Pseudolitochira maenosonoi, Ng & Clark, 2022

Ng, Peter K. L. & Clark, Paul F., 2022, Descriptions of three new Pseudolitochira Ward, 1942 species (Crustacea: Brachyura: Pilumnidae) from the West Pacific, Journal of Natural History 56 (5 - 8), pp. 349-364 : 351-359

Pseudolitochira maenosonoi sp. nov.

( Figures 1 ; 3 ; 4 ; 7a, d–h )

Litocheira integra – Sakai 1955: 108, text-fig. 3 (not Carcinoplax integra Miers, 1884 ).

Heteropilumnus integra – Sakai 1976: 493, text-fig. 264a; Nagai and Nomura 1988: 112; Motoh 2003: 20.

Heteropilumnus integer — Miyake 1983: 233; Ito 1992: 46; Nomura et al. 1996: 17; Jeng 1997: 16, 22.

Pseudolitochira integra — Takeda and Miyake 1976: 110; Ng et al. 2001: 31; Marumura and Kosaka 2003: 61; Naruse 2010: 32 (part); Komatsu 2011: 274; Ng et al. 2017: 63; Maenosono 2019: 33, figs 8C, 11, 13C, 14M, N.

Material examined

Holotype. Male , 4.5 × 2.8 mm, RUMF-ZC-5196, Sakimotobu , Motobu , Okinawa Island, Japan, coll. T. Maenosono, 4 December 2017.

Paratypes. 1 female, 5.5 × 3.3 mm, RUMF-ZC-7649, same data as holotype; 1 female, 5.6 × 3.4 mm, RUMF-ZC-5190, Yona , Kunigami, Okinawa Island, Japan, coll . T. Maenosono, 21 May 2008; 1 female, 5.0 × 3.1 mm, RUMF-ZC-5191, Yona , Kunigami, Okinawa Island, Japan, coll . T. Maenosono, 14 May 2016; 1 female, 5.5 × 3.4 mm, RUMF-ZC-5192, Inanse , Urasoe, Okinawa Island, Japan, coll . T. Maenosono, 12 June 2010; 1 male, 4.7 × 3.0 mm, ZRC 2021.828 , ex RUMF-ZC -5193, Hanashiro , Yaese, Okinawa Island, Japan, coll . T. Maenosono, 20 July 2013; 1 male, 4.4 × 2.9 mm, RUMF-ZC-5194, Bise , Motobu, Okinawa Island, Japan, coll . T. Maenosono, 17 May 2010; 1 female, 5.3 × 3.3 mm, RUMF-ZC-5195, Bise , Motobu, Okinawa Island, Japan, coll . T. Maenosono, 2 January 2018; 1 female, 6.8 × 3.9 mm, ZRC 2021.829 , ex RUMF-ZC-5197, Bise , Motobu, Okinawa Island, Japan, coll . T. Maenosono, 23 December 2014; 1 female, 5.6 × 3.5 mm, RUMF-ZC -5198), Odo Coast , Itoman, Okinawa Island, Japan, coll . T. Maenosono, 26 May 2009 .

Diagnosis

Carapace transversely subrectangular, width 1.52–1.74 times length ( Figures 1a, b , and 3a, b ); surface covered with short, relatively dense pubescence which obscures surface and margins, with long simple setae along margins which do not obscure margin ( Figures 1a, b , and 3a, b ); anterolateral margin with last tooth small but distinct, first tooth similar in size to last tooth or present as low lobe ( Figure 3a, b ); posterior margin of epistome with median lobe raised, lateral margin gently concave ( Figure 3c, d ); third maxilliped with short, subquadrate ischium, merus quadrate, subdistal margin with very small granules ( Figures 3e , and 7a ); major chela with fingers subequal to or almost as long as length of palm ( Figure 4a, b ); ambulatory legs with merus and propodus relatively short, stout ( Figure 4e, f ); vulvae large, ovate, positioned close to median part of sternite 6, opening obliquely ( Figure 4d ).

Etymology

This species is dedicated to Tadafumi Maenosono, whose intrepid explorations have over the years uncovered many rare Japanese species.

Remarks

Old Japanese records of ‘ P. integra ’ fit what is here described as P. maenosonoi sp. nov. Sakai (1955, p. 108, text-fig. 3) first recorded the species as Litocheira integra from the Bonin Islands (= Ogasawara Islands) in Japan. Sakai (1976, p. 493, text-fig. 264a) subsequently transferred it to Heteropilumnus , but noted that ‘According to the original description, this species has the anterolateral borders entire. In the present specimen, however, the left anterolateral border marked with 2 rudimentary indentations, the right side almost entire’. His figure and comments agree well with what is here described as P. maenosonoi sp. nov.

Maenosono (2019, fig. 11A, B, C) described and figured material from Okinawa at length and discussed the Japanese records at length. He showed that the material of Naruse (2010) from Okinawa also contained Pilumnus turgidulus Rathbun, 1911 , while the record of Machida (2017) was Zehntneriana amakusae (Takeda and Miyake, 1969) . The records of this species by Sakai (1955, 1976) and Nagai and Nomura (1988) agree with the material of Maenosono (2019). Ng et al. (2021) noted that P. integra specimens of Maenosono (2019) differed from the type female in carapace proportions, degree of protrusion of the frontal margin and armature of the anterolateral margin and may be a different species. The material of Maenosono (2019) was examined, and it is here referred to Pseudolitochira maenosonoi sp. nov. Records of this species from Japan and Taiwan ( Takeda and Miyake 1976; Miyake 1983; Ito 1992; Nomura et al. 1996; Jeng 1997; Ng et al. 2001; Marumura and Kosaka 2003; Motoh 2003; Komatsu 2011, 2017) should be re-examined, but they are also probably P. maenosonoi sp. nov.

The carapace proportions of P. maenosonoi sp. nov. vary, with larger specimens being relatively wider. The smallest ratio belongs to the smallest male (male, 4.4 × 2.9 mm, RUMF-ZC-5194); the largest ratio (of 1.74) is that of the largest female (6.8 × 3.9 mm, ZRC 2021.829). The carapace proportions of this species, however, even for the smallest specimen, are still wider than any of the other known species of Pseudolitochira .

For comparisons with congeners, see Discussion.

Figures

Figure 1. Overall dorsal views, Pseudolitochira maenosonoi sp. nov. (a) holotype male, 4.5 × 2.8 mm, RUMF-ZC-5196, Okinawa; (b) paratype female, 5.5 × 3.3 mm, RUMF-ZC-7649, Okinawa.

Figure 3. Pseudolitochira maenosonoi sp. nov. (a, c–f) holotype male, 4.5 × 2.8 mm, RUMF-ZC-5196, Okinawa; (b) paratype female, 5.5 × 3.3 mm, RUMF-ZC-7649, Okinawa. (a, b) dorsal view of carapace; (c, d) frontal view of cephalothorax; (e) left third maxilliped; (f) male anterior thoracic sternum and pleon.

Figure 4. Pseudolitochira maenosonoi sp. nov. (a, e) holotype male, 4.5 × 2.8 mm, RUMF-ZC-5196, Okinawa; (b–d, f) paratype female, 5.5 × 3.3 mm, RUMF-ZC-7649, Okinawa. (a) chelae; (b) right chela; (c) right chela; (d) thoracic sternum and vulvae; (e, f) right fourth ambulatory leg.

Figure 7. (a, d–h) Pseudolitochira maenosonoi sp. nov. (a) holotype male, 4.5 × 2.8 mm, RUMF-ZC -5196, Okinawa. (b) P. pacifica sp. nov., female, 5.2 × 3.5 mm, ZRC 2017.190, Vanuatu; (c) P. crinita sp. nov., female, 10.0 × 6.8 mm, ZRC 2021.298, Papua New Guinea. (a–c) third maxilliped; (d) pleon and telson; (e) whole G1; (f–g) distal tip of G1; H, G2; (a–d) denuded. Scale bars: a–d = 0.5 mm; e, h = 0.2 mm; f, g = 0.1 mm.