Rogeria alzatei

All specimens were apparently taken as strays or in Berlese or Winkler sampling in moist forests from sea level to 1000m.

Identification
Kugler (1994) - creightoni species group. WL 0.51-0.70mm, most < 0.65mm. Mandibles subtriangular (usually) to triangular. Clypeus usually truncate. Eye usually moderately large, oval (10-14 facets, OI 0.17-0.20 in types), but occasionally half as large and elliptical. Nuchal groove weak to strong. Mesosoma compact (MHI 0.90-1.07). Propodeal spines usually slender, inclined. Petiolar peduncle with little or no keel. Postpetiolar node from above usually subrectangular; anterior edge of sternum not prominent. Macrosculpture areolate on head sides. Posterior head transversely rugose-areolate. Pronotal disc rugose to rugose- areolate. No erect hair on scapes or legs.

Given the geographic variation within alzatei, the species as a whole is difficult to distinguish clearly from Rogeria creightoni, Rogeria innotabilis, and Rogeria leptonana. But if one compares only those specimens of alzatei that are in sympatry or parapatry with those three species, the differences are clear. The Panamanian alzatei workers differ from Central American creightoni, innotabilis, and leptonana in having: 1) subtriangular mandibles, 2) truncate clypeal apron, 3) larger, elongate-oval eye (01 0.17-0.20), 4) more compact mesosoma (MHI 1.01-1.07), and 5) petiolar peduncle without a keel. They are also smaller than creightoni and innotabilis workers (WL 0.51-0.61mm vs. 0.66-0.93mm in creightoni and 0.66-0.73mm in innotabilis). Additional differences from leptonana are palpal formula (2,2 vs. 3,2 in leptonana), longer propodeal spines (PSI 0.19-0.20 vs. < 0.16 in leptonana), and lack of erect hair on scapes.

See also the sibling species Rogeria scobinata and the discussions of Rogeria belti, Rogeria curvipubens, Rogeria micromma, Rogeria tribrocca and Rogeria merenbergiana.

Distribution
Kugler (1994) - The range of alzatei is from Panama to Paraguay, from western slopes of the Andes in Colombia to the Eastern coast of Brazil. It also occurs in the Dominican Republic.

Distribution based on Regional Taxon Lists
Neotropical Region: Colombia, Dominican Republic, Greater Antilles, Guyana, Panama, Paraguay.

Castes
Males have not been collected.

Nomenclature

 *  alzatei. Rogeria alzatei Kugler, C. 1994: 52, figs. 58-60, 99 (w.q.) PANAMA.

The extent of variation within this species makes me question whether this is a single species, but external characters that can be used in a key are either not marked enough to discount individual variation or not concordant. Further complicating the picture is the surprising amount of variation within four specimens from the same region of Peru, and unique sets of features found in single specimens from northern Colombia, Rio de Janeiro, and Peru. Specimens from Dominican Republic strongly resemble Rogeria creightoni workers from the same localities, but differ in lacking erect hair on the scapes and tibiae and in having narrower propodeal spines.

Worker
Holotype and Paratypes. TL 1.9-2.2 (2.2), HL 0.51-0.56 (0.54), HW 0.45-0.48 (0.47), SL 0.32-0.36 (0.35), EL 0.07-0.09 (0.09) (11-14 facets), PW 0.32-0.37 (0.35), WL 0.51-0.61 (0.59), SpL 0.10-0.12 (0.11), PetL 0.21-0.26 (0.23), PpetL 0.12-0.14 (0.13)mm, CI 0.87-0.88 (0.87), OI 0.17-0.20 (0.19), SI 0.72-0.74 (0.74), PSI 0.19-0.21 (0.19), MHI 1.01-1.07 (1.05). N=11

Mandible subtriangular; 5-6 teeth, two basal teeth small, sub equal. Palpal formula 2,2. Clypeal apron truncate, with distinct corners; body of clypeus does not project to edge of apron. Posterior outline of head continuously convex. Nuchal groove indistinct in lateral view. Mesosoma's evenly convex dorsal profile ends abruptly fore and aft by rather sharp angles and by transverse sculpture. Metanotal groove weak or absent. Propodeal spines straight, narrow; a bisecting line passes through or just above anteroventral corner of pronotum. Corner of metapleural lobes a narrowly rounded right angle. Petiolar node evenly rounded front to back. Pygidium in the five specimens dissected with no piligerous tubercles.

Head laterodorsa rugose-areolate to areolate; sides more coarsely areolate. Microsculpture vestigial, producing irregular intervals on head dorsum and nearly smooth intervals on sides and posterior. Anterior edge of pronotal disc with two transverse rugae. Promesonotal dorsum longitudinally rugose with numerous lateral spurs that sometimes connect, forming areolae. No macrosculpture on dorsal face of propodeum. Lateral pronotum longitudinally rugose-areolate. Meso- and metapleura with scattered, irregular rugae. Vestigial rugae on sides and back of petiolar node. Vague microsculpture makes roughened intervals on mesosoma, petiole and much of postpetiole; apex of postpetiolar node smooth.

Body yellowish-brown to reddish-brown with slightly darker head and gaster dorsa (black to naked eye); legs and antennae lighter, more yellowish or yellowish-brown.

Nontype Workers. —TL 1.9-2.5, HL 0.50-0.66, HW 0.42-0.56, SL 0.31-0.46, EL 0.05-0.10 (4-21 facets), PW 0.29-0.39, WL 0.51-0.70, SpL 0.09-0.13, PetL 0.21-0.28, PpetL 0.11-0.15mm, CI 0.81-0.88, OI 0.08-0.20, SI 0.71-0.85, PSI 0.15-0.21, MHI 0.90-1.07. N=32

Specimens from Guyana, French Guiana, and the Caribbean coast of Colombia extend the description as follows: Mandibles triangular with 3-4 teeth plus 4 basal denticles. Clypealapron evenly convex, sometimes with medial emargination. Some with only 7-8 facets in the eyes. Some with wider propodeal spines or slightly downtumed tips. Petiolar keel sometimes distinct. Macrosculpture on head or pronotum more areolate.

Dominican Republic specimens have a convex clypeus, a distinct metanotal groove, and sub trapezoidal postpetiolar node.

Specimens from Peru, Brazil, and Paraguay extend the description somewhat differently: Palpal formula 3,2. Clypeal apron usually truncate with rounded corners; occasionally convex. Several specimens with a somewhat prominent clypeal body. Generally with smaller, elliptical eyes (OI of most 0.10-0.16), but the four workers from the Puerto Maldonado vicinity of Peru possess both the smallest eyes and largest eyes of the species (4 and 21 facets, OI 0.08 and 0.20). Nuchal groove forms a distinct notch in the head of one Peruvian worker. Mesosoma generally less compact (MHI 0.93-1.03). Petiolar keel weak to distinct. Some with postpetiolar node slightly wider in anterior half and shape Posterior pygidium with small tubercles in a Paraguayan specimen dissected. Sting apparatus with reduced anterodorsal corner of quadrate plate in a Brazilian worker.

Queen
Paratype and Nontypes. —TL 2.4-2.8, HL 0.56-0.60, HW 0.51-0.53, SL 0.35-0.38, EL 0.13-0.14, PW 0.44-0.49, WL 0.70-0.79, SpL 0.14-0.15, PetL 0.26-0.30, PpetL 0.15-0.16mm, CI O.88-0.92, OI 0.25-0.26, SI 0.70-0.72, PSI O.19-0.20, MHI 1.17-1.18. N=2

Both collected in the same localities as alzatei workers (BCI, Panama; Quebrada Susumuco, Colombia), but not in nest series. They most resemble alzatei workers in characteristic shapes of clypeus, mandible, mesosoma, propodeal spines, petiole and postpetiole, as well as sculpture and pilosity. Mesoscutellum projects slightly beyond posterior edge of metanotum. Posterior head rugose-areolate; no tubercles. Middorsum of head covered with erect hairs.

Type Material
Holotype locality. PANAMA: Canal Zone, Barro Colorado Island (BCI), 2-VII-79, W. L. Brown.

Paratype localities. PANAMA: 3 workers, 1 queen from holotype locality [mouthparts, sting, 1 worker coated for SEM] (, MCZC); 2 workers, BCI, IV-V-1942, #4953 (J. Zetek) ; 2 workers, BCI, VI-X-1943, #5105 (J. Zetek) [whole specimen slide mounted] USNM; 1 worker, BCI, I-1960 (W. L. Brown & E. S. McCluskey) MCZC; 1 worker, BCI, 7-III-1975, FP#10 (C Toft & S. Levings) LACM; 1 worker, Punta de los Chivos, W side Gatun Lake, 3km SW Gatlin, 100m, 3-9-VII-1979 (W. L. Brown) MCZC; 1 worker, Bocas del Toro, Pipeline Road, 300m, 8.53N 82.lOW, 18-VII-1987, #633 (D. M. Olson).

Etymology
The species is named in honor of a courageous Colombian intellectual and friend, Isaac Alzate.

References based on Global Ant Biodiversity Informatics

 * Achury R., and A.V. Suarez. 2017. Richness and composition of ground-dwelling ants in tropical rainforest and surrounding landscapes in the Colombian Inter-Andean valley. Neotropical Entomology https://doi.org/10.1007/s13744-017-0565-4
 * Fernandes I., and J. de Souza. 2018. Dataset of long-term monitoring of ground-dwelling ants (Hymenoptera: Formicidae) in the influence areas of a hydroelectric power plant on the Madeira River in the Amazon Basin. Biodiversity Data Journal 6: e24375.
 * Fernández F., E. E. Palacio, W. P. MacKay, and E. S. MacKay. 1996. Introducción al estudio de las hormigas (Hymenoptera: Formicidae) de Colombia. Pp. 349-412 in: Andrade M. G., G. Amat García, and F. Fernández. (eds.) 1996. Insectos de Colombia. Estudios escogidos. Bogotá: Academia Colombiana de Ciencias Exactas, Físicas y Naturales, 541 pp
 * Franco W., N. Ladino, J. H. C. Delabie, A. Dejean, J. Orivel, M. Fichaux, S. Groc, M. Leponce, and R. M. Feitosa. 2019. First checklist of the ants (Hymenoptera: Formicidae) of French Guiana. Zootaxa 4674(5): 509-543.
 * Groc S., J. Orivel, A. Dejean, J. Martin, M. Etienne, B. Corbara, and J. H. C. Delabie. 2009. Baseline study of the leaf-litter ant fauna in a French Guianese forest. Insect Conservation and Diversity 2: 183-193.
 * Kugler C. 1994. A revision of the ant genus Rogeria with description of the sting apparatus (Hymenoptera: Formicidae). Journal of Hymenoptera Research 3: 17-89.
 * 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.
 * Perez-Gelabert D. E. 2008. Arthropods of Hispaniola (Dominican Republic and Haiti): A checklist and bibliography. Zootaxa 1831:1-530.
 * Pires de Prado L., R. M. Feitosa, S. Pinzon Triana, J. A. Munoz Gutierrez, G. X. Rousseau, R. Alves Silva, G. M. Siqueira, C. L. Caldas dos Santos, F. Veras Silva, T. Sanches Ranzani da Silva, A. Casadei-Ferreira, R. Rosa da Silva, and J. Andrade-Silva. 2019. An overview of the ant fauna (Hymenoptera: Formicidae) of the state of Maranhao, Brazil. Pap. Avulsos Zool. 59: e20195938.
 * Silvestre R., M. F. Demetrio, and J. H. C. Delabie. 2012. Community Structure of Leaf-Litter Ants in a Neotropical Dry Forest: A Biogeographic Approach to Explain Betadiversity. Psyche doi:10.1155/2012/306925
 * Wild, A. L. "A catalogue of the ants of Paraguay (Hymenoptera: Formicidae)." Zootaxa 1622 (2007): 1-55.