Meiacanthus abruptus, Smith-Vaniz, William F. & Allen, Gerald R., 2011

Smith-Vaniz, William F. & Allen, Gerald R., 2011, Three new species of the fangblenny genus Meiacanthus from Indonesia, with color photographs and comments on other species (Teleostei: Blenniidae: Nemophini), Zootaxa 3046, pp. 39-58 : 41-44

Meiacanthus abruptus new species

Figures 2‒5 , Table 1

Holotype. MZB 20022, 36.6 mm SL, male, Indonesia, Komodo Island, Slawi Bay, 8°36.746'S, 119°29.338'E, 1.5 m, mangrove shore, clove oil and hand-net, Gerald R. Allen and Mark V. Erdmann, 6 Sept. 2010.

Paratype. WAM P.30964.003, 31.4 mm SL, female, Indonesia, Komodo Island, mangrove shore at Point Slawi, 8°37'S, 119°29'E, 2 m, spear, Gerald R. Allen, 2 April, 1995.

Diagnosis. A species of Meiacanthus (subgenus Meiacanthus ) with major portion of dentary gland dorsally positioned and held in place laterally by dorsolateral flange of dentary; dorsal fin IV, 25 or 26; color pattern characterized by a single black mid-lateral stripe that is bluntly rounded at its terminus on the caudal-fin base; dorsal fin pale distally with a wide black proximal stripe; white or yellow stripe above and below dark mid-lateral stripe; belly and flanks pale to rich yellow.

Description. (when values differ, those of holotype are given first). Dorsal fin IV, 26 (25). Anal fin II, 15 (14). Pectoral fin 13-13. Caudal fin: procurrent rays 6+5; segmented rays 13, inner rays not elongated or deeply incised. Vertebrae: precaudal 13 + caudal 20. A pair of canines posteriorly in each jaw, those in lower jaw very large with a deep frontal groove; incisor teeth in lower jaw 22 (20); in upper jaw 19 (18). Lateral line present, terminating below 5th or (7th) dorsal-fin ray; mandibular and posttemporal pores 3; median supratemporal pores a very closely spaced pair (single pore).

Sexual dimorphism moderately developed in pelvic and caudal fins: pelvic fin 27.0 (15.3) % SL; longest caudal-fin ray 33.6 (18.9) % SL; inner caudal-fin ray 23.2 (22.1) % SL.

Color pattern in preservation: The most distinctive feature of the color pattern is a dark stripe extending through the eye to the center of the caudal fin where it is bluntly rounded at its terminus on the caudal-fin base. The stripe is about half the width of the eye diameter, completely envelops the gill opening but does not extend onto the pectoral-fin base. On the postorbital region of the snout, the stripe is slightly wider than the pupil diameter but becomes narrower as it extends onto the snout. Another dark stripe, which gradually becomes narrower posteriorly, extends from above the eye, along the dorsal contour of the body, onto the dorsum of the caudal peduncle and a short distance onto the bases of several of the upper caudal-fin rays. A narrow, pale, predorsal stripe separates the dorsalmost dark stripe from its counterpart and extends anteriorly to interrupt the dark mid-lateral stripe as it partially encircles the snout ( Fig. 4 ). The body is otherwise pale but sprinkled with fine dark brown chromatophores. The dorsal fin is conspicuously bicolored, pale distally with the dark dorsal contour body stripe extending uninterrupted onto the basal half of the fin. The other fins are mostly pale, except for the dark stripe on the caudal-fin base; caudal- and pectoral-fin rays are darkly outlined.

Color in life ( Figs. 4–5 ): The color pattern of the live holotype is very similar to that described above. The dark stripes are blackish with an intervening white stripe. There also is a white stripe of equal width immediately below the dark mid-lateral stripe. The breast and adjacent lower portion of the side are yellowish, and the cheeks and lower half of the head are light pinkish grey. Fish from the Bali region differ from those from Komodo Island most notably in having a much richer yellow coloration that also includes the cheeks and belly; the white stripe that borders the dark mid-lateral stripe ventrally is also narrower.

Comparisons. Meiacanthus vicinus closely resembles the new species, except in life the lateral stripe is dark brown (versus bluish-black), and it tapers to a point at its terminus on approximately the anterior fourth of the caudal fin (versus being bluntly rounded and terminating on the caudal-fin base); M. vicinus also has more total vertebrae 34 (vs. 33). Life colors of M. abdustus differ from the remaining three species of Meiacanthus with a single mid-lateral stripe as follows: the body of M. geminatus is golden yellow below the brown lateral stripe and the dorsal fin is mostly dark brown except for a very narrow pale margin; in M. luteus the pale area above the lateral stripe is golden yellow and there is no wide, dark, proximal dorsal-fin stripe; M. vittatus has a grey body and fins and the lateral stripe is bordered above by a distinct narrow white stripe. Meiacanthus vittatus further differs in having the inner caudal-fin rays of males elongate, and the mid-lateral stripe moderately encroaching onto the pectoral-fin base (slightly encroaching in M. luteus ), versus no encroachment in the other species; M. luteus also differs in having more pectoral-fin rays, 15 or 16 (versus 13); and M. geminatus differs from all four species in having the midlateral stripe distinctly positioned below the center of the caudal-fin base (versus centered on the base).

Habitat and distribution. The habitat at the Komodo type locality consists of a shallow (1–2 m) coral reef adjacent to a thin band of mangroves along the shoreline of a large sheltered bay. Live coral cover was estimated at about 30 percent. The holotype was captured when it entered an abandoned worm tube in a small Porities coral formation. Meiacanthus abruptus has also been observed and photographed in depths of 2–4 m at Secret Bay, Gilimanuk, 8°9.771'S, 114°27.116'E, a large mangrove-lined bay on the western end of Bali across the narrow channel from Java. About 15 individuals were encountered on an isolated patch reef consisting of almost 100 percent live coral.

Etymology. From the Latin abruptus , meaning broken off, in allusion to the mid-lateral stripe that abruptly ends on the caudal-fin base. The name is here used as a noun in apposition.

Dorsal-fin rays Anal-fin rays Total vertebrae Total pectoral-fin rays

Species 24 25 26 27 14 15 16 33 34 35 36 26 27 28 29 30 M. abruptus 1 1 1 1 2 2

M. vicinus 1 1 1 1 2 1 ― 1

M. abditus 8 6 3 11 1 10 3 10 ― 4 M. cyanopterus 3 4 3 2 2 2 3 2 1 ― 3 1 2 M. erdmanni 1 1 1 1

Figures

FIGURE 2. Meiacanthus abruptus, holotype, MZB 20022, 36.6 mm SL, male, Indonesia, Komodo Island. Photo by S. J. Raredon.

FIGURE 3. Meiacanthus abruptus, WAM P. 30964.003, 31.4 mm SL, female, Indonesia, Komodo Island. Photo by S. J. Raredon.

FIGURE 4. Meiacanthus abruptus, holotype, Indonesia, Komodo Island. Photo by G. R. Allen.

FIGURE 5. Meiacanthus abruptus, Bali. Photo by G. R. Allen.