Alphestes immaculatus Breder, 1936

Taxonomy and Body Shape

Alphestes immaculatus, described by Breder in 1936, has a strongly compressed, deep body, large eyes, a short snout, and a straight forehead.

Fin Structure

Its dorsal fin has 11 spines and 17 to 19 soft rays, while its anal fin has 3 spines and 9 soft rays.

Preopercle Morphology

It has a rounded preopercle with a clearly serrated rear edge, and a large spine that projects downward and forward at the preopercle's angle; this spine is usually covered by skin.

Body Coloration

The head and body are marbled reddish brown, with indistinct bars and small dark and pale spots scattered across the head, body, and the dorsal, anal, and caudal fins.

Pectoral Fin Markings

The pectoral fins have 7 or 8 irregular horizontal rows of small dark spots across their surface.

Size

The maximum recorded total length of this species is 30 centimetres (12 inches), but most individuals are typically around 18 centimetres (7.1 inches) long.

Distribution Range

This species is distributed in the Eastern Pacific Ocean, ranging from southern Baja California and the Gulf of California south to Peru.

Island Distribution

It is also found around Mexico's Islas Marías and Revillagigedos, the Galápagos, Malpelo Island in Colombia, and Cocos Island in Costa Rica.

Habitat

Alphestes immaculatus is a secretive, well-camouflaged shallow water species that inhabits seagrass beds and rocky reefs at depths between 1 metre (3 ft 3 in) and 50 metres (164 ft 1 in).

Diurnal Behavior

During the day, it remains hidden in crevices or rests among seaweed, using its cryptic colouration to avoid detection by predators.

Burying Behavior

Occasionally, individuals will partially bury themselves in sand.

Nocturnal Feeding

They become active at night, foraging for their main prey: benthic invertebrates and small fishes.

Social Structure

This is normally a solitary species, though groups of up to 6 individuals have been observed.

Lifespan

It can live for up to nine years.

Immune Response Function

Muscle hepcidin expression may play an important role in the fish immune response.

HAMP1 Gene Function

Basal expression of the HAMP1 gene in the muscle tissue of A. immaculatus may represent a protective mechanism that acts against pathogen invasion before a strong immune stimulus occurs.