Proceratium convexiceps

AntWiki: The Ants --- Online
Proceratium convexiceps
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Proceratiinae
Tribe: Proceratiini
Genus: Proceratium
Species: P. convexiceps
Binomial name
Proceratium convexiceps
Borgmeier, 1957

Nothing is known about the biology of Proceratium convexiceps.


A member of the micrommatum clade, resembling Proceratium mexicanum, but differing from it, in the worker, by the area between basal and declivous faces of the propodeum with at most a faint, lateral, transversal carina instead of well marked, in the gyne, by the area between basal and declivous faces of the propodeum weakly angulate instead of carinate and angulate, and in the worker and gyne by deeper body sculpture. (Baroni Urbani and de Andrade 2003)

Keys including this Species


Known from Costa Rica, Guatemala, Mexico, Nicaragua and Panama.

Latitudinal Distribution Pattern

Latitudinal Range: 19.38111111° to -0.146944°.

Tropical South

Distribution based on Regional Taxon Lists

Neotropical Region: Costa Rica (type locality), Guatemala, Mexico, Panama.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.


Explore-icon.png Explore Overview of Proceratium biology 
Very little is known about the biology of Proceratium ants. They nest in soil, rotten wood, under deep-set stones and, in a few cases, tree branches. For many species the nest consists of small rounded chambers hollowed out of soft rotten wood or in the soil. Toward the cooler limits of the range, particularly in North America, nests and foraging workers are found under deep set rocks instead of in rotten wood. The nest site is usually in forest shade, in old moist gardens, or similar habitats that are constantly moist. Some species of known to be egg predators of arthropods, especially of spiders.

Most Proceratium are relatively rare but this is not the full explanation for why they are not commonly collected. Colonies of most species are small. Based on anectdotal natural history information from a few species, it was once thought that most Proceratium would likely be found to have mature colonies that contain somewhere between 10 - 50 workers. Yet nests with more than 50, and in some cases up to 200, workers have been been reported. Besides small colonies, these ants also do not appear to forage in places where they are readily encountered.

Males and females are though to be produced in small numbers but we generally do not have enough data for colonies of any species to know what might be typical. Reproductive flights have been observered toward the end of the summer in some northern temperate areas. In these regions the nuptial flight occurs during the last half of August. Both sexes climb some distance from the nest entrance before taking flight. Workers too issue from the nest during the nuptial flight, as is often the case with otherwise cryptobiotic ants. ‎



The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • convexiceps. Proceratium convexiceps Borgmeier, 1957: 120, figs. 34, 35 (w.) COSTA RICA.
    • Type-material: holotype worker.
    • Type-locality: Costa Rica: San José (H. Schmidt).
    • Type-depository: MCZC.
    • Baroni Urbani & De Andrade, 2003b: 149 (q. putative m.).
    • Junior synonym of micrommatum: Brown, 1980b: 342; Brandão, 1991: 373; Bolton, 1995b: 366.
    • Status as species: Brown, 1958g: 247; Snelling, R.R. 1967: 9 (in key); Kempf, 1972a: 211; Baroni Urbani & De Andrade, 2003b: 145 (redescription); Fernandes, Delabie & Fernández, 2019: 554.
    • Distribution: Costa Rica, Mexico, Panama.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.



Baroni Urbani and de Andrade (2003) - Head longer than broad, slightly narrower anteriorly than posteriorly. Vertex in full face view straight or gently convex. Clypeus very reduced medially, subtriangular, between and much shorter than the antennal sockets. Antennal socket with broad torulus. Frontal carinae close to each other, not covering the antennal insertions. Frontal area behind the frontal carinae weakly convex. Lateral expansions of the frontal carinae relatively narrow, raised, gently convex or subparallel. Genal carinae present and well marked. A superficial sulcus between the genal carinae and the gular area. Eyes present, composed by a clearly convex facet below the midline of the head. Scapes thicker in the distal half and far short of the vertexal margin. First funicular joint 1/3 longer than broad. Funicular joints 2-10 broader than long. Last funicular joint as long as the sum of joints 6-10. Mandibles with 3-4 denticles before the apical tooth. Palp formula 3,2.

Mesosoma convex in profile. Promesonotal and propodeal sutures absent. Promesopleural and mesometapleural sutures impressed on the ventral half only. Basal face of the propodeum gently declivous and with traces of a superficial, transversal sulcus close to the declivous face; the sulcus without or with traces of a faint, postero-lateral carina. Declivous face of the propodeum with the sides superficially marginate, the margin variably crenulate. Propodeal lobes subround and with variably crenulate margin. Propodeal spiracles small and tumuliform.

Petiole slightly longer than broad. Petiole in dorsal view with the sides subparallel in the anterior fifth and convex posteriorly. Anterior border of the petiole gently concave and carinate. Ventral process of the petiole subtriangular and small. Postpetiole about 1/2 of the length of the gaslral tergite I (LT4). Postpetiole in dorsal view anterolaterally subround and with convex sides. Postpetiolar dorsum with a tumulus close to the posterior border. Postpetiolar sternite anteromedially with a marked subtriangular projection. Posterior half of the postpetiolar sternite straight or slightly convex. Constriction between postpetiole and gaslral segment I deeply impressed. Gastral tergite I strongly convex on the curvature. Gastral sternite I very short medially. Sides of gastral sternite I obtuse and protruding anteriorly. Remaining gastral tergites and sternites curved ventrally.

Legs moderately elongate. Mid tibiae without spur. Spurs of fore legs without basal spine. Fore basitarsi longer than the mid ones. Hind basitarsi about 1/5 or 1/4 shorter than the hind tibiae. Second tarsomere of mid and hind legs longer than the third and fourth tarsomeres and slightly shorter than pretarsus. Pretarsal claws simple. Arolia small.

Sculpture. Head, mesosoma, petiole and postpetiole reticulate-punctate and granulate, the granules sparse on the head and mesosoma, denser and larger on the petiole and postpetiole. Mesosoma, petiole and postpetiole with additional foveae, superficial, sparse and small on the mesosoma, deeper and denser on the petiole and postpetiole. First gastral tergite smooth and with minute, sparse piligerous punctures, the punctures denser, larger and mixed with reticulation on its sides and posterior border. Legs and antennae superficially granulate-punctate.

Body covered by hairs of three main types: (1) short, dense, subdecumbent on the whole body, sparse and suberect on the funicular joints; (2) long, suberect and relatively dense on the whole body, slightly shorter on the head, absent from the antennae; (3) shorter than hair type (1), dense, decumbent on the funicular joints only. In addition the funicular joints bear whitish, thick, appressed, short, sparse hairs, and the scapes with sparse hairs similar to type (2) but shorter.

Colour dark ferrugineous or dark brown with antennae and legs lighter.

Measurements in mm and Indices: TL 3.04-3.58; HL 0.69-0.80; HW 0.63-0.70; EL 0.05-0.07; SL 0.43-0.56; WL 0.81-0.96; PeL 0.32-0.39; PeW 0.25-0.32; HFeL 0.52-0.67; HTiL 0.44-0.56; HBaL 0.28-0.44; LS4 0.13-0.14; LT4 0.73-0.87; CI 87.5-91.5; SI 60.5-70.0; IGR 0.16-0.18.


Baroni Urbani and de Andrade (2003) - Differing from the worker in the following details: eyes larger, less than 113 of the head length and with ocular pilosity. Ocelli well developed. Mesosoma robust and convex in side view. Parapsidal furrows weakly marked. Scutellum with the sides converging posteriorly and with the posterior border rounded. Metanotum without tooth or spine-like projection. Basal face of the propodeum very short, laterally weakly angulate, medially incised and as flat as the declivous face.

Petiole longer than broad.

Measurements in mm and Indices: TL 3.47; HL 0.72; HW 0.67; EL 0.20; SL 0.45; WL 1.00; HFeL 0.58; HTiL 0.49; HBaL 0.34; LS4 0.15; LT4 0.89; GI 91.8; SI 61.6; IGR 0.17.


Baroni Urbani and de Andrade (2003) - (tentative attribution). Head slightly longer than broad. Vertex in full face view convex. Vertexal margin weakly carinate. Clypeus medially extremely reduced, subround, between and about as long as the antennal sockets. Antenna1 socket with broad torulus. Frontal carinae thin, low, diverging posteriorly and separated from each other. Anterior half of the frons gently convex and with a variably impressed longitudinal ridge, posterior half concave. Ocelli very large. Compound eyes slightly less than 1/2 of the head length, placed largely on the anterior head sides and with interocellar pilosity. Scapes reaching the pair ocelli or slightly surpassing them (in the specimen from Tempisque). First funicular joint thicker than the second joint and slightly broader than 1/2 of its length. Funicular joints 2-11 about 1/2 longer than broad. Last funicular joint about as long as the sum of joints 9-1 1. Mandibles elongate, edentate, only with a single, pointed apical tooth. Palp formula 3,2.

Mesosoma robust. Pronotum perpendicular to the mesonotum. Mesonotum convex. Parapsidal furrows marked. Scutellum as high as the mesonotum and in full dorsal view with round posterior border. Propodeum in side view gently convex or sloping posteriorly, basal and declivous faces of the propodeum not clearly separated. Metanotum without a median spine-like projection. Propodeal lobes small and subround. Propodeal spiracles small and slightly oriented downwards.

Petiole in profile declivous on the anterior third and convex on the two posterior thirds. Petiole in dorsal view with parallel sides in the anterior third, the remaining two posterior thirds gently convex anteriorly and parallel posteriorly. Anterior border of the petiole concave and superficially carinate. Subpetiolar process in form of a narrow, subtriangular, longitudinal lamella. Postpetiole weakly convex in side view. Postpetiole anteriorly slightly broader or about as broad as the petiole; postpeliolar sides diverging and gently convex posteriorly. Anterior border of the postpetiolar sternite without a projecting triangular "lip". Gastral tergite I round. Gastral sternite I broad in thc middle. Remaining gastral tergites and sternites curved ventrally.

Legs elongate. Wind basitarsi about as long as the hind tibiae.

Fore wings of our type 5, hind wings of our types 2 and 3 as defined in the description of the genus.

Sculpture. Head, pronotum, mesonotum, pro- and mesopleurae, and scutellum variably granulate and with rare, thin, rugosities, the granulation sparse on the dorsum of the pronotum and mesonotum and larger on the scutellum. Propodeurn with dense impressions resembling irregular foveae. Metapleurae with thick, irregular rugosities. Petiole granulate-rugulose on the anterior third and on the whole sides, its dorsum more smooth. Postpetiole and first gastraI lergite with minute piligerous foveae and with granulation on their sides, the granulation rarer and smaller on the sides of the gaster. Legs minutely punctate.

Body covered essentially by hairs of three main types: (1) short, dense, subdecumbent on the whole body; (2) long, suberect and relatively dense on the whole body, slightly longer on the petiole, postpetiole and gaster; (3) shorter than hair type (1), dense, decumbent on the funicular joints. In addition the funicular joints bear whitish, thick, appressed, short, sparse hairs, the scapes and the funicular joints with hairs similar to type (1) but longer.

Colour. Dark brown to black.

Measurements in mm and Indices: TL 3.36-3.78; HL 0.56-0.63; HW 0.54-0.59; EL 0.26-0.29; SL 0.42-0.52; WL 1 .10-1.20; PeL 0.39-0.44; PeW 0.22-0.28; HFeL 0.73-0.88; HTiL 0.55-0.68; HBaL 0.54-0.66; LS4 0.25-0.30; LT4 0.73-0.92; CI 93.1-96.5; SI 75.0-82.5; IGR 0.32-0.35.

Type Material

Baroni Urbani and de Andrade (2003) - Type locality: San Jose, Costa Rica. Type material: holotype worker labelled: "San Jose, C. Rica, H. Schmidt, typus, Museum of Comparative Zoology, H-type, 29766, det. Borgmeier", in MCZC, examined.


References based on Global Ant Biodiversity Informatics

  • Baroni Urbani C., and M.L de Andrade. 2003. The ant genus Proceratium in the extant and fossil record (Hymenoptera: Formicidae). Museo Regionale di Scienze Naturali, Monografie 36: 1-480.
  • Borgmeier T. 1957. Myrmecologische Studien, I. Anais da Academia Brasileira de Ciencias 29: 103-128.
  • Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology
  • Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
  • Longino J. T. 2013. Ants of Nicargua. Consulted on 18 Jan 2013.
  • Longino J. T. L., and M. G. Branstetter. 2018. The truncated bell: an enigmatic but pervasive elevational diversity pattern in Middle American ants. Ecography 41: 1-12.
  • Longino J. T., and R. K. Colwell. 2011. Density compensation, species composition, and richness of ants on a neotropical elevational gradient. Ecosphere 2(3): 16pp.
  • Longino J. et al. ADMAC project. Accessed on March 24th 2017 at
  • Patrick M., D. Fowler, R. R. Dunn, and N. J. Sanders. 2012. Effects of Treefall Gap Disturbances on Ant Assemblages in a Tropical Montane Cloud Forest. Biotropica 44(4): 472–478.