Rogeria tsumani

Known only from the type locality in Guyana. The two known specimens of Rogeria tsumani were collected from a rotten branch that fell off a tree from about 30 meters height as Weber was walking through the forest (N.A. Weber, field notes, in MCZC archives). Weber reported looking through the rotting branch for the Rogeria nest, but he could not locate it. Rogeria tsumani is probably a canopy-dwelling species. (LaPolla and Sosa-Calvo 2006)

Identification
LaPolla and Sosa-Calvo (2006) - Mesosoma smooth and shiny, with scattered short appressed hairs; propodeal spines long, slightly inclined posterad; petiole pedunculate and with a distinct node, convex in lateral view.

Only four species of Rogeria are known in which the mesosomal dorsum bears only appressed hairs: Rogeria bruchi, Rogeria foreli, Rogeria prominula, and R. tsumani. Both R. bruchi and R. foreli possess a much more erect and distinct petiolar node compared to R. tsumani, and the propodeal spines of R. bruchi and R. foreli are at roughly right angles to the longitudinal axis of the mesosoma. In R. tsumani, in contrast, the propodeal spines are roughly parallel to the longitudinal axis of the mesosoma. Rogeria prominula has a unique propodeal shape and a rugoreticulate head and mesosoma. In Kugler’s (1994) key, R. tsumani would key to ''R. bruchi. Rogeria tsumani is a larger species (TL 3.7–3.9 in R. tsumani vs. 2.2–2.6 in R. bruchi'') with smaller eyes and darker brown coloration. Kugler (1994) constructed six informal species-groups. While he placed the majority of species into these species-groups, there was still a substantial number that he could not reliably place. Rogeria tsumani similarly fails to fall neatly into a species group.

Distribution based on Regional Taxon Lists
Neotropical Region: Guyana.

Castes
Only known from workers.

Nomenclature

 *  tsumani. Rogeria tsumani LaPolla & Sosa-Calvo, 2006: 61, figs. 11, 22 (w.) GUYANA.

Worker
Head: subquadrate in dorsal view; dorsolateral surface of head with widely spaced punctures, smooth and shiny in between; dorsomedian surface of head weakly longitudinally carinulate; nuchal grooves very shallow, not visible in lateral view; mandibles triangular; inner margin with 5 teeth, apical tooth largest; clypeal apron with shallow median depression. Mesosoma: promesonotum faintly longitudinally carinulate; promesonotal suture weakly marked; mesopleural suture incomplete; anepisternum and metapleuron weakly rugose; katepisternum smooth and shiny; dorsum of propodeum transversely rugose; propodeal spines long (SpL= 0.20–0.22) and slightly inclined posterad. Metasoma: petiole pedunculate, weakly rugulose, becoming smooth ventrally; petiolar ventral process smooth and shiny with a short anterior keel; postpetiole node tall, smooth and shiny; postpetiolar ventral margin rugose, with a short anterior keel. Body with scattered short, appressed hairs. Overall body color reddish-dark brown, with propodeum darker brown, and light brown legs. Queen and male unknown. Measurement: holotype and paratype (N= 2): TL= 3.75–3.88, HL= 0.86–0.88, HW= 0.69–0.72, ML=0.39–0.41, SL= 0.52–0.55, EL= 0.12–0.15, PW= 0.55–0.55, WL= 0.95–0.97, SpL=0.20–0.22, PL= 0.44–0.48, FLW= 0.23–0.25, PPL= 0.22–0.23, GL= 0.89–0.89, CI=80–82, OI= 17–22, SI= 60–76, PSI= 21–23.

Type Material
Holotype worker, GUYANA: Oronoque River just above juncture with New River, 29 July 1936 [coordinates determined by JSL: 2° 45’00” N 57° 26’00” W], coll. N.A. Weber. Paratype worker same locality as holotype. Holotype in, paratype in.

Etymology
Named in honor of Dr. Ted Suman, Research Associate at the National Museum of Natural History. Without Ted’s hard work and dedication to the Guyana Ant Project much of the research being conducted on the Guyana ant fauna would not be possible.

References based on Global Ant Biodiversity Informatics

 * Lapolla J. S., and J. Sosa-Calvo. 2006. Review of the ant genus Rogeria (Hymenoptera: Formicidae) in Guyana. Zootaxa 1330: 59-68.
 * Lapolla, J. S., and B. L. Fisher. "Review of the ant genus Rogeria (Hymenoptera: Formicidae) in Guyana." Zootaxa 1330 (2006): 59-68.