Aniptumnus quadridentatus (De Man, 1895 )

Trivedi, Jigneshkumar, Mitra, Santanu, Patel, Pooja, Maheta, Niketa, Patel, Krupal & Ng, Peter K. L., 2021, On the Indian species of Eurycarcinus A. Milne-Edwards, 1867, Heteropanope Stimpson, 1858, and Pilumnopeus A. Milne-Edwards, 1867 (Decapoda: Brachyura: Pilumnidae), Nauplius (e 2021004) 29, pp. 1-18 : 12-15

Aniptumnus quadridentatus (De Man, 1895)

( Figs. 7 , 8 , 10G–I )

Pilumnus seminudus — De Man, 1887: 65 [not Pilumnus seminudus Miers, 1884 = Glabropilumnus seminudus (Miers, 1884) ].

Pilumnus quadridentatus De Man, 1895: 537 , fig. 6; Nobili, 1906: 278.

Parapilumnus quadridentatus Balss, 1933: 39 (list); Tan and Ng, 1994: 84 (list).

Heteropanope neolaevis Deb, 1995: 220 ; 1999: 374, figs. 3, 4; Ng et al., 2018: 475, 481–482; Trivedi et al., 2018: 59 (list).

Aniptumnus quadridentatus — Ng, 2002: 213, figs. 1, 2; Ng and Clark, 2008: figs. 13–18; Ng et al., 2008: 140 (list).

Type locality. Pontianak , West Kalimantan , Indonesia.

Material examined. Lectotype, male (CW 13.9 mm; CL 9.6 mm), ZSI-C1503/2, Matla River, Gangetic Delta, West Bengal State, India , December 1916, coll. S.W. Kemp. Paralectotypes, 4 males (CW 8.0– 9.3 mm; CL 5.8–6.5 mm), same data as holotype .

Remarks. Ng et al. (2018: 481–482) clarified the date of publication for Heteropanope neolaevis , noting that the correct spelling of the name and citation should be Heteropanope neolaevis Deb, 1995

Deb (1995: 220) listed “50 examples” of this species (as H. neolaevis ) from an estuarine area in the Matla River, Gangetic Delta, West Bengal State, India, and no types were designated. Deb (1999: 374) noted that she had “Several (about 50) specimens including holotype and paratypes from Gangetic delta, collected by S. W. Kemp, Z.S.I. Regd. No. C1503/2”. She did not specify the sex or size of the holotype. In the ZSI, there is one male specimen labeled as holotype which has the same data as indicated by Deb (1999) and is here recognized as the lectotype since no holotype was noted in the original paper ( Deb, 1995).

Ng et al. (2018: 475) commented that the species is neither Heteropanope nor Pilumnopeus or Benthopanope , and the G1 figured ( Deb, 1999: fig. 4) was unusual, being short and stout with the tip rounded. The lectotype and paralectotypes of H. neolaevis were examined and the Heteropanope neolaevis of Deb is here identified as Aniptumnus quadridentatus (De Man 1895) . De Man (1895) described Pilumnus quadridentatus from a good series of specimens from the port of Pontianak, West Borneo, Indonesia. He also referred a specimen earlier obtained from Mergui (De Man, 1887) to this species. Nobili (1906) reported the species from Djibouti in the Red Sea, but his specimen should be re-examined in order to confirm its identification. Balss (1933) first referred it to Parapilumnus De Man, 1895 , but Ng (2002) reviewed the status of Parapilumnus and showed that this genus was actually not a pilumnid but an acidopsid. Ng (2002) selected a lectotype for P. quadridentatus and made it the type for a new genus, Aniptumnus , characterized by its subtruncate G1 tip, presence of sharp granules on the ventral margin of the basis-ischium and merus of the fourth ambulatory leg.

The types of H.neolaevis agree with the descriptions and figures of A. quadridentatus by De Man (1895), Ng (2002), and Ng and Clark (2008) and are considered conspecific. The carapace, cheliped and ambulatory leg characters all agree ( Figs. 7A, b , 8A ). The G1 of H. neolaevis figured by Deb (1999: Fig. 4 ) is inaccurate, being much shorter and stouter in her illustration.The actual G1 closely resembles that of A. quadridentatus , except that the tip is more rounded and less produced ( Fig. 10G, H ), but this can easily be explained by variation. In addition, the male sternite 8 of the types of H. neolaevis are exposed when the male pleon is closed ( Fig. 8D ; see also Ng and Clark, 2008; Hsueh et al., 2009).

Aniptumnus quadridentatus is a mangrove species, occurring in brackish waters. The type locality, Pontianak , is a port at the opening of the Kapuas River in Borneo and is surrounded by mangroves. In Malaysia and Singapore, the species is often found among fouling communities in mangrove and estuarine habitats. When present, it often occurs in large numbers.

Figures

Figure 4. Eurycarcinus integrifrons De Man, 1879, paratype ovigerous female of Eurycarcinus bengalensis Deb, 1999 (CW 21.3 mm; CL 15.3 mm) (ZSI-C3349/2), Chamta Block, India. A, habitus, dorsal view; B, frontal view; C, chelae, outer view; D, anterior thoracic sternum (sternites 1–4) and pleon.

Figure 7. Aniptumnusquadridentatus (De Man,1895), male (CW 13.9mm; CL9.6 mm)(ZSI-C1503/2) Matla River, India(lectotype of Heteropanope neolaevis Deb, 1995); A, habitus, dorsal view; B, chelae, outer view.

Figure 8.Aniptumnusquadridentatus (De Man, 1895), male (CW13.9 mm; CL 9.6mm) (ZSI-C1503/2) Matla River,India(lectotype of Heteropanope neolaevis Deb, 1995); A, fourth ambulatory leg merus and basis-ischium lateral view; B, pleon; C, frontal margin; D, posterior thoracic sternum and pleon.

Figure 10. A–C, Pilumnopeus convexus (Maccagno, 1936), male (CW 15.3 mm, CL 11.3 mm) (LFSc.ZRC-70), Kuda, India; D–F, Heteropanope glabraStimpson,1858, male (CW 14.4mm, CL10.1 mm) (LFSc.ZRC-66), Ghoghamangroves,India; G–I, Aniptumnus quadridentatus (De Man, 1895), male (CW 13.9 mm; CL 9.6 mm) (ZSI-C1503/2) Matla River, India (lectotype of Heteropanope neolaevis Deb, 1995). A, D, G, ventral view of left G1; B, E, H, ventral view of distal part of left G1; C, F, I, left G2.