Guaymus Goby, Quietula guaymasiae
Guaymus Goby, Quietula guaymasiae. Fish caught from the Marua Estuary, Puerto Peñasco, Sonora, April 2021. Length: 6.0 cm (2.4 inches). Catch, photograph and identification courtesy of Jacob Avelar, Ventura, California.
Guaymus Goby, Quietula guaymasiae. Fish caught from the Marua Estuary, Puerto Peñasco, Sonora, April 2021. Length: 6.0 cm. Catch and photograph courtesy of Chris Moore, Peoria, Arizona. Identification courtesy of Jacob Avelar, Ventura, California.
The Guaymus Goby, Quietula guaymasiae, is a member of the Goby or Gobiidae Family that is known in Mexico as gobio de Guaymas. Globally, there are two species in the genus Quientula, both of which are found in Mexican waters of the Pacific Ocean.
The Guaymus Goby has an elongated slender slightly compressed body with a long head that has eyes on top, a large mouth that reaches to the gill opening that tapers to a blunt point equipped with a single series of teeth on the lower jaw and the front half of the upper jaw. They vary in color being gray to mottled dorsally transitioning to white ventrally. They have six double white spots on their sides alternating with blackish areas extending into the caudal peduncle. They have a white spot behind the eye and the cheeks have two dark bands that extend obliquely down and back from the eyes. The anal, pectoral and pelvic fins are plain; the caudal fin has 5 or 6 wavy bars, the dorsal fins have four series of dark spots, the Their anal fin has 1 spine and 12 to 15 rays and a long base; their caudal fin is rounded; their first dorsal fin has 5 spines; their second dorsal fin has 1 spine and 14 rays; their pectoral fins have rays and are short not reaching the pelvic fins; and their pelvic fins are fused to form a disc. They have 12 short blunt gill rakers. Their body is covered with small smooth scales.
The Guaymus Goby is an abundant demersal species that is found in the intertidal zone in the sand flats and mud flats in shallow hypersaline coastal lagoons, river mouths and mangrove estuaries at depths up to 7 m (17 feet). They reach a maximum length of 8.5 cm (3.3 inches). They are nighttime predators that consume amphipods, crab larvae, hydrozoans and large quantities of polychaetes worms. In turn they are preyed upon by a wide variety of fishes and by octopuses. Reproduction is oviparous with the eggs attached to the walls of the burrows which are then guarded by the males until they hatch. They can survive out of water having the ability to breath air. The Guaymus Goby is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, diet, growth, habitat, longevity, movement patterns, and reproduction.
The Guaymus Goby is similar in in body shape and appearance to six additional Gobies found in the Sea of Cortez, the Delta Mud-sucker, Gillichthys detrusus (uniform pale color), the Bright Goby, Ilypnus luculentus (uniformly lightly colored), the Cheekspot Goby, Ilypnus gilberti (dorsal fin with a red and white margin), the Longjaw Mud Sucker, Gillichthys mirabilis (dark stripe on the cheek; rows of dark blotches on the sides), the Shadow Goby, Quietula y-caida (caudal base with Y-shaped blotch), and the Shortjaw Mudsucker, Gillichthys seta (rows of dark and yellow blotches on the sides).
The Guaymus Goby is a resident of Mexican waters of the Pacific and is endemic to the Sea of Cortez being found throughout the Sea of Cortez south to LaPaz, Baja California Sur.
From a conservation perspective the Guaymus Goby is currently considered to be of Least Concern with stable, widely distributed population. They are small in stature, seldom seen by humans, and of limited interest to most. Regionally they have been adversely affected by coastal development and mangrove destruction.