Strumigenys talpa

A ground nesting species that foragers in leaf litter.

Identification
Bolton (2000) - A member of the Strumigenys talpa-group. As Brown (l953a) has pointed out, the three older species currently placed in this group are very closely related, and best separated by differences in their clypeal pilosity. Strumigenys wrayi has hairs on the anterior clypeal margin that curve away from the midline and spoon-shaped hairs on the lateral margins that are weakly reflexed; hairs on the clypeal dorsum are inclined posteriorly. Clypeal hairs with these orientations are absent from Strumigenys filitalpa and talpa. In particular the fringe of hairs on the lateral margins curves anteriorly; those of talpa being decidedly spatulate or weakly spoon-shaped whilst those of filitalpa are slender and filiform. Neither has posteriorly inclined hairs on the clypeal dorsum.

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



Biology
Wesson and Wesson (1939) from their description of the synonymized S. venatrix: described from a colony containing about 60 workers. Eight colonies and occasional scattered workers have been taken in Pike, Lawrence, Scioto and Adams Counties. The species is definitely a soil or humus dweller and forages for Collembola under the leaves and dead vegetable matter on the surface of the ground. So far as we can tell, it is not associated with other species for the purpose of obtaining the Collembola about their nest. Specific examples of the colonies may give a better idea of the habitus. A colony was found in a small opening near the edge of some young oak woods on a rather dry, gently-sloping hillside. The soil was a sandy clay. Several workers were first observed around a light cover of dead leaves. One of these, carrying a springtail in its mandibles, led to the nest, the entrance of which, was a tiny hole under a flake of stone in the middle of a small bare area 30 sq. cm. in extent. Just below the surface, this hole widened out into a spacious, elongate chamber 5 to 10 mm. in diameter and 10 cm. in length, which appeared to be the hollow interior of a dead and decayed root. Another colony was found in the grassy humus on the edge of a bushy thicket in a field. A colony of Aphaenogaster fulva was under an adjacent stone. Four colonies, including the type, were found in a grassy clearing in some dry, open woods. Two of these colonies were on the surface in the tangled roots of the grass, while the other 2 were in the soil 2 to 8 cm. below the surface. Galleries of ''Camponotus americanus ran close to one nest, but we were unable to find any connection between the two. Two colonies were 2ound in the cedar thicket described above under Strumigenys missouriensis. One of these was nesting in an opening at the bottom of the humus, the other in a small cavity at the base of an old rotted cedar stump. Stray workers in these and other places were often found by pulling back the top cover of the humus in places where springtails were abundant.

Nomenclature

 *  talpa. Strumigenys (Cephaloxys) talpa Weber, 1934b: 63, fig. 1 (w.) U.S.A. Brown, 1953g: 77 (q.m.); Wheeler, G.C. & Wheeler, J. 1955a: 141 (l.). Combination in S. (Trichoscapa): Smith, M.R., 1947f: 587; Creighton, 1950a: 310; in Smithistruma: Smith, M.R., 1951a: 828; Brown, 1953g: 76; in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 128. Senior synonym of venatrix: Wesson, 1949: 21. See also: Wilson, 1954: 486; Bolton, 2000: 132.
 * venatrix. Strumigenys (Cephaloxys) venatrix Wesson, L.G. & Wesson, R.G., 1939: 103, pl. 3, fig. 5 (w.) U.S.A. Combination in S. (Trichoscapa): Smith, M.R., 1943f: 307. Junior synonym of talpa: Wesson, 1949: 21; Brown, 1953g: 76.

Worker
TL 2.0-2.2, HL 0.53-0.60, HW 0.36-0.39, CI 64-69, ML 0.08-0.11, MI 15-19, SL 0.25-0.29, SI 66-76, PW 0.23-0.26, AL 0.50-0.59 (20 measured).

Fully closed mandibles with a basal gap between anterior clypeal margin and basal tooth that is distinctly longer than length of basal tooth. Anterior clypeal margin very evenly and shallowly broadly convex. In full-face view lateral clypeal margins with a continuous fringe of distinctly projecting, anteriorly curved hairs that are spatulate to very feebly spoon-shaped. Row of hairs on clypeal dorsum closest to lateral margin also project outward and curve anteriorly above the principal row; these hairs shorter than the principal marginal hairs but longer than those situated more centrally on the dorsum. Anterior clypeal margin without hairs that curve away from the midline. Dorsum of clypeus densely clothed with small spatulate hairs that curve anteriorly or anterolaterally. Dorsolateral margin of head with a single projecting flagellate hair, in apicoscrobal position. Dorsum of head close to occipital margin with 1-2 pairs of flagellate hairs. Flagellate hairs also present at pronotal humeri, on pronotal dorsum and mesonotum (1 pair each), on first gastral tergite and dorsal (outer) surfaces of hind tibia and basitarsus. Basigastral costulae strongly developed, extending one-third or more the length of the tergite.

Type Material
Holotype worker, U. S. A. Illinois, Herod, 12.x.1933 (T.H. Frison & H.H. Ross) [not seen].