|Peruvian worker of T. tatusia; photograph by Erin Prado|
Aside from Tatuidris, the armadillo ants include only the extinct genera Agroecomyrmex (from Baltic amber; Wheeler, 1914) and Eulithomyrmex (from the Coloradoan Florissant Formation; Carpenter, 1935): both date to the Paleogene Period (the latter about 10 million years younger than the former; Ritzkowski, 1997; Foos & Hannibal, 1999). Their assignment to the Myrmicinae (one of the most speciose single subfamilies within the Formicidae) was made on the basis of morphological similarities to members of the tribe Phalacromyrmecini, and, to a lesser extent, Dacetini (Brown & Kempf, 1968; Brown, 1977; Bolton, 1984): these common characteristics include an expanded facial vertex and deepened scrobes* (the extension of which all the way back to the eyes is another distinctive quality of Tatuidris; Baroni Urbani & de Andrade, 2007). Right from the description of the first living agroecomyrmecine (T. tatusia) these traits were suspected of being only dubiously indicative of kinship (Brown & Kempf, 1968; Bolton, 1984): speciousness affirmed by the elevation of the Agroecomyrmecini to subfamily rank (Bolton, 2003), although the first fully cladistic analysis of T. tatusia affirmed its relation to the Dacetini and inclusion within the Myrmicinae (Baroni Urbani & de Andrade, 2007).
|Ecuadorian bullet ant (Paraponera clavata) photographed by Alex Wild (who else?)|
|Variation in pilosity patterns within T. tatusia (Donoso, 2012)|
Almost nothing is known of the habits of T. tatusia, given that until recently none had been observed in life: but its weirdly elongated stinger and thickly interlocking setae on the inner margins of the mandibles—not to mention intramandibular glands clustered in a manner unknown in other ants (Billen & Delsinne, 2013)—have encouraged speculation on the ant's presumably unorthodox biology. In further tantalization, the discovery of the first live colony (containing erstwhile-unknown drones and queens) revealed only that armadillo ants have a diet that does not include the following likely items:
" ... live and dead termites, millipedes, mites, various insect parts, sugar water, tuna, biscuits, live and dead fruit flies (Drosophila), live springtails, live myriapods (Chilopoda and Diplopoda) [centipedes and millipedes], live and dead Diplura, small live spiders, small live pseudoscorpions, one small snail, uncooked hen egg ... ant larvae (Gnamptogenys sp.), and live ant workers (Cyphomyrmex sp., Brachymyrmex sp.)." (Donoso, 2012)Hence, we can only assume that T. tatudris is a most specialized predator. Of what, precisely, remains to be seen whenever science captures its next glimpse of armadillo ants.
*Cephalic slots into which antennae can be retracted.
Baroni Urbani, C. and de Andrade, M. L. (2007). The ant tribe Dacetini: limits and constituent genera, with descriptions of new species. Annali del Museo Civico di Storia Naturale "G. Doria", 99, 1-191.
Billen, J. and Delsinne, T. (2013). A novel intramandibular gland in the ant Tatuidris tatusia (Hymenoptera: Formicidae). Myrmecological News, 19, 61-64. Retrieved 5/8/14 from http://bio.kuleuven.be/ento/pdfs/billen_delsinne_myrmnews_2013.pdf
Bolton, B. (1984). Diagnosis and relationships of the myrmicine ant Ishakidris gen. n. (Hymenoptera: Formicidae). Systematic Entomology, 9, 373-382.
Bolton, B. (2003). Synopsis and classification of Formicidae. Memoirs of the American Entomological Institute, 71, 1-370.
Brady, S. G.; Schultz, T. R.; Fisher, B. L.; and Ward, P. S. (2006). Evaluating alternative hypotheses for the early evolution and diversification of ants. Proceedings of the National Academy of Sciences of the United States of America, 103(48), 18172–18177.
Brown, W. L. (1977). An aberrant new genus of myrmicine ant from Madagascar. Psyche, 84, 218-224.
Brown, W. L. and Kempf, W. W. (1968). Tatuidris, a remarkable new genus of Formicidae (Hymenoptera). Psyche, 74, 183-190.
Carpenter, F. M. (1930). The fossil ants of North America [electronic version]. Bulletin of the Museum of Comparative Zoology, 70(1), 1-66. Retrieved 5/7/14 from http://gap.entclub.org/taxonomists/Carpenter/1930.pdf
Carpenter, F. M. (1935). A new name for Lithomyrmex Carp. (Hymenoptera) [electronic version]. Psyche, 42(2), 91. Retrieved 5/6/14 from http://www.hindawi.com/journals/psyche/1935/068604/abs/
Donoso, D. A. (2012). Additions to the taxonomy of the armadillo ants (Hymenoptera, Formcidae, Tatuidris) [electronic version]. Zootaxa, 3503, 61-81. Retrieved 5/8/14 from http://mapress.com/zootaxa/2012/f/zt03503p081.pdf
Foos, A. and Hannibal, J. (1999). Geology of Florissant Fossil Beds National Monument. Retrieved 5/5/14 from http://www2.nature.nps.gov/geology/education/foos/flfo.pdf
Hölldobler, B. and Wilson, E. O. (1990). The Ants. The Belknap University Press of Harvard University Press: Cambridge.
Lacau, S.; Groc, S.; Dejean, A.; de Oliveira, M. L.; and Delabie, J. H. C. (2012). Tatuidris kapasi sp. nov.: a new armadillo ant from French Guiana (Formicidae: Agroecomyrmecinae). Psyche, 2012(2012), 926089, 1-7. Retrieved 5/8/13 from http://www.hindawi.com/journals/psyche/2012/926089/
Rabeling, C.; Brown, J. M.; and Verhaagh, M. (2008). Newly discovered sister lineage sheds light on early ant evolution. Proceedings of the National Academy of Sciences, USA; 105, 14913-14917.
Ritzkowski, S. (1997). K-Ar-Altersbestimmungen der bernsteinführenden Sedimente des Samlandes (Paläogen, Bezirk Kaliningrad). Metalla, Bochum; 66, 19-23.
Ward, P. S. (2009). Phylogeny, classification, and species-level taxonomy of ants (Hymenoptera: Formicidae) [electronic version]. Zootaxa, 1669, 549-563. Retrieved 5/8/14 from http://wardlab.files.wordpress.com/2012/01/ward_2007c_zoootaxa.pdf
Wheeler, W. M. (1914). The ants of the Baltic amber. Schriften der Physikalisch-Okonomischen Gesellschaft, 55(4), 56-59.
Yee, D. (2004). The Ants: Bert Hölldobler + Edward O. Wilson. Retrieved 5/7/14 from http://dannyreviews.com/h/Ants.html