Proceratium catio

AntWiki: The Ants --- Online
Proceratium catio
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Proceratiinae
Tribe: Proceratiini
Genus: Proceratium
Species: P. catio
Binomial name
Proceratium catio
De Andrade, 2003

Proceratium catio P casent0178756.jpg

Proceratium catio D casent0178756.jpg

Specimen Label

Workers have been collected from the leaf litter of tropical rainforest.


A member of the micrommatum clade. catio is the sister species of Proceratium brasiliense (q. v.) but differs from it, in the worker and gyne, by the petiole 1/5 longer than broad instead of at most 1/8 longer than broad, by the postpetiole shorter than 1/2 of the length of the gastral tergite I (LT4) instead of slightly longer and by the postpetiole and gaster, both more convex than in brasiliense. (Baroni Urbani and de Andrade 2003)

Keys including this Species


Known from Colombia, Ecuador and Venezuela.

Latitudinal Distribution Pattern

Latitudinal Range: 4.816° to 4.816°.

Tropical South

Distribution based on Regional Taxon Lists

Neotropical Region: Colombia (type locality), Venezuela.

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.

  • catio. Proceratium catio De Andrade, in Baroni Urbani & De Andrade, 2003b: 135, figs. 62 - 64 (w.) COLOMBIA.
    • Type-material: holotype worker.
    • Type-locality: Colombia: Valle, Bosque El Ensueño, K 27 Via mar, 1700m., (P. Chacón).
    • Type-depository: LACM.
    • Status as species: Sosa-Calvo & Longino, 2008: 231; Escárraga, Longino & Sosa-Calvo, 2019: 688.
    • Distribution: Colombia.

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



Head longer than broad, with subparallel sides. Vertex in full face view convex. Clypeus corresponding to a small triangular tooth between the antennal socket. 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 and diverging posteriorly. Genal carinae strongly marked. Sulcus between the genal carinae and the gular area impressed. Eyes composed by a clearly convex facet slightly 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 7-10. Mandibles with 5-6 denticles before the apical tooth. Palp formula 3,2.

Mesosoma slightly elongate. Promesopleural and mesometapleural sutures impressed on the ventral half only. Basal face of the propodeum with a high medial tumulus; area behind the propodeal tuinulus short, resembling a transversal sulcus with the postero-lateral border carinate. Declivous lace of the propodeum flat, the sides crenulate and sub-convex close to the propodeal lobes. Propodeal lobes truncate. Propodeal spiracles tumuliform.

Petiole longer than broad, subparallel in the anterior fourth and convex posteriorly in dorsal view. Anterior border of the petiole straight, strongly carinate and slightly denticulate on each side. Ventral process of the petiole very small and sub-triangular. Postpetiole shorter than 1/2 of the gastral tergite I (LT4), with the sides strongly convex in dorsal view. Postpetiolar dorsum with a median, short tumulus close to the posterior border. Postpetiolar sternite anteromedially with a marked, subround projection. Posterior half of the postpetiolar sternite slightly convex. Constriction between postpetiole and gastral segment I strongly impressed. Gastral tergite I convex dorsally and round on the curvature. Gastral sternite I (LS4) very short medially, carinate and slightly protruding anteriorly on the sides. Remaining gastral tergites and sternites curved ventrally.

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

Sculpture. Head granulopunctate and irregularly rugulose. Mesosoma granulate, with short, irregular rugae and with sparse, very irregular, superficial foveae. Petiole and postpetiole granulate-foveolate, the granulation raised to form small peaks and the foveae deeper than on the mesosoma. Anterior half of the gaster smooth and with rare, small granulation. Posterior half of the gaster with strong, dense granules.

Body covered by hairs of three main types: (1) short, dense, subdecumbent on the whole body, very dense on the tumulus of the basal face of the propodeum, sparse and erect on the funicular joints; (2) long, erect or suberect and slightly dense on the whole body, absent from the tumulus of the basal face of the propodeum and on the antennae, slightly longer on the petiole, postpetiole and on the gaster; (3) shorter than hair type (1), dense, subdecumbent or appressed 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 with slightly lighter antennae and legs.

Measurements in mm and Indices: TL 3.38; HL 0.79; HW 0.68; EL 0.06; SL 0.49; WL 0.91; PeL 0.36; PeW 0.29; HFeL 0.60; HTiL 0.50; HBaL 0.37; LS4 0.14; LT4 0.78; CI 86.1 ; SI 62.0; IGR 0.18.


(tentative attribution). Differing from the worker in the following details: eyes large, about 1/4 of the head length and with interocellar pilosity. Ocelli well developed. Funicular joints 2-10 slightly broader than long. Mandibles with 5-6 denticles before the apical tooth.

Mesosoma robust and convex in profile. Parapsidal furrows marked. Scutellum convex. Metanotum without tooth or spine-like projection. Basal face of the propodeum short and separate from the declivous face by a carina more marked and sub-angulate laterally.

Fore wings of our type 4, hind wings of our type 3 as defined in the description of the genus.

Sculpture. Rugosities on the mesosoma weakly arranged longitudinally. Mesosoma and scutellum without foveae.

Pilosity as in the worker except for the hair type (2) slightly shorter, rare on the basal face of the propodeum.

Colour light ferrugineous.

Measurements in mm and Indices: TL 3.40-4.03; HL 0.73-0.87; HW 0.62-0.74; EL 0.18-0.21; SL 0.45-0.55; WL; PeL 0.34-0.39; PeW 0.28-0.31; HFeL 0.56-0.71; HTiL 0.45-0.58; HBaL 0.32-0.45; LS4 0.16-0.20; LT4 0.85-0.98; CI 84.9-85.0; SI 61.6-63.2; IGR 0.19-0.20.

Type Material

Holotype worker (unique) from Colombia labelled: "Valle, Bosque El Ensueno, K 27 Via mar, 1700 m, 5.VI. 2000, 1 worker, P. Chacon", deposited in the Los Angeles County Museum of Natural History.


This species is named after the Catios, the former inhabitants of this part of Colombia.


Baroni Urbani, C., de Andrade, M.L. 2003. The ant genus Proceratium in the extant and fossil record (Hymenoptera: Formicidae). Museo Regionale di Scienze Naturali, Monografie, 36, 1–492. (page 135, figs. 62-64 worker, queen described)