) and JOSEPH POUPIN 2,3 ) 1 ) 11 rue Saladin, F-97480 Saint-Joseph, La Réunion, France 2 ) École Navale, BCRM de Brest, CC 600, Lanvéoc, F-29240 Brest, France

The gecarcinids of the genus Epigrapsus are terrestrial crabs of the tropical Indo-West Pacific, with only two species currently accepted [START_REF] Ng | Systema Brachyurorum: part 1. An annotated checklist of extant brachyuran crabs of the world[END_REF][START_REF] Naruse | Size-associated morphological changes in Epigrapsus notatus (Heller, 1865) and the taxonomic status of E. villosus Ng, 2003 (Crustacea: Decapoda: Brachyura: Gecarcinidae)[END_REF][START_REF] Sasaki | The species list of Decapoda, Euphausiacea, and Stomatopoda, all of the world[END_REF]: Epigrapsus politus Heller, 1862, type locality Tahiti, and Epigrapsus notatus (Heller, 1865), type locality Nicobar Islands. These crabs are the smallest gecarcinids, carapace width (CW) being usually no more than 2-3 cm. They occupy a narrow coastal band, a few metres above the supratidal level. Although being probably common in the Indo-West Pacific, they are rarely reported because of a lack of interest in these crabs as human food, and their discreet way of life, remaining hidden under stones or vegetation during daytime. Here, we report for the first time the presence of E. politus on Réunion Island, a significant geographic range extension of this species in the Western Indian Ocean (WIO).

Epigrapsus crabs have been searched in Réunion Island during two dedicated land investigations at the stations mapped on fig. 1. A first investigation was made by the second author (JP) in March-April 2008 on the southwestern coast, between Saint Gilles-Les-Bains and Saint Joseph (fig. 1, circles; details of stations in Poupin, 2009: 116, Annexe 1, stations 1, 2, 6, 7, 10, 14, 16). A second investigation was made in November 2019 on the same coast by the first author (NH) between Saint-Leu and Saint-Philippe (fig. 1, squares) with 8 stations visited (from north to south): (1) Pointe au Sel, (2) Terre Sainte, (3) Grand Bois, (4) Grande Anse, (5) Manapany-Les-Bains, (6) Pointe Cayenne to (7) Piton Babet, and (8) Pointe Marine Vincendo. Epigrapsus crabs were found only during the second investigation and only at Manapany-Les-Bains (fig. 1, black square, 5). A dozen crabs were seen in that place during three successive visits. Two 3 ) Corresponding author; e-mail: joseph.poupin@ecole-navale.fr The crabs were identified as E. politus, based on morphological characters presented in Ng et al. (1988, table 1) and in the key to Japanese Gecarcinidae in [START_REF] Ng | Presence of the land crab, Epigrapsus politus Heller (Decapoda, Brachyura, Gecarcinidae) in Japan and Christmas Island, with a key to the Japanese Gecarcinidae[END_REF], including: (a) carapace poorly convex with posterolateral margins converging towards posterior carapace (fig. 2a,b); (b) single low epibranchial notch (fig. 3b); (c) ambulatory legs stout without setae on meri, carpi, propodi (fig. 2a); (d) small size, larger specimen being 15.3 × 18.7 mm while the largest E. notatus can reach 29.6 × 36.4 mm (Ng et al., 1988). The specimens examined also match well with high definition macro photographs examined for several specimens of E. politus collected by JP at Moorea, French Polynesia (10/x/2008) and deposited in the Florida Museum of Natural History, Gainesville, FL (FLMNH, UF15715-718).

Epigrapsus politus resembles, and has been sometimes confused with, Cyclograpsus integer H. Milne Edwards, 1837, also collected at Manapany-Les-Bains by the first author (NH). The latter is distinguished by: (a) a smaller size (CW At Manapany-Les-Bains, specimens of Epigrapsus politus were seen about 5 m far from the higher sea level on a very limited place, staying on a wet earthy ground under pebbles that were covered with creeping vine, Convolvulaceae (Ipomoea pes-caprae (L.) R. Br., 1818) and grass (fig. 3). The associated fauna includes unidentified insects (crickets and ants) and a gastropod of the family Ellobiidae (Melampus sp.), rarely found in Réunion and perhaps part of the crab's diet? Terrestrial decapods commonly associated to the same biotope in Réunion [START_REF] Poupin | Crustacés de la Réunion, Décapodes et Stomatopodes[END_REF] are Coenobita rugosus H. Milne Edwards, 1837, Geograpsus crinipes [START_REF] Dana | Grapsoidea. Conspectus Crustaceorum quae in Orbis Terrarum circumnavigatione, Carolo Wilkes e Classe Reipublicae Foederatae Duce, lexit et descripsit[END_REF] and G. grayi (H. Milne Edwards, 1853). The crabs were seen only during daytime (around 5 p.m.) by fine weather and calm sea, and not during other visits made at night or with bad weather with rough sea and big swell. They are probably not recent settlers in Réunion, because already observed in 2016 at the same station but not identified at that time (NH, field notes). Epigrapsus politus seems, however, uncommon on the island and was not retrieved in any others places prospected in 2019, despite careful attention paid to its preferred biotope.

The taxonomic history and previous geographic records of Epigrapsus species are recapitulated herein, limited to contributions where specimens were examined and/or with photographs. A few unpublished records are also included for the first time for E. politus from G. Paulay and students' collections in the western and central Pacific (FLMNH, 2020). All these places of observations are mapped on fig. 4.

Epigrapsus politus Heller, 1862

Epigrapsus politus Heller, 1862: 522, French Polynesia (Tahiti). Nectograpsus politus Heller, 1865: 57, pl. 5 fig. 3 from Christmas Is (fig. 4). For the time being this is the only WIO place where the crab has been found. No other record has been retrieved despite a thorough search in previously published contributions (mentioning Gecarcinidae) for the following places: central and western India [START_REF] Trivedi | An annotated checklist of the marine brachyuran crabs (Crustacea: Decapoda: Brachyura) of India[END_REF] without Andaman & Nicobar); Seychelles (Haig, 1984); Red Sea (Holthuis, 1977); Somalia [START_REF] Vannini | Researches on the coast of Somalia. The shore and the dune of Sar Uanle. 31. Ocypodidae and Gecarcinidae (Decapoda, Brachyura)[END_REF]; Mozambique and South Africa (Türkay, 1973b;Emmerson, 2016); Comoros (Fourmanoir, 1954), Mayotte [START_REF] Bouchard | Land, mangrove and freshwater decapod crustaceans of Mayotte region (Crustacea, Decapoda)[END_REF], Scattered Is. (Poupin et al., 2013a-b;[START_REF] Poupin | First inventory of the Crustacea (Decapoda, Stomatopoda) of Juan de Nova Island with ecological observations and comparison with nearby islands in the Mozambique Channel (Europa, Glorieuses, Mayotte)[END_REF][START_REF] Poupin | The crabs from Mayotte Island (Crustacea, Decapoda, Brachyura)[END_REF], and Madagascar [START_REF] Türkay | Die Gecarcinidae Asiens und Ozeaniens (Crustacea: Decapoda)[END_REF].

The discreet way of life of Epigrapsus politus suggests, however, that it has been potentially overlooked in other WIO places. It could probably be discovered in the future in neighbouring islands such as Mauritius, Rodrigues, Madagascar, Scattered Is., Mayotte, and Comoros, when its preferred biotope is more carefully investigated. In Mayotte, for example, [START_REF] Bouchard | Land, mangrove and freshwater decapod crustaceans of Mayotte region (Crustacea, Decapoda)[END_REF] have reported the sesarmid crab Metasesarma obesum [START_REF] Dana | Grapsoidea. Conspectus Crustaceorum quae in Orbis Terrarum circumnavigatione, Carolo Wilkes e Classe Reipublicae Foederatae Duce, lexit et descripsit[END_REF], another discreet species that has been shown to co-occur with E. politus in Okinawa [START_REF] Osawa | Epigrapsus politus Heller, 1862 (Crustacea: Decapoda: Brachyura: Gecarcinidae) from Okinawa Island, the Ryukyu Islands, with note on its habitat[END_REF]. This suggests that E. politus is perhaps also present in Mayotte. Mozambique, 1: 1-590; 2: 1-650; 3: 1-720

Fig. 1 .

 1 Fig. 1. Places prospected for Epigrapsus crabs around La Réunion in 2008 (white circles, unnumbered) and 2019 (squares, 1 to 8). Epigrapsus politus Heller, 1862 was found only at Manapany-Les-Bains (black square, 5). specimens were collected for morphological observations: 1 male 13.7 × 16.2 mm (carapace length × CW) (fig. 2), and 1 female 15.3 × 18.7 mm. After observations and macro photographs, they have been deposited and registered in the collection of the Muséum national d'Histoire naturelle, Paris (MNHN-IU-2013-7280). The crabs were identified as E. politus, based on morphological characters presented in Ng et al. (1988, table 1) and in the key to Japanese Gecarcinidae in Ng et al. (2000), including: (a) carapace poorly convex with posterolateral margins converging towards posterior carapace (fig. 2a, b); (b) single low epibranchial notch (fig. 3b); (c) ambulatory legs stout without setae on meri, carpi, propodi (fig. 2a); (d) small size, larger specimen being 15.3 × 18.7 mm while the largest E. notatus can reach 29.6 × 36.4 mm(Ng et al., 1988). The specimens examined also match well with high definition macro photographs examined for several specimens of E. politus collected by JP at Moorea, French Polynesia (10/x/2008) and deposited in the Florida Museum of Natural History, Gainesville, FL (FLMNH, UF15715-718).Epigrapsus politus resembles, and has been sometimes confused with, Cyclograpsus integer H. Milne Edwards, 1837, also collected at Manapany-Les-Bains by the first author (NH). The latter is distinguished by: (a) a smaller size (CW

Fig. 2 .

 2 Fig. 2. Habitus of Epigrapsus politus Heller, 1862, male 13.7 × 16.2 mm (MNHN-IU-2013-7280): a, whole animal, dorsal view; b, carapace dorsal view with indication of low epibranchial notch (arrow); c, cephalothorax, frontal view; d, ventral view with aspect of male abdomen. Scale bar: a, 10 mm; b, c, d, 5 mm.

Fig. 4 .

 4 Fig. 4. Geographic distributions of Epigrapsus politus Heller, 1862 (circles) and E. notatus (Heller, 1865) (squares). New recorded places for E. politus are in italics, with grey spots, from west to east: Réunion, Palawan, Panglao, Palau, Yap, Palmyra, and Raiatea. Black lines indicate distances (in km) between Réunion and previous records in the central (Chagos Is.) and eastern (Christmas Is.) Indian Ocean. The dashed rectangle indicates the known geographic range of E. notatus.

  J. G., 1887. Carcinological studies in the Leyden Museum. No 3. Notes from the Leyden Museum, 5: 150-169. DE MAN, J. G., 1895. Bericht über die von Herrn Schiffscapitän Storm zu Atjeh, an den westlichen Küsten von Malakka, Borneo und Celebes sowie in der Java-See gesammelten Decapoden und Stomatopoden. Zweiter Theil. Zoologische Jahrbücher, (Abtheilung für Systematik, Geographie und Biologie der Thiere) 9(1): 75-218. EMMERSON, W. D., 2016. A guide to, and checklist for, the Decapoda of Namibia, South Africa and

  B., 1977. The Grapsidae, Gecarcinidae and Palicidae (Crustacea: Decapoda: Brachyura) of the Red Sea. Israel Journal of Zoology, 26: 141-192. LEE, J.-H., 2001. A field guide to crabs in Taiwan: 1-174. (Bigtrees Co., Taipei). [In Chinese.] LIU, H.-C. & M.-S. JENG, 2005. Reproduction of Epigrapsus notatus (Brachyura: Gecarcinidae) in Taiwan. Journal of Crustacean Biology, 25(1): 135-140. MIERS, E. J., 1877. On a collection of Crustacea made by rev. G. Brown, C.M.Z.S. on Duke of York Island. Proceedings of the Zoological Society of London, 1877: 133-138. MIERS, E. J., Report on the Brachyura collected by H.M.S. Challenger during the years 1873-1876. Report on the Scientific Results of the Voyage of H.M.S. Challenger, Zoology, part 49, 17(2): 1-362, pls. 1-29.

  , French Polynesia (Tahiti).

	Epigrapsus politus -Miers, 1886: 266, Vanuatu (Api =? Epi Is.). -Ortmann, 1894: 703, Fiji,
	Papua New Guinea (Kaiser WilhelmsLand). -De Man, 1895: 79, Indonesia (Atjeh = Aceh,
	Sumatra), Micronesia (Ponape = Pohnpei). -Alcock, 1900: 444, Andaman and Nicobar. -
	Rathbun, 1902: 126, Maldives (Fadiffolu Atoll). -Tesch, 1918: 133, Indonesia, Flores Sea

(Tanah-Djampeah = Pulau Tanahjampea Is.)

.

-Sendler, 1923: 26, fig. 1, Papua New Guinea (Bertrand Island = Tarawai Is.)

.

[START_REF] Ward | Notes on the Crustacea of the Desjardins Museum, Mauritius Institute, with descriptions of new genera and species[END_REF]: 51, 108, Chagos archipelago (Salomon Atoll). - Holthuis, 1953: 34, Marshall

Islands (Arno Atoll), Society Islands, Tahiti (Taravao).

-Forest & Guinot, 1961: 162, fig. 176, Indonesia (Atjeh)

, Tuamotu (Hikueru).

-Türkay, 1974: 248, figs. 7, 18, Sumatra (Atjeh)

, Papua New Guinea (Bertrand Is.), Micronesia (Ponape = Pohnpei), Society (Tahiti; types), Tuamotu (Hikueru).

-Tavares, 1989: 36, Tahiti (types)

.

-Poupin,

  1994: 55, fig. 51, pl. 6d, Tuamotu (Hikueru), Indonesia (Atjeh). -Ng et al., 1998: 82, Tahiti (types), Papua New Guinea (Bertrand Is. = Tarawai Is.). -Ng et al., 2000: 380, Christmas Is., Japan (Ryukyus), Papua New Guinea (Bertrand Is.), Tahiti (types). -Cuesta et al.

	, 2002:
	1672, Indonesia (Sulawesi), Taiwan (Pingtung, Hsiang-Chiao-Wan). -Osawa & Fujita, 2005:
	59, Japan (Okinawa). -Orchard, 2012: 152, Christmas Is. (colour photos). -Guinot et al.,
	2013: 284, Indonesia (Atjeh). -Shih, 2013: 110, Dongsha Island (colour photos). -Hartnoll et
	al., 2017: 933, fig. 5, Society (Moorea), Micronesia (Ponape = Pohnpei), Indonesia (Sumatra). -
	Ng et al., 2017: 97, fig. 10e-f (comprehensive references for Taiwan; colour photos). -Guinot
	et al., 2018: 551, Indonesia (Atjeh). -Naruse et al., 2018: 210, tab. 1, Philippines (Cebu,
	Kawasan), Taiwan. -Sasaki, 2019: 12684 (taxonomy and comprehensive references). -Toyota
	et al., 2019: 192-193, Ryukyus (Okinawa Is.; colour figs.). -FLMNH, 2020, additional museum
	collections in: Philippines (Panglao, UF8899, Palawan, UF8844), Palau (Ngarchelong, UF4995),
	Micronesia (Yap, UF2355), Line Islands (Palmyra Atoll, UF10591, 10875), Society Island
	(Raiatea, UF2221; Moorea, UF1434, 1521, 15715-718, 10086, 34900; Tahiti, UF1406, 2215).

  . (Cambridge Scholars Publishing, Newcastle upon Tyne). FLMNH, 2020. Florida Museum of Natural History, invertebrate zoology collection. Available online at http://specifyportal.flmnh.ufl.edu/iz/ [Consulted 2020.] FOREST, J. & D. GUINOT, 1961. Crustacés Décapodes Brachyoures de Tahiti et des Tuamotu. In: Expédition française sur les récifs coralliens de la Nouvelle Calédonie. Volume préliminaire, 9-11: 1-195, pls. 1-18. (Editions de la Fondation Singer Polignac, Paris). FOURMANOIR, P., 1954. Crabes de la côte ouest de Madagascar. Le Naturaliste Malgache, 6(1/2): 1-16. GUINOT, D., N. K. NG & P. A. RODRÍGUEZ MORENO, 2018. Review of grapsoid families for the establishment of a new family for Leptograpsodes Montgomery, 1931, and a new genus of Gecarcinidae H. Milne Edwards, 1837 (Crustacea, Decapoda, Brachyura, Grapsoidea MacLeay, 1838). Zoosystema, 40(26): 547-604. GUINOT, D., M. TAVARES & P. CASTRO, 2013. Significance of the sexual openings and supplementary structures on the phylogeny of brachyuran crabs (Crustacea, Decapoda, Brachyura), with new nomina for higher-ranked podotreme taxa. Zootaxa, 3665(1): 1-414. HAIG, J., 1984. 7. Land and freshwater crabs of the Seychelles and neighbouring islands. In: D. R. Die Crustaceen. Reise der österreichischen Fregatte Novara um die Erde in den Jahren 1857-1859 unter den Befehlen des Commodore B. von Wüllerstorf-Urbair. Zoologischer Theil. Zweiter Band. III. Abteilung: 1-280, pls. 1-25. (Kaiserliche Akademie der Wissenschaften, Vienna). HILGENDORF, F., 1888. Bemerkungen über die Morphologie der Augenhohle von Gecarcinus und über eine neue verwandte Gattung Mystacocarcinus. Sitzungsberichte der Gesellschaft Naturforschender Freunde zu Berlin, 1888: 26-29. HOLTHUIS, L. B., 1953. Enumeration of the decapod and stomatopod Crustacea from Pacific coral islands. Atoll Research Bulletin, 24: 1-66. HOLTHUIS, L.

	STODDART (ed.), Biogeography and ecology of the Seychelles Islands: 123-139. (Dr. W. Junk
	Publishers, The Hague, Boston, Lancaster).
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	of mature males of the land crabs Johngarthia lagostoma and Epigrapsus spp. Crustaceana,
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	HELLER, C., 1862. Neue Crustaceen, gesammelt während der Weltumseglung der k.k. Fregatte
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	HELLER, C., 1865.

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ACKNOWLEDGEMENTS G. Paulay, University of Florida, and his students, J. Starmer, C. McKeon and H.-C. Liu, are thanked for giving permission to use of their unpublished observations of Epigrapsus politus in several places of the western and central Pacific (Philippines, Palau, Micronesia, Line Islands, and Society Islands).

Epigrapsus notatus (Heller, 1865) Grapsodes notatus Heller, 1865: 58, pl. 5 fig. 2, Nicobar. -Miers, 1877: 136, Papua New Guinea (Duke of York Is.). -De Man, 1887: 160, Indonesia, Moluccas (Morotai Is.). -Alcock, 1900: 442, Nicobar. Mystacocarcinus crenidens Hilgendorf, 1888: 29, Bismarck Archipelago (New Ireland, Carteret 'Harbour' =? Carteret Is.) Epigrapsus (Grapsodes) notatus -Sendler, 1923: 27, fig. 2, pl. 5(20) photos 3, Papua New Guinea (Bertrand Is. = Tarawai Is.). Epigrapsus (Grapsodes) notatus punctatus Sendler, 1923: 28, Papua New Guinea (Bertrand Is. = Tarawai Is.; Liebliche Is. = Arawa Is.). Epigrapsus (Grapsodes) wolfi Sendler, 1923: 28, fig. 3, pl. 6(21) photos 4, Papua New Guinea (Lamassa). Epigrapsus villosus Ng, 2002: 1220, figs. 1-3, Guam. -Ng et al., 2008, 215, fig. 160, Vanuatu. Epigrapsus sp. 1 (n. sp., Ng) - Paulay et al., 2003: 494, Guam (type of E. villosus). Epigrapsus notatus -Tesch, 1918: 134, Indonesia, 'Talaut' = Talaud Is. (Lirung). -Sakai, 1955: 200, Japan (Hachijo Is.). -Türkay, 1973a: 105, figs. 1, 3, Nicobar (type of E. notatus), figs. 2, 4, 5-6, Papua New Guinea (type of E. wolfi). -Türkay, 1974: 251, figs. 6, 9, 19, Nicobar, Indonesia (Talaud Is.), Papua New Guinea (Bertrand Is. = Tarawai Is., type of E. punctatus; Lamassa, New Ireland; St. Matthias = Mussau Is.; Liebliche Is. = Arawe Is.; Admiralty Is. = Manus Is.), Salomon (Steward Is.); Japan (Bonin Is. = Ogasawara Is.). -Sakai, 1976: 678, fig. 373, Japan (Hachijo Is.). -Türkay, 1977: 157, Carteret 'Harbour' =? Carteret Is., type of Mystacocarcinus crenidens). -Tavares, 1989: 36, Indonesia (western Sumatra), Papua New Guinea (Bismarck Archipelago). -Takeda, 1994: 218, colour photo 5, Ryukyus (Ishigaki Is.). -Ng et al., 1998: 72, figs. 1-5, Taiwan (fig. 3, colour photo). -Ng et al., 2000: 379, Ryukyus (Ishigaki Is.), 380, Papua New Guinea (Nagada). -Lee, 2001: 141, Taiwan (colour photo). -Cuesta et al., 2002: 1672, Taiwan (Hengchun, Hualien). -Ng, 2002: 1224, Guam. -Paulay et al., 2003: 494, Guam. -Liu & Jeng, 2005: 135, Taiwan (Hengchun). -De Grave et al., 2009: 109, fig. 7G, Taiwan (colour photo). -Shih, 2013: 108, Dongsha Is. (colour photos). -Hartnoll et al., 2017: 933, Taiwan (Kenting). -Ng et al., 2017: 97 (comprehensive references for Taiwan). -Guinot et al., 2018: 551, Taiwan (Hsiang-Chiao-Wan). -Naruse et al., 2018: 210-212, tab. 1, Indonesia (west Java), Philippines (Cagayan, Palaui Is.), Taiwan, Japan (Ryukyus), Guam (including type of E. villosus), Vanuatu. -Sasaki, 2019: 12683 (taxonomy and comprehensive references). - Toyota et al., 2019: 190-191, Ryukyus (Ishigaki Is.; colour figs.).

The new record of Epigrapsus politus in Réunion significantly extends its geographic range in the WIO, 2500 km away from Chagos Is. and 5500 km far

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