Oncopagurus conicus, Lemaitre, 2006
Lemaitre, Rafael, 2006, Two new species of Parapaguridae (Crustacea, Decapoda, Anomura, Paguroidea) with subconical corneas, and new data on biology of some rare species, Zoosystema 28 (2), pp. 517-532: 519-524
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Oncopagurus conicus n. sp.
TYPE MATERIAL. — Holotype: New Caledonia. HALI- PRO 1, stn C 858, 21°42’S, 166°41’E, 1000-1120 m, 20.III.1994, ♂ 2.0 mm (MNHN-Pg 7612). GoogleMaps
Paratypes: same stn as holotype, 2 ♀♀ 2.0, 2.4 mm (MNHN-Pg 7613). — BIOGEOCAL, stn CP 214, 22°43’09’S, 166°27’19’E, 1590-1665 m, 9.IV.1987, 1 ♂ 2.1 mm, 1 ♀ 1.8 mm, 1 ovig. ♀ 2.1 mm (MNHN- Pg 7614).
ETYMOLOGY. — The specific epithet is from the Greek konikos, meaning cone-like, and refers to the shape of the corneas in this species.
DISTRIBUTION. — So far known only from the New Caledonian region; 1000 to 1665 m.
Gills biserial ( Fig. 1A View FIG ). Shield ( Fig. 1B, E View FIG ) longer than broad; dorsal surface weakly calcified medially and sometimes also anteriorly, with scattered short setae; rostrum broadly rounded, weakly produced, with short mid-dorsal ridge; anterior margins weakly concave; lateral projections subtriangular, terminating in small spine; anterolateral margins sloping; posterior margin broadly rounded; ventrolateral margins of shield without spine. Anterodistal margin of branchiostegite rounded, unarmed, setose.
Ocular peduncles ( Fig. 1C View FIG ) more than half length of shield, diminishing in width distally, somewhat inflated ventroproximally; with longitudinal row of long setae dorsally; ventroproximal surface weakly calcified.Cornea reduced, subconical, usually ending sharply. Ocular acicles subtriangular, terminating in strong spine; separated basally by about basal width of one acicle.
Antennular peduncle long, slender, exceeding distal margin of cornea by at least 0.25 length of penultimate segment. Ultimate segment nearly twice as long as penultimate segment, with scattered setae. Basal segment with strong ventromesial spine; lateral face with distal subrectangular unarmed except for setae, and strong spine proximally.Ventral flagellum with four or five articles.
Antennal peduncle ( Fig. 1F View FIG ) exceeding distal margin of cornea by about 0.2 length of fifth segment. Fifth segment unarmed, but with scattered setae.Fourth segment unarmed.Third segment with strong ventromesial distal spine. Second segment with dorsolateral distal angle produced, terminating in strong, simple spine; mesial margin with spine on dorsodistal angle. First segment with lateral face unarmed or with small spine; ventromesial angle produced, with two or three small blunt spines laterally. Antennal acicle nearly straight (in dorsal view), not reaching distal margin of cornea, terminating in strong spine; mesial margin armed with two to five small spines, setose. Flagellum long, slightly exceeding extended right cheliped, articles with setae <1-3 flagellar articles in length.
Mandible ( Fig. 2A View FIG ) with three-segmented palp; cutting edge calcified, with small corneous tooth medially; molar process with small corneous tooth medially. Maxillule ( Fig. 2B View FIG ) with external lobe of endopod slender, moderately developed, not recurved, internal lobe with long, terminal seta. Maxilla ( Fig. 2C View FIG ) with endopod exceeding distal margin of scaphognathite.First maxilliped ( Fig. 2D View FIG ) with endopod exceeding exopod in distal extension. Second maxilliped ( Fig. 2E View FIG ) without distinguishing characters. Third maxilliped ( Fig. 2F, G View FIG ) with merus to dactyl each distinctly longer than broad, ischium about twice as long as broad; crista dentata with about nine corneous-tipped teeth; basis with mesial spine; coxa lacking spine. Sternite of third maxillipeds with small spine on each side of midline. Epistomial spine slender, strongly curved upward ( Fig. 1D View FIG ).
Chelipeds markedly dissimilar. Right cheliped ( Fig. 1 View FIG G-I) relatively slender, with moderately dense setae on dorsal surfaces of carpus and chela. Fingers nearly straight, terminating in small, usually blunt corneous claw; cutting edges with two (dactyl) or three (fixed finger) large calcareous teeth. Dactyl about as long as mesial margin of palm, set at weak oblique angle to longitudinal axis of palm; mesial margin broadly curved, well defined by row of blunt or sharp spines diminishing in size distally; dorsal face with scattered small tubercles, ventral face smooth, ventromesial face concave.Fixed finger broad at base, dorsal and ventral faces with scattered small spines or tubercles. Palm longer than broad, lateral surface rounded, sometimes with dorsolateral margins weakly delimited by row of small spines; mesial face rounded, with scattered small tubercles; dorsomesial margin delimited by row of small blunt or sharp spines; dorsal surface with well spaced small spines or tubercles; ventral surface with scattered small tubercles. Carpus with dorsolateral margin rounded; dorsal surface with well spaced small spines or tubercles; ventromesial margin with row of spines; ventral face with scattered small tubercles. Merus with setae mostly dorsally and on mesial and ventral surfaces; ventromesial margin with row of spines. Ischium and coxa unarmed, but with ventromesial row of setae.
Left cheliped ( Fig. 1J View FIG ) sometimes weakly calcified medially on merus and carpus. Fingers terminating in small corneous claw; dorsal and ventral surfaces unarmed except for scattered tufts of setae; cutting edge of dactyl with row of minute, fused corneous teeth; cutting edge of fixed finger with row of well spaced small corneous teeth. Dactyl slightly shorter than mesial margin of palm in length. Palm unarmed except for dorsomesial and dorsolateral setae; ventral face smooth. Carpus with dorsodistal spine; dorsal margin with long setae; ventral face smooth. Merus with long setae on dorsal margin; ventral face smooth. Ischium and coxa unarmed, but with ventromesial row of setae.
Ambulatory legs ( Fig. 3 View FIG A-D) or second and third pereopods similar right from left except for longer meri on right; exceeding extended right cheliped by about 0.20 or less length of dactyls. Dactyl broadly curved, about twice as long as propodus, and terminating in sharp corneous claw; with dorsal and dorsomesial distal rows of long setae, and ventromesial row of about four to seven slender, corneous spines. Propodus with row of setae on dorsal margin, and scattered setae on ventral margin. Carpus with small dorsodistal spine, and long setae dorsally. Merus and ischium unarmed except for setae on dorsal and ventral margins. Coxa with ventromesial row of setae. Anterior lobe of sternite XII (third pereopods, Fig. 4A, B View FIG ) subsemicircular, setose, with distinct spine.
Fourth pereopod ( Fig. 3E View FIG ) semichelate. Dactyl terminating in sharp corneous claw; with ventrolateral row of small corneous spinules. Propodus longer than broad, rasp with one row of rounded scales at least distally. Carpus with long setae on dorsal margin. Merus with rows of long setae on dorsal and ventral margins.
Fifth pereopod ( Fig. 3F View FIG ) semichelate. Propodal rasp extending to mid-length of segment.
Uropods and telson symmetrical or nearly so ( Fig. 4C View FIG ). Telson lacking transverse suture; dorsal surface with scattered short setae; lateral margins with long setae distally; posterior margin separated into shallow or obsolete U-shaped cleft into rounded projections, each armed with about four to seven corneous spines, some often ventrally curved.
Male first gonopod ( Fig. 4D View FIG ) with weakly concave distal lobe; second gonopod ( Fig. 4E View FIG ) lacking rudimentary exopod, distal segment with row of short bristles on lateral margin medially, and long setae on distomesial face. Female with short, uniramous, unsegmented second right pleopod.
Live coloration unknown.
An important character to consider in separating this new Oncopagurus species as well as other congeners from those of other parapagurid genera, is the presence of an upwardly curved epistomial spine ( Fig. 1D View FIG ). This new species is the second found in the genus Oncopagurus to have reduced, subconical corneas, the other is O. minutus . The two can be separated using subtle characters. In the new species the corneas terminate sharply ( Fig. 1C View FIG ) whereas in O. minutus they terminate bluntly; the antennal acicles are armed mesially with weak spines ( Fig. 1B, E View FIG ), whereas in O. minutus the spines are strong; the dactyls of the ambulatory legs are armed on the ventral margins with long spinules ( Fig. 3B, D View FIG ), whereas in O. minutus the spinules are short; the uropods and telson are symmetrical or nearly so ( Fig. 4C View FIG ), whereas in O. minutus they are markedly asymmetrical.
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