Ants of Los Tuxtlas

Ants of Los Tuxtlas Biological Station, Veracruz, Mexico

Report by John T. Longino, Michael G. Branstetter, The University of Utah; Jorge Valenzuela, Instituto de Ecología, Xalapa, Mexico. Student participants: Mario Augillar Mendez (Guanajuato), Brianna Bartholomew (Univ. Utah), Rhea Cone (Univ. Utah), Erika Alejandra Conti González (Guanajuato), Miguel Angel García-Martínez (INECOL), Kyle Gray (UC Davis), Dennis Infante (INECOL), Anamin Saraí Lizama Ramírez (Guanajuato), Jaqueline Ochoa Vega (Guanajuato), Madai Rosas Mejía (Guanajuato), Gabriel Somarriba (Univ. Florida).

This is a list of the ants of Los Tuxtlas Biological Station, Veracruz, Mexico, based on Project ADMAC sampling and previous records from the station. Phil Ward provided the list of Pseudomyrmex, based on ADMAC sampling, previous collecting by Ward, and museum records.

Project ADMAC carried out ant sampling at Los Tuxtlas from 28 May to 1 June 2016. Sampling included two miniWinkler transects of 50 samples each (5 m spacing; red dots), maxiWinkler samples (yellow dots), baiting transects (20 baits each, blue dots), beating samples (2hrs, green dots), and Malaise traps (white dots). MaxiWinkler sampling was distributed along an elevational gradient to the 500 m peak southwest of the station buildings.

Specimen records have been uploaded to the AntWeb database and are periodically updated. Names in the species list are linked to individual specimen records on AntWeb, from which a link can be followed to the general species page. These specimens function as site-specific vouchers, whose identities may change. The species names in the list are static text on this page. Following the specimen link to AntWeb will allow one to see if the name has changed.

There are at least 191 species. The fauna is an attenuated version of the lowland rainforest fauna that extends along the Caribbean slopes south to Costa Rica. For many of the species Los Tuxtlas is their northern range limit.

Notable discoveries include:

Acropyga tricuspis. This species was previously known from a few collections near Manaus. A single specimen was found in an ADMAC Winkler sample. It has the diagnostic mandible shape described in LaPolla's revision. We have seen no other specimens like it in Central America.

Adelomyrmex. Our sampling substantially extended the geographic range of two Central American species, A. longinoi and A. metzabok.

Fulakora JTL002. This is a genus in the subfamily Amblyoponinae. Many Neotropical species formerly placed in Amblyopone and then Stigmatomma are now in Fulakora. We thought the Central American species were pretty well known, but we found an alate queen in one Winkler sample that was very different from any other known Fulakora. It is clearly an interesting new species, very distinct from any other species.

Myrmelachista JTL025. Myrmelachista is a Neotropical genus of arboreal ants, some of which are generalists, nesting in live or dead stems, and some of which are specialized associates of a few genera of small, understory rainforest trees in the Lauraceae and Meliaceae. These specialist understory ants were not discovered until the 1970s, and taxonomic work has since focused on Costa Rica. But an early report noted the occurrence of unidentified Myrmelachista at Los Tuxtlas (Ibarra-Manríquez, G. & Dirzo, R. 1990. Arboreal myrmecophilous plants from Los Tuxtlas Biological Station, Veracruz. Revista de Biologia Tropical 38: 79–82). It was gratifying to find some of these at Los Tuxtlas and collect good series with queens. On comparison with species from Costa Rica, these are clearly undescribed, distinct from any of the Costa Rican species.

Neivamyrmex cf. diana. This is a minute army ant, a single worker of which was found in a Winkler sample. True N. diana is from southern Brazil, and does not quite match these. Interestingly, this diana-like species is now known from one collection from Bolivia, one collection from Costa Rica, and now this one occurrence at Los Tuxtlas.

Pheidole. As is typical, there is a substantial Pheidole fauna, with at least 32 species. Four of them are distinctive enough that they are almost certainly undescribed species. We have placed most specimens in 28 known species, but many of these are actually species complexes. With more knowledge many of these will certainly be broken up into multiple species, and thus the Los Tuxtlas versions may gain new names with time. One we can rely on, though, is P. tuxtlasana! This species was named by E. O. Wilson in 2003 and the type locality is Los Tuxtlas.

Rhopalothrix triumphalis. It was great to see multiple collections of this rare litter ant. The species was previously known from a few specimens from the Sierra de Chiapas and a single specimen from a site in northeastern Guatemala.

Strumigenys manis. Barry Bolton described this distinctive species in 2000, based on a collection Phil Ward made at Los Tuxtlas in 1985. It turned out to be quite common in ADMAC Winkler samples, but remains a local endemic, known only from Los Tuxtlas.