Planopilumnus spongiosus Nobili 1905

Planopilumnus spongiosus (Nobili, 1905)

(Figs. 1–4, 8 A, B, 9A, 10A, B, 19A)

Pilumnus spongiosus Nobili, 1905: 406; 1906: 280, pl. 10 fig. 6. — Klunzinger 1913: 265.

Planopilumnus spongiosus – Balss 1933: 40, text fig. 5A. — Serène 1968: 86. — Ng et al. 2008: 180.

Material examined. Syntypes: 1 male (9.4 × 7.1 mm), 1 broken male, 2 females (18.2 × 13.3 mm, 13.8 × 9.8 mm) (MNHN), Perim, Strait of Mandeb, southern Red Sea, off Yemen, coll. P. Jousseaume; 1 male (25.6 × 19.0 mm), 1 female (21.0 × 15.8 mm), 1 ovigerous female (16.7 × 12.0 mm) (ZRC 2009.349), low intertidal zone, Nosy Be, Madagascar, coll. A. Crosnier.

Diagnosis. As for genus.

Remarks. Nobili (1905) described P. spongiosus from Périm, a volcanic island in the Strait of Mandeb in the Red Sea. He did not state how many specimens he had, providing measurements only for a 18.0 × 15.0 mm male. Nobili (1906) later stated he had four males and three females. All should be regarded as syntypes. Three of these syntypes are in the MNHN, all in relatively poor condition. The solitary male specimen is badly damaged and its male abdomen and gonopods are missing. It is preferred not to designate a lectotype from this series at this time on the hope that the condition of the remaining syntypes, if found, are in better condition.

There is some variation in the form of the anterolateral teeth. The first anterolateral tooth varies from triangular (Figs. 1 A, 2C, 8A) to subtruncate (Figs. 2 A, B, 8B), and this does not appear to be associated with size or sex, at least on the basis of the limited material on hand. The ambulatory legs (notably the merus) are also proportionately slightly longer in males (Fig. 2 B) than females (Fig. 2 C).

Ng & Tan (1984) showed that Rathbun’s (1923: 111) record of “ Planopilumnus spongiosus ” from Victoria, Australia was actually Globopilumnus multituberosus Garth & Kim, 1983 (Oziidae). This species was subsequently synonymised with Pilumnus laciniatus Sakai, 1980, and transferred to Globopilumnus (Ng 1992). Ng et al. (2001) argued that Eupilumnus Kossmann, 1877, is a senior synonym of Globopilumnus Balss, 1933.