Terrestrial invasion of pomatiopsid gastropods in the heavy-snow region of the Japanese Archipelago

Abstract

BackgroundGastropod mollusks are one of the most successful animals that have diversified in the fully terrestrial habitat. They have evolved terrestrial taxa in more than nine lineages, most of which originated during the Paleozoic or Mesozoic. The rissooidean gastropod family Pomatiopsidae is one of the few groups that have evolved fully terrestrial taxa during the late Cenozoic. The pomatiopsine diversity is particularly high in the Japanese Archipelago and the terrestrial taxa occur only in this region. In this study, we conducted thorough samplings of Japanese pomatiopsid species and performed molecular phylogenetic analyses to explore the patterns of diversification and terrestrial invasion.ResultsMolecular phylogenetic analyses revealed that Japanese Pomatiopsinae derived from multiple colonization of the Eurasian Continent and that subsequent habitat shifts from aquatic to terrestrial life occurred at least twice within two Japanese endemic lineages. Each lineage comprises amphibious and terrestrial species, both of which are confined to the mountains in heavy-snow regions facing the Japan Sea. The estimated divergence time suggested that diversification of these terrestrial lineages started in the Late Miocene, when active orogenesis of the Japanese landmass and establishment of snowy conditions began.ConclusionsThe terrestrial invasion of Japanese Pomatiopsinae occurred at least twice beside the mountain streamlets of heavy-snow regions, which is considered the first case of this event in the area. Because snow coverage maintains stable temperatures and high humidity on the ground surface, heavy-snow conditions may have paved the way for these organisms from freshwater to land via mountain streamlets by preventing winter desiccation in mountain valleys. The fact that the terrestrialization of Pomatiopsidae occurred only in year-round wet environments, but not in seasonally dried regions, provides new insight into ancient molluscan terrestrialization.

Modelled ocean changes at the Plio-Pleistocene transition driven by Antarctic ice advance

“…Our model simulations do show a reduction of the temperature difference between the North Atlantic and North Pacific from the Pliocene to the pre-industrial (Table 2). However, the simulated difference in the Pliocene is not as enhanced as seen in the records2, perhaps suggesting that there could be local palaeogeographic changes not incorporated into the PlioMIP experimental design that affect the temperatures on Shatsky Rise20212223. As North Pacific circulation similar to modern is produced in the Pliocene simulations with more ice, this causes a warming of North Pacific waters, explaining the long-term increases in North Pacific temperatures during the initiation of Northern Hemisphere Glaciation2.…”

Egg perivitelline fluid proteome of a freshwater snail: Insight into the transition from aquatic to terrestrial egg deposition

“…Overall, the results of this study will facilitate further research on the evolution of PVF proteins during the transition from underwater to terrestrial egg deposition in Ampullariidae, in particular the Old World lineage (e.g., the underwater ovipositor Lanistes and terrestrial ovipositor Pila ). The data can also be used in comparative genomic studies aiming to understand the mechanisms of terrestralization in Gastropoda …”

Molecular phylogeny, biogeography and ecological niche modelling ofCardiocrinum(Liliaceae): insights into the evolutionary history of endemic genera distributed across the Sino-Japanese floristic region

“…The C. cathayanum lineage probably migrated into south Japan during the Pliocene (approx. 4Á97 Mya), a period corresponding to the orogenesis of the Japanese Archipelago and regression of the East China Sea, with the main islands of south Japan constituting the eastern margin of the Asian continent (Iijima and Tada, 1990;Kameda and Kato, 2011). Thereafter, expansion of the East China Sea promoted range fragmentation, vicariance and isolation for the populations in Japan, which provided opportunities for allopatric (incipient) speciation of C. cordatum to occur through the action of selection and/or genetic drift.…”