Proceratium denticulatum

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Proceratium denticulatum
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. denticulatum
Binomial name
Proceratium denticulatum
Lattke, 1991

Lattke 1991b-3 Proceratium-denticulatum hal.jpg

A fossil species known from Dominican amber.

Identification

A member of the avium group (stictum clade) where it occupies the basalmost position. It differs from the next in-group species, Proceratium gibberum and Proceratium diplopyx, by the gastral tergite I simply round, without broad tumulus or exaggerated expansion on the curvature, by the fore basitarsi longer than the mid basitarsi instead of as long as the mid ones, by the TL = 4.27 mm instead of 5.26 mm. . It shares with all other species of the group the funicular joints 2-9 longer than broad. In body shape and sculpture it resembles the Dominican fossil gibberum and two recent species, Proceratium boltoni and Proceratium cavinodus from Ghana and Australia respectively. denticulatum has the gastral tergite I superficially reticulate-punctate; a similar sculpture is also present in gibberum but in this species it is larger and deeper. (Baroni Urbani and de Andrade (2003)

Distribution

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

Castes

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • denticulatum. †Proceratium denticulatum Lattke, 1991b: 101, figs. 1, 2 (q.) DOMINICAN AMBER (Miocene). See also: Baroni Urbani & De Andrade, 2003b: 66.

Type Material

Holotype: One wingless gyne labelled "Ambar Dominican, 20-23 X 10^6 anos, Donacion: Sra Mary Lou Gadou, Holotipo, Procetatlum denticulatum, det J. Lattke 1987", in Instituto de Zoologia Agricola, examined by Baroni Urbani and de Andrade (2003).

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

Description

Queen

Baroni Urbani and de Andrade (2003) - Head longer than broad. Sides of the head subparallel anteriorly and weakly converging posteriorly. Vertex 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 with a superficial notch denticulate on each side; each denticle with a short, dorsal, convergent carina. Frontal carinae separate from each other, subparallel and not covering the antennal insertions. Lateral expansions of the frontal carinae narrow and low. Frons deeply concave medially. Genal carinae marked. Eyes large and below the midline of the head and with ocular pilosity. Ocelli developed. Scapes slightly surpassing the vertexal margin. First funicular joint about 1/2 longer than broad. Funicular joints 2-10 slightly longer than broad. Last funicular joint slightly longer than the sum of joints 8-10. Mandibles with 4-5 denticles before the apical tooth. Palp formula not visible.

Mesosoma robust. Pronotum perpendicular to mesonotum. Mesonotum gently convex. Parapsidal furrows superficially impressed. Scutellum about as high as inesonotum, with the sides gently converging and 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 dorso-medially concave and declivous posteriorly. Posterior sides of the declivous face of the propodeum with a crenulate lamella ending in a subpointed tooth. Propodeal lobes truncate. Propodeal spiracle tumuliform and above 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 concave and carinate, the carina denticulate on each side. Ventral process of the petiole spiniform. Postpetiole about 1/4 shorter than gastral tergite I (LT4). Postpetiole in profile with a short tumulus close to the middle of the posterior border and in dorsal view with the sides gently diverging posteriorly. Postpetiolar sternite with a marked subtriangular projection anteromedially; posterior half of the postpetiolar sternite convex. Constriction between postpetiole and gastral segment I impressed. Gastral tergite I strongly convex on the curvature. Remaining gastral tergites and sternites retracted.

Legs slender and elongate. All tibiae with a pectinate spur. Spurs of fore legs with a basal spine. Fore basitarsi slightly longer than the mid ones. Hind basitarsi very long and about 0.8 of the length of the hind tibiae. Second tarsoinere of mid and hind legs longer than third and fourth tarsomeres and about as long as the pretarsus. Pretarsal claws simple. Arolia small.

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

Body covered by hairs of three main types: (1) short, dense, suberect on the whole body, subdecumbent or erect and very sparse on the funicular joints; (2) long, suberect or subdecumbent on the whole body, sparse, slightly longer and denser on the petiole, but absent on the scapes and on the funicular joints; (3) shorter than hair type (1), 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 dark brown.

Measurements in mm and Indices: TL 4.27; HL 0.91; HW 0.82; EL 0.20; SL 0.72; WL 1.28; PeL 0.46; PeW 0.40; HFeL 1.00; HTiL 0.69; HBaL 0.60; LS4 0.20; LT4 0.82; CI 90.1; SI 79.1; IGR 0.24. We obtained smaller values in the measurements of the holotype of Proceratium denticulatum when compared with those of Lattke (1990) after re-polishing the amber sample.

References

  • 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 66, fig. 24 queen described)
  • Lattke, J. E. 1991b [1990]. The genus Proceratium Roger in Dominican amber (Hymenoptera: Formicidae). Caribb. J. Sci. 26: 101-103 (page 101, figs. 1, 2 queen described)