Molecular systematics of the anchovy genus Encrasicholina in the Northwest Pacific

Abstract

The anchovy genus Encrasicholina is an important coastal marine resource of the tropical Indo-West Pacific (IWP) region for which insufficient comparative data are available to evaluate the effects of current exploitation levels on the sustainability of its species and populations. Encrasicholina currently comprises nine valid species that are morphologically very similar. Only three, Encrasicholina punctifer, E. heteroloba, and E. pseudoheteroloba, occur in the Northwest Pacific subregion of the northeastern part of the IWP region. These species are otherwise broadly distributed and abundant in the IWP region, making them the most important anchovy species for local fisheries. In this study, we reconstructed the phylogeny of these three species of Encrasicholina within the Engraulidae. We sequenced 10 complete mitochondrial genomes (using high-throughput and Sanger DNA sequencing technologies) and compared those sequences to 21 previously published mitochondrial genomes from various engraulid taxa. The phylogenetic results showed that the genus Encrasicholina is monophyletic, and it is the sister group to the more-diverse "New World anchovy" clade. The mitogenome-based dating results indicated that the crown group Encrasicholina originated about 33.7 million years ago (nearby the limit Eocene/Oligocene), and each species of Encrasicholina has been reproductively isolated from the others for more than 20 million years, despite their morphological similarities. In contrast, preliminary population genetic analyses across the Northwest Pacific region using four mitogenomic sequences revealed very low levels of genetic differentiation within Encrasicholina punctifer. These molecular results combined with recent taxonomic revisions are important for designing further studies on the population structure and phylogeography of these anchovies.

Systematics of Clupeiformes and testing for ecological limits on species richness in a trans-marine/freshwater clade

“…Divergence times. Our separate mtDNA-and nDNA--based estimates of divergence times suggest that conflicting results reported by previous mtDNA (Lavoué et al, 2013(Lavoué et al, , 2017b and mtDNA+nDNA (Bloom, Lovejoy, 2014) studies on clupeiform divergence times are partially due to the different genes in these datasets. We estimated divergence times for major clupeiform clades that were nearly always youn- Fig.…”

“…Age estimates for the MRCA of Pristigasteridae and Clupeidae were particularly different between the mtDNA and nDNA datasets. Differences between in our age estimates from previous studies are likely also due to the exclusion of fossils used in previous studies because of uncertainty regarding their placement (Lavoué et al, 2017b): †Gasteroclupea branisai, previously used to set a minimum age for the MRCA of Pristigasteridae, †Nolfia riachuelensis, previously used to set a minimum age for the MRCA of Clupeidae (Bloom, Lovejoy, 2014), and †Lecceclupea ehiravaensis to set a minimum age for the MRCA of the clupeid lineage Ehiravini (Gilchristella + Clupeichthys; Lavoué et al, 2013).…”

“…To time-calibrate our phylogeny we used six exponential calibration priors based upon priors previously used in clupeiform systematics (Bloom, Lovejoy, 2014;Lavoué et al, 2017b):…”

The gut microbiota and colorectal surgery outcomes: facts or hype? A narrative review

“…The authors stressed the probable role of bacterial leakage or translocation through the sutures to justify these results, supported by the well-known appearance of most adhesions in the area of bowel anastomosis [80] . Moreover, recent studies have consistently demonstrated that serotonin production is lower in GF mice and that it is probably mediated by SCFA production [81 , 82] .…”

Multiple freshwater invasions of the tapertail anchovy (Clupeiformes: Engraulidae) of the Yangtze River

“…The 13 samples collected from Chongming, Luchao, and Jingjiang were considered as the anadromous population (SH, n = 13), whereas the other samples were treated as the resident populations. Five samples of C. mystus collected from the Yangtze River were used as outgroups, since it was found closely related to Coilia nasus species complex (Lavoué et al, ). Most samples of the resident populations were collected after October, when the migratory fish had already left freshwater habitat.…”