The noncosmopolitanism paradigm of freshwater zooplankton: insights from the global phylogeography of the predatory cladoceran Polyphemus pediculus (Linnaeus, 1761) (Crustacea, Onychopoda)

Abstract

A major question in our understanding of eukaryotic biodiversity is whether small bodied taxa have cosmopolitan distributions or consist of geographically localized cryptic taxa. Here, we explore the global phylogeography of the freshwater cladoceran Polyphemus pediculus (Linnaeus, 1761) (Crustacea, Onychopoda) using two mitochondrial genes, cytochrome c oxidase subunit I and 16s ribosomal RNA, and one nuclear marker, 18s ribosomal RNA. The results of neighbour-joining and Bayesian phylogenetic analyses reveal an exceptionally pronounced genetic structure at both inter- and intra-continental scales. The presence of well-supported, deeply divergent phylogroups across the Holarctic suggests that P. pediculus represents an assemblage of at least nine, largely allopatric cryptic species. Interestingly, all phylogenetic analyses support the reciprocal paraphyly of Nearctic and Palaearctic clades. Bayesian inference of ancestral distributions suggests that P. pediculus originated in North America or East Asia and that European lineages of Polyphemus were established by subsequent intercontinental dispersal events from North America. Japan and the Russian Far East harbour exceptionally high levels of genetic diversity at both regional and local scales. In contrast, little genetic subdivision is apparent across the formerly glaciated regions of Europe and North America, areas that historical demographic analyses suggest that were recolonized just 5500-24 000 years ago.

How do freshwater organisms cross the “dry ocean”? A review on passive dispersal and colonization processes with a special focus on temporary ponds

“…Nowadays, a large consensus is achieved on the fact that the cosmopolitanism paradigm has to give way to the evidences of pronounced ''regionalism'' or ''provincialism'' which emerged in almost all the investigated taxa (e.g. De Gelas & De Meester, 2005;Xu et al, 2009;Crease et al, 2012). At a within-species level, quite a low ongoing gene flow between conspecific populations is usually observed (Boileau et al, 1992), which contributes to the presence of marked phylogeographic structures in the vast majority of inland water taxa (e.g.…”

Molecular study of worldwide distribution and diversity of soil animals

“…However, it has been demonstrated by others (2,3) that in general, unicellular eukaryote organisms such as protists and diatoms disperse over shorter geographical distances than larger multicellular organisms such as annelids, nematodes, and bivalves in both marine and terrestrial environments. A global molecular study of freshwater cladocerans found that continental and regional endemism is common and cosmopolitan species are rare (4). It was found that taxa described in the morphological literature as cosmopolitan are not homogeneous at the molecular level, suggesting that taxa previously identified as cosmopolitan can be an artifact resulting from inaccurate taxonomy, the presence of morphological stasis, or phenotype plasticity.…”

Pleistocene‐driven diversification in freshwater zooplankton: Genetic patterns of refugial isolation and postglacial recolonization in Leptodora kindtii (Crustacea, Cladocera)

“…In the Nearctic, the Pacific coast (e.g., Cascadia) and the Bering land bridge that joined present-day Alaska and eastern Siberia are well-known glacial refugia for a number of freshwater cladoceran species complexes, including Sida crystallina (Cox and Hebert 2001), Daphnia pulex (Weider and Hobaek 2003), Daphnia longispina (Ishida and Taylor 2007a), Daphnia galeata (Ishida and Taylor 2007b), Holopedium gibberum , and Polyphemus pediculus (Xu et al 2009). In addition, phylogenetic investigations have uncovered high levels of genetic diversity and endemism along the Pacific and Atlantic coasts of Canada (e.g., Queen Charlotte Islands and Nova Scotia) and in the Great Lakes and Mississippi regions (Hebert et al 2003;Dooh et al 2006), indicating the presence of glacial refugia in these areas.…”

“…A classical southern refuge (e.g., Iberian Peninsula) was likely important for the rotifer Brachionus manjavaca (Gomez et al 2007). However, for the isopod Asellus aquaticus and the cladoceran P. pediculus, it has been suggested that the Pannonian basin of central Europe (Verovnik et al 2005) and the region north of the Ponto-Caspian basin (Xu et al 2009) harbored refugial populations that subsequently recolonized large parts of the west Palearctic. Moreover, four moderately divergent and geographically distinct lineages of Daphnia magna were identified in Europe.…”