Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
|
|
|
Image catalog (click here). Includes images of holotype.
Range
Costa Rica.
Identification
Crematogaster wardi is uniquely characterized by the combination of (1) yellow coloration; (2) humeral setae of mesosomal dorsum long, flexuous, and longer than any other mesosomal setae; (3) relatively long propodeal spines; and (4) relatively elongate promesonotum. Similar species are minutissima and flavomicrops.
Description of worker
Color yellow orange; workers monomorphic in size.
Mandibles feebly striate on proximal half, smooth and shining with large piligerous puncta on distal half; clypeus with two longitudinal carinulae at anterior margin, anterior margin gently convex to straight; head longer than wide, with rounded posterior border; antenna with terminal two segments enlarged to form a club, third segment from end somewhat enlarged, blurring distinction between two and three-segmented club; scapes with abundant suberect flexuous setae; when scapes laid back from antennal insertions, they distinctly surpass margin of vertex; face smooth and shining, with a few concentric carinulae around antennal insertion; face covered with abundant, long, erect, flexuous, white setae, no appressed pubescence; in face view setae project from lateral and posterior margins.
Promesonotum in lateral profile somewhat flattened, pronotum and anterodorsal face of mesonotum of similar length, nearly in same plane; posterior face of mesonotum short, meeting dorsal face at angle but not produced or tuberculate, dropping to propodeal suture; propodeal suture deep in dorsal view but partially obscured in profile by lateral carinulae that bridge the suture; propodeum with short, differentiated dorsal face and longer posterior face; propodeal spines medium length, spiniform, directed posteriorly and weakly curving upward; pronotal dorsum with sparse longitudinal carinulae, interspaces smooth and shining; mesonotum with parallel lateral carinae that converge toward propodeal suture; medial mesonotum concave, smooth and shining; dorsal face of propodeum feebly rugulose, posterior face smooth and shining; side of pronotum smooth and shining; katepisternum smooth and shining medially, feebly punctate at margins; side of propodeum shining, largely smooth with traces of feeble carinulae ventrally; promesonotum with long flexuous white to amber erect setae in three ranks, four across anterior pronotum, two at anterior mesonotum, and two at mesonotal midlength; humeral setae are longest (0.21mm), other six are subequal in length (0.15mm); propodeal dorsum with one or two pairs long setae, on base of propodeal spines and half way along spine shaft; short inconspicuous setae sparsely scattered elsewhere on mesosomal dorsum; tibiae with abundant short subdecumbent setae, none longer than maximum tibial width.
Petiole in side view trapezoidal, punctate; anteroventral tooth present, rounded, right-angle, or acute; dorsal face of petiole smooth and shining, subrectangular, longer than wide, with about eight long amber setae along posterior border; postpetiole with acute anteroventral tooth, postpetiole in dorsal view subquadrate, wider than long, with emarginate posterior margin, abundant long setae; fourth abdominal tergite smooth and shining, with abundant long suberect amber setae, no appressed pubescence.
Variation:
Workers vary in robustness and coloration. Small workers are relatively paler, with weaker sculpture on the katepisternum and flatter promesonotum. Large workers are darker orange, with stronger punctate sculpture on the katepisternum, and a more arched promesonotum. The two collections I have from the Osa Peninsula are small and pale. Material from La Selva Biological Station varies from small and pale to larger and darker. Three workers collected at 1070m elevation in Braulio Carrillo National Park above La Selva vary from small and pale to larger and darker orange. A series of three workers from Bajo La Hondura, an 1100m elevation site near the southeastern edge of Braulio Carrillo, are the largest I have seen, with distinctly arched promesonotum, and lacking the anterior row of long setae on the pronotum. I initially had access to only these large workers and the specimens from the Osa Peninsula, and I considered them distinct species. Subsequent collections from La Selva revealed variation linking the two forms. It is likely that there is some form of clinal variation on the Atlantic slope, with small pale forms dominating in the lowlands and larger, darker forms more common at higher elevations, a pattern seen in many other ant lineages.
Measurements:
Holotype: HL 0.537, HW 0.546, HC 0.493, SL 0.473, EL 0.156, WL 0.618, SPL 0.110, PTH 0.143, PTL 0.201, PTW 0.162, PPL 0.141, PPW 0.181, CI 102, OI 29, SI 88, PTHI 71, PTWI 81, PPI 128, SPI 18.
Other specimens: HL 0.581, 0.547, 0.669; HW 0.615, 0.554, 0.683; HC 0.570, 0.495, 0.626; SL 0.499, 0.472, 0.640; EL 0.162, 0.168, 0.186; A11L 0.241; A11W 0.128; A10L 0.105; A10W 0.111; A09L 0.054; A09W 0.086; A08L 0.046; A08W 0.059; WL 0.676, 0.626, 0.801; SPL 0.142, 0.123, 0.163; PTH 0.168, 0.138, 0.178; PTL 0.213, 0.196, 0.267; PTW 0.194, 0.159, 0.218; PPL 0.145, 0.158, 0.177; PPW 0.209, 0.180, 0.241; CI 106, 101, 102; OI 28, 31, 28; SI 86, 86, 96; PTHI 79, 70, 67; PTWI 91, 81, 82; PPI 144, 114, 136; SPI 21, 20, 20; ACI 0.80.
Natural History
Crematogaster wardi occurs in mature wet forest habitats on both the Atlantic and Pacific slopes of Costa Rica. The species is known only from workers. They have been collected three times as nocturnal foragers on low vegetation, once as diurnal foragers on extrafloral nectaries of an Inga sapling, twice in Malaise traps, and three times in Winkler samples of sifted leaf litter from the forest floor.
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
Date of this version: 4 March 2003.
Go back to top