Strumigenys metazytes

Identification
Bolton (2000) - A member of the Strumigenys pulchella-group. Four species in this group (Strumigenys abdita, Strumigenys creightoni, Strumigenys deyrupi, Strumigenys metazytes) do not have hairs on the anterior or lateral clypeal margins that are recurved or reflexed. Of these creightoni lacks erect hairs on the vertex close to the occipital margin, lacks an apicoscrobal hair, lacks a fine projecting hair at the pronotal humerus, and lacks standing pilosity on the mesonotum. In the other three species filiform or flagellate hairs are present at all these locations.

P. deyrupi separates from both abdita and metazytes as its main pilosity is entirely of long fine flagellate hairs. These occur as a pair on the vertex close to the occipital margin, a pair on the pronotal dorsum (as well as at the humeri), another pair on the mesonotum, and in numbers on the waist segments and especially the first gastral tergite. In both abdita and metazytes the hairs in many or all of these positions are stouter, simple and stiffly filiform, and at most evenly shallowly curved.

Of the last two species abdita is generally larger and its mandibles are usually longer (HL 0.53-0.60, HW 0.40-0.43, MI 17-22) than in metazytes (HL 0.51-0.52, HW 0.36-0.38, MI 16-17). Also, in abdita the anterior clypeal margin is very wide and has abruptly rounded anterolateral angles. The clypeal dorsum has broadly spatulate to spoon-shaped ground-pilosity that is very dense and conspicuous, and is very similar in shape and size to the hairs that fringe the lateral margins. Standing pilosity on the first gastral tergite is usually restricted to an apical and a basal transverse row, though some samples are known which have intermediate hairs present. By comparison metazytes has a short but very shallowly convex anterior clypeal margin that curves evenly into the lateral margins through widely rounded anterolateral angles. Its clypeal dorsum has minute inconspicuous spatulate ground-pilosity that is very much smaller than the large hairs that fringe the lateral margins. Pilosity on its first gastral tergite is more or less evenly distributed over the sclerite.

The only known Neotropical member of the pulchella-group, Strumigenys dispalata, is closest related to metazytes. Differentiation of the two is given under dispalata.

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



Nomenclature

 *  metazytes. Pyramica metazytes Bolton, 2000: 121, fig. 108 (w.) U.S.A. Combination in Strumigenys: Baroni Urbani & De Andrade, 2007: 123

Worker
Holotype. TL 1.9, HL 0.52, HW 0.36, CI 69, ML 0.09, MI 17, SL 0.28, SI 78, PW 0.23, AL 0.50. Anterior clypeal margin extremely shallowly convex, almost transverse in full-face view. Dorsum of clypeus with inconspicuous subappressed small spatulate hairs that are very much smaller than the anteriorly curved spoon-shaped hairs on the lateral clypeal margins. Eye with 3 ommatidia in the longest row (ca 6-7 ommatidia in total). Apicoscrobal hair present, flagellate. Cephalic ground-pilosity curved and narrowly spatulate; vertex near occipital margin with a pair, or transverse row of 4, longer more slender hairs that are filiform and more or less erect. Pronotal humeral hair very long and flagellate. Pronotal dorsum with 1 pair of erect filiform hairs. Mesonotal dorsum anteriorly with a pair of flagellate hairs, more posteriorly with at least 1 pair of shorter filiform hairs. Hairs on first gastral tergite erect, filiform and feebly curved, their apices weakly flattened or split. Hind basitarsus with a fine flagellate hair projecting from the dorsal (outer) surface close to its base. Dorsal alitrunk and petiole node finely superficially reticulate-punctate everywhere. Basigastral costulae coarse, strongly developed, extending over the basal quarter of the tergite.

Paratypes. TL 1.8-1.9, HL 0.51-0.52, HW 0.36-0.38, CI 70-74, ML 0.08-0.09, MI 16-18, SL 0.27-0.28, SI 73-76, PW 0.24-0.25, AL 0.48-0.50 (4 measured). Eye with 2-3 ommatidia in longest row (ca. 5-6 in total). Description of pilosity above is composite as the few available specimens all show some degree of abrasion. Mesonotal standing hairs may be more numerous than described.

Type Material
Holotype worker U.S.A. Kentucky, Edmonton Co., Mammoth Cave Nat. Park, Bruce Hollow, 24-27.viii.1967, Berl. 101 FM(HD), #67-145, log stump litter (S. Peck & A. Fiske). Paratypes 4 workers, U.S.A. Tennessee, Sevier Co., Chilhowee Mts, iii.1951, STR-199 (A. C. Cole).

Determination Clarifications
Bolton (2000) - It is possible that members of this species may be among the material mentioned by Brown (1953a:90) as possible new species, being noted again by Brown (1964:199) in his discussion of the “sp. near missouriensis”. However, I have not seen any of Brown's material that is obviously referable to metazytes, all that I have seen of it represents hyalina, a species belonging in the rostrata-group.