Rogeria creightoni

A common and widespread Rogeria species. The types were collected in a residential area that was formerly mesquite-acacia savannah. Other specimens come from riparian woodland, palm-thorn forest, rain forest, pine-oak forest, cecropia forest, and cacao plantation. Most were taken in leaf litter on the ground. Some Belize specimens were under a termite nest; another in orchids.

Identification
Kugler (1994) - creightoni species group. WL 0.63-0.93mm. Clypeal apron usually with weak to distinct median notch. Eyes small, oval to circular (EL/SpL 0.29-0.64). Metanotal groove weak or absent. MHI usually 0.90-1.06. Propodeal spines long (PSI usually > 0.17), often nearly horizontal. Postpetiolar node from above usually subtrapezoidal, sometimes subrectangular; anterior edge of sternum not prominent. Sides of head distinctly rugose-areolate. Pronotal disc transversely rugose-areolate on anterior edge and longitudinally rugose-areolate behind. Scapes and extensor surfaces of tibiae with erect-suberect hairs.

See nomenclature section below and Rogeria alzatei, Rogeria belti, Rogeria brunnea, and Rogeria cornuta.

Identification Keys including this Taxon

 * Key to Rogeria workers
 * Key to US Rogeria species

Distribution
Southern Texas to Costa Rica; from about 1,500m in parts of Chiapas and Costa Rica to sea level.

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Belize, Costa Rica, Guatemala, Honduras, Mexico.

Castes
Queens have been collected in Costa Rica but remain undescribed; males have not been collected.

Nomenclature

 *  creightoni. Rogeria creightoni Snelling, R.R. 1973a: 2, fig. 1 (w.) U.S.A. See also: Kugler, C. 1994: 50.

Kugler (1994) - This species becomes quite heterogeneous with this revision. Ants from almost every locality are different from the others in some conspicuous way. Specimens from Belize have the longest propodeal spines (PSI 0.24-0.28), more prominent metapleural lobes, weak or absent petiolar keel and thicker ridges in macrosculpture. The Texas specimens have similar habitus, but have somewhat shorter propodeal spines (PSI 0.21-0.23), less prominent metapleural lobes, more distinct petiolar keel and less thickened macrosculpture. A Tamaulipas specimen is similar to the Texas specimens, but has longer, distinctly inclined propodeal spines. Specimens from Yucatán, and Chiapas are the largest (WL 0.78-0.93mm), have a prominent clypeal body, somewhat longer scapes, small circular eye, strong nuchal groove, relatively shorter propodeal spines (PSI 0.19-0.22), and head macrosculpture with sharp ridges and unusually large areolae. Specimens from La Selva, Costa Rica are similar, but have normal clypeus and sculpture. Others from Costa Rica have shorter, more inclined propodeal spines (PSI 0.16-0.20), a more distinct petiolar node and keel, and subrectangular postpetiolar node. One specimen from Oaxaca is more like those from Belize; another is more like the San Jose specimens. With little material from most localities, I did not feel confident naming a new species for each variant, but as collections improve, I will not be surprised if this species undergoes fission.

At one time during the revision I also considered describing Rogeria cornuta, Rogeria innotabilis,Rogeria leptonana, and Rogeria alzatei as variants of creightoni . But now I believe they can delineated. Comparison of creightoni  with leptonana is found in key couplet 40; comparisons with cornuta and alzatei, in their respective discussions. All known specimens of innotabilis fall within the geographic range of creightoni  and the two species are sympatric in at least one locality. All specimens of creightoni  differ from innotabilis in several ways: 1) erect hair on scapes and tibiae, 2) palpal formula 3,2, 3) clypeal apron with weak to distinct median notch, and 4) postpetiolar sternum not prominent. The regional variants differ in additional, but inconsistent ways.

A single queen from Trinidad (N. A. Weber #129) is very much like the three Costa Rican and Colombian queens provisionally assigned to innotabilis in size, general habitus, triangular mandibles, convex clypeus, robust mesosoma (MHI 1.28), propodeal spine size and shape, and subrectangular postpetiolar node, but differs in having erect hair on scapes and tibiae, little or no keel on petiolar peduncle, undulate ventral profile of postpetiole, and longitudinally oriented sculpture on the posterior head. On the basis of the pilosity, I provisionally assign the Trinidad queen to creightoni , but because of its great similarity in other respects to the innotabilis-like queens, and because neither set of queens is from an area where workers of creightoni  or innotabilis have been collected, I do not feel confident of these assignments.

Worker
Kugler (1994) - TL 2.4-3.5, HL 0.58-0.81, HW 0.51-0.72, SL 0.38-0.55, EL 0.05-0.10 (8-16 facets), PW 0.37-0.52, WL 0.63-0.93, SpL 0.1 1-0.20, PetL 0.27-0.40, PpetL 0.14-0.22mm, CI 0.85-0.91, OI 0.08-0.17, SI 0.68-0.80, PSI 0.16-0.28, MHI 0.87-1.08. N=21

Mandibles with 5-7 teeth, if 5, may have 1-2 additional basal denticles. Basal tooth subequal or larger than penultimate basal. Palpal formula 3,2. Body of clypeus projecting to anterior edge of apron or beyond. Nuchal groove weak to strong. Posterior margin of head weakly concave to convex. Mesosoma habitus variable. Propodeal spines moderately long and angled to very long and nearly horizontal, a bisecting line usually passes well above anteroventral corner of pronotum. Propodeal spiracle not especially large or prominent; located < 1 /2 diameter to almost one diameter from edge of infradental lamella. Metapleural lobes moderately to very prominent; corner broadly to narrowly rounded. Petiolarnode more or less distinct. Petiolar keel absent to moderately well developed. Sting apparatus of specimens from four localities like that of inermis, except for less angular anteroventral corner of spiracular plate, somewhat lower valve chamber height, and in Belize and Oaxaca specimens the sting shaft is higher and slightly upturned.

Laterodorsa of head longitudinally rugose to areolate; posterior head transversely arched areolate-rugose. Pronotal sides longitudinally rugose to areolate-rugose; meso- and metapleura cornfused rugose. Dorsal face of Propodeum marked anteriorly by a distinct transverse carina, then areolate and/or transversely rugose. Head and mesosoma microsculpture obscure; intervals in macrosculpture moderately shiny. Top and sides of petiolar node effaced microareolate with very weak, indistinct macrosculpture; posterior face with weak longitudinal rugulae. Postpetiolarnode with vague microsculpture on sides; smooth dorsally.

Color brownish-yellow to brownish-yellow; dorsa of head and gaster slightly darker, appendages lighter.

Type Material
Kugler (1994) - Holotype and paratype worker, UNITED STATES: Texas, Cameron County, La Feria (W. S. Creighton) [Holotype and paratype examined].