Historical dispersal and host-switching formed the evolutionary history of a globally distributed multi-host parasite - The Ligula intestinalis species complex.

Studies on parasite biogeography and host spectrum provide insights into the processes driving parasite diversification. Global geographical distribution and a multi-host spectrum make the tapeworm Ligula intestinalis a promising model for studying both the vicariant and ecological modes of speciation in parasites. To understand the relative importance of host association and biogeography in the evolutionary history of this tapeworm, we analysed mtDNA and reduced-represented genomic SNP data for a total of 139 specimens collected from 18 fish-host genera across a distribution range representing 21 countries. Our results strongly supported the existence of at least 10 evolutionary lineages and estimated the deepest divergence at approximately 4.99-5.05 Mya, which is much younger than the diversification of the fish host genera and orders. Historical biogeography analyses revealed that the ancestor of the parasite diversified following multiple vicariance events and was widespread throughout the Palearctic, Afrotropical, and Nearctic between the late Miocene and early Pliocene. Cyprinoids were inferred as the ancestral hosts for the parasite. Later, from the late Pliocene to Pleistocene, new lineages emerged following a series of biogeographic dispersal and host-switching events. Although only a few of the current Ligula lineages show narrow host-specificity (to a single host genus), almost no host genera, even those that live in sympatry, overlapped between different Ligula lineages. Our analyses uncovered the impact of historical distribution shifts on host switching and the evolution of host specificity without parallel host-parasite co-speciation. Historical biogeography reconstructions also found that the parasite colonized several areas (Afrotropical and Australasian) much earlier than was suggested by only recent faunistic data.

Integrating phylogenetic, phylogeographic, and morphometric analyses to reveal cryptic lineages within the genus Asaccus (Reptilia: Squamata: Phyllodactylidae) in Iran.

The Middle Eastern endemic genus Asaccus comprises Southwest Asian leaf-toed geckos. To date, this genus includes 19 species of leaf-toed geckos (seven in Arabia and 12 in the Zagros Mountains). Despite a recent study on the taxonomy and phylogeny of Asaccus species in Iran, controversies still remain surrounding the phylogeny and phylogeography of the genus. Here, we used an integrative approach to determine the phylogeny and phylogeography of Asaccus species using two mitochondrial genes (12 S and Cyt b), and one nuclear gene (c-mos). Our results uncovered 22 distinct lineages, demonstrating a significant cryptic diversity that challenges the current morphological classifications of these species. Phylogenetic analyses reinforce the monophyly of the Asaccus group, positioning A. montanus as a basal lineage, which supports a deep evolutionary divergence dating back to the Late Oligocene, approximately 27.94 million years ago. This genetic diversity also highlights the impact of historical climatic and geographical changes on species diversification. The findings advocate for an integrative approach combining both molecular and morphological data to resolve species identities accurately, thereby enhancing conservation strategies to protect these genetically distinct lineages.

The phylogeny, phylogeography, and diversification history of the westernmost Asian cobra (Serpentes: Elapidae: Naja oxiana) in the Trans-Caspian region.

We conducted a comprehensive analysis of the phylogenetic, phylogeographic, and demographic relationships of Caspian cobra (Naja oxiana; Eichwald, 1831) populations based on a concatenated dataset of two mtDNA genes (cyt b and ND4) across the species' range in Iran, Afghanistan, and Turkmenistan, along with other members of Asian cobras (i.e., subgenus Naja Laurenti, 1768). Our results robustly supported that the Asiatic Naja are monophyletic, as previously suggested by other studies. Furthermore, N. kaouthia and N. sagittifera were recovered as sister taxa to each other, and in turn sister clades to N. oxiana. Our results also highlighted the existence of a single major evolutionary lineage for populations of N. oxiana in the Trans-Caspian region, suggesting a rapid expansion of this cobra from eastern to western Asia, coupled with a rapid range expansion from east of Iran toward the northeast. However, across the Iranian range of N. oxiana, subdivision of populations was not supported, and thus, a single evolutionary significant unit is proposed for inclusion in future conservation plans in this region.

Evolutionary history and postglacial colonization of an Asian pit viper (Gloydius halys caucasicus) into Transcaucasia revealed by phylogenetic and phylogeographic analyses.

It has been generally acknowledged that glacial climates at the time of the Pleistocene altered the patterns of species distributions, prompting latitudinal and altitudinal distribution shifts in several species, including poikilothermic species commonly known for their thermal sensitivity. However, the historical phylogeographic patterns of such species have remained largely unknown. Here, we present the historical biogeographic, phylogenetic, and phylogeographic relationships of the Caucasian pit viper, G. h. caucasicus, based on two mtDNA (cyt b and ND4) and one nDNA (c-mos) genes. This pit viper represents the westernmost member of the Crotalinae subfamily in the Palearctic and occurs in a variety of habitats, from 30 m to 3,000 m above sea level. In Iran, it is distributed on the northern and southern slopes of the Alborz Mountains, rendering it a target for phylogenetic and phylogeographic studies of a terrestrial poikilothermic animal. Our study identified four Iranian lineages of G. h. caucasicus along the northeastern to northwestern slopes of the Alborz Mountains and southern Azerbaijan (Talysh Mountains). Diversification of the Iranian lineages highlights population expansion and subsequent isolation into four plausible refugial areas during the Quaternary paleo-climatic oscillations, confirmed by our molecular dating and historical biogeographic analyses. The results of coalescence-based simulations support the incursion of the species from northeastern Iran to the western end of the Alborz, and then toward Transcaucasia via two directions: northern and southern slopes of the Alborz Mountains. Furthermore, our results clearly implied that G. h. caucasicus should be elevated to species rank and further referred to as G. caucasicus (Nikolsky, 1916).