Abstract
A field collection of Crustacea was made in the Biological Reserve of Atol das Rocas, Northeastern Brazil, from October 2000 to October 2001. Specimens were obtained from washed algae, from the inner and outer parts of the annular reef between 0–20 m depths. In this paper we describe two new species of the genus Quadrimaera Krapp-Schickel & Ruffo, 2000 (Amphipoda: Melitidae) from Atol das Rocas. Quadrimaera chaelata sp. nov. differs from all other species of the genus by a strong process in the palmar corner on the propodus of gnathopod 2 that essentially makes it chelate; Quadrimaera rocasensis sp. nov. differs from its congeners in size, shape, and order of excavations on the palm of gnathopod 2, by a robust spine on the inner margin of the dactylus of gnathopod 2 that opposes the first excavation of the palm, and by three long bifid setae and a nail with an apical seta, in each lobe of the telson. The two new species are endemic to Atol das Rocas. This study raises to three the number of known species of the genus Quadrimaera from the atoll: the two new species and Quadrimaera cristianae Krapp-Schickel & Ruffo, 2000. A key to identification for the species of Quadrimaera from Atol das Rocas is given.References
Barnard, J.L. (1976) Amphipoda (Crustacea) from the Indo-Pacific Tropics: a review. Micronesica, 12 (1), 169–181.
Edwards, A. & Lubbock, R. (1983) Marine zoogeography of St Paul’s Rocks. Journal of Biogeography, 10, 65–72.
Floeter, S.R. & Gasparini, J.L. (2000) The southwestern Atlantic reef fish fauna: composition and zoogeographic patterns. Journal of Fish Biology, 56, 1099–1114.
Joyeux, J.C., Floeter, S.R., Ferreira, C.E.L. & Gasparini, J.L. (2001) Biogeography of tropical reef fishes: the South Atlantic puzzle. Journal of Biogeography, 28, 831–841.
Kikuchi, R.K.P. (1994) Geomorfologia, estratigrafia e sedimentologia do Atol das Rocas (REBIO/IBAMA/RN), Atl>ntico sul ocidental equatorial. Master dissertation, Universidade Federal da Bahia.
Krapp, T., Marti, A. & Ruffo, S. (1996) Three new Mediterranean Maera with remarks on the Quadrimana complex (Crustacea, Amphipoda, Melitidae). Beaufortia, 46 (3), 27–51.
Krapp-Schickel, T. (2000) Pitfall genus Maera (Crustacea: Amphipoda: Melitidae). Polskie Archiwum Hydrobiologii, 47 (3–4), 413–440.
Krapp-Schickel, T. & Ruffo, S. (2000) The Maera quadrimana complex (Crustacea: Amphipoda: Melitidae) demands a new concept: Quadrimaera n. gen. (with description of three new species from Western Atlantic). Bollettino del Museo Civico di Storia Naturale di Verona, 24, 193–214.
Moraes, F.C. & Muricy, G. (2003) Taxonomy of Plakortis and Plakinastrella (Demospongiae: Plakinidae) from oceanic islands off north-eastern Brazil, with description of three new species. Journal of the Marine Biological Association of the United Kingdom, 83, 385–397.
Myers, A.A. (1985) Shallow-water, coral reef and mangrove Amphipoda (Gammaridea) of Fiji. Records of the Australian Museum, Supplement 5, 1–143.
Poore, A.G.B. & Lowry J.K. (1997) New ampithoid amphipods from Port Jackson, New South Wales, Australia (Crustacea: Amphipoda: Ampithoidae). Invertebrate taxonomy, 11, 897–941.
Ruffo, S., Krapp, T. & Gable, M.F. (2000) The genus Maera (Crustacea: Amphipoda: Melitidae) from Bermuda. Postilla, 221, 1–35.
Senna, A.R. & Serejo, C.S. (2005) Ingolfiella rocaensis sp. nov. (Crustacea: Amphipoda: Ingolfiellidea): first record of ingolfiellidean amphipods in Brazilian waters. Zootaxa, 962, 1–6.
Wakabara, Y. (1972) EspJcies da família Gammaridae (Crustacea: Amphipoda), entre as latitudes 03°23' e 38°05' S do Atlântico Ocidental. PhD thesis. Universidade de São Paulo, Instituto Oceanogr<fico, 87 p., 46 pls.
Watling, L. (1989) A classification system for crustacean setae based on the homology concept. Crustacean Issues, 6, 15–26.