Auchenionchus variolosus (Valenciennes 1836)

Carnivore (Ref. 50629).

Juveniles feed primarily on amphipods but shift to diet of decapods as adults (Ref. 94105).

Auchenionchus variolosus (Valenciennes)

Clinus variolosus Valenciennes in Cuvier and Valenciennes, 1836:381 [Valparaiso, Chile; holotype, MNHN A.2170].

Calliclinus validus DeBuen, 1962:80 [zone of Valparaiso; holotype EBM 10.390, apparently destroyed].

DESCRIPTION.—Counts, including those of holotype, are summarized in Table 3. Salient characters are presented in the key. Dorsal fin XXIV,11–12; total dorsal-fin elements 35–36; anal fin II,22; pectoral fin 14; pelvic fin I,3; caudal fin 13; lateral-line scales 56–59; vertebrae 12–13 + 29–30 = 42 (based on 5 specimens).

Morphometric characters of four specimens examined: SL 101.2–178.0 mm; head length 29.7–31.5; head depth 21.9–24.1; head width 16.6–21.6; upper jaw length 12.1–14.5; eye diameter 5.0–6.1; snout length 8.0–10.0; interorbital width 3.1–3.4; predorsal length 21.1–24.3; preanal length 49.4–53.3; caudal-peduncle depth 7.9–8.6; caudal-peduncle length 6.9–8.2; pectoral-fin length 22.0–24.4; pelvic-fin length 14.2–17.5; length first dorsal-fin spine 5.6–7.1; length fourth dorsal-fin spine 8.0–11.2.

Orbit with cluster of 8–20 cirri (more than 10 in specimens longer than 157 mm), some simple, others bifid to multifid; all cirri contiguous at base but no common raised stalk present. In 3 specimens the nape cirrus consists of 4–10 free tips arrayed along a palmate, flattened, transverse flap (in USNM 208293 the nape cirrus is absent on one side; the holotype of C. variolosus has a simple cirrus on one side; the cirrus on the other side is missing); nasal cirri of 3–6 branches arising from a common base. Each jaw with about 20 widely spaced, large, recurved teeth on border; teeth variable in size, largest anteriorly; patch of small teeth posterio-medially; palatines and vomer covered with small teeth; no cirrus-like projections at tips of fin rays; anal fin not bound to caudal peduncle; no scales on head anterior to angle of opercle, none on operculum or gill membranes, weakly developed or absent on belly, pectoral-fin base and fins; lateral line horizontal, high on body anteriorly, then abruptly dropping to midline; numerous tubercle-like head pores around orbit, nasal, and postorbital region dorsally, numerous sensory pores on head. No wartlike protuberances covering top of head.

Color in alcohol (USNM 208293): Ground color deep tan with slightly reddish hue; head darker than body, not obviously patterned, lightly pigmented beneath jaws and on branchiostegal membrane; head cirri unpigmented; body and dorsal fin traversed by five well-developed, black bars; bars wide (each covering four rays), obvious on dorsal fin, becoming indistinct black mottling toward anal fin; first bar crosses first two dorsal spines, its posterior margin even with angle of opercle, its anterior limit coalescing indistinguishably with darkly pigmented head; belly unmarked; caudal fin mottled, without distinct bands; anal fin dark brown at base, fin rays unpigmented distally; pectoral fin brown, uniformly pigmented; pelvic fin paler than pectoral, unmarked; peritoneum black.

One specimen (SIO 65–678) differs from above description in having dark brown spots on jaws and belly and distinct bands on caudal and pectoral fins. This is the only female specimen available, and these differences may be sexually associated. In many species of clinids the females are more heavily spotted than the males.

The holotype of Clinus variolosus, the largest specimen of the species available, is gutted and in poor condition. Much of the color pattern has faded, but it is possible to discern that the entire head, body, and all the fins are densely covered with small dark spots.

DISCUSSION AND COMPARISON.—DeBuen (1962) placed A. variolosus in the genus Calliclinus, in which he also recognized four other species: geniguttatus, coventryi, guttulatus and, validus. DeBuen’s allocation of C. coventryi was based solely on Fowler’s (1940) inadequate description. C. coventryi is a synonym of Calliclinus geniguttatus. DeBuen’s C. geniguttatus and C. guttulatus appear to be misidentifications of specimens referable to Auchenionchus variolosus, and his new species, C. validus, also appears identifiable with A. variolosus. If one ignores DeBuen’s apparently inaccurate fin-ray counts, his main characteristics for separating the several species of Calliclinus (except C. coventryi) were the form and number of the nuchal and orbital cirri. In our five specimens of A. variolosus the nuchal cirri are variable, and the orbital cirrus, though always multifid, varies in its degree of branching. DeBuen’s new species, C. validus, is based on a single specimen, the description of which agrees with the holotype of C. variolosus, except that there are only four gill rakers on the lower limb of the first arch. None of our specimens, including the holotype, have less than seven gill rakers, although the lower two or three are usually rudimentary. We prefer at this time to treat C. validus and all other Auchenionchus with 14 pectoral-fin rays as a single species, A. variolosus.

Besides pectoral-fin ray number, A. variolosus may be differentiated from other species of the genus by its well-developed orbital cirrus, with some bifid to multifid members, reduced squamation, lateral-line pattern, black peritoneum, and low number of dorsal-fin spines (24 rather than 25–26) and segmented anal-fin rays (22, rather than 23–24).

SPECIMENS EXAMINED.—Chile: Valparaiso, MNHN A. 2170 (holotype of C. variolosus, 246); Tome, USNM 77380 (1:178); Montemar, USNM 208293 (1:162); La Ventana, SIO 65–670 (1:101); SIO 65–678 (1:157).

Auchenionchus variolosus is a species of labrisomid blenny endemic to the Pacific waters off the coast of Chile. While juveniles primarily consume amphipods, their diet shifts to decapods as the mature. This species can reach 18 cm (7.1 in) in total length.