and a black ovoid to rectangular spot at the base of the caudal fin, immediately ventral to the yellow dash.

Two new species of Elacatinus (Teleostei: Gobiidae) from the Mexican coast of the Gulf of Mexico

discussion

Remarks: Elacatinus jarocho was found between 3 – 25 m depth on high profile coral reefs typically dominated by Montastrea cavernosa (Linneaus), M. annularis (Ellis and Solander), Colpophyllia natans (Houttuyn) and skeletal reef framework. Elacatinus jarocho joins E. atronasus (Böhlke & Robins) as the only two species in the genus to school in the water column. Small to large aggregations (12 – 60 individuals) of E. jarocho were normally found close to the reef near high profile corals or overhangs. Such reef structure presumably provides shelter from direct sunlight because aggregations were usually observed in darker, shaded areas rather than in direct sunlight. Individuals of E. jarocho, unlike E. atronasus, were never observed stationary on any substrate, but rather hovered continuously about 5 – 25 cm above the reef (Fig. 2), frequently in association with Coryphopterus hyalinus Böhlke & Robins or C. personatus (Jordan & Thompson). This species was not observed to clean other species or interact in other symbiotic relationships. Small and large individuals coexisted in the same aggregations and did not display territorial or hierarchical behaviors. Individual fish would often,

Two new species of Elacatinus (Teleostei: Gobiidae) from the Mexican coast of the Gulf of Mexico