Humphreysella kakuki (Kornicker & Iliffe 2000)

Danielopolina kakuki

ETYMOLOGY.—This species is named in honor of Brian Kakuk, an exceptional cave diver, and Diving Officer at the Caribbean Marine Research Center, who carried out exploration and biological collections from Oven Rock and other caves in the Bahamas.

HOLOTYPE.—USNM 194534, 1 juvenile male on slide and in alcohol.

TYPE LOCALITY.—Sta 95–012, Oven Rock Cave, Great Guana Cay, Exuma Cays, Bahamas.

PARATYPES.—None.

DISTRIBUTION.—Collected only at type locality.

DESCRIPTION (Figures 53–56).—Carapace slightly elongate with fairly straight dorsal margin in vicinity of hinge and also straight margin between anterior and anteroventral processes (Figures 53, 54a). Ventral and posterior margins evenly rounded; valves at greatest width at about midlength and midheight, in vicinity of adductor muscle attachments. Fairly long anterior, anteroventral, and posterodorsal processes with bases just lateral to valve edge, and in similar location on each valve.

Ornamentation (Figures 53, 54a): Surface reticulate with small spine at intersections of walls forming reticulations. Spines also present on 3 processes. Walls of reticulations generally broader in vicinity of intersections then tapering to point midway between intersections so that walls appear as 3-pointed star with spine at center. Reticulations mostly hexagonal but few with 4 or 5 sides. Right valve with few long bristles along dorsal and posterodorsal margins (Figure 54a); both valves with divided bristle on anteroventral margin just ventral to anteroventral process (Figure 54a).

Muscle Attachments: Adductor muscle attachments central in location (Figure 54a); subround with greatest diameter trending towards posterior end of hinge; consisting of several obscure segments. Oval auxiliary muscle scar located anteroventral to adductor muscle attachments (Figure 54a; not shown in Figure 53).

Carapace Size: USNM 194534, length including anterodorsal and posterodorsal processes 0.63 mm; length excluding processes 0.56 mm; height including anteroventral process 0.49 mm; height excluding anteroventral process 0.435 mm.

First Antenna (Figure 54b): 1st joint with 2 ringed bristles (1 lateral, 1 dorsal). 2nd joint with distal medial spines and 1 ringed dorsal bristle. 3rd and 4th joints fused, but place of fusion indicated by thinning in sclerotized dorsal margin and slight decrease in joint width shown by minute step near midlength of ventral margin; 4th joint with short unringed filament-like ventral terminal bristle (bristle broad except for narrow tip). 5th joint with 2 filament-like bristles (1 long (tip missing on illustrated limb), 1 small indistinct). 6th joint bare. 7th joint with 3 bristles (1 short ringed a-bristle, 2 long filament-like b- and c-bristles). 8th joint with 3 terminal bristles (slender dorsal ringed spinous d-bristle, 1 long filament-like e-bristle with widely separated marginal spines, and 1 long filament-like medial f-bristle narrower than e-bristle (tips of e- and f-bristles missing on illustrated limb). Filament-like bristles weakly ringed proximally.

Second Antenna: Protopodite with few long hairs at proximal ventral corner (Figure 54c). Endopodite 3-jointed (Figures 54c, 55): 1st joint with 2 ringed a- and b-bristles; 2nd joint with short ringed dorsal bristle with base near midwidth of lateral side and 3 filament-like ventral bristles (2 long, 1 short); 3rd joint of left limb long slender with 3 bristles or processes at tip (ventral process with 2 or 3 minute terminal papillae; dorsal process short unringed; middle process longer than others and somewhat bristle-like, but at most weakly ringed) (Figures 54c, 55b); 3rd joint of right limb with terminal processes broken off; stem shorter than on left limb (Figure 55a). Exopodite 8-jointed (Figure 54c): 1st joint divided into long proximal and short distal parts; bristles of joints 2–7 long, with natatory hairs; 8th joint with 2 bristles (1 long with natatory hairs, 1 shorter and narrower with small marginal spines); joints 3–7 with indistinct minute spines along distal dorsal margins; only proximal parts shown of long bristles; natatory hairs not shown on long exopodial bristles.

Mandible: Coxale endite with proximal and distal sets of teeth separated by a space (Figure 56a,b); proximal set comprising 4 cusps plus a triangular tooth close to distal set of teeth; surface between cusps and medial and lateral surfaces just proximal to cusps with slender spines; 2 spinous bristles with bases just proximal and another bristle with base just distal to triangular tooth; distal set of teeth consisting of 2 flat teeth, each having 3–5 cusps; 1 slender bristle with base proximal to distal set of teeth. Basale (Figure 56a,c): tooth of endite with 5 triangular cusps (anterior 4 with indistinct minute marginal teeth); posterior edge of endite spinous, with 2 short ringed bristles (distal of these tubular); anterior margin of endite with 1 long ringed bristle near midlength; lateral side of endite with 5 ringed bristles (4 long, 1 short) near midlength and 1 distal bristle ringed except near tip; medial side of basale near dorsal margin with 2 stout ringed bristles; dorsal margin of basale with cluster of spines at apex. Endopodite 3-jointed: 1st joint with lateral spines and dorsal bristle near midlength; 2nd joint spinous with 1 ringed terminal ventral bristle, and 2 ringed dorsal bristles; 3rd joint with dorsal and medial spines and 6 bristles (middle lateral bristle long claw-like) (Figure 56a,d). Rings not shown on all bristles.

Maxilla (Figure 56e–h,k): Endites I to III each with 5 to 8 obscured bristles. Coxale without usual dorsal bristle (probably broken off). Basale with 2 bristles (1 ventral with widely separated long marginal hairs, 1 medial at midwidth). Endopodite: 1st joint with long proximal anterior spines, lateral spines at midlength, 3 long ringed distal anterior bristles, and 3 distal bristles near posterior margin; 2nd joint with 1 anterior stout straight nonarticulated terminal bare claw, 3 slender ringed bristles with bases lateral, and 1 stout proximal claw-like bristle with distal rings and indistinct short marginal spines.

Fifth Limb (Figures 54e,f 56k): Protopodite with 5 bristles (1 tubular). Basale with 6 bristles (1 short claw-like, 2 long plumose, 2 ventral tubular, 1 slender medial proximal). Endopodite with 6 bristles (1 small medial tooth-like, 2 long sclerotized ventral claw-like, 1 ventral tubular, and 2 long plumose). Exopodite 3-jointed: 1st joint with 6 bristles; 2nd joint with 2 ventral bristles at midlength; 3rd joint with 3 bristles (middle bristle about 58% and smallest bristle about 34% of longest bristle). Epipodite obscured.

Sixth Limb (Figures 54g, 56k): Epipodite with 3 groups of plumose bristles (dorsal and ventral group each with 5 bristles, middle group with 4). Precoxale and coxale each with 2 bristles. Basale with 4 bristles. Small endopodite with 2 bristles. Exopodite: joints 1 and 2 fused, with 2 ventral bristles at midlength; 3rd joint with 1 long bristle and 1 small obscured bristle. With appendages in place, tip of 6th limb extends posteriorly slightly past tip of 5th limb.

Seventh Limb: A 7th limb with 2 bristles was observed prior to dissection of specimen (Figure 56i,k), but the limb was not found after specimen was dissected. Whether the limb was lost during the dissection, or was mistakenly observed on the whole specimen prior to dissection, is not known with certainty.

Furca (Figure 54d): Each lamella with 4 claws. Claws 1 and 2 anterior, articulated, and weakly ringed, claw 3 on anteroventral corner, nonarticulated, slight recurved, unringed; claw 4 separated by space from claw 3, nonarticulated, not recurved, triangular, unringed; claws 3 and 4 with minute teeth along posterior edges. Each lamella with medial rows of minute spines, some extending ventrally past edge of lamellae. Stout unpaired process on posterior of body just proximal to lamellae.

Bellonci Organ: Not observed on specimen but could have been obscured.

Lips: Lower lip sclerotized and triangular (Figure 56j). Upper lip with small sclerotized triangular process on each side of anterior of body dorsal to upper lip.

Copulatory Organ: Not observed.

Ganglion (Figure 56i): Oval on each side containing round brown cells (stippled) present posterior to 2nd antenna.