Rhopalothrix megisthmica

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Rhopalothrix megisthmica
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Rhopalothrix
Species: R. megisthmica
Binomial name
Rhopalothrix megisthmica
Longino & Boudinot, 2013

Rhopalothrix megisthmica casent0612564 p 1 high.jpg

Rhopalothrix megisthmica casent0612564 d 1 high.jpg

Specimen Labels

This species occurs in cloud forest habitats, from 1400–2000m elevation. All specimens are from Winkler or Berlese samples of sifted leaf litter. It is sympatric with Rhopalothrix isthmica at the type locality and with Rhopalothrix triumphalis on the slopes of Volcán Tacaná in Chiapas. At the type locality it was moderately abundant, occurring in 24 of 100 miniWinkler samples. (Longino and Boudinot 2013)

Identification

Differing from Rhopalothrix isthmica in larger size (HW > 0.73 versus < 0.69), and with propodeal tooth larger and more acute.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Guatemala (type locality), Mexico.

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.

Worker

Nomenclature

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

  • megisthmica. Rhopalothrix megisthmica Longino & Boudinot, 2013: 313, figs. 1B, 2C, 3F, 9, 16 (w.) GUATEMALA.

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

Description

Worker

HW 0.73–0.83 (n=12); mandible with two or three teeth on masticatory margin (can vary within individuals, with two teeth on one mandible and three teeth on the other), second tooth from base largest; subapical tooth with distinct 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 trapezoidal, anterior lobes triangular, inner margins of lobes shallowly sloping to semicircular median notch; metanotal groove moderately to strongly impressed; propodeal tooth usually large and acute (shorter and obtuse on one specimen), infradental lamella evenly and shallowly concave; squamiform setae abundant on first gastral tergite, either uniformly covering entire tergite or covering at least 3/4 of posterior portion.

Type Material

Holotype Specimen Labels

Holotype, worker. Guatemala, Zacapa: 2 km SE La Union, 14.94460 −89.27726 ±57 m, 1550 m, 12 May 2009, cloud forest, ex sifted leaf litter (LLAMA Wm-B-03-1-05) California Academy of Sciences, unique specimen identifier CASENT0612564]. Paratypes (workers): same data as holotype but 14.94665 -89.27593 ±50 m (LLAMA#Wa-B-03-1-04) National Museum of Natural History, CASENT0614540; 14.94677 -89.27585 ±50 m (LLAMA#Wa-B-03-1-07) Museum of Comparative Zoology, CASENT0614546; 14.94723 -89.27707 ±50 m (LLAMA#Wa-B-03-1-45) Universidad Nacional Autonoma de Mexico, CASENT0612503; 14.95372 -89.27618 ±50 m, 1430 m (LLAMA#Wa-B-03-2-31) Colección de Artrópodos, CASENT0629572; Colección Entomológica de El Colegio de la Frontera Sur, CASENT0629573; 3.5 km SE La Union, 14.95 -89.27 (unknown error), 1500 m, 4 Jun 1991 (R.S. Anderson#RSA91-050) Los Angeles County Museum of Natural History, CASENT0603567; Escuela Agricola Panamericana, CASENT0603699.

Etymology

Referring to its similarity to R. isthmica, differing mainly in larger size.

References

  • 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