Turleania tenebrosa, Osawa, Masayuki & Fujita, Yoshihisa, 2008

Osawa, Masayuki & Fujita, Yoshihisa, 2008, Two new species of Turleania McLaughlin, 1997 (Crustacea: Decapoda: Anomura: Paguridae) from the Ryukyu Islands, southwestern Japan, and a redescription of T. balli (McLaughlin & Haig, 1996), Zootaxa 1753, pp. 49-68 : 59-67

Turleania tenebrosa n. sp.

( Fig. 7–9 )

Type material. Holotype: male (sl 3.0 mm), “Umagai”, Kume Island, Ryukyu Islands, Japan, 30 m, SCUBA, coll. T. Kawamoto, 13 May 2002 (CMNH-ZC 00932).

Description. Nine pairs of quadriserial gills; no arthrobranchs on third maxillipeds.

Shield ( Fig. 7 A) 1.1 times longer than broad; anterior margin between rostrum and lateral projections concave; anterolateral margins sloping, weakly concave; posterior margin roundly truncate; dorsal surface with few tufts of short setae laterally. Rostrum triangular, overreaching lateral projections, somewhat deflexed ventrally, terminating bluntly. Lateral projections triangular, each with marginal slender spine.

Ocular peduncles ( Fig. 7 A) slender, 0.8 length of shield, each with irregular row of few tufts of short setae on dorsomesial surface; basal part weakly inflated, narrower than corneal width; corneas slightly dilated, corneal width about 0.3 of peduncular length. Ocular acicles elongate, subtriangular, each with small, blunt submarginal spine.

Antennular peduncles ( Fig. 7 A) overreaching distal margins of corneas by 0.7 lengths of ultimate segments. Ultimate segment approximately 2.0 times longer than penultimate segment, widened distally, with long, dorsolateral distal seta and few short setae. Penultimate segment with few short setae. Basal segment with small spine on distal margin of statocyst lobe; ventromesial distal margin also with small blunt spine. Ventral flagellum 0.4–0.5 length of dorsal flagellum.

Antennal peduncles ( Fig. 7 A) overreaching distal margins of corneas by 0.4–0.5 length of ultimate segments, with scattered tufts of short and moderately long setae on all segments. First segment with small laterodistal spine. Second segment with spine at dorsomesial distal angle; dorsolateral distal angle produced, reaching nearly to midlength of fourth segment, terminating in bifid spine. Third segment unarmed at ventrodistal angle. Fourth and fifth segments also unarmed. Antennal acicle weakly arcuate, barely reaching proximal margin of cornea, terminating in small spine; mesial margin with row of few tufts of setae.

Mouthparts not dissected. Third maxilliped ( Fig. 7 D) slender; carpus unarmed; merus with small spine on dorsodistal margin; ischium with well developed crista dentata consisting of row of small corneous-tipped teeth, no accessory tooth; fusion between ischium and basis incomplete; basis with 2 small denticles on mesial margin; coxa with slender spine at distomesial angle; exopod reaching half length of carpus.

Right cheliped ( Fig. 8 A–E) massive, much larger than left. Chela subovate in dorsal view, 2.1 times longer than broad. Dactylus 0.8 length of palm; dorsomesial margin with row of 6 small spines on proximal 0.7; surfaces smooth but with tufts of moderately long setae; cutting edge with blunt calcareous teeth in proximal 0.8, proximal and median teeth prominent, and short row of small corneous teeth distally, terminating in small corneous claw. Palm as long as carpus; dorsal surface convex, with 5 irregular longitudinal rows of tufts of long setae, dorsolateral part bearing small but distinct spines and some very small denticles; dorsolateral margin rounded; dorsomesial margin with irregular row of 8 spines; lateral, mesial and ventral surfaces with longitudinal rows of tufts of short and long setae. Fixed finger with rounded dorsolateral margin; cutting edge with row of blunt calcareous teeth, terminating in small corneous claw. Carpus subtriangular in dorsal view, slightly longer than merus; surfaces with tufts of short and long setae; dorsolateral margin not delimited; dorsomesial margin delimited by row of 5 spines; dorsal surface with row of 3 slightly elevated, short ridges in midline, distal ridge bearing small spine; dorsodistal margin unarmed; lateral, mesial, and ventral surfaces smooth; ventrolateral margin with small distal spine; ventromesial margin unarmed. Merus with row of short ridges bearing tufts of long setae in dorsal midline; dorsodistal margin unarmed; lateral and mesial surfaces with few tufts of setae; ventrolateral margin with 2 subdistal spines; ventromesial margin with distal blunt spine. Ischium with ventromesial margin smooth; surfaces unarmed but with tufts of setae.

Left cheliped ( Fig. 8 F, G, 9A, B) moderately slender. Chela 3.4 times longer than broad. Dactylus 1.2 length of palm; surfaces smooth but with tufts of long setae; cutting edge with row of closely-set, small corneous teeth, terminating in small corneous claw. Palm 0.7 length of carpus; dorsal surface convex, with tufts of short and long setae, weakly elevated in midline; lateral, mesial, and ventral surfaces smooth but with longitudinal rows of tufts of short and long setae. Fixed finger also with tufts of short and long setae; cutting edge with row of small calcareous teeth interspersed with minute corneous teeth, terminating in small corneous claw. Carpus slightly longer than merus, dorsolateral margin delimited by row of 3 spines; dorsomesial margin with only distal spine followed by short ridges; dorsal surface flattish, with tufts of long setae; lateral, mesial, and ventral surfaces with tufts of short and long setae; ventrolateral margin with small distal spine; ventromesial margin unarmed. Merus with row of short ridges bearing tufts of long setae in dorsal midline; dorsodistal margin unarmed; lateral and mesial surfaces with tufts of setae ventrally; ventrolateral margin with 2 subdistal spines; ventromesial margin with small distal spine. Ischium with 5 small denticles on ventromesial margin; surfaces with tufts of setae.

Ambulatory legs ( Fig. 9 C–G) slender, generally similar from right to left, propodi of right pair somewhat longer than left; dorsal and ventral margins of each segment with tufts of short and long setae. Dactyli 1.3–1.4 times longer than propodi, terminating in long corneous claws; dorsal surfaces each with row of slender bristles; ventromesial margins each armed with 7–11 slender corneous spines on distal 0.7; lateral and mesial surfaces unarmed, shallowly concave in midline. Propodi not distinctly tapering distally in lateral view; dorsal surface each with 1–4 bristles on distal half mesially; lateral, mesial, and ventral surfaces nearly smooth; ventrodistal margins each with small corneous spine mesially. Carpi each with small dorsodistal spine; dorsal surfaces each with additional small spine in proximal half mesially (second) or unarmed (third); lateral and mesial surfaces smooth. Meri nearly smooth on lateral and mesial surfaces; ventral surfaces unarmed; ventrolateral distal margins each with very small spine (second) or unarmed (third).

Fourth pereopods ( Fig. 7 E) weakly semichelate, subequal in size, generally similar from right to left. Dactyli relatively broad, terminating in long corneous claws, each bearing tuft of setae on dorsodistal margin; ventral margin with row of small corneous teeth and short setae; preungual process absent. Propodi with tufts of setae on dorsal surface; propodal rasp consisting of single row of small corneous scales. Carpi with sparse tufts of setae on dorsal surface; dorsodistal angle terminating in small blunt spine.

Coxae of fifth pereopods ( Fig. 7 F) unequal; left coxa larger than right, with well developed, stout and flattish sexual tube directed exteriorly and recurved posteriorly (and then somewhat upward in fresh condition; Fig. 10 D), with broad tip obscured by dense fringe of setae, surface with scattered setae; right coxa with gonopore partially masked by fringe of short setae and vas deferens slightly protruded.

Sixth thoracic sternite ( Fig. 7 B) with anterior lobe subovate; anterior margin bearing row of short and long setae but unarmed. Eighth thoracic sternite ( Fig. 7 F) composed of single lobe; ventral surface slightly convex, with short setae.

Pleon with 3 unequally biramous left pleopods, endopods elongate.

Telson ( Fig. 7 C) with weak lateral indentations; posterior lobes distinctly asymmetrical, bordered by narrow chitinous edge on each lateral margin; terminal margins oblique, each with 3 small spines, apex of each lobe terminating in spine.

Color in life ( Fig. 10 D). Shield, posterior carapace, ocular peduncles, and chelipeds whitish, with scattered brown spots. Antennular and antennal peduncles and second to fifth pereopods semitransparent, with scattered brown spots. Shield brown tinged. Cornea greenish brown, with brown spots. Ultimate segment of antennular peduncle with broad brown, interrupted large spots on distal part. Ambulatory legs with white band each on distal parts of propodus and carpus, and subproximal and distal parts of merus. Setae on pereopods whitish.

Etymology. From the Latin adjective, tenebrosus (dark), in reference to the gloomy habitat of the new species.

Habitat. The sole specimen was collected from a large, overhanging wall in “Umagai”, off Kume Island, at a depth of 30 m.

Remarks. As mentioned in the remarks of T. saliens , T. tenebrosa is closer to T. balli than T. saliens in the armatures on the right chela and meri of the second pereopods. Although T. balli and T. tenebrosa are known only from each the holotype, T. balli may differ in having a median spine on the dorsodistal margin of the carpus of the right cheliped (the spine is absent in T. tenebrosa ) and distinct marginal spines on the anterior lobe of the sixth thoracic sternite (no spines are present in the new species). The numbers of corneous spines on the ventral margin of the right third pereopod are also much fewer in T. balli than T. tenebrosa (six versus eleven spines).

The fresh coloration is very similar between T. tenebrosa and T. saliens , but the brown spots on the pereopods are much less numerous in T. tenebrosa than T. saliens . Thus the body represents more whitish coloration in T. tenebrosa .

Figures

FIGURE 7. Turleania tenebrosa n. sp. Holotype male (sl 3.0 mm), CMNH-ZC 0 0 932. A, shield and cephalic appendages, dorsal view (setae omitted from left side); B, sixth thoracic sternite, ventral view; C, telson, dorsal view; D, third maxilliped, proximal segments, lateral view; E, right fourth pereopod, dactylus, propodus, distal part of carpus, lateral view; F, coxae of fifth pereopods and eighth thoracic sternite, ventral view. Scales equal 1.0 mm.

FIGURE 8. Turleania tenebrosa n. sp. Holotype male (sl 3.0 mm), CMNH-ZC 0 0 932. A, right cheliped, mesial view; B, same, lateral view; C, same, chela, dorsal view (setae omitted); D, same, chela and distal part of carpus, ventrolateral view (setae omitted); E, same, carpus, dorsal view (setae omitted); F, left cheliped, chela, dorsal view (setae omitted); G, same, carpus, dorsal view (setae omitted). Scales equal 1.0 mm.

FIGURE 9. Turleania tenebrosa n. sp. Holotype male (sl 3.0 mm), CMNH-ZC 0 0 932. A, left cheliped, mesial view; B, same, lateral view; C, right second pereopod, lateral view; D, same, dactylus and distal part of propodus, mesial view (setae omitted); E, same, carpus, mesial view (setae omitted); F, right third pereopod, lateral view; F, same, dactylus and distal part of propodus, mesial view (setae omitted). Scales equal 1.0 mm.

FIGURE 10. Fresh specimens. Turleania saliens n. sp., holotype male (sl 3.3 mm), CMNH-ZC 0 2187 (A, B); Turleania saliens n. sp., paratype female (sl 2.9 mm), CMNH-ZC 0 2191 (C); Turleania tenebrosa n. sp., holotype male (sl 3.0 mm), CMNH-ZC 0 0 932 (D). A, D, entire specimen, dorsal view; B, same, anterior view; C, carapace and cephalic appendages, dorsal view.