Delimitation of species is often complicated by discordance of morphological and genetic data. This may be caused by the existence of cryptic or polymorphic species. The latter case is particularly true for certain snail species showing an exceptionally high intraspecific genetic diversity. The present investigation deals with the Trochulus hispidus complex, which has a complicated taxonomy. Our analyses of the COI sequence revealed that individuals showing a T.hispidus phenotype are distributed in nine highly differentiated mitochondrial clades (showing p-distances up to 19%). The results of a parallel morphometric investigation did not reveal any differentiation between these clades, although the overall variability is quite high. The phylogenetic analyses based on 12S, 16S and COI sequences show that the T.hispidus complex is paraphyletic with respect to several other morphologically well-defined Trochulus species (T.clandestinus, T.villosus, T.villosulus and T.striolatus) which form well-supported monophyletic groups. The nc marker sequence (5.8S-ITS2-28S) shows only a clear separation of T.o.oreinos and T.o.scheerpeltzi, and a weakly supported separation of T.clandestinus, whereas all other species and the clades of the T.hispidus complex appear within one homogeneous group. The paraphyly of the T.hispidus complex reflects its complicated history, which was probably driven by geographic isolation in different glacial refugia and budding speciation. At our present state of knowledge, it cannot be excluded that several cryptic species are embedded within the T.hispidus complex. However, the lack of morphological differentiation of the T.hispidus mitochondrial clades does not provide any hints in this direction. Thus, we currently do not recommend any taxonomic changes. The results of the current investigation exemplify the limitations of barcoding attempts in highly diverse species such as T.hispidus.
12 November 2013 in Journal of Zoological Systematics and Evolutionary Research
Rock‐dwelling gastropods are usually patchily distributed in limestone habitats, presumably have low active and passive dispersal ability and often represent narrow‐ranged endemic taxa. Their current taxonomy is predominantly shell morphology based, and it remains unknown whether the morphologically differentiated and geographically separated populations represent phylogenetic clades. In this study, we analysed the hyperdiverse, terrestrial door snail genus Montenegrina. Based on the current taxonomy defined by shell morphology, it contains 29 species and 106 subspecies distributed in the Balkan region. The constructed phylogenetic tree using three mitochondrial markers was used to test whether it agrees with the current taxonomy. In this comprehensive tree, about half of the species and subspecies are monophyletic. Some of the paraphylies could be reasonably resolved by taxonomic changes; that is, some subspecies should be reassigned or raised to species level. Other incongruencies probably arose due to introgression even between distant clades. The histone genes turned out to be unsuitable for elucidating the phylogeny of Montenegrina. In the species‐delimitation tests, considerably more molecular operational taxonomic units were delimited than the number of presently described species. The present data indicate that (a) shell morphology‐based taxonomy and taxon recognition can be problematic in such a large and morphologically highly variable genus; (b) the potential error due to incomplete sampling presents a problem in a genus as variable as Montenegrina; (c) multi‐locus analyses should be conducted to arrive at a better basis for species delimitation; and (d) integrative approaches including genetic as well as morphological/anatomical data from a comprehensive geographic sample are necessary.
Phenotypic similarities among cave-dwelling animals displaying troglomorphic characters (e.g. reduced eyes and lack of pigmentation) have induced a long-term discussion about the forces driving convergent evolution. Here we introduce Garra barreimiae Fowler & Steinitz, 1956, as an interesting system to study the evolution of troglomorphic characters. The only hitherto known troglomorphic population of this species lives in Al Hoota Cave (Sultanate of Oman) close to a surface population. As a first approach, we assessed the genetic differentiation between the two morphotypes of G. barreimiae to determine whether gene flow still occurs.
1 January 2010 in Eco.Mont (Journal on Protected Mountain Areas Research)
The journal “eco.mont” – Journal of protected mountain areas research and management – was published for the first time in June 2009. The journal was founded as a joint initiative of the Alpine Network of Protected Areas (ALPARC), the International Scientific Committee on Research in the Alps (ISCAR), the Austrian Academy of Sciences (ÖAW) and the University of Innsbruck. The journal aims to highlight research on and management issues in protected areas in the Alps without excluding other protected mountain areas in Europe or overseas. Its target audiences are scientists from all related disciplines, managers of protected areas and interested individuals including practitioners, visitors, teachers, etc. The journal presents peer-reviewed articles in English by authors who research protected mountain areas and management issues within these areas. It's published twice a year as a collaboration of the Austrian Academy of Sciences Press – responsible for the e-version – and Innsbruck University Press – responsible for the print version.
The Central and Southern European mountain ranges represent important biodiversity hotspots and show high levels of endemism. In the land snail genus Orcula Held, 1837 nine species are distributed in the Alps and a few taxa inhabit the Carpathians, the Dinarids and the Western Black Sea region. In order to elucidate the general patterns of temporal and geographic diversification, mitochondrial and nuclear markers were analyzed in all 13 Orcula species. We particularly aimed to clarify whether the Alpine taxa represent a monophyletic group and if the local species diversity is rather the result of isolation in geographically separated Pleistocene glacial refuges or earlier Tertiary and Quaternary palaeogeographic events. In order to test if patterns of molecular genetic and morphological differentiation were congruent and/or if hybridization had occurred, shell morphometric investigations were performed on the Orcula species endemic to the Alps. The phylogenetic trees resulting from the analyses of both the mitochondrial (COI, 12S and 16S) and the nuclear (H4/H3) data sets revealed three main groups, which correspond to the three subgenera Orcula, Illyriobanatica and Hausdorfia. The reconstruction of the historic geographic ranges suggested that the genus originated in the Dinarides during the Middle Miocene and first colonized the Alps during the Late Miocene, giving rise to the most diverse subgenus Orcula. Within the latter subgenus (including all Alpine endemics) almost all species were differentiated by both molecular genetic markers and by shell morphometrics, except O. gularis and O. pseudodolium. The present study confirms the importance of the Alps as biodiversity hotspot and origin center of land snail diversity. The species diversity in the subgenus Orcula was likely promoted by Miocene to Pliocene palaeogeographic events and the insular distribution of preferred limestone areas. In some cases, speciation events could be linked to the divergence of populations in glacial refuges during the Pleistocene. Sporadic contact between geographically separated and reproductively not yet isolated populations led to intermixture of haplogroups within species and even hybridization and mitochondrial capture between species.