Rhopalothrix plaumanni

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Rhopalothrix plaumanni
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Rhopalothrix
Species: R. plaumanni
Binomial name
Rhopalothrix plaumanni
Brown & Kempf, 1960
Synonyms

Specimens were collected from ground litter. Little else is known about the biology of Rhopalothrix plaumanni.

Identification

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Longino and and Boudinot (2013) - Knowledge of the biology of the Rhopalothrix isthmica clade of Rhopalothrix is conjectural; a nest has never been recovered and a live specimen never seen. What we know is based on locations and frequencies of capture using various mass-sampling methods. Specimens are known from wet to moderately seasonal forest, from sea level to 2140 m elevation. At higher elevation, they are found in diverse mesophyll forest and in forests with various combinations of Liquidambar and montane oak. In Costa Rica, they are restricted to the wet forests of the Atlantic slope, to 1500 m on the Barva Transect in the Cordillera Volcánica Central and to 800 m in the Cordillera de Tilarán. The genus is unknown from the Monteverde cloud forest at 1500 m, the lowland wet forests of the Osa Peninsula, and the lowland tropical dry forests of Guanacaste, in spite of intensive collecting efforts in these areas. Further north in Central America they can occur at higher elevations.

In quantitative sampling at La Selva Biological Station, in the Atlantic lowlands of Costa Rica, occurrences were relatively more frequent in soil/litter cores than in samples of sifted litter from the soil surface. This suggests that nests are subterranean, with workers only occasionally venturing up into the litter layer. Dealate queens are known for a few species, occurring occasionally in Winkler or Berlese samples. Alate queens of one La Selva species were found in canopy fogging samples, one each in two separate fogging events. Oddly, alate queens have not been found in the many Malaise samples from La Selva. Males remain unknown.

Castes

Nomenclature

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

  • plaumanni. Rhopalothrix plaumanni Brown & Kempf, 1960: 235, fig. 58 (w.) BRAZIL. Senior synonym of acutipilis: Longino & Boudinot, 2013: 315.
  • acutipilis. Rhopalothrix acutipilis Kempf, 1962b: 28, fig. 28 (q.) BRAZIL. Junior synonym of plaumanni: Longino & Boudinot, 2013: 315.

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

Longino and Boudinot (2013) - In this study queens were associated with workers for three Central American species. The queens differed from the workers in pilosity and the shape of the face. The queens bore numerous short bristles, which are lacking on the workers, and the worker faces had much stronger grooves and gibbosities. The characteristics of the mandible and labrum were shared between queens and workers. Examination of the figures for R. plaumanni and R. acutipilis, the types of which are from the same locality and by the same collector, suggest that R. acutipilis is the queen of R. plaumanni.

Description

Worker

Holotype. TL 1.85, HL 0.43, HW 0.47 (CI 108), ML 0.13, WL 0.51 mm.

Form of head and mandibles shown. This is a close relative of weberi and isthmica. Note the small, single-facetted eyes and the deeply notched bilobed labral shield. Following are the main distinctive characters:

1. Dorsum of head lacking the pair of well-defined and moderately arched transverse ridges and sulci of weberi; instead only a feeble, blunt and strongly arched posterior ridge is present. Disc in front of this ridge flattened to weakly concave.

2. Mandibles relatively short, at their bases only about half as wide as the labral shield. Dentition of masticatory margin, from base to apex, as follows: 2 blunt and indistinct denticles, 1 smaller acute tooth, a indistinctly denticulate diastema, 2 longer acute teeth, the basal slightly longer than the distal, 1 very long spiniform subapical tooth with a small reclinate denticle at its base, 2 small intercalary teeth on apical fork, the first usually rudimentary, 1 spiniform long apical tooth, subequal in length to subapical tooth, the latter slightly longer than width of mandibles at base.

3. Anterior clypeal margin feebly concave as in weberi, the lateral condylar gibbosities not as prominent as in isthmica.

4. Thoracic dorsum rather flat. Promesonotal suture vestigial. Metanotal groove extremely shallow and scarcely impressed. Propodeal spines subrectangular, not acute as in isthmica nor blunt as in weberi; infradental lamella, as seen in profile, weakly but evenly concave. Petiole with a rather short peduncle.

5. Erect pilosity extremely scarce, apparently confined to gastric apex (exposed portions of tergites and sternites II-IV each bearing a transverse row of several spatulate hairs), and leading edge of scape (with 2 reclinate spatulate setae basad, 6 standing spatulate setae apicad of elbow). Extensor surfaces of tibiae at apices and of the tarsi their length with conspicuous, short, inclined, paddle-shaped hairs. Clypeus and adjoining areas of front with conspicuous oval or round subappressed setae. Ground pilosity consisting in minute, sparse, thickened standing setulae, arising from the punctures on head, thorax, and tergites and sternites of gaster.

6. Sculpture as in isthmica, normally exposed surfaces opaque, punctulate-granulose with minute tuberculae. Color fuscous-brown; mandibles, clypeus, antennae, legs rather sordid testaceous.

Paratype has the following measurements: TL 1.75, HL 0.42, HW 0.47 (CI 113), WL 0.49 mm, but is otherwise identical with the holotype.

Type Material

Holotype a worker taken from sifted soil cover at Nova Teutonia, Santa Catarina, Brazil (F. Plaumann leg.), deposited in WWK (from CTB). Another worker paratype from the same collection (Museum of Comparative Zoology).

Longino and Boudinot (2013):

Holotype, worker: Brazil, Santa Catarina: Nova Teutônia (F. Plaumann) Museu de Zoologia da Universidade de Sao Paulo, paratype worker at Museum of Comparative Zoology (not examined).

Rhopalothrix acutipilis Holotype, queen: Brazil, Santa Catarina: Nova Teutônia, V-1960 (F. Plaumann) (not examined).

References

  • Brown, W. L., Jr.; Kempf, W. W. 1960. A world revision of the ant tribe Basicerotini. Stud. Entomol. (n.s.) 3: 161-250 (page 235, fig. 58 worker described)
  • Longino J. T. and Boudinot B. E. 2013. New species of Central American Rhopalothrix Mayr, 1870 (Hymenoptera, Formicidae). Zootaxa. 3616:301-324. doi:10.11646/zootaxa.3616.4.1