High morphological plasticity in populations of brine shrimp subjected to different environmental conditions, mainly salinity, hindered for centuries the identification of the taxonomic entities encompassed within Artemia. In addition, the mismatch between molecular and morphological evolution rates complicates the characterization of evolutionary lineages, generating taxonomic problems. Here, we propose a phylogenetic hypothesis for Artemia based on two new complete mitogenomes, and determine levels of congruence in the definition of evolutionary units using nuclear and mtDNA data. We used a fossil of Artemia to calibrate the molecular clock and discuss divergence times within the genus. The hypothesis proposed herein suggests a more recent time frame for lineage splitting than previously considered. Phylogeographic analyses were performed using GenBank available mitochondrial and nuclear markers. Evidence of gen e flow, identified through discordances between nuclear and mtDNA markers, was used to reconsider the specific status of some taxa. As a result, we consider Artemia to be represented by five evolutionary units: Southern Cone, Mediterranean—South African, New World, Western Asian, and Eastern Asian Lineages. After an exhaustive bibliographical revision, unavailable names for nomenclatural purposes were discarded. The remaining available names have been assigned to their respective evolutionary lineage. The proper names for the evolutionary units in which brine shrimps are structured remain as follows: Artemia persimilis Piccinelli & Prosdocimi, 1968 for the Southern Cone Lineage, Artemia salina (Linnaeus, 1758) for the Mediterranean-SouthAfrican Lineage, Artemia urmiana Günther, 1899 for the Western Asian Lineage, and Artemia sinica Cai, 1989 for the Eastern Asian Lineage. The name Artemia monica Verrill, 1869 has nomenclatural priority over A. franciscana Kellogg, 1906 for naming the New World Lineage. New synonymies are proposed for A. salina (= C. dybowskii Grochowski, 1896 n. syn., and A. tunisiana Bowen & Sterling, 1978 n. syn.), A. monica (= A. franciscana Kellogg, 1906 n. syn., and A. salina var. pacifica Sars, 1904 n. syn.); A. urmiana (= B. milhausenii Fischer de Waldheim, 1834 n. syn., A. koeppeniana Fischer, 1851 n. syn., A. proxima King, 1855 n. syn., A. s. var. biloba Entz, 1886 n. syn., A. s. var. furcata Entz, 1886 n. syn., A. asiatica Walter, 1887 n. syn., A. parthenogenetica Bowen & Sterling, 1978 n. syn., A. ebinurica Qian & Wang, 1992 n. syn., A. murae Naganawa, 2017 n. syn., and A. frameshifta Naganawa & Mura, 2017 n. syn.). Internal deep nuclear structuring within the A. monica and A. salina clades, might suggest the existence of additional evolutionary units within these taxa.

Untangling the relationship between morphological evolution and lineage diversification is key to explain global patterns of phenotypic disparity across the Tree of Life. Few studies have examined the relationship between high morphological disparity and extinction. In this study, we infer phylogenetic relationships and lineage divergence times within Eupomphini (Meloidae), a tribe of blister beetles endemic to the arid zone of North America, which exhibits a puzzling pattern of very low species richness but wild variation in morphological diversity across extant taxa. Using Bayesian and maximum likelihood inference, we estimate diversification and phenotypic evolutionary rates and infer the time and magnitude of extinction rate shifts and mass extinction events. Our results suggest that Eupomphini underwent an event of ancient radiation coupled with rapid morphological change, possibly linked to the loss of the evolutionary constraint in the elytral shape.Subsequent a high extinction background associated to Miocene-Pliocene transition decimated the diversity within each major clade, resulting in the species-poor genera observed today. Our study supports a connection between high extinction rates and patterns of decoupled phenotypic evolution and lineage diversification, and the possibility of a radiation in the absence of ecological release.

The host range of parasitoids varies greatly among species: Some only parasitize one to a few hosts (specialists), while others parasitize multiple species or a variety of host types (generalists). The direction of most host range shifts in parasitoid groups, that is from generalist to specialist or, alternatively, from specialist to generalist, is unknown. To explore the origin of host range shifts, we studied a clade within the genus Torymus (Hymenoptera, Chalcidoidea) that includes both generalist and specialist parasitoids of Cynipidae (Hymenoptera). We analysed the phylogenetic relationships of the species of Torymus on the basis of two gene fragments (cox1 and ITS2) of 246 specimens and performed an ancestral state reconstruction of the specialist/generalist trait. Our results revealed the following: (a) The ancestral state of this group of Torymus is specialist, with the generalist state evolving through a loss of specialization. (b) The species Torymus cyaneus and Torymus flavipes both have a strong genetic structure, suggesting the existence of different biological identities. (c) There has been a host plant shift in the lineage(s) leading to Torymus rubi and Torymus bedeguaris from galls on Quercus to those on Rosaceae. (d) The alien species Torymus sinensis and the native European species Torymus notatus are phylogenetically closely related. (e) Speciation within Torymus was likely associated with the diversification of their cynipid hosts, which itself was driven by the dramatic changes in climate and vegetation that occurred during the Miocene.