Scandarma papua Naruse & Ng 2020, sp. nov.
Creators: name: Naruse, Tohru
name: Ng, Peter K. L.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Sesarmidae
Scandarma
Scandarma papua

description: Scandarma papua sp. nov.
(Figures 23, 24)
Material examined
Holotype. UF2335, male, 15.8 × 17.8 mm, Louisiade Archipelago, Milne Bay Province, Papua New Guinea, coll. G. Paulay, 4 June 1998.
Others. NHM 1922.11.9.2–5, 1 male, 14.5 × 16.1 mm, 1 female, 11.3 × 12.8 mm, Gabmetzung, Markham River, Huon Gulf, Papua New Guinea, coll. W.J. Potter; RMNH. CRUS.D. 45517, 1 male, 15.4 × 16.7 mm, Hollandia, Papua New Guinea, coll. G. van Hout, May–June 1955.
Diagnosis
Carapace subsquarish, external orbital angle sharp, lateral margins slightly divergent posteriorly; 2 pairs of postfrontal lobes present, lateral lobes slightly exceeding mesial lobes anteriorly in adults (Figure 23 (a)); anterior margins of all lobes relatively close to but never reaching frontal margin in dorsal view. Palm (Figure 23 (b,c)) of male chela swollen; outer surface granulated, granules smaller on lower part, with weak protuberance on proximal part of smooth sloping area around bases of fingers; upper surface (Figure 23 (c)) with 1 straight, longitudinally traversing row of densely packed small granules, and with several short, oblique rows on inner side. Immovable finger (Figure 23 (b)) almost straight, gradually tapering towards tip; occlusal margin lacking marked proximal elevation, lined with small teeth on proximal two-fifths, 1 large bifid tooth submedially, followed distally by 4 or 5 smaller teeth, subdistally with 1 large tooth; lower margin of immovable finger irregularly lined with small teeth. Movable finger (Figure 23 (b)) gently curved, occlusal margin with 2 large teeth on proximal third, followed distally by smaller teeth, and 1 subdistal tooth; inner side of upper surface of movable finger with regular row of flat, rounded granules, granules becoming smaller proximally and distally. Subdistal tooth of immovable finger fitting between tip and subdistal tooth of movable finger when closed. Male pleonal somite 3 widest, somite 4 abruptly narrowed distally, lateral margins of somites 3–5 clearly concave (Figure 24 (a)). G1 (Figure 24 (b)) short, almost straight, stout, narrowed medially, distal end with anterolaterally directed wide corneous process. Vulvae (Figure 24 (c)) located on distal two-fifths of sternite 6, anterior margin adjacent to thoracic sternal suture 5/6 ellipsoidal, rimmed except for posteromesial corner and mesial margin, mesial end of posterior rim produced to wide, short triangular lobe, similar triangular lobe present mesially; sternal vulval cover developed from anterolateral margin, covering vulva except for mesial quarter, cover produced ventrally as trigonal pyramid structure.
Variations
In small individuals (e.g. CW 12.8 mm), all postfrontal lobes are aligned anteriorly; lobes relatively close to but never reaching frontal margin in dorsal view (Figure 17 (c)); there are a clearly discernible epibranchial teeth on the anterolateral margin of the carapace; ambulatory legs are proportionally wider, especially on meri. Small females, however, already have a row of granules on the upper surface of the palm and granules on the upper margin of dactylus, indicating that adult females also have such a row of granules.
Colouration
Live colouration not known.
Distribution
New Guinea: Louisiade Archipelago, Milne Bay Province [type locality]; Gabmetzung, Markham River, Huon Gulf; Jayapura (as Hollandia) (present study).
Etymology
The species name is derived from its known distributional area. The name is used as a noun in apposition.
Remarks
Scandarma papua sp. nov. superficially resembles Sc. gracilipes s.s., but the two species can be distinguished from each other by a number of characters of the male chela, ambulatory legs, vulva, male pleon and G1 (Table 3).
description: Published as part of Naruse, Tohru & Ng, Peter K. L., 2020, Revision of the sesarmid crab genera Labuanium Serène and Soh, 1970, Scandarma Schubart, Liu and Cuesta, 2003 and Namlacium Serène and Soh, 1970 (Crustacea: Decapoda: Brachyura: Sesarmidae), with descriptions of four new genera and two new species, pp. 445-532 in Journal of Natural History (J. Nat. Hist.) (J. Nat. Hist.) 54 (7 - 8) on pages 488-491, DOI: 10.1080/00222933.2020.1763491, http://zenodo.org/record/4609148