Strumigenys angulata

A woodland species that is typically collected in litter samples. It is uncommonly encountered over most of its range but is fairly common in upland hardwood and mixed pine and hardwood forests in areas of northern Mississippi (MacGown et al., 2012; Booher, 2021). Although it has been collected numerous times across the Ozarks in Arkansas, Booher (2021) reports only a single specimen from the western region has been collected near Le Flore, Oklahoma by W.G. Carter (examined by Bolton [2000]).

Identification
Bolton (2000) - A member of the Strumigenys pergandei-group. The two species angulata and Strumigenys pergandei are certainly related. They can be separated by the characters given in the key and their radically different dental arrays.

In angulata teeth 1-4 (counting from the base) are narrowly triangular and acute, with 2 and 4 longer than 1 and 3 (relative lengths 2 > 4 > 3 > 1); apices of first (basal) teeth do not meet at full closure. Tooth 4 is followed by 10-11 minute dentic1es and the row terminates in an apical tooth that is about the size of tooth 4; total dental count is 15-16.

In pergandei teeth 1, 3 and 5 (counting from the base) are narrowly triangular and acute (relative lengths 1 > 3 > 5) and first teeth deeply intersect at full closure. The intervening teeth 2 and 4 are plate-like, very broad and almost flat-topped, shorter than teeth 1 , 3 and 5; basal width of tooth 2 is twice that of tooth 1. Tooth 5 is followed by 4 dentic1es and an apical tooth that is acute and about the same size as 5; total dental count is 10.

Distribution
USA; widespread in eastern USA from Florida to Illinois, west to Missouri; in western USA occurs in Oklahoma. There is a mistakenly reported Texas record (Forster 2003:144). Forster incorrectly summarized distribution records from Bolton (2000); Bolton did not report any Texas specimens of S. angulata (Booher, 2021).

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

Biology
Brown (1953) reported, from a letter sent by the collector, that the types were collected from rotten, wet pine stumps in a swampy area. Brown (1964) - A single dealated female comes from Giant City State Park in southern Illinois (G. and A. Ulrich leg.), in the same vial with series of Strumigenys pilinasis (as S. ohioensis) and Strumigenys ornata. During two weeks of intensive collecting in Giant City State Park during the summer of 1958, I failed to retake this rare species.

Nomenclature

 *  angulata. Strumigenys (Cephaloxys) angulata Smith, M.R. 1931c: 697, pl. 1, fig. 3 (w.) U.S.A. Brown, 1953g: 54 (q.). Combination in S. (Trichoscapa): Smith, M.R., 1947f: 587; Creighton, 1950a: 304; in Smithistruma (Wessonistruma): Brown, 1948e: 106; Brown, 1953g: 54; in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 115. See also: Bolton, 2000: 115.

Worker
Bolton (2000) - TL 2.2-2.3, HL 0.56-0.60, HW 0.42-0.46, CI 73-79, ML 0.16-0.19, MI 28-33, SL 0.28-0.31, SI 65-69, PW 0.26-0.28, AL 0.58-0.64 (7 measured).

Basal lamella of mandible triangular and short; apices of lamellae widely separated when mandibles fully closed. Basal lamella very widely separated from basal tooth, distance between them about equal to the dentate length of the mandible in full-face view. Basal and three succeeding teeth on mandible triangular and acute, the second tooth longer than the basal. Anterolateral angles of clypeus distinctly angular in full-face view, located far beyond the line of the mandibular outer margins. Eye small, with only about 4-6 ommatidia in total. Preocular laminae very broad in full-face view, their outer margins markedly convergent posteriorly. Leading edge of scape obtusely angulate at subbasal bend. Cephalic dorsum without standing hairs of any form. Apicoscrobal hair absent. Pronotal humeral hair usually absent but one present in some specimens. Dorsum of mesonotum with a pair of erect simple hairs. Disc of postpetiole without posteriorly curved spatulate hairs. Middle and hind basitarsi each with 1-2 long fine flagellate hairs.

Type Material
Bolton (2000) - Lectotype (by designation of Brown, 1953a: 54) and paralectotype workers, U. S.A.: Mississippi, Louisville, 15.v.1920 (M. R. Smith) [examined].

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.
 * Brown W. L., Jr. 1953. Revisionary studies in the ant tribe Dacetini. Am. Midl. Nat. 50: 1-137.
 * Dash S. T. and L. M. Hooper-Bui. 2008. Species diversity of ants (Hymenoptera: Formicidae) in Louisiana. Conservation Biology and Biodiversity. 101: 1056-1066
 * Deyrup, M. and S. Cover. 2009. Dacetine Ants in Southeastern North America (Hymenoptera: Formicidae). Southeastern Naturalist 8(2):191-212
 * 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
 * Forster J.A. 2005. The Ants (hymenoptera: Formicidae) of Alabama. Master of Science, Auburn University. 242 pages.
 * Hill, J.G. 2006. Ants collected at Okatibbee Lake, Lauderdale County, Mississippi
 * 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., 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 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 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., 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.
 * MacGown, J.A., R.L. Brown and J.G. Hill. 2005. An Annotated List of the Pyramica (Hymenoptera: Formicidae: Dacetini) of Mississippi. Journal of the Kansas Entomological Societ 78 (3):285-289
 * MacKay W. P. and Anderson R. S. 1993. New distributional records for the ant genus Smithistruma (Hymenoptera: Formicidae) in southern United States. The Southwestern Naturalist 38: 388-389
 * 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.
 * Smith M. R. 1931. A revision of the genus Strumigenys of America, north of Mexico, based on a study of the workers (Hymn.: Formicidae). Annals of the Entomological Society of America 24: 686-710.