Ant Genus Research Articles

Elektroformica azquil gen. et sp. nov., a new formicine ant from Oligo-Miocene Mexican amber

A novel ant genus and species, Elektroformica azquil gen. et sp. nov. is described from Late Oligocene-Early Miocene Mexican amber. It is placed within the subfamily Formicinae based on the presence of an acidopore. It can be distinguished by its diminutive size, elongated scapes that extend beyond the head’s vertex by approximately double the length of the head, eyes located about 2/3 the distance between the mandible’s base and the head’s vertex. Additional diagnostic features include a distinctive keel-shaped clypeus, a prominently marked promesonotal groove, a discontinuous mesonotum with dorsal and declivitous edges, a curved propodeum lacking differentiated anterior and posterior margins, and a markedly reduced node on a thick petiole. Elektroformica azquil gen. et sp. nov. is in syninclusion with deciduous petals and filaments of a flower identified as cf. Hymenaea mexicana, along with elements closely associated with leaf litter and the soil environment. As an extinct taxon endemic to Oligo-Miocene deposits, Elektroformica azquil gen. et sp. nov. enriches the diversity within the subfamily Formicinae and offers valuable insights into the evolutionary history of formicine ants.

Taxonomy of the Palearctic socially parasitic Temnothorax (Myrmoxenus) ants (Hymenoptera: Formicidae).

The ant genus Temnothorax is one of the most diverse in the Palearctic region, comprising several species with different life histories and uncertain taxonomic backgrounds. Socially parasitic Temnothorax ant species were typically described decades ago, primarily based on traditional morphological traits. In some aspects, these species have come back into the spotlight in recent years, necessitating a comprehensive taxonomic revision of the species of the genus. In this paper, we present a quantitative morphology-based taxonomic revision of the Temnothorax corsicus species group (formerly called Myrmoxenus genus) based on the analysis of 20 continuous morphometric traits collected from 394 worker and 19 traits from 473 gyne individuals belonging to 240 samples. Based on morphometric analyses, we propose junior synonymy for Temnothorax tamarae (Arnol'di, 1968) under T. ravouxi (André, 1896), and T. microcellatus (Soudek, 1925) is revived and is considered a senior synonym of T. menozzii (Finzi, 1924). Detailed descriptions, measurements, distribution, and host usage of all ten species are given. Dichotomous keys to workers, known gynes, and photographs of all species are presented.

Three new species of Pheidole Westwood, 1839 (Hymenoptera: Formicidae: Myrmicinae: Attini) from central Mexico

Pheidole is the richest ant genus in the world. We describe herein three new species from the state of Puebla, Mexico: P. jolalpanensis sp. nov., P. latiscava sp. nov. and P. rojasae sp. nov. Additionally state records and notes are provided for P. lamia Wheeler 1901 and P. polymorpha Wilson 2003 for the Mexican states of Veracruz and Querétaro, respectively. Parts of Wilson’s taxonomic keys are modified to allow the identification of the new species.

“Picking up signals” in male genital morphospace and integrating phylogenomics to delimit Neotropical Nylanderia Emery species (Hymenoptera: Formicidae)

Abstract Genital morphology, a cornerstone in taxonomy that predates Linnaeus’s Systema Naturae, is vital for species delimitation. However, the widely accepted paradigm that genitalia are taxonomically informative lacks robust testing between closely related species, and supporting evidence is often limited to taxonomic literature in which genitalia are assumed a priori to be species-specific. The cosmopolitan ant genus Nylanderia Emery includes 123 described species, with most in the Neotropics still undescribed. Workers are often morphologically cryptic, and males are rare in collections but required for morphological delimitation. Using Ultraconserved Elements (UCEs) from 236 samples, including 53 Neotropical Nylanderia species, we reconstructed a phylogenetic framework to compare the genitalia (gonopods) of males collected alongside workers. We used geometric morphometrics on images of slide-mounted genitalia from 16 species and nano-CT scans of Nylanderia fulva (Mayr) and Nylanderia pubens (Forel) genital capsules and interpreted results considering phylogeny under maximum likelihood and the multispecies coalescent. We found strong morphological and molecular support for 2 distantly related American clades, identifiable by gonopod shape, with significant differences observed among most species. Three previously reported COI clades of N. fulva were not supported as monophyletic, nor were their gonopods significantly different. However, N. pubens was supported as distinct by all phylogenetic and 3DGM results. Our findings emphasize the importance of male genitalia for delimiting species boundaries and revising Neotropical Nylanderia. Given their importance, particularly in morphologically cryptic taxa, we recommend a greater focus on linking male and worker phenotypes, which can be facilitated through comprehensive nest series collection.

Chromosomal diversity in Crematogaster Lund, 1831 (Formicidae: Myrmicinae) from the Amazon rainforest.

Crematogaster Lund, 1831 is a speciose ant genus globally distributed and easily recognizable. Although biogeographical theories explain some variation among Neotropical Crematogaster, several taxonomical issues remain unresolved. While cytogenetic approaches can help to delimit species, cytogenetic data are only available for 18 taxa. In this study, classical and molecular cytogenetic analyses were performed on five Crematogaster species from the Brazilian Amazon to identify species-specific patterns. Two different cytotypes, both with 2n=22 chromosomes were observed in Crematogaster erecta Mayr, 1866, suggesting the presence of cryptic species, although with different karyotypic formulas. Crematogaster aff. erecta had 2n=28, while C. limata Smith, 1858, C. tenuicula Forel, 1904 and Crematogaster sp. had 2n = 38. The telomeric motif (TTAGG)n was found in all five species, and the (TCAGG)n motif was detected in the telomeres of C. limata. This peculiar motif was also detected in the centromeric regions of C. erecta cytotype I. The microsatellite (GA)n was dispersed in the chromosomes of all species studied which also had a single intrachromosomal rDNA site. The cytogenetic results revealed notable interspecific and intraspecific variation, which suggests different chromosomal rearrangements involved in the origin of these variations, also highlighting the taxonomic value of cytogenetic data on Crematogaster.

A new species of yellow acorn ant discovered in Italy via integrative taxonomy (Temnothorax luteus-complex, Formicidae)

The Mediterranean, a global hotspot for rare ant species, hosts a significant representation of the global diversity of the mainly Holarctic ant genus Temnothorax. However, several groups still require significant taxonomic efforts. The taxonomy of the T. luteus complex species was revised in 2014 when morphometrics allowed distinguishing two valid species and two synonyms out of four taxa that had been originally described from France. The two species recognized since then are T. luteus, distributed from Iberia to the Alps, and the largely sympatric but much more xerothermophilic T. racovitzai. In Italy, only a few records of the complex were ever published, and the identity of the Italian population was never thoroughly assessed. We combined morphometrics with phylogenomic data to assess the identity of the T. luteus populations that spanned from Sicily to the Italian Alps and discovered that all Italian samples belong to a new cryptic species, which we describe as T. apenninicussp. nov. whose glacial refugium was probably in the southern Apennines.

A new species of the Ant Genus Leptanilla Emery, 1870 (Hymenoptera: Formicidae) from sichuan Province, China

A new species of the Ant Genus Leptanilla Emery, 1870 (Hymenoptera: Formicidae) from sichuan Province, China

Ant impacts on global patterns of bird elevational diversity.

Using data on bird species elevational distributions from the world's mountain ranges, bird diets, and the distribution of the ant genus Oecophylla, we report that global patterns in bird elevational diversity show signals of competition with ants. Oecophylla is an abundant and effective predator of invertebrates, preying on the same species that invertivorous birds feed on. In mountain ranges with Oecophylla present in the foothills, the maximum species richness of invertivorous birds (but not other trophic guilds) occurs, on average, at 960 m, ca. 450 m higher than in mountain ranges without Oecophylla, resulting in a mid-elevation peak in bird species richness. Where Oecophylla is absent, bird species richness for all guilds generally show monotonic declines with increasing elevation. We argue that Oecophylla reduces prey density for invertivorous birds and that low prey abundance reduces invertivorous bird density, which in turn is correlated with lower bird species richness. These findngs suggest that competition between distantly related taxa can set range limits, leading to emergent diversity patterns over large scales.

Four new inquiline social parasite species in the dolichoderine ant genus Tapinoma (Hymenoptera, Formicidae).

Four new inquiline social parasites are described in the dolichoderine ant genus Tapinoma from the Nearctic region, and keys are provided for queens and males of the Nearctic Tapinoma species. The new social parasite species represent the first inquiline species in the genus Tapinoma and the first confirmed inquilines known from the ant subfamily Dolichoderinae. The four new species appear to be workerless inquilines that exploit a single host, Tapinomasessile (Say), and they represent at least two distinct life history syndromes. Tapinomaincognitum Cover & Rabeling, sp. nov. is highly derived morphologically and is a host-queen-tolerant inquiline. In contrast, T.inflatiscapus Cover & Rabeling, sp. nov. shows a lesser degree of morphological modification and appears to be a host-queen-intolerant social parasite. The life history of T.pulchellum Cover & Rabeling, sp. nov. is presently unknown, but its close similarity to T.incognitum suggests that it is also a host-queen-tolerant inquiline. The life history of T.shattucki Cover & Rabeling, sp. nov. is still uncertain. Our findings provide novel insights into the complex biology of ant inquiline life history syndromes.

Review of the ant genus Manica (Hymenoptera, Formicidae), with a new record of the genus in China and description of a new species

Seven known extant species of Manica have been identified worldwide: M. bradleyi (Wheeler, 1909), M. hunteri (Wheeler, 1914), M. invidia Bolton, 1995, M. parasitica (Creighton, 1934), M. rubida (Latreille, 1802), M. shanyiisp. nov., and M. yessensis Azuma, 1955. The discovery of the new species is documented from Sichuan Province, China, marking the first recorded instance of the genus Manica in China. Additionally, an identification key for distinguishing the known species within the genus Manica is provided.

Solenopsis abdita Thompson (Formicidae: Myrmicinae) new to Britain

The ant genus Solenopsis Westwood, 1840, includes over 200 currently recognised species and subspecies. About 20 larger predatory species are called 'fire ants', while the rest are mostly small, inconspicuous species commonly known as 'thief ants'. Several fire ant species have established populations outside their native Solenopsis ranges, where they can be a major pest, e. g., the Red imported fire ant (S. invicta Buren, 1972). In contrast, few thief ants have been recorded outside their native ranges and none are known as significant pests. Here, we report a New World (Florida) thief ant, Solenopsis abdita Thompson, 1989, with an established population in the artificially-heated greenhouse at The Eden Project, Cornwall, England. This is the earliest known record of S. abdita in Europe. We provide a suite of measurements, high-resolution images, and diagnostic morphological characters useful to help others identify this species.

First Record of the Rare Ant Genus Cylindromyrmex 1 Mayr in Quintana Roo, Mexico

First Record of the Rare Ant Genus Cylindromyrmex 1 Mayr in Quintana Roo, Mexico

A taxonomic revision of the Palaearctic species of the ant genus Tapinoma Mayr 1861 (Hymenoptera: Formicidae)

A taxonomic revision of the Palaearctic species of the ant genus Tapinoma Emery 1861 is provided. Due to the extreme rarity of discernable characters, the female castes of 64% of the species are not separable by primary visual perception of an expert and are thus truly cryptic. The main working rationale of the revision is Numeric Morphology-Based Alpha-Taxonomy (NUMOBAT) with formation of species hypotheses largely based on exploratory data analyses and checking these hypotheses by discriminant analysis. NUMOBAT data of all considered species comprise 648 worker samples with 2014 individuals and 30,000 primary data. Species are depicted by z-stack imaging in three standard visual positions. Numeric data on 15 phenotypical characters are presented in comparative tables and supplementary verbal descriptions are given. Analysis of nuclear DNA was based on evaluation of 15 microsatellite loci in 274 nest samples. The NUMOBAT-based classification of eight species of the Tapinoma nigerrimum and T. simrothi group which are inseparable by subjective visual inspection was confirmed by nuclear DNA data in 98.3% of 169 samples where both morphological and nuDNA data were available. The three cases of disagreement between NUMOBAT and nuDNA classification were discussed. Excluding Nomina Nuda and unavailable names, the revision recognized 34 available names which divide into 21 valid species, 11 junior synonyms and two names placed under Incertae Sedis. Four species are described as new: Tapinoma hispanicum n. sp., T. insularis n. sp., T. dabashanica n. sp. and T. sichuense n. sp. The following synonymies were stated: T. collina Foerster 1850, T. erraticum platyops Emery 1925 and T. erraticum bononiensis Emery 1925 as synonyms of T. erraticum (Latreille 1798); T. tauridis Emery 1925 and T. breve Emery 1925 as synonyms of T. glabrella (Nylander 1849) that is erected to species level; T. minor Bernard 1945 as synonym of T. simrothi Krausse-Heldrungen 1911; T. simrothi azerbaidzhanica Karavajev 1932 as synonym of Tapinoma karavaievi Emery 1925 that is erected here to species level; T. erraticum ambiguum Emery 1925 as synonym of T. madeirense Forel 1895 and T. emeryanum Kuznetzov-Ugamsky 1927 as synonym of T. sinense Emery 1925. Despite an insufficient separation of the female castes of Tapinoma madeirense and T. subboreale Seifert 2011 by NUMOBAT characters and detection of a hybrid zone in southern France, the heterospecific status of the two taxa was maintained based on sufficient differences in male genitalia and of nuclear DNA over a larger geographic scale. Formica caerulescens Losana 1834 is removed from genus Tapinoma and recognized as member of the subfamily Formicinae.

Diel Patterns Hold Promise as an Ecological Trait for Ants

Ecological traits have flourished in insect-based studies, resulting in a substantial and growing list of measurable traits. One trait that will likely become more attractive as data quality and curation improve is the diel patterns of insect activities. Diel patterns in ants can help better understand vital ecological processes such as competition and invasion biology. Because diel activity has the potential to be an informative trait in ants, we assessed the diel designations of foraging ants across the literature to quantify and assess the variation and sampling extent of this particular trait. We collected diel designations from 104 peer-reviewed scientific articles and quantified these data across important and documented ecological traits. We found that a disproportionate amount of solitary foraging ants were primarily diurnal foragers relative to ants that cooperatively forage. Our data show that diel patterns in foraging vary widely within and across ant genera. Importantly, we highlight the undersampling of this crucial ecological trait, which currently limits its utility. Our efforts highlight the importance of assessing an ecologically important trait’s landscape of reported data.

Strumigenys emmae (Emery, 1890) (Myrmicinae) new to Britain, with an updated key to the known Strumigenys of the West Palaearctic.

The ant genus Strumigenys is a hyper diverse pantropical group of specialised predatory leaf litter dwelling ants. Species richness peaks within tropics, with few species extending into the West Palaearctic realm. A significant proportion of Strumigenys species known from the West Palaearctic are non-native, spread via human commerce, and predominately establishing populations within artificially heated greenhouses. In Britain, two Strumigenys species were previously known, S. rogeri Emery, 1890 and S. perplexa (Smith, 1876). Here we add a third species, S. emmae (Emery, 1890) based upon specimens from the humid tropical biomes at the Eden Project, Cornwall (UK). A single record outlined here is noted as the earliest known record of S. emmae from Europe thus far, pre-dating previous records by four years. We provide high resolution images, measurements, and discussion on the ecology of the species. In addition, an updated key to the Strumigenys of the Europe is supplied.

Peptide toxins that target vertebrate voltage-gated sodium channels underly the painful stings of harvester ants

Harvester ants (genus Pogonomyrmex) are renowned for their stings which cause intense, long-lasting pain, and other neurotoxic symptoms in vertebrates. Here, we show that harvester ant venoms are relatively simple and composed largely of peptide toxins. One class of peptides is primarily responsible for the long-lasting local pain of envenomation via activation of peripheral sensory neurons. These hydrophobic, cysteine-free peptides potently modulate mammalian voltage-gated sodium (NaV) channels, reducing the voltage threshold for activation and inhibiting channel inactivation. These toxins appear to have evolved specifically to deter vertebrates.

Out of the desert: Paleoclimatic changes drove the diversification of arid-adapted Ocymyrmex ants in southern Africa

A highly endemic ant fauna is found in the arid regions of southern Africa, including species in the genus Ocymyrmex. This genus of ants has higher species richness in the western arid regions of southern Africa compared to tropical and subtropical parts of the continent. The processes that have produced these patterns of diversity and distribution of arid adapted ants in southern Africa have never been investigated. The diversification of many other taxa in the region has been associated with past climate fluctuations that occurred during the Miocene epoch. In this study, the nature and timing of historical processes that may have led to the diversification within Ocymyrmex were assessed. We hypothesized that past climate oscillations, characterized by long periods of aridification, have driven the current distribution of Ocymyrmex species that resulted in the highest species richness of the genus in the Deserts & xeric shrublands biome in southern Africa.Ninety-four Ocymyrmex worker specimens from Botswana, Kenya, Namibia, South Africa, Tanzania and Zimbabwe, representing 21 currently described species and six morphospecies, were included in a phylogenomic analysis. Phylogenies for the genus, based on next generation sequencing data from ultraconserved elements, were inferred using Maximum Likelihood, and a dating analysis was performed using secondary age estimates as calibration points. A distribution database of Ocymyrmex records was used to assign species ranges, which were then coded according to major biomes in southern Africa and used as input for biogeographical analysis. We explored the phylogenomic relationships of Ocymyrmex and analysed these within a biogeographical and paleoclimatic framework to disentangle the potential processes responsible for diversification in this group. Dating analyses estimated that the crown age of Ocymyrmex dates to the Oligocene, around 32 Ma. Diversification within this group occurred between the mid-Miocene (∼12.5 Ma) and Pleistocene (∼2 Ma). Our biogeographic analyses suggest that Ocymyrmex species originated in the south-western region of southern Africa, which is now part of the Deserts & xeric shrublands biome and diversified into eastern subtropical areas during the Pliocene. Paleoclimatic changes resulting in increased aridity during the Miocene likely drove the diversification of the genus Ocymyrmex. It is most likely that the diversification of grasslands, because of historical climate change, facilitated the diversification of these ants to the eastern parts of southern Africa when open grasslands replaced forests during the early Miocene.

Overview of the ant genus Vollenhovia (Hymenoptera, Formicidae) in India and Sri Lanka, with an illustrated key and the description of a new species

The ant genus Vollenhovia Mayr, 1865 (Myrmicinae, Crematogastrini) mostly occurs in the Australasian and Oriental regions. We revised its diversity in India and Sri Lanka based on qualitative and quantitative morphology, recognizing eleven taxa, including a new species which is described herewith: V. escherichi Forel, 1911, V. gastropunctata Bharti & Kumar, 2013, V. karimalaensis Dhadwal et al., 2023, V. keralensis Kripakaran & Sadasivan, 2022, V. mawrapensis Dhadwal et al., 2023, V. oblonga laevithorax Emery, 1889, V. penetrans (Smith, 1857), V. pfeifferi Bharti et al., 2023, V. taylori Rilta et al., 2023, V. terayamai Rilta et al., 2023, and V. yasmeenae sp. nov. The subspecies status of V. oblonga laevithorax and its relationship with V. penetrans, whose type series does not contain workers, still requires to be assessed in the context of a broader revision including the whole Oriental region. The known distribution of the genus in the Indian subcontinent appears to be fragmentary, still requiring extensive sampling efforts. Four species are from the Western Ghats biodiversity hotspot in the southern Indian state of Kerala, one is endemic to the biogeographically related Sri Lanka, three are known from Eastern India near the border with Bangladesh, two are reported from the Andaman and Nicobar Islands, and one is restricted to the Himachal Pradesh in northern India. A comprehensive key of the known Vollenhovia species from India and Sri Lanka is provided.

Further additions to the knowledge of Strumigenys (Formicidae: Myrmicinae) within South East Asia, with the descriptions of 20 new species

The species of the ant genus Strumigenys Smith, 1860 from Southeast Asia are reviewed based on recent sampling efforts as well as unreported historical material from southern mainland China, Japan, Taiwan, Thailand and Vietnam. We report 42 new species records for these regions. A total of 20 species new to science are described: S. anhdaoae sp. nov., S. claviseta sp. nov., S. crinigera sp. nov., S. decumbens sp. nov., S. delicata sp. nov., S. densissima sp. nov., S. doydeei sp. nov., S. fellowesi sp. nov., S. intermedia sp. nov., S. jaitrongi sp. nov., S. liuweii sp. nov., S. longidens sp. nov., S. mediocris sp. nov., S. rongi sp. nov., S. scutica sp. nov., S. strummeri sp. nov., S. xenopilus sp. nov., S. yamanei sp. nov., S. zanderi sp. nov. and S. zhenghuii sp. nov. The descriptions of the existing species S. elegantula (Terayama & Kubota, 1989) and S. nathistorisoc Tang et al., 2019 are revised. Strumigenys formosensis Forel, 1912 syn. nov. is synonymized with S. feae Emery 1895 in the light of recently collected specimens. Three species complexes are created within the S. leptothrix-group: elegantula-complex, leptothrix-complex and zanderi-complex, based on differences in dentition. A new species group, S. nathistorisoc-group, is introduced. The key to Strumigenys of East Asia (as Pyramica) by Bolton is partially revised to accommodate species from these species groups that were described since the publication of the key. Finally, the implication of our results to the region and the current limitation of species groups and complexes of the genus is discussed.
 A correction has been published: Tang K.L. & Guénard B. 2024. Further additions to the knowledge of Strumigenys (Formicidae: Myrmicinae) within South East Asia, with the description of 20 species – Corrigendum. European Journal of Taxonomy 917: 194–197. https://doi.org/10.5852/ejt.2024.917.2399

First discovery of the ant genus Eburopone Borowiec, 2016 (Hymenoptera, Formicidae, Dorylinae) in the Oriental realm, with description of a new species from Vietnam.

The doryline ant genus Eburopone Borowiec, 2016 currently contains only one valid species, E.wroughtoni (Forel, 1910) from southern Africa, with a considerable number of undescribed species awaiting formal description in the Afrotropical and Malagasy regions. In the present paper, Eburoponeeasoanasp. nov. is described based on workers and dealate queens from a colony series collected in an evergreen forest on the Dak Lak Plateau of Vietnam (Ea So Nature Reserve, Dak Lak Province). The worker of the new species is morphologically clearly distinguished from E.wroughtoni by the combination of following characteristics: i) frontal line distinct, extending a little beyond mid-length of cranium; ii) anterior (frontoclypeal) margins of torulo-posttorular complex not forming conspicuous lobes protruding over anterior clypeal margin in full-face view; iii) mandibles when closed in full-face view forming only a little space between anterior clypeal margin and mandibles; iv) promesonotal suture faint and inconspicuous; v) abdominal segment III in dorsal view distinctly wider than long, with lateral margins only feebly convex. This represents the first discovery of the genus Eburopone in the Oriental realm, revealing the disjunct distribution of the genus. A partial sequence of the mitochondrial COI gene (658 bp) is provided as a DNA barcode for the new species. A worker-based key to the doryline genera of the Oriental realm is also provided.