The female cloaca of an oviparous caecilian amphibian (Gymnophiona): functional and seasonal aspects

Authors

  • Susanne Kuehnel,

    1. Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum, Friedrich-Schiller-Universität Jena, Erbertstrasse 1, 07743 Jena, Germany
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  • Julia Herzen,

    1. Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Str. 1, 21502 Geesthacht, Germany
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  • Thomas Kleinteich,

    1. Biozentrum Grindel und Zoologisches Museum Universität Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany
    2. Friday Harbor Laboratories, University of Washington, 620 University Road, Friday Harbor, WA, 98250, USA
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  • Felix Beckmann,

    1. Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Str. 1, 21502 Geesthacht, Germany
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  • Alexander Kupfer

    1. Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum, Friedrich-Schiller-Universität Jena, Erbertstrasse 1, 07743 Jena, Germany
    2. Department of Biology and Didactics, Section Integrative Zoology and Biodiversity, University of Siegen, Adolf-Reichwein Str. 2, 57068 Siegen, Germany
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Susanne Kuehnel, Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum, Friedrich-Schiller-Universität Jena, Erbertstrasse 1, 07743 Jena, Germany. E-mail: susanne.kuehnel@uni-jena.de

Abstract

Kuehnel, S., Herzen, J., Kleinteich, T., Beckmann, F. and Kupfer, A. 2011. The female cloaca of an oviparous caecilian amphibian (Gymnophiona): functional and seasonal aspects. —Acta Zoologica (Stockholm) 00:1–14.

Reproductive morphology is receiving increased attention in animals that have variable reproductive modes combined with internal fertilization. Exceptionally among amphibians all caecilian species practice internal fertilization via an intromittent organ: an everted part of the male cloaca (phallodeum or phallus). Because research has mostly concentrated on males, knowledge of the female cloacal morphology is scarce. Here, we present the first single-species study of the functional morphology of the female cloaca of an oviparous, phylogenetically basal caecilian (Ichthyophis cf. kohtaoensis). We have analyzed female cloacal shape during the reproductive cycle combining conventional histology with 3D-reconstruction. All females are similar in their overall cloacal structure with some differences in size and histology associated with the reproductive cycle. The female cloaca is divided into two distinct chambers similar to the male condition. The cranial chamber contains urogenital pockets into which oviducts and Wolffian ducts open and which may have function during oviposition. The caudal cloacal chamber bears a novel feature – dorsolateral blind sacs, which are homologous to the male condition, but are considerably smaller. The study of female cloacal morphology is essential to understanding the evolution of the caecilian reproductive system and contributes to the understanding of tetrapod genital morphology in general.

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