Trachymyrmex septentrionalis

In suitable habitats, typically semi-open vegetation types occurring on sandy soil, this ant can be locally abundant. In such areas, the conspicuous crescent-shaped soil mound found around their ground nest entrances occur in high densities.

Identification
Trachymyrmex septentrionalis is disturbingly similar to the allopatric Trachymyrmex carinatus, but separable by the characters given in the key and by their non-overlapping distributions; carinatus occurs only in the desert southwest, septentrionalis occurs in Texas and the states north and east of there. Molecular evidence suggests the similarity is convergent. It is likely that collections identified in the literature as T. septentrionalis from Durango, Mexico may actually represent T. carinatus (Rojas-Fernandez 1994). Solely considering the publication date, Oecodoma virginiana Buckley (1867) would have seniority over McCook’s (1881) Atta septentrionalis. But since Buckley’s species description is insufficiently detailed to either recognize T. septentrionalis or distinguish between septentrionalis and its congeners, Wheeler (1902) proposed Oocodoma virginiana Buckley to be a junior synonym of Atta septentrionalis McCook. We agree with Wheeler and continue using the species name septentrionalis. Unfortunately, the locality of both types is unknown and we could not examine them. (Rabeling et al. 2007)

Distribution
Trachymyrmex septentrionalis has the most extensive distribution of all attine ants in the US. It has been collected from Texas to Florida and as far north as central Illinois, southern Ohio and Long Island, New York. (Rabeling et al. 2007)

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Mexico.

Habitat
Like most fungus-growing ants, the distribution of T. septentrionalis is locally patchy. In part, this may be a consequence of the distribution of suitable soils. In the northern part of its range, T. septentrionalis occurs exclusively on pure sand soils in open habitats and open woodlands of the Pine Barrens. In the southern US, T. septentrionalis is abundant in a wide variety of similar oak and pine dominated habitat types, all characterized by very sandy soils and light (if any) shade. It has also occasionally been found nesting in sandy clay soils in well-developed forests with considerable shade, particularly in the southern part of its range. (Rabeling et al. 2007)

Biology
From Rabeling et al. (2007): During periods of high nest excavation activity in spring and fall, the crescent shaped mounds of T. septentrionalis are distinctive and conspicuous (Tschinkel & Bhatkar 1974). Older colonies may have several chambers, connected by one to few tunnels and inhabit a few hundred individuals (Weber 1972). As the northernmost distributed species of Trachymyrmex, colonies of T. septentrionalis hibernate during the winter and the fungus garden assumes a dormant condition. The length of hibernation varies considerably with respect to latitude. The northernmost populations in New York and New Jersey have short active periods from early May to September, whereas Florida populations remain active during the winter, as long as temperatures exceed 18oC (Weber 1972). The army ant Neivamyrmex nigrescens and the ectatommine ant Gnamptogenys hartmani are known to raid colonies of T. septentrionalis (Cole 1939).

Nomenclature

 * virginiana. Oecodoma virginiana Buckley, 1867: 346 (w.) U.S.A. Junior synonym of septentrionalis: Wheeler, W.M. 1902f: 29.
 *  septentrionalis. Atta septentrionalis McCook, 1881a: 362 (w.) U.S.A. Wheeler, W.M. 1907c: 707 (q.m.); Wheeler, G.C. 1949: 673 (l.). Combination in Atta (Trachymyrmex): Forel, 1912e: 182; in Trachymyrmex: Gallardo, 1916b: 242. Senior synonym of virginiana: Wheeler, W.M. 1902f: 29; of vertebrata: Creighton, 1950a: 323; of obscurior, seminole: Weber, 1958b: 53. See also: Wheeler, W.M. 1911g: 246; Smith, D.R. 1979: 1411; Petralia & Vinson, 1980: 383; Rabeling, Cover, et al. 2007: 17.
 * obscurior. Atta (Trachymyrmex) septentrionalis var. obscurior Wheeler, W.M. 1907c: 709 (w.q.) U.S.A. Wheeler, W.M. 1911g: 246 (q.). Combination in Trachymyrmex: Creighton, 1950a: 324. Subspecies of septentrionalis: Wheeler, W.M. 1911g: 247. Material of the unavailable names crystallina, irrorata referred here by Creighton, 1950a: 324. Junior synonym of septentrionalis: Weber, 1958b: 53.
 * vertebrata. Atta (Trachymyrmex) septentrionalis var. vertebrata Wheeler, W.M. 1911g: 246 (w.q.) U.S.A. Junior synonym of septentrionalis: Creighton, 1950a: 323.
 * seminole. Trachymyrmex septentrionalis subsp. seminole Creighton, 1950a: 324 (w.q.m.) U.S.A. [First available use of Atta (Trachymyrmex) septentrionalis subsp. obscurior var. seminole Wheeler, W.M. 1911g: 247; unavailable name.] Junior synonym of septentrionalis: Weber, 1958b: 53.

Worker
Diagnosis from Rabeling et al. (2007): HL 0.84–0.96, HW 0.88–1.0, CI 104–105, SL 0.84–0.96, SI 96, ML 1.12–1.32. A relatively small (HL 0.84–0.96, HW 0.88–1.0), conspicuously tuberculate species with normally proportioned legs and antennal scapes (SI 96). Head slightly broader than long (CI 104–105), sides subparallel behind the eyes, gradually tapering anteriorly between the eyes and the mandibular insertion. Posterior margin moderately concave. Preocular carinae long, traversing 2/3 to 3⁄4 of the distance between the eye and the frontal carina but not nearly touching the frontal carinae. In full-face view, frontal lobes rounded or subtriangular, usually somewhat asymmetric, with the anterior side longer than the posterior. Anterolateral promesonotal teeth well- developed, thin, sharply pointed in dorsal view, projecting somewhat upward as well as horizontally. Anterior median pronotal tubercles upright, toothlike in posterior view. Propodeal teeth usually longer than the distance separating their bases, often spinelike, pointed. Posterior margin of head, mesonotal dorsum, dorsal surfaces of petiole, postpetiole and gaster conspicuously tuberculate, tuberculi largest particularly on posterior corners of head and on the first gastric tergite. Color brownish yellow to medium reddish-brown.

Queen
Diagnosis from Rabeling et al. (2007): HL 1.05–1.2, HW 1.1–1.25, CI 104–107, SL 1.05–1.15, SI 96–100, ML 1.55–1.85. As in worker diagnosis, but with caste-specific morphology the mesosoma related to wing-bearing. Dorsolateral pronotal teeth variable in size, but sharply triangulate in dorsal view, often blunt in anterior view. Ventrolateral pronotal teeth variable, but generally lobelike. Mesoscutum coarsely, longitudinally rugulose, finely tuberculate, tuberculi with short, sharply recurved hairs. First gastric tergite with numerous small tubercles bearing short, recurved, decumbent, recurved setae.

Male
Diagnosis from Rabeling et al. (2007): HL 0.75, HW 0.8–0.9, CI 100–107, SL 0.9–1.1, SI 113–122, ML 1.5–1.85. In frontal view, posterior corners of the head angulate, angles formed by short, tuberculate ridges best seen in dorsal view; ocelli small and inconspicuous. Dorsoventral pronotal teeth, short, sharp, triangulate in dorsal view; ventrolateral teeth short, triangular or lobelike. Sculpture of mesoscutum coarse, irregular, rugulose, sometimes weakly longitudinal. Tuberculi generally absent (miniscule, if present) on first gastric tergite.

Etymology
McCook (1881) described the worker of T. septentrionalis based on material collected from Island Heights in the New Jersey Pine Barrens. The species name septentrionalis refers to the seven plowing oxen, the brightest stars of the Great Bear constellation, which dominate the skies of the northern hemisphere. Thus, septentrionalis loosely translates to “northern” in the context of North American fungus-growing ants. (Rabeling et al. 2007).

References based on Global Ant Biodiversity Informatics

 * Annotated Ant Species List Ordway-Swisher Biological Station. Downloaded at http://ordway-swisher.ufl.edu/species/os-hymenoptera.htm on 5th Oct 2010.
 * Atchison R. A., J. Hulcr, and A. Lucky. 2018. Managed fire frequency significantly influences the litter arthropod community in longleaf pine flatwoods. Environmental Entomology 20(10): 1-11.
 * Callcott A. M. A., D. H. oi, H. L. Collins, D. F. Williams, and T. C. Lockley. 2000. Seasonal Studies of an Isolated Red Imported Fire Ant (Hymenoptera: Formicidae) Population in Eastern Tennessee. Environmental Entomology, 29(4): 788-794.
 * Carroll T. M. 2011. The ants of Indiana (Hymenoptera: Formicidae). Master's Thesis Purdue university, 385 pages.
 * Cole A. C., Jr. 1953. A checklist of the ants (Hymenoptera: Formicidae) of the Great Smoky Mountains National Park, Tennessee. Journal of the Tennessee Academy of Science 28: 34-35.
 * Coovert G. A. 2005. The Ants of Ohio (Hymenoptera: Formicidae). Ohio Biological Survey, Inc. 15(2): 1-207.
 * Coovert, G.A. 2005. The Ants of Ohio (Hymenoptera: Formicidae) Ohio Biological Survey Bulletin New Series Volume 15(2):1-196
 * Dash S. T. and L. M. Hooper-Bui. 2008. Species diversity of ants (Hymenoptera: Formicidae) in Louisiana. Conservation Biology and Biodiversity. 101: 1056-1066
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Davis W. T., and J. Bequaert. 1922. An annoted list of the ants of Staten Island and Long Island, N. Y. Bulletin of the Brooklyn Entomological Society 17(1): 1-25.
 * Dean D. A., and S. R. Dean. 2018. A survey of the ant fauna and seasonal alate nuptial flights at two locations in South-Central Texas. Southwestern Entomologist 43(3): 639-647.
 * Dennis C. A. 1938. The distribution of ant species in Tennessee with reference to ecological factors. Annals of the Entomological Society of America 31: 267-308.
 * Deyrup M., C. Johnson, G. C. Wheeler, J. Wheeler. 1989. A preliminary list of the ants of Florida. Florida Entomologist 72: 91-101
 * Deyrup M., L. Deyrup, and J. Carrel. 2013. Ant Species in the Diet of a Florida Population of Eastern Narrow-Mouthed Toads, Gastrophryne carolinensis. Southeastern Naturalist 12(2): 367-378.
 * Deyrup, M. and J. Trager. 1986. Ants of the Archbold Biological Station, Highlands County, Florida (Hymenoptera: Formicidae). Florida Entomologist 69(1):206-228
 * DuBois M. B. 1981. New records of ants in Kansas, III. State Biological Survey of Kansas. Technical Publications 10: 32-44
 * DuBois M. B. 1985. Distribution of ants in Kansas: subfamilies Ponerinae, Ecitoninae, and Myrmicinae (Hymenoptera: Formicidae). Sociobiology 11: 153-1360
 * Dubois, M.B. and W.E. Laberge. 1988. An Annotated list of the ants of Illionois. pages 133-156 in Advances in Myrmecology, J. Trager
 * Fernandes, P.R. XXXX. Los hormigas del suelo en Mexico: Diversidad, distribucion e importancia (Hymenoptera: Formicidae).
 * Forel A. 1912. Formicides néotropiques. Part II. 3me sous-famille Myrmicinae Lep. (Attini, Dacetii, Cryptocerini). Mémoires de la Société Entomologique de Belgique. 19: 179-209.
 * Forster J.A. 2005. The Ants (hymenoptera: Formicidae) of Alabama. Master of Science, Auburn University. 242 pages.
 * Frye J. A., T. Frye, and T. W. Suman. 2014. The ant fauna of inland sand dune communities in Worcester County, Maryland. Northeastern Naturalist, 21(3): 446-471.
 * General D. M., and L. C. Thompson. 2011. New Distributional Records of Ants in Arkansas for 2009 and 2010 with Comments on Previous Records. Journal of the Arkansas Academy of Science 65: 166-168.
 * General D., and L. Thompson. 2008. New distributional records of ants in Arkansas. Journal of the Arkansas Academy of Science 62: 148-150.
 * General D.M. & Thompson L.C. 2008. New Distributional Records of Ants in Arkansas for 2008. Journal of the Arkansas Academy of Science. 63: 182-184
 * Graham, J.H., A.J. Krzysik, D.A. Kovacic, J.J. Duda, D.C. Freeman, J.M. Emlen, J.C. Zak, W.R. Long, M.P. Wallace, C. Chamberlin-Graham, J.P. Nutter and H.E. Balbach. 2008. Ant Community Composition across a Gradient of Disturbed Military Landscapes at Fort Benning, Georgia. Southeastern Naturalist 7(3):429-448
 * Hill J.G. & Brown R. L. 2010. The Ant (Hymenoptera: Formicidae) Fauna of Black Belt Prairie Remnants in Alabama and Mississippi. Southeastern Naturalist. 9: 73-84
 * Hill, J.G. 2006. Ants collected at Okatibbee Lake, Lauderdale County, Mississippi
 * Ipser R. M. 2004. Native and exotic ants (Hymenoptera: Formicidae) of Georgia: Ecological Relationships with implications for development of biologically-based management strategies. Doctor of Philosophy thesis, University of Georgia. 165 pages.
 * Ivanov K. 2016. Checklilst of the ants (Hymenoptera: Formicidae) of Virginia v. 6. April 6 2016 version.
 * Ivanov K. 2019. The ants of Ohio (Hymenoptera, Formicidae): an updated checklist. Journal of Hymenoptera Research 70: 65–87.
 * Ivanov K., L. Hightower, S. T. Dash, and J. B. Keiper. 2019. 150 years in the making: first comprehensive list of the ants (Hymenoptera: Formicidae) of Virginia, USA. Zootaxa 4554 (2): 532–560.
 * Johnson C. 1986. A north Florida ant fauna (Hymenoptera: Formicidae). Insecta Mundi 1: 243-246
 * Lynch J. F. 1988. An annotated checklist and key to the species of ants (Hymenoptera: Formicidae) of the Chesapeake Bay region. The Maryland Naturalist 31: 61-106
 * MacGown J. A. 2015. Report on the ants collected on Spring Island, Beaufort County, South Carolina. A report submitted to Spring Island Nature Preserve, May 2015. Mississippi Entomological Museum Report #2015-01. 8 pp
 * MacGown J. A., J. G. Hill, R. L. Brown, T. L. Schiefer, J. G. Lewis. 2012. Ant diversity at Noxubee National Wildlife Refuge in Oktibbeha, Noxubee, and Winston Counties, Mississippi. Mississippi Agricultural and Forestry Experiment Station Bulletin 1197: 1-30
 * MacGown J. A., J. G. Hill, and M. Deyrup. 2009. Ants (Hymenoptera: Formicidae) of the Little Ohoopee River Dunes, Emanuel County, Georgia. J. Entomol. Sci. 44(3): 193-197.
 * MacGown J. A., J. G. Hill, and R. L. Brown. 2010.  Native and exotic ant in Mississippi state parks.  Proceedings:  Imported Fire Ant Conference, Charleston, South Carolina, March 24-26, 2008: 74-80.
 * MacGown J. A., T. L. Schiefer, and M. G. Branstetter. 2015. First record of the genus Leptanilloides (Hymenoptera: Formicidae: Dorylinae) from the United States. Zootaxa 4006 (2): 392–400.
 * MacGown J. A., and R. L. Brown. 2006. Survey of the ants (Hymenoptera: Formicidae) of the Tombigbee National Forest in Mississippi. Journal of the Kansas Entomological Society 79(4):325-340.
 * MacGown J. A., and R. Whitehouse. 2015. A preliminary report of the ants of West Ship Island. A report submitted to the Gulf Islands National Seashore. Mississippi Entomological Museum Report #2015-02. 9 pp.
 * MacGown, J. and J.G. Hill. Ants collected at Palestinean Gardens, George County Mississippi.
 * MacGown, J.A and J.A. Forster. 2005. A preliminary list of the ants (Hymenoptera: Formicidae) of Alabama, U.S.A. Entomological News 116(2):61-74
 * MacGown, J.A. and JV.G. Hill. Ants of the Great Smoky Mountains National Park (Tennessee and North Carolina).
 * MacGown, J.A. and R.L. Brown. 2006. Observations on the High Diversity of Native Ant Species Coexisting with Imported Fire Ants at a Microspatial Scale in Mississippi. Southeastern Naturalist 5(4):573-586
 * MacGown, J.A. and R.L. Brown. 2006. Survey of the ants (Hymenoptera: Formicidae) of the Tombigbee National Forest in Mississippi. Journal of the Kansas Entomological Society 79(4):325-340.
 * MacGown, J.A. and T. Lockley. Ants of Horn Island, Jackson County, Mississippi
 * MacGown, J.A., J.G. Hill, R.L. Brown and T.L. 2009. Ant Diversity at Noxubee National Wildlife Refuge in Oktibbeha, Noxubee, and Winston Counties, Mississippi Report #2009-01. Schiefer. 2009.
 * MacKay W. P., and S. B. Vinson. 1988. Rediscovery of the ant Gnamptogenys hartmani (Hymenoptera: Formicidae) in eastern Texas. Proceedings of the Entomological Society of Washington 91: 127.
 * Macgown J. A., S. Y. Wang, J. G. Hill, and R. J. Whitehouse. 2017. A List of Ants (Hymenoptera: Formicidae) Collected During the 2017 William H. Cross Expedition to the Ouachita Mountains of Arkansas with New State Records. Transactions of the American Entomological Society, 143(4): 735-740.
 * Martelli, M.G., M.M. Ward and Ann M. Fraser. 2004. Ant Diversity Sampling on the Southern Cumberland Plateau: A Comparison of Litter Sifting and Pitfall Trapping. Southeastern Naturalist 3(1): 113-126
 * Moody J. V., and O. F. Francke. 1982. The Ants (Hymenoptera, Formicidae) of Western Texas Part 1: Subfamily Myrmicinae. Graduate Studies Texas Tech University 27: 80 pp.
 * Moreau C. S., M. A. Deyrup, and L. R. David Jr. 2014. Ants of the Florida Keys: Species Accounts, Biogeography, and Conservation (Hymenoptera: Formicidae). J. Insect Sci. 14(295): DOI: 10.1093/jisesa/ieu157
 * Murakami T., A. Fujiwara,and M. C. Yoshida. 1999. Cytogenetics of ten ant species of the tribe Attini (Hymenoptera, Formicidae) in Barro Colorado Island, Panama. Chromosome Science 2(3): 135-139.
 * O'Keefe S. T., J. L. Cook, T. Dudek, D. F. Wunneburger, M. D. Guzman, R. N. Coulson, and S. B. Vinson. 2000. The Distribution of Texas Ants. The Southwestern Entomologist 22: 1-92.
 * Rabeling C., S. P. Cover, R. A. Johnson, and U. G. Mueller. 2007. A review of the North American species of the fungus-gardening ant genus Trachymyrmex (Hymenoptera: Formicidae). Zootaxa 1664: 1-53
 * Roeder K. A., and D. V. Roeder. 2016. A checklist and assemblage comparison of ants (Hymenoptera: Formicidae) from the Wichita Mountains Wildlife Refuge in Oklahoma. Check List 12(4): 1935.
 * Ross H. H., G. L. Rotramel, and W. E. LeBerge. 1971. A synopsis of common and economic Illinois antsm with keys to the genera (Hymenoptera, Formicidae). Illinois Nat. history Surv. Biol. Notes 71: 1-22.
 * Seal J. N., L. Brown, C. Ontiveros, J. Thiebaud, and U. G. Mueller. 2015. Gone to Texas: phylogeography of two Trachymyrmex (Hymenoptera: Formicidae) species along the southeastern coastal plain of North America. Biological Journal of the Linnean Society 114: 689–698.
 * Smith M. R. 1934. A list of the ants of South Carolina. Journal of the New York Entomological Society 42: 353-361.
 * Smith M. R. 1935. A list of the ants of Oklahoma (Hymen.: Formicidae). Entomological News 46: 235-241.
 * Smith M. R. 1936. A list of the ants of Texas. Journal of the New York Entomological Society 44: 155-170.
 * Solomon S. E., C. Rabeling, J. Sosa-Calvo, C. Lopes, A. Rodrigues, H. L. Vasconcelos, M. Bacci, U. G. Mueller, and T. R. Schultz. 2019. The molecular phylogenetics of Trachymyrmex Forel ants and their fungal cultivars provide insights into the origin and coevolutionary history of ‘higher-attine’ ant agriculture. Systematic Entomology 44: 939–956.
 * Tanquary M. C. 1912. A preliminary list of ants from Illinois. Trans. Ill. Acad. Sci. 4: 137-142.
 * Van Pelt A. F. 1948. A Preliminary Key to the Worker Ants of Alachua County, Florida. The Florida Entomologist 30(4): 57-67
 * Van Pelt A. F. 1966. Activity and density of old-field ants of the Savannah River Plant, South Carolina. Journal of the Elisha Mitchell Scientific Society 82: 35-43.
 * Van Pelt A., and J. B. Gentry. 1985. The ants (Hymenoptera: Formicidae) of the Savannah River Plant, South Carolina. Dept. Energy, Savannah River Ecology Lab., Aiken, SC., Report SRO-NERP-14, 56 p.
 * Van Pelt, A. 1983. Ants of the Chisos Mountains, Texas (Hymenoptera: Formicidae) . Southwestern Naturalist 28:137-142.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Warren, L.O. and E.P. Rouse. 1969. The Ants of Arkansas. Bulletin of the Agricultural Experiment Station 742:1-67
 * Weber N. A. 1966. Development of pigmentation in the pupa and callow of Trachymyrmex septentrionalis (Hymenoptera: Formicidae). Entomological News 77: 241-246.
 * Weber N. A. 1970. Northern extent of attine ants (Hymenoptera: Formicidae). Proceedings of the Entomological Society of Washington 72: 414-415.
 * Wheeler G. C., and J. Wheeler J. 1989. A checklist of the ants of Oklahoma. Prairie Naturalist 21: 203-210.
 * Wheeler W. M. 1904. The ants of North Carolina. Bulletin of the American Museum of Natural History. 20: 299-306.
 * Wheeler W. M. 1907. The fungus-growing ants of North America. Bulletin of the American Museum of Natural History 23: 669-807.
 * Wheeler W. M. 1911. Descriptions of some new fungus-growing ants from Texas, with Mr. C. G. Hartman's observations on their habits. Journal of the New York Entomological Society 19: 245-255.
 * Wheeler, G.C. and J. Wheeler. 1985. A checklist of Texas ants. Prairie Naturalist 17:49-64.
 * Whitcomb W. H., H. A. Denmark, A. P. Bhatkar, and G. L. Greene. 1972. Preliminary studies on the ants of Florida soybean fields. Florida Entomologist 55: 129-142.
 * Young J., and D. E. Howell. 1964. Ants of Oklahoma. Miscellaneous Publication. Oklahoma Agricultural Experimental Station 71: 1-42.
 * Young, J. and D.E. Howell. 1964. Ants of Oklahoma. Miscellaneous Publications of Oklahoma State University MP-71
 * Zettler J. A., M. D. Taylor, C. R. Allen, and T. P. Spira. 2004. Consequences of Forest Clear-Cuts for Native and Nonindigenous Ants (Hymenoptera: Formicidae). Ann. Entomol. Soc. Am. 97(3): 513-518.