Journal article

Publication year: 2001

Pages: 227-234

Journal: Journal of Zoological Systematics and Evolutionary Research

Volume number: 39

Issue number: 4

ISSN: 0947-5745

DOI Link: https://doi.org/10.1046/j.1439-0469.2001.00171.x

Publisher: Wiley

Abstract: 
In molluscs, the shell characters have historically played an important role in discrimination among species. However, because of the paucity, variability and degree of homoplasy of shell characters, their sole use for taxonomic and systematic studies is controversial in many groups. In the present paper the genus Radoman, 1973 is used as a paradigm to test relationships of taxa that were considered to be species, mainly on the basis of the shell size variations, We tested whether the genus consists of several sympatric and polytypic species or a single species with polymorphic populations and whether the reported shell size differences, on which the description of three putative species is mainly based, are intrinsic or extrinsic. A fragment of the mitochondrial cytochrome oxidase I (COI) gene was used as an independent genetic marker. We found very little genetic variability in 40 specimen, from four populations studied. The nucleotide-sequence diversity (pi) within Populations ranges from 0.0017 to 0,0056 and the nucleotide-sequence divergence (D-xy) between populations from 0.0018 to 0.0051. The phylogenetic network is very compact with two 'groups' of haplotypes that are separated by only two nucleotide positions, A plot of pair-wise nucleotide differences against pairwise shell size differences did not reveal any distinct clusters and a Mantel test did not show any significant associations between the two matrices. Based on the very low genetic diversity, the lack of distinct clusters in the phylogenetic network and the lack of concordance between morphological and genetic differentiation it is concluded that only one species is involved. Adriohydrobia gagatinella. The previously reported morphogroups within Adriohydrobia are probably due to a discrete age structure in these population and/or due to the effect of tretmatode-induced gigantism. The observed genetic patterns in Adriohydrobia indicate a rapid population growth from an ancestral population of small evolutionary-effective size, The present study stresses the importance of testing species-level hypotheses based on shell characters using one or more independent markers.

Harvard Citation style: Wilke, T. and Falniowski, A. (2001) The genus Adriohydrobia (Hydrobiidae : Gastropoda): polytypic species or polymorphic populations?, Journal of Zoological Systematics and Evolutionary Research, 39(4), pp. 227-234. https://doi.org/10.1046/j.1439-0469.2001.00171.x

APA Citation style: Wilke, T., & Falniowski, A. (2001). The genus Adriohydrobia (Hydrobiidae : Gastropoda): polytypic species or polymorphic populations?. Journal of Zoological Systematics and Evolutionary Research. 39(4), 227-234. https://doi.org/10.1046/j.1439-0469.2001.00171.x