Crematogaster abstinens

Crematogaster abstinens occurs in wet or dry forest habitats, but is more common in the latter. I have never collected this species myself and have no first-hand knowledge of its biology. It has been taking by sweeping on Barro Colorado Island, and by sweeping at night in Brazil (Mato Grosso). Ward collected ground foragers in Bolivia. (Longino 2003)

Identification
This is a wide ranging, variable species. See notes in the nomenclature section below.

Longino (2003) - The combination of (1) shiny face, (2) subquadrate dorsal face of petiole, (3) appressed tibial pilosity, (4) very wide postpetiole, and (5) abundant short stiff setae on face that curve toward the median axis uniquely characterize this species. Crematogaster obscurata is somewhat similar but has a punctate face.

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Bolivia, Brazil, Colombia, Costa Rica, French Guiana, Guyana, Mexico, Panama, Venezuela.

Nomenclature

 *  abstinens. Crematogaster abstinens Forel, 1899c: 85 (w.) PANAMA. Combination in C. (Orthocrema): Emery, 1922e: 133. Senior synonym of chacoana, erici, ornatipilis, suturalis: Longino, 2003a: 30.
 * suturalis. Crematogaster abstinens var. suturalis Forel, 1912f: 216 (w.) VENEZUELA. Combination in C. (Orthocrema): Emery, 1922e: 133. Junior synonym of abstinens: Longino, 2003a: 30.
 * ornatipilis. Crematogaster ornatipilis Wheeler, W.M. 1918b: 25 (w.) GUYANA. Combination in C. (Orthocrema): Emery, 1922e: 135. Junior synonym of abstinens: Longino, 2003a: 30.
 * erici. Crematogaster (Orthocrema) quadriformis st. erici Santschi, 1929d: 291 (w.) ARGENTINA. Junior synonym of abstinens: Longino, 2003a: 30.
 * chacoana. Crematogaster (Orthocrema) abstinens st. chacoana Santschi, 1933e: 111, fig. 6 (w.) ARGENTINA. Junior synonym of abstinens: Longino, 2003a: 30.

Longino (2003) - I was able to compare directly the types of abstinens, Crematogaster pygmaea, and Crematogaster suturalis with material that Bill and Emma Mackay collected in Colombia. They were all essentially identical. I examined the types of Wheeler's Crematogaster ornatipilis prior to having additional material for comparison, but my notes and drawings are a close match to the Colombian material, and Wheeler himself considered the species close to abstinens. The Bolivian material that I have for current examination was collected by Phil Ward after my examination of the types of Crematogaster chacoana and Crematogaster erici, both from Argentina. My museum notes for chacoana and erici describe specimens that were more robust and more heavily punctate than abstinens from northern South America, thus matching the Bolivian specimens. Until more is known of character variation in South America, I am treating the more punctate forms as geographic variants of a broadly defined polytypic abstinens.

Quinet, Hamidi, et al. (2009) - Crematogaster pygmaea, revived from synonymy.

Worker
Longino (2003) - HL 0.561, 0.519, 0.648; HW 0.630, 0.567, 0.740; HC 0.594, 0.535, 0.700; SL 0.424, 0.398, 0.503; EL 0.152, 0.149, 0.201; A11L 0.217; A11W 0.102; A10L 0.094; A10W 0.092; A09L 0.048; A09W 0.072; A08L 0.041; A08W 0.057; WL 0.620, 0.570, 0.782; SPL 0.109, 0.100, 0.139; PTH 0.123, 0.114, 0.151; PTL 0.154, 0.187, 0.282; PTW 0.207, 0.177, 0.256; PPL 0.137, 0.126, 0.160; PPW 0.208, 0.175, 0.260; CI 112, 109, 114; OI 27, 29, 31; SI 76, 77, 78; PTHI 80, 61, 54; PTWI 134, 95, 91; PPI 152, 139, 163; SPI 18, 18, 18; ACI 1.02.

Color red brown.

Head subquadrate, flattened to weakly emarginate posteriorly; mandibles shiny, smooth, with coarse elongate piligerous puncta; face smooth and highly polished medially, punctate on malar space and between antennal insertion and eye, with a few concentric rugulae around antennal insertion; scapes with abundant long subdecumbent pubescence, lacking differentiated long, erect setae; antennal club 2-segmented; anterior border of clypeus shallowly convex; clypeus shiny, smooth medially, with longitudinal rugulae laterally; face with dense stubble of 40-50 short, flattened, amber setae; face setae distinctly curved or slanted toward median axis; ventral surface of head smooth and shiny with sparse suberect to subdecumbent pilosity.

In lateral view, dorsal profile of pronotum, mesonotum, and propodeum forming a continuous curve; dorsal and posterior faces of propodeum in same plane, sloping to petiolar insertion; propodeal spines projecting posterodorsally; propodeal spiracle relatively large; pronotal dorsum largely smooth and shining with faint longitudinal carinulae; mesonotal dorsum with weak, longitudinal carinulae laterally, smooth and shiny medially; propodeal suture strongly impressed medially but less visible in side view because lateral mesonotal carinulae continue onto dorsal face of propodeum; mesonotal carinulae usually have slight tooth at propodeal suture; long flat posterodorsal face of propodeum punctate anteriorly, smooth and shiny posteriorly; propodeal spines short, thin, and sharp; side of pronotum and dorsolateral propodeum smooth and shining; katepisternum and ventrolateral propodeum punctate; promesonotum with about 15 straight, stiff setae of subequal length, those on humeri longest, approximately 0.17 mm long; propodeal spine with one seta at base, subequal in length to spine; legs with sparse, appressed to subdecumbent pilosity and no erect setae.

Petiole in side view trapezoidal; side densely punctate; lacking anteroventral tooth or angle; dorsal face short, wider than long, with convex sides, widest at midlength, faintly microareolate or smooth and shining; posterolateral tubercles low, not at all elevated above posterodorsal margin of tergite, each with a long, stiff seta; postpetiole in dorsal view much wider than long, with slight posterior emargination; anterolateral margins of postpetiolar node dropping abruptly to short, cylindrical neck of helcium; ventral margin of postpetiole with small rounded lobe, lacking sharp anteroventral tooth; dorsum and sides of postpetiole with microareolate sculpture and with 6-8 stiff setae; fourth abdominal tergite with very faint, areolate microsculpture, shiny, with about 50 stiff erect setae evenly dispersed over surface.

A Bolivian collection is generally more robust and more heavily sculptured. The mandibles are striate rather than smooth, the face punctation extends posteriorly along medial border of eye, and the mesosoma is generally more punctate throughout.

Type Material
Longino (2003) - Crematogaster abstinens Forel 1899:85. Syntype worker: Panama, Peña Blanca (Champion) [label: V. de Chiriquí, 2-3000ft, Champion] (examined).