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Aim: Latitudinal clines of species diversity are widely documented in terrestrial and marine ecosystems. However, the processes governing species diversity gradients in riverine ecosystems have not been well‐studied. We addressed this issue by comparing species diversity between riverine aquatic and terrestrial earthworm groups (genus Sparganophilus and Diplocardia, respectively). Location: North American temperate zone. Taxon: Sparganophilus and Diplocardia. Methods: We collected 556 Sparganophilus earthworms from 64 sites spanning 27 degrees of latitude (18.77°–45.90°N), and 165 Diplocardia earthworms from 23 sites (21 degrees, 19.77°–41.20°N). We split potential species from the phylogenetic trees based on four genes and compared the latitudinal pattern of species diversity between these two groups. Results: We estimated the number of potential species to be 10 for Sparganophilus and 8 for Diplocardia, respectively, from 526 haplotypes (403 in Sparganophilus and 123 in Diplocardia). Sparganophilus species diversity was higher at mid‐latitudes (32° to 40°) due to a preponderance of species with limited geographical distributions, whereas all specimens collected north of 40° belonged to broadly distributed species. Species with limited geographical distributions were more often collected at higher elevations than broadly distributed species in Sparganophilus. For Diplocardia, species diversity was higher at lower latitudes (28° to 32°). Main Conclusions: These results suggest that, in Sparganophilus, species composition at higher latitudes above 40° is derived from range expansion by broadly distributed species from lower latitudes. The high elevation area in the native distribution range of Sparganophilus is limited to the Appalachian Mountains, which ranges above 33° in latitude. The high species diversity of Sparganophilus with limited distributions at mid‐latitude (32°–40°) suggests that the headwater regions at the Appalachian Mountains are sites for more frequent speciation. [ABSTRACT FROM AUTHOR]

Carex sect. Confertiflorae s.l. is a medium‐sized species group (ca. 40 species) with its center of diversity in E Asia (China and Japan). According to morphological traits, the section has been proposed to split into two sections (sects. Confertiflorae sensu Ohwi and Molliculae Ohwi) up to five different ones (sects. Confertiflorae s.s., Molliculae, Dispalatae Ohwi, Ischnostachyae Ohwi, and Alliiformes Akiyama). Recent phylogenetic reconstructions showed Confertiflorae s.l. not to be monophyletic, as species traditionally considered part of it were found to belong to other clades, whereas species traditionally ascribed to other sections were nested within it. In this study, we investigated the phylogenetic structure, morphological affinities, and biogeographic history of sect. Confertiflorae s.l. We employed a taxon‐based approach to explore the morphological affinities of the species considered in sect. Confertiflorae and compared the micromorphology of the nutlets of almost all the taxa using SEM. We included 40 samples representing 31 species/subspecies of sect. Confertiflorae s.l. and used two nuclear (ETS and ITS) and three plastid (trnL‐F, matK, and rpl32‐trnLUAG) molecular markers to reconstruct the phylogeny of the group. The phylogenetic analyses confirmed the polyphyly of sect. Confertiflorae s.l., whose representatives were found within five distinct clades. From these, two clades, sect. Confertiflorae and sect. Molliculae, were found to be closely related and contained the majority of the species. The composition of the two clades agreed with the morphological structure of the group, and we confirmed an exclusive combination of features (namely color of basal sheaths, presence of bract sheath, peduncle of lowest spike, inflorescence sex distribution, shape of pistillate glume apex, and color and veins of utricle, among others) characterizing each of the two clades. The origin of the two clades was found to be in the early Pliocene; however, the majority of the diversification events within each clade took place during the Pleistocene. This illustrates that although Asia has been regarded as having little potential ecological space for Carex to diversify due to its climate stability, groups of sedges sub‐endemic from that area may have a fairly recent origin related to glaciations. We proposed the rearrangement of sect. Confertiflorae as previously conceived as three independent sections: the monotypic Alliiformes, sect. Molliculae, and sect. Paludosae. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carabinae ground beetles occur on all continents except Antarctica. • Their evolutionary history was studied using ultraconserved element sequence data. • Dispersal occurred during the Cretaceous and since the Oligocene. • Ancestors were winged, and loss of flight occurred in multiple lineages in parallel. • Marked species diversification occurred in a flightless lineage in Eurasia. The origin and diversification process of lineages of organisms that are currently widely distributed among continents is an interesting subject for exploring the evolutionary history of global species diversity. Ground beetles of the subfamily Carabinae are flightless except for one lineage, but nevertheless occur on all continents except Antarctica. Here, we used sequence data from ultraconserved elements to reconstruct the phylogeny, divergence time, biogeographical history, ancestral state of hind wings and changes in the speciation rate of Carabinae. Our results show that Carabinae originated in the Americas and diversified into four tribes during the period from the late Jurassic to the late Cretaceous, with two in South America (Celoglossini) and Australasia (Pamborini) and two in Laurasia (Cychrini and Carabini). The ancestral Carabinae were inferred to be winged; three of four tribes (Cychrini, Ceglossini and Pamborini) have completely lost their hind wings and flight capability. The remaining tribe, Carabini, diverged into the subtribes Carabina (wingless) and Calosomina (winged) in the Oligocene. Carabina originated in Europe, spread over Eurasia and diversified into approximately 1000 species, accounting for around 60% of all Carabinae species. Calosomina that were flight-capable dispersed from North America or Eurasia to South America, Australia, and Africa, and then flightless lineages evolved on oceanic islands and continental highlands. The speciation rate increased in the Cychrini and Carabini clades in Eurasia. Within Carabini, the speciation rate was higher for wingless than winged states. Our study showed that the global distribution of Carabinae resulted from ancient dispersal before the breakup of Gondwana and more recent dispersal through flight around the world. These patterns consequently illustrate the causal relationships of geographical history, evolution of flightlessness, and the global distribution and species diversity of Carabinae. [ABSTRACT FROM AUTHOR]

Some highly isolated oceanic islands harbour endemic ground beetles that have lost the ability to fly. Here, we investigated the origin of the possibly extinct flightless giant ground beetle Aplothorax burchelli on St Helena Island in the South Atlantic. Aplothorax burchelli was initially considered to be a member of the subtribe Calosomina (=genus Calosoma) of the subfamily Carabinae (Coleoptera: Carabidae) closely related to the genus Ctenosta (= Calosoma subgenus Ctenosta), but this proposition was questioned due to its unique external and genital morphology. We conducted a phylogenetic analysis of mitogenome sequences using historical specimens of A. burchelli and samples of representative species of Carabinae. Our analysis of 13 protein-coding gene sequences revealed that A. burchelli is definitely a member of Calosomina, most closely related to a species of Ctenosta. Further analysis using NADH dehydrogenase subunit 5 gene sequences from most groups in Calosomina showed that A. burchelli formed a monophyletic group with Ctenosta species from Africa and Madagascar. Our results suggest that the ancestor of A. burchelli , which had the ability to fly, colonized St Helena from Africa after the emergence of the island 14 Mya, and has since undergone evolutionary changes in conjunction with loss of flight. [ABSTRACT FROM AUTHOR]