Brazilian Blenny

Diagnosis: The modal fin-ray count of D-XX,10 A-II,19 and P-14 indicates Malacoctenus delalandii or M. gilli. Many M. aurolineatus share this fin-ray count, but their mode is 11 soft dorsal-fin rays. Some M. erdmani share the median-fin ray count but have a mode of 16 pectoral-fin rays. L. kalisherae, L. bucciferus, and L. haitiensis can also overlap the fin-ray count. The species is often spelled as Malacoctenus delalandei. (DNA) Ecology: The Brazilian blenny is found mostly in the southern Caribbean, where it seems to replace M. versicolor. The species has been collected from the inshore reefs of Belize south along the Central American coastline and across to NE Venezuela, where it is the most abundant species of the genus. Their range extends south to mainland Brazil, but not to the offshore islands of Noronha and Rocas. They are small blennies found on inshore shallow reef areas with complex structure; within most of their Caribbean range they are not commonly observed by divers. Their larvae are unknown or unrecognized in collections. Description: (larvae unknown) Juveniles: M. delalandii juveniles have dark bars on the body that extend uninterrupted over the full-width of the dorsal fin. The dark bars on the fin membranes distinctively expand outwards, often meeting at the fin edge. There is a dark spot on the lower operculum, often outlined and elongated, but not an obvious round ocellus. Analogues: Juveniles of M. versicolor can appear quite similar, but their first dorsal-fin spine is notably longer than the rest (vs. M. delalandii with the first spine about equal or shorter than the mid-fin spines), the bars that extend onto the fins do not expand to meet at the edges, the bar under the last dorsal-fin spines is narrow and separate from the next dark patch forward (vs. widening anteriorly as it spreads onto the fin in M. delalandii), and the dorsal-fin spine count is lower. An uncommon barred variant of juvenile M. macropus can also have bars on the body extending uninterrupted over the dorsal fin, but they also do not expand to meet at the edges, their fin-ray counts are different, and they have long single cirri (vs. multiple in M. delalandii and M. versicolor). Labrisomus nigricinctus can share the barred pattern, but they have an obvious round opercular ocellus.

This species is distinguished from its southwestern Atlantic congeners by the following set of characters: D XX,9-11 (rarely XIX or XXI); A II,17-21; pectoral-fin rays14-15 (rarely 13); length of third pelvic-fin ray contained 2.5 to 3.0 times in second pelvic-fin ray; lateral-line scales 48-56; total nuchal cirri 24-36; pectoral-fin base and midline before dorsal-fin no scales; breast usually fully scaled in males, often naked in females; pores 2-3 from preopercular canal onto opercle. Colouration: pattern dominated by 5-6 (rarely 7), saddle-like bars on body, extending to spiny dorsal fin (Ref. 123106).

Dorsal spines (total): 20; Dorsal soft rays (total): 9 - 11; Analspines: 2; Analsoft rays: 7 - 21

Cleaned by Elacatinus figaro observed off the coast of São Paulo, southeastern Brazil (Ref. 40102).

Occurs in shallo reefs (Ref. 123106), on sandy bottoms and Thalassia testudinum beds (Ref. 13628). Feeds mainly on crustaceans but also on gastropods and worms (Ref. 13628).

Malacoctenus delalandii is a species of labrisomid blenny native to the Atlantic Ocean and the Caribbean Sea from Guatemala to Brazil. This species is an inhabitant of coral reefs being found in sandy areas and around beds of the seagrass Thalassia testudinum. It can reach a length of 8.2 centimetres (3.2 in) TL. The specific name honours the French explorer and naturalist Pierre Antoine Delalande (1787-1823), who collected the type.