Diagnosis: The modal fin-ray count of D-XX,11 A-II,20 and P-13 indicates Labrisomus bucciferus, as well as some chaenopsids of Emblemariopsis. Note that almost 90% of L. bucciferus individuals have 20 dorsal-fin spines. This fin-ray count falls within the upper range for L. gobio and L. kalisherae and the lower range for L. haitiensis (usually with 14 pectoral-fin rays), and overlaps the range for Malacoctenus delalandii, M. gilli, M aurolineatus, and M. triangulatus. (DNA) Ecology: The puffcheek blenny is a common small blenny found mostly in shallow rocky, seagrass, and mixed coral habitats. The species is widespread in the region, found in Florida, the Dry Tortugas in the Gulf of Mexico, Bermuda, the Bahamas, and across the Caribbean Sea except NE Venezuela. However, they are common only in warmer and clear-water areas such as the Bahamas, the Antilles, and the offshore barrier reef and atolls in Belize and notably uncommon in Florida and absent from most of the Gulf of Mexico and Venezuela. It appears to be replaced by L. kalisherae in cooler and/or turbid-water areas such as Florida and Venezuela and the inshore reefs of Belize. Unfortunately, the 19, 20, and 21-spined Labrisomus are very similar morphologically and are frequently confused in guidebooks and photographs. All six species share the blunt-headed and goggle-eyed appearance, at least as juveniles, i.e. the snout length (bony orbit to jaw tip) is less than two-thirds of the orbit diameter. Adult puffcheek blennies are recognized in the field mostly by the lack of an opercular spot or ocellus, dark lines behind the eye and pale spotting over the operculum, and relatively long first two dorsal-fin spines. Juveniles are particularly difficult to separate, since the distinguishing markings for each species are either not well-developed or shared by other species at this early stage (but see description below). L. bucciferus larvae are occasional in collections. Description: (pre-transitional larvae have not been identified, but the description is based on the transitional larvae; lightly marked larvae may be missing some of the melanophore complement) Pre-transitional larvae: Body long, narrow, and thin with a medium eye, pointed snout, and terminal medium-sized mouth. Larvae can have the normal body shape or develop a hunched-over appearance (tip of snout below the lateral midline of the body). 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 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, usually with one to a few additional spots over the forebrain lobes (note that the rear side-by-side pair are often more widely spaced than the middle pair). There is a prominent melanophore on each side just behind the tip of the upper jaw. There is a cheek melanophore on each side. Melanophores run along the base of all of the soft dorsal-fin rays as well as some of the posterior dorsal-fin spines. A vertical line of melanophores develops along the base of the caudal-fin segmented rays curving around to the base of the larger procurrent rays. Along the ventral midline there are melanophores at the isthmus and deep behind the pelvic-fin base. There is no extensive speckling of the peritoneum visible through the ventral abdominal wall, but some more heavily marked larvae can show some peritoneal speckling on the upper sidewalls of the abdomen. Along the anal fin there is a melanophore at the base of each anal-fin soft ray, followed by none to three 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. bucciferus larvae in transition develop metamorphic melanophores over the head and body simultaneously. The head and body are mostly uniformly speckled with fine melanophores, although some transitional larvae develop an indistinct pattern of dark bars. Juveniles: L. bucciferus juveniles have dark bars on the body that extend onto the fins. The last dark bar ends on the caudal-fin base outlining three light spots. There is usually no dark spot or ocellus on the operculum, which is typically covered with small pale spots. The dark lines radiating from the rear orbit are usually prominent. The anal and pectoral fins have a few dark bands, but are not heavily spotted, and the pelvic fin-rays usually have 3-4 dark bands. The first two dorsal-fin spines become long, more than half the body depth at the dorsal-fin origin, and equal or longer then the mid-fin spines. Analogues: Based on the transitional stage, pretransitional L. bucciferus larvae share the pair of melanophores behind the tip of the upper jaw with the 19-spined species and L. haitiensis. Unlike those species, the extra melanophores in addition to the basic U or O head spot pattern may be limited to the forebrain lobes vs. over all quadrants (it remains to be confirmed if this pattern is consistent). Otherwise, they share melanophore patterns with the 19-spined species and the (usually) extra dorsal-fin spine may then be the only distinction from L. gobio and L. kalisherae (L. guppyi should have a shorter first dorsal-fin spine). L. haitiensis larvae usually differ in having abdominal speckling, melanophores at the base of dorsal-fin spines 8 or 9, and longer pelvic fins with a short third ray. The larvae of the chaenopsid blennies of Emblemariopsis can be distinguished by having a gap between the 3rd and fourth dorsal-fin spines, only 3 procurrent caudal-fin rays (vs. 6 or more), a slimmer body shape, and many fewer melanophores. Transitional L. bucciferus larvae are distinguished by fin-ray counts, persistent larval melanophores, and their uniform speckling of metamorphic melanophores. The pair of melanophores behind the tip of the upper jaw is shared only by the 19-spined species (L. gobio, L. guppyi, and L. kalisherae) and L. haitiensis. The transitional larvae of L. gobio and L. kalisherae have not been identified, but likely can only be distinguished by the fin-ray count. Transitional L. haitiensis as well as L. nuchipinnis, L. conditus, and L. cricota develop reticulated patterns over the body (vs. uniform speckling). The dorsal-fin outline separates transitional L. bucciferus from many congeners: the first spine is relatively long, about two to 2.5 times in the body depth at the dorsal-fin origin, and about the same length as the the mid-fin spines (vs. distinctly shorter, 3 times or more into body depth, in L. nuchipinnis, L. conditus, L. albigenys, L. nigricinctus, and L. guppyi, and well shorter than the mid-fin spines in the latter three species). Transitional L. bucciferus larvae are separated from transitional Malacoctenus larvae by the uniform markings over the head and body (developing at the same time), short cirri, and the dorsal-fin outline. The juveniles of the 19- and 20-spined Labrisomus are blunt-headed, compared to the 18-spined Labrisomus (other than L. albigenys), i.e. the snout length (bony orbital margin to the tip of the closed jaw) is less than two-thirds the bony orbit diameter. Small juveniles of the blunt-headed Labrisomus are difficult to identify to species, especially since some species described with opercular ocelli can have only a diffuse dark spot on the operculum when young. In addition, those species described without ocelli can often have an outlined dark spot on the operculum (but not a thin-rimmed ocellus) as juveniles. Juvenile L. bucciferus are difficult to separate from L. kalisherae by appearance, although fortunately L. kalisherae typically have only 19 dorsal-fin spines. The adult character of the number of pores at the submandibular symphysis does not apply to juveniles. The marking differences are quite subtle, with L. bucciferus having less spotted ventral and pectoral fins and fewer dark bands along the pelvic fin-rays (3 or 4 vs. 5 or 6), and more likely to show short dark lines radiating from the rear orbital rim and numerous small pale spots over the operculum. Juvenile L. haitiensis (and L. kalisherae) share the relatively long first dorsal-fin spines (often with white-shaded membranes) with L. bucciferus, but L. haitiensis have distinctly longer pelvic fins (reaching past the anal-fin origin and with 6-7 bands) with a short and inconspicuous third pelvic-fin ray, and often a dark opercular spot. Juvenile L. bucciferus are best separated from L. gobio and L. guppyi by having the pigment on the caudal-fin base outlining three light spots (vs. ending as a mostly straight vertical line) and higher fin-ray counts. In addition, L. gobio differ in having the dark bars on the body not extending onto the fins and L. guppyi have a much shorter first dorsal-fin spine (less than a third of the body depth at the dorsal-fin origin vs. half or more) and rapidly develop an opercular ocellus. L. albigenys are best distinguished by their short first dorsal-fin spine and lower fin-ray counts. The remaining Labrisomus juveniles are distinguished by their opercular ocelli, longer snouts, and fin-ray counts i.e. L. nigricinctus and L. nuchipinnis (as well as L. conditus and L. cricota, both with less distinct ocelli), and L. filamentosus (blunt-snouted but with longer first dorsal-fin spines).
