Strumigenys angulata

A woodland species that is typically collected in litter samples.

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 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 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].