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Species: Crematogaster evallans   Forel, 1907 


Classification:
Download Data

See Also:

Crematogaster evallans carbonescens, Crematogaster evallans evallans

Taxonomic History (provided by Barry Bolton, 2017)

Crematogaster evallans Forel, 1907h PDF: 6 (footnote) (w., not q. as stated) BRAZIL. Neotropic. AntCat AntWiki HOL

Taxonomic history

Forel, 1912g PDF: 218 (w.).
Senior synonym of Crematogaster carbonescens: Longino, 2003A PDF: 66.

Distribution:


Neotropical Region: Brazil, Colombia, Costa Rica, Espírito Santo, Guatemala, Huila, Magdalena, Puntarenas, Retalhuleu, Rio de Janeiro, Valle

Distribution Notes:

Costa Rica, Colombia, Brazil (Espirito Santo, Rio de Janeiro).

Biology:

Natural History:

Crematogaster evallans is found in wet forest habitats. Like other relatives of C. acuta, it appears to have large colonies that are at low density and infrequently encountered. In Costa Rica I have observed it several times in Corcovado and Manuel Antonio national parks, usually as a rapid column of workers descending a tree and fanning out onto the ground or low vegetation. In one case I saw worn trails in the moss on a tree trunk, suggesting a large colony with regularly used trunk trails. I have seen only one nest, which was at a site near Santa Marta in Colombia, along a road edge. Multiple dead branches were lodged in a vine tangle about 4m high in a small tree. A large colony occupied all the dead branches. The branches had been hollowed out by termites, and abandoned termite carton filled the interiors. Workers and alate queens were thinly scattered throughout the branches. There were few large aggregations of workers, and few of the nests contained any brood. There was no obvious colony center, and it is likely that these branches contained only part of a much larger colony that occurred higher in the tree. The nests contained numerous inquiline beetles and at least one silverfish (Atelurinae).

Nothing is known of colony founding, but queens exhibit a morphology often associated with social parasitism.

Taxonomic Treatment (provided by Plazi)

Treatment Citation: Longino, J. T., 2003, The Crematogaster (Hymenoptera, Formicidae, Myrmicinae) of Costa Rica., Zootaxa 151, pp. 1-150

Crematogaster evallans ForelHNS 1907

Crematogaster evallans ForelHNS, 1907b:6 (footnote). Syntype workers: Rio de Janeiro (Naegeli) [MHNG, MCSN] (examined, MHNG worker here designated LECTOTYPE). Emery, 1922:137: combination in C. (Eucrema)HNS.

Crematogaster evallans var. carbonescens ForelHNS, 19131:233. Syntype workers: Brazil, Espirito Santo (von Ihering No. 16795) [MHNG] (examined). Emery, 1922:137: combination in C. (Eucrema)HNS. NEW SYNONYMY

Range

Costa Rica, Colombia, Brazil (Espirito Santo, Rio de Janeiro).

Description of worker

Color dark red brown to black.

Head subquadrate, posterior margin emarginate, with compound eyes projecting beyond lateral margins in full face view; mandibles striate; clypeus emarginate anteriorly, convex, with faint microareolate surface sculpture and widely spaced weak rugulae that converge anteromedially; face punctate over much of surface, with variably developed anteromedian strip on face smooth and shiny; scape surface etched, subopaque; scape with abundant erect setae, setae as long as width of scape or greater; antennal club not well defined, terminal 3-5 segments gradually lengthening and becoming increasingly densely pubescent, often appearing distinctly 3-segmented; face with abundant long erect fine whitish setae, both on dorsal surface and projecting from sides; malar spaces and ventral surface of head with abundant short erect to suberect setae.

In lateral view, dorsal profile of promesonotum moderately convex, mesonotum differentiated from pronotum, projecting and forming elevated anterior boss; propodeal suture a deep crease medially, visible in dorsal view, but thin lateral carinulae bridge suture, such that in lateral view suture appears broad, shallowly impressed; dorsal and posterior faces of propodeum not well differentiated, together in nearly the same plane as mesonotal dorsum; propodeal spines thin, long, sharp; side of pronotum evenly punctate and medially impressed; anepisternum and katepisternum evenly punctate; side of propodeum faintly microareolate to smooth and shining, always with much weaker sculpture than side of pronotum and katepisternum; promesonotal dorsum uniformly punctate, sometimes overlaying faint traces of clathrate rugae; dorsal and posterior faces of propodeum faintly microareolate, often fading to smooth and shiny posteriorly; promesonotum and dorsal face of propodeum with abundant long whitish setae; legs with combination of abundant suberect and decumbent setae.

Petiole in side view subtriangular, uniformly punctate; anteroventral tooth a shallow, obtuse gibbosity, not produced or angulate; dorsal face rectangular, about twice as long as wide, smooth and shiny on anterior two thirds, grading to faintly microaerolate posteriorly; postpetiole with short, blunt ventral tooth, postpetiole in dorsal view subquadrate, wider than long, with longitudinal median sulcus, posterior margin emarginate; anterolateral margin nearly perpendicular to stem of helcium, node of postpetiole separated from helcium by a distinct sulcus; fourth abdominal tergite with faint microareolate sculpture; abundant erect long whitish setae on posterodorsal petiole, postpetiole, and fourth abdominal tergite.

Measurements

HL 0.686, 0.634, 0.667; HW 0.742, 0.686, 0.693; HC 0.688, 0.631, 0.662; SL 0.664, 0.624, 0.655; EL 0.170, 0.152, 0.152; A11L 0.279; A11W 0.116; A10L 0.133; A10W 0.101; A09L 0.090; A09W 0.075; A08L 0.058; A08W 0.063; WL 0.791, 0.731, 0.758; SPL 0.202, 0.185, 0.188; PTH 0.193, 0.178, 0.182; PTL 0.277, 0.231, 0.241; PTW 0.213, 0.199, 0.195; PPL 0.198, 0.185, 0.189; PPW 0.292, 0.251, 0.254; CI 108, 108, 104; OI 25, 24, 23; SI 97, 98, 98; PTHI 70, 77, 76; PTWI 77, 86, 81; PPI 147, 136, 134; SPI 26, 25, 25; ACI 0.14.

Queen

In lateral profile dorsal face of propodeum sloping obliquely from postscutellum, such that most of propodeum is posterior to scutellum (in contrast to normal queens, in which dorsal face of propodeum drops steeply from postscutellum and much of propodeum appears ventral to scutellum and postscutellum, Fig. 1); entire body, including scape, mandible, face, mesosoma, petiole, postpetiole, and fourth abdominal tergite smooth and shiny; propodeal spines long, acute; petiole and postpetiole robust, generally similar to worker in shape but completely lacking anteroventral petiolar tooth of any kind, and petiole relatively shorter, dorsal face only slightly longer than broad; appendages, dorsal surfaces of head, mesosoma, and postpetiole, and posterodorsal surface of petiole with abundant erect whitish setae; queens from Colombia, Dept. Magdalena relatively less pilose, with setae very sparse on fourth abdominal tergite; queens from Dept. Huila much more pilose, almost lanose over entire body, including fourth abdominal tergite; also, queens from Dept. Magdalena have relatively larger heads then queens from Dept. Huila; size characters as in Figures 4 and 5.

Biology

Crematogaster evallansHNS is found in wet forest habitats. Like other relatives of C. acutaHNS, it appears to have large colonies that are at low density and infrequently encountered. In Costa Rica I have observed it several times in Corcovado and Manuel Antonio national parks, usually as a rapid column of workers descending a tree and fanning out onto the ground or low vegetation. In one case I saw worn trails in the moss on a tree trunk, suggesting a large colony with regularly used trunk trails. I have seen only one nest, which was at a site near Santa Marta in Colombia, along a road edge. Multiple dead branches were lodged in a vine tangle about 4m high in a small tree. A large colony occupied all the dead branches. The branches had been hollowed out by termites, and abandoned termite carton filled the interiors. Workers and alate queens were thinly scattered throughout the branches. There were few large aggregations of workers, and few of the nests contained any brood. There was no obvious colony center, and it is likely that these branches contained only part of a much larger colony that occurred higher in the tree. The nests contained numerous inquiline beetles and at least one silverfish ( Atelurinae).

Nothing is known of colony founding, but queens exhibit a morphology often associated with social parasitism (see Natural History Overview).

Comments

Crematogaster evallansHNS and the similar species C. acutaHNS share a unique combination of characters: largely punctate face, erect tibial pilosity, and abundant clear to whitish (not amber, as in arcuataHNS) long erect setae on the face and mesosomal dorsum. The two species may be distinguished by several characters (see Key), but perhaps the most discrete is the acute ventral postpetiolar tooth on acutaHNS, contrasted with a bluntly rounded lobe on evallansHNS.

Specimen Habitat Summary

Found most commonly in these habitats: 1 times found in disturbed road edge forest, 1 times found in tropical wet forest, 2 times found in wet forest, 1 times found in Canga (= savanna on iron outcrops), 1 times found in lowland rainforest, 1 times found in rainforest.

Found most commonly in these microhabitats: 1 times in dead branches, 2 times Workers scattered over vegetation; a column ascending a tree trunk to the canopy., 1 times column on understory vegetation, 1 times understory vegetation, 1 times on low vegetation.

Collected most commonly using these methods: 2 times search.

Elevations: collected from 5 - 975 meters, 73 meters average

Type specimens: Lectotype Crematogaster evallans: jtl055944; Lectotype of Crematogaster evallans: casent0908444; syntype carbonescens: jtl055875; syntype evallans: jtl027848; syntype of Crematogaster evallans: casent0902146; syntype of Crematogaster evallans carbonescens: casent0908445; syntypes evallans: jtl055945



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