Curaçao, southern Caribbean

USNM 414915, 21.5 mm SL, female, Curasub submersible, sta. 12-7, southern Caribbean, Curaçao, east of downline off Substation Curaçao dock, near 12°05.069'N, 68°53.886'W, 157−167 m, quinaldine, 13 Aug 2012, D. R. Robertson, A. Schrier, B. Brandt, C. Castillo.

A species of Haptoclinus distinguished from its congener by the following combination of characters: dorsal-fin elements III-I-XIII, 12; anal-fin soft rays 19; pectoral-fin rays 12; precaudal vertebrae 12; first dorsal-fin spine longer than second dorsal-fin spine; scales absent; posterior nostril without fleshy flap; and trunk, dorsal- and anal fins with spotted pigment pattern in preservative.

Dorsal-fin elements: III-I-XIII, 12; anal-fin elements II, 19; ultimate pterygiophore of dorsal and anal fins supporting a single segmented soft ray. Pectoral-fin rays 12, 12. Pelvic-fin rays I, 3. Segmented caudal-fin rays 7+6, procurrent caudal-fin rays 6+5. All fin rays unbranched. Vertebrae 12+24=36. Three anal-fin pterygiophores anterior to first haemal spine.

Measurements (in mm): head length 6.6, snout length 1.3, eye diameter 1.0, body depth at fourth dorsal-fin spine 3.5, depth at caudal peduncle 1.0, greatest head width 5.4, body width at anus 2.0, width of bony interorbital 0.4, length of upper jaw 2.6, length of caudal peduncle 2.0, distance from snout to origin of dorsal fin 4.1, distance from snout to upper pectoral-fin base 5.9, distance from snout to insertion of pelvic fin 4.4, distance from snout to origin of anal fin 9.2, length of first dorsal-fin spine 4.1, length of second dorsal-fin spine 3.8, length of third dorsal-fin spine 1.5, length of fourth dorsal-fin spine 0.7, length of longest pectoral-fin ray 4.2, length of pelvic fin 4.1, length of longest caudal-fin ray 3.4.

Body without scales or scale pockets. Small, pointed teeth present in both jaws and on vomer and palatines; teeth uniserial except on anterior portion of premaxilla and dentary, where several teeth form an inner row. Anterior nostril with long tube; posterior nostril a simple opening with minute fleshy rim anteriorly but no fleshy flap; posterior nostril situated closer to eye than to anterior nostril. Mouth terminal and jaws equal. Upper edge of maxilla not sheathed by lacrimal when mouth closed; maxilla reaching vertical through posterior margin of orbit. Gill membranes broadly joined across but free of isthmus. Dorsal margin of upper lip free and continuous across tip of snout. Head lacking cirri. Pores of cephalic lateralis system as drawn for Haptoclinus apectolophus (Böhlke and Robins 1974: Fig. 3).

Dorsal fin originating on head about half way between verticals through posterior margins of eye and operculum; fin terminating slightly anterior to vertical through base of ultimate anal-fin ray. Small membrane connecting last dorsal- and anal-fin rays to caudal peduncle. First dorsal-fin spine longest, reaching base of seventh spine when depressed. Fourth dorsal-fin spine short, separated by gaps from anterior three and posterior thirteen spines. Low membrane connecting last dorsal-fin spine to first segmented soft ray. First anal-fin spine shorter than second. Membranes of pectoral fin notched; in dorsal portion of fin (dorsal to longest ray), membranes extending from distal tip of one fin ray to distal tip of adjacent fin ray; in ventral portion of fin, membranes extending from distal tip of one fin ray dorsally to point well proximal of distal tip of adjacent fin ray. Ninth pectoral-fin ray (from top of fin, fourth from bottom) longest (broken on left side of holotype), this ray on right side of body reaching posteriorly to vertical through base of third segmented anal-fin ray. Pelvic fin reaching posteriorly to anus when straightened; innermost (third) pelvic soft ray very small, about half length of small (0.5-mm long), pelvic-fin spine. Caudal fin truncate.

Color Prior to Preservation (Fig. 2).—When photographed against a white background (Fig. 2, top), the following visible on the fresh holotype: ground color of body pale grey; side of belly with rectangular-shaped patch of orange-brown pigment with indistinct whitish diagonal bar across center; spinal column with series of eight internal, irregular orange blotches; dorsalmost region of trunk (beneath dorsal fin) and ventralmost region of trunk (above anal fin) each with row of eight to nine orange/brown spots; head grey, densely speckled with fine black melanophores; nape orange-brown, with several yellow blotches; iris orange, grading to yellowish inner ring; yellow bar extending anteroventrally from anteroventral corner of orbit to anterolateral aspect of upper jaw and anterior tip of lower jaw; operculum pale orange, with two yellow-orange spots on lower edge; anterior dorsal finlet (spines I-III) creamy yellow, with four irregular dark brown horizontal cross-bars; second dorsal finlet (spine IV) translucent; remainder of dorsal fin translucent, with two or three irregular rows of round orange-brown spots on both spinous and soft portions; anal fin translucent, with two rows of round orange-brown spots;caudal fin translucent, with row of round, mostly orange spots along dorsal and ventral fin margins and two vertical rows of such spots across posterior third of fin pectoral and pelvic finswithout obvious pigment. When photographed against a black background (Fig. 2, bottom), the following also visible on the fresh holotype: series of long, yellow/white, roughly vertical bars on dorsal fin—one on second finlet (spine IV), three on main portion of spinous dorsal fin, four on soft dorsal fin; bars extending onto dorsal portion of trunk as small white blotches; a series of tiny white spots beneath dorsal-fin base just ventral to white blotches; row of small white spots on trunk just above anal-fin base between dark spots, several extending onto rear of anal fin as short white bars; thin white bar across caudal-fin base; several white spots on outer portion of upper caudal lobe.

Color in Alcohol (Fig. 1).—Trunk pale, central region with midlateral row of four small, rounded blotches of melanophores; additional small blotch present at center of posterior end of caudal peduncle; eight internal blotches of pigment present on dorsal portion of trunk beneath dorsal fin: first blotch beneath origin of main portion of spinous dorsal fin (spine V); last blotch on caudal peduncle; eight similar internal blotches present on ventral portion of trunk above anal fin, posterior markings darker and including a few external melanophores. Head tan, covered entirely with fine melanophores. First dorsal finlet with four dark blotches on membrane between first and second spines; some of this pigment extending onto membrane between second and third spines; second dorsal finlet (spine IV) unpigmented; remainder of fin with two or three rows of small, rounded spots. Anal fin with rounded spots in single row on most of fin, posterior portion of fin with two rows; spots in distal row smaller than those in proximal row. Caudal fin with small pigment blotch on bases of dorsal procurrent rays and another on bases of ventral procurrent rays; remainder of fin mostly pale except with several small, dark markings on dorsal portion of dorsal lobe. Pectoral fin pale, with a few dark spots on membrane between lowermost third and fourth rays. Pelvic fin pale.

Known only from Curaçao, southern Caribbean.

The specific name is in reference to the acronym for the Smithsonian Institution’s Deep Reef Observation Project (DROP), which is treated here as a noun in the genitive case. Haptoclinus dropi is the first of numerous new species that will be described from DROP submersible research in the southern Caribbean.

“Four-fin blenny” is in reference to the configuration of the dorsal fin.

For comparative purposes, counts and measurements of the holotypes of Haptoclinus dropi and Haptoclinus apectolophus (Fig. 3) are given in Table 1, along with distinguishing features of general morphology. Haptoclinus dropi has two fewer dorsal-fin elements than Haptoclinus apectolophus (29 vs. 31), the differences occurring in the third spinous dorsal finlet and soft dorsal fin (III-I-XIII, 12 in Haptoclinus dropi, III-I-XIII, 14 or III-I-XIV, 13 in Haptoclinus apectolophus). Haptoclinus dropi also has one or two fewer soft anal-fin rays (19 vs. 20-21), one fewer pectoral-fin ray (12 vs. 13), and one fewer precaudal vertebra (12 vs. 13). The shape of the first dorsal finlet is different in the two species because of differences in relative sizes of the first three dorsal-fin spines: the first dorsal-fin spine is the longest of the three elements in Haptoclinus dropi (length of first three dorsal spines 18, 7 and 3% SL, respectively); the second dorsal spine is longest in Haptoclinus apectolophus (length of first three dorsal-fin spines 22, 26, and 12% SL, respectively).

Haptoclinus dropi and Haptoclinus apectolophus have very different preserved pigment patterns. In Haptoclinus dropi, the trunk is uniformly pale with a row of external blotches along the lateral midline, a row of mostly internal blotches just beneath the dorsal fin, and a row of mostly internal blotches just above the anal fin. In Haptoclinus apectolophus, there is much more pigment on the ventral portion of the body than there is dorsally, and there are no obvious internal or external blotches of pigment. In Haptoclinus dropi, the first dorsal finlet has four dark blotches, the fourth dorsal-fin spine is unpigmented, and the remainder of the fin is pale with two or three rows of small dark spots. In Haptoclinus apectolophus, the first dorsal finlet is uniformly dark and both the spinous and soft portions of the dorsal fin are peppered with fine melanophores in no apparent pattern. The anal fin is uniformly pale with one or two rows of small dark spots in Haptoclinus dropi. In Haptoclinus apectolophus, the basal three-quarters of that fin are heavily and uniformly pigmented, and the distal quarter is pale. The caudal fin has dark spots dorsally in Haptoclinus dropi, and the pectoral fin has a few dark spots ventrally. In Haptoclinus apectolophus, the caudal and pectoral fins lack melanophores. Haptoclinus dropi differs from Haptoclinus apectolophus in other minor ways: Haptoclinus dropi lacks a fleshy flap on the posterior nostril (vs. fleshly flap extending from anterior margin and covering anterior half of nostril) and has a more slender body (body depth 16.3% SL at the fourth dorsal spine vs. 17.9% SL, depth at caudal peduncle 6.6% SL vs. 9.1% SL).