Cladocerans and copepods are globally important freshwater zooplankton groups, differing in reproductive modes and dispersal abilities. We compared genetic variation of two common taxa of these crustaceans, the Daphnia longispina species complex (known to harbour multiple cryptic lineages) and Eucyclops serrulatus (morphologically and ecologically variable morphospecies), in lakes of ten Eastern European mountain ranges. We expected to discover cryptic lineages in both groups, and to observe different geographical patterns of diversity because of differences in life cycles. Within E. serrulatus, limited sampling through lowland habitats indeed showed the presence of eight highly divergent clades, probably cryptic species, but most of these were not found in the studied mountain lakes. Such a pattern was congruent with the diversity of the D. longispina complex. Regional coexistence of multiple clades within respective species complexes (two in Eucyclops and three in Daphnia) was observed only in the Tatra Mountains (on the Polish-Slovak border). In all other studied mountain ranges (in the Balkans), only single lineages of Daphnia and Eucyclops, respectively, were present, showing similar intraspecific patterns and no evidence for stronger dispersal limitation in Eucyclops than in Daphnia. Our results indicate that substantial cryptic variation may be expected in seemingly widespread copepod taxa. However, detection of cryptic lineages is not a general pattern in mountain lakes, although these habitats harbour substantial genetic diversity in crustacean zooplankton.
Kraj ı cek, M., Fott, J., Miracle, M.R., Ventura, M., Sommaruga, R., Kirschner, P., Cern y, M. (2015). The genus Cyclops (Copepoda, Cyclopoida) in Europe. -Zoologica Scripta, 45, 671-682. Although copepods of the genus Cyclops are among the most common and dominant plankton taxa of lakes in the northern temperate zone, their taxonomy is still unclear. We analysed an extensive array of Cyclops populations from Europe by means of molecular methods and evaluated morphological characters. Altogether, 68 populations of Cyclops species were sampled, assigned to morphospecies and sequenced for the 12S rRNA gene. Selected populations of each morphospecies were additionally sequenced for three mitochondrial (16S rRNA, cytochrome b, COI) and two nuclear genes (18S rRNA, ITS1) and analysed for micromorphological traits. Our analysis revealed fifteen lineages that can be regarded as separate species. Thirteen of these match currently accepted species, while the remaining two lineages were distinct from the other described species. Thus, their taxonomic status is open to further studies. Besides taxonomy, our study gives new insights into the ecology, distribution and phylogenetic relationships of these species. Finally, a set of morphological traits was selected to facilitate identification.
-Invasive species are a global problem, which costs the world economy billions of dollars and world ecosystems millions of tons of herbicides, pesticides and other cides. Anthropogenic translocation of freshwater copepods associated with early shipping activities was postulated for some time, but was never tested with molecular tools. Here, we examine global molecular diversity of one cyclopoid species, test if the current cosmopolitan distribution is a result of anthropogenic translocation or natural dispersal, and investigate a possibility of cryptic speciation. We use patterns of haplotype frequency of DNA and RNA sequences of four genes (12S, 16S, 18S and cytB) and 11 populations (from England, Scotland, France, Germany, USA, New Zealand and Australia) to test inter-and intrapopulation variability, and three different methods (neighbour joining (NJ), maximum likelihood (ML) and maximum parsimony (MP)) for reconstructing their phylogenetic relationships. They were then tested against two competing hypotheses, and complemented by comparative morphology of microcharacters. Reconstructed phylogenies present strong evidence for anthropogenic translocation, with the same haplotype found in highly disjunct populations in Western Australia, Germany and the USA. Four different clades were revealed with the 12S, 16S and cytB genes, probably representing four cryptic species. Morphological examination of females of two clades contributed a set of microcharacters that can be used in the future taxonomic revision of this species complex. We prove for the first time that cuticular pores and sensilla are homologous structures. This research provides evidence for both homogenization of world freshwater fauna and our inadequate methods of identifying some of its most common species.
Size differentiation has been considered an important phenomenon in evolution, and in situ speciation was hypothesized in the past for the parapatríc subterranean Western Australian Diacyclops Kiefer, 1927 species from the a///co/<2-group, based on morphological evidence. Aims of this study are to: derive their prehminary molecular phytogenies based on mitochondríal (12S) and nuclear (18S) genes; test if morpho-species are supported by molecular data; examine monophyly of the a/ii'co/a-group; and test whether the size differences evolved in situ after colonization by a single ancestral species or resulted from different phytogeny. Analyses of the 12S sequences reveal at least six well defined clades, each corresponding to one morpho-species. The divergences are very high between all species, suggesting only a remote relationship, with those between sympatríc species with significant size difference being in excess of 27%. Surprísingly, all analyses show very high bootstrap values for the clade formed by two cosmopolitan surface-water species, Diacyclops bisetosus (Rehberg, 1880) and D. bicuspidatus (Claus, 1857), despite numerous morphological differences. The 18S dataset also supports only a remote relationship between Diacyclops scanloni Karanovic, 2006 and two other Westem Australian members of the alticola-group: D. humphreysi s. str. Pesce &De Laurentiis, 1996 and D. sobeprolatus Karanovic, 2006. Preliminary analyses suggest absence of in situ speciation and parallel evolution in the Westem Austrahan Diacyclops, interspecific size differentiation being a result of different phytogeny. The alticola-groüp may be polyphyletic, and we recognize morphological characters that define two main lineages. A possibility of cryptic speciation in the cosmopolitan D. bisetosus is also suggested, and several sequences of Diacyclops available from GenBank are recognized either as contamination or misidentification. "RÉSUMÉ La différenciation par la taille a été considérée comme un phénomène important dans l'évolution, et l'hypothèse de la spéciation in situ a été proposée dans le passé pour les espèces souterraines parapatriques du genre Diacyclops Kiefer, 1927 appartenant au groupe alticola, à partir des données morphologiques. Les objectifs de cette étude sont : élaborer leur phylogénie moléculaire préhminaire à partir de gènes mitochondriaux (12S) et nucléaires (18S) ; tester si les espèces morphologiques sont soutenues par les données moléculaires ; examiner la monophyhe du groupe alticola ; et enfin tester si les différences de taille ont évolué in situ après colonisation par une seule espèce ancestrale ou si elles résultent d'une phylogénie différente. Les analyses des séquences de 12S révèlent au moins six clades bien définis, correspondant chacun à une espèce morphologique. Les divergences sont très élevées entre toutes les espèces, suggérant seulement une relation très éloignée, avec celles parmi les espèces sympatriques ayant une différence de taille significative de plus de 27%. De façon surprenante, toutes les a...
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