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  • Huvudmeny

Patterns of morphological character evolution: an annelid perspective

TEM-fotografi av annelider. Foto: Lena Gustavsson

Annelid photographed i TEM (Transmission Electron Microscope). Photo: Lena Gustavsson

Summary

The main focus of my project is to learn more about morphological character evolution in a phylogenetic context.

One of the goals is to erect homology hypotheses of morphological characters. The morphological characters are then used as a data base for reconstructing of a hypothesis of phylogenetic relationships (=tree) in combination with existing DNA sequences or are mapped on existing trees to study the character evolution.

The emphasis of my research is to unravel annelid character evolution.

Several anatomical structures are studied: body wall muscles, epidermis and cuticle, and genital ducts, using different methods such as transmission electron microscopy (TEM) and routin histology.

Another goal of the project is to study the morphology of homologous characters; characters that come out as derived from a common ancestor in both DNA and morphological analyses and that have long been recognized by morphologists to unite a certain group of organisms, e.g. the clitellum of Clitellata and the chaetae of Annelida. How similar or dissimilar are homologous morphological characters? This will have an impact on how we can find and interpret morphological characters from fossils and how they can be used as a tool in order to shed light on the phylogeny of the Metazoa. Today we find fossils we cannot even make a good guess to what clade they belong since we know too little about morphology in general.

Projekt Participants at NRM

Lena Gustavsson (principal investigator)

Carina Svensson (laboratory assistant, TEM)

Anna Persson (senior assistant)

External Projekt Participants

Christer Erséus (researcher) Göteborg University

Selected Publications

De Wit, P., Erséus, C. & Gustavsson, L. 2011. Ultrastructure of the body wall of three species of Grania (Annelida: Clitellata: Enchytraeidae). Acta Zoologica, 92: 1-11.

Envall, I., Gustavsson, L.M., Erséus, C. 2012. Genetic and chaetal variation in Nais worms (Annelida, Clitellata, Naididae). Zoological Journal of Linnean Society 165 (3): 495-520.

Marotta, R., Ferraguti, M., Erséus, C. & Gustavsson, L. 2008. Combined data phylogenetics and character evolution of Clitellata (Annelida) using 18S rDNA and morphology. Zoological Journal of Linnean Society, 154: 1-26.