Diagnosis: The modal fin-ray count of D-XVIII,12 A-II,18 and P-14 is shared by Labrisomus nuchipinnis and the related cryptic species L. conditus and L. cricota, as well as by Malacoctenus versicolor. The fin-ray count falls within the lower range for L. guppyi and L. kalisherae and the upper range for L. albigenys and L. nigricinctus. (DNA) Ecology: The true hairy blenny is the largest member of its family in the region (adults can reach more than six inches long) and they are the most commonly encountered species of Labrisomus in the Caribbean Sea (but not Florida). They occupy a variety of shallow-water habitats, but are usually found in mixed coral and rocky substrates. The recent discovery of two additional allied cryptic species described from Brazil but widespread in the region complicates identifications within the group. L. nuchipinnis is widely distributed: from Bermuda and the Bahamas, as well as the Caribbean Sea to mainland Brazil. They are replaced on Noronha off Brazil by L. conditus and share the Brazilian coast with L. cricota. DNA sequencing results thus far show that outside of Brazil and Florida, L. nuchipinnis well outnumber the cryptic species (or are the only species). L. nuchipinnis barcode DNA sequences vary little over the entire region from Bermuda to Brazil. In Florida, the vast majority of hairy blennies sequenced prove to be L. conditus, with a few L. cricota. Of course, it is likely that all three species could be found in S. Florida where Caribbean and Florida lineages of many reef fishes often overlap. True hairy blennies vary greatly in markings and colors, with some overlap in appearance with the cryptic species, although many smaller specimens (and all juveniles?) show the sharp and narrow white rim around a rounded opercular ocellus that likely confirms the ID as L. nuchipinnis. However, when the ocellus is not round, or not well-delineated by a thin white ring, or the white ring is broken, or there is no ocellus, the marking does not separate adults of the three species (I have found DNA-confirmed adult L. nuchipinnis can have any or all of these patterns, including a mix of any version on each side of the fish). Their larvae are occasional in collections. Description: Pre-transitional larvae: Body long, narrow, and thin, with a medium eye, pointed snout, and terminal medium-sized mouth. Long continuous dorsal and anal fins with a short and narrow caudal peduncle. Pectoral fins long, reaching past the vent, and pelvic fins long and thread-like; the third pelvic-fin ray is about 3/4 the length of the second. There are some small spines along the rim of the preoperculum that no longer project as larvae approach and complete transition. The full complement of large melanophores on the top of the head typically consists of a row of three on each side of the head, usually in a narrow-U, i.e. the spots get closer to the dorsal midline anteriorly; quite often there are just five (rarely 7) in a V with a single melanophore at the vertex at or near the midline of the forebrain (note that in both cases the rear side-by-side pair are typically more widely spaced than the middle pair). Often there is an additional near-surface melanophore at the midline behind the mid-brain lobes, completing a narrow-O (not the deep nuchal midline melanophore). There can sometimes be one or, uncommonly, a few smaller additional melanophores. There are no melanophores just behind the tip of the upper jaw, but there can be a small melanophore at the anterior nostril on each side. There is a cheek melanophore on each side. There is a prominent melanophore, or sometimes a few, on the inner aspect of the cleithrum visible within the gill cavity on each side. Melanophores run along the base of all of the soft dorsal-fin rays and some of the dorsal-fin spines, typically including some anterior spines, usually starting at spine 8 (can be at 5 or even 2), then 11-12, and from 14 rearward. A few individuals develop a small melanophore along the dorsal midline of the caudal peduncle. A small melanophore is often located on the body at the lateral midline on the caudal peduncle. A vertical line of melanophores develops along the base of the caudal-fin segmented rays (first proximal, then distal) and thin linear melanophores are spaced out along each side outlining the full-length of the three lower caudal-fin segmented rays (occasionally a few along the upper three rays as well). Along the ventral midline there are melanophores at the isthmus and deep behind the pelvic-fin base. There is occasionally a small melanophore or two at the surface on the ventral aspect of the abdomen, but no extensive speckling of the peritoneum is visible from below. Along the anal fin there is a melanophore at the base of each anal-fin soft ray, followed by one, sometimes two, along the ventral midline of the caudal peduncle. A row of internal melanophores overlies the vertebral column, spaced about every third vertebra, along the mid- and rear body, continuing onto the caudal peduncle. Additional internal melanophores include those at the nuchal midline, otic capsule, and overlying the abdominal organs. Transitional stage: L. nuchipinnis larvae develop metamorphic melanophores over the head and body simultaneously. The head is mostly uniformly speckled or reticulated with fine melanophores while the body is uniformly reticulated with a network of thin lines not separated into bars. As in other Labrisomus, the prominent head melanophores begin to shrink, spread, or fragment into smaller spots, or narrow into short lines (usually the middle pair); later they are obscured by underlying speckling and overlying shading. Juveniles: L. nuchipinnis juveniles develop a pattern of reticulations and dark bars on the body, an opercular ocellus, usually fully rounded with a complete thin white rim, and a dark spot on the first three dorsal-fin spine membranes. Juvenile blennies of this group can vary greatly in the degree of these dark markings; some light individuals intensify their white spots and fade, or sort of pixelate, their melanocytes, while others are darkly-reticulated and some can be almost uniformly dark. Analogues: Pretransitional L. nuchipinnis are probably identical to the larvae of the cryptic species L. conditus and L. cricota. Although the first dorsal-fin spine is shorter than the third in juvenile and adult L. nuchipinnis and L. conditus vs. longer in L. cricota, DNA-confirmed L. nuchipinnis larvae can have equal-length anterior dorsal-fin spines and it is likely that the fin-spine differences only emerge at or after transition. Larvae of the other 18-spined species, L. albigenys and L. nigricinctus, have many fewer melanophores on the head and usually none at the dorsal and caudal-fin bases. L. haitiensis larvae share the slim morphology with L. nuchipinnis larvae as well as the row of melanophores along the spinous dorsal-fin base including some of the first 10 spines, and, to varying degrees, most of the other markings of larval L. nuchipinnis, but they can be distinguished by a short and inconspicuous third pelvic-fin ray, a pair of melanophores behind the tip of the upper jaw (absent on L. nuchipinnis larvae), extensive speckling of the ventral abdominal viscera visible through the abdominal wall, the absence of inner cleithral melanophores, and higher fin-ray counts. The remaining Labrisomus species usually have an unmarked spinous dorsal-fin base or, at most, melanophores extending only to some of the spines of the rear half of the spinous dorsal-fin. Those with more melanophores typically have the pair of melanophores behind the tip of the upper jaw (absent on L. nuchipinnis larvae) as well as additional melanophores on top of the head, multiple in each quadrant (vs. the basic U or V-pattern on L. nuchipinnis), and rarely have the inner cleithral melanophores. Lightly marked specimens can be problematic because they are often missing the pair at the tip of the jaw and share the basic U or V-pattern of L. nuchipinnis; in that case they can be distinguished by the absence of the inner cleithral melanophores and the absence of the melanophores lining the lower caudal-fin segmented rays (or, rarely, a very few at the proximal ends of the rays). L. nuchipinnis larvae can resemble large Malacoctenus larvae since they are relatively slim and have smaller mouths than some other large Labrisomus species. Nevertheless, the row of melanophores along some of the spinous dorsal-fin base separates L. nuchipinnis from all Malacoctenus larvae other than the occasional variant specimen of M. triangulatus. The latter, however, do not have melanophores outlining the caudal-fin segmented rays or the central caudal peduncle spot and usually have more numerous and graded-size head spots (as well as higher median-fin ray counts, a short third pelvic-fin ray, and a different dorsal-fin outline, with short posterior spines). Transitional L. nuchipinnis larvae are distinguished by fin-ray counts, persistent larval melanophores, and their metamorphic melanophore pattern, i.e. a uniform pattern of fine reticulations. The other Labrisomus species develop uniform shading or bars, except for the two allied cryptic species which share the reticulations of L. nuchipinnis: transitional L. cricota may be distinguished by the first dorsal-fin spine being longer than the third, and transitional L. conditus probably cannot be separated until the oval dark spot develops on the operculum. L. nuchipinnis are also separated from transitional Malacoctenus larvae by having shorter cirri (especially orbital), the fine metamorphic melanophores on the head mostly diffusely distributed (vs. in discrete patches) and developing at the same time as body markings (vs. head first), and the dorsal-fin outline. Juvenile L. nuchipinnis are separated from most other labrisomids by the long snout, anterior dorsal fin spot, and a thin-edged rounded opercular ocellus. Juveniles of L. conditus and L. cricota share the anterior dorsal-fin spot and body reticulations and bars, but apparently do not have a round well-delineated opercular ocellus: juvenile L. conditus have an oval and not sharply-outlined ocellus on the operculum and L. cricota have a diffusely broad and orange edge to the opercular ocellus and the first two dorsal-fin spines distinctly longer than the third (vs. equal or shorter in the other two species). Two other Labrisomus have a well-outlined ocellus, L. nigricinctus and L. filamentosus, but the former have narrow bars and a very pointed snout and the latter have the first three dorsal-fin spines greatly extended and higher median-fin ray counts. Two other species have a less well-outlined ocellus: L. guppyi, with no dorsal-fin spot, a blunt snout, and 19 dorsal-fin spines; and L. haitiensis, with the opercular spot not outlined as an ocellus, a blunt snout, an inconspicuous third pelvic-fin ray, and 20 dorsal-fin spines. The 19- and 20-spined Labrisomus species all have a blunt snout, less than two-thirds the bony orbit diameter. Juvenile Malacoctenus all have pointier snouts with smaller mouths, have very short posterior dorsal-fin spines (except M. macropus), and none have a well-outlined opercular ocellus.
Labrisomus nuchipinnis, the hairy blenny, is a species of labrisomid blenny native to the Atlantic Ocean from the coast of the Americas to the African coast. This species prefers areas that give them crevices and holes to shelter in such as areas with rock or rubble substrates, reefs or beds of seagrass. They can be found in shallow water only a few centimeters deep to a depth of 10 metres (33 ft) though they are much rarer deeper than 5 metres (16 ft). Carnivorous, they prey on such animals as crustaceans, gastropods, echinoderms such as urchins and brittle stars, polychaete worms and other fishes. This species can reach a length of 23 centimetres (9.1 in) TL. They can also be found in the aquarium trade.[2]
Artist's interpretation of Labrisomus nuhipinnis
Labrisomus nuchipinnis, the hairy blenny, is a species of labrisomid blenny native to the Atlantic Ocean from the coast of the Americas to the African coast. This species prefers areas that give them crevices and holes to shelter in such as areas with rock or rubble substrates, reefs or beds of seagrass. They can be found in shallow water only a few centimeters deep to a depth of 10 metres (33 ft) though they are much rarer deeper than 5 metres (16 ft). Carnivorous, they prey on such animals as crustaceans, gastropods, echinoderms such as urchins and brittle stars, polychaete worms and other fishes. This species can reach a length of 23 centimetres (9.1 in) TL. They can also be found in the aquarium trade.
