Evolution, Systematics and Distribution of Desmosomatidae (Isopoda, Peracarida, Crustacea) in the deep sea

• Main Author: Brix, Saskia Bianca
• Other Authors: Brandt, Angelika (Prof. Dr.)
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Staats- und Universitätsbibliothek Hamburg Carl von Ossietzky 2006
• Subjects: Desmosomatidae; Nannoniscidae; Phylogeny; phylogenetic systematics; taxonomy; deep sea; 590 Tiere (Zoologie); 42.94 Meeresbiologie; Systematik; Tiefsee; Phylogenetische Systematik; Phylogenie; Asseln; Evolution; ddc:590; Southern Ocean
• Online Access: http://nbn-resolving.de/urn:nbn:de:gbv:18-30697; https://ediss.sub.uni-hamburg.de/handle/ediss/1505

The present thesis deals with one deep-sea family of Isopoda: Desmosomatidae Sars, 1897. It contains three major topics: 1) taxonomy, 2) biogeographic and distributional aspects (aspects of zoogeography), 3) phylogeny. Based on morphological characters, a revision of the family Desmosomatidae Sars, 1897 is presented. In the taxonomy part, four new species, Desmosoma renatae sp. nov., Eugerdella theodori sp. nov., Momedossa longipedis sp. nov. and Torwolia tinbienae sp. nov. are described from material of the DIVA-1 expedition and Eugerdella serrata sp. nov. is described from material of the ANDEEP-expeditions. Eight new species are described from museum material (Museum Victoria, Melbourne) and eight incompletely described species are redescribed. Furthermore, modified diagnoses are presented for all genera. The genera are discussed. One new genus is erected (Pseudergella gen. nov.). As result of the phylogenetic discussion, Nannoniscidae Hansen, 1916 are included in Desmosomatidae Sars, 1897. Five subfamilies of Desmosomatidae are defined and discussed (phylogeny part): Austroniscinae, Desmosomatinae, Eugerdellatinae, Pseudomesinae and Nannoniscinae. As zoogeographic aspects, the results of the DIVA-1 and the ANDEEP expedions I & II are presented for the family Desmosomatidae sensu Hessler (1970) and Wägele (1989) excluding the genus Thaumastosoma. The percentage of new species in the DIVA-1 samples is very high (93%) and only slightly lower when Nannoniscidae are included in the family (85,7 %). Desmosomatidae are next to Munnopsididae the second most dominant isopod family in the samples. As for all Isopoda, the distribution of Desmosomatidae at the ANDEEP stations is found to be rather patchy and many species are rare. In the ANDEEP samples, Desmosomatidae (48 species) are more divers than in the DIVA-1 samples (27 species). Their abundance in the deep Southern Ocean is lower than in the Angola Basin. The percentage of potential endemites in the DIVA-1 samples is 33,3 %, in the ANDEEP samples 52 %. With ...