A new species of Achaeus Leach , 1817 ( Decapoda : Brachyura : Majoidea : Inachidae ) from Easter Island

In the present paper, a new species of Achaeus Leach, 1817, is described from Easter Island and dedicated to the memory of Michael Türkay. Th is record represents the fi rst inachid spider crab and the sixth endemic brachyuran to be described from the island. It can be diff erentiated from congeners by its relatively short carapace, with the postorbital region not elongated, the arrangement and number of tubercles on the dorsal carapace surface, prominent hepatic lobe, presence of a large anterodistal lobe on the ocular peduncle, as well as structures of the third maxilliped and ambulatory legs. key words Crustacea, Easter Island, endemic, southeastern Pacifi c, spider crab.

family Inachidae, with 193 species in 35 genera (Ng et al., 2008), has previously been recorded or described from Easter Island.The only inachids previously known from the vicinity of the island are two deepwater species, Cyrtomaia platypes Yokoya, 1933, and Cyrtomaia danieli Zarenkov, 1990, which were reported from the adjacent Sala y Gómez and Nazca Seamounts (Zarenkov, 1990;Parin et al., 1997).
In 1998 and 1999, teams of researchers (including the second author in 1999) were assembled by Dr. John Tanacredi, then of the Gateway National Recreation Area, U.S. National Park Service, to form the Science Museum of Long Island -Easter Island Expedition of 1998-1999 in order to survey the near-shore marine environment.Recently, papers on the diversity of the island's portunoids (Boyko and Liguori, 2014), grapsoids and cryptochiroids (Boyko and Liguori, 2015) were published based, in large part, on material collected by this expedition.In the present paper, a new species of majoid belonging to the genus Achaeus Leach, 1817, is described and dedicated it to the memory of the late Michael Türkay.

Material and Methods
The holotype is deposited in the National Museum of Natural History (USNM), Smithsonian Institution, Washington D.C.The terminology used follows that in Ng & Richer de Forges (2015).Measurements provided, in millimeters, are of the maximum carapace length and width, respectively.The abbreviations P2-P5 are used for the second to fifth pereopods (first to fourth ambulatory legs), respectively.Remarks.Achaeus Leach, 1817, is a widely dispersed genus known from the eastern Atlantic, Mediterranean and Indo-West Pacific.The genus has 37 recognised species (Griffin & Tranter, 1986;Ng et al., 2008), including the type species Achaeus cranchii Leach, 1817.The present specimen from Easter Island has a combination of characters that make it different from all other Achaeus taxa and is described here as a new species.
Etymology.This species is named in memory of our friend, Prof. Dr. Michael Türkay (1948-2015) to honour his great love of gastronomy.Umu, memorably experienced first-hand by the second author during his visit in 1999, is a traditional and delicious Easter Island meal consisting of a mixture of meat, fish, vegetables and fruit wrapped in banana leaves and roasted in an earth oven (umu pae).
Ambulatory legs very long, slender; surface covered with long and short straight, curved and plumose setae;
Remarks.With regards to the short and rounded pseudorostrum, broad and prominent hepatic lobe and structure of the last ambulatory legs, A. umu n. sp.most resembles the Indo-West Pacific Achaeus lacertosus Stimpson, 1858.The latter species, however, has a smooth carapace without any tubercles (cf.Sakai, 1976: text fig.82), unlike that of A. umu n. sp.(Figs.1A, 2A).Achaeus umu n. sp. is also similar to Achaeus spinosus Miers, 1879 (Persian Gulf to Japan) but the postorbital region of the new species is short (vs.postorbital region distinctly longer in A. spinosus), the hepatic region has only one small granule in addition to the lobe (vs. the hepatic region with two or more granules in addition to the lobe in A. spinosus) and the branchial region only has three tubercles (vs. the lobe and the branchial region only has one tubercle in A. spinosus) (cf.Sakai, 1976: text fig. 85).
acknowledgeMents Thanks to Hank Tonnemacher for collecting the specimen during a dive and to John T. Tanacredi (formerly of The National Park Service and Gateway National Recreation Area, now at Molloy College, Rockville Centre, NY) for inviting the second author to participate in the 1999 expedition.Thanks are also due to various reviewers for their constructive criticisms.Funding for the Invertebrate Survey of Easter Island was provided by the U.S. National Park Service, Gateway National Recreation Area, Division of Natural Resources, as part of a Science Museum of Long Island / Explorers Club 5-year research expedition to explore the impacts of El Nino events on World Heritage Sites.

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new species of Achaeus Leach from Eastern Island Nauplius, 24: e2016019

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new species of Achaeus Leach from Eastern Island Nauplius, 24: e2016019