A new alpheid shrimp genus, Crosnierocaris gen. nov., is established for Crosnierocaris athanasoides sp. nov., a very peculiar shrimp possibly associated with decomposing sea grass accumulations in deeper water. The type series of C. athanasoides sp. nov. was collected in the Mozambique Channel, north of Grande Glorieuse Island, at a depth of 240–255 m. The new genus presents a unique combination of morphological features, including the very long, slender rostrum armed with a subdistal ventral tooth; the pterygostomial angle projecting as a strong sharp tooth; the third to fifth pleura with their distoventral margins armed with two to four small teeth, a unique feature within the Alpheidae; the sixth pleuron with an articulated plate; the eyes largely exposed dorsally and laterally; the first pereiopods (chelipeds) feebly enlarged in both sexes, stouter but shorter than walking legs; the first pereiopod carpus with rows of short serrulate setae on its mesial surface; the second pereiopod carpus with five subdivisions; the third to fifth pereiopods with meri armed with stout cuspidate setae; the uropodal diaeresis with a strongly dentate lateral portion; and the complete gill-exopod formula, with mastigobranchs on coxae of the third maxilliped and first to fourth pereiopods. Within alpheid shrimps, the rostrum of C. athanasoides sp. nov. is one of the longest relative to the total body length, often reaching half of the carapace length. The phylogenetic position of Crosnierocaris gen. nov. within the Alpheidae remains to be determined, but based on its morphological characters, the new genus appears to be closest to Athanas Leach, 1814, especially in the configuration of the frontal area of the carapace, and Potamalpheops Powell, 1979, for instance, in the armature of the uropodal diaeresis and walking legs, as well as the presence of setal rows on the cheliped carpus. The new genus also shares several morphological features with Yagerocaris Kensley, 1988, which represents one of the least derived lineages within the family Alpheidae.
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 (1), 61–68. https://doi.org/10.11646/zootaxa.3154.1.5
Anker, A. (2003) Alpheid shrimps from the mangroves and mudflats of Singapore. Part I. Genera Salmoneus, Athanas and Potamalpheops, with the description of two new species (Crustacea: Decapoda: Caridea). Raffles Bulletin of Zoology, 51, 283–314.
Anker, A. (2010) A new genus and three new species of alpheid shrimps (Crustacea, Decapoda, Caridea) from the tropical American coasts. Zootaxa, 2652 (1), 47–63. https://doi.org/10.11646/zootaxa.2652.1.4
Anker, A., Ahyong, S.T., Palmer, A.R. & Noël, P.Y. (2006a) 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., Poddoubtchenko, D. & Jeng, M.S. (2006b) Acanthanas pusillus, new genus, new species, a miniature alpheid shrimp with spiny eyes from the Philippines (Crustacea: Decapoda). Raffles Bulletin of Zoology, 54, 341–348.
Anker, A. & Jeng, M.S. (2007) Establishment of a new genus for Arete borradailei Coutière, 1903 and Athanas verrucosus Banner and Banner, 1960, with redefinition of Arete Stimpson, 1860 and Athanas Leach, 1814 (Crustacea: Decapoda: Alpheidae). Zoological Studies, 46, 454–472.
Banner, A.H. & Banner D.M. (1960) Contributions to the knowledge of the alpheid shrimp of the Pacific Ocean. Part V. The Indo-Pacific members of the genus Athanas. Pacific Science, 14, 129–155.
Banner, D.M. & Banner, A.H. (1973) The alpheid shrimp of Australia. Part I: the lower genera. Records of the Australian Museum, 28, 291–382. https://doi.org/10.3853/j.0067-1975.28.1973.407
Bruce, A.J. (1983) Pseudathanas darwiniensis, new genus, new species, an alpheid shrimp from the Northern territory, Australia. Journal of Crustacean Biology, 3, 463–471. https://doi.org/10.2307/1548146
Chace, F.A. Jr. & Kensley, B. (1992) The cardiac notch in decapods. Journal of Crustacean Biology, 12, 442–447. https://doi.org/10.2307/1549038
Chow, L.H., De Grave, S., Anker, A., Poon, K.K.Y., Ma, K.Y., Chu, K.H., Chan, T.Y. & Tsang, L.M. (2021) Distinct suites of pre- and post-adaptations indicate independent evolutionary pathways of snapping claws in the shrimp family Alpheidae (Decapoda: Caridea). Evolution, 75 (11), 2898–2910. https://doi.org/10.1111/evo.14351
Christodoulou, M., Iliffe, T.M. & De Grave, S. (2019) A new anchialine cave dwelling species of Potamalpheops Powell, 1979 from the Solomon Islands (Crustacea, Decapoda, Alpheidae). Crustacean Research, 48, 11–21. https://doi.org/10.18353/crustacea.48.0_11
Coutière, H. (1897) Note sur un nouveau genre d’alphéidés. Bulletin du Muséum d’Histoire Naturelle, 1 (3), 301–303. https://doi.org/10.5962/bhl.part.19260
De Grave, S., Park, J.H. & Anker, A. (2020) A redescription of Salmoneus tafaongae Banner & Banner, 1966 (Malacostraca: Decapoda: Alpheidae). Crustacean Research, 49, 173–186. https://doi.org/10.18353/crustacea.49.0_173
De Man, J.G. (1911) The Decapoda of the Siboga-Expedition, II: Family Alpheidae. Siboga-Expeditie, 39 a1 (2), 133–465. https://doi.org/10.5962/bhl.title.10512
Hayashi, K.I. (2002) A new species of the genus Athanas (Decapoda, Caridea, Alpheidae) living in the burrows of a mantis shrimp. Crustaceana, 75, 395–403. https://doi.org/10.1163/156854002760095462
Hobbs, H.H. Jr. (1983) The African shrimp genus Potamalpheops in Mexico (Decapoda: Alpheidae). Crustaceana, 44, 221–224. https://doi.org/10.1163/156854083X00848
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, Leiden, 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
Leach, W.E. (1813–1814) Crustaceology. In: Brewster, D. (Ed.), The Edinburgh Encyclopædia. A. Balfour, Edinburgh, pp. 383–437.
Powell, C.B. (1979) Three alpheid shrimps of a new genus from West African fresh and brackish waters: taxonomy and ecological zonations (Crustacea, Decapoda, Natantia). Revue de Zoologie Africaine, 93, 116–150.
Spence Bate, C. (1888) Report on the Crustacea Macrura dredged by H.M.S. Challenger during the years 1873–76. In: The voyage of H.M.S. Challenger. Zoology. Vol. 24. Eyre & Spottiswoode, London, pp. i–xi + 1–942, pls. 1–157. [separate volume]
Soledade, G.O., Santos, P.S. & Almeida, A.O. (2014) Potamalpheops tyrymembe sp. n.: the first southwestern Atlantic species of the shrimp genus Potamalpheops Powell, 1979 (Caridea: Alpheidae). Zootaxa, 3760 (4), 579–586. https://doi.org/10.11646/zootaxa.3760.4.7
Yeo, D.C.J. & Ng, P.K.L. (1997) The alpheid shrimp genus Potamalpheops Powell, 1979 (Crustacea: Decapoda: Caridea: Alpheidae) from Southeast Asia, with descriptions of three new species. Journal of Natural History, 31, 163–190. https://doi.org/10.1080/00222939700770111