Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Image catalog (click here). Includes images of holotype.
Range
Costa Rica, Panama, Venezuela, Ecuador.
Identification
Crematogaster bryophilia is uniquely characterized by the combination of (1) shiny face, (2) subquadrate dorsal face of petiole, (3) appressed tibial pilosity, (4) moderate length erect filiform setae on face, and (5) "normal" propodeal spines (as opposed to curvispinosa's spines with swollen bases).
Description of worker
Color light to dark brown, gaster darker than rest of body, mandibles straw yellow, often contrasting with darker head capsule.
Mandibles smooth and shiny; face smooth and shiny; scapes with abundant long subdecumbent setae and scattered long, erect setae; antennal club 2-segmented; anterior margin of clypeus very weakly convex; clypeus shiny with 2-4 longitudinal rugulae; face with moderately abundant, medium length setae; in full face view a few short setae projecting from posterior margin of head, none from lateral margins; ventral surface of head smooth and shiny with sparse subdecumbent pilosity. In lateral view, pronotum rises steeply, curves into weakly convex dorsal surface of promesonotum, dropping posteriorly to propodeal suture; mesonotum slightly differentiated, raised slightly relative to pronotum; dorsal and posterior faces of propodeum not differentiated, sloping evenly from mesonotum to petiolar insertion; propodeal suture impressed medially, appearing shallow in lateral view because lateral carinulae bridge suture; propodeal spines of medium length, spiniform, upturned; side of pronotum smooth and shiny; katepisternum and side of propodeum microareolate/punctate, with variable degree of smooth shiny spaces, particularly medial katepisternum and lateral propodeum; pronotal dorsum with faint microareolate sculpture overlain by weak longitudinal rugulae; mesonotum with relatively strong lateral carinulae that extend onto propodeum, medial area smooth and shining to weakly sculptured; propodeal declivity weakly areolate punctate anteriorly, grading to smooth and shiny posteriorly; invariably with pair of long flexuous setae on humeri, shorter pair on mesonotum, and seta on base of propodeal spine, variable number of additional setae may be present on promesonotum (series from Osa Peninsula with relatively abundant dorsal setae of variable length); legs with appressed pubescence, no erect setae.
Petiole in side view triangular; side with feeble to well-impressed microareolate/punctate sculpture; anteroventral tooth varying from low, obtuse angle to distinct subacute tooth; dorsal face subquadrate, longer than wide, smooth and shining; posterodorsal face short; posterolateral tubercles each with a long seta; postpetiole in dorsal view globular, or slightly wider than long with weak posterior emargination; postpetiole with small obtuse to subacute anteroventral tooth; dorsum smooth and shiny; with 4 or more erect setae; fourth abdominal tergite smooth and shiny with 20-30 long erect setae (more than 50 on series from Osa Peninsula).
Measurements:
Holotype: HL 0.505, HW 0.530, HC 0.492, SL 0.389, EL 0.114, WL 0.512, SPL 0.054, PTH 0.128, PTL 0.169, PTW 0.145, PPL 0.139, PPW 0.156, CI 105, OI 23, SI 77, PTHI 76, PTWI 86, PPI 112, SPI 11.
Other specimens: HL 0.580, 0.535, 0.635; HW 0.633, 0.584, 0.710; HC 0.572, 0.522, 0.647; SL 0.458, 0.460, 0.536; EL 0.133, 0.120, 0.158; A11L 0.236; A11W 0.108; A10L 0.102; A10W 0.097; A09L 0.042; A09W 0.065; A08L 0.038; A08W 0.058; WL 0.639, 0.570, 0.708; SPL 0.097, 0.118, 0.109; PTH 0.153, 0.125, 0.163; PTL 0.194, 0.184, 0.236; PTW 0.174, 0.142, 0.184; PPL 0.152, 0.133, 0.170; PPW 0.181, 0.138, 0.222; CI 109, 109, 112; OI 23, 22, 25; SI 79, 86, 84; PTHI 79, 68, 69; PTWI 90, 77, 78; PPI 119, 104, 131; SPI 15, 21, 15; ACI 2.39.
Description of Queen
A normal queen (dorsal face of propodeum drops steeply from postscutellum and much of propodeum appears ventral to scutellum and postscutellum); color light to dark brown, gaster darker than rest of body; mandibles smooth and shiny; face smooth and shiny; scapes with abundant long subdecumbent setae and scattered long, erect setae; terminal four segments of antenna gradually enlarged, forming club; anterior margin of clypeus flat to weakly emarginate; clypeus shiny with faint etchings laterally; face with abundant, long flexuous setae; in full face view sparse setae project from lateral and posterior margins of head posterior to eyes, none from lateral margins anterior to eyes; ventral surface of head smooth and shiny with sparse suberect pilosity; pronotal dorsum at right angle to anterior collar, short, vertical, continuous with vertical anterior face of mesonotum; moderately abundant flexuous erect setae on dorsal mesonotum and scutellum; one long seta on side of propodeum anterior to propodeal spine; propodeal spine short, triangular; femora with subdecument setae; tibia with combination of subdecument and long suberect setae; petiole similar to worker but dorsal face more tapered anteriorly, anteroventral tooth absent or a small, ventrally-directed obtuse triangle; postpetiole with no ventral tooth or a minute denticle, postpetiole subquadrate in dorsal view, posterior margin gently convex with faint medial emargination; fourth abdominal tergite smooth and shiny; postpetiole and fourth abdominal tergite with abundant erect flexuous setae.
Natural History
Crematogaster bryophilia prefers montane wet forest habitats, where it nests in mature forest canopy. It nests in dead branches but unlike most Crematogaster species also frequently nests beneath epiphyte mats. Most collections of C. bryophilia that I have observed are from the Atlantic slope of Costa Rica. At La Selva Biological Station, in lowland rainforest, it is relatively rare. It occurred in 7 of 52 canopy fogging events, and I have only once found it there by manual search (a nest was in a thin dead branch of a tall Erythrina tree [Fabaceae]). Upslope from La Selva in Braulio Carrillo National Park I collected a nest that was 20m high in a Licania tree (Chrysobalanaceae). There was a moss-covered branch and along the branch was a patch of flat, pale green lichen. Beneath this lichen patch were a single colony queen, most of the workers, and all of the brood. Workers occurred in galleries beneath the moss, extending about one half meter to each side of the lichen patch. I did not see any workers on the surface of the moss mat or on foliage. Perhaps the lichen provided an improved microhabitat, being warmer and drier than the surrounding moss. Near Turrialba I found an aggregation of workers, brood, and alate queens under a bark flap on a Psidium guajava tree (Myrtaceae) in a brushy pasture at the edge of mature forest. The workers were foraging in columns on the Psidium trunk and branches. In the Pe–as Blancas Valley east of Monteverde, a montane wet forest site at 800m elevation, I have collected the species on over five occasions. I observed one nest in a thin dead branch, several in internodes of Cecropia insignis saplings (Cecropiaceae), one in the hollow stem of a small Guarea (Meliaceae), and one under an epiphyte clump in a recently felled Licaria tree (Lauraceae). I found nests under epiphyte mats at Estacion Cacao in Guanacaste Conservation Area and at Sirena in Corcovado National Park. Nests may contain alate queens and tiny pale males. Twice I have found ergatogynes, once alone in a nest with workers, and once along with a single physogastric colony queen.
Beyond Costa Rica I have records of collections from montane areas in Panama, Venezuela, and Ecuador. The specimens from Venezuela were intercepted with orchids at a U. S. quarantine station, suggesting association with epiphytes.
This species is infrequent in collections, and most of my collections have been by discovering nests, finding workers in fresh treefalls, or finding nocturnal foragers. It is not among the species routinely found in baiting studies, sweep samples, or Malaise traps. Yet my nest collections are relatively frequent, suggesting the species can be common if you know where to look. It is a habitat and elevational specialist, perhaps a largely nocturnal forager, and perhaps doing much of its foraging under epiphytes, all factors contributing to its apparent rarity.
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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