Parahelice daviei ( Sakai, Türkay & Yang, 2006 )

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 : 252-254

Parahelice daviei ( Sakai, Türkay & Yang, 2006)

( Figs. 1 , 2 )

Pseudohelice (Parahelice) daviei Sakai, Türkay & Yang, 2006: 48 , figs. 66, 68, 77, 78 (type locality: Irian Jaja, Papua, Indonesia).

Parahelice daviei — Ng et al. 2008: 227 (list); Nishigaki et al. 2011: 86, figs. 1A–D, 2F (part?) (Ishigaki, Japan).

Parahelice pilimana — Nishigaki et al. 2011: 88 (part), fig. 2F (Ishigaki, Japan). Not Par. pilimana (A. Milne-Edwards, 1873) .

Pseudohelice subquadrata — Li & Chiu 2013 : upper right image on p. 61. Not Pse. subquadrata (Dana, 1851) .

Material examined. Taiwan: 1 ♂ (8.1 mm) (NCHUZOOL 15715), Lanyang R. estuary, Yilan, coll. P.-Y. Hsu, 15 Apr. 2018 ; 1 ♀ (13.2 mm) ( NMMBCD 4049 ), Baoli R. estuary, Pingtung, coll. J.-J. Li, 25 Mar 2014 ; 1 ♂ (9.9 mm), 1 ♀ (12.4 mm) ( NMMBCD 4046 ), Baoli R. estuary, Pingtung, coll. J.-J. Li, 28 Mar. 2014 ; 2 ♂♂ (9.7–10.9 mm) (NCHUZOOL 15682), Baoli R. estuary, Pingtung, coll. J.-J. Li, 23 June 2016 ; 2 ♂♂ (9.3–10.6 mm) ( NCHU- ZOOL 15673 ), Baoli R. estuary, coll. P.-Y. Hsu and J.-W. Hsu, 11 July 2017 ; 1 ♂ (12.1 mm) (NCHUZOOL 15716), Baoli R. estuary, Pingtung, coll. P.-Y. Hsu et al., 18 Mar. 2018 ; 1 ♂ (7.2 mm), 1 ♀ (9.3 mm), 1 ovig. ♀ (12.0 mm) (NCHUZOOL 15679), Baoli R. estuary, Pingtung, coll. J.-J. Li, 18 July 2018 ; 3 ♀♀ (10.2–14.6 mm) (NCHUZOOL 15674), 1 ♀ (14.2 mm) (NCHUZOOL 15677), 1 ♀ (15.0 mm) (NCHUZOOL 15680), Baoli R. estuary, Pingtung, coll. P.-Y. Hsu et al., 6 Nov. 2018 ; 1 ♂ (12.0 mm) (NCHUZOOL 15720), Gangkou R. estuary, Pingtung, coll. J.-H. Lee, 21 June 2009 ; 1 ♀ (17.8 mm) (NCHUZOOL 15730), Gangkou R. estuary, Pingtung, coll. J.-H. Lee, 21 Nov. 2009 ; 1 ♂ (12.0 mm) (NCHUZOOL 15670), 2 ♂♂ (9.6–9.7 mm) (NCHUZOOL 15684), 4 ♀♀ (13.1–17.2 mm), 3 ovig. ♀♀ (12.0– 13.9 mm) (NCHUZOOL 15701), Gangkou R. estuary, Pingtung, coll. J.-H. Lee and W.-C. Wang, 30 Mar. 2010 ; 1 ♀ (10.9 mm) ( NMMBCD 4042 ), Gangkou R. estuary, Pingtung, coll. J.-J. Li, 30 July 2013 ; 1 ♂ (12.4 mm), 1 ♀ (15.7 mm) (NCHUZOOL 15686), Gangkou R. estuary, Pingtung, coll. J.-J. Li, 5 June 2015 ; 1 ♀ (13.1 mm) (NCHUZOOL 15683), 2 ♀♀ (10.6–14.0 mm) (NCHUZOOL 15685), Gangkou R. estuary, Pingtung, coll. J.-J. Li, 24 May 2016 ; 2 ♂♂ (13.2–13.4 mm) (NCHUZOOL 15687), Gangkou R. estuary, Pingtung, coll. J.-J. Li, 5 July 2016 ; 1 ♂ (11.7 mm) (NCHUZOOL 15676), Gangkou R. estuary, Pingtung, coll. P.-Y. Hsu & C.-Y. Chi, 4 Dec. 2016 ; 2 ♂♂ (12.8–13.9 mm) (NCHUZOOL 15690), 1 ♀ (9.7 mm) (NCHUZOOL 15692), Gangkou R. estuary, Pingtung, 11 July 2017 ; 3 ♂♂ (9.0– 11.7 mm), 1 ovig. ♀ (13.0 mm) (NCHUZOOL 15672), 2 ♀♀ (14.4–16.8 mm) (NCHUZOOL 15717), Gangkou R. estuary, Pingtung, 19 Mar. 2018 ; 4 ♂♂ (8.5–10.8 mm), 5 ♀♀ (12.1–15.6 mm) (NCHUZOOL 15695), 4 ♂♂ (10.1–14.3 mm) (NCHUZOOL 15671), 10 ♀♀ (9.8–16.0 mm) (NCHUZOOL 15675), Gangkou R. estuary, Pingtung, coll. P.-Y. Hsu & J.-W. Hsu, 7 Nov. 2018 .

Diagnosis. Carapace quadrate, slightly broader than long, 1.23 times as broad as long (n = 64); surface convex, weakly punctate, granulate, with distinct groove between epigastric regions. Frontal margin slightly concave. Anterolateral margin with 3 teeth including orbital tooth; last tooth weak, indistinct. Infraorbital ridge in male heteromorphic, proximal part with 4–8 rounded tubercles, followed by elongated, laterally Y-shaped crest, distal part with rounded tubercle; female with 14–21 sparse isomorphically interspaced, rounded tubercles. Cheliped palm stout, surface finely punctate; usually unequal in male, distinct patch of setae at base of fingers, mostly expanding onto fixed finger; chelipeds in female usually equal, inconspicuous patch of setae at base of fingers or glabrous. Ambulatory legs broad, anterior margins of merus, carpus, propodus covered with short setae. G1 slender, tapering, slightly curved towards distal end; vulvae sunken in lateral part, with elongated 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. 7 A–C). This species is sympatric with Par. pilimana , Par. pilosa and Pse. subquadrata in southern Taiwan, with burrow depths of ca. 50 cm or less.

Distribution. From Japan (southern Ryukyus), Taiwan (Yilan and Pingtung) (new record), to Indonesia (Papua).

Remarks. Although we did not examine specimens of Par. daviei from its type locality (Irian Jaya, Papua, Indonesia) or the adjacent area, the Taiwanese specimens agree well with the original description ( Sakai et al. 2006), including carapace ( Fig. 2A ; Sakai et al. 2006: figs. 77, 78), male chelae ( Fig. 2B ; Sakai et al. 2006: fig. 77), male infraorbital ridges ( Fig. 2C ; Sakai et al. 2006: fig. 66), and G1 ( Fig. 2 E–H; Sakai et al. 2006: fig. 68).

While males of Par. daviei , Par. pilimana and Par. pilosa can be separated by the distinct characters of infraorbital ridges and chelae, the morphologies of females are similar and can only be distinguished by minor differences ( Table 2 ).

Morphologically, the shapes of the chelipeds and vulvae of females of Par. daviei and Par. pilimana are very similar, but they can be distinguished by the infraorbital ridge and the setae on the outer surface of the palms. Based on the female specimens examined, the rounded tubercles of the infraorbital ridge are sparser in female Par. daviei ( Fig. 2D ) (vs. more concentrated in female Par. pilimana , Fig. 4D ), and the outer surface of the palm in female Par. daviei is relatively less setose ( Fig. 1E ) and sometimes glabrous ( Fig. 1F ; probably due to abrasion) (vs. with a distinct patch of setae in female Par. pilimana , Fig. 3D ).

In life, Par. daviei has distinct orange chelipeds and a brown carapace in both adult sexes ( Fig. 1A, D, G, H ). According to this feature, one of the figures of “ Pse. subquadrata ” in Li & Chiu (2013: upper right image on p. 61) should be Par. daviei instead (the chelipeds of Pse. subquadrata are gray).

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.