Fossil Ants Research Articles

Sensory evidence for complex communication and advanced sociality in early ants.

Advanced social behavior, or eusociality, has been evolutionarily profound, allowing colonies of ants, termites, social wasps, and bees to dominate competitively over solitary species throughout the Cenozoic. Advanced sociality requires not just nestmate cooperation and specialization but refined coordination and communication. Here, we provide independent evidence that 100-million-year-old Cretaceous ants in amber were social, based on chemosensory adaptations. Previous studies inferred fossil ant sociality from individual ants preserved adjacent to others. We analyzed several fossil ants for their antennal sensilla, using original rotation imaging of amber microinclusions, and found an array of antennal sensilla, specifically for alarm pheromone detection and nestmate recognition, sharing distinctive features with extant ants. Although Cretaceous ants were stem groups, the fossilized sensilla confirm hypotheses of their complex sociality.

A fossil "Social Stomach": Micro-CT imaging unearths first fossil record of ant proventriculi and comparative analysis with recent species.

Eusociality is an extreme form of social behavior found in some invertebrates, especially in ants, which allows them to thrive and dominate the environment through their cooperative and organized behavior. Their complex colony structure and social behavior is provided, among other things, by morphological adaptations, such as the unique structure and a huge variety of proventriculi relative to other insect groups. Here, we report the first discovery of proventriculus by X-ray microcomputed tomography (µCT)in the fossil ants †Oecophylla brischkei Mayr, 1868 and †Oecophylla crassinoda Wheeler, 1922. This is a remarkable fossil find, as it opens up new perspectives for research on phylogeny, the evolution of ant sociality and feeding behavior. We present a 3D model of the proventriculus in Oecophylla smaragdina (Fabricius, 1775) and a 3D model of the proventriculus in †Oe. brischkei and compare them. Fossil proventriculi are not fundamentally different in structure from the recent. Apparently, already in the late Eocene, the lifestyle and sociality of ants of the genus Oecophylla were similar to the one we are currently observing.

Deep time extinction of largest insular ant predators and the first fossil Neoponera (Formicidae: Ponerinae) from Miocene age Dominican amber

BackgroundPonerine ants are almost exclusively predatory and comprise many of the largest known ant species. Within this clade, the genus Neoponera is among the most conspicuous Neotropical predators. We describe the first fossil member of this lineage: a worker preserved in Miocene-age Dominican amber from Hispaniola.ResultsNeoponera vejestoria sp. nov. demonstrates a clear case of local extinction—there are no known extant Neoponera species in the Greater Antilles. The species is attributable to an extant and well-defined species group in the genus, which suggests the group is older than previously estimated. Through CT scan reconstruction and linear morphometrics, we reconstruct the morphospace of extant and fossil ants to evaluate the history and evolution of predatory taxa in this island system.ConclusionsThe fossil attests to a shift in insular ecological community structure since the Miocene. The largest predatory taxa have undergone extinction on the island, but their extant relatives persist throughout the Neotropics. Neoponera vejestoria sp. nov. is larger than all other predatory ant workers known from Hispaniola, extant or extinct. Our results empirically demonstrate the loss of a functional niche associated with body size, which is a trait long hypothesized to be related to extinction risk.

Ants (Hymenoptera: Formicidae) from Miocene Ethiopian amber: filling gaps in the geological record of African terrestrial biota

Abstract The Early Miocene (16–23 Mya) amber of Ethiopia constitutes a new source of fossil ants for Africa, where they are otherwise poorly documented. Here we report a diversified assemblage of six subfamilies and at least 19 genera that are still predominantly alive in the Afrotropics today. In this first account, a particular reference is made to the subfamily Dolichoderinae, with the description of two new species: Technomyrmex svojtkai Perrichot & Engel sp. nov. and Ravavy goldmani Boudinot & Perrichot sp. nov. The first is illustrated and described based on synchrotron-radiation microcomputed tomography, and the second represents the first fossil record for the tribe Bothriomyrmecini and Ravavy, a Malagasy and Afrotropical genus that was hitherto monotypic. The ant composition in Ethiopian amber is congruent with the global pattern emerging across ants and showing a Neogene diversification almost exclusively within extant genera.

New fossil ants of the subfamily Myrmicinae (Hymenoptera, Formicidae) from the Upper Oligocene of Enspel (Westerwald Mountains, Rhineland Palatinate, Germany)

New species of the subfamily Myrmicinae are described from the fossil volcanogenic Lake Enspel, Westerwald, Germany. This Fossil-Lagerstatte comprises lake sediments, which essentially consist of intercalated “oilshales” and volcaniclastics. The sediments were dated to be of late Oligocene age. Out of the 287 fossil ants from Enspel examined, 96.5% (n = 277) belong to the formicoid clade (Formicinae, Dolichoderinae, Myrmicinae), and only 3.5% (n = 10) to the poneroid clade (Ponerinae, Agroecomyrmecinae). The high proportion of Myrmicinae (36.6%) indicates that this subfamily was already strongly represented in Central Europe in the late Oligocene. However, it should be noted that the large number of specimens are alate reproductives. The number of workers is low: n = 19, or 6.1% of 312 specimens when 25 isolated wings are included. Ten new species, belonging to the genera Paraphaenogaster, Aphaenogaster, Goniomma and Myrmica are named. Taxonomic questions regarding the separation of the two genera Aphaenogaster and Paraphaenogaster as well as aspects of biogeography, palaeoenvironment and palaeobiology in Enspel are discussed.

Convergent evolution of complex structures for ant–bacterial defensive symbiosis in fungus-farming ants

Evolutionary adaptations for maintaining beneficial microbes are hallmarks of mutualistic evolution. Fungus-farming "attine" ant species have complex cuticular modifications and specialized glands that house and nourish antibiotic-producing Actinobacteria symbionts, which in turn protect their hosts' fungus gardens from pathogens. Here we reconstruct ant-Actinobacteria evolutionary history across the full range of variation within subtribe Attina by combining dated phylogenomic and ultramorphological analyses. Ancestral-state analyses indicate the ant-Actinobacteria symbiosis arose early in attine-ant evolution, a conclusion consistent with direct observations of Actinobacteria on fossil ants in Oligo-Miocene amber. qPCR indicates that the dominant ant-associated Actinobacteria belong to the genus Pseudonocardia Tracing the evolutionary trajectories of Pseudonocardia-maintaining mechanisms across attine ants reveals a continuum of adaptations. In Myrmicocrypta species, which retain many ancestral morphological and behavioral traits, Pseudonocardia occur in specific locations on the legs and antennae, unassociated with any specialized structures. In contrast, specialized cuticular structures, including crypts and tubercles, evolved at least three times in derived attine-ant lineages. Conspicuous caste differences in Pseudonocardia-maintaining structures, in which specialized structures are present in worker ants and queens but reduced or lost in males, are consistent with vertical Pseudonocardia transmission. Although the majority of attine ants are associated with Pseudonocardia, there have been multiple losses of bacterial symbionts and bacteria-maintaining structures in different lineages over evolutionary time. The early origin of ant-Pseudonocardia mutualism and the multiple evolutionary convergences on strikingly similar anatomical adaptations for maintaining bacterial symbionts indicate that Pseudonocardia have played a critical role in the evolution of ant fungiculture.

Giant ants and their shape: revealing relationships in the genus Titanomyrma with geometric morphometrics.

Shape is a natural phenomenon inherent to many different lifeforms. A modern technique to analyse shape is geometric morphometrics (GM), which offers a whole range of methods concerning the pure shape of an object. The results from these methods have provided new insights into biological problems and have become especially useful in the fields of entomology and palaeontology. Despite the conspicuous successes in other hymenopteran groups, GM analysis of wings and fossil wings of Formicidae has been neglected. Here we tested if landmarks defining the wing shape of fossil ants that belong to the genus Titanomyrma are reliable and if this technique is able to expose relationships among different groups of the largest Hymenoptera that ever lived. This study comprises 402 wings from 362 ants that were analysed and assigned with the GM methods linear discriminant function analysis, principal component analysis, canonical variate analysis, and regression. The giant ant genus Titanomyrma and the parataxon Formicium have different representatives that are all very similar but these modern methods were able to distinguish giant ant types even to the level of the sex. Thirty-five giant ant specimens from the Eckfeld Maar were significantly differentiable from a collection of Messel specimens that consisted of 187 Titanomyrma gigantea females and 42 T. gigantea males, and from 74 Titanomyrma simillima females and 21 T. simillima males. Out of the 324 Messel ants, 127 are newly assigned to a species and 223 giant ants are newly assigned to sex with GM analysis. All specimens from Messel fit to the two species. Moreover, shape affinities of these groups and the species Formicium brodiei, Formicium mirabile, and Formicium berryi, which are known only from wings, were investigated. T. gigantea stands out with a possible female relative in one of the Eckfeld specimens whereas the other groups show similar shape patterns that are possibly plesiomorphic. Formicidae are one of the most dominant taxa in the animal kingdom and new methods can aid in investigating their diversity in the present and in deep time. GM of the ant wing delivers significant results and this core of methods is able to enhance the toolset we have now to analyse the complex biology of the ants. It can prove as especially useful in the future when incorporated into better understanding aspects of evolutionary patterns and ant palaeontology.

Primitive ants (Hymenoptera: Sphecomyrminae) in the Campanian (Late Cretaceous) of North Carolina (USA)

A small amber piece containing one nearly complete and four partial winged male fossil ants was collected from a lignite layer at a site along the Neuse River near Goldsboro, North Carolina, USA. Based on the anatomical details, these ants belong to the extinct subfamily Sphecomyrminae. While a formal species description and naming is not the purpose of this paper, similarities are noted to the ant genera Sphecomyrma and Baikurus, and taxonomic identification is made with the latter: Baikurus. This finding confirms the presence of the subfamily Sphecomyrminae in the Campanian stage and adds North Carolina to a short list of worldwide sites where Cretaceous ants have been uncovered. Further, this finding provides added confirmation of the social nature of ants already in the Late Cretaceous with particular reference to swarming behavior, as this piece is the fourth discovery of multiple winged males in amber.

New fossil ants of the subfamily Myrmeciinae (Hymenoptera, Formicidae) from Germany

Two new fossil members of the subfamily Myrmeciinae are described: Archimyrmex wedmannae, sp. nov (Grube Messel, Germany, Middle Eocene) and Prionomyrmex wappleri, sp. nov. (Rott, Germany, Late Oligocene). Members of the genus Archimyrmex were known earlier from Eocene deposits of the United States and Argentina, and members of the genus Prionomyrmex were known from Late Eocene Baltic amber.

Fossil Ponerinae (Hymenoptera: Formicidae) in Early Eocene amber of France

The French Early Eocene (Ypresian, 52–55 million-year-old) amber of Oise contains a rich and well-diversified myrmecofauna, which has remained unstudied until now. A recent survey of these fossil ants revealed 40 different species, among which nine belong to the subfamily Ponerinae. We describe here the two best-preserved morphotypes: a possible ergatoid queen representing the earliest known occurrence of the extant genus Platythyrea Roger, and described as a new species P. dlusskyi sp. n.; and a male morphotype related to the equivocal, paraphyletic genus Pachycondyla Smith, thus described herein but not formally assigned to genus until the male-based taxonomy of Ponerinae is better established. This fauna provides an ecological context to make inferences about the paleoenvironment of northwestern Europe during the PETM and gives new arguments for a radiation of modern ants at that time.

Fossil ants of the genus Gesomyrmex Mayr (Hymenoptera, Formicidae) from the Eocene of Europe and remarks on the evolution of arboreal ant communities

Fossil ants of the genus Gesomyrmex Mayr (Hymenoptera, Formicidae) from the Eocene of Europe and remarks on the evolution of arboreal ant communities

Fossil ants of the genus Gesomyrmex Mayr (Hymenoptera, Formicidae) from the Eocene of Europe and remarks on the evolution of arboreal ant communities

The formicid genus Gesomyrmex is reviewed and several new species are described from the middle Eocene (about 47 Ma) of Grube Messel, Germany, and from the middle Eocene (about 43 Ma) of Eckfeld maar, Germany. The new taxa are Gesomyrmex curiosus n. sp., Gesomyrmex breviceps n. sp., and Gesomyrmex pulcher n. sp. from Messel, and Gesomyrmex flavescens n. sp., and Gesomyrmex germanicus n. sp. from Eckfeld maar. Two previosly described Oligocene species must be excluded from Gesomyrmex. Former G. expectans Théobald, 1937 is transferred to Eoformica expectans (Théobald, 1937) (comb. nov.), and former G. miegi Théobald, 1937 has to be considered as Formicidae incertae sedis (comb. nov.). A key to the living and fossil reproductive female caste (gyne) of the genus Gesomyrmex is provided. Given the fossil records of Gesomyrmex hoernesi Mayr, 1868 from different European amber deposits the presence of this genus in Europe during the Eocene is well established. Both extant and fossil Gesomyrmex species have an arboreal mode of life. The comparison of arboreal ant faunas from Eocene to Recent times shows that their community structure apparently changed considerably during this period. We infer that Gesomyrmex, along with other genera, was most prosperous during the middle Eocene of Europe, and today has a relict distribution in southern Asia.

Primitive New Ants in Cretaceous Amber from Myanmar, New Jersey, and Canada (Hymenoptera: Formicidae)

New information is provided on the oldest fossil ants (Formicidae), including the description of a new species of †Sphecomyrma (†Sphecomyrminae), a new genus of sphecomyrmines, a new genus of apparent myrmeciines, and a new genus of apparent aneuretines. New material from New Jersey amber (Turonian) includes workers of †Sphecomyrma freyi Wilson and Brown preserved together in the same piece of amber, a worker of an unidentifiable †Sphecomyrma species, and a worker of †Brownimecia clavata Grimaldi, Agosti, and Carpenter (†Brownimeciinae). A new species of †Sphecomyrma in New Jersey amber is described and figured from a worker as †S. mesaki, new species. Two worker specimens in Campanian amber from Canada are described, one of which is described as †Cananeuretus occidentalis, new genus and species, and is tentatively placed in Aneuretinae. From Burmese amber (Albian-Cenomanian) are the oldest, definitive ants, along with ones in amber from Charente-Maritime of France (approximately contemporaneous in age). A new genus and species, allied to †Sphecomyrma, is described from these deposits as †Sphecomyrmodes orientalis, along with a remarkable new “poneroid”, †Myanmyrma gracilis, new genus and species (Myrmeciinae?). A key to the species of †Sphecomyrma is provided, the classification of ants summarized, and the Cretaceous records of Formicidae briefly outlined.

A formicine in New Jersey cretaceous amber (Hymenoptera: formicidae) and early evolution of the ants.

A worker ant preserved with microscopic detail has been discovered in Turonian-aged New Jersey amber [ca. 92 mega-annum (Ma)]. The apex of the gaster has an acidopore and, thus, allows definitive assignment of the fossil to the large extant subfamily Formicinae, members of which use a defensive spray of formic acid. This specimen is the only Cretaceous record of the subfamily, and only two other fossil ants are known from the Cretaceous that unequivocally belong to an extant subfamily (Brownimecia and Canapone of the Ponerinae, in New Jersey and Canadian amber, respectively). In lieu of a cladogram of formicine genera, generalized morphology of this fossil suggests a basal position in the subfamily. Formicinae and Ponerinae in the mid Cretaceous indicate divergence of basal lineages of ants near the Albian (ca. 105-110 Ma) when they presumably diverged from the Sphecomyrminae. Sphecomyrmines are the plesiomorphic sister group to all other ants, or they are a paraphyletic stem group ancestral to all other ants-they apparently became extinct in the Late Cretaceous. Ant abundance in major deposits of Cretaceous and Tertiary insects indicates that they did not become common and presumably dominant in terrestrial ecosystems until the Eocene (ca. 45 Ma). It is at this time that modern genera that form very large colonies (at least 10,000 individuals) first appear. During the Cretaceous, eusocial termites, bees, and vespid wasps also first appear-they show a similar pattern of diversification and proliferation in the Tertiary. The Cretaceous ants have further implications for interpreting distributions of modern ants.

Oldest known ant fossils discovered

Here we report fossil ants, including a new genus of Ponerinae, about 50 million years (Myr) older than the previous oldest specimens. These discoveries in amber from the Turonian stage (92 Myr ago) of New Jersey in the United States have important implications for estimates dating the origin of ants, and extend the age of an extant ant subfamily back about 50 Myr.

The fossil ants of North America.

The fossil ants of North America.

Tertiary Fossil Ants in the Isle of Wight

IN a paper published in NATURE for August 22, p. 399, by Prof. C. Emery, on “The Origin of European and North American Ants,” the author states that “the Sicilian amber of Miocene age contains genera which belong to the actual Indian and Australian fauna, while the Baltic amber contains the genera Formica, Lasius, and Myrmica.” In the Bembridge limestone in the Isle of Wight, of Eocene age, the same as the Baltic amber, the following genera occur: Formica, Myrmica, and Camponotus, and some others not yet described. In my collection there are a large number of these Hymenoptera, generally well preserved, and seem to be more numerous than any of the other insects from the same beds. It is only of late years that any number of insects have been met with in the British tertiaries, and it is well to record the two genera referred to Formica and Myrmica, being found both in the Baltic amber and Bembridge limestone. Among the numerous fossil insects in my possession from the Lias, no trace of any ants has been observed, and it seems that they did not come into existence until the later Tertiary epoch.