Interactive 3D anatomy and affinities of the Hyalogyrinidae, basal Heterobranchia (Gastropoda) with a rhipidoglossate ra
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ORIGINAL ARTICLE
Interactive 3D anatomy and affinities of the Hyalogyrinidae, basal Heterobranchia (Gastropoda) with a rhipidoglossate radula Gerhard Haszprunar & Erika Speimann & Andreas Hawe & Martin Heß
Received: 25 January 2011 / Accepted: 26 May 2011 / Published online: 19 June 2011 # Gesellschaft für Biologische Systematik 2011
Abstract Whereas Hyalogyrina Marshall, 1988 was originally considered a skeneid vetigastropod, the family Hyalogyrinidae Warén & Bouchet, 1993 has later been classified as basal Heterobranchia despite their rhipidoglossate radula. In order to evaluate this placement and to shed more light on the origin of all higher Gastropoda, we investigated five representatives of all three nominal hyalogyrinid genera by means of semithin serial sectioning and computer-aided 3D reconstruction of the respective anatomy, which we present in an interactive way. In general the morphological features (shell, external morphology, anatomy) fully confirm the placement of Hyalogyrinidae in the Heterobranchia, but in particular the conditions of the genital system vary substantially within the family. The ectobranch gill of Hyalogyrinidae is shared with Valvatidae, Cornirostridae, and Xylodisculidae; consequently all these families are united in Ectobranchia Fischer, 1884. The rhipidoglossate hyalogyrinid radula suggests independent acquisition of taenioglossate radulae in the Caenogastropoda and other Ectobranchia. Therefore, the origin of the Heterobranchia— and thus of all higher gastropods—looks to have taken place
Electronic supplementary material The online version of this article (doi:10.1007/s13127-011-0048-0) contains supplementary material, which is available to authorized users. G. Haszprunar (*) Zoologische Staatssammlung München, Münchhausenstraße 21, 81247 Munich, Germany e-mail: [email protected] G. Haszprunar : E. Speimann : A. Hawe : M. Heß Department Biology I and GeoBio-Center, Ludwig-Maximilians-Universität München, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
already on the rhipidoglossate, i.e. the ‘archaeogastropod’, level of evolution. Ectobranchia are considered the first extant offshoot of the Heterobranchia; implications for the stem species of the latter are outlined. Keywords Gastropoda . Ectobranchia . Hyalogyrinidae . Interactive 3D anatomy . Systematics . Phylogeny . Heterobranchia
Introduction During the last 25 years major progress has been made in our understanding of the origin of the higher gastropods, i.e. the allogastropod, opisthobranch and pulmonate taxa, the latter two of which are commonly united as Euthyneura. Haszprunar (1985a) first proposed the “HeterobranchiaConcept” in considering certain former ‘mesogastropods’ as linking step by step a basal caenogastropod with a primitive euthyneuran level of organization. These (paraphyletic) ‘allogastropods’ (called heterostrophs by some authors) include, among other taxa, Ectobranchia = Valvatoidea, Architectonicidae and Mathildidae, Omalogyridae, and Rissoellidae; together with the euthyneuran groups these
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