Eocene–Oligocene sea‐level fall drove amphipod habitat shift from marine to freshwater in the Far East

Abstract

The Eocene–Oligocene sea‐level fall has been viewed as a primary driver of biological succession. We used Anisogammaridae living in both marine and freshwater habitats to test the hypothesis that Eocene–Oligocene sea‐level fall can explain the marine–freshwater habitat shift in the Far East. We obtained three mitochondrial and two nuclear fragments for 138 samples representing 31 species, covering marine and freshwater habitats from latitudes 24 to 50°N. The phylogenetic analyses revealed that freshwater Anisogammaridae is monophyletic. Divergence‐time estimation and ancestral range reconstruction indicate that the family originated from a marine habitat in the North Pacific region during the Eocene and separated between marine and freshwater lineages at 38 Ma. The freshwater lineage diversified at 27 Ma, and further diverged into lotic and lentic clades. Our results suggest that the Eocene–Oligocene sea‐level fall provided an opportunity for marine‐derived Anisogammaridae to shift to new freshwater habitats. The freshwater anisogammarids dispersed from north to south, resulting in the restriction of current marine species restricted to the latitudes 35–50°N and the range of freshwater species in latitudes 24–40°N. Deep divergences within the freshwater lineage were related to the separation of lotic and lentic environments and the opening of the Japan Sea.

Ancient volcanos as species pumps: A case study of freshwater amphipods in Northeast Asia

“…The separation between the CI‐1 and CI‐2 subclades occurred at ~19.56 Ma, synchronous with the opening of the Sea of Japan during the 21–14 Ma (Zhang et al, 2018). Similar diversification patterns were found in Anisogammaridae amphipods (Li et al, 2020), spiders (Ballarin & Li, 2018) and fishflies (Jiang et al, 2020).…”

“…The majority of the G. nekkensis species complex has a restricted distribution, suggesting vicariance events associated with initial volcanism may have caused the diversification. The separation between the CI-1 and CI-2 subclades occurred at ~19.56 Ma, synchronous with the opening of the Sea of Japan during the 21-14 Ma(Zhang et al, 2018).Similar diversification patterns were found in Anisogammaridae amphipods(Li et al, 2020), spiders(Ballarin & Li, 2018) and fishflies(Jiang et al, 2020).The western clade II diversified around the western and central Changbai Mts and expanded westward to the Taihang Mts at ~20.43 Ma (Figures2 and 3). The diversification of subclade CII-1a (15.14 Ma) was probably driven by the second volcanic eruption along the central fault of the Changbai in the mid-Miocene.…”

“…This program can make probabilistic inference of ancestral ranges and quantify comparisons of historical distribution scenarios under different models. We defined five geographical areas according to climate, geographic divisions, phylogeny and the current distribution of G. nekkensis species complex (He et al, 2018; Li et al, 2020; Yang et al, 2017): Taihang Mts (A), Changbai Mts (B), Russian Far East (C), Korea (D), and Japan (E). The maximum number of occupied areas for each ancestral node was set as two.…”

A New Species of the Genus Pseudocrangonyx (Crustacea: Amphipoda: Pseudocrangonyctidae) from Yonaguni Island, Southwestern Japan, and Historical Biogeographic Insights of Pseudocrangonyctids

“…The opening of the Sea of Japan is involved in the diversification of freshwater animals between the continent and the Japanese Archipelago (Sasaki et al, 2007;Tominaga et al, 2016;Li et al, 2020). Geohistorical studies have shown that the Japanese archipelago, once part of the Asian continent, was separated from the continent by the opening of the Sea of Japan, which is divided into two stages: the beginning of the opening (ca.…”

On the brink of extinction: a new freshwater amphipod Jesogammarus acalceolus (Anisogammaridae) from Japan

“…The former is distinguished from the latter mainly by having an antennal sensory organ termed the calceolus ( Morino 1985 ; Bousfield and Morino 1992 ). However, though molecular phylogenetic studies have been conducted previously on Anisogammaridae , the phylogenetic relationship between Jesogammarus and Ramellogammarus has not yet been fully clarified (Macdonald III 2005; Tomikawa et al 2010 ; Li et al 2020 ).…”