Diagnosis: The modal fin-ray count of D-XX,12 A-II,20-21 and P-14-15 indicates Malacoctenus triangulatus and falls within the range for M. aurolineatus, L. bucciferus, and L. haitiensis. (DNA) Ecology: The saddled blenny is the most commonly observed labrisomid on coral reefs in the region (M. macropus are generally more common but they are less conspicuous and less associated with coral habitats). Saddled blennies have one of the widest of distributions for regional reef fishes; they are found in Bermuda, Florida, the Gulf of Mexico, the Bahamas, all of the Caribbean Sea including NE Venezuela, as well as in Brazil and on many of its offshore islands. Their larvae are common in collections. Description: Pre-transitional larvae: Body long, moderately narrow, and thin with a large round eye, pointed snout, and small terminal 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 full complement of melanophores on the top of the head comprises a scattering of large spots grading down to small, even tiny, spots (typically 10 or more per side, often many more), sometimes with the large spots arranged in two inward-facing crescents in a U- or O-shape. Occasional larvae have incomplete complements, sometimes just one or two large melanophores with one or a few smallerl spots. There is a cheek melanophore on each side. Typical lightly-marked larvae have no melanophores along the dorsal-fin base. Many lightly-marked larvae do have a characteristic single melanophore near the base of the largest dorsal procurrent caudal-fin ray, but no additional caudal-fin base melanophores. (A "dorsal-row" variant with melanophores at the base of some or all of the soft dorsal-fin rays and even along the base of some dorsal-fin spines occurs among some early transitional larvae. These larvae can also have melanophores along the base of the caudal-fin rays. It is unclear whether these larvae represent a regional variant in the Antilles or are only a variation during early transition and appear the same as lightly-marked larvae at earlier stages.) Along the ventral midline there is a melanophore at the mid-isthmus (rarely an additional one on the anterior isthmus) and one deep behind the pelvic-fin base. Along the anal fin there is a melanophore at the base of each anal-fin soft ray (sometimes not the last), followed in some larvae by one to three spots along the ventral midline of the caudal peduncle (many lightly marked larvae have none). A row of internal melanophores overlies the vertebral column, one per vertebra, along the mid- and rear body, not continuing onto the caudal peduncle. Additional internal melanophores include those at the nuchal midline, otic capsule, and overlying the abdominal organs. Transitional stage: M. triangulatus larvae in transition develop patches of small surface melanophores over the head, including a short bar down from the orbital rim at 5:30 o'clock and a broad eye-stripe from the orbital rim to the mid-maxilla. In addition, the melanophores along the lower edge of the fleshy pectoral-fin base form a single patch midway from the body to the fin-ray insertion, which later develops into a Y-shaped bar. Fine metamorphic melanophores extend onto the body forming complex patches, mostly on the upper body, roughly in the shape of wide inverted triangles. Multiple long cirri form on the nape, over the eye, and over the nasal tube. Juveniles: M. triangulatus juveniles develop a large dark spot at the base of the second and third dorsal-fin spines that extends onto the body, followed by a row of five wide inverted triangles extending to the tail. Analogues: In general, M. triangulatus larvae can be distinguished from most other Malacoctenus larvae by having more than 10 melanophores per side on the top of the head, a pattern shared only by some larvae of M. versicolor. The two species are also very similar in size and morphology, but fortunately can be reliably separated by fin-ray counts: 18 dorsal-fin spines and 18-19 anal-fin soft rays in M. versicolor vs. 20 dorsal-fin spines and 20-21 anal-fin soft rays in M. triangulatus. In addition, M. versicolor larvae have an obvious third pelvic-fin ray about two-thirds the length of the second vs. less than half the second and often inconspicuous in M. triangulatus and a row of melanophores along the caudal-fin base vs. at most a single melanophore (at the base of the largest dorsal procurrent ray) in M. triangulatus larvae (with rare exceptions). Larval M. boehlkei also have a short third pelvic-fin ray, a feature shared only by M. triangulatus and L. haitiensis, and can have multiple spots over each quadrant of the cranium; they are best distinguished from M. triangulatus by having relatively long posterior dorsal-fin spines and usually more fin rays (a rare specimen of M. triangulatus could have the same count). Since the markings, morphology, and size of M. triangulatus larvae can be intermediate between typical Malacoctenus and Labrisomus, separation from Labrisomus larvae can be problematic. This is especially true for those variants with melanophores along the dorsal and caudal-fin bases and/or a reduced complement of head melanophores, thus resembling the pattern for many Labrisomus larvae. The fin-ray count is helpful, with most M. triangulatus having a high fin-ray count of D-XX,12 and A-II,21, fortunately non-overlapping with several of the slimmer Labrisomus that can share morphology with Malacoctenus (L. nuchipinnis, L. conditus, L. cricota, as well as the two small species, L. nigricinctus and L. albigenys; the latter two with many fewer head melanophores than M. triangulatus). The most similar Labrisomus larva is L. haitiensis, which can share both the high fin-ray counts and the inconspicuous short third pelvic-fin ray and its head melanophore pattern of a U-shape of six large spots can overlap with reduced-complement M. triangulatus larvae (and the occasional L. haitiensis larva have a few additional small spots). L. haitiensis larvae, however, always have the row of melanophores along the dorsal-fin base and a pair of prominent melanophores near the tip of the upper jaw (the former rare in M. triangulatus) and have a different dorsal-fin outline, with longer posterior spines. Some of the remaining 19 and 20-spined Labrisomus species can overlap in fin-ray counts with M. triangulatus, but those larvae have an obvious third pelvic-fin ray which is inconspicuous in M. triangulatus and often uniformly sized head melanophores (vs. graded tiny to large). Transitional M. triangulatus larvae are distinguished by fin-ray counts, persistent larval melanophores, and their metamorphic melanophore pattern, i.e. the combination of the 5:30 o'clock bar, an eye stripe to the mid-maxilla, and a single patch of melanophores (later developing into a Y-shape) along the lower edge of the pectoral-fin base. They can be separated from transitional Labrisomus by the metamorphic melanophore pattern as well as the dorsal-fin outline (third-to-last spine less than a third the length of the longest soft rays vs. often half or more) and long cirri (about a pupil width or more vs. short, esp. orbital). Once they develop a large dark spot at the front of the spinous dorsal fin, juveniles can be separated by that feature from most other Malacoctenus species except M. gilli, which share the spot but also have a distinctive ocellus at the rear spinous dorsal fin, and M. boehlkei, which have the dorsal-fin spot ocellated (with yellow) and elevated some distance above the base of the fin. The inverted-triangle pattern for which the species is named is not diagnostic in juveniles- the basic pattern is shared by several congeners. Juvenile L. nuchipinnis, L. conditus, and L. cricota have a similar dorsal-fin spot and some may be missing their opercular ocellus or dark spot; in that case the dorsal-fin outline (with medium-length posterior spines), a longer third pelvic-fin ray, and reticulated markings on the body should distinguish them from M. triangulatus. Later they diverge markedly in morphology becoming bulkier with a large mouth and smaller eyes.
Malacoctenus triangulatus, the saddled blenny, is a species of labrisomid blenny fish native to the Atlantic Ocean as well as the Gulf of Mexico and the Caribbean Sea from southern Florida to the coast of Brazil. It inhabits rocky shores and reefs at depths of from near the surface to 40 metres (130 ft) though most common shallower than 3 metres (9.8 ft). This species can reach a length of 7.5 centimetres (3.0 in) TL. It can also be found in the aquarium trade.[2]
Malacoctenus triangulatus, the saddled blenny, is a species of labrisomid blenny fish native to the Atlantic Ocean as well as the Gulf of Mexico and the Caribbean Sea from southern Florida to the coast of Brazil. It inhabits rocky shores and reefs at depths of from near the surface to 40 metres (130 ft) though most common shallower than 3 metres (9.8 ft). This species can reach a length of 7.5 centimetres (3.0 in) TL. It can also be found in the aquarium trade.
