Brachygenys jessiae

Brachygenys jessiae, called the black-striped salema, is a marine ray-finned fish and a member of the grunt family Haemulidae. It lives only in the eastern Pacific Ocean, restricted to the waters surrounding the Galápagos Islands.

Description

This fish has a fairly slender, elongated body, which sets it apart from most of its relatives. Its head is cone-shaped, with large eyes and a short, diagonal mouth where the lower jaw sticks out. The teeth are very small and arranged in bands on the jaws and the roof of the mouth.

The dorsal fin is split into two separate parts: a front section with 10 spines and a rear section with one spine and 13 to 14 soft rays. The anal fin has three small spines and 10 to 11 soft rays. The black-striped salema can grow up to 30 cm (12 inches) in total length.

Its back is a dark silvery-grey, often with hints of yellowish green, yellowish blue, or blue-green. This color fades to a paler silver on the sides and to silvery-white on the belly. Seven black horizontal stripes run along each side.

Habitat and biology

It is found at depths from the surface down to 20 meters (66 feet). In these shallow waters, it forms dense schools.

During the day, these schools stay near rock walls and over rocky slopes. The fish feed on plankton and small fish. They reproduce by laying eggs (oviparous), spawning in distinct pairs.

Systematics

The species was first formally described in 1890 by American ichthyologists David Starr Jordan and Charles Harvey Bollman, with the type location given as Isla Santa Maria in the Galápagos Islands, Ecuador. Some authorities place it in the monotypic genus Xenocys. This reclassification happened after molecular studies showed that the genus Haemulon was paraphyletic, and that Haemulon chrysargyreum (the type species of Brachygenys) grouped with Xenistius californianus.

As a result, the genus Brachygenys was revived to include that species, the other species from Xenistius, and this one. This change is accepted by Catalog of Fishes but not by Fishbase. The specific name jessiae honors Jordan’s second wife, Jessie Knight Jordan.