Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
Image catalogue, worker (click here).
Image catalogue, worker, sem (click here).
Bolivia, Brazil (Amazonas, Bahia, Goi‡s, Par‡, Pernambuco), Colombia, Costa Rica, Ecuador, Guyana, Panama, Peru, Trinidad, Venezuela. Costa Rica: Atlantic slope. Range maps (South America) (Costa Rica).
Description of worker
Worker measurements (n=1, Costa Rica): HW 0.90, HL 0.90, SL 0.58, EL 0.27, MeL 1.13, MeW 0.64, PrW 0.52, PrL 0.27, PrS 0.21, PrT 0.48, MTL 0.57, MFL 0.66, MFW 0.21, PtL 0.32, PtW 0.29, PpW 0.40, PtH 0.29, AL 1.13, AW 0.96, ASW 0.022.
Head roughly circular in outline; frontal carina closely appressed to torulus, in the form of a thin raised line where it passes over dorsum of torulus and onto clypeus; face to vertex margin with shallow, irregular foveae; interspaces between foveae of variable width, from thin lines to as wide as foveae, with fine granular sculpture; interiors of foveae with fine areolate etchings, not smooth and shining; clypeus bent ventrad at level of antennal insertions; clypeus longitudinally rugose, with prominent median ruga and 2-3 rugae on each side, these variably developed and sometimes absent; genae with closely-spaced foveae; genal bridge longitudinally rugose; mandible with coarse longitudinal striae to relatively smooth with a granular surface; eyes weakly convex, slightly skewed ventrad; scape flattened with thick lateral margin distally, becoming narrower and more terete basally, then flaring into a basal flange; margin of vertex angulate, weakly crenate; vertex with some coarse striae radiating from the occiput, otherwise smooth and shiny.
In dorsal view, mesonotum with small weakly elevated, subacute teeth; propodeal suture a broad, shallow trough, not breaking sculpture; dorsal face of propodeum with anterolateral lobes distinct, subrectangular, with variably developed posterolateral angle; pronotum foveate; mesonotum and dorsal face of propodeum with continuous longitudinal striae; posterior face of propodeum perpendicular to dorsal face, slightly concave; completely smooth and shining; parallel longitudinal striae cover lateral pronotum, anepisternum, katepisternum, and lateral propodeum; forecoxae smooth, hindcoxae striate; hind femur strongly swollen medially, spindle-shaped; posterior surface of forefemur smooth; outer surface of metatibia largely smooth and shiny, with a few faint rugae.
Ventral margin of petiole flat, lacking anteroventral tooth, or at most with a weak tubercle; anterodorsal face of petiole smooth and shining or transversely rugose; posterodorsal face longitudinally rugose; postpetiole with a long, gently sloping anterior face, a broad, rounded summit near the posterior margin, and a steeply sloping posterior face; ventral margin of postpetiole short, with a prominent, acute anterior tooth; dorsal surface of postpetiole longitudinally rugose; first gastral tergite sculpture highly variable, from uniformly punctate to smooth, and from non-striate to regularly longitudinally striate (figure) (see Comments); anterolateral portion of first gastral sternite with oblique longitudinal striae, these fading medially and posteriorly; remainder of sternite smooth with microreticulate sculpture; second gastral tergite longitudinally striate.
Short, stiff setae uniformly distributed on disc of face and mesosomal dorsum; about 20 on disc of face, about 0.05mm long; somewhat longer stiff setae on petiole, postpetiole, and anterior portion of first gastral tergite; setae on first gastral tergite erect, clustered near postpetiolar insertion, becoming sparser and shorter posteriorly; appressed pubescence on first gastral tergite extremely short and sparse; color largely black, with contrasting orange scapes and tibiae.
Description of queen (based on queen from Brazil, Pernambuco: Recife, LACM ENT 140153):
Queen measurements: HW 1.023, HL 0.991, SL 0.670, EL 0.352, MeL 1.565, MeW 0.919, MTL 0.704, MFL 0.772, MFW 0.278, PtL 0.422, PtW 0.335, PpW 0.478, PtH 0.345, AL 1.461, AW 1.142, ASW 0.027.
Similar in most respect to worker; face with deeper, more discrete foveae than on worker, intervals subequal to fovea diameter medially, more closely spaced laterally; intervals opaque, sericeous; pronotum evenly foveate like face, but foveae deeper; mesoscutum, axillae, and scutellum with elongate foveae and raised, subsericeous, longitudinal intervals; dorsal face of propodeum longitudinally striate. See also Kempf (1951:42).
Procryptocerus pictipes has been collected from wet forest areas, typically as workers from low vegetation, canopy, or recent treefalls. One nest series was collected in Venezuela, from a dead twig in a treefall. The species is relatively common in canopy fogging samples from La Selva Biological Station in Costa Rica.
Types and Synonymy
Procryptocerus pictipes Emery 1896:98. Holotype worker: Costa Rica, Suerre, near Jimenez [MCSN]. Kempf 1951:42 (description of nontype worker and queen from Guyana).
Procryptocerus striatus scabriusculus var. parva Menozzi 1935:196 (unavailable name). Syntype worker(s): British Guiana, Kuruduni River (identification by Kempf 1951:42).
Comments (phylogenetic and biogeographic scenario)
The sculpture on the first gastral tergite varies geographically, as follows: 1) Central America and Ecuador: distinctly striate; striae moderately regular; underlying micropunctate sculpture weak, giving somewhat shiny appearance; 2) Amazonian Peru, Bolivia: striae pronounced and regular; underlying micropunctate sculpture strong, giving granular appearance; 3) central Amazonian region to coast, Guyana, Venezuela: striae weak, poorly organized; micropunctate sculpture strong, giving granular appearance; 4) two isolated specimens, Colombia, R’o Porce, and Brazil, Goi‡s, Jata’: striae and micropunctate sculpture both nearly effaced. The R’o Porce specimen is shinier than the Jata’ specimen. The former appears derived from typical Central American stock, while the latter appears derived from Amazonian stock. Striae are nearly always visible at the posterior border, even when largely effaced elsewhere. Sculpture on the second gastral tergite varies on small spatial scales (e.g., within Costa Rica). The tergite is often uniformly striate, but striae may be effaced medially or entirely.
Species with which P. pictipes is phenetically similar are P. belti, P. hirsutus, P. convexus, and P. lepidus. One specimen (Brazil, MT: Sinop, 12ˇ31'S 55ˇ37'W, Dec. 1974 [M. Alvarenga] [MZSP]), as yet unidentified and probably a new species, shares characters of P. belti and P. convexus. The face is shallowly areolate, like P. convexus. The frontal carinae are closely appressed to the torulus and the clypeus is not at all produced, like P. convexus and P. pictipes. The first gastral tergite is densely micropunctate, with abundant long erect and decumbent setae, like P. belti. The entire promesonotum is irregularly foveate, like P. belti.
A phylogenetic hypothesis leads from P. rudis-group species to P. belti/hirsutus to the Sinop specimen to P. convexus and finally to P. pictipes. In this series, one can see the gradual evolution of foveate facial sculpture, starting with the pronounced clathrate sculpture of the P. rudis-group. In this scenario, the high clathrate sculpture and elevated frontal carinae are plesiomorphic. Speciation produces P. belti, with character shifts toward smaller size, dense punctate sculpture on the first gastral tergite, and dense erect and appressed setae on the first gastral tergite. As the lineage spreads from a Central American or Andean origin into the Amazon, it becomes larger and develops longitudinal striae on the mesonotum. This is P. hirsutus, parapatric with P. belti. Somewhere within the range of P. belti/hirsutus, speciation produces a new form in which the frontal carinae become closely appressed to the dorsum of the torulus, resulting in a somewhat shorter clypeus, and the clathrate face sculpture becomes very shallow. This is the specimen from Sinop. This new lineage is capable of coexisting with the P. belti/hirsutus lineage. As it spreads, it loses the dense setae on the gaster, leaving only sparse erect setae, clustered near the postpetiolar insertion. One form loses the punctate sculpture, and becomes P. convexus. Another form develops the beginning of facial foveae. The polygons of the shallow clathrate sculpture become more rounded, as the walls thicken, and the floors of the foveae lose the shininess and develop microareolate sculpture. Also, the punctation on the first gastral tergite begins to align and incipient striae are formed. This form, P. pictipes, is very successful and spreads throughout the Amazon and into the Andes and up to Costa Rica. As it moves, the first gastral tergite becomes more regularly striate, and the underlying punctation weakens.
It may be that P. convexus and the Sinop form represent peripheral populations that speciated through allopatry, generating P. pictipes, which then spread northward and westward. This would follow the traditional view of speciation occurring at the edges of ranges. Alternatively, we could be seeing the results of "centripetal speciation" of Brown, in which successive waves of new forms spread from the center. Procryptocerus pictipes may be the newest lineage, spreading and displacing earlier P. pictipes-like forms. The Sinop form and P. convexus would then represent ancestral forms, previously with larger ranges, and now occurring as relicts at the edges of the range of P. pictipes.
The relationship with P. lepidus is unclear. Procryptocerus lepidus occurs in southeastern Brazil, and may be a parapatric version of P. pictipes. One series (Brazil: Minas Gerais: Lavras, 20 Oct 1978 [W. D. Fronk] [MCZC]), appears intermediate between P. pictipes and P. lepidus. This series has the first gastral tergite striate and punctate, much like Bolivian and eastern Peruvian P. pictipes, but the face sculpture is more linearly arranged rather than foveate.
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. email@example.com
Date of this version: 6 December 2002.
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