| Proceratium terroni|
The holotype was found by sifting decaying wood.
A member of the toschii clade and differing from its sister species Proceratium toschii, in the worker, by the lack of suberect, long hairs on the head and on the mesosoma. Both species share a shining postpetiole, a relatively rare trait appearing only among a few species of the silaceum clade. (Baroni Urbani and de Andrade 2003)
Keys including this Species
Distribution based on Regional Taxon Lists
Distribution based on AntMaps
Distribution based on AntWeb specimens
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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 New General Catalogue, a catalogue of the world's ants.
- coecum. Proceratium coecum Terron, 1981: 96, fig. 2 (w.) CAMEROUN. [Junior secondary homonym of Ponera caeca Donisthorpe, 1949b: 491, above.] Replacement name: terroni Bolton, 1995b: 367.
- terroni. Proceratium terroni Bolton, 1995b: 367. Replacement name for Proceratium coecum Terron, 1981: 91. [Junior secondary homonym of Ponera caeca Donisthorpe, 1949b: 491.] See also: Baroni Urbani & De Andrade, 2003b: 285.
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, with weakly convex sides gently converging into a strongly convex vertex. Clypeus medially reduced, subconvex, between the and about as long as the antennal sockets. Antennal socket with broad torulus. Frontal carinae raised, very close each other on the two anterior thirds gently convex and connected each other and almost perpendicular to the head capsule on the last third. Lateral expansions of the frontal carinae narrow. Anterolateral area close to the antennal insertions impressed. Genal carina absent. Gular area not impressed. Eyes absent. First funicular joint slightly longer than broad. Funicular joints 2-10 much 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. External border of the mandibles flat. Masticatory margin of the mandibles with 3 denticles before the pointed apical tooth. Palp formula 3,2.
Mesosoma gently convex and shorter than maximum head length (mandibles included) in profile. Promesopleural and meso-metapleural sutures iinpressed ventrally only. Basal face of the propodeum gently declivous posteriorly. Area between the basal and declivous faces of the propodeum gently concave medially and with a blunt tooth on each side. Propodeal lobes subround. Propodeal spiracle round and above the mid height in lateral view. Metapleural gland bulla inflated and transparent.
Petiole with the anterior half sloping anteriorly and with the posterior half convex in profile, broader than long in dorsal view; its sides anteriorly shortly diverging and posteriorly convex. Anterior border of the petiole V-shaped and marginate. Ventral process of the petiole lamelliform, subrectangular with concave ventral margin. Postpetiole in dorsal view with the anterior border slightly broader than the petiole; its sides gently diverging posteriorly. Postpetiolar sternite anteromedially with a large subconvex projection. Posterior half of the postpetiolar sternite convex. Constriction between postpetiole and gaster impressed. Gastral tergite 1 strongly convex and slightly longer than the postpetiole. Gastral sternite I subround and strongly projecting anteriorly. Remaining gastral tergites and sternites curved ventrally.
Legs slender and slightly elongate. All tibiae with a pectinate spur. Spurs of fore legs without basal spine. Fore basitarsi longer than the mid ones. Hind basitarsi 1/5 shorter than hind tibiae. Second tarsomere of hind legs subequal in size to the pretarsus. Pretarsal claws simple. Arolia developed.
Sculpture. Head, mesosoma and petiole granulate, the granulation strongly marked on the head and on the mesosoma, superficial on the petiole. Postpetiole, gaster and legs smooth and with sparse, minute, superficial, piligerous punctures.
Body covered by hairs of three main types: (1) short, dense, decumbent on the whole body, absent from the posterior half of the metapleurae, on the postero-lateral sides of the petiole and on the postpetiolar sternite; (2) longer than type (1), subdecumbent and restricted only on the posterior half of the metapleurae, on the postero-lateral sides of the petiole and on the postpetiolar sternite; (3) 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.
Measurements in mm and Indices: TL 2.53; HL 0.69; HW 0.61; EL absent; SL 0.46; WL 0.70; PeL 0.21; Pew 0.25; HFeL 0.48; HTiL 0.38; HBaL 0.27; LS4 0.12; LT4 0.44; CI 88.4; SI 66.7; IGR 0.27.
Baroni Urbani and de Andrade (2003) - Proceratium coecum Worker. Original description. Type locality: Kala, Cameroon. Type material worker labeled: "P. sp 2 OL, Cameroun: Kala, 950 m, (18 km W Yaounde), tamisage tissus ligneux en decomposition, 10.X.1972, G. Terron Leg., Proceratium coecum Terron, Holotype", in CIRA, 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 285, figs. 119, 120 worker described)
- Bolton, B. 1995b. A new general catalogue of the ants of the world. Cambridge, Mass.: Harvard University Press, 504 pp. (page 367, Replacement name for Preceratium coecum)
- Donisthorpe, H. 1949b . A fifth instalment of the Ross Collection of ants from New Guinea. Ann. Mag. Nat. Hist. 12(1): 487-506 (page 491, primary homonym)
- Terron, G. 1981. Deux nouvelles espèces éthiopiennes pour le genre Proceratium (Hym.: Formicidae). Ann. Fac. Sci. Yaoundé 28: 95-103 (page 91, [Junior secondary homonym of Ponera caeca Donisthorpe, 1949b: 491.])