Austruca Bott, 1973

Shih, Hsi-Te & Poupin, Joseph, 2020, Fig. 2. Gonadal development during Yntema stages 15, 17, 19 in Bruggmanniella sanlianensis Lin, Yang & Tokuda, 2020, sp. nov., Zoological Studies 59 (26), pp. 1-28 : 7-21

Genus Austruca Bott, 1973

Austruca perplexa (H. Milne Edwards, 1852) ( Figs. 2A, C, D , 3 , 5A, C , 6E–I , 7A–C, F, G , 8A–D ,

9A–C , 10 )

Gelasimus perplexus H. Milne Edwards, 1852: 150, pl. 4(18) [type locality: Java]; A. Milne-Edwards 1873: 274 [ New Caledonia]; Hilgendorf 1879: 806.

Gelasimus annulipes – Kingsley 1880: 148 [part; Australia]. (not Gelasimus annulipes H. Milne Edwards, 1837).

Uca annulipes var. orientalis Nobili, 1901: 13 , fig. A [type locality: Buntal, Kuching, Sarawak, Malaysia]; Nobili 1903: 21 [ Indonesia: Samarinda, Kalimanda Timur]; Maccagno 1928: 36, fig. 21 [ Malaysia: Buntal, Kuching, Sarawak]; Nobili 1906b: 151 [Malay Archipelago]; Oliveira 1939: 131 [list; Borneo].

Uca perplexa – Rathbun 1910: 306, pl. 1(1–2) [ Indonesia: Maluku; Sulawesi]; Rathbun 1924: 10; Barnwell 1980: 957 [central Philippines; Indonesia: Jakarta]; Davie 1982: 205 [ Australia]; George and Jones 1982: 83, figs. 6, 7b, 54a–f, 58e [ Australia]; Takeda 1982: 209 [ Japan: Ryukyus]; Ho et al. 1993: 20 [ Taiwan: Taitung]; Yamaguchi and Baba 1993: 506 [ Japan: Okinawa]; Jones and Morgan 1994: 199, 1 unnumbered fig. [eastern Australia]; Okutani 1994: 214, fig. 1 [ Japan: Ryukyus]; Tan and Ng 1994: 83 [ Singapore; Malay Peninsula]; Yamaguchi 1994: 165 [Malaya; Indonesia; Thailand]; Wang and Liu 1996: 61, 2 unnumbered figs. [ Taiwan]; Hung 2000: 140-1, figs. 438–439 [Penghu, Taiwan]; Lee 2001: 103, 3 unnumbered figs. [ Taiwan]; Ng et al. 2001: 37 [list; Taiwan]; Rosenberg 2001: 860 [ Philippines: Batangas Bay, Luzon]; Yoshigou 2001: 4, fig. 2, pl. 1N [ Japan: Ryukyus]; Wang and Liu 2003: 82, figs. 84–86 [ Taiwan]; Shen and Jeng 2005: 166, 1 unnumbered fig. [ Taiwan: Penghu]; Takeda and Ueshima 2006: 103 [ Taiwan: Penghu; Japan: Okinawa; Palau]; Katsu 2007: 92, 5 unnumbered figs. [ Japan: Amami, Ryukyus]; Naiyanetr 2007: 132 [ Thailand]; Ng and Richer de Forges 2007: 326 [ New Caledonia; list]; Juncker and Poupin 2009: 14, 75, pl. 5 (3 unnumbered figs.) [ New Caledonia]; Shih et al. 2009: 376 [ Taiwan]; Barnes 2010: 250, fig. 1 [ Indonesia: Ambeuan, Sulawesi]; Liu and Wang 2010: 41, 3 unnumbered figs. [ Taiwan]; Poupin 2010: 75 [part; New Caledonia]; Shih 2012: 66, figs. 94–96 [ Taiwan: Dongsha]; Shih et al. 2013: 643 [ Taiwan]; Fujita and Uyeno 2015: 95, fig. 2A, B [ Japan: Ryukyus]; Kumaralingam et al. 2017: 121, 1 unnumbered fig. [ India: Great Nicobar].

Uca annulipes subsp. orientalis – Tesch 1918: 37 [list].

Uca lactea – Boone 1934: 199, pl. 103 [ New Caledonia]; Miyake 1936: 511 [ Japan: Yaeyama, Ryukyus]; Sakai 1936: 171 [ Palau]; Miyake 1938: 109 [ Palau]; Miyake 1939: 222 [ Palau]. (not Ocypode (Gelasimus) lactea De Haan, 1835 ).

Austruca orientalis – Bott 1973: 322 [list].

Uca (Minuca) lactea – Serène 1973a: 132, figs. 5–7, 23–29, pls. 5, 7A, C, D [ New Caledonia]. (not Ocypode (Gelasimus) lactea De Haan, 1835 ).

Uca (Minuca) annulipes form intermedia – Serène 1973a: 138, figs. 19 (?), 20–22 [ Thailand: Phuket; Singapore; Indonesia: Sulawesi]; Serène 1973b: 359 [key]. (not Gelasimus annulipes H. Milne Edwards, 1837).

Uca (Celuca) lactea perplexa – Crane 1975: 300, figs. 18D–F, 19C–H, 26D, 31E, 54K, KK, 69C [part; west of Samoa and Fiji]; Miyake 1983: 163, pl. 55(1) [ Japan: Ryukyus]; Nagai and Nomura 1988: 55, 1 unnumbered fig. [ Japan: Ryukyus]; Shih 1994: 103, fig. 69 [ Taiwan].

Uca (Celuca) lactea lactea – Sakai 1976: 608 [part; Japan: Yaeyama, Ryukyus]; Wang 1984: 42 [ Taiwan: Pingtung]. (not Ocypode (Gelasimus) lactea De Haan, 1835 ).

Uca lactea perplexa – Fukui et al. 1989: 227 [ Taiwan: Pingtung]; Chen 2001: 208, 1 unnumbered fig. [ Taiwan]; Jaroensutasinee et al. 2003: 1–2 [ Thailand]; Nakasone and Irei 2003: 269, fig. 31F [ Japan: Ryukyus]; Jaroensutasinee and Jaroensutasinee 2004: 536 [ Thailand].

Uca annulipes – Ng and Sivasothi 1999: lower image on p. 76 [ Singapore]; Ng et al. 2007: upper image on p. 75, lower image on p. 76 [ Singapore]; Ng et al. 2008b: upper right image on p. 102) ( Singapore). (not Gelasimus annulipes H. Milne Edwards, 1837).

Uca perplesca [sic] – Nhuong 2003: 8 [southern Vietnam].

Uca (Paraleptuca) perplexa – Beinlich and von Hagen 2006: 26 [list; part]; Ng et al. 2008a: 241 [list; part]; Rahayu and Setyadi 2009: 106, 1 unnumbered fig., 1 fig. on p. 104 [ Indonesia: Papua]; Murniati and Pratiwi 2015: 71, 2 unnumbered figs., figs. 6.1, 8.12A, 8.13A [ Indonesia].

Uca (Austruca) perplexa – Naderloo et al. 2010: 24 , figs. 16a–g, 17a, b, 18c–f [part; west of Fiji]; Toyota and Seki 2014: 226, 4 unnumbered figs. [ Japan: Ryukyus]; Shih et al. 2016a: 62, fig. 2C–E [ Taiwan; Japan: Ryukyus].

Austruca perplexa – Shih et al. 2015a: 189, figs. 152–156 [ Taiwan]; Shih et al. 2016b: 153, 168, fig. 8F [part; Taiwan; New Caledonia]; Ng et al. 2017: 123 [list; Taiwan]; Fujita 2018: 72, fig. 5H [ Japan: southern Ryukyus]; Trivedi et al. 2018: 54 [list; part; Andaman and Nicobar islands]; Sasaki 2019: 12436 [list; part]; Tanase and Wada 2019: 1 [ Japan: Wakayama]; Wada 2019a: e142 [southern Vietnam]; Wada 2019b: e146 [ Indonesia: Sumatra; Bali; Sulawesi; Halmahera; Ambon]; Shih 2020: 140, figs. 172–173 [ Taiwan: Dongsha].

? Uca perplexa – Apreshgi et al. 2016: 102, fig. 1a, b [southwest India]. (see DISCUSSION).

? Uca (Austruca) perplexa – Patra et al. 2017: 209 [ India: West Bengal]. (see DISCUSSION).

Austruca (Austruca) perplexa – Rosenberg 2019: 734 [list; part].

Not Gelasimus perplexus – Heller 1865: 38, pl. 5(4) [ India: Madras; Ceylon]; A. Milne-Edwards 1873: 274 [ India]. (= Gelasimus variegatus Heller, 1862 ; see Shih et al. 2019).

Not Gelasimus annulipes var. orientalis – Laurie 1906: 426, fig. 11 [ Sri Lanka]. (= Gelasimus annulipes H. Milne Edwards, 1837).

Not Uca annulipes var. orientalis – Stephensen 1946: 189 [Persian Gulf]. (= Uca annulipes iranica Pretzmann, 1971 )

Not Uca annulipes var. orientalis – Barnard 1950: 97 [ Mozambique and South Africa]. (= Uca occidentalis Naderloo, Schubart & Shih, 2016 ).

Material examined: lectotype, ò (dry, CW 13.8 mm, PL 25.7 mm) (MNHN-IU-2008-10646 = MNHN-B.12005), M. Besukiil, Java, Indonesia. Paralectotype, 1 ò (rehydrated, broken, CW ~ 15–16 mm, PL 28.2 mm), same data as lectotype.

Others: Ryukyus, Japan: 1 ò (15.8 mm) (NCHUZOOL 14652), Oura Bay, Okinawa, 13 Nov. 1975; 10 òò (11.6–14.7 mm) (NCHUZOOL 15038), Oura Bay, Okinawa, 6 May 2012; 3 òò (9.6–15.1 mm), 1 ñ (7.9 mm) (NCHUZOOL 14654), Yuhi River (= R.), Okinawa, 19 Mar. 1992; 16 òò (11.2–17.5 mm) (NCHUZOOL 14646), Manzamo, Okinawa, coll. P.-C. Tsai, 7 Jul. 2009; 4 òò (11.0– 14.2 mm) (NCHUZOOL 14642), Sashiki, Okinawa, 28 Dec. 2011; 1 ò (7.1 mm), 2 ññ (6.5–10.6 mm) (NCHUZOOL 14650), Okinawa, 9 Jul. 2009; 2 òò (13.4–16.2 mm) (NCHUZOOL 14752), Nagura, Ishigaki, coll. T. Naruse, 23 Jun. 2004; 5 òò (13.5– 15.6 mm), 2 ññ (12.8–15.3 mm) (NCHUZOOL 14648), Funaura Bay, Iriomote, coll. P.-C. Tsai, 8 Jul. 2011. Taiwan: 1 ò (13.5 mm) (NCHUZOOL 14647), 1 ñ (12.6 mm) (NCHUZOOL 14674), Lanyang R. estuary, Yilan, 25 Jul. 2004; 4 òò (16.6–17.6 mm) (NCHUZOOL 14677), 3 òò (12.2–13.0 mm), 2 ñ (13.7– 13.7 mm) (NCHUZOOL 14643), Yanshuei R. estuary, Tainan, coll. J.-H. Lee et al., 4 Aug. 2009; 2 òò (14.4, 15.6 mm), 1 ñ (14.5 mm) (NCHUZOOL 14637), Dingtouer Shoal, Cigu, Tainan, coll. J.-H. Lee, 14 Aug. 2009; 2 òò (14.3–17.2 mm), 1 ñ (15.7 mm) (NCHUZOOL 14645), Gaoping R. estuary, Kaohsiung, coll. H.- T. Shih, 29 Apr. 1998; 1 ò (14.5 mm), 1 ñ (12.0 mm) (NCHUZOOL 14640), Dapengwan, Pingtung, 20 Jul. 2007; 2 òò (9.3–11.8 mm), 1 ñ (12.9 mm) (NCHUZOOL 13252), 1 ò (10.6 mm) (NCHUZOOL 13253), Baoli R. estuary, Pingtung, coll. H.- T. Shih, 7 Jul. 2001; 1 ò (14.0 mm), 1 ñ (12.1 mm) (NCHUZOOL 14641), Fengcueisha, Kenting, Pingtung, 18 May 2001; 3 òò (14.2–17.2 mm) ( NTOU), Dulanwan, Taitung, coll. P.-H. Ho, 7 Apr. 2001; 1 ò (15.1 mm) (NCHUZOOL 14675), Shihcyuan, Penghu, 21 Jun. 2006; 2 òò (13.3–16.5 mm) (NCHUZOOL 14639), Chihsi, Siyu, Penghu, 18 May 2007; 3 òò (15.8–16.4 mm) (NCHUZOOL 14649), Chihsi, Siyu, Penghu, 19 May 2007; 3 òò (12.2–17.5 mm), 2 ññ (10.4–15.1 mm) (NCHUZOOL 14636), Dongsha Island, coll. C.-Y. Chung and Y.-H. Huang, 7 Jun. 2011; 1 ò (16.6 mm) (NCHUZOOL 14651), Dongsha Island, 19 Nov. 2011; 1 ñ (8.8 mm) (NCHUZOOL 15039), Dongsha Island, 20 Nov. 2011; 1 ò (11.8 mm) (NCHUZOOL 15066), Dongsha Island, 12 Feb. 2012; 1 ò (13.9 mm) (NCHUZOOL 15039), Dongsha Island, 23 Mar. 2012; 1 ò (17.6 mm) (NCHUZOOL 14644), 26 May 2012; 1 ò (11.0 mm) (NCHUZOOL 15067), Dongsha Island, 18 Nov. 2012. Philippines: 6 òò (10.0– 13.5 mm) ( ZRC 2020.0284), Municipality of Santa Ana, Cagayan, coll. T. Naruse and J. C. E. Mendoza, 23 Apr. 2007; 2 òò (10.5–12.3 mm), 1 ò (broken) (NCHUZOOL 15043), Puerto Galera, Mindoro, coll. K. Wong, 9 Jun. June 2009; 2 òò (12.7–15.2 mm) ( RMNH. CRUS.D.35194), Tablas Island, 14 Sep. 1981; 3 òò (10.1–12.6 mm) ( ZRC 2008.0721), Okoy R., Sibulan, Negros, coll. N. K. Ng et al., 5 Jul. 2002; 1 ò (13.1 mm) ( ASIZ 74979), Kawasan, Cebu, coll. H.-C. Liu, 25 Nov. 2001; 9 òò (8.7–12.8 mm), 4 ññ (9.1–11.7 mm) (NCHUZOOL 15063), 2 ññ (9.1–10.6 mm) (NCHUZOOL 15062), Matutinao R. Badian, Cebu, coll. H.- T. Shih et al., 6 Sep. 2003; 2 òò (9.9–12.9 mm), 2 ññ (11.1–12.3 mm) (NCHUZOOL 15041), Blue Water Club, Cebu, coll. J.- D. Lee, 20 Feb. 1998; 6 òò (10.9–12.9 mm) ( ASIZ 72886), Bohol, coll. H.-C. Liu, 20 Feb. 2003; 3 òò (12.0– 13.3 mm) (NCHUZOOL 15042), Bohol, coll. H.- T. Shih et al., 2 Sep. 2003; 1 ñ (8.3 mm) ( ASIZ CR 74975), Loboc R., Bohol, coll. H.-C. Liu, 21 Feb. 2003; 1 ñ (8.4 mm) ( ASIZCR), Loboc R., Bohol, coll. H.-C. Liu, 18 May 2004; 1 ò (14.8 mm) ( ZRC 2020.0285), Panglao, Bohol, 4 Jun. 2004; 2 òò (12.2–16.1 mm), 1 ò (broken) ( ZRC 2020.0286), Dumanhog, Siquijor, coll. N. K. Ng and J. L. Jozeph, 26 Jan. 2005; 1 ñ (10.8 mm) (NCHUZOOL 15044), Pago R., Mindanao, coll. H.-C. Liu, 13 Jul. 2007; 1 ò (11.5 mm), 1 ñ (9.1 mm) (NCHUZOOL 15045), Mindanao, coll. H.- C. Liu, 15 Jul. 2007; 4 òò (12.6–14.6 mm), 1 ò (broken) (NCHUZOOL 15064), 1 ò (9.7 mm), 7 ññ (8.4–11.8 mm) (NCHUZOOL 15065), Zamboanga, Mindanao, coll. C. K. R. Ong, 10 Jun. 2006. Palau: 1 ñ (10.9 mm) ( ZRC 2020.0287), coll. B. Y. Lee, 13 Jan. 2019. Malaysia: 1 ò (17.3 mm) (NCHUZOOL 15046), Buntal, Kuching, Sarawak, coll. H.- T. Shih et al., 28 Jul. 2010; 1 ò (15.9 mm) (NCHUZOOL 15047), 7 ññ (10.3–13.5 mm) (NCHUZOOL 15048), Petra Jaya, Kuching, Sarawak, coll. H.- T. Shih et al., 27 Jul. 2010; 1 ò (11.9 mm), 3 ññ (9.6–9.8 mm) (NCHUZOOL 15050), Santubong, Kuching, Sarawak, coll. H.- T. Shih et al., 26 Jul. 2010; 5 òò (13.2–15.4 mm), 1 ñ (11.3 mm) (NCHUZOOL 15052), Jeram, Selangor, coll. A. Sasekumar, 21 Mar. 2012; 11 òò (11.3–15.7 mm) (NCHUZOOL 15053), Port Dickson, Negeri Sembilan, coll. A. Sasekumar, 29 Feb. 2012; 1 ò (9.4 mm) ( NTOU), Parit Jawa Lant, Muar, Johor, coll. P.-H. Ho, 19 Jul. 2001; 8 òò (8.7–12.2 mm), 1 ñ (10.6 mm) (NCHUZOOL 15054), Tumpat, Kelantan, coll. A. Sasekumar, 28 Aug. 2013; 1 ò (11.6 mm) (NCHUZOOL 15055), Mersing, Johor, coll. H.- T. Shih et al., 19 Jul. 2010; 5 òò (7.9–14.4 mm) (NCHUZOOL 15056), Mersing, Johor, coll. H.- T. Shih et al., 20 Jul. 2010. Singapore: 2 òò (10.0– 12.2 mm) ( ZRC 1987.346-365), west coast, coll. S. Harminto, 18 Sep. 1986; 2 òò (12.0– 15.3 mm) ( ZRC 2006.0038), Pulau Hantu, Spore, coll. Z. Jaafar, 19 Apr. 2002; 1 ò (15.2 mm) ( ZRC 2020.0288), Sultan Shoal, coll. P. K. L. Ng, Dec. 2008; 1 ò (14.9 mm) (NCHUZOOL 15057), 3 òò (14.0– 14.1 mm) (NCHUZOOL 15058), Sarimbun, coll. H.- T. Shih, 4 Mar. 2012. Indonesia: 1 ò (13.1 mm) ( ZRC 2000.1742), between Mapane and Poso mangroves, Sulawesi, coll. C. D. Schubart, 20 Jan. 2000; 1 ò (10.4 mm) ( ZRC 2009.0928), Bunaken, Sulawesi, coll. N. K. Ng and C. Y. Lai, 18 Sep. 2003; 2 òò (11.2–12.7 mm) ( ZRC 2020.0289), Bunaken, Sulawesi, coll. N. K. Ng and C. Y. Lai, 23 Sep. 2003; 2 òò (14.3–14.5 mm) ( MZB Cru 3669), Belawan, Medan, Sumatra, coll. Arifin, 27 Dec. 2011; 1 ò (13.7 mm) ( MZUF 4294), Nusa Dua, Bali, coll. Feb. 1987; 11 òò (8.4–11.0 mm), 4 ññ (9.5–11.3 mm), 1 ovig. ñ (9.1 mm) (NCHUZOOL 15059), Nusa Dua, Bali, coll. H.- T. Shih, 16 Jul. 2014; 4 òò (10.9–14.2 mm), 4 ññ (8.7–11.9 mm) (NCHUZOOL 15060), Gerokgak, Bali, coll. H.- T. Shih, 18 Jul. 2014; 2 òò (13.3–13.4 mm) ( ZRC 2017.0916), Tanjong Ringgit Temiak, Lombok, 13 Feb. 2002; 4 òò (10.4–16.3 mm), 1 ò (broken) ( ZRC 2009.0933), Kuta, Lombok, coll. Z. Jaafar and A. Anker, 11 Feb. 2002; 5 òò (11.2–12.0 mm) ( SMF 24578), Ambon Bay, Ambon, Maluku, coll. A. Ratraubun, 12 Oct. 1998; 4 òò (11.5–14.4 mm) ( ZRC 2020.0290), Ambon, coll. H. H. Tan, 19 Aug. 2012; 2 òò (14.9–15.3 mm) ( MZB Cru 1685), Warsamdin beach, Waigeo Island, Papua Barat, West Papua, coll. C. M. Sidabalok, 4 Jun. 2007; 2 òò (12.7–15.6 mm) ( MZB Cru 3906), Kamora, Papua Barat, West Papua, coll. D. L. Rahayu, no date. Papua New Guinea: 1 ò (6.8 mm), 3 ññ (8.1–9.5 mm) ( UF 2333), Milne Bay, Louisiade Archipelago, coll. G. Paulay, 4 Jun. 1998. Australia: 3 òò (11.4–15.0 mm) ( SMF 17148), Tannum Sands 25 km from Gladstone, sand mangroves, coll. G. Hartmann and G. Hartmann- Schröder, 28 Jan. 1976; 2 òò (8.7–10.0 mm) ( QM W18212), Starcke River mouth, Queensland, coll. P. Davie, J. Short and A. Humpherys, 13 Nov. 1992; 1 ò (12.5 mm) ( QM W19270), Urangan boat harbor, Hervey Bay, Queensland, coll. P. Davie, J. Short and A. Humpherys, 25 Oct. 1993; 1 ò (12.0 mm) ( ZRC 1995.966), Thomatis Creek mouth (16.49.8S, 145.43.8E), coll. P. Davie, J. Short and A. Humpherys, 30 Oct. 1993. New Caledonia: 4 òò (6.7–13.5 mm), 3 ññ (7.1–9.5 mm) (MNHN-IU-2017-9118), CRISP 2009, st. 6, Koné Mangrove IFREMER, coll. J. Poupin and M. Juncker, 9 Mar. 2009; 1 ò (7.3 mm) (MNHN-IU-2017-9119), st. 8, Mangrove Oundjo Voh, coll. J. Poupin and M. Juncker, 11 Mar. 2009; 2 òò (8.9–10.2 mm), 2 ññ (7.9–12.6 mm) (MNHN- IU-2017-9120), st. 9, Presqu’île Pindaï, coll. J. Poupin and M. Juncker, 12 Mar. 2009; 1 ò (9.0 mm) (NCHUZOOL 13564), 2 òò (9.7–10.5 mm), 1 ò (broken) (NCHUZOOL 13573), Ouano Bay, coll. B. Richer de Forges, 30 Nov. 2008; 2 òò (11.0– 11.9 mm) (NCHUZOOL 15061), coll. B. Richer de Forges, no date. Solomon Islands: 9 òò (10.5–15.5 mm), 1 chela, 2 ññ (12.0– 14.9 mm) ( AM P98278), Guadalcanal, coll. R. T. Springthorpe, coll. McCoy Society, 7 Oct. 1991.

Diagnosis: Male. Carapace ( Figs. 3D , 5A , 7A– C ) subrectanglar, smooth; front broad; anterolateral angles (= external orbital angles) triangular, directed anterolaterally; anterolateral margins moderately convergent, short; dorsolateral margins clear, long. Major cheliped ( Figs. 2C, D , 3A, B, E , 5C , 8A– D ) without groove on outer fingers; pollex narrower than dactylus for entire length, with moderate to large predistal triangular tooth; dactylus wider at base, narrower toward distal part, then arched and tapering in position of adjacent predistal pollex tooth. G1 ( Fig. 6E– I ) with strong torsion; thumb moderately long, reaching flange base, distal parts of both flanges broad, posterior flange longer, broader than anterior. Urocardiac ossicles of gastric mill ( Fig. 9A–C ) moderately complex, with 3 or 4 pairs of transverse ridges of median tooth, separated by gaps reached deeply near central ridge, on posterior tooth plate; 2 pairs of cusps on stem region.

Female: Carapace ( Fig. 7F–G ) with anterolateral region swollen, anterolateral angle sharper triangular, directed anterolaterally.

Size: Largest male CW 37.5 mm, CL 19.5 mm, PL 11.5 mm (Ryukyus); largest female CW 16.0 mm, CL 10.0 mm ( Singapore) ( Crane 1975).

Color in life: Adults with carapace marbled transversely with brown (or dark brown) and white; entire major cheliped from pink, yellow to yellowish white, fingers white; walking legs marbled with brown and white; most females with carapace and legs with homogenous white or brownish yellow ( Fig. 10 ).

Distribution: Indo-West Pacific: Nicobar Islands, Indonesia, Malay Peninsula, Borneo, Thailand, Cambodia, Vietnam, Taiwan, Japan, Philippines, Palau, New Guinea, Australia, Solomon and New Caledonia ( Fig. 1 ).

Remarks: See Remarks under Austruca citrus for the differences between A. perplexa and the closely related A. citrus n. sp.

Austruca citrus n. sp. ( Figs. 4 , 5B, D, E , 6A–D, J , 7D–E, H , 8E–H , 9D , 11 , 12A, B ) urn:lsid:zoobank.org:act:55512189-203E-4987-8368-770DC6BD02C9

Gelasimus annulipes – Miers 1886: 244 [part; Fiji]; Ortmann 1894: 758 [ Samoa].

Uca lactaea [sic] – Pesta 1913: 57 [ Samoa].

Uca lactea – Balss 1938: 76 [ Fiji].

Uca (Celuca) lactea perplexa – Crane 1975: 292, figs. 18D–F, 19B, 20A–C, 26D, 31E, 54K, KK, 69C, pl. 39E–F [part; Samoa; Fiji].

Uca (Paraleptuca) perplexa – Beinlich and von Hagen 2006: 26 [list; part]; Ng et al. 2008a: 241 [list; part].

Uca perplexa – Poupin and Juncker 2008: 35, fig. 9C [ Wallis & Futuna]; Poupin 2010: 75 [part; Wallis & Futuna]; Weis and Weis 2013: fig. 1 [ Fiji].

Uca (Austruca) perplexa – Naderloo et al. 2010: 24 [part; Fiji; Tonga; Samoa].

Austruca perplexa – Shih et al. 2016b: 153, 168 [part; Wallis & Futuna]; Sasaki 2019: 12436 [list; part].

Austruca (Austruca) perplexa – Rosenberg 2019: 734 [list; part].

M a t e r i a l e x a m i n e d: Holotype: ò (10.9 × 6.7 mm, PL 17.6 mm) (MNHN-IU-2017-9121), Wallis & Futuna, CRISP 2007 , st. 24, coll. A. Malau, E. Liufau and C. Manry, Jan. 2010 . Paratypes: Wallis & Futuna: 1 ò (11.1 mm), 2 ññ (8.4–11.7 mm) (MNHN-IU-2017-9122), Halalo mangrove de Halalo, near gas terminal, coll. J. Poupin and M. Juncker, 23 Oct. 2007; 13 òò (8.5–12.7 mm), 1 ñ (10.4 mm) (MNHN-IU-2017-9123), same data as holotype; 1 ò (11.3 mm) (NCHUZOOL 14912), CRISP 2007, st. 29, coll. J. Poupin and M. Juncker, 25 Oct. 2007; 3 òò (8.3–10.1 mm) (NCHUZOOL 15035), 3 òò (11.3–11.90 mm) (NCHUZOOL 15036), same data as holotype.

Others: Fiji: 1 ò (12.9 mm) (UF 3843), Viti Levu Island (= I.), coll. L. Kirkendale and V. Bonito, 18 Sep. 1982; 4 òò (9.6–11.0 mm) (UF 1488), 1 ò (11.6 mm) (NCHUZOOL 15037), Viti Levu I., coll. G. Paulay, 19 Oct. 2001; 1 ò (8.7 mm) (ZRC 2019.1320), Suva point beach, Suva, coll. B. Y. Lee and B. Rashni, 22 Jul. 2019; 1 ò (13.6 mm) (ZRC 2019.1316), 3 òò (8.6–11.9 mm) (ZRC 2019.1319), Nasoso mangroves, Nadi, coll. B. Y. Lee and B. Rashni, 28 Jul. 2019; 1 ò (14.6 mm) (ZRC 2019.1317), 6 òò (8.3–14.6 mm) (ZRC 2019.1321), Denarau mangroves, Nadi, coll. B. Y. Lee and B. Rashni, 28 Jul. 2019. Samoa: 1 ò (11.5 mm) (SMF 17153), Upolu, Samoa, coll. Museum Godeffroy, no date; 4 òò (10.4–12.7 mm) (SMF 5675), Samoa, coll. Hauck, 1904.

Diagnosis: Male. Carapace ( Figs. 4A , 5B , 7D, E , 12A ) subrectanglar, smooth; front broad; anterolateral angles triangular, directed laterally; anterolateral margins moderately convergent, short; dorsolateral margins clear, long. Third maxillipeds ( Fig. 4D ) with merus about 1/3 length of ischium; longitudinal broad groove on outer surface of ischium and merus, close to inner margin. Male pleon ( Fig. 4C ) tapering from somites 2–5, somite 6 with lateral margin nearly straight. Major cheliped ( Figs. 4B , 5D, E , 8E–H , 12B ) without groove on outer fingers; pollex narrower than dactylus for entire length, with low, small to moderate predistal triangular tooth; dactylus with same width from base to position of adjacent predistal pollex tooth, then tapering and arched distally. Minor fingers without large tooth on occlusal margin, a large gap between fingers, about same width with adjacent fingers. G1 ( Fig. 6A–D, J ) with strong torsion; thumb moderately long, reaching flange base, distal parts of both flanges narrow, posterior flange longer, broader than anterior. Urocardiac ossicles of gastric mill ( Fig. 9D ) moderately complex, with 4 pairs of transverse ridges of median tooth, separated by gaps reached deeply near central ridge, on posterior tooth plate; 2 pairs of cusps on stem region.

Female: Carapace ( Fig. 7H ) with anterolateral angle more broadly triangular, directed laterally.

Size: Largest male CW 12.9 mm, CL 7.9 mm, PL 25.6 ( Fiji); largest female CW 11.7 mm, CL 7.4 mm ( Wallis & Futuna).

Color in life: Adults with carapace marbled with brown (or dark brown) and white; entire major cheliped chrome yellow, distal part of fingers white; walking legs, minor cheliped, third maxillipeds, orbital areas and pterygostomian regions always chrome yellow, sometimes deep pink; some females with carapace and legs with fine marbling of dark brown and gray ( Figs. 11A–G , 12A, B ).

Ecological and behavioral notes: High densities of individuals were found on middle and high intertidal zone of shelter shore, beside front mangroves with muddy sand substrate ( Figs. 11G, H , 12C ), as well as the interior flats along the tidal creek beside mangroves with about 1 km from the sea (B. Y. Lee, personal communication). The species has a unique aggressive behavior, a short, rapid and horizontal wave, toward the intruder which is different from the aggressive behavior with vertical wave of A. perplexa in Australia ( Crane 1975; How et al. 2007; Weis and Weis 2013).

Distribution: Fiji, Wallis & Futuna, Samoa and probably Tonga ( Fig. 1 ).

Etymology: The species name, Citrus , is from the Latin name for the lemon, alluding the lemon-colored major chela of the new species, which is very distinctive in the field. The name is used as a noun in apposition.

Remarks: Austruca citrus n. sp. is close to A. perplexa , but can be distinguished by the following characters, including the maximum adult size of males (CW 12.9 mm vs. CW 17.5 mm); the direction of the anterolateral angles of the male carapace (lateral vs. anterolateral) ( Figs. 4A , 5B , 7D, E vs. Figs. 3D , 5A , 7A–C , 12A ); the shape of anterolateral angles of the female carapace (relatively more broadly triangular vs. sharper triangular) ( Fig. 7H vs. Fig. 7F–G ); the ratios of major pollex length on carapace width (large vs. small; Fig. 13, see below); the major pollex (with a low, small to moderate predistal triangular tooth vs. with a moderate to large predistal triangular tooth) and the major dactylus (with the same width from the base to the position of the adjacent predistal pollex tooth vs. wider at the base and narrower toward the distal part) ( Figs. 4B , 5D, E , 8E–H , 12B vs. Figs. 2C, D , 3A, B, E , 5C , 8A–D ); the distal parts of both flanges of the G1 (narrow vs. broad) ( Fig. 6A–D, J ; Crane 1975: figs. 19B, 20A–C vs. Fig. 6E–I ; Crane 1975: fig. 19C–H); and the coloration of major cheliped (chrome yellow vs. pink, yellow or yellowish white) ( Figs. 11A–E, G , 12A, B vs. Fig. 10A–F ).

Crane (1975: figs. 19, 20A–C) illustrated the G1 variation of A. perplexa s. l. from different regions. There is a pattern that the distal parts of both flanges are broad in specimens from the Gulf of Siam, Singapore and the Philippines; and narrow in those from Fiji and Samoa, which agree with our observations ( Fig. 6 ). The distal part of the G1 from Australia in Crane (1975: fig. 19D) seems narrow, which might be caused by the specimens being small and/or figured from a different angle, because our specimens from Queensland (QM W19270) show this part as relatively broader ( Fig. 6I ). The distal parts of both flanges can be considered as a character to distinguish the two species, that is, it is broad for A. perplexa ( Fig. 6A–D, J ) and narrow for A. citrus ( Fig. 6E–I ).

The character of the urocardiac ossicles of the gastric mill is sometimes useful to separate species or genera of fiddler crabs ( Naderloo et al. 2010; Shih 2015; Shih et al. 2015b 2016b 2019), but the three or four pairs of transverse ridges of the median tooth in both A. perplexa and A. citrus ( Fig. 9 ) can only be considered as within the range of variation.

DNA analyses

A 567 bp segment (excluding the primer regions) of 16S rDNA from 70 specimens (excluding the outgroups) was amplified and aligned. Of these, 112 positions were variable and 85 parsimony informative, with 20 different haplotypes distinguished ( Table 1). The studied segment of the 16S rRNA sequences was AT rich (71.1%) (T, 36.3%; A, 34.8%; G, 18.2%; C, 10.7%). For the COI gene from 67 specimens (excluding the outgroups), a 658-bp segment was compared (except the haplotype “Ap-C2f” with 616 bp), resulting in 21 different haplotypes ( Table 1). The studied segment of the COI sequences was also AT rich (63.2%) (T, 35.1%; A, 28.0%; G, 17.5%; C, 19.3%). In this gene fragment, 174 positions were variable and 133 were parsimoniously informative.

The best model selected for the COI dataset is the HKY + G model (TRatio = 6.3137, gamma distribution shape parameter = 0.123). The phylogenetic tree of COI from the BI analysis, with the posterior probability and bootstrap values from the BI and MP analyses on the main nodes, is shown in figure 14. Based on the tree, Austruca perplexa s. l. is monophyletic with high branch support, and sister to A. lactea , with two clades corresponding to A. perplexa s. s. and A. citrus n. sp.

The pairwise nucleotide divergences for 16S rDNA and COI (in parentheses) with K2P distance and differences in the total bp numbers (gaps considered in 16S) are shown in tables 2 and 3, respectively. The interspecific K2P distances of 16S rDNA and COI of A. citrus n. sp. are 1.73% (1.29%–2.42%) and 4.59% (3.78%–5.28%) with the closest A. perplexa ; and the numbers of bp differences between the two species are 11.08 (8–16) and 28.85 (24–33), respectively ( Tables 2, 3).

Some specimens only have 16S rRNA sequences as the PCR of the COI failed. From the 16S sequences, specimens from the Samoa and Solomon Islands belong to the clades of A. citrus and A. perplexa , respectively ( Table 1).

Morphometric analysis

The PLs were plotted against the CWs for the males of three groups. The ANCOVA results show that the regression lines of A. citrus and A. perplexa , as well as the lines of A. citrus and A. perplexa with CW between 8.3–14.6 mm, differ significantly both in intercept (P -values = 0.016 and 0.03, respectively) and slope (P = 0.039 and P = 0.037, respectively). It is clear that, for a given CW of A. citrus (about 10–14.6 mm), the PL is longer than that of A. perplexa ( Fig. 13). The largest specimen of A. citrus ( Fiji, ZRC 2019.1317) is CW 14.6 mm, with PL 27.5 mm and the specimens with similar size (CW 14.4–14.7 mm) of A. perplexa have a PL of 20.8–26.9 mm (n = 7). The largest male of A. perplexa (CW 17.5 mm; Okinawa, Japan, NCHUZOOL 14646) has a PL of 34.6 mm.

Figures

Fig. 2. I llustrations of syntypes of Gelasimus perplexus, G. annulipes and Uca annulipes var. orientalis (A–C), and specimen of A. perplexa from Borneo (D). A, Gelasimus perplexus H. Milne Edwards, 1852 (after H. Milne Edwards 1852: pl. 4(18a)); B, Gelasimus annulipes H. Milne Edwards, 1837 (after H. Milne Edwards 1852: pl. 4(15b); C, Uca annulipes var. orientalis Nobili, 1901 (after Nobili 1901: fig. A); D, specimen from Buntal, Kuching, Sarawak, Malaysia (after Maccagno 1928: fig. 21).

Fig. 3. The syntypes of Gelasimus perplexus H. Milne Edwards, 1852 (MNHN-IU-2008-10646).A–C, male paralectotype, rehydrated specimen; D–E, male lectotype, dry specimen. A, B, outer and inner surfaces of major cheliped (PL 17 mm); C, broken carapace, CW ~15–16 mm; D, carapace, CW 13.8 mm; E, outer surface of major cheliped, PL 25.7 mm.

Fig. 5. Austruca perplexa (H. Milne Edwards, 1852) (A, C) and A. citrus n. sp. (B, D, E). A, B, carapace; C–E, major chela. A, C, male (NCHUZOOL 15053; CW 15.6 mm, PL 25.6 mm; Negeri Sembilan, Malaysia); B, D, holotype of A. citrus (MNHN-IU-2017-9121; CW 10.9 mm, CL 6.7 mm, PL 17.6 mm; Wallis & Futuna); E, male (UF 3843; CW 12.9 mm, PL 25.6 mm; Fiji).

Fig. 6. G1s of Austruca citrus n. sp. (A–D, J) and A. perplexa (H. Milne Edwards, 1852) (E–I). A–D, G–J, right G1; E–F, left G1. A, E, mesial view; B, G–J, mesial view of distal part; C, F, lateral view D, lateral view of distal part. A–D, holotype, CW 10.9 mm, MNHN-IU-2017-9121, Wallis & Futuna; J, paratype, CW 12.0 mm, MNHN IU-2017-9123, Wallis & Futuna; E–F, paralectotype, MNHN-IU-2008-10646, CW ~15–16 mm, Java; G, CW 15.2 mm, ZRC 2020.0288, Singapore; H, CW 17.5 mm, NCHUZOOL 14636; I, CW 12.5 mm, QM W19270. Scale bars: A–D = 2.0 mm; G–J = 0.5 mm.

Fig. 7. Carapaces of male Austruca perplexa (H. Milne Edwards, 1852) (A–C, F, G) and A. citrus n. sp. (D, E, H). A, male, CW 17.3 mm (NCHUZOOL 15046), Kuching, Sarawak, Malaysia; B, male, CW 12.5 mm (QM W19270), Queensland, Australia; C, male, CW 12.0 mm (ZRC 1995.966), Queensland, Australia; D, male, CW 12.7 mm (MNHN-IU-2017-9123), Wallis & Futuna; E, male, CW 11.0 mm (UF 1488), Fiji; F, female, CW 13.7 mm (NCHUZOOL 14643), Tainan, Taiwan; G, female, CW 11.3 mm (NCHUZOOL 15052), Selangor, Malaysia; H, female, CW 11.7 mm (MNHN-IU-2017-9122), Wallis & Futuna.

Fig. 8. Major chelae of Austruca perplexa (H. Milne Edwards, 1852) (A–D) and A. citrus n. sp. (E–H). A, CW 17.3 mm (NCHUZOOL 15046), Kuching, Sarawak, Malaysia; B, CW 14.9 mm (NCHUZOOL 15058), Singapore; C, CW 12.5 mm (QM W19270), Queensland, Australia; D, CW 12.0 mm (ZRC 1995.966), Queensland, Australia; E, CW 12.7 (SMF 5675), Samoa; F, CW 12.0 mm (MNHN-IU-2017-9123), Wallis & Futuna; G, CW 11.6 mm (UF 1488), Fiji; H, CW 11.0 mm (UF 1488), Fiji.

Fig. 9. Urocardiac ossicles of Austruca perplexa (H. Milne Edwards, 1852) (A–C) and A. citrus n. sp. (D). A, male, CW 13.6 mm (NCHUZOOL 15056), Mersing, Malaysia; B, male, CW 14.2 mm (NTOU), Taitung, Taiwan; C, male, CW 12.5 mm (QM W19270), Queensland, Australia; D, male, CW 11.1 mm (MNHN-IU-2017-9122), Wallis & Futuna. Scale bars = 0.2 mm.

Fig. 10. Austruca perplexa (H. Milne Edwards, 1852). A–F, male; G–H, female. A, E, CW 14.9 mm (NCHUZOOL 15057), Singapore; B, CW 12.0 mm (NCHUZOOL 15042), Bohol, Philippines; C, specimen not collected, Penghu, Taiwan; D, H, specimens not collected, Dongsha, Taiwan; F, CW 12.0 mm (NCHUZOOL 15060), Bali, Indonesia; G, CW 9.7 mm (NCHUZOOL 15050), Kuching, Sarawak, Malaysia.

Fig. 1. Collection sites for specimens of Austruca citrus n. sp. and A. perplexa (H. Milne Edwards, 1852) used in this study: blue solid squares (nos. 1–3) for A. citrus and pink solid circles (nos. 4–33) for A. perplexa (see Table 1). Blue empty square and pink empty circles indicate additional records of the two species from other references (see synonymy under A. perplexa). Different lines indicate the updated ranges of the two species.

Fig. 4. Holotype of Austruca citrus n. sp. (MNHN-IU-2017-9121; CW 10.9 mm). A, dorsal view; B, major chela; C, pleon and telson; D, third maxillipeds. Scale bars: A, B = 5.0 mm; C, D = 2.0 mm.

Fig. 11. Austruca citrus n. sp.A–E, male; F, female.A, CW 11.1 mm (MNHN-IU-2017-9122), Wallis & Futuna; B–F, specimens not collected, Fiji. G– H, a population with high density. B, G, courtesy of Mark Rosenstein; C–F, H, courtesy of Rocio Gajon Bunker.

Fig. 12. Color in life of Austruca citrus n. sp. (male, CW 14.6 mm, ZRC 2019.1317) from Fiji (A, B) and its habitat in Denarau mangroves, Nadi, Fiji (C). A, dorsal view; B, frontal view. Courtesy of Bee Yan Lee.