Strumigenys tlaloc

Identification
Bolton (2000) - The only member of the Strumigenys tlaloc-group. S. tlaloc is very distinctive when compared to all other Neotropical members of the genus. Its real relatives are probably not Neotropical but should instead be sought among the clypeata-group of the North American fauna.

Distribution based on Regional Taxon Lists
Neotropical Region: Mexico.

Nomenclature

 *  tlaloc. Pyramica tlaloc Bolton, 2000: 244, figs. 164, 195 (w.) MEXICO. Combination in Strumigenys: Baroni Urbani & De Andrade, 2007: 129

Worker
Holotype. TL 2.2, HL 0.60, HW 0.41, CI 68, ML 0.09, MI 15, SL 0.38, SI 93, PW 0.27, AL 0.60. Anterior clypeal margin at the midpoint with a low projecting tumulus that is slightly more convex than the outline of the margin on each side of it. Clypeal dorsum less strongly sculptured than the reticulate-punctate cephalic dorsum posterior to it. Hairs on clypeal dorsum short and spatulate, strongly curved anteriorly. Dorsum of head behind clypeus with much longer ground-pilosity that is narrowly spatulate and curved; dorsum also with two pairs of very long erect flagellate hairs, first pair close to highest point of vertex and second pair behind the highest point. In full-face view dorsolateral margin of head with 4 long, freely laterally projecting flagellate hairs: first arising midway between frontal lobe and level of eye, second at level of eye, third apicoscrobal, fourth very close to occipital corner. Eye small, with only 5-6 ommatidia in total. Dorsal alitrunk with a vertically directed pair of long fine flagellate hairs on the pronotum, as well as the humeral hairs, and another pair on the mesonotum. Ground pilosity of dorsal alitrunk similar to head. Petiole and postpetiole with a number of flagellate hairs, directed dorsally and laterally, and numerous flagellate hairs present on first gastral tergite. Femora, tibiae and basitarsi of middle and hind legs have fine dense apically directed short hairs that are simple or narrowly spatulate and subdecumbent to appressed. In addition the dorsal (outer) surfaces of each of these segments has 1-3 elongate fine freely projecting flagellate hairs. With alitrunk in profile the dorsum with a median lamellate crest that arises on the mesonotum, spans the metanotal groove and terminates on the anterior quarter of the propodeum. In dorsal view this crest is seen to bifurcate on the propodeum, with a carina running to the base of each tooth. Dorsolateral margins of mesonotum and propodeum bearing a narrow longitudinal cuticular crest that is broadest anteriorly on the mesonotum. Dorsal alitrunk and upper half of propodeal declivity reticulate-punctate, alitrunk sides almost entirely smooth. Petiole node cuneate in profile, with a deep ventral spongiform curtain and large lateral lobe. In dorsal view petiole node broader than long and weakly punctate. Postpetiole disc glassy smooth, the segment with large lateral and ventral spongiform lobes; disc completely surounded by spongiform tissue in dorsal view, the spongiform tissue narrowest anteriorly. Basigastral costulae extremely short on the tergite proper, but each costula strongly developed and distinct. First gastral tergite otherwise glassy smooth.

Type Material
Holotype worker, Mexico: Ixtlan (Ixltan on label), xi.1923 (W.M. Mann). Most of the flagellate hairs on the left dorsolateral margin of the head of the holotype have been abraded and there is a small blob of glue adhering to the surface close to the scrobe apex.