Parahelice pilimana (A. Milne-Edwards, 1873 )

Shih, Hsi-Te, Hsu, Jhih-Wei, Li, Jheng-Jhang, Ng, Ngan Kee & Lee, Jung-Hsiang, 2020, The identities of three species of Parahelice Sakai, Türkay & Yang, 2006 (Crustacea: Brachyura: Varunidae) from the western Pacific, based on morphological and molecular evidence, Zootaxa 4728 (2), pp. 249-265 : 255-257

Parahelice pilimana (A. Milne-Edwards, 1873)

( Figs. 3 , 4 )

Helice pilimana A. Milne-Edwards, 1873: 313 (part), pl. 18(1a) [not pl. 18(1, 1b) = Pse. subquadrata ] (type locality: New Caledonia); Serène 1968: 109 (list).

Pseudohelice (Parahelice) pilimana— Sakai et al. 2006: 50, figs. 65, 71, 73, 82, 83 (part?) ( New Caledonia; Indonesia: Lombok; Maluku; Flores).

Parahelice pilimana — Ng et al. 2008: 227 (list); Nishigaki et al. 2011: 88, figs. 2, 3 (part) [not fig. 2F = Par. daviei ] (Ishigaki, Japan).

Material examined. Taiwan: 1 ♂ (8.6 mm) ( NMMBCD 4055 ), Baoli R. estuary, Pingtung, coll. J.-J. Li, 28 Mar. 2014 ; 1 ♂ (10.4 mm) (NCHUZOOL 15666), Baoli R. estuary, Pingtung, coll. J.-J. Li, 23 June 2016 ; 2 ♂♂ (7.9–8.0 mm) (NCHUZOOL 15667), 1 ♀ (10.7 mm) (NCHUZOOL 15668), 1 ovig. ♀ (10.7 mm) (NCHUZOOL 15669), Baoli R. estuary, Pingtung, coll. P.-Y. Hsu & J.-W. Hsu, 3 Sep. 2017 ; 1 ♂ (11.6 mm) (NCHUZOOL 15678), 1 ♀ (7.4 mm) (NCHUZOOL 15681), Baoli R. estuary, Pingtung, coll. P.-Y. Hsu, 18 Mar. 2018 .

Diagnosis. Carapace quadrate, slightly broader than long, 1.21 times as broad as long (n = 8); surface convex, weakly punctate, granulate, with distinct groove between epigastric regions. Frontal margin slightly concave. Anterolateral margin with 3 teeth. Infraorbital ridge in male heteromorphic, proximal part with 6–8 rounded tubercles, followed by elongate, laterally, particularly vertically inflated crest, distal part with 2 rounded tubercles; female with 18–22 concentrated isomorphically interspaced, rounded tubercles. Chelipedal palm stout, surface conspicuously finely punctate; usually unequal in male, distinct patch of setae at base of fingers, mostly expanding onto fixed finger; chelipeds in females usually equal, distinct patch of setae at base of fingers but less than in males. Ambulatory legs broad, anterior margins of merus, carpus, and propodus covered with short setae. Male G1 slender, tapering, slightly curved towards distal end; female vulvae sunken in lateral part, with elongate semicircular operculum.

Ecological notes. The habitat is muddy substrate, with or without vegetation in southern Taiwan, at a distance of 600–800 m from a river mouth ( Fig. 7A, B ). This species is sympatric with Par. daviei , Par. pilosa , and Pse. subquadrata in southern Taiwan, with burrow depths of ca. 50 cm or less.

Distribution. From Japan (southern Ryukyus), Taiwan (Pingtung) (new record), Indonesia (Lombok; Maluku; Flores), to New Caledonia.

Remarks. Although we did not examine specimens of Parahelice pilimana from its type locality ( New Caledonia) or the adjacent area, the Taiwanese specimens agree well with the descriptions in A. Milne-Edwards (1873) and Sakai et al. (2006), including carapace ( Fig. 4A ; Sakai et al. 2006: figs. 82, 83), male chelae ( Fig. 4B; A . Milne- Edwards 1873: pl. 18(1a); Sakai et al. 2006: fig. 82), male infraorbital ridges ( Fig. 4C ; Sakai et al. 2006: fig. 65), and G1s ( Fig. 4 E–H; Sakai et al. 2006: fig. 71).

Morphological differences of males and females among Par. daviei , Par. pilimana , and Par. pilosa are shown in Table 2 (also see Remarks under Par. daviei ).

Of the type series of Par. pilimana , examined by A. Milne-Edwards (1873: 313, pl. 18(1, 1b)) only the male holotype can be considered as that species, and the rest of the specimens (MNHN-B 10996S) were later shown to be Pse. subquadrata instead by Sakai et al. (2006: 51), and so the morphology of the female is unknown. Sakai et al. (2006: 50) reported female specimens of Par. pilimana from Flores, Indonesia. While the female vulva was described ( Sakai et al. 2006: fig. 73), only a short description of the important character of the infraorbital ridge (“16 small mesial ones, followed by 2 larger, and 4 even larger lateral ones”; but not figured as in other species), and the condition of the patch of setae at base of fingers is not known. The female vulva structure, and the number of infraorbital tubercles of Par. pilimana and Par. daviei are similar ( Figs. 2D, I , 4D, I ; Table 2 ), and as such further examination of the morphologies of the infraorbital tubercles and chelae is necessary to confirm the species in Sakai et al. (2006). Judging from the figure of a female Par. pilimana provided in Nishigaki et al. (2011: fig. 2F), their specimens should be Par. daviei instead, because of the setal patch of the finger and the morphology of infraorbital ridge (cf. Figs. 1 , 2 ).

In Taiwan, this species is rare compared to other species of Parahelice (see Material examined), and only eight specimens were collected from southern Taiwan.

Figures

FIGURE 1. Parahelice daviei Sakai, Türkay & Yang, 2006. A, B, dorsal view of male; C, ventral view of male; D, chela of male; E, F, chela of female; G, H, color in life of male (Gangkou R. estuary, Pingtung, Taiwan; specimen not collected).A, C, D, ♂ (CW 12.1 mm; NCHUZOOL 15716; Baoli R. estuary, Pingtung, Taiwan); B, ♂ (CW 12.0 mm; NCHUZOOL 15670; Gangkou R. estuary, Pingtung, Taiwan); E, ♀ (CW 9.7 mm; NCHUZOOL 15692; Gangkou R. estuary, Pingtung, Taiwan); F, ♀ (CW 13.2 mm; NMMBCD 4049; Baoli R. estuary, Pingtung, Taiwan). Scale bars: 2.0 mm.

FIGURE 2. Parahelice daviei Sakai, Türkay & Yang, 2006. A–C, E–H, ♂ (12.0 × 9.7 mm, NCHUZOOL 15670); D, I, ♀ (13.2 × 10.6 mm, NMMBCD 4049). A, carapace; B, outer view of male right cheliped; C, left male infraorbital ridge; D, left female infraorbital ridge; E, F, dorsal view of right G1; G, H, ventral view of right G1; I, right vulva. Scale bars: A–D, 1.0 mm; E–I, 0.5 mm.

FIGURE 3. Parahelice pilimana (A. Milne-Edwards, 1873). A, dorsal view of male; B, ventral view of male; C, chela of male; D, chela of female. A–C, ♂ (CW 10.4 mm), D, ♀ (CW 10.7 mm) (NCHUZOOL 15666; Baoli R. estuary, Pingtung, Taiwan). Scale bars: 2.0 mm.

FIGURE 4. Parahelice pilimana (A. Milne-Edwards, 1873).A–C, E–H, ♂ (10.4 × 8.6 mm, NCHUZOOL 15666); D, I, ♀ (10.7 × 8.9 mm, NCHUZOOL 15668). A, carapace; B, outer view of male left cheliped; C, male left infraorbital ridge; D, female left infraorbital ridge; E, F, dorsal view of right G1; G, H, ventral view of right G1; I, right vulva. Scale bars: A–D, 1.0 mm; E–I, 0.5 mm.

FIGURE 7 Habitats and burrows (arrow) of Parahelice daviei, Par. pilimana, Par. pilosa and Pseudohelice subquadrata. A, B, habitat at Baoli R. estuary, Pingtung, Taiwan, about 600–800 m from a river mouth, where the four species are sympatric. C, habitat of Gangkou R. estuary, Pingtung, Taiwan, about 600–800 m from a river mouth, where Par. daviei and Pse. subquadrata are sympatric. D, habitat of Gadon Beach, Tabanan, Bali, Indonesia, about 50 m from a river mouth, where Par. pilosa and Pse. subquadrata are sympatric.