Rhopalothrix stannardi

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

Rhopalothrix stannardi casent0280781 p 1 high.jpg

Rhopalothrix stannardi casent0280781 d 1 high.jpg

Specimen Labels

Recent collections of this species are from lowland wet to moist forest habitat, from 70–270m elevation. The type is apparently from a somewhat higher site near Ocosingo. All recent specimens are from Winkler samples of sifted leaf litter. In quantitative sampling carried out during Project LLAMA, this species occurred in 4 of 100 miniWinkler samples at a lowland Chiapas site and in 7 of 100 samples from in and near Tikal National Park in Guatemala. (Longino & Boudinot, 2013)

Identification

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Belize, Guatemala, Mexico (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

Known only from the worker caste.

Nomenclature

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

  • stannardi. Rhopalothrix stannardi Brown & Kempf, 1960: 236, fig. 57 (w.) MEXICO.

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

Description

Worker

Holotype. TL 2.7, HL 0.54, HW 0.56 (CI 104), ML 0.15, WL 0.55 mm.

Very similar to R. isthmica, but differing in the narrower head and otherwise as follows:

1. Blunt transverse crests across head, and corresponding sulci, well defined; more as in R. weberi. Sides of occipital lobes nearly evenly rounded. Eyes minute, each with a single facet.

2. Mandibles more slender, at their bases only about half as wide (0.09-0.10 mm) as the labral shield; in isthmica, the mandibular bases are distinctly more than half as wide as the labral shield. Subapical tooth about 0.12 mm long, slender and acute, feebly recurved. Dentition (basad of reclinate tooth at base of subapical tooth) consisting only of a subbasal denticle, a small middle tooth, and beyond the latter another very small denticle. The down turned apical tooth is only about 1/3 the length of the subapical tooth, from which it is separated by two smaller but acute intercalary teeth.

3. Labral shield broader than long, sides subparallel and nearly straight, anterolateral corners subacute; anterior margin broadly and very shallowly concave, and within this feebly tri-emarginate or sinuate, in no sense deeply excavated or notched. Each anterolateral corner bears a stout, tapered, anteriorly directed "trigger-hair".

4. Propodeal teeth with more evenly rounded infradental lamellae. Petiolar node more rounded behind, and with only a feeble ventral swelling. Alitrunk in profile appearing more evenly, and very gently, convex; metanotal impression very feeble.

5. Erect pilosity as in R. isthmica, but slightly less abundant and conspicuous, largely confined to angles of scapes and apical half of gaster. Extensor surfaces of tibiae at apices, and of the tarsi their lengths, with conspicuous short, inclined, paddle-shaped hairs. Underside of gaster just before apex with 10-12 peculiar, short, thorn-like projections, irregular in size, position and inclination, appearing to be outgrowths of the integument, but which may be either artifacts or modifications of the blunt setae found in the same positions on R. isthmica. Pubescence suppressed, apparent only toward gastric apex, where quite sparse.

6. Sculpture as in R. isthmica, normally exposed surfaces opaque, punctulate-granulose with minute tuberculae. Color sordid testaceous, head and anterior alitrunk slightly more brownish.

Longino and Boudinot (2013) - HW 0.53–0.59 (n=5); mandible with three widely spaced denticles on masticatory margin, middle denticle largest; subapical tooth with minute reclinate denticle at base; subapical tooth about twice as long as apical tooth; intercalary teeth prominent, one closest to apical tooth about half as long as apical tooth; labrum subrectangular, outer margins diverging anteriorly, anterior margin very shallowly and evenly concave, with minute notch medially; posterior margin of clypeus elevated above anterior face; arcuate grooves and ridges of face very shallow; mesosomal dorsum evenly and shallowly convex in profile, metanotal groove not or very weakly impressed; propodeal tooth obtuse to right angled, infradental lamella broad and descending almost perpendicularly from tooth; about 12 squamiform setae on posterior half of first gastral tergite.

Type Material

Holotype a unique, taken by Berlese or other sifting apparatus at Finca el Real, Ocosingo Valley, Chiapas, Mexico, July 1-7, 1950 (c. and M. Goodnight and L. J. Stannard leg.); deposited in Museum of Comparative Zoology.

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 236, fig. 57 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