Procryptocerus scabriusculus Forel 1899

Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker lateral view

worker face view

Image catalogue, worker (click here).

Image catalogue, worker, sem (click here).


Mexico to Venezuela. Range Map.

Description of worker

Worker measurements (n=1, Costa Rica): HW 1.286, HL 1.163, SL 0.768, EL 0.306, MeL 1.503, MeW 0.955, PrW 0.679, PrL 0.307, PrS 0.298, PrT 0.606, MTL 0.827, MFL 0.911, MFW 0.339, PtL 0.434, PtW 0.431, PpW 0.549, PtH 0.395, AL 1.459, AW 1.173, ASW 0.018.

Head subcircular; vertex flat, sharply differentiated from face by vertex margin, which is entire and somewhat crenate; face evenly convex; in lateral view anterior portion of clypeus curves ventrad, more strongly curved than general curvature of face and posterior clypeus; frontal carina thickened and laterally flattened just posterior to torulus, ending on dorsum of torulus; vertex shiny, with thin, widely spaced, somewhat irregular, and at times nearly absent longitudinal rugae (Central America, Colombia), or with dense, regular, pronounced longitudinal striae (Venezuela); face sculpture dominated by irregular shallow striae, with foveae not clearly formed and, if present, relatively large (Central America), or striae on the face thickened and nearly fused, isolating smaller, well-formed, teardrop-shaped foveae, and the areolate microsculpture more pronounced, giving the face a granular, less shiny appearance (Colombia, Venezuela); clypeus irregularly longitudinally striate with a few arcing transverse striae at anterior border; genae foveate; mandibles coarsely longitudinally striate; undersurface of head longitudinally striate; scapes with a flanged skirt at base, partially covering neck and condyle; scape weakly flattened, curving and gradually widening distally; scape finely and superficially microareolate dorsally, coarsely rugose on anterior edge; eyes in anterior view convex, asymmetrically skewed ventrally.

Promesonotum in dorsal view with rounded anterior margin, straight to weakly convex sides which converge to base of propodeum; humeri forming obtuse to subacute angles; lateral lobes of mesonotum not or only weakly elevated or projecting, usually approximating right angles aligned with the body axis; anterior border of pronotum with row of coarse foveae, rest of promesonotum and dorsal face of propodeum longitudinally striate; dorsal face of propodeum with produced lateral lobes which extend about half to two thirds the length of the dorsal face; lateral lobes rounded posteriorly; propodeal spines generally subequal in length to dorsal face, but varying from shorter to longer; dorsal face of propodeum curving into approximately perpendicular posterior face, dorsal striae extend about half way down posterior face, rest smooth and shining; in lateral view promesonotum evenly convex; propodeal suture shallow; sides of pronotum flat, meeting dorsal face at distinct angle; lateral face pronotum, anepisternum, katepisternum, and lower portion of lateral face of propodeum with coarse longitudinal striae; femora strongly swollen, spindle-shaped; exterior surfaces of tibiae coarsely rugose; posterior face of forefemur smooth and shining or weakly striate.

Petiole short and squat, anterior face coarsely transversely rugose (smooth in some Mexican specimens); posterior face and dorsum of postpetiole irregularly longitudinally striate; first gastral tergite longitudinally striate throughout; interspaces microareolate, giving a subopaque or granular appearance to gaster; longitudinal striae usually do not or only weakly extend onto second gastral tergite; first gastral sternite subopaque to somewhat shiny with uniformly distributed small puncta, grading to patches of longitudinal rugulae or striae anterolaterally.

Face, dorsum of mesosoma, petiole, postpetiole, and gaster with sparse, short, erect to suberect setae; setae relatively longer and more abundant on petiole, postpetiole, and anterior portion of gaster; setae stiff but not strongly flattened.

The worker is also thoroughly described by Kempf (1951).

Description of queen:

Queen measurements (n=1, Costa Rica, LACM ENT 140413): HW 1.205, HL 1.146, SL 0.742, EL 0.392, MeL 1.943, MeW 1.104, MTL 0.867, MFL 0.973, MFW 0.308, PtL 0.512, PtW 0.443, PpW 0.585, PtH 0.431, AL 1.709, AW 1.335.

Similar to worker in most respects; face relatively more foveate and less distinctly striate; foveae relatively large and nearly confluent in Mexican specimens, smaller and interspaces more stria-like in Costa Rican specimens, foveae very small and interspaces smooth with microareolate sculpture in Colombian specimens; pronotum coarsely foveate; mesoscutum, axillae, and scutellum with elongate foveae; dorsal face of propodeum longitudinally to obliquely striate.

See Kempf (1951) for a full description.

Natural History

Procryptocerus scabriusculus is a frequently encountered species of Procryptocerus in Central America. Unlike most species, P. scabriusculus is most often found in dry habitats, roadsides, and second growth vegetation. Nest sites appear to be ephemeral, mostly in dead stems (records include stems of Acacia, Spilanthes and Baccharis trinerva), although nests have been found in live stems. A Creighton collection from Mexico was "in Cecropia," presumably an opportunistic occurrence in a sapling. Many of the specimens at USNM were on orchid plants intercepted by inspectors at U.S. entry ports. The orchids were most often Oncidium and Cattleya, but this probably reflects the preferences of orchid enthusiasts rather than the preferences of P. scabriusculus. Skwarra (1934) describes five colonies, three of which were in dead wood, one in hollow twigs, and one in a reed (from Kempf 1951). The following data are extracted from field notes and specimen labels.

Ojo de Agua (Longino): remnant moist forest patch. Two monogynous nests were collected from the tips of vertical dead sticks. One stick also contained an additional lone queen in a chamber immediately below the nest.

Longino #2621: polygynous colony (three queens) in live branch of recent treefall.

Ward #6515: roadside vegetation, ex dead stalk of Spilanthes.

Ward #7816: roadside, ex dead weed stalk.

Ward #7822: roadside, ex dead twig Baccharis trinervis.

Wilson's Finca (Janzen): secondary forest, ex twig.

In quarantine from Guatemala, ex Oncidium wentworthianum, ex orchids.

Ward #3757: cloud forest, ex dead twig of woody liana.

Ward #7431: second growth rainforest, ex dead twig.

Ward #7349-3, #7349-4: rainforest edge, queens and males at light.

Xilitla (Creighton): in Acacia twig.

Ciudad del Maiz (Creighton): in Cecropia.

Ward #8915: thorn woodland, ex dead twig Ficus.

Ward #8933, #8949, #8953: three nests ex dead twigs.

In quarantine from Caracas, ex Cattleya mossiae.

Wheeler (1984) observed the behavioral repertoire of a captive colony of P. scabriusculus, and used the results to discuss the phylogenetic significance of behavioral traits within the Cephalotini. The study took place in central Costa Rica, and in the course of the study four colonies were examined. At least one of the colonies was polydomous, in a cluster of twigs from a Spondias tree, and three colonies were polygynous, with up to 27% of the adult population composed of queens. I have observed both monogynous nests and one polygynous nest (with 3 dealate queens) near Monteverde, Costa Rica.

Workers forage at dusk and/or nocturnally, queens and males occur at lights at night, and sexuals have been observed leaving the nest at night (Snelling 1968).

Types and Synonymy

Procryptocerus adlerzi: Emery (nec Mayr) 1890:55 (misidentified worker: Costa Rica, Palmares).

Procryptocerus striatus schmalzi var. scabriusculus Emery, 1894:198. Holotype worker: Costa Rica, Palmares (Alfaro) [MCSN] (unavailable quadrinomial).

Procryptocerus striatus scabriusculus: Forel, 1899:45 (first available use).

Procryptocerus scabriusculus: Kempf 1951:89; Snelling 1968:1 (description of male).


Multiple collections from each region reveal little within-region variation, and the shared characters (face sculpture for Venezuela and Colombia, vertex sculpture for Colombia and Central America) are quite consistent. Whether these are three allopatric lineages, or points along a continuum of geographic variation, is unknown. A possible phylogeny is (Central America (Colombia, Venezuela), with the face sculpture common to Colombia and Venezuela being apomorphic, and the vertex sculpture in Venezuela being autapomorphic.

The male is thoroughly described by Snelling (1968).

Literature Cited

Page author:

John T. Longino, The Evergreen State College, Olympia WA 98505 USA.

Date of this version: 6 December 2002.

Previous versions of this page: 7 November 1997.
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