Gerontoformica

†Gerontoformica Temporal range: 100–98 Ma K Pa Eo Ol Mi Pl Late Albian to Early Cenomanian, Cretaceous to Early Cenomanian, Late Cretaceous
Gerontoformica cretacica
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Sphecomyrminae
Tribe:	Sphecomyrmini
Genus:	†Gerontoformica Nel & Perrault, 2004
Type species
Gerontoformica cretacica
Diversity
13 fossil species (Species Checklist)
Synonyms
†Sphecomyrmodes Engel & Grimaldi, 2005

Photo Gallery

• 
• 
• 
• 
• 

• 

  Chaul (2023), Fig. 2. Masticatory margin of mandible in Gerontoformica and Zigrasimecia. A, Gerontoformica sp. (ANTWEB1032629); B, Z. ferox (ANTWEB1008126); C, Z. chuyangsui (ANTWEB1032660); D, Z. tonsora (ANTWEB11008098). Black triangles indicate incision between apical and basal teeth (or basal lamella). Image of Z. tonsora by Philip Barden and image of Z. ferox by Vincent Perrichot, courtesy of Antweb.org.
• 

  Chaul (2023), Fig. 3. Comparison between Gerontoformica and Zigrasimecia cephalic and mandibular morphology (see genus diagnosis above for detailed explanation). A and C, schematic drawing of full-face view of Gerontoformica and Zigrasimecia, respectively. B and D, lateral view of anterior head of Gerontoformica (ANTWEB1032649) and Zigrasimecia (ANTWEB1032623), respectively. Abbreviations: cl, clypeus; cllb, clypeal lobe; dsm, dorsal surface of mandible; fcr, frontal carina; plstf, pleurostomal fossa; tl, torulus. In D, white line indicates plane (as seen laterally) of labrum; gray line is the plane (as seen laterally) of the apical half surface of the mandible; and black line shows the strong mandible curvature.
• 

  Chaul (2023), Fig. 4. Ventral view of the head of Gerontoformica (A) and Zigrasimecia (B). Abbreviations: cllb, clypeal lobe; dsm, dorsal surface of mandible; lb, labrum; oc, occipital carina; pgs, postgenal suture; plstf, pleurostomal fossa.
• 

  Chaul (2023), Fig. 5. Types of mesosoma in fossil and extant ants. A, Gerontoformica; B, Protozigrasimecia; C, Zigrasimecia; D, Brownimecia; E, Brachyponera and F, Discothyrea. Among extant ants, Discothyrea presents a degree of mesosomal compaction similar to that of Zigrasimecia. Abbreviations: Lmspl, lower mesopleuron; Lmtpl, lower metapleuron; mgo, metapleural gland opening; Msn, mesonotum; Mspl, mesopleuron; Mssct, mesoscutum; Mssctl, mesoscutellum; Mtn, metanotum; Ppd, propodeum; Prn, pronotum; Prpl, propleuron, sp, spiracle; Umspl, upper mesopleuron; Umtpl, upper metapleuron.

Distribution

This taxon is known from Burmese amber, Kachin State, Myanmar (Early Cenomanian, Late Cretaceous) and Charentese amber, Aquitaine Basin, France (Late Albian to Early Cenomanian, Cretaceous).

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

• †GERONTOFORMICA [†Sphecomyrminae: †Sphecomyrmini]]
  • †Gerontoformica Nel & Perrault, in Nel, Perrault, Perrichot & Néraudeau, 2004: 24. Type-species: †Gerontoformica cretacica, by original designation.
• Taxonomic history
  • †Gerontoformica incertae sedis in Formicidae: Nel, et al. 2004: 24.
  • †Gerontoformica in †Sphecomyrminae: Perrichot, 2014: 168 (in text).
  • †Gerontoformica in †Sphecomyrminae, †Sphecomyrmini: Borysenko, 2017: 15
  • †Gerontoformica as senior synonym of †Sphecomyrmodes: Barden & Grimaldi, 2016: 4, and in supplemental information (not paginated).
• †SPHECOMYRMODES [junior synonym of †Gerontoformica]
  • †Sphecomyrmodes Engel & Grimaldi, 2005: 5. Type-species: †Sphecomyrmodes orientalis, by original designation.
• Taxonomic history
  • †Sphecomyrmodes in †Sphecomyrminae: Engel & Grimaldi, 2005: 5.
  • †Sphecomyrmodes as genus: Barden & Grimaldi, 2014: 18.
  • †Sphecomyrmodes as junior synonym of †Gerontoformica: Barden & Grimaldi, 2016: 4, and in supplemental information (not paginated).
  • †Sphecomyrmodes references: Barden & Grimaldi, 2014: 18 (diagnosis, all species key).

References

• Barden, P. & Grimaldi, D.A. 2016. Adaptive radiation in socially advanced stem-group ants from the Cretaceous. Current Biology 26: 515-521 (doi:10.1016/j.cub.2015.12.060).
• Barden, P. 2017. Fossil ants (Hymenoptera: Formicidae): ancient diversity and the rise of modern lineages. Myrmecological News 24: 1-30.
• Barden, P., Engel, M.S. 2020. Fossil social insects. Encyclopedia of Social Insects, Springer, Cham (doi:10.1007/978-3-319-90306-4_45-1).
• Borysenko, L.H. 2017. Description of a new genus of primitive ants from Canadian amber, with the study of relationships between stem- and crown-group ants (Hymenoptera: Formicidae). Insecta Mundi 570: 1–57.
• Boudinot, B.E., Perrichot, V., Chaul, J.C.M. 2020. †Camelosphecia gen. nov., lost ant-wasp intermediates from the mid-Cretaceous (Hymenoptera, Formicoidea). ZooKeys 1005, 21–55 (doi:10.3897/zookeys.1005.57629).
• Boudinot, B.E., Richter, A., Katzke, J., Chaul, J.C.M., Keller, R.A., Economo, E.P., Beutel, R.G., Yamamoto, S. 2022. Evidence for the evolution of eusociality in stem ants and a systematic revision of †Gerontoformica (Hymenoptera: Formicidae). Zoological Journal of the Linnean Society XX:1-35 (doi:10.1093/zoolinnean/zlab097/6523228).
• Cantone, S., Von Zuben, C.J. 2019. The hindwings of ants: A phylogenetic analysis. Psyche: A Journal of Entomology 2019, 1–11 (doi:10.1155/2019/7929717).
• Nel, A.; Perrault, G. 2004. [Untitled. Genus Gerontoformica Nel and Perrault n. gen. Type species: Gerontoformica cretacica Nel and Perrault n. sp.]. Pp. 24-26 in: Nel, A.; Perrault, G.; Perrichot, V.; Néraudeau, D. The oldest ant in the Lower Cretaceous (page 24, Gerontoformica as genus; incertae sedis in Formicidae)
• Sosiak, C., Cockx, P., Suarez, P.A., McKellar, R., Barden, P. 2024. Prolonged faunal turnover in earliest ants revealed by North American Cretaceous amber. Current Biology (doi:10.1016/j.cub.2024.02.058).