Axelrod's Clown Blenny

Ecsenius axelrodi

DESCRIPTION.—Dorsal fin XII,12–14 (usually 13), deeply notched between spinous and segmented-ray portions. Anal fin II,14–16 (usually 15). Pectoral fin 12 or 13 (usually 13). Caudal fin 13. Vertebrae 10 + 21–23 (usually 22). Dentary incisor teeth 38–46 (includes anterior canine teeth, which differ little, if at all, in appearance from incisors); posterior canines usually one on each side. Lateral line without vertical pairs of pores, terminating posteriorly at point between vertical from interspace between dorsal-fin spines 9 and 10 and vertical from spine 12. Cirrus present on posterior rim of anterior nostril; none on anterior rim.

Preserved Color: Two markedly different color pattern types occur in E. axelrodi: banded (Figure 44a) and striped (Figure 44b). Of the 73 specimens available, 45 are banded and 28 are striped. Both color-pattern types were taken in the same collections and neither pattern is correlated with size or sex.

Banded Pattern: Head dusky dorsally; dusky area margined ventrally by dark postorbital stripe of variable intensity, stripe fading somewhat posteriorly on head and ending at abruptly darker, ventroposteriorly angled spot on body ventral to anterior end of dorsal fin. Cheeks pale ventral to postorbital stripe. Five slender, dark bands on body; bands restricted to region below segmented-ray portion of dorsal fin, sometimes fainter or interrupted at midside of body. Dark spot dorsally on caudal peduncle, extending as stripe onto caudal-fin rays, occasionally extending ventrally, forming faint (sixth) body band; dusky spot on caudal fin ventral to stripe. Dark spot on midside anterior to anteriormost body band; up to 6 dark spots on dorsal body contour below spinous dorsal fin; ventroposteriorly angled dark spot (mentioned above) below anterior end of lateral line, occasionally only faintly indicated, variably continuous with faint or dark stripe extending posteriorly from orbit. Head generally darker dorsal to postorbital stripe. Fleshy pectoral-fin base dusky, frequently with included immaculate, pale band; axil faintly dusky, unremarkable. Pelvic fins immaculate.

Striped Pattern: Head similar to that of banded specimens. Three intensely dark stripes, narrower than pale interspaces, on body; dorsalmost stripe extends along dorsal body contour for length of dorsal-fin base; middle stripe usually originates as dark spot posterior to orbit, decreases greatly in intensity on remainder of head, then markedly increases in intensity as slightly ventroposterior spot-like deflection below anterior end of lateral line, and continues, sometimes with slight interruption, to caudal peduncle, where it becomes ventroposteriorly directed and decreases in intensity as it continues on caudal fin; ventralmost stripe originates in pectoral-fin axil and is dusky from origin to point over posterior portion of abdomen, where stripe becomes intensely dark and extends onto caudal fin, decreasing greatly in intensity at stripe's posterior end. One to 4 dusky or dark spots in pale area between two dorsalmost stripes in region below posterior half of spinous dorsal fin, and up to 6 faint bands or faint to dark spots in pale area between two ventralmost stripes in region below segmented-ray portion of dorsal fin; faint indications of the 6 bands may also appear in pale area between two dorsalmost stripes. Other markings similar to those appearing in banded pattern.

Live Color: Based on color photographs taken in wild at Rabaul, New Britain.

Banded Pattern: Head blackish dorsal to midorbital level; cheeks pinkish below midorbital level; blackish area with three fine, pale-white stripes extending posteriorly from postorbital margin (hence enclosing a dark stripe); dorsalmost two stripes shortest, extending anteriorly through black dorsal two-thirds of eye and across snout; ventralmost stripe extends anteriorly along suborbital margin and across snout, interrupted posteriorly at posterior opercular margin, beginning again on body and extending posteriorly to midbase of caudal fin, becoming gradually deeper posteriorly; stripe has fine, dusky dorsal and ventral margins and is interrupted by black body bands; two deep, pinkish-orange stripes on body interrupted by black bands; third, slender, orange stripe-like area along dorsal body contour below spinous dorsal fin. Orange stripe on fleshy pectoral-fin base with white dorsal and ventral margins.

Striped Pattern: Head brown suffused with yellow dorsally, anteriorly, and ventroanteriorly, cheeks pinkish; iris of eye dorsally with three black spokes alternating with three bright-yellow spokes, ventrally yellow and white; fine, bright-yellow stripe at 3 o’clock position on postorbital margin, extending short distance posteriorly; fine, bright-yellow stripe margining orbital rim ventrally, extending posteriorly to posterior margin of opercle; dusky-brown postorbital stripe between the two fine, bright-yellow stripes, extending posteriorly and gradually decreasing in intensity to posterior opercular margin; two fine, bright-yellow stripes extending transversely across snout between anterior orbital margins. Black spot with fine, bright-white ventral margin on body in area above pectoral-fin axil; fleshy pectoral-fin base with bright-orange stripe margined ventrally by fine, bright-white stripe; two black stripes on body with dusky bands between; areas dorsal to dorsalmost black stripe and between black stripes, grayish; area white ventral to ventral stripe.

COMPARISONS.—E. axelrodi appears to be most similar and closely related to E. dilemma and E. bathi, which are unique within the Opsifrontalis Group in having banded and striped forms. Ecsenius axelrodi is most readily distinguished from the other two species in having an oblong, dark spot (banded form) or oblong enlargement of the dark stripe in the area below the origin of the lateral line (see comparisons sections under E. dilemma and E. bathi, for more detailed comparison).

DISTRIBUTION.—Admiralty Islands, New Britain, and Solomon Islands.

ETYMOLOGY.—Named in honor of Dr. Herbert R. Axelrod in recognition of his numerous and continuing important contributions in support of ichthyology.

HOLOTYPE.—USNM 231432, male, 35.2 mm SL, banded color pattern, Amot Island, Hermit Islands, Bismarck Archipelago, ocean side of reef at dropoff, 3–6 m depth, V.G. Springer and party, 30 October 1978.

PARATYPES.—USNM 220975 (54 specimens: 16–44 mm SL, collected with holotype); USNM 220976 (10:17–33), about 200–300 m SSE Pechu Island, Hermit Islands, reef dropoff on ocean side, about 18–21 m, V.G. Springer and party, 5 November 1978; USNM 220977 (4:15–28), same locality as holotype, about 30–36 m, V.G. Springer and party, 31 October 1978. WAM P28182-004 (2:20, 34), submarine base 7 km north of Rabaul, New Britain, G. R. Allen, 12 October 1983. CAS 56556 (2:30–33), outside of St. Mary's Harbor, near Gupuna Village, Santa Ana Island, Solomon Islands, J.E. McCosker, 1 April 1985, 25–30 ft [7.6–9.1 m] and 80–85 ft [24–26 m].