Vellumnus labyrinthicus ( Miers, 1884 )

Ng, Peter K. L., 2010, On the Planopilumnidae Serène, 1984 (Crustacea: Brachyura: Pseudozioidea), with diagnoses of two new pilumnoid genera for species previously assigned to Planopilumnus Balss, 1933, Zootaxa 2392, pp. 33-61 : 51-53

Vellumnus labyrinthicus ( Miers, 1884)

( Figs. 13A, B , 14A–C , 15 , 16 , 19 B)

Type material. Lectotype (here designated): male (8.5 × 6.8 mm) (NHM 1882.165), Thursday Island, Australia, 3–5 fathoms, coll. HMS Alert. Paralectotypes: 2 females (larger 15.8 × 13.0 mm) (NHM 1882.165), same data as lectotype; 1 male (9.0 × 8.0 mm) (NHM 1882: 93), Port Molle, Australia, 14 fathoms.

Additional material examined. 1 male (9.0 × 8.0 mm) ( ZRC 1983.10.14.1), 1 male, 1 female (9.6 × 8.3 mm) ( ZRC 1983.10.14.2), from sponge, dredged from shell and gravel bottom, west of Pulau Pawai, Singapore, D. S. Johnson, Dec. 1952; 1 ovigerous female (3.6 × 2.0 mm) ( ZRC 1983.10.14.3), between southern islands and Singapore island, 12 Oct. 1953; 1 male (13.9 × 10.0 mm) ( ZRC), Cyrene Reefs, Singapore, on Pavona coral, coll. B. Goh, 15 Aug. 1986; 2 males (14.6 × 12.8 mm, 13.5 × 10.8 mm) ( ZRC 1999.397), dredge, Pulau Semakau, Singapore, coll. P. K. L. Ng, 1991; 1 female ( ZRC 2000.1147), crevices in rock wall, 3 m, northern Pulau Semakau, Singapore, coll. D. Lane, 4 Mar. 2000.

Diagnosis. As for genus.

Remarks. There is some variation in the shape of the G1, with that of the types lacking the small distal flap near the tip, and some specimens having a relatively shorter distal part ( Figs. 15 C–E, 16E–G, I, J). These differences, however, appear not to be significant and the specimens from Australia and Singapore agree in almost all other respects.

Lanchester (1900: 743) reports the species from “5–15 fms., rough bottom”. Johnson (1963) reported it as a commensal on sponges, and they have been found in sponges obtained by dredges, although they have also been found in other habitats. Goh et al. (1990) reported specimens obtained from the bases of living subtidal Pavona corals (Agaraciidae) in Singapore; while others have been obtained from rock crevices.

Figures

FIGURE 15. Vellumnus labyrinthicus (Miers, 1884). A, B, paralectotype male (9.0 × 8.0 mm) (NHM 1882: 93); C – G, 1 male (9.0 × 8.0 mm) (ZRC 1983.10.14.1). A, overall view (carapace partly denuded); B, outer view of left chela; C, left G 1 (ventral view); D, distal part of left G 1 (ventral view); E, distal part of left G 1 (dorsal view); F, left G 2; G, distal part of left G 2. Scales: C, F = 0.5 mm; D, E, G = 0.07 mm.

FIGURE 16. Vellumnus labyrinthicus (Miers, 1884). A – D, male (13.5 × 10.8 mm) (ZRC 1999.397); E – H, lectotype male (8.5 × 6.8 mm) (NHM 1882.165); I, J, male (13.9 × 10.0 mm) (ZRC). A, frontal view showing orbits, epistome, antennule and antenna (denuded); B, right third maxilliped (denuded); C, right side of anterior thoracic sternum (denuded); D, abdomen (denuded); E, left G 1 (ventral view); F, I, distal parts of left G 1 s (ventral views); G, J, distal parts of left G 1 s (dorsal views); H, left G 2. Scales: A, C – E, H = 2.0 mm; B = 1.0 mm; F – H, I, J = 0.5 mm.

FIGURE 19. Position of penis. A, Planopilumnus spongiosus (Nobili, 1905), male (25.6 × 19.0 mm) (ZRC 2009.349), denuded; B, Vellumnus labyrinthicus (Miers, 1884), male (13.5 × 10.8 mm) (ZRC 1999.397), denuded. Abbreviations: cn = condyle of coxa; cx 5 = coxa of fifth ambulatory leg; G 1 = first male pleopod; p = penis; s 5 – s 8 = thoracic sternites 5 to 8, respectively.

FIGURE 13. A, B, Vellumnus labyrinthicus (Miers, 1884), paralectotype female (15.8 × 13.0 mm) (NHM 1882.165 b); C, Colerolumnus fuscus (Balss, 1933), lectotype male (7.3 × 5.4 mm) (ZMB 23359. A, C, dorsal overall views; B, frontal view of carapace.

FIGURE 14. A – C, Vellumnus labyrinthicus (Miers, 1884), male (13.5 × 10.8 mm) (ZRC 1999.397); D, Colerolumnus fuscus (Balss, 1933), lectotype male (7.3 × 5.4 mm) (ZMB 23359). A, D, right side of denuded dorsal surfaces of carapaces; B, anterior thoracic sternum (denuded); left third maxilliped (denuded).