Malacoctenus delalandii (Valenciennes, 1836) in Cuvier & Valenciennes, 1836

Carvalho-Filho, Alfredo, Sazima, Ivan, Lima, Sergio Maia Queiroz, Almeida, Daniel, Mendes, Liana, Dias, Ricardo Marques, Britto, Marcelo R. & Gasparini, João Luiz, 2020, Review of the genus Malacoctenus (Actinopterygii: Labrisomidae) from the Southwestern Atlantic, with description of two new species, Zootaxa 4819 (3), pp. 499-520 : 511-514

Malacoctenus delalandii (Valenciennes, 1836) in Cuvier & Valenciennes, 1836 .

English Name: Brazilian Blenny

Portuguese (Brazilian) Name: Macaquinho comum

(Figure 6-B, Table 3)

Diagnosis: Malacoctenus delalandii is distinguished from its southwestern Atlantic congeners by the following combination of characters: Dorsal-fin rays XX,9–11, rarely XIX or XXI; anal rays II,17–21; pectoral-fin rays14 or 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 without scales; breast usually fully scaled in males, and usually naked in females. Two or three pores from preopercular canal onto opercle. Color pattern dominated by five to six, rarely seven, saddle-like bars on body, extending to spiny dorsal fin.

Description: Proportional measurements and counts in Table 3. Description based on literature and 58 non-type specimens. Body elongated. Head moderate, snout pointed, forehead steep; eye 23–35% in head length; upper lip separated from snout by deep groove; jaws subequal with about 14 pairs of pointed, slightly curved teeth; a crescent patch of villiform teeth on vomer; palatine toothless; maxillary not reaching orbit; gill rakers on first arch 2–4 + 6-8; nasal cirrus simple or bifid (occasionally triple or quadruple, rarely absent), arising from posterior border of short tube of anterior nostril and often reaching to or beyond posterior nostril when depressed; supra orbital cirri branches 4 to 6 over each eye, its length equal or larger than half orbit diameter; nuchal cirri 12–18 on each comb, paired or with one cirrus less, 24–36 (often more than 30), the longest reaches beyond dorsal-fin origin; space between nuchal cirri combs often very narrow, contained 1.5 to ten times in comb´s base. Two or three pores from preopercular canal onto opercle. Pores on ventral side of head: 4–6 mental, 2–6 symphysial and 6–10 interopercular.

Dorsal fin continuous, with three sections: first three spines decrease in length, followed by fourth to eighth or ninth spines progressively longer behind which last spines are successively shorter, the antepenultimate shorter than penultimate; last spine longer varying from one third to slightly less than half length of first and longest soft ray; soft rays decreasing in height, last one joined to body by a membrane for most of its length. Caudal fin slightly emarginate to slightly rounded with 13 unbranched, segmented rays, followed above and below by a single non-segmented ray and several procurrent spines. Anal fin continuous, the 16 th to 18 th rays the longest; first anal spine length 2/3 to 3/4 of second anal spine; first anal ray almost 1/3 longer than second anal-fin spine; anal-fin membrane notched at tip of each ray; last anal-fin ray not attached to body by membrane. Pectoral fin elongate, fifth or sixth lower rays usually longest. Pelvic fin second ray longer than third, usually not reaching anus; length of third, inner, shortest pelvic-fin ray, contained 2.5 to 3.0 times in second pelvic-fin ray.

Body covered with cycloid scales except pre-pelvic and immediate surrounding area. Head naked. Breast usually fully scaly in males and usually naked in females. Scales on midline before the dorsal fin absent; base of pectoral fin without scales; lateral line complete, running high anteriorly, down-curved below 10 th to 12 th dorsal-fin spines and straight along mid-body posteriorly. All fins naked.

Remarks: Upon describing Malacoctenus aurolineatus and M. erdmani, Smith (1957) stated that M. delalandei (sic) has scales on the pre-pectoral area. However, Springer (1959a), Springer & Gomon (1975), Williams (2003), and Wirtz (2014), stated that the aforementioned area (pectoral-fin base) has no scales, a statement that we agree with after examining 26 specimens. According to Eschmeyer et al. (2017), the original spelling, delalandii , is acceptable and delalandei is misspelled.

Coloration. The color pattern varies considerably between individuals. Males are usually more brightly colored than females.

Color in alcohol: Background varying from brown to tan, with five or six dark, rarely seven, irregular saddlelike bars on body, extending to spiny dorsal fin, rarely on fin-rayed dorsal fin. The saddles vary from dark to light brown and usually are not outlined by dark spots. The lower apices of the saddles are often somewhat constricted below the midline of the body. The interspaces below the midline of the body are rarely uniformly light, and usually have dark irregular patches and those with constricted lower apices of the saddles may form a horizontal row of large, irregular blotches. Lower sides of body light to tan often with dark reticulations or irregular markings. Vertical fins membranes transparent, with dark and/or pale dots on soft rays; anterior dorsal fin usually conspicuously pale; pectoral fin may have lower rays orange to yellowish; pelvic fins orange to yellowish. Head peppered with dark dots or irregular blotches; snout dark often with two faint pale lines from eye to lip; two, rarely one, dark bars from eye to lower part of head. A light to orangish bordered dark ocellus on opercle, more conspicuous on males and often with a broad orange-yellowish blotch on females. Pre-pectoral area with faint dark irregular markings.

Color in life: Basic coloration as above but brighter, the head and body with numerous pale dots, the saddles peppered with red and blue dots; several irregular rusty blotches behind eye.

Distribution: Malacoctenus delalandii is known from Belize, Central America, and Puerto Rico, Caribbean, to Santa Catarina State, Southern Brazil. This scaly blenny is associated with shallow reefs where it feeds on benthic invertebrates.