Anoplonida patae, Macpherson & Baba, 2006

Macpherson, Enrique & Baba, Keiji, 2006, New species and records of small galatheids (Crustacea, Decapoda, Galatheidae) from the Southwest and Central Pacific Ocean, Zoosystema 28 (2), pp. 443-456 : 445-448

Anoplonida patae n. sp.

( Figs 1 ; 2 )

TYPE MATERIAL. — Holotype: Tonga. BORDAU 2, stn CP 1572, 19°42.31’S, 174°31.35’W, 391-402 m, 11.VI.2000, ♂ 4.7 mm (MNHN-Ga 5299).

Paratypes: Fiji. BORDAU 1, stn CP 1475, 19°40.70’S, 178°11.15’W, 321-424 m, 8.III.1999, 2 ovig. ♀♀ 4.9- 5.2 mm (MNHN-Ga 5300).— Stn CP 1476, 19°41.50’S, 178°11.30’W, 310-420 m, 8.III.1999, 1 ovig. ♀ 5.4 mm (MNHN-Ga 5301).

Tonga. BORDAU 2, stn CP 1525, 21°17.25’S, 174°59.37’W, 349-351 m, 2. VI.2000, 1 ovig. ♀ 4.3 mm (MNHN-Ga 5302). — Stn CP 1572, 19°42.31’S, 174°31.35’W, 391-402 m, 11. VI.2000, 1 ♀ 4.9 mm (MNHN-Ga 5303).

ETYMOLOGY. — The species is named in honor of Patsy A. McLaughlin, our dear colleague and eminent decapod crustacean systematist.

DISTRIBUTION. — Tonga and Fiji, 310- 424 m.

DESCRIPTION

Carapace 0.8 times longer than broad, greatest breadth measured behind end of anterior cervical groove; dorsal surface covered with numerous striae, mostly interrupted, with or without a number of tubercles on anterior branchial region. Gastric region posteriorly bordered by distinct cervical groove; epigastric transverse ridge distinctly elevated from level of rostrum, bearing pair of small, blunt spines; gastric process absent. Cardiac process well elevated, rounded in profile anteriorly. Anterior part of branchio-cardiac boundary elevated but much lower than cardiac process. Lateral margins somewhat convex, convergent behind anterior cervical groove; anterolateral spine stout, horizontal, directed straight forward, ending in blunt tip, overreaching supraocular spines, terminating in mid-length of rostral spine; blunt short spine between anterolateral spine and end of anterior cervical groove; four short, blunt spines or processes on anterior branchial region.

Rostrum anteriorly narrowed; dorsal surface with low median ridge continued on to rostral spine; rostral spine straight, nearly horizontal or directed somewhat dorsally, laterally ridged, reaching end of cornea, length 0.3 times that of carapace. Supraocular spines very short, as illustrated.

Sternal plastron 3/4 as long as broad, sternites successively broader posteriorly, with interrupted ridges in moderate density; anterior margin of sternite 4 concave, contiguous with entire posterior margin of sternite 3.

Abdominal segments 2-4 with two pairs of small blunt spines on each tergite, lateral pair obsolescent. Telson subdivided into 12 platelets, length 0.64 breadth.

Cornea strongly dilated; long eyelashes reaching end of cornea.

Antennules having basal article somewhat granulate, mesial margin with few denticles on distal half, distally ending in blunt small spine accompanying few small spines dorsal to it; distolateral margin ending in short spine distinctly larger than distomesial spine. Segment 1 of antennal peduncle ventrally with depressed distomesial process ending in acute spine; article 2 with acute distomesial spine and blunt, mesio-laterally compressed distolateral process; flagellum reaching mid-length of P1 merus in male, overreaching P 1 in female.

Mxp 3 ischium 1.5 times longer than merus when measured on mid-lateral line, dorsoventrally depressed and thin, mesial ridge with 11-13 tubercle-like denticles rather distant from one another; flexor margin with blunt short distal spine. Merus short relative to length; flexor margin with one or two median spines proximally followed by a number of tubercles; extensor margin with small distal spine.

Male P1 9.7 times longer than carapace, remarkably slender. Merus longer and broader than carpus, and much more granulate and even tuberculate; mesially with two spines (one distal to and one proximal to mid-length). Carpus unarmed, c. 30 times longer than broad (breadth measured at midlength). Palm unarmed, much narrower than, and 1.6 times longer than carpus, 14 times longer than movable finger; length 70 times width. Fingers very short, distally sharp and incurved, crossing each other when closed; opposable margins with small denticles, without gaping.

Female P1 1.5-2.0 times longer than carapace, short and broad relative to male P1; surface sparsely tuberculate. Merus 1.4-1.9 times longer than carpus, terminally bearing three blunt spines (mesial, middorsal, lateral), distomesial largest. Carpus twice as long as broad, bearing three mesial spines, proximal-most smaller and slightly dorsal in position. Palm narrower than carpus, 2.4 times longer than broad; length 1.4 times that of movable finger. Fingers not gaping, distally ending in sharp, incurved spines.

P2-P4 relatively slender, sparsely tuberculate, with sparse iridescent setae along extensor margin of merus. Male P2 slightly overreaching mid-length of P1 merus, female P2 reaching distal end of P1 palm. Meri successively shorter posteriorly; extensor margin with row of small spines, distal-most terminal, distinct on P2 and P3, very small on P4; flexor margin with row of small spines, terminal spine distinct on P2, distinct or obsolescent on P3, nearly absent on P4. Carpus with four to six small, blunt extensor marginal spines subparalleling to row of three smaller spines on lateral surface. Propodus 1.3-1.4 (male holotype) or 1.1- 1.2 (female paratypes) times longer than dactylus; extensor margin with row of small spines; flexor margin with slender, movable distal spine. Dactylus slender, somewhat curved, extensor margin crenulate, with stiff setae in moderate density on distal half, plumose setae on proximal half; flexor margin smooth, with two to five seta-like movable spines on P2, zero to two similar spines on P3, zero or one on P4.

Male P5 chela without brush of plumose setae on flexor face, very setose on fingers and distal portion of propodus (relatively long setae); movable finger more than half length of palm. Female P5 with much shorter, less numerous setae.

Male G1 absent.

REMARKS

The new species cannot be placed in any genera lacking male G1. Among the genera proposed by Baba & de Saint Laurent (1996), Anoplonida may be the one that could be considered for this new species. However comparison of A. patae n. sp. with the two known species of Anoplonida (see Baba & de Saint Laurent 1996) shows that the well developed cardiac process, pairs of both epigastric spines and postcervical processes, Mxp 3 merus bearing one or two flexor marginal spines, and the antennular basal article bearing a single distolateral spine, all displayed by the new species, do not fit the diagnosis of the genus. In other essential characters the three species are very similar. We propose here to emend the diagnosis of Anoplonida to accommodate these three species.

The male P1 of the new species is nearly the same as that of A. cracentis Baba & de Saint Laurent, 1996 . In the latter species, however, the female P1 was lacking. The female P1 of A. patae n. sp. is very much like that of A. inermis ( Baba, 1994) . The male P1 of A. inermis is noted to be the same as the female P 1 in small specimens, but in large specimens it grows up to much greater length. Sexual dimorphism in P1 as shown by Anoplonida is unique among the genera of Galatheidae .

EMENDED DIAGNOSIS OF GENUS ANOPLONIDA Carapace with distinct, uninterrupted, transverse ridges, without gastric process; cardiac process and postcervical processes present or absent. Rostrum relatively narrow, rostral spine stout, laterally ridged, close to supraocular spines. Abdominal segments 2-3 each with two pairs of spines, lateral pair obsolescent. Sternite 4 with remarkably broad, concave anterior margin, contiguous with whole posterior margin of preceding sternite. Telsonal subdivision complete. Ocular peduncles dorso-ventrally flattened, cornea dilated. Antennular basal article with one or two distolateral spines. Antennal flagellum more than twice as long as carapace. Endopods of Mxp 3 with three distal articles reduced in size, merus with one or two median spines on flexor margin and distal spine on extensor margin. P1 much more slender and longer in male than in female. P2-4 dactyli slender, nearly entire on flexor margin. Chelae of P5 with setae moderate in density on flexor face, without brush of plumose setae, fingers more setose, setae simple, not ribbon-like.

Figures

FIG. 1. — Anoplonida patae n. sp., ♂ holotype, Tonga (MNHN-Ga 5299): A, carapace and abdomen, dorsal; B, same, lateral. Scale bar: 1 mm.

FIG. 2. — Anoplonida patae n. sp., Tonga: A-F, H-L, ♂ holotype (MNHN-Ga 5299); G, ♀ paratype 4.9 mm (MNHN-Ga 5303); A, sternal plastron; B, telson; C, left antennule, antenna, eye and anterior part of pterygostomian flap, ventral; D, endopod of left Mxp 3, lateral; E, right P1, dorsal; F, same, distal part of chela; G, right P1, dorsal; H, left P2, lateral; I, same, distal part, setae omitted; J, left P3, setae omitted, lateral; K, left P4, setae omitted, lateral; L, right P5, distal part, extensor side. Scale bars: 1 mm.