Lissoporcellana monodi Osawa, 2007, n. sp.
Creators: name: Osawa, Masayuki
Publisher: name: Zenodo
Year: 2007
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Porcellanidae
Lissoporcellana
Lissoporcellana monodi

description: Lissoporcellana monodi n. sp.
(Figs. 5, 6)
« Porcellana » sp.— Monod, 1973: 11, figs. 44–51.
Type material. New Caledonia. Ouen Island, Prony Bay, lagoon, St. 110, 22°24’S, 166°47’E, 40 m, coll. B. Richer de Forges/ ORSTOM, male CL 4.1 mm, holotype (MNHN-Ga 5711). Same data as holotype, 1 ovig. female CL 4.6 mm, paratype (MNHN-Ga 5712). Montrouzier Expedition, Passe de Koumac, 25 m, Nephtheidae, 26 Oct. 1993, 1 ovig. female CL 4.6 mm, paratype (MNHN-Ga 5713).
Description. Carapace (Fig. 5 A) weakly or moderately convex dorsally, 1.0–1.1 times as long as broad excluding branchial spines, broadest at bases of posteriormost branchial spines; dorsal surface with numerous, short, faint, transverse striae bearing minute setae on anterior margins. Rostrum (Fig. 5 A) broad, horizontal, produced well beyond eyes; median lobe distinctly exceeding and 4.4–4.7 times as broad as laterals, shallowly concave on midline, divided into 2 sub-lobes by broad U-shaped anterior notch bearing small and minute denticles; lateral lobes narrowly subtriangular, curved mesially in dorsal view, mesial margin crenulated but unarmed. Orbits (Fig. 5 B) moderately deep; supra-orbital margin slightly convex, unarmed; outer orbital angle produced into acute spine; inner orbital margin with small spines. Protogastric ridges moderately or weakly demarcated. Hepatic margins each with strong spine. Cervical grooves weakly demarcated. Branchial margins slightly convex, without distinct longitudinal crest; anterior margin (including anterior end of cervical groove) denticulate or with small spines; median margin with 2 spines, posterior spine larger than anterior; posterior margin and adjacent region with oblique rugae. Cardiac region very weakly striate.
Pterygostomial flaps (Fig. 5 C) entire, with longitudinal rugae, shallowly concave on anterior dorsal part; anterior margin subtriangular with narrowly rounded apex; anterior dorsal margin with 2 or 3 small spines posteriorly.
Third thoracic sternite (Fig. 5 D) depressed medially, trilobate anteriorly; median lobe very broad, strongly convex on anterior margin, with row of setae; lateral lobes narrow, not exceeding median lobe, each with rounded apex. Fourth thoracic sternite with transverse, tuberculate ridge and bearing sparse setae; anterior margin concave.
Telson (Fig. 5 E) composed of 7 plates; proximolateral plates much smaller than others; distal plates broad, terminal margins broadly rounded.
Ocular peduncle (Fig. 5 A) relatively large, with transverse stria on proximal part of dorsal surface; dorsal extension onto cornea roundly subtriangular.
Basal article of antennular peduncle (Fig. 5 F) with transverse ridges on lateromedian ventral surface; lateral margin with row of short setae; anterior lateral part slightly concave; anterior margin armed with 2 subequal-sized spines mesially and smaller spine laterally.
Antennal peduncle (Fig. 5 A, G) moderately short. First article largest, strongly produced forward, broadly in contact with anterior margin of carapace, acutely pointed anteriorly, with longitudinal ridge along ventral margin. Second article with small spine at anterior distal corner and minute spinule at posterior distal corner. Third article subrectangular; anterior margin with small protuberances, distal corners each with minute spinule or unarmed. Fourth article short, with minute spinules on distal margin. Dorsal and ventral surfaces of second to fourth articles faintly striate.
Third maxilliped (Fig. 5 H) with coxa bearing subtriangular projection on distoflexor margin; anterior ventral margin with low, rounded projection bearing minute denticles, distomedian projection incompletely articulated. Basis articulating with ischium, rounded subtriangular. Ischium broad, ovate, transversely rugose on ventral surface, with longitudinal ridge along extensor margin; anterior extensor projection narrow, with rounded apex. Merus with laminate, broad, rounded, subrectangular lobe on ventroflexor margin; ventral surface moderately rugose. Carpus with subtriangular projection on median part of flexor margin and longitudinal ridges on extensor surface. Propodus slender, somewhat tapering distally, with rugae along extensor margin. Dactylus small, subtriangular. Merus to dactylus with long setae on flexor margin. Exopod with proximal article armed with large spine at distomesial margin and 1 or 2 small spines on anterior margin; distal article laminate, robust, reaching midlength of merus, with distal flagellum, proximal part inflated, distal part slender.
Chelipeds (Fig. 6 A–G) moderately unequal in size, subcylindrical, not showing distinct sexual dimorphism. Larger cheliped (Fig. 6 A–D) with ischium crenulate, armed with subdistal small spine on mesial margin. Merus short; dorsal surface transversely rugose, submedian transverse ridge distinct, subacute; dorsoflexor margin crenulate, distally with roundly subrectangular lobe bearing 2 or 3 small spines; dorsodistal margin unarmed; ventral surface transversely rugose, distal flexor margin with strong, slender spine. Carpus 1.4–1.6 times as long as broad, somewhat broadened distally; dorsal surface coved with numerous, delicate, transverse rugae and with shallow sulcus along extensor margin; dorso-extensor margin rounded, unarmed entirely; dorsoflexor margin somewhat concave mesially, crenulate, with 1–3 acute small teeth; dorsodistal margin with broadly rounded lobe on flexor part; ventral surface with transverse rugae, flexor margin slightly crenulate, unarmed. Chela moderately narrow, elongate, 2.2–2.5 times as long as carpus, 2.6–3.4 times as long as high, lying on extensor side, with dactylus opening at oblique angle; extensor margin crested n. sp. on fixed finger, with row of small spines on distal 0.5–0.6 and sparse short setae; fingers crossed distally. Palm inflated dorsoventrally, covered with delicate, short, oblique rugae, no distinct median longitudinal ridge; dorsoflexor margin with longitudinal rugose ridge; dorsodistal flexor margin with low subtriangular projection extending onto dactylus; ventral surface obliquely rugose. Fixed finger with slightly curved distal claw; dorsal surface with scattered very short rugae and small pits; cutting edge with low of small, subacute or rounded teeth and median, low but broad tooth; ventral surface with small pits, proximal flexor part with fringe of dense, soft plumose setae extending onto cutting edge. Dactylus 0.4 of chela length, with moderately curved distal claw; dorsal surface with short rugae and small pits, rounded ridge of rugae present along flexor margin; cutting edge with row of small, rounded teeth and proximal, broad tooth; ventral surface with few small pits, proximal part adjacent to cutting edge with fringe of soft plumes setae. Transverse and oblique rugae on articles with short thin setae on anterior margins.
Smaller cheliped (Fig. 6 E–G) generally similar to larger cheliped; carpus with dorsoflexor margin armed with 4 acute teeth; chela narrower than that of larger; fixed finger not distinctly bifurcate distally; dactylus opening at strong oblique angle, 0.4–0.5 of chela length; cutting edges lacking large teeth.
Ambulatory legs (Fig. 6 H–K) relatively short, with sparse short setae on meri and carpi and scattered tufts of longer setae on propodi and dactyli. Meri elongate, those of first and second legs subequal, longer than third; extensor margin unarmed but slightly crenulate; lateral surface with transverse rugae, distoflexor margin with rounded lobe; mesial surface apparently lacking decalcified part, distoflexor margin unarmed. Carpi with longitudinal and oblique rugae on lateral surface; extensor margin slightly crenulate, with small spinule distally. Propodi 1.3–1.5 times as long as dactyli, 2.8–3.2 times as long as high; lateral surface with short, oblique rugae; extensor margin slightly crenulate but unarmed; flexor margin with 4 slender corneous spines, distal paired spines subequal in size. Dactyli each terminating in moderately or strongly curved, slender claw; flexor margin with 3 corneous spines, proximal 2 spines much smaller than distal, proximal-most spine very small, distal spine with enlarged, produced base, much smaller than terminal claw.
Fifth pereopods slender, chelate; propodus with approximately 10 hooked setae and numerous short simple setae.
Male with pair of developed pleopods modified as gonopods on second abdominal segment (Fig. 5 I, J); protopod naked; endopod spoon-shaped, elongate oval, with numerous marginal setae except for proximal part; exopod small, ovate, naked; pleopods on third to fifth abdominal segments reduced to inconspicuous, low rudiments. Female with paired pleopods on third to fifth abdominal segments; third pair smaller than others, fourth and fifth pairs well developed.
Coloration. No markings remain in the preserved specimens.
Etymology. The specific name is dedicated to Dr. Théodore Monod, for his first recognition of the present unusual species.
Remarks. The new species resembles L. flagellicola Osawa & Fujita, 2005 and L. quadrilobata (Miers, 1884) in having the median lobe of the rostrum with a distinct notch on the anterior margin; median branchial margins each armed with more than two spines; and carpi of the chelipeds being unarmed on the dorso-extensor margins. However, L. monodi n. sp. is distinguished from these two congeners by the branchial margin of the carapace being more strongly convex, lateral lobes of the rostrum being much narrower than the median lobe and unarmed on the mesial margin, and basal article of the antennular peduncle with an anterolateral spine. Lissoporcellana monodi n. sp. further differs from L. flagellicola in having much more slender terminal claw each on the dactyli of the ambulatory legs. Although similar shapes of the dactyli are seen in L. quadrilobata, this species is easily distinguishable from the new species and L. flagellicola by the elongate carapace (1.2 times as long as broad in L. quadrilobata, but 1.0–1.1 times as long in L. monodi n. sp. and L. flagellicola).
Haig (1978) mentioned that Monod’s (1973) “« Porcellana » sp.” was perhaps identical with L. nakasonei (Miyake, 1978) (as L. maculata (Miyake, 1957)). However, as Osawa (1998b) pointed out, Monod’s (1973) specimen from New Caledonia probably belong to another, perhaps undescribed species. Monod’s (1973) figures (figs. 44–51) show that his specimen agrees well with the diagnostic characters of the present new species. There is no doubt that his specimen belongs to L. monodi n. sp.
Distribution. At present, known only from New Caledonia, 25– 40 m. A paratype was collected from a species of Nephtheidae (Alcyonacea, Octocorallia).
description: Published as part of Osawa, Masayuki, 2007, Porcellanidae (Crustacea: Decapoda: Anomura) from New Caledonia and the Loyalty Islands, pp. 1-49 in Zootaxa 1548 on pages 15-19, DOI: 10.5281/zenodo.178040