Sympagurus villosus, Lemaitre, 1996

Lemaitre, R., 1996, Hermit crabs of the family Parapaguridae (Crustacea: Decapoda: Anomura) from Australia: species of Strobopagurus Lemaitre, 1989, Sympagurus Smith, 1883 and two new genera., Records of the Australian Museum 48 (2), pp. 163-221 : 191-193

Sympagurus villosus n.sp.

Figs 14b,c, 15, 16

Hoiotype. 1 male (SL 13.8 mm), Marion Plateau, Queensland, FRV Soela, sta. 0685-09, 22°57'S, 154°25.5'E , 678-695 m, 18 Nov 1985, NTM Cr 010912.

Paratypes. QUEENSLAND: 1 female (SL 7.2 mm), same sta. data as holotype, NTM Cr 010912 1 male (SL 13.7 mm), off S Stradbroke Is., MV Iron Summer , 27°54'S, l 53°58'E, trawled, 490 m, 30 Nov 1982, colI. S. Hyland , QM W16516 .

Description. First 11 pairs of gills intermediate. Shield (Fig. lSa) approximately as broad as long; dorsal surface weakly calcified, with scattered short setae; rostrum broadly triangular, with short mid-dorsal ridge; anterior margins sinuose; lateral projections broadly rounded; anterolateral margins slightly concave; posterior margin broadly rounded. Anterodistal margin ofbranchiostegite rounded, unarmed, setose.

Ocular peduncles about half length of shield, with row of setae dorsally. Cornea slightly dilated. Ocular acicles subtriangular, terminating in strong spine; separated basally by less than basal width of 1 acicle.

Antennular peduncle long, slender, exceeding distal margin of corneae by half length of penultimate segment. Ultimate segment about twice as long as penultimate segment, with scattered setae. Basal segment with strong ventromesial spine; lateral face with distal subrectangular lobe armed or with 2 to S small spines, and strong spine proximally. Ventral flagellum with 7 to 9 articles.

Antennal peduncle ( Fig. 16d ) exceeding distal margin of cornea by about half length of Sth segment. Fifth segment unarmed, with few setae on lateral and mesial margins. Fourth segment unarmed. Third segment with strong ventromesial distal spine. Second segment with dorsolateral distal angle produced, terminating in multifid spine; mesial margin with spine on dorsodistal angle. First segment unarmed or with 1 or 2 small spines on lateral face; ventromesial angle produced, with S or 6 small spines laterally. Antennal acicles slightly curved outward (in dorsal view), exceeding distal margin of corneae by 0.3 to O.S length of acicle, terminating in strong spine; mesial margin armed with row 6 to 10 spines, densely setose. Flagellum long, exceeding extended right cheliped and ambulatory legs, articles with scattered setae <1 to 2 articles in length.

Mandible with 3-segmented palp. Maxillule ( Fig. 16a,b ) with external lobe of endopod weakly developed, internal lobe with 4 long setae. Maxilla with endopod slightly exceeding distal margin of scaphognathite. First maxilliped with endopod slightly exceeding exopod in distal extension. Second maxilliped without distinguishing characters. Third maxilliped ( Fig. 16c ) with crista dentata of 14 corneous-tipped teeth; coxa and basis each with small mesial tooth. Sternite of 3rd maxillipeds with spine on each side of midline. Epistomial spine straight. Labral spine present.

Chelipeds markedly dissimilar; mesial and ventral surfaces of meri, and all surfaces on carpi and chelae, covered with dense mat of short plumose setae mixed with long simple, bristle-like setae. Right cheliped ( Fig. 14b,c , ISc) with fingers nearly straight, terminating in small corneous claw; cutting edges each with irregularlysized calcareous teeth; dorsal and ventral faces each with distal row of 3 or 4 tufts of setae parallel to cutting edge. Dactyl subequal in length to palm, set at weakly oblique angle to longitudinal axis of palm; mesial face rounded, armed with small, blunt and sharp spines; dorsal and ventral faces unarmed or with scattered small spines. Fixed finger broad at base, dorsal and ventral surfaces similar to dactyl. Palm slightly longer than broad (males) or as long as broad (females), lateral and mesial faces rounded, with irregular rows of small blunt to sharp spines; dorsal surface covered with scattered small spines; ventral surface with scattered small tubercles. Carpus with moderately dense spines or tubercles on dorsal and ventral surfaces; dorsodistal margin unarmed or with 1 or 2 small spines. Merus with scattered small tubercles on lateral face; ventromesial margin with row of small spines. Coxa and ischium each with row of small spines on ventral face; coxa with ventromesial row of setae.

Left cheliped (Fig. ISb) well calcified. Fingers terminating in small corneous claws; dorsal and ventral surfaces unarmed but with several tufts of setae; cutting edge of dactyl with row of minute, fused corneous teeth; cutting edge of fixed finger with row of regularly-spaced, small, evenly-sized teeth. Dactyl longer than palm in length. Palm unarmed on all surfaces. Carpus unarmed except for small dorsodistal spine. Merus unarmed. Ischium with row of small spines on ventral margin. Coxa unarmed but with ventromesial row of setae.

Ambulatory legs (Fig. lSd-f) generally similar from right to left (or right with slightly longer segments than left), at most exceeding extended right cheliped by about O.S length of dactyl; meri, carpi, propodi, and dactyls with numerous stiff setae (more numerous on dactyl). Dactyl approximately 1.4 times as long as propodus, terminating in sharp corneous claw; with dorsal and dorsomesial row of long setae (setae arranged in tufts on proximal two-thirds), and ventromesial row of about 32 corneous spines (most clearly visible in mesial view). Propodus with setae on dorsal and ventral margins. Carpus usually with blunt dorsodistal angle, or at most with small blunt dorsodistal spine, and row of setae dorsally. Merus with setae on dorsal and ventral margins; merus of 2nd pereopods with row of small spines on ventral margin. Ischium of 2nd pereopod with small spines on ventral margin. Coxa of 2nd pereopod with few small spines on ventrodistal margin. Anterior lobe of sternite of 3rd pereopods armed with strong marginal spine, setose (Fig. lSi).

Fourth pereopod (Fig. lSg) semichelate. Dactyl subtriangular, terminating in sharp corneous claw, and ventrolateral row of small corneous spinules. Propodus longer than broad, rasp formed of 2 or 3 irregular rows of conical scales. Merus and carpus with long setae on dorsal margin.

Fifth pereopod (Fig. ISh) semichelate. Propodal rasp extending to mid-length of segment.

Uropods and telson ( Fig. 16 g-i) markedly asymmetrical. Telson with weak transverse suture; posterior lobes separated by shallow cleft, terminal margin of lobes armed with weakly curved corneous spines.

Males with paired 1st and 2nd gonopods; 1st gonopods ( Fig. 16e ) each with moderately concave distal lobe; 2nd gonopods ( Fig. 16f ) each with distal segment nearly flat, anterior face setose distally, and row of short setae on lateral margin medially; basal segment with long setae on posterior face. Females with vestigial 2nd right pleopod.

Habitat and symbiotic associations. Found living In zoanthids ( Epizoanthus sp.).

Distribution. So far known only from Australia. Depth: 490 to 69S m.

Etymology. The specific name is from the Latin villosus , hairy, in reference to the dense setation on the chelipeds and ambulatory legs of this species.

Affinities. This new species superficially resembles Sympagurus trispinosus ( Balss, 1911) , but differs from it in pilosity of the chelipeds and ambulatory legs, and armature of ocular acicles. The pilosity of both right and left chelipeds of S. villosus is very dense, consisting of a mat of short plumose setae mixed with numerous long, simple bristle-like setae ( Fig. 14b,c ). Pilosity of the chelipeds of S. trispinosus is also dense but consists of a mat of only short plumose setae. The ocular acicles are simple on S. villosus , whereas they are multifid on S. trispinosus . Other characters helpful in distinguishing the two species include armature of the ventromesial margin of the dactyls of the ambulatory legs; the dactyl has about 32 spines on S. villosus , and about 18 spines on S. trispinosus . Also helpful is the relative length of the propodi and dactyls of the ambulatory legs; the dactyl is about lA times as long as the propodus on S. villosus , and about 1.7 times as long as the propodus on S. trispinosus . Additionally, the new species lives symbiotically with a zoanthid ( Epizoanthus sp.), whereas S. trispinosus lives with the actinian Stylobates cancrisocia (Carlgren) (see Fautin Dunn et al., 1980).

Figures

Fig. 16. Sympagurus villosus n.sp. a, maxillu1e, internal; b, endopod of same; c, left 3rd maxilliped, internal; d, right antennal peduncle, lateral; e, left male 1st gonopod, mesial; f, left male 2nd gonopod, anterior; g,h, exopod of uropods, dorsal: g, left; h, right; i, telson. Scales = 2 mm (a,d-i d-i), 1 mm (b), and 4 mm (c). (Queensland: a-c, paratype male [SL 13.7 mm], QM W16516; d-i, holotype male [SL 13.8 mm], NTM er 010912).

Fig. 14. Right chelipeds: a, Sympagurus soela n.sp. (2.5x). b,c, S. villosus n.sp.: b, carpus and chela, dorsal (2.8x); c, chela, mesial (2.5x). d,e, Paragiopagurus diogenes (Whitelegge, 1900): d, dorsal (2.7x); e, mesial (l.8 x).