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.
UCE Phylogenomics of New World Cryptopone (Hymenoptera: Formicidae) Elucidates Genus Boundaries, Species Boundaries, and the Vicariant History of a Temperate–Tropical Disjunction
Abstract The genus Cryptopone Emery contains 25 species of litter and soil ants, 5 of which occur in the Americas. Cryptopone gilva (Roger) occurs in the southeastern United States and cloud forests of Mesoamerica, exhibiting an uncommon biogeographic disjunction observed most often in plants. We used phylogenomic data from ultraconserved elements (UCEs), as well as mitogenomes and legacy markers, to investigate phylogenetic relationships, species boundaries, and divergence dates among New World Cryptopone. Species delimitation was conducted using a standard approach and then tested using model-based molecular methods (SNAPP, BPP, SODA, and bPTP). We found that Cryptopone as currently constituted is polyphyletic, and that all the South American species belong to Wadeura Weber, a separate genus unrelated to Cryptopone. A single clade of true Cryptopone occurs in the Americas, restricted to North and Central America. This clade is composed of four species that originated ~4.2 million years ago. One species from the mountains of Guatemala is sister to the other three, favoring a vicariance hypothesis of diversification. The taxonomy of the New World Cryptopone and Wadeura is revised. Taxonomic changes are as follows: Wadeura Weber is resurrected, with new combinations W. guianensis Weber, W. holmgreni (Wheeler), and W. pauli (Fernandes & Delabie); C. guatemalensis (Forel) (rev. stat.) is raised to species and includes C. obsoleta (Menozzi) (syn. nov.). The following new species are described: Cryptopone gilvagrande, C. gilvatumida, and Wadeura holmgrenita. Cryptopone hartwigi Arnold is transferred to Fisheropone Schmidt and Shattuck (n. comb.). Cryptopone mirabilis (Mackay & Mackay 2010) is a junior synonym of Centromyrmex brachycola (Roger) (syn. nov.).
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- Award ID(s):
- 1932405
- NSF-PAR ID:
- 10355522
- Editor(s):
- Sosa-Calvo, Jeffrey
- Date Published:
- Journal Name:
- Insect Systematics and Diversity
- Volume:
- 6
- Issue:
- 1
- ISSN:
- 2399-3421
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract -
The Camponotus subgenus Myrmosaga subgen. rev. from the Malagasy region is revised based on analysis of both qualitative morphological characters and morphometric traits. The multivariate analysis used the Nest Centroid (NC)-clustering method to generate species hypotheses based on 19 continuous morphological traits of minor workers. The proposed species hypotheses were confirmed by cumulative Linear Discriminant Analysis (LDA). Morphometric ratios for the subsets of minor and major workers were used in species descriptions and redefinitions. The present study places the subgenus Myrmopytia syn. nov. in synonymy to Myrmosaga . It recognizes 38 species, of which 19 are newly described: C. aina sp. nov. , C. aro sp. nov. , C. asara sp. nov. , C. atimo sp. nov. , C. bemaheva sp. nov. , C. bozaka sp. nov. , C. daraina sp. nov. , C. harenarum sp. nov. , C. joany sp. nov. , C. karsti sp. nov. , C. kelimaso sp. nov. , C. lokobe sp. nov. , C. mahafaly sp. nov. , C. niavo sp. nov. , C. rotrae sp. nov. , C. sambiranoensis sp. nov. , C. tapia sp. nov. , C. tendryi sp. nov. , C. vano sp. nov. Eleven species are redescribed: C. aurosus Roger, C. cervicalis Roger, C. dufouri Forel, C. gibber Forel, C. hagensii Forel, C. hova Forel, C. hovahovoides Forel, C. immaculatus Forel, C. quadrimaculatus Forel, C. roeseli Forel, C. strangulatus Santschi. The following are raised to species and redescribed: C. becki Santschi stat. nov. , C. boivini Forel stat. rev. , C. cemeryi Özdikmen stat. rev. , C. mixtellus Forel stat. nov. , C. radamae Forel stat. nov. Camponotus maculatus st. fairmairei Santschi syn. nov. , is synonymized under C. boivini . The following are synonymized under C. cervicalis : Camponotus cervicalis gaullei Santschi, syn. nov. ; Camponotus perroti Forel, syn. nov. ; Camponotus perroti aeschylus Forel, syn. nov. ; Camponotus gerberti Donisthorpe, syn. nov. Camponotus dufouri imerinensis Forel, syn. nov. is a synonym of C. dufouri , Camponotus hova var. obscuratus Emery, syn. nov. is a synonym of C. hova , Camponotus quadrimaculatus opacata Emery, syn. nov. is a synonym of C. immaculatus , Camponotus maculatus st. legionarium Santschi, syn. nov. is a synonym of C. roeseli , Camponotus hova maculatoides Emery, syn. nov. is a synonym of C. strangulatus . The following are synonymized under C. quadrimaculatus : Camponotus kelleri Forel, syn. nov. , Camponotus kelleri var. invalidus Forel, syn. nov. , Camponotus quadrimaculatus sellaris Emery, syn. nov. As C. imitator Forel, C. liandia Rakotonirina & Fisher, and C. lubbocki Forel have been recently described and redescribed, only diagnoses and taxonomic discussions are provided. This revision also includes an illustrated species identification key, taxonomic discussions, images, and distribution maps for each species superimposed on the ecoregions of Madagascar.more » « less
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Hines, Heather (Ed.)Abstract The ant genus Syscia Roger, 1861 is part of the cryptic ant fauna inhabiting leaf litter and rotten wood in the Asian and American tropics. It is a distinct clade within the Dorylinae, the subfamily from which army ants arose. Prior to this work, the genus comprised seven species, each known from a single or very few collections. Extensive collecting in Middle America revealed an unexpected and challenging diversity of morphological forms. Locally distinct forms could be identified at many sites, but assignment of specimens to species spanning multiple sites was problematic. To improve species delimitation, Ultra-Conserved Element (UCE) phylogenomic data were sequenced for all forms, both within and among sites, and a phylogeny was inferred. Informed by phylogeny, species delimitation was based on monophyly, absence of within-clade sympatry, and a subjective degree of morphological uniformity. UCE phylogenomic results for 130 specimens were complemented by analysis of mitochondrial COI (DNA barcode) data for an expanded taxon set. The resulting taxonomy augments the number of known species in the New World from 3 to 57. We describe and name 31 new species, and 23 species are assigned morphospecies codes pending improved specimen coverage. Queens may be fully alate or brachypterous, and there is a wide variety of intercaste female forms. Identification based on morphology alone is very difficult due to continuous character variation and high similarity of phylogenetically distant species. An identification aid is provided in the form of a set of distribution maps and standard views, with species ordered by size.more » « less
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- Journal Article:
- https://doi.org/10.1093/isd/ixab031
