Abstract
Two species of alpheid shrimp collected from a marine cave off Ie Island, Okinawa Islands, Ryukyu Islands, Japan, are reported. Caligoneus cavernicola n. gen., n. sp., is described on the basis of six specimens, including two ovigerous individuals. The new monotypic genus shares a number of features with Salmoneus Holthuis, 1955 and Triacanthoneus Anker, 2010; however, the dorsally elevated rostrum and the symmetrical pereopods 1 (= chelipeds) of “minor form” distinguish Caligoneus n. gen. from the latter two genera. Other potentially diagnostic characters between the new genus and the latter two genera are also discussed. The new taxon is clearly adapted to stygobiotic environments, with its reduced cornea and very slender elongate pereopods. In addition, two complete specimens of Salmoneus antricola Komai, Yamada & Yunokawa, 2015, collected in the same cave, supplement the original description of the species, which was based on a unique holotype with a damaged telson.
References
Alvarez, F., Iliffe, T.M., Gonzalez, B. & Villalobos, J.L. (2012) Triacanthoneus akumalensis, a new species of alpheid shrimp (Crustacea: Caridea: Alpheidae) from an anchialine cave in Quintana Roo, Mexico. Zootaxa, 3154, 61–68.
Alvarez, F., Iliffe, T.M. & Villalobos, J.L. (2014) A new species of the alpheid shrimp genus Triacanthoneus Anker, 2010 (Crustacea: Alpheidae) from Belize. Zootaxa, 3768 (1), 88–94.
https://doi.org/10.11646/zootaxa.3768.1.6
Anker, A. (2007) New species and records of alpheid shrimps, genera Salmoneus Holthuis and Parabetaeus Coutière, from the tropical western Atlantic (Decapoda, Caridea). Zootaxa, 1653, 21–39.
Anker, A. (2008) A worldwide review of stygobiotic and stygophilic shrimps of the family Alpheidae (Crustacea, Decapoda, Caridea). Subterranean Biology, 6, 1–16.
Anker, A. (2010a) The shrimp genus Salmoneus Holthuis, 1955 (Crustacea, Decapoda, Alpheidae) in the tropical western Atlantic, with description of five new species. Zootaxa, 2372, 177–205.
Anker, A. (2010b) A new genus and three new species of alpheid shrimps (Crustacea, Decapoda, Caridea) from the tropical American coasts. Zootaxa, 2652, 47–63.
Anker, A. (2011) Three new species of the alpheid shrimp genus Salmoneus Holthuis, 1955 (Crustacea, Decapoda) from the tropical western Pacific. Zootaxa, 2839, 67–84.
Anker, A., Ahyong, S.T., Noël, P.Y. & Palmer, A.R. (2006) Morphological phylogeny of alpheid shrimps: parallel preadaptation and the origin of a key morphological innovation, the snapping claw. Evolution, 60, 2507–2528.
https://doi.org/10.1111/j.0014-3820.2006.tb01886.x
Anker, A. & Fujita, Y. (2014) On the presence of the anchialine shrimp Calliasmata pholidota Holthuis, 1973 (Crustacea: Decapoda: Caridea: Barbouriidae) in Shimoji Island, Ryukyu Islands, Japan. Fauna Ryukyuana, 17, 7–11.
Anker, A. & Marin, I.M. (2006) New records and species of Alpheidae (Crustacea, Decapoda) from Vietnam. Part I. Genus Salmoneus Holthuis, 1955. Raffles Bulletin of Zoology, 54, 295–319.
Banner, D.M. & Banner, A.H. (1973) The alpheid shrimp of Australia. Part 1: Lower genera. Records of the Australian Museum, 28, 291–382.
https://doi.org/10.3853/j.0067-1975.28.1973.407
De Grave, S., Chan, T.-Y., Fujita, Y. & Okuno, J. (2012) Hippolytidae and Barbouriidae (Decapoda: Caridea) collected during the Ryukyu “KUMEJIMA 2009” expedition. Zootaxa, 3367, 95–102.
Fujita, Y. & Naruse, T. (2011) Catoptrus iejima, a new species of cavernicolous swimming crab (Crustacea: Brachyura: Portunidae) from a submarine cave at Ie Island, Ryukyu Islands, Japan. Zootaxa, 2918, 29–38.
Fujita, Y. & Mizuyama, M. (2016) New distributional record of Atoportunus gustavi Ng & Takeda, 2003 (Decapoda: Brachyura: Portunidae) from Okinawa-jima and Ie-jima Islands, Ryukyu Islands, southwestern Japan. Fauna Ryukyuana, 33, 19–20. [in Japanese with English abstract]
Holthuis, L.B. (1955) The recent genera of the caridean and stenopodidean shrimps (class Crustacea, order Decapoda, supersection Natantia) with keys for their determination. Zoologische Verhandelingen, 26, 1–157.
Kensley, B. (1988) New species and records of cave shrimps from the Yucatan Peninsula (Decapoda: Agostocarididae and Hippolytidae). Journal of Crustacean Biology, 8, 688–699.
https://doi.org/10.2307/1548704
Komai, T. & Anker, A. (2012) A distinctive new species of the alpheid genus Salmoneus Holthuis, 1955 (Crustacea: Decapoda: Caridea) from the northwestern Pacific. Zootaxa, 3344, 60–68.
Komai, T. & Fujita, Y. (2005) A new stygiobiont species of Macrobrachium (Crustacea: Decapoda: Caridea: Palaemonidae) from an anchialine cave on Miyako Island, Ryukyu Islands. Zootaxa, 1021, 13–27.
https://doi.org/10.11646/zootaxa.1021.1.2
Komai, T. & Yamada, Y. (2011) A new species of the caridean genus Bresilia Calman (Decapoda: Bresiliidae) discovered from a shallow-water submarine cave in Okinawa Islands, Japan. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement, 5, 71–82.
Komai, T., Yamada, Y. & Yunokawa, K. (2015) A new cave-dwelling species of the alpheid shrimp genus Salmoneus Holthuis, 1955 (Crustacea: Decapoda: Caridea) from the Ryukyu Islands, southern Japan. Zootaxa, 4028, 413–420.
https://doi.org/10.11646/zootaxa.4028.3.6
Miya, Y. (1972) The Alpheidae (Crustacea, Decapoda) of Japan and its adjacent waters. Part. 1. Publications from the Amakusa Marine Biological Laboratory, Kyushu University, 3, 23–101.
Naruse, T. & Fujita, Y. (2015) Lipkemera iejima, a new cavernicolous crab (Brachyura: Xanthidae) from a submarine cave at Ie Island, central Ryukyu Islands, Japan. Crustacean Research, 44, 21–27.
https://doi.org/10.18353/crustacea.44.0_21
Ng, P.K.L. & Takeda, M. (2003) Atoportunus, a remarkable new genus of cryptic swimming crab with descriptions of two new species from the Indo-West Pacific. Micronesica, 35/36, 417–430.
Weese, D.A, Fujita, Y., Hidaka, M. & Santos, S.R. (2012) The long and short of it: genetic variation and population structure of the anchialine atyid shrimp Caridina rubella on Miyako-jima, Japan. Journal of Crustacean Biology, 32, 109–117.
https://doi.org/10.1163/193724011X615389