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Nickel J.M.,Biozentrum Grindel and Zoologisches Museum | Brandt A.,Biozentrum Grindel and Zoologisches Museum
Zootaxa | Year: 2013

A new antarcturid species, Fissarcturus dorotheae sp. nov., from the Southern Ocean is described. During the ANDEEP II expedition in March 2002, specimens of the new species were collected aboard the RV Polarstern off the South Sand-wich Islands. The new species is most similar to Fissarcturus sandwichi Brandt, 2007, but can be easily distinguished from it by the absence of the cauliflower-like spination, the number of articles of the antennal flagellum as well as the coxal spination. It also can be differentiated from F. sandwichi by the spinulation of the supraocular spines, the tubercular-like spination of the cephalothorax and the absence of tubercles and denticulate spines on the pereopods. The new species dif-fers from all other species of the genus by the strong spinulated frontally bent supraocular spines and the weakly pro-nounced dorsal spination. A distribution map of all known Fissarcturus species is provided. Copyright © 2013 Magnolia Press.

Rehm P.,Biozentrum Grindel and Zoologisches Museum | Borner J.,Biozentrum Grindel and Zoologisches Museum | Meusemann K.,Zoologisches Forschungsmuseum Alexander Koenig | von Reumont B.M.,Zoologisches Forschungsmuseum Alexander Koenig | And 4 more authors.
Molecular Phylogenetics and Evolution | Year: 2011

Molecular sequences do not only allow the reconstruction of phylogenetic relationships among species, but also provide information on the approximate divergence times. Whereas the fossil record dates the origin of most multicellular animal phyla during the Cambrian explosion less than 540. million. years. ago. (mya), molecular clock calculations usually suggest much older dates. Here we used a large multiple sequence alignment derived from Expressed Sequence Tags and genomes comprising 129. genes (37,476 amino acid positions) and 117. taxa, including 101. arthropods. We obtained consistent divergence time estimates applying relaxed Bayesian clock models with different priors and multiple calibration points. While the influence of substitution rates, missing data, and model priors were negligible, the clock model had significant effect. A log-normal autocorrelated model was selected on basis of cross-validation. We calculated that arthropods emerged ~600. mya. Onychophorans (velvet worms) and euarthropods split ~590. mya, Pancrustacea and Myriochelata ~560. mya, Myriapoda and Chelicerata ~555. mya, and 'Crustacea' and Hexapoda ~510. mya. Endopterygote insects appeared ~390. mya. These dates are considerably younger than most previous molecular clock estimates and in better agreement with the fossil record. Nevertheless, a Precambrian origin of arthropods and other metazoan phyla is still supported. Our results also demonstrate the applicability of large datasets of random nuclear sequences for approximating the timing of multicellular animal evolution. © 2011 Elsevier Inc.

Descriptions of Macrostylis antennamagna sp. n. and M. uniformis sp. n. are presented with notes on intraspecific variability and sexual dimorphism. M. uniformis sp. n. showes differences to M. antennamagna sp. n. in the length of the antenna 2, the shape of the pleotelson and length of uropods. The genus Desmostylis Brandt, 1992 (formerly including the two species D. obscurus Brandt, 1992 and D. gerdesi Brandt, 2002) is synonymised with the genus Macrostylis. Based on type material additional remarks and additions to the original descriptions are provided for both species. Results lead to following nomenclatorial changes: M. obscurus (Brandt, 1992), comb. n. and M. gerdesi (Brandt, 2002), comb. n. A setal nomenclature is proposed and the diagnosis for the family is revised. © T. Riehl, A. Brandt.

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