Crematogaster brasiliensis

A species of lowland wet and moist forest. Crematogaster brasiliensis are ominivores and their foragers may be encountered any time of the day or night.

Identification
Longino (2003) - The most striking variation is in worker size polymorphism. In South America various degrees of size polymorphism occur, and collections from Amazonian Brazil can be strongly polymorphic. The small workers are similar to specimens from Central America, while the large workers have heads wider than long, the scapes do not surpass the vertex margin, and the mesonotum is produced dorsally, projecting above the pronotum.

Other morphological characters vary discordantly across the range. The petiole in side view is relatively long and low in Central America, becoming shorter in South America. Specimens from South America often have longer propodeal spines, the spines may be somewhat elevated, and the dorsal face of the propodeum may be longer and more differentiated from the posterior face.

Species in the limata complex (brasiliensis, Crematogaster carinata, Crematogaster limata, and Crematogaster tenuicula in Costa Rica) all have abundant erect flexuous setae on the face, moderate length to short propodeal spines that are directed posteriorly, and elongate tapering petioles. The four species can be difficult to separate. They differ primarily in the nature of the ventral processes of the petiole and postpetiole. Crematogaster brasiliensis has distinct anteroventral processes on both the petiole and postpetiole. Crematogaster limata and carinata lack postpetiolar processes. In Costa Rica, brasiliensis and tenuicula are relatively distinct because tenuicula lacks an anteroventral petiolar process and the petiole is higher and more triangular in side view. These two species converge and become more difficult to distinguish in South America. Crematogaster brasiliensis may also be confused with Crematogaster foliocrypta, but foliocrypta has appressed rather than erect tibial pilosity.

Distribution
Nicaragua to Amazonian Brazil, Bolivia. (Longino 2003)

Distribution based on Regional Taxon Lists
Neotropical Region: Bolivia, Brazil, Colombia, Costa Rica, Ecuador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Peru, Trinidad and Tobago.

Biology
Longino (2003) - This species prefers lowland wet to moist forest habitats, and may occur in mature forest or second growth vegetation. In Costa Rica and other northern Neotropical sites that I have visited, two other limata group species,  limata and carinata, are usually much more abundant. For example, at La Selva Biological Station in Costa Rica, carinata, limata, and brasiliensis occurred in 24, 11, and 4 fogging events, respectively, out of a total of 52 (Longino et al. 2002).

Foragers may be encountered during the day or at night. They are generalized omnivores, recruiting to protein or carbohydrate baits and visiting extrafloral nectaries.

The species is a generalized cavity nester, most often nesting in dead branches or dead vine stems that are lodged in low vegetation. It may also nest occasionally in live stems and in myrmecophytes such as Cordia nodosa and Triplaris, but its nesting in these cavities appears to be opportunistic rather than any specialized preference. Workers may build small amounts of thin, brittle carton that cover or restrict nest entrances. Colonies may be polydomous, and aggregations of workers and brood may be found in ephemeral cavities such as beneath aroid leaves appressed to trunks and beneath bark flaps. Most often nests contain only workers and brood, but I have twice found nests with workers, brood, and a single physogastric queen, suggesting monogyny.

One of these nests was in an elongate scar on the trunk of a small understory tree (Erythrochiton lindenii, Rutaceae). The scar was covered with thin, brittle, mud-like carton. I found one physogastric queen among the workers and brood, and a thorough search did not reveal any other reproductives.

Another nest was in a live stem of a large-stemmed shrub in the Asteraceae. The trailside herb had stems that had been extensively hollowed out by a stem-boring lepidopteran larva, and one of the stems had been cut by machete, leaving a 13mm diameter, exposed, necrotic end. A brasiliensis nest occupied the cavity in this cut stem, and the workers had constructed a carton baffle over the cut end. The large lumen was almost completely closed by carton, except for a small entrance hole just large enough for workers.

Colonies may be subject to parasitism by Microdon (Syrphidae). One nest I collected at La Selva Biological Station contained three large Microdon larvae in addition to workers and brood.

Nomenclature

 *  brasiliensis. Crematogaster brasiliensis Mayr, 1878: 875 (w.) BRAZIL. Forel, 1912f: 217 (q.). Combination in C. (Orthocrema): Emery, 1922e: 136. Senior synonym of armandi, cocciphila, inca, ludio: Longino, 2003a: 37. Current subspecies: nominal plus arawak.
 * ludio. Crematogaster limata r. ludio Forel, 1912f: 217 (w.) BRAZIL. Wheeler, W.M. 1921f: 151 (q.). Combination in C. (Orthocrema): Emery, 1922e: 136. Subspecies of brasiliensis: Forel, 1913l: 233. Junior synonym of brasiliensis: Longino, 2003a: 37.
 * armandi. Crematogaster armandi Forel, 1921a: 208 (w.q.) BRAZIL. Combination in C. (Orthocrema): Kempf, 1972a: 84. Junior synonym of brasiliensis: Longino, 2003a: 37.
 * inca. Crematogaster (Eucrema) inca Wheeler, W.M. 1925a: 27 (w.) PERU. Junior synonym of brasiliensis: Longino, 2003a: 37.
 * cocciphila. Crematogaster (Orthocrema) brasiliensis var. cocciphila Borgmeier, 1934: 102 (w.q.) SURINAM. Junior synonym of brasiliensis: Longino, 2003a: 37.

Worker
Longino (2003) - HL 0.646, 0.601, 0.897; HW 0.713, 0.642, 1.026; HC 0.665, 0.594, 0.995; SL 0.657, 0.622, 0.798; EL 0.165, 0.163, 0.207; A11L 0.284; A11W 0.118; A10L 0.149; A10W 0.086; A09L 0.074; A09W 0.057; A08L 0.067; A08W 0.044; WL 0.740, 0.723, 1.092; SPL 0.151, 0.135, 0.198; PTH 0.140, 0.125, 0.227; PTL 0.248, 0.264, 0.354; PTW 0.170, 0.154, 0.259; PPL 0.186, 0.133, 0.215; PPW 0.168, 0.145, 0.248; CI 110, 107, 114; OI 26, 27, 23; SI 102, 103, 89; PTHI 56, 47, 64; PTWI 69, 58, 73; PPI 90, 109, 115; SPI 20, 19, 18; ACI 1.61.

Color red brown; workers monomorphic in size.

Mandibles smooth and shining; clypeus varying from feebly striate, with 5 or more longitudinal carinulae, to nearly smooth and shining; head about as long as wide, subquadrate, with broadly convex sides and flat to weakly emarginate posterior border; antenna with terminal two segments enlarged to form a club, third segment from end somewhat enlarged, blurring distinction between two and three-segmented club; scapes with abundant long erect setae; when scapes laid back from antennal insertions, they surpass margin of vertex; face largely smooth and shining, with variable extent of striated region between antennal insertion and eye, and whorled above antennal insertion; face covered with abundant long flexuous white setae, no appressed pubescence; in face view abundant setae project from lateral and posterior margins.

Promesonotum in profile somewhat flattened dorsally, short anterior face of pronotum rises to dorsal face, dorsal faces of pronotum and mesonotum subequal in length, horizontal, forming single flat surface or meeting at a slightly produced angle, dorsal and posterior faces of mesonotum meeting at distinct angle, posterior face dropping to propodeal suture; propodeal suture deep in dorsal view but obscured in profile due to lateral carinulae that bridge the suture; lateral carinulae often with minute triangular tooth at propodeal suture; propodeal spines medium length, projecting posteriorly; in lateral view propodeum appears to have distinct dorsal and posterior faces because profile is horizontal from propodeal suture onto propodeal spines, but medially there is a single declivity from propodeal suture to petiolar insertion; pronotal dorsum with variably developed longitudinal carinulae, strongest laterally, becoming weaker medially, interspaces smooth and shining, in some cases almost entirely smooth and shining with no carinulae; anterodorsal face of mesonotum with weak, subparallel lateral carinae, these continue onto posterodorsal face as stronger carinae that converge posteriorly, interspace concave, smooth and shining; propodeal declivity smooth and shining; side of pronotum smooth and shining; katepisternum weakly to distinctly punctate or punctatorugose; side of propodeum very faintly sculptured; mesosomal dorsum with abundant long flexuous white setae, setae on pronotal humeri longest; femora and tibiae with abundant long erect setae.

Petiole in side view elongate, trapezoidal, weakly punctate to nearly smooth; anteroventral margin with a short right angle to somewhat rounded tooth; posterior ring-like aperture that receives postpetiole large, dorsal margin at nearly same level as posterolateral lobes of dorsal face when petiole viewed in profile with ventral margin horizontal (in contrast to tenuicula, in which posterior aperture is smaller and posterolateral lobes of dorsal face are distinctly higher than dorsal margin of aperture); dorsal face of petiole smooth and shining, elongate, widest posteriorly, regularly tapering anteriorly, with long flexuous setae along posterior border; postpetiole with distinct, subacute, short anteroventral tooth, globular in dorsal view, with abundant erect setae; fourth abdominal tergite smooth and shining, with abundant long flexuous erect white setae, no appressed pubescence.

Queen
Longino (2003) - A normal queen (dorsal face of propodeum drops steeply from postscutellum and much of propodeum appears ventral to scutellum and postscutellum) with general shape, sculpture, and pilosity characters of the worker; size characters as in Figures.

Type Material
Longino (2003) - Syntype workers: Brazil, Pará, Prainha, 1°48'S 53°29'W, on Tococa guianensis Aubl. (Trail #5); Brazil, Amazonas, Barcelos, 0°58'S 62°57'W, on Clidemia tococoidea (DC.) Gleason (Trail #27) [type data from Benson and Setz 1985] (examined, Trail #5 worker here designated LECTOTYPE).