Allen'S Blenny

Dorsal fin XII,13-14 (typically 13), deeply notched between spinous- and segmented-ray sides. Anal fin II,14-16 (typically 15). Vertebrae 10 + 21-22 (typically 22). Dentary incisor teeth 41to 50 (rarely more than 47; includes anterior canine teeth, very similar in appearance to incisors); posterior canines one on each side. Lateral line lacking vertical pairs of pores, terminating posteriorly at point between vertical from interspace between bases of 10th and 11th dorsal-fin spines and vertical at base of 12th dorsal-fin spine (usually ending at or anterior to base of 11th spine). With short cirrus on posterior rim of anterior nostril, absent on anterior rim. With an intensely dark banded pattern on the body with occasional spot-like intensifications of pigment within the bands; with a large, dark spot on the pectoral-fin base and in the axil.

Oviparous, distinct pairing (Ref. 205).

Dorsal spines (total): 12; Dorsal soft rays (total): 13 - 14; Analspines: 2; Analsoft rays: 14 - 16

Common in lagoon and outer reef areas.

Common in lagoon and outer reef areas. Oviparous. Eggs are demersal and adhesive (Ref. 205), and are attached to the substrate via a filamentous, adhesive pad or pedestal (Ref. 94114). Larvae are planktonic, often found in shallow, coastal waters (Ref. 94114).

Ecsenius alleni

Ecsenius nov. sp. Allen and Russell, 1986:95 [Rowley Shoals, Scott Reef].

DESCRIPTION.—Dorsal fin XII, 13–14 (usually 13), deeply notched between spinous- and segmented-ray portions. Anal fin II, 14–16 (usually 15). Pectoral fin 13. Caudal fin 13. Vertebrae 10 + 21–22 (usually 22). Dentary incisor teeth 41 to 50 (rarely more than 47; includes anterior canine teeth, which differ little, if at all, in appearance from incisors); posterior canines one on each side. Lateral line without vertical pairs of pores, terminating posteriorly at point between vertical from interspace between bases of tenth and eleventhth dorsal-fin spines and vertical at base of twelfth dorsal-fin spine (usually terminating at or anterior to base of eleventh spine). Short cirrus present on posterior rim of anterior nostril, none on anterior rim.

Preserved Color: Head: snout dark; cheeks darkest dorsally with slightly darker spot at about midpostorbital margin giving rise to slender, faintly dusky stripe, which extends posteriorly to lateral-line pores at dorsoposterior margin of opercular area; cheeks ventral to dusky stripe without distinct markings. Body: broad, diffusely dusky stripe at same level as slender postorbital stripe variably present; up to 12 dark bands extending ventrally from dorsal-fin base; anteriormost band usually represented only as dusky spot at bases of first two spines; next 5 bands below spinous dorsal-fin base, usually fading out at about midside (often two offset dusky bands inserted ventrally in pale interspaces between posteriormost two of these 5 bands); next 5 bands extend ventrally from dorsal body contour below segmented-ray portion of dorsal fin, often with spotlike intensification in each band; posteriormost body band often faintly dusky or present only as dark spot continuous with diffuse, dark, posteroventrally extending marking on caudal fin; diffuse, posterodorsally extending marking on caudal fin ventral to just described marking. Pectoral-fin base and axil each with large, dark spot that extends with decreasing intensity onto fin rays basally. Dorsal fin with dusky markings along rays. Anal fin broadly dusky. Pectoral and pelvic fins unremarkable.

Live Color (Plate 12: figure 2): Head dusky brownish dorsal to mid-orbital level, with three fine, bright-white stripes extending posteriorly from postorbital margin; dorsalmost two stripes very short, ventralmost stripe extends posteriorly to posterior opercular margin; cheeks pinkish below ventralmost stripe; eye black with two bright-white stripes passing across surface and continuing around snout. Body stripes blackish, but those on posterior half of body dusky ventral to body midline; dorsal half of body darker, bluish gray anteriorly, faintly dusky pink on posterior two-thirds, row of about 8 squarish bright-white spots on ventral half. Dark spot on fleshy pectoral-fin base indigo blue anteriorly, black posteriorly; spot with narrow, bright-white anterior border. Fins unremarkable.

COMPARISONS.—Among the eight species of the Opsifrontalis Group, Ecsenius alleni is most similar to the banded phases of E. axelrodi and E. dilemma in having an intensely dark banded pattern on the body with occasional spot-like intensifications of pigment within the bands. It also appears to be similar to the banded phase of E. bathi, but the bands are much fainter in the latter species. Numerous trenchant dissimilarities in color pattern exist among these species. In particular, E. alleni lacks a striped phase, which is present in the other three species, and has a large, dark spot on the pectoral-fin base (and in the axil), which distinguishes E. alleni from all other species of Ecsenius.

ETYMOLOGY.—Named for my colleague Gerald R. Allen, who collected most of the specimens and recognized that they represented an undescribed species, as well as for many other courtesies extended to me.

DISTRIBUTION.—Known only from Scott Reef and Clerke and Mermaid reefs, Rowley Shoals, each about 300 km off northwestern Western Australia. According to Allen, E. alleni was common in both lagoon and outer reef areas at depths from about 1–35 m.

HOLOTYPE.—WAM P27666-017, male, 28.2 mm SL, Mermaid Reef, central lagoon, 15–18 m, G.R. Allen, 26 July 1982.

PARATYPES.—USNM 279474 (2 specimens: 30, 32 mm SL), collected with the holotype; WAM P27665-001 (4:28–32), WAM P27668-014 (1:26), WAM P27658-013 (1:27), WAM P27663-010 (1:26), WAM P27660-009 (4:24–32), WAM P27662-026 (2:30, 33), WAM P27656-021 (1:32), WAM P28022-048 (19:22–34), all collected at Clerke Reef by G.R. Allen between 21–27 July 1982, at depths from 2 to 35 m; AMS I.21318-014 (1:27), Scott Reef, S. Talbot, 21 September 1979; NTM S.11371-047 (7:18–28), NTM S.11376-033 (3: 23–38), NTM S.11387-017 (1:28), NTM S.11389-031 (3: 22–23), all collected by B. Russell between 7–13 September 1984.

Ecsenius alleni, known commonly as the Allen's blenny, is a species of combtooth blenny in the genus Ecsenius. It is found in coral reefs in the eastern Indian ocean, specifically in western Australia. It can reach a maximum length of 3.4 centimetres. The blennies feed primarily off of plants and algae. The specific name honours the ichthyologist Gerald R. Allen.