Proceratium toschii

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Proceratium toschii
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Proceratiinae
Tribe: Proceratiini
Genus: Proceratium
Species: P. toschii
Binomial name
Proceratium toschii
(Consani, 1951)

Proceratium-toschii hal.jpg

Nothing is known about the biology of Proceratium toschii.


A member of the toschii clade. Differing from its sister species, Proceratium terroni, in the worker, by the presence of suberect, long hairs on the head and on the mesosoma. Both species share a similar general body shape. (Baroni Urbani and de Andrade 2003)

Keys including this Species


Distribution based on Regional Taxon Lists

Afrotropical Region: Kenya (type locality).

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.

  • toschii. Sysphincta toschii Consani, 1951: 167, fig. 1 (w.) KENYA.
    • Type-material: holotype worker.
    • [Note: Baroni Urbani & De Andrade, 2003b: 282, point out that the holotype is a “sub-ergatoid gyne”, not a worker.]
    • Type-locality: Kenya: Nairobi, ix.1945 (S. Patrizi).
    • Type-depository: EZGT.
    • [Note: in the publication the holotype is said to be in IEUB, but Baroni Urbani & De Andrade, 2003b: 282, located it in EZGT.]
    • Combination in Proceratium: Brown, 1958g: 248.
    • Status as species: Terron, 1981: 102 (in key); Brown, 1958g: 248, 339; Bolton, 1995b: 367; Baroni Urbani & De Andrade, 2003b: 282 (redescription); Hita Garcia, et al. 2013: 222.
    • Distribution: Kenya.

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) - Sub-ergatoid gyne. The sole known specimen exhibits a regular worker morphology coupled with the presence of large eyes and of the anterior ocellus. Head slightly longer than broad, with the sides weakly diverging posteriorly. Vertex convex. Clypeus medially reduced, subconvex, with superficially crenulate margin and about as long as the antennal socket. Antennal socket with broad torulus. Frontal carinae raised, very close each other oil the two anterior thirds weakly diverging posteriorly and on the last third connected each other and almost perpendicular to the cephalic capsule. Lateral expansions of the frontal carinae narrow. Genal carinae absent. Gular area not impressed. Eyes relatively large, with ca. 25 ommatidia and below the midline of the head. Anterior ocellus present and developed. First funicular joint 1/5 longer than broad. Funicular joints 2-10 broader than long. Last funicular joint about as long as the sum of joints 7- 10. Scapes much short of the vertexal margin and gently thickening apically. Masticatory margin of the mandibles with 3-4 denticles before the pointed apical tooth. Palp formula not visible in the sole known specimen.

Mesosoma about as long as the maximum head length (mandibles included), convex dorsally. Propodeal suture superficially impressed dorsally. Promesopleural and meso-metapleural sutures impressed ventrally only. Basal face of the propodeum gently declivous posteriorly. Area between the basal and declivous faces with a relatively large, blunt tooth on each side. Propodeal lobes subround. Propodeal spiracle small, round and placed above mid height of the propodeuln in lateral view. Metapleural gland with inflated and transparent bulla.

Petiole with weakly cuneiform apex in profile broader than long, in dorsal view; its sides shortly diverging anteriorly and convex posteriorly. Anterior border of the petiole concave and marginate, the margin toothed on each side. Ventral process of the petiole lamelliform and subrectangular. Postpetiole in dorsal view broader than the petiole and with posteriorly diverging sides. Postpetiolar sternite anteromedially with a marked subconvex projection. Posterior half of the postpctiolar sternite convex. Constriction between postpetiole and gaster impressed. Gastral tergite I strongly convex and about 1/4 longer than the postpetiole. Castral sternite I subround and projecting anteriorly. Remaining gastral tergites and sternites curved ventrally.

Legs slender but not very elongate. All tibiae with a pectinate spur. Spurs of fore legs without basal spine. Fore basitarsi longer than the mid ones. Hind basitarsi about 1/5 shorter than hind tibiae. Tarsomeres of mid and hind legs missing in the holotype. Pretarsal claws of fore legs simple. Arolium of fore legs developed.

Sculpture. Head, mesosoma and petiole granulate, the granulation more marked on the head. Postpetiole, gaster and legs smooth and with sparse, minute, superficial punctures.

Body covered by the following types of hairs (only the head and part of the mesosoma have well preserved hairs): (1) short, dense, suberect, on the head and mesosoma; (2) longer than type (1), suberect, rare on the head, on the mesosoma and on the scapes; (3) long, subdecumbent on the petiole, postpetiole and gaster; (4) shorter than hair type (1), dense, subdecumbent and decumbent on the funicular joints. In addition the funicular joints bear whitish, thick, appressed, short, sparse hairs.

Colour light brown; area behind the ocelli darker.

Measurements in mm and Indices: TL 3.17; HL 0.77; HW 0.72; EL 0.10; SL 0.53; WL 0.88; PeL 0.25; PeW 0.28; HFeL 0.58; HTiL 0.48; HBaL 0.40; LS4 0.15; LT4 0.65; CI 93.5; SI 68.8; IGR 0.23.

Type Material

Baroni Urbani and de Andrade (2003) - Type locality: Nairobi, Kenya. Type material: holotype sub-ergatoid gyne labelled: "Kenia, Nairobi, IX-45, S. Patrizi leg., Sysphincta toschii Cons., 1949 det. M. Consani" in DIVA, examined.


  • 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 282, fig. 118 queen described)
  • Brown, W. L., Jr. 1958g. Contributions toward a reclassification of the Formicidae. II. Tribe Ectatommini (Hymenoptera). Bulletin of the Museum of Comparative Zoology 118: 173-362 (page 248, Combination in Proceratium)
  • Consani, M. 1951. Formiche dell'Africa Orientale I. Boll. Ist. Entomol. Univ. Studi Bologna 18: 167-172. (page 167, fig. 1 worker described)

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.
  • Brown W. L., Jr. 1958. Contributions toward a reclassification of the Formicidae. II. Tribe Ectatommini (Hymenoptera). Bulletin of the Museum of Comparative Zoology 118: 173-362.
  • Garcia F.H., Wiesel E. and Fischer G. 2013.The Ants of Kenya (Hymenoptera: Formicidae)—Faunal Overview, First Species Checklist, Bibliography, Accounts for All Genera, and Discussion on Taxonomy and Zoogeography. Journal of East African Natural History, 101(2): 127-222
  • Hita Garcia F.; P. G. Hawkes, and G. D. Alpert. 2014. Taxonomy of the ant genus Proceratium Roger (Hymenoptera, Formicidae) in the Afrotropical region with a revision of the P. arnoldi clade and description of four new species. ZooKeys 447:47–86.
  • Terron G. 1981. Deux nouvelles espèces éthiopiennes pour le genre Proceratium (Hym.: Formicidae). Annales de la Faculté des Sciences de Yaoundé 28: 95-103.