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We investigate the species-level taxonomy and evolutionary history of Nearctic ants in the Crematogaster scutellaris group (Hymenoptera: Formicidae), drawing on evidence from morphology and UCE (ultraconserved element) phylogenomics. The New World species in this group form a well-supported clade that originated in the Late Miocene (~7.3 Mya) and subsequently diverged into three major lineages: the C. coarctata clade (south-western Nearctic), the C. opaca clade (south-western Nearctic and northern Neotropics) and the C. lineolata clade (eastern Nearctic and Caribbean, with four isolated south-west endemics). We hypothesize trans-Beringian dispersal into the New World, west-to-east movement within North America and restriction of mesophilic species to the east with increasing aridification of the west. The ancestral nesting behaviour of these ants is inferred to be ground-dwelling, and this is still the predominant condition in the arid west, whereas most species in the eastern United States are arboreal. We resurrect from synonymy nine species and describe three new species: C. detecta sp. nov. (from Nevada), C. parapilosa sp. nov. (Florida) and C. vetusta sp. nov. (Arizona). We provide a worker-based key to the 34 species of Crematogaster occurring in America north of Mexico, but emphasize that there are still ongoing taxonomic issues that need to be resolved.

 

Using genetic, morphological, and geographical evidence, we investigate the species-level taxonomy and evolutionary history of the Pseudomyrmex elongatulus group, a clade of ants distributed from southwestern United States to Costa Rica. Through targeted enrichment of 2,524 UCE (ultraconserved element) loci we generate a phylogenomic data set and clarify the phylogenetic relationships and biogeographic history of these ants. The crown group is estimated to have originated ~8 Ma, in Mexico and/or northern Central America, and subsequently expanded into southern Central America and the southwestern Nearctic. The P. elongatulus group contains a mix of low- and high-elevation species, and there were apparently multiple transitions between these habitat types. We uncover three examples of one species—of restricted or marginal geographical distribution—being embedded phylogenetically in another species, rendering the latter paraphyletic. One of these cases involves an apparent workerless social parasite that occurs sympatrically with its parent species, with the latter serving as host. This suggests a sympatric origin of the parasite species within the distribution range of its host. Species boundaries are tested using three molecular delimitation approaches (SODA, bPTP, BPP) but these methods generate inflated species estimates (26–46 species), evidently because of a failure to distinguish population structure from species differences. In a formal taxonomic revision of the P. elongatulus group, based on almost 3,000 specimens from ~625 localities, we allow for geographic variation within species and we employ distinctness-in-sympatry criteria for testing hypotheses about species limits. Under these guidelines we recognize 13 species, of which nine are new: P. arcanus, sp. nov. (western Mexico); P. capillatus, sp. nov. (western Mexico); P. cognatus, sp. nov. (Chiapas, Mexico to Nicaragua); P. comitator, sp. nov. (Chiapas, Mexico); P. ereptor, sp. nov. (Veracruz, Mexico); P. exoratus, sp. nov. (southeastern Mexico, Honduras); P. fasciatus, sp. nov. (Chiapas, Mexico to Costa Rica); P. nimbus, sp. nov. (Costa Rica); and P. veracruzensis, sp. nov. (Veracruz, Mexico). Our study highlights the value of combining phylogenomic, phenotypic, and geographical data to resolve taxonomic and evolutionary questions.

 

A high-resolution map of ant diversity allows an assessment of how well biodiversity centers overlap across taxa. 

The arboreal ant genus Tetraponera is widely distributed in the Paleotropics. Five species groups were previously recognized in the Afrotropical region (including Madagascar), and two of these were revised. This paper provides a taxonomic treatment of the remaining species. A survey of the T. allaborans group on the African mainland leads to the recognition of fourteen species: T. clypeata (Emery) (= T. braunsi (Forel) syn. nov.); T. continua (Forel) (= T. claveaui (Santschi) syn. nov.); T. cortina sp. nov.; T. dispar sp. nov.; T. emeryi (Forel) (= T. braunsi durbanensis (Forel) syn. nov.); T. exactor sp. nov.; T. furtiva sp. nov.; T. gerdae (Stitz); T. liengmei (Forel); T. mayri (Forel); T. pedana sp. nov.; T. penzigi (Mayr) (= T. scotti Donisthorpe syn. nov. = T. zavattarii (Menozzi) syn. nov. = T. penzigi praestigiatrix Santschi syn. nov.); T. pumila sp. nov.; and T. tessmanni (Stitz). A full revision of the Malagasy species of the T. allaborans group is deferred, but the following new synonymy is established: T. hysterica (Forel) = T. hysterica inflata (Emery) syn. nov.; T. longula (Emery) = T. sahlbergii deplanata (Forel) syn. nov.; T. mandibularis (Emery) = T. flexuosa (Santschi) syn. nov.; T. morondaviensis (Forel) = T. arrogans (Santschi) syn. nov. = T. demens (Santschi) syn. nov. = T. hysterica dimidiata (Forel) syn. nov.; and T. sahlbergii = T. sahlbergii spuria (Forel) syn. nov. = T. plicatidens (Santschi) syn. nov. In the T. ambigua group the following synonymy is reinstated (syn. rev.): T. ambigua (Emery) = T. erythraea (Emery) = T. bifoveolata (Mayr) = T. angolensis Santschi; and T. ophthalmica (Emery) = T. unidens Santschi. A new species is described in the Madagascar-endemic T. grandidieri group: T. elegans sp. nov. Scrutiny of the T. natalensis group indicates the occurrence of ten species: T. andrei (Mayr), T. anthracina (Santschi), T. caffra (Santschi), T. insularis sp. nov., T. kosi sp. nov., T. mocquerysi (André), T. natalensis (F. Smith), T. redacta sp. nov., T. schulthessi (Santschi), and T. setosa sp. nov. T. insularis is known only from Madagascar, while the other nine species are confined to the African mainland. The following new synonymy is proposed for the T. natalensis group (senior synonym cited first): T. anthracina = T. poultoni Donisthorpe syn. nov. = T. triangularis (Stitz) syn. nov.; T. mocquerysi = T. mocquerysi biozellata (Karavaiev) syn. nov. = T. mocquerysi elongata (Stitz) syn. nov. = T. emacerata (Santschi) syn. nov. = T. triangularis illota (Santschi) syn. nov. = T. ledouxi Terron syn. nov. = T. lemoulti (Santschi) syn. nov. = T. mocquerysi lepida Wheeler syn. nov. = T. monardi (Santschi) syn. nov. = T. emacerata oberbecki (Forel) syn. nov. = T. emacerata odiosa (Forel) syn. nov.; and T. natalensis = T. angusta (Arnold) syn. nov. = T. capensis (F. Smith) syn. nov. = T. natalensis cuitensis (Forel) syn. nov. = T. mocquerysi lutea (Stitz) syn. nov. = T. natalensis obscurata (Emery) syn. nov. = T. prelli (Forel) syn. nov. = T. natalensis usambarensis (Forel) syn. nov. The extensive synonymy under T. mocquerysi and T. natalensis reflects the conviction that previous taxonomists underestimated the extent of intraspecific variation in these taxa, but further study and testing of this conclusion is warranted. An illustrated worker- and queen-based key is provided for all species of Tetraponera occurring in Africa and Madagascar, except the Malagasy members of the T. allaborans group. 

The ant subfamily Leptanillinae (Hymenoptera: Formicidae) consists of minute soil-dwelling species, with several genera within this clade being based solely upon males, including Yavnella Kugler. The dissociation of males and workers has resulted in taxonomic confusion for the Leptanillinae. We here describe the worker caste of Yavnella, facilitated by maximum-likelihood and Bayesian inference from 473 partitioned ultra-conserved element loci, this dataset including 49 other leptanilline species, both described and undescribed. Yavnella laventa sp. nov. is described from seven worker specimens collected in south-western Iran from the Milieu Souterrain Superficiel, a subterranean microhabitat consisting of air-filled cavities among rock and soil fragments, which is subject to similar environmental conditions as caves. This species has bizarrely elongated appendages, which suggests that it is confined to cavities, in contrast with the soil-dwelling behaviour observed in other leptanilline ants. Based on its gracile phenotype relative to other Leptanillinae, Y. laventa shows remarkable adaptations for subterranean life, making it one of a very few examples of this syndrome among the ants. Moreover, the discovery of the worker caste of Yavnella expands our morphological knowledge of the leptanilline ants. We provide worker- and male-based diagnoses of Yavnella, along with a key to the genera of the Leptanillinae for which workers are known. The worker caste of Yavnella as known from this species is immediately recognisable, but the possibility must be noted that described workers of Leptanilla may in fact belong to Yavnella. Further molecular sampling is required to test this hypothesis. ZooBank: urn:lsid:zoobank.org:pub:A54A5766-F35A-4074-9353-1C70FE3955D3 

Abstract Dorymyrmex Mayr 1866, the ‘pyramid ants’ or ‘cone ants’, are conspicuous inhabitants of arid landscapes across the Americas. Ranging from the Great Plains to Patagonia, they are concentrated north and south of the tropics in contrast to the latitudinal diversity gradient canon. Despite being frequently collected and ecologically important, Dorymyrmex ants exemplify the taxonomic neglect typical in the subfamily Dolichoderinae. The genus has never had the benefit of a global revision, and even the major lineages are still uncertain. This work characterizes the issues at hand and ushers 22 Dorymyrmex species into the world of modern-day phylogenomics: By targeting ultraconserved elements (UCEs) across the genome, I construct an alignment of 1,891 loci, infer phylogenies under maximum likelihood and Bayesian approaches, and estimate divergence dates. Three major clades of Dorymyrmex emerge with maximal support, corresponding to former genera: Dorymyrmex sensu stricto, Araucomyrmex Gallardo 1919, and Conomyrma Forel 1913. The pyramicus group (‘Conomyrma’) shows a recent, rapid radiation with minimal morphological differentiation, reaffirming the difficulty of species delimitation in this widespread clade. Finally, I observe a general south-to-north pattern of dispersal, likely by way of savanna ‘stepping stones’ across the tropics during cooler, drier periods. Intercontinental dispersal occurred after the hypothetical Caribbean landspan in the Miocene, but before the Pleistocene or the completion of the Panamanian isthmus, suggesting dispersal by flight. This corroborates patterns observed in other arid-adapted amphitropical New World taxa. Characterizing the major Dorymyrmex species groups is an important first step towards stable taxonomic definitions—which underpin active studies in behavior, chemical ecology, and physiology. 

Camponotus and Colobopsis are widely distributed and species-rich genera in the ant tribe Camponotini. Molecular phylogenetic studies demonstrate that they are not sister taxa, but several lineages within each genus have converged to a remarkable degree, confounding the taxonomy of these ants. Based on multiple lines of evidence, including worker and male morphology, we demonstrate that: (1) three species of “Camponotus” belonging to the subgenus Myrmotemnus, including its type species, are in fact members of the genus Colobopsis ; (2) four species previously assigned to Colobopsis belong to the subgenus Myrmamblys of Camponotus ; and (3) three Nearctic taxa recently placed in Colobopsis are members of the genus Camponotus and closely related to Camponotus clarithorax . These taxonomic findings yield the following new or revived combinations: Colobopsis moeschi ( comb. nov. ), Colobopsis moeschi lygaea ( comb. nov. ), Colobopsis nutans ( comb. nov. ), Colobopsis nutans cleliae ( comb. nov. ), and Colobopsis reichenspergeri ( comb. nov. ); Camponotus apostemata ( comb. nov. ), Camponotus aurelianus ( comb. rev. ), Camponotus cavibregma ( comb. nov. ), Camponotus horrens ( comb. rev. ), Camponotus politae ( comb. rev. ), Camponotus trajanus ( comb. rev. ), and Camponotus yogi ( comb. rev. ). A further consequence is the following generic synonymy (senior synonym listed first): Colobopsis = Myrmotemnus syn. nov. , and Camponotus = Dolophra syn. rev. At the species level, we argue that Camponotus apostemata and Camponotus cavibregma are junior synonyms ( syn. nov. ) of Camponotus yogi , and Camponotus quercicola is a junior synonym ( syn. nov. ) of Ca. laevigatus . Taxonomic comments are also provided on some members of the Camponotus reticulatus group, with Camponotus adustus ( stat. nov. ) and Ca. leucodiscus ( stat. rev. ) being recognized as distinct species rather than subspecies of Ca. bellus . A male-based diagnosis of the Camponotini is provided, and differences between the males of Colobopsis and Camponotus are documented and illustrated for the first time. This study reveals new character systems of potential value to the systematics of these ants, including features of the male genitalia, and emphasizes the value of reciprocal illumination between phylogenomics and critical morphological analysis.