Crematogaster carinata

This is a wide ranging, variable ant. It may in fact be a complex of closely related species that may prove to be ecological distinct as opposed to having clearly separable morphological differences. In some areas C. carinata (see details in the biology section below) they form sprawling, polygynous colonies while in other parts of their range they can be found in what may be co-evolved parabiotic associations with other ant species.

Identification
Longino (2003) - Costa Rican species in the limata complex are Crematogaster brasiliensis, Crematogaster carinata, Crematogaster limata, and Crematogaster tenuicula. All have abundant erect flexuous setae on the face, moderate length to short posteriorly directed propodeal spines, 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 carinata has a squared-off anteroventral petiolar process and no postpetiolar process. Both brasiliensis and tenuicula have ventral postpetiolar processes. Crematogaster limata usually lacks a petiolar process but can be very like carinata in some cases. Crematogaster limata is a larger ant with longer propodeal spines. Crematogaster carinata may also be confused with Crematogaster foliocrypta, but foliocrypta has appressed rather than erect tibial pilosity.

Within carinata, there is pronounced variation in the degree of anterior narrowing of the petiole in side view, strength of pronotal carinulae, size of propodeal spines, and some details of queen size and petiole shape. Crematogaster levior is more likely to be a “good” species, in terms of phylogeny and/or genetic similarity. Crematogaster carinata, with its greater geographic range and morphological variability, is more likely to be a set of allopatric or parapatric species, or even a set of broadly sympatric cryptic species.

Crematogaster carinata is also very similar to the South American species Crematogaster levior. The two species are not cleanly separable on morphological grounds. In this revision I have restricted C. levior to a specialized parabiotic associate of Camponotus femoratus. Crematogaster levior and Camponotus femoratus inhabit ant gardens throughout Amazonian South America. All Crematogaster material collected from these ant gardens has the worker pronotum completely smooth and shining. In contrast, I have identified as carinata all material with longitudinal carinulae on the pronotum. However, on purely morphological grounds there is continuous variation from strongly carinate forms, to forms with faint traces of carinulae, to the completely smooth pronotum of levior. Crematogaster levior is polygynous and polydomous like some populations of carinata. Crematogaster levior is always parabiotic with Camponotus femoratus, while C. carinata is facultatively parabiotic with other large ants in the genera Dolichoderus and Odontomachus.

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

Biology
De Oliveira et al. (2015), studying ant occupancy of Cecropia trees in southwest Bahia, Brazil, found a colony of  opportunistically nesting in a Cecropia pachystachya tree. Gillette et al. (2015) in a Chaipas, Mexico field study of twig-nesting ants in coffee plants found C. carinata nesting within one sampled plot of plants at 500m.

Nomenclature

 *  carinata. Crematogaster carinata Mayr, 1862: 768 (w.) BRAZIL. Longino, 2003a: 46 (q.). Combination in C. (Orthocrema): Emery, 1922e: 136. Senior synonym of parabiotica: Longino, 2003a: 44.
 * parabiotica. Crematogaster limata r. parabiotica Forel, 1904e: 683 (w.) COLOMBIA. Forel, 1912f: 217 (q.). Combination in C. (Orthocrema): Emery, 1922e: 136. Raised to species: Wheeler, W.M. 1921b: 99 (in text); Wheeler, W.M. & Darlington, 1930: 109. Subspecies of limata: Wheeler, W.M. 1921f: 152; Wheeler, W.M. 1923a: 3; Kutter, 1931a: 61; Santschi, 1939f: 161; Kempf, 1972a: 88. Junior synonym of carinata: Longino, 2003a: 44.

Worker
Longino (2003) - HL 0.561, 0.528, 0.657; HW 0.604, 0.563, 0.722; HC 0.565, 0.507, 0.664; SL 0.485, 0.512, 0.612; EL 0.130, 0.139, 0.175; A11L 0.215; A11W 0.101; A10L 0.113; A10W 0.089; A09L 0.068; A09W 0.064; A08L 0.051; A08W 0.051; WL 0.615, 0.585, 0.744; SPL 0.077, 0.109, 0.148; PTH 0.148, 0.137, 0.166; PTL 0.207, 0.213, 0.250; PTW 0.144, 0.138, 0.174; PPL 0.169, 0.129, 0.178; PPW 0.162, 0.119, 0.166; CI 108, 107, 110; OI 23, 26, 27; SI 86, 97, 93; PTHI 71, 64, 66; PTWI 70, 65, 70; PPI 96, 92, 93; SPI 13, 19, 20; ACI 0.64.

Color red brown; mandibles, antennal club, and tarsi usually lighter yellow; workers monomorphic in size.

Mandibles smooth and shining; clypeus usually with 5-6 longitudinal carinulae, these may be more abundant, making clypeus uniformly striate, or they may be nearly absent, making clypeus smooth and shining, especially medially; head about as long as wide, subquadrate, with emarginate posterior border; antenna with distinct two-segmented club, or 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 slightly 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 forming evenly convex surface, varying from flattish to forming peak at juncture of pro and mesonotum; propodeal suture deep in dorsal view but obscured in profile due to lateral carinulae that bridge the suture; posterior mesonotum curves smoothly into horizontal dorsal face of propodeum; propodeal spines short, projecting posteriorly such that they are more or less in same plane as dorsal face of propodeum; dorsal and posterior face of propodeum appear well differentiated in lateral view, the dorsal face confluent with the horizontal spines, the posterior face sloping down to petiolar insertion, but faces less differentiated medially; pronotal dorsum with variably developed longitudinal carinulae, strongest laterally, becoming weaker medially, interspaces smooth and shining; mesonotal dorsum with two strong, subparallel lateral carinae, interspace smooth and shining or with faint longitudinal carinulae; dorsal face of propodeum striatorugose, rugulae extending onto spines, posterior face smooth and shining; side of pronotum smooth and shining; katepisternum and ventral portion of side of propodeum variously punctatorugose; dorsal portion of side of propodeum smooth and shining; 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 subtrapezoidal, varying in length and degree of narrowing anteriorly, weakly punctate to nearly smooth; anteroventral tooth well developed, often forming a right-angle to short acute tooth; dorsal face of petiole smooth and shining, elongate, widest posteriorly, regularly tapering anteriorly, with a long flexuous seta on each posterolateral tubercle and varying number of short setae along posterior border; postpetiole lacking ventral 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, Rio de Janeiro (Novara), (examined, NMW worker here designated LECTOTYPE).