Furca

Abstract: During a survey of the zooplankton community of a protected reef system on the southern coast of the Mexican Caribbean, many female and male specimens of an undescribed species of Caligus Muller, 1785 were collected. The new species closely resembles C. wilsoni Delamare Deboutteville & Nunez-Ruivo, 1958 and C. belones (Kroyer, 1863) and has affinities with C. balistae Steenstrup & Lutken, 1861 and C. longipedis Bassett-Smith, 1898, all known from the Caribbean Sea and adjacent waters of the north-western Atlantic Ocean. Caligus ilhoikimi sp. nov., is described in full and illustrations of both sexes are also provided. The new species differs from C. wilsoni and C. belones in several features, including the shape of the sternal furca, the shape and proportions of the genital complex and abdomen, the lack of accessory processes on the distal elements of leg 1 exopod, and the presence of a lateral spine on the third exopodal segment of leg 2. This is the seventh species of Caligus known from waters of the Atlantic seaboard of Mexico and the 32nd species of the genus recorded in Mexican waters. The specimens were caught with a plankton light trap. The unusually high number of individuals captured and the fact that the sample was monospecific ( i.e. only adults of this caligid species were collected) suggests that it is a chiefly planktonic form. This is a mode of life recently revealed as being more common among caligids than previously thought.

Abstract: A new species of the genus Xenylla Tullberg, 1869 is described. The new species, Xenylla weinerae sp. nov., from China, resembles X. acauda Gisin, 1947, X. brevicauda Tullberg, 1869, X. caudata Jordana, 1993, X. lesnei Denis, 1935, X. nirae Gama & Oliveira, 1994, X. wandae Queiroz & Mendonca, 2016 and X. vanharteni Weiner et al., 2012 due to unique feature––six thickened cylindrical sensilla on antennal segment IV. X. weinerae sp. nov. having moderately modified chaetotaxy (b h1 h2 q t, head with dorsal setae l1 and l3 subequal, dorsal setae a3 on Abd. IV present) and well-developed furca (mucro separated from the dens, bearing 2 setae) is also similar to some populations of X. obscura Imms, 1912 sensu Thibaud et al. (2004). An identification key to Asian Xenylla species is provided.

Abstract: Herein we describe nine species of Eocyzicus from Australia and re-describe the morphological variability of Eocyzicus parooensis Richter & Timms, 2005 and Eocyzicus argillaquus Timms & Richter, 2009. All species were previously delimited by molecular phylogenetic analyses and the species descriptions are based on the same individuals. Characters were scored with the aid of the taxonomic software DELTA. The morphological analyses largely corroborated the previously delimited species despite high levels of intraspecific variability that overlapped with interspecific variation in many instances. Morphological species delimitation was generally supported by principal component and canonical variate analyses. Characters best suited for morphological species identification were the numbers of growth lines on the carapace, the number of telsonic spines and the number of setae on the furca.