Proceratium gibberum

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Proceratium gibberum
Temporal range: Burdigalian, Early Miocene Dominican amber, Dominican Republic
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Proceratiinae
Tribe: Proceratiini
Genus: Proceratium
Species: P. gibberum
Binomial name
Proceratium gibberum
De Andrade, 2003

A fossil species described from a Dominican amber specimen.


A member of the avium group (stictum clade) and differing from all the species of this group by the gastral tergite I with a broad tumulus on the curvature.


This taxon was described from Dominican amber, Dominican Republic (Burdigalian, Early Miocene).



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

  • gibberum. †Proceratium gibberum De Andrade, in Baroni Urbani & De Andrade, 2003b: 68, fig. 14 (q.) DOMINICAN AMBER (Dominican Republic, Miocene).

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 sides parallel anteriorly and weakly diverging posteriorly. Vertex slightly convex in full face view and flat in posterior view. Clypeus broad, convex, protruding anteriorly and surrounding the whole antennal insertions. Anteromedian margin of the clypeus, on each side, angulate and with a very superficial notch. Frontal carinae apart each other, diverging posteriorly and not covering the antennal insertions. Lateral expansions of the frontal carinae narrow and low. Frons concave medially. Genal carinae marked and ending at about level of eyes posteriorly. Gular area gently concave. Eyes large and slightly below the mid-line of the head and with ocular pilosity. Ocelli developed. Scapes reaching the vertexal border. First funicular joint about 1/3 longer than broad. Funicular joints 2-10 slightly longer than broad. Last funicular joint as long as the sum of joints 7- 10. Mandibles with 4-5 denticles before the apical tooth. Palp formula apparently 4,3.

Mesosoma robust. Pronotum perpendicular to mesonotum. Mesonotum gently convex. Parapsidal furrows impressed. Scutellum as high as mesonoturn and broadly round posteriorly. Metanotum with a pointed spine. Propodeum with distinct basal and declivous faces laterally separated by a pointed tooth. Basal face of the propodeum dorsomedially concave and declivous posteriorly. Each side of the declivous face of the propodeurn with a posterior crenulate lamella ending in a subround tooth. Propodeal lobes truncate. Propodeal spiracle tumuliform and over mid height in lateral view.

Petiole slightly longer than broad, in dorsal view with the sides diverging on the anterior third and convex on the two posterior thirds. Anterior border of the petiole gently concave and carinate, the carina denticulate on each side. Ventral process of the petiole spiniform. Postpetiole about 0.2 shorter than gastral tergite I (LT4), in side view with a short tumulus close to the middle of the posterior border and in dorsal view with the sides gently diverging posteriorly. Postpetiolar sternite anteromedially with a marked subtriangular projection. Constriction between postpetiole and gastral segment I impressed. Gastral tergite I with a broad tumulus on the curvature. Remaining gastral tergites and sternites retracted.

Legs slender, slightly elongate. All tibiae with a pectinate spur. Spurs of fore legs with a basal spine. Fore basitarsi slightly shorter than the mid ones. Hind basitarsi very long and about 1/8 shorter than hind tibiae. Second tarsomere of mid and hind legs longer than third and fourth tarsomeres, and about as long as the pretarsus. Pretarsal claws simple. Arolia present.

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

Sculpture. Head deeply irregularly reticulate, minutely punctate; in addition to these sculptures, the vertex and the sides of the head irregularly foveolate-granulate. Mesosoma, petiole and postpetiole irregularly foveolate-granulate. First gastral tergite densely reticulate-punctate. Legs and scapes densely punctate.

Body covered by hairs of three main types: (1) short, dense, suberect or subdecumbent on the whole body, very sparse on the funicular joints; (2) long, suberect or subdecumbent, relatively dense and sparse on the whole body but absent on the scapes and on the funicular joints; (3) shorter than hair type ( l ) , dense and appressed on the funicular joints only. In addition, the funicular joints bear thick, appressed, short, sparse hairs and the scapes sparse hairs shorter than hair type (2).

Colour black.

Measurements in mm and Indices: TL 5.26; HL 1.12; HW 1.02; EL 0.22; SL 0.87; WL 1.54; PeL 0.56; PeW 0.52; HFeL 1.16; HTiL 0.87; HBaL 0.81; LS4 0.26; LT4 1.00; CI 91.1; SI 77.7; IGR 0.26.

Type Material

Holotype wlnged gyne In the amber sample MCZC-25 from Yanigua, a small agglomerabon 3 km W of the mine El Valle, in Museum of Comparative Zoology.


From the Latin "gibber" (Plinius) = hump-backed, referring to the gastral morphology of this species.


  • 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 68, fig. 14 queen described)