Rogeria merenbergiana

Rogeria merenbergiana is found at high elevations (1300-2300m) in the Andes of Ecuador and southern Colombia. Specimens have been collected from litter samples in moist broadleaf forest and bamboo-moss forest. A nest was found in a rotten log in a pasture.

Identification
Kugler (1994) - creightoni species group. WL 0.69-0.83mm. Pal pal formula 3,2. Clypeal apron with median concavity. Eye small, elliptical; EL/SpL 0.67-0.86. Anterior edge of pronotal disc without a strong transverse carina. MHI 0.91-1.01. Promesonotum and metanotum with distinct profiles — promesonotum convex, metanotum usually flat. Propodeal spines short, straight. Postpetiole from above subtrapezoidal. Mesosoma and sides of head rugose (sides of head sometimes effaced rugose-areolate). Erect hair on scapes and middle and hind tibiae.

Rogeria unguispina from the mountains of Venezuela (1100-2000m) is also very similar in size, sculpture, pilosity and color to Rogeria merenbergiana, and the two species intergrade with respect to mesosoma shape and petiole shape. It is quite possible that these are geographic variants of the same species, but all unguispina specimens presently available have more elongate eyes and have a strong carina running across the shoulders, and specimens dissected differ in palpal formula. Most unguispina specimens also have downcurved propodeal spines, concave posterior face of petiolar node, and a broad, shallow metanotal groove. See also Rogeria nevadensis for comparisons with that species from high elevations in Colombia.

Rogeria alzatei occurs in Colombia, but so far has not been found above 1000m. These ants are usually smaller than merenbergiana (WL 0.51-0.68mm), lack erect hair on the scapes, and lack a distinct metanotal profile.

Rogeria creightoni, so far only known from North and Central America, is related to merenbergiana, but generally has: 1) longer, less inclined propodeal spines, 2) less distinct metanotum, and 3) stronger, rugose-areolate sculpture on sides of head.

Rogeria belti from Central America is the same size and also generally has a more or less definite step in mesosoma profile at metanotal groove, but has: 1) larger eye, 2) longer propodeal spines, 3) more rounded postpetiolar node, 4) more areolate pronotum, and 5) mesosoma dorsum without two distinct types of hairs.

Key to Rogeria workers

Distribution
Colombia and Ecuador

Distribution based on Regional Taxon Lists
Neotropical Region: Colombia, Ecuador.

Castes
Males have not been collected.

Nomenclature

 *  merenbergiana. Rogeria merenbergiana Kugler, C. 1994: 46, figs. 46-48 (w.q.) COLOMBIA.

Worker
Holotype and Paratype. TL 2.7-3.1 (3.0), HL 0.69-0.71 (0.71), HW 0.57-0.62 (0.61), SL 0.46-0.52 (0.50), EL 0.07-0.09 (0.08) (8-14 facets), PW 0.42-0.47 (0.45), WL 0.74-0.83 (0.80), SpL 0.10-0.14 (0.12), PetL 0.28-0.36 (0.335), PpetL 0.15-0.18 (0.16)mm, CI 0.83-0.88 (0.85), OI 0.13-0.15 (0.13), SI 0.80-0.84 (0.83), PSI 0. 13-0.17 (0.15), MHI 0.91-1 .00 (0.93). N=6

Mandibles with 6-7 teeth decreasing in size basad and basal tooth as large or larger than penultimate basal. If 6 teeth, may have 1-2 additional denticles among basal teeth. Body of clypeus not strongly produced. Nuchal groove weak. Posterior outline of head evenly convex. Propodeal spiracle one diameter, or slightly less, from edge of infradental lamella. Metapleural lobes low; edges perpendicular. Petiolar node with a more or less distinct angle between dorsal and posterior faces. Petiolar peduncle with weak keel. Postpetiole with longer anterior face and short posterior face meeting at a narrow apex. Postpetiolar node from above as in unguispina. Postpetiolar sternum short, weakly concave; anterior edge square.

Laterodorsa of head longitudinally rugose-areolate. Posterior head with rugae diverging from midline or transversely arching; few if any cross-ridges. Sides of head longitudinally rugose. Anterior pronotal disc transversely rugose to rugose-areolate; rest of promesonotal dorsum longitudinally rugose. Dorsal face of propodeum areolate-rugose. Lateral mesosoma rugose; less regularly so on meso- and metapleura. Microsculpture on head and mesosoma effaced; intervals quite smooth and shiny, especially on sides and back of head. Petiole distinctly microareolate; sides of node vaguely rugose to vaguely areolate; posterior face with strong ridges. Postpetiole effaced microareolate and very sparsely and vaguely rugose.

Color very dark reddish brown to yellowish brown; appendages and often sides of mesosoma and gaster lighter.

Nontypes. —TL 2.6-3.0, HL 0.63-0.71, HW 0.53-0.60, SL 0.43-0.49, EL 0.08-0.09 (12-15 facets), PW 0.40-0.43, WL 0.69-0.77, SpL 0.10-0.13, PetL 0.29-0.33, PpetL 0.16-0.18mm, CI 0.84-0.85, OI 0.14-0.15, SI 0.79-0.82, PSI 0. 14-0.17, MHI 0.95-1.01. N=3

Little difference from types. Some slightly smaller, but with slightly larger eye for size. Generally higher mesosoma height index. Posterior head sometimes transversely arching rugose-areolate. Sides of head rugose-areolate, but effaced posterior to eye. Promesonotal dorsum longitudinally rugose to rugose-areolate. Lateral mesosoma rugose-areolate.

Queen
Paratype And Nontypes. TL 3.3-3.7, HL 0.70-0.75, HW 0.61-0.64, SL 0.48-0.52, EL 0.16-0.17, PW 0.58-0.60, WL 0.98-1.15, SpL 0.15-0.17, PetL 0.34-0.39, PpetL 0.19-0.20mm, CI O.86-0.88, SI 0.78-0.80, PSI 0.14-0.16, MHI 1.13-1.19. N=3

Mandible with 6-7 teeth; if 6, basal larger than penultimate tooth. Clypeus evenly convex to weakly emarginate. Posterior outline of head strongly convex. Mesosoma and waist habitus shown in Fig. 48. Sculpture mostly like worker. Anterior pronotum areolate, becoming more rugose on sides. Half to nearly all of ventral half of mesopleura smooth; the rest of meso- and metapleura and meso- and metanota longitudinally rugose-carinate. Dorsal face of Propodeum transversely rugose. Intervals on mesosoma nearly smooth; shiny. Petiole and postpetiole more strongly microareolate and weakly areolate.

Type Material
Holotype locality. COLOMBIA: 14 workers, 1 queen, Huila, 12km W 47 Belén, Santa Leticia, Finca Merenberg, 2300m, 9-13-1-1978, rotten log in pasture (C. Kugler and J. Hahn) [1 mouthparts; 4 stings].

Paratype localities. COLOMBIA: 13 workers, 1 queen, holotype locality, , MCZ, , ; 2 workers, Huila, Las Cuevas de los Guacharos National Park, 1900-2300m, near Palestina, about 20km S Pitalito, 15-1 7-1-1978 (C. Kugler and J. Hahn) [whole specimen slide mounted] MCZ.

Etymology
This species is named in honor of Gunther Buch and his family, who have heroically maintained part of their farm, Finca Merenberg, as a nature preserve and permitted the collection of these and other ants.