Simopone dignita

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Simopone dignita
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Simopone
Species: S. dignita
Binomial name
Simopone dignita
Bolton & Fisher, 2012

Simopone dignita casent0009816 p 1 high.jpg

Simopone dignita casent0009816 d 1 high.jpg

Specimen Labels

The type material was found in a dead branch above the ground in tropical dry forest.

Identification

A member of the emeryi species group. Simopone trita and S. dignita form a small complex of species that in Madagascar is morphologically intermediate between the silens and emeryi complexes. They combine the reduced pilosity of the latter with the stocky AIII and posteriorly shifted eyes of the former. The two species are easily differentiated by the characters noted in the key but in addition the posterior margins of tergites AIII and AIV in trita have a few short setae at most, whereas in dignita these margins each have a fringe of distinct setae that are obviously curved towards the midline. (Bolton and Fisher 2012)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Malagasy Region: Madagascar (type locality).


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Little is known about the biology of most species of Simopone. Specimens are rarely collected, and the number of species known only from workers is telling in regards to a lack of nest samples. Species are almost entirely arboreal but on occasion foraging workers are found on the ground or in rotten logs. Prey records are extremely sparse. They consist only of Crematogaster brood by Simopone vepres, and the brood of Terataner by Simopone sicaria. Nevertheless, these two records support the general supposition by Brown (1975) that most or all members of tribe Cerapachyini prey on other ants, or more probably the brood of other ants, but actual records are extremely rare. (Bolton and Fisher 2012)

Castes

Worker

Nomenclature

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

  • dignita. Simopone dignita Bolton & Fisher, 2012: 45, figs. 37-39 (w.) MADAGASCAR.

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

Description

Worker

(holotype in parentheses). HL 1.44–1.82 (1.60), HW 1.00–1.34 (1.18), SL 0.40–0.57 (0.50), EL 0.39–0.48 (0.44), PW 0.80–1.11 (0.99), AIIW 0.80–1.06 (0.97), AIIL 0.76–0.92 (0.85), AIIIW 0.91–1.26 (1.09), AIIIL 0.90–1.16 (1.02), WL 1.58–2.16 (1.92), MFL 0.80–1.18 (1.02), CI 69–74 (74), SI 39–43 (42), EL/HW 0.35–0.39 (0.37), EP 1.10–1.24 (1.24), AIIW/AIIL 1.05–1.16 (1.14), AIIIW/AIIIL 1.01–1.17 (1.07) (8 measured).

In full-face view anteriormost points of frontal lobes are about level with the midpoint of the shallowly convex to transverse anterior clypeal margin. Eyes located behind the cephalic midlength (EP 1.10–1.24). Leading edge of scape with at least one projecting seta that is curved or inclined toward the scape apex. In full-face view sides of head in front of eyes usually without projecting short setae, but one or two may occur; behind eyes only with minute pubescence that is appressed or very nearly so. In profile frontal carinae with relatively long setae and cephalic dorsum with 2–3 standing short setae above the eye, and usually also with a very few decumbent setae that are located more posteriorly. Cephalic dorsum between eyes densely but shallowly punctate, the punctures adjacent or nearly so. Anterior and dorsal surfaces of pronotum separated by an angle or weak margination, but without a strongly defined carina. Propodeal dorsum meets declivity through a blunt angle, without a transverse carina. Promesonotal suture weakly impressed; metanotal groove vestigial to absent. Mesosoma in dorsal view not distinctly constricted at the mesonotum; mesosoma narrowest across pronotum, mesonotum the same width or fractionally broader, broadest across propodeum (in holotype PW 0.99, maximum width across mesonotum 1.00, maximum width across propodeum 1.06). Dorsum of mesosoma densely finely punctate everywhere. Mesosoma with a short seta close to the pronotal humeri (very easily abraded away); mesosoma otherwise without setae but entire dorsum with appressed pubescence. Dorsal (outer) surfaces of mesotibiae and metatibiae mostly with a projecting seta present close to their apices; often with another close to the midlength. Dorsal surface of AII (petiole) meets anterior surface in a narrowly rounded angle, without a transverse carina. Posteriorly the dorsum of AII lacks a sharp carina but a weak ridge is present above the foramen. In dorsal view the posterior corners of AII are extended into small but stout triangular teeth that project posterolaterally. Lateral surface of AII, below the dorsolateral margin and above the level of the spiracle, without a longitudinal ridge or carina that extends the length of the sclerite. In dorsal view AII and AIII distinctly broader than long; AIV also broader than long. Abdominal tergite AII at most with one or two setae posteriorly, but AIII and AIV each with a fringe of setae along the extreme apical margin; the setae curved towards the midline and the central ones crossing over. All three tergites also with greyish appressed pubescence. Setae distinct on sternites of AIII and AIV. Abdominal tergites AII to AIV sculptured only with small punctures. Full adult colour black, appendages blackish brown to black; clypeus usually slightly lighter in shade than remainder of head capsule.

Holotype Specimen Labels

Type Material

Holotype worker, Madagascar: Prov. Mahajanga, PN Namoroka, 17.8 km 329° WNW Vilanandro, 100 m, 16°22.6’S, 45°16.6’E, 8-12.xi.2002, BLF6561, CASENT0009816, ex dead branch above ground, tropical dry forest (B.L. Fisher) (California Academy of Sciences). Paratypes. 3 workers with same data as holotype but CASENT0489939; 3 workers with same data but CASENT0489940 (bottom worker on pin with AII to apex detached and mounted separately); 3 workers with same data but CASENT0489941 (CASC).

References

  • Bolton, B. & Fisher, B.L. 2012. Taxonomy of the cerapachyine ant genera Simopone Forel, Vicinopone gen. n. and Tanipone gen. n. (Hymenoptera: Formicidae). Zootaxa, 3283, 1–101.