Microdaceton exornatum

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Microdaceton exornatum
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Microdaceton
Species: M. exornatum
Binomial name
Microdaceton exornatum
Santschi, 1913

Microdaceton exornatum casent0101453 profile 1.jpg

Microdaceton exornatum casent0101453 dorsal 1.jpg

Specimen Label

Synonyms

Identification

The two similar species Microdaceton exornatum and Microdaceton tibialis can be separated as follows:

exornatum tibialis
Mandibles relatively shorter, MI 55-61. Mandibles relatively longer, MI 63-69.
Scapes relatively shorter, SI 66-70. Scapes relatively longer, SI 75-81.
Postpetiole in dorsal view spanning almost the entire basal width of the first gastral tergite. Postpetiole in dorsal view spanning 0.70 or less of the basal width of the first gastral tergite.
Width of postpetiole in dorsal view 0.60-0.65 X maximum width of first gastral tergite. Width of postpetiole in dorsal view 0.46-0.56 X maximum width of first gastral tergite.
Basigastral costulae usually dense and distinct, rarely reduced in intensity. Basigastral costulae absent, at most with faint shagreening near gastral base.
Body colour yellow. Body colour black to blackish brown.
Laterodorsal cephalic tubercles large and conspicuous. Laterodorsal cephalic tubercles vestigial to absent.
Petiolar armament spiniform. Petiolar armament dentiform.
Propodeal dorsum with reticulate-punctate sculpture. Propodeal dorsum without reticulate-punctate sculpture.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Kenya, Mozambique, South Africa (type locality), United Republic of Tanzania, Zambia, Zimbabwe.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

Nomenclature

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

  • exornatum. Microdaceton exornatum Santschi, 1913g: 478 (w.) SOUTH AFRICA. [Also described as new by Santschi, 1914e: 33.] Arnold, 1948: 225 (q.). Senior synonym of laevior, leakeyi: Bolton, 1983: 402. See also: Bolton, 2000: 28.
  • leakeyi. Microdaceton leakeyi Patrizi, 1947: 219, figs. 1, 2 (q.) KENYA. Bernard, 1953b: 253 (w.). Junior synonym of exornatum: Bolton, 1983: 402.
  • laevior. Microdaceton exornatum var. laevior Arnold, 1948: 225 (w.q.) SOUTH AFRICA. Junior synonym of exornatum: Bolton, 1983: 402.

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

Description

Worker

Bolton (1983) - TL 3.0-4.0, HL 0.79-1.00, HW 0.76-0.94, CI 92-96, ML 0.48-0.58, MI 55-61, SL 0.50-0.64, SI 66-70, PW 0.40-0.50, AL 0.70-0.90 (10 measured).

Mandibles elongate and linear, without preapical armament but armed apically with a fork of 3 long spiniform teeth set in a more or less vertical series, the apical fork teeth without intercalary denticles. Anterior clypeal margin with a small median notch or indentation. Eyes large and conspicuous, clearly visible in full-face view. Antennal scrobes absent, frontal carinae absent, the antennal fossa ventrally on each side with a small laterally projecting tubercle in front of the eye. Occipital lobes with 2 pairs of tubercles which are variable in size, the first pair laterodorsal, the second pair at the posteriormost point of the lobes. Clypeus coarsely punctate to narrowly foveolate, with appressed to slightly elevated fine simple ground-pilosity, without standing or specialized hairs of any description. Dorsum of head foveolate, with a fine short simple hair arising from the centre of each foveola, the hairs appressed or nearly so, the head without specialized or standing pilosity. In profile the dorsal surface of the head rising and shallowly convex from the posterior clypeal margin to about the midlength, then suddenly depressed. Sides of head foveolate as dorsum. Dorsal outline of alitrunk dominated by the strong subconical mesonotal teeth or tubercles and the long propodeal spines, the latter without or only with a vestige of an infradental lamella. Metapleural lobes long and broad, slightly upcurved. Sides of alitrunk foveolate but on the mesopleuron the sculpture may be partially or almost wholly effaced. Dorsal surfaces of pronotum and mesonotum strongly foveolate, the metanotal groove with short longitudinal cross-ribs. Propodeal dorsum reticulate-punctate, sometimes with one or two laterally situated partial foveolae. Alitrunk without specialized or bizarre pilosity, only with fine short simple hairs arising from the foveolar centres. Usually these hairs are very short inconspicuous and appressed, but in some they may be longer and slightly elevated. Petiole in profile without spongiform or alar appendages, armed dorsally with a pair of spines and posterodorsally with a sharp triangular elevation. Postpetiole without spongiform tissue but with strong lateral alar prominences which appear in profile as thick longitudinal crests. In dorsal view the postpetiole very broad, spanning almost all of the basal width of the first gastral tergite. Basigastral costulae present, usually fine dense and distinctive, only rarely reduced in intensity. Petiole and postpetiole densely reticulate-punctate to granular. Petiole, postpetiole and first gastral tergite without standing hairs of any description, only with minute appressed sparse pubescence. Colour yellow, the appendages paler than the body.

Type Material

Holotype worker, SOUTH AFRICA: Natal Zululand (I. Triigardh) (not in NMB; presumed lost).

References

  • Arnold, G. 1948. New species of African Hymenoptera. No. 8. Occas. Pap. Natl. Mus. South. Rhod. 2: 213-250 (page 225, queen described)
  • Bolton, B. 1983. The Afrotropical dacetine ants (Formicidae). Bull. Br. Mus. (Nat. Hist.) Entomol. 46: 267-416 PDF (page 402, senior synonym of laevior and leakeyi)
  • Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 28, see also)
  • Santschi, F. 1913g. Genre nouveau et espèce nouvelle de Formicides (Hym.). Bull. Soc. Entomol. Fr. 1913: 478 (page 478, worker described)
  • Santschi, F. 1914e. Meddelanden från Göteborgs Musei Zoologiska Afdelning. 3. Fourmis du Natal et du Zoulouland récoltées par le Dr. I. Trägårdh. Göteb. K. Vetensk. Vitterh. Samh. Handl. 15: 1-44 (page 33, also described as new)