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Systematics of the family Aspidoderidae Skrjabin and Schikhobalova, 1947 (Heterakoidea) parasites of neotropical mammals

F. Agustin Jimenez-Ruiz, University of Nebraska - Lincoln

Abstract

The phylogenetic relationships among nematodes of the family Aspidoderidae are elucidated using characters derived from both morphology and mitochondrial and nuclear DNA. The resulting trees do not agree with the previous classification proposed for the family because neither the subfamilies Lauroiinae, including Lauroia Proença, 1938, Nematomystes Sutton, Chabaud and Durette-Desset, 1980 Paraspidodera (Rudolphi, 1819), nor Aspidoderinae are natural groupings. Based on this study I propose to include Lauroia as the only genus in Lauroiinae, and the rest of the genera, including Aspidodera Railliet and Henry, 1912, Nematomystes, Paraspidodera, and Proencaia Gomes and Pereira, 1970 in Aspidoderinae. At the generic level the resulting hypothesis also shows that the genera Aspidodera, Paraspidodera , and Nematomystes need an emendation since Nematomystes should include Aspidodera raillieti Travassos, 1914, and Paraspidodera uncinata (Rudolphi, 1819) should be included as a species in Aspidodera. The signal from the mitochondrial ribosomal large subunit (rLSU) was incongruent with the other two data partitions, as suggested by the results of the Length Difference Tests and corroborated by the Tests of Taxonomic Congruence. However, the results from the Tests of Taxonomic Congruence indicated that the signal in rLSU was weaker than the signal from the internal transcriber spacers (ITSs) and morphology. The combination of all three datasets resulted in a topology congruent with the datasets from ITS and morphology. The phylogenetic and coevolutionary relationships between these nematodes and their mammalian hosts were also investigated using my new data on nematodes and published trees for the hosts. These analyses suggest that the group originated and cospeciated with Dasypodidae and an early event of host switching caused the parasites to transfer and infect opossums and subsequently cricetine rodents after the invasion of these mammals into South America from the North. The species of parasites associated with xenarthrans continued speciation until the point in which P. uncinata originated as a result of a later invasion of hystricognath rodents. The hypothesis that the association was shaped by cospeciation was rejected using event based methods, which maximize the cospeciation events over host switching cases, therefore host switching may have caused the pattern of distribution of the extant species of Aspidoderidae. ^

Subject Area

Biology, Zoology

Recommended Citation

Jimenez-Ruiz, F. Agustin, "Systematics of the family Aspidoderidae Skrjabin and Schikhobalova, 1947 (Heterakoidea) parasites of neotropical mammals" (2004). ETD collection for University of Nebraska - Lincoln. AAI3137864.
http://digitalcommons.unl.edu/dissertations/AAI3137864

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