Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Image catalog (click here).
Range
Costa Rica, Brazil (Santa Catarina).
Identification
This species shares most of the characters of crinosa relatives (face with sparse erect setae over short appressed pubescence, sparse erect setae on mesosomal dorsum, short upturned propodeal spines) but differs in the presence of long flexuous rather than short stiff setae on the mesosomal dorsum. Similar Costa Rican species are crinosa, torosa, rochai, and erecta. The flexuous dorsal setae differentiate it from the first three. Crematogaster erecta has flexuous setae on the pronotal humeri but the other dorsal setae are short and stiff. Also, erecta has a general habitus difference: the propodeal spines are a bit thinner and longer and the size polymorphism less pronounced.
Description of worker (Costa Rica)
Color red brown, gaster darker.
In face view head subquadrate, about as wide as long, with emarginate posterior margin; mandibles shiny, smooth or with faint striae; clypeus convex, smooth and shiny; scapes falling short or just attaining posterior margin of head when laid back from insertions; terminal three to four segments of antenna gradually lengthening and broadening, becoming increasingly densely pubescent, terminal two segments very much larger than proximal segments, so that antennal club appears two-segmented; scapes with abundant long subdecumbent to suberect pubescence, with no differentiated long erect setae; face with abundant long subdecumbent to suberect pubescence, 1-5 medium length filiform erect setae on face posterior to frontal carinae; malar spaces and space between eyes and antennal insertions with fine longitudinal striae, rest of face smooth and shining.
Promesonotal profile forming a single convexity, mesonotum slightly elevated posteriorly, dropping abruptly to propodeal suture (not elevated, sloping gradually to suture in Braulio Carrillo worker); propodeal suture deep in dorsal view but not visible in lateral view due to lateral carinulae that bridge the suture, these carinulae with small denticle (carinulae reduced and lacking denticle on Braulio Carrillo worker, such that propodeal suture more v-shaped in lateral view); dorsal and posterior faces of propodeum in same plane, sloping from propodeal suture to petiolar insertion, anterior half of face faintly and irregularly punctatorugose, becoming smooth and concave posteriorly; propodeal spines upturned, medium length, narrowly acute and spiniform; promesonotal dorsum with weak sculpture, usually with more or less longitudinally oriented rugulae or striae, interspaces smooth and shining; side of pronotum faintly striate anteriorly, becoming smooth and shining posteriorly; katepisternum punctatorugose (punctate on Braulio Carrillo specimen), sublucid; side of propodeum faintly longitudinally striate or etched ventrally, smooth dorsally; promesonotal dorsum with 7-11 medium length flexuous setae, those on pronotal humeri longest; anterodorsal propodeum with 0-1 erect flexuous setae; femora and tibiae with abundant subdecumbent pubescence, no erect setae.
Petiole in lateral view subtrapezoidal, sublucid, with faint microsculpture; anteroventral petiolar tooth strongly developed, triangular, acute, with blunt tip (tooth smaller on Braulio Carrillo worker); dorsal face of propodeum smooth and shiny, subquadrate, about as wide as long, sides flat to somewhat convex, widest point of petiole about midlength; posterolateral tubercles each with an erect posteriorly directed seta; postpetiole with small sharp ventral denticle (lacking on Braulio Carrillo worker), globular to subquadrate in dorsal view, about as long as wide, posterior margin rounded to emarginate, with 2-8 erect setae; fourth abdominal tergite smooth and shining, with sparse subdecumbent to suberect pubescence and abundant long erect setae that are evenly distributed across tergite, erect setae stiffer than those on mesosoma.
Measurements:
HL 0.908, 0.702, 0.921; HW 0.996, 0.812, 1.031; HC 0.933, 0.738, 0.989; SL 0.710, 0.570, 0.709; EL 0.174, 0.172, 0.170; A11L 0.303; A11W 0.136; A10L 0.125; A10W 0.120; A09L 0.082; A09W 0.090; A08L 0.074; A08W 0.078; WL 0.993, 0.786, 1.038; SPL 0.138, 0.102, 0.153; PTH 0.208, 0.179, 0.224; PTL 0.243, 0.180, 0.266; PTW 0.238, 0.196, 0.209; PPL 0.201, 0.161, 0.229; PPW 0.233, 0.203, 0.255; CI 110, 116, 112; OI 19, 25, 18; SI 78, 81, 77; PTHI 86, 99, 84; PTWI 98, 109, 79; PPI 116, 126, 111; SPI 14, 13, 15; ACI 0.75.
Description of Queen (Costa Rica)
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.
Natural History
Crematogaster moelleri inhabits montane moist to wet forest habitats in Costa Rica. It is known from few collections. In the Monteverde community area, near the continental divide in the Cordillera de Tilar‡n, I observed workers foraging on a tree trunk in a garden area. Suzanne Koptur collected workers twice from extrafloral nectaries of Inga trees. At 1000m elevation on the Atlantic slope of the Cordillera Volcanica Central, in the Zona Protectora of Braulio Carrillo National Park, the ALAS project collected workers in one Malaise trap and an alate queen in another.
Comments
When I observed moelleri in the field in Monteverde it looked and acted like typical crinosa group species such as crinosa or torosa, but workers moved very slowly. I noted at the time that it was odd to see a crinosa group colony at an elevation as high as Monteverde, where I had never seen crinosa group species before. I assumed it was torosa or one of the other common species at the upper edge of its elevational range, but on laboratory examination I was surprised to find a morphologically distinct form. The additional Koptur samples from Monteverde and the ALAS collections from another montane site reinforced its distinctness from lowland forms. Thus it appears to be a low density species that occurs in a narrow elevational band, in wet to moist forests just above the typical range of the abundant lowland forms in the crinosa group.
The type locality of moelleri is Santa Catarina State in southern Brazil. I examined the MHNG syntypes of moelleri long before seeing the Costa Rican material, and made these notes:
"This series is similar to crinosa but has erecta tendencies. The pilosity is very like erecta, with long flexuous hairs on head and humeri, hairs on fourth abdominal tergite long but stiff, underlying pubescence long and suberect. The scapes are relatively short, like crinosa, failing to reach vertex margin. The propodeal spine is short and upturned, more like crinosa than erecta. Strong petiolar tooth. Variable in size (more like crinosa) and red-brown color (fading due to age, or more reddish in life?). There are the faintest traces of metanotal tooth where the carinae extend onto propodeum (also present on some crinosa.) Overall, most like a very hairy crinosa."This matches closely the above description from Costa Rican material. It remains to be seen whether the concordance in morphology represents convergence due to shared environmental conditions or shared phylogenetic history.
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
Date of this version: 4 March 2003.
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