Rhopalothrix megisthmica

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 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

• Key to Rhopalothrix species

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 14.95372° to 14.9446°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: AntMaps

Distribution based on Regional Taxon Lists

Neotropical Region: Guatemala (type locality), Mexico.

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Explore Overview of Rhopalothrix 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 are only known for Rhopalothrix apertor. ‎

Castes

Known only from the worker caste.

Worker

.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

• 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

References based on Global Ant Biodiversity Informatics

• Longino J. T. L., and M. G. Branstetter. 2018. The truncated bell: an enigmatic but pervasive elevational diversity pattern in Middle American ants. Ecography 41: 1-12.
• Longino J. T., and B. E. Boudinot. 2013. New species of Central American Rhopalothrix Mayr, 1870 (Hymenoptera, Formicidae). Zootaxa 3616: 301-324.