Meiacanthus (Meiacanthus) abditus Smith-Vaniz

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 : 51-54

Meiacanthus (Meiacanthus) abditus Smith-Vaniz and M. cf. abditus .

Meiacanthus abditus was originally described ( Smith-Vaniz 1987) from the Sulu Archipelago based on juveniles (10.2–29.3 mm SL) obtained at Jolo Island with dynamite in 3–6 m, and one 48.3 mm SL adult male from Sirun Island, trawled in 31– 38 m. Although the color pattern is somewhat faded in all these specimens (collected by the M/V Albatross in 1908–1909), no dark stripe is evident on the anal-fin base and the pair of dark mid-lateral stripes extends a short distance onto the caudal fin. In the adult male the inner rays of the caudal fin are only weakly incised and not elongated, the dorsal fin has a dark stripe that extends the entire length of the fin and is about twice the width of the pale proximal area of the fin; in the 29.3 mm SL female the dark dorsal-fin stripe is about equal to the width of the anterior pale proximal area of the fin but it narrows posteriorly and fades completely before reaching the end of the fin. In both sexes the dark snout stripe contacts the margin of the upper lip anteriorly (see Smith- Vaniz 1987: Fig. 3 b).

Smith-Vaniz (1987:9) briefly discussed a species of Meiacanthus occurring at Flores Island (8°35'S, 122°13'E), based on a photograph provided by Rudie Kuiter, noting that it shares with M. crinitus the elongate inner caudal-fin rays of adult males and has a head pattern most like M. abditus but differs from that species in several other aspects of its color pattern. Kuiter and Debelius (2006:644) subsequently published a color photograph of " M. abditus " from Flores Island, here reproduced as Fig. 17 . This species is clearly not M. abditus based on the elongate inner caudal-fin rays of males, presence of a dark stripe along the anal-fin base and different pigmentation of the dorsal fin in both sexes (compare Figs. 17–18 with description of M. abditus dorsal fins in above paragraph). Females ( Fig. 18 ), like other sexually dimorphic species of Meiacanthus , have relatively short pelvic fins and lack elongate inner caudal-fin rays. Kuiter (pers. comm.) noted that Meiacanthus sp. is relatively common at Flores on the outer islands, mainly Pomana, along walls near and in caves in about 20–25 m in current prone areas.

Allen et al. (2003:340) published a color photograph ( Fig. 19 ) of what appear to be relatively small individuals, identified as Meiacanthus abditus , from Sabah, Malaysia, that had formed aggregations among gorgonians and black coral. A slightly less cropped image of the same photograph shows two individuals with a dark anal-fin stripe and another one with it very faint or absent. What may be the same species of Meiacanthus was also observed and photographed ( Fig. 20 ) on a vertical wall in 16–20 m at Menjangen I. off Bali. These juvenile Meiacanthus were aggregating in small groups of 20–30 fish around gorgonian sea fans, a behavior like that of the Sabah fish. It is possible that these are juveniles of the adult Flores Meiacanthus but in the absence of specimens or observations of both juveniles and adults together at any locality, we are unable confidently make that determination. We anticipate resolution of this quandary once specimens become available, followed by a formal description of the new species.

Meiacanthus limbatus is the only other double-striped species of Meiacanthus that has a dark stripe on the anal-fin base but it differs most notably in having a completely dark chin and a yellow caudal fin.

Figures

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

FIGURE 17. Meiacanthus cf. abditus = n. sp., male (in front) and female (behind), Flores Island. Photo by R. H. Kuiter.

FIGURE 18. Meiacanthus cf. abditus = n. sp., large female, Flores Island. Photo by R. H. Kuiter.

FIGURE 19. Meiacanthus cf. abditus, Sabah, Malaysia. Photo by G. R. Allen.

FIGURE 20. Meiacanthus cf. abditus, Menjangan I., off Bali. Photo by G. R. Allen.