Paradynomeninae

Guinot, Danièle, 2008, A re-evaluation of the Dynomenidae Ortmann, 1892 (Crustacea, Decapoda, Brachyura, Podotremata), with the recognition of four subfamilies, Zootaxa 1850, pp. 1-26 : 11-13

Paradynomeninae n. subfam.

( Figures 1 B, E, 4D, 5M, N)

Type genus. Paradynomene Sakai, 1963 (type species by monotypy: P. tuberculata Sakai, 1963 ).

Diagnosis. Body thick, uniformly covered with tubercles, granules and/or spines. Carapace longer than wide or as long as wide, sometimes slightly wider than long, subquadrangular, may be suboval; dorsal surface convex, distinctly areolated, often with swellings or bosses, usually densely ornamented. Cervical groove entire, not reaching lateral carapace margin; frontal, cervical, branchial, branchiocardiac grooves pronounced. Anterolateral margins subparallel or slightly convex, distinctly joining corners of buccal cavity, armed with 4– 6 irregular salient teeth or prominences. Posterolateral margin with produced and elongated subdistal tooth; a tooth present posteriorly, variously salient. Posterior region of carapace recessed; posterior margin strongly concave. Frontal margin usually distinctly projecting, tridentate, rarely bidentate; supraorbital margin with small tubercles, notch; infraorbital margin with granules, teeth, notches. Orbits oblique, clearly visible from dorsal view; eyestalks short. Antenna with suboval urinal article, beaked medially; second article with firmly fixed exopod. Proepistome wide. Presence of a produced ventral anterior area, forming “face” with projecting front, inflated subhepatic, pterygostomial portions and merus of mxp3; when retracted, chelipeds with fingers resting next to mxp3 exopod and flat portion of pterygostomial region. Anterior border of endostome forming raised wall, laterally notched by exhalant orifices. Mxp3 operculiform, sharply angled; basis long, separated from ischium by incomplete suture; ischium, merus almost at right angles, ischium narrow basally, merus trigonal, laterally extended. Pleural line partially indistinct; branchiostegite of normal texture. Thoracic sternum narrow, completely covered laterally by abdomen, except for external portion of episternite 5 and small extension of episternite 6 which remain exposed when abdomen closed; external margin of abdomen close to P2, P3 coxae. Sternites 1 and 2 fused into triangular or cordiform shield; sternite 3 represented by short, narrow band at base of shield, delimited posteriorly by change in level and denticulate crest; no other marks on successive sternites. Most part of sternites 4–8 fused into single wide plate; sternite 8 tilted. Sterno-coxal depressions deep. Female sutures 7/8 ending well apart, mostly hidden by internal border of P3 sterno-coxal depression; spermathecal aperture extremely small, opening slightly behind level of coxal female gonopore. Sterno-abdominal depression moderately excavated, with oblique slopes in males, and with flat median floor. Male abdomen with all somites free, wide, long, extending onto sternum up to base of anterior shield; first somite dorsal, in prolongation of carapace, proximal portion inserted into concave posterior margin of carapace; somite 2 slightly narrower, other abdominal somites wider, increasing in width; telson broadly triangular. In males rudimentary biramous pleopods on somites 3–5. Male uropod moderately developed, occupying about half length of lateral margin of abdominal somite 6, slightly mobile. Movements of abdomen restricted in both sexes because of sets of granules on P2, to a lesser extent on P3 coxae. Chelipeds equal, more robust than P2–P4; fingers closed for about half or to most of their length, dactylus not curved or moderately curved; fixed finger almost straight. P2 to P4 relatively stout, ornamented with prominences, blunt teeth or spines; dactyli with 4 or 5 spines on lower margins. P5 reduced, sexually dimorphic; basis-ischium fused to merus, forming a single article; rudimentary ending (dactylus as long as propodal extension) forming a subchelate mechanism in females only. Coxa of P5 modified in males to enclose penis, extension narrow, elongated. Pl1 vestigial in females. Gonopod 1 stout, forming semi-rolled tube, with apical oval lobe surrounded by dense fringe of long setae. G2 needle-like, with linear row of tiny distal spines.

Remarks. The. subfamily is monotypic. Paradynomene , which until recently was monospecific, now comprises six extant species ( McLay & Ng 2004; Table 1).

Figures

FIGURE 1. Representative species of the four subfamilies of Dynomenidae, overall view. A, Acanthodromiinae n. subfam.: Acanthodromia margarita (Alcock, 1899), Balicasag Island, Panglao, Bohol, Visayas, Philippines (ZRC) (see McLay & Ng 2005: 18); B, Paradynomeninae n. subfam.: Paradynomene tuberculata Sakai, 1963, Balicasag Island, Panglao, Bohol, Visayas, Philippines (ZRC) (see McLay & Ng 2004: 4); C, Metadynomeninae n. subfam.: Metadynomene tanensis (Yokoya, 1933) with its undulating tomentum, Balicasag Island, Panglao, Bohol, Visayas, Philippines (ZRC) (see McLay & Ng 2005: 25); D, Dynomeninae Ortmann, 1892: Hirsutodynomene vespertilio McLay & Ng, 2005, Balicasag Island, Panglao, Bohol, Visayas, Philippines (ZRC) (see McLay & Ng 2005: 21). E, Paradynomene tuberculata Sakai, 1963, New Caledonia, frontal view showing the characteristic “ face ” (ZRC). (All photographs courtesy of P. K. L. Ng).