Pseudomyrmex elongatus

Typically found nesting in dead twigs of live trees.

Identification
Ward (1989) - P. elongatus is a common and widespread species whose key features are its relatively small size (HW 0.56-0.68); densely punctate and predominantly opaque head; long eyes (REL ≥ 0.53, REL2 ≥ 0.73); and relatively short, high petiole (PU ≥ 0.79). Distinctions between it and Pseudomyrmex caeciliae, Pseudomyrmex cubaensis, and Pseudomyrmex urbanusare discussed under those species.

Distribution
This species occurs from Costa Rica to Texas and in Jamaica, and has been introduced into south Florida (Ward 1985). The Florida populations are isolated from the others. It is common in coastal mangroves, and could have arrived in Florida in floating trees. Moreover, Simberloff and Wilson (1969) showed that this species is likely to be a regular and early colonists of isolated mangrove islets, and must therefore have the habit of flying over open water for hundreds, if not thousands of meters. Pseudomyrmex elongatus could have moved around the Gulf when the climate was warmer. On the other hand, colonies can be found in small dead twigs on live trees and shrubs, and the chance of importation in nursery stock is good. The problem of deciding whether a species is exotic is shown by the two species Pseudomyrmex gracilis (an known introduced species) and Pseudomyrmex elongatus, which currently have similar distributions. If P. gracilis had been introduced into Florida just a few decades earlier, before systematic ant surveys, we probably would have concluded that this species was native to the area. (Deyrup, Davis & Cover, 2000.)

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Belize, Bolivia, Brazil, Colombia, Costa Rica, Cuba, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname, Trinidad and Tobago, Venezuela.

It is also found in Paraguay, Ecuador, Brazil, Peru, Venezuela, Suriname, French Guiana, Guyana, Mexico, Guatemala, Honduras, Panama, Costa Rica, Trinidad and Tobago and the United States.

Biology
Ward (1985, 1989) - P. elongatus nests in dead twigs in a variety of woody shrubs and trees. I have collected P. elongatus colonies in twigs of Avicennia germinans, Baccharis halimifolia, Laguncularia racemosa and Rhizophora mangle in Florida, and in Gliricidia sepium, Helicteres, and Inga in Costa Rica and Panama. Among museum material there are records of P. elongatus nesting in a "climbing vine" and "mangrove stems" in Florida, in Quercus virginiana and Prosopis (Texas), and in Quercus fusiformis (Nuevo Leon, Mexico). It has been collected in mangroves, old fields, along roadsides, and in forested habitats ranging from tropical dry forest to secondary and primary rain forest.

Cole (1983) studied the behavior of this ant in red mangroves occurring in southern Florida.

Gillette et al. (2015) in a Chaipas, Mexico field study of twig-nesting ants in coffee plants found C. striatus nesting on plants between 500-1250 m in elevation.

Koch et al. (2018) sampled this species in Caryocar barsiliense trees, in southeastern Brazil cerrado, as part of a study examining species interactions in ant-plants.

Philpot et al. (2018) reported this species was one of the most common ants in an experimental study examining colonization of twigs in shade coffee forests in Chiapas, Mexico (13.3% of the 202 nests found in 796 recovered twigs).

Nomenclature

 *  elongatus. Pseudomyrma elongata Mayr, 1870a: 413 (w.) COLOMBIA. Wheeler, W.M. 1905b: 86 (q.m.); Wheeler, G.C. & Wheeler, J. 1973d: 207 (l.). Combination in Leptalea: Smith, M.R. 1951a: 788; in Pseudomyrmex: Wheeler, G.C. & Wheeler, J. 1956: 384. Senior synonym of tandem: Creighton, 1957b: 18; of alliodorae (and its junior synonym allidora): Ward, 1989: 419. See also: Ward, 1985b: 227; Ward, 1999b: 519.
 * tandem. Pseudomyrma elongata var. tandem Forel, 1906d: 228 (w.) COSTA RICA. Junior synonym of elongatus: Creighton, 1957b: 18.
 * alliodorae. Pseudomyrma alliodorae Wheeler, W.M. 1942: 157, pl. 47, fig. a (w.q.) PANAMA. Wheeler, G.C. & Wheeler, J. 1956: 379 (l.). Combination in Pseudomyrmex: Wheeler, G.C. & Wheeler, J. 1956: 379. Senior synonym of allidora: Brown, 1949a: 42. Junior synonym of elongatus: Ward, 1989: 419.
 * allidora. Pseudomyrma allidora Enzmann, E.V. 1944: 77 (w.) PANAMA. Junior synonym of alliodorae: Brown, 1949a: 42.

Ward (1985): This is the smaller of two elongatus-like species in North America. I am considering it conspecific with P. elongatus Mayr on the basis of (i) the original description of P. elongates, particularly the indication that HL is 1.5 times HW, and (ii) worker material from Costa Rica (leg. Biolley) determined as P. elongatus by Mayr and Forel. There is a confusing variety of elongatus-like forms in Central and South America, which require detailed taxonomic study. Until such a study is carried out, it seems expedient to refer to the North American species as P. elongatus and to leave P. tandem Forel as a provisional synonym.

Pseudomyrmex subater Wheeler & Mann (1914), originally described as a subspecies of P. elongatus, was recognized as a distinct species by Creighton (1955). It may be distinguished from P. elongatus and Pseudomyrmex cubaensis by the shinier integument, conspicuous pilosity (grading insensibly from appressed pubescence to fine suberect and erect setae), broad head (CI 0.83-0.88), short eyes (REL2 0.54-0.58 in P. subater, > 0.62 in P. elongatus and P. cubaensis), distinct petiolar shape (gradually inclined anterior face rounded into a sharply declining posterior fact: so that NI 0.61-0.72), and conspicuous anteroventral tooth on the postpetiole. Apart from two "cotype" workers in the from Haiti, I have seen material of P. subater (misidentifiedd as P. elongatus) from the Bahamas (Andros Island, Nassau) and the same, or a closely related species, from Jamaica (Kingston). Wheeler's (1905) record of "elongatus" from the Bahamas appears to be based on a combination of P. subater and P. cubaensis, judging from material in the MCZ.

Recent collections of P. subater from the Bahamas by Blaine Cole show that this species has striking bright orange queens, which look superficially like those of P. pallidus. Cole also made a collection from a single Cladium culm which contained both 'P. subater' and P. cubaensis workers. These findings suggest that Wheeler's (1905) and Mann's (1920) records of dulotic associations between "flavidula" and "elongata" may have been based in part on pure colonies of 'P. subater', or mixed colonies of 'P. subater' and P. cubaensis.

Worker
Ward (1985) - (n = 24, except for HL, HW, CI, REL, REL2, and PLI, where n = 50): HL 0.78-0.91, HW 0.56-0.64, MFC 0.013-0.024, CI 0.68-0.74, OI 0.52-0.58, REL 0.50-0.58, REL2 0.73-0.82. OOI 0.13-0.48, VI 0.82-0.90, FCI 0.021-0.041, SI 0.42-0.48, SI2 0.55-0.64, FI 0.45-0.56, PDI 0.95-1.45. MPI 0.036-0.072, NI 0.55-0.63, PLI 0.76-0.91, PWI 0.62-0.74, PPWI 1.09-1.40.

A small, brown species with elongate head and eyes (HW 0.56-0.64, CI 0.68-0.74); frontal carinae subcontiguous; occipital margin flat or slightly concave, in full-face dorsal view; basal and declivitous faces of propodeum well differentiated; petiole short, broad, and rounded (PLI 0.76-0.91); postpetiole wider than long. Head densely punctate and usually more or less opaque; remainder of body finely punctate or coriarious-imbricate, varying from opaque to sublucid. Erect pilosity and fine appressed pubescence present on most parts of body, including mesonotum and propodeum; fourth abdominal tergite with a rather dense mat of appressed pubescence.

Type Material
Ward (1989): I found the type worker of P. elongatus, which had previously eluded discovery (Ward, 1985), during a visit to NHMW. It had been misplaced under Pseudomyrmex elongatulus (Daile Torre), a replacement name for the preoccupied P. elongatus (F. Smith, 1877), which is a markedly different species (see Kempf, 1967).

Syntype worker, S. Fe de Bogota, Colombia (Schaufuss) [Examined]; here designated as LECTOTYPE.

Pseudomyrma elongata var. tandem Forel, 1906:228. Syntype workers, EI Hiquito, near San Mateo, Costa Rica (P. Biolley) [Examined].

Pseudomyrma alliodorae Wheeler, 1942: 157. Syntype workers, queen, Ancon, Canal Zone, Panama (W. M. Wheeler) [Examined]. One syntype worker in MCZC here designated LECTOTYPE.

Pseudomyrma allidora Enzmann, 1945:77. Syntype workers, queen, Ancon, Canal Zone, Panama (W. M. Wheeler) (LACM, MCZC) [Examined].

References based on Global Ant Biodiversity Informatics

 * Adams B. J., S. A. Schnitzer, and S. P. Yanoviak. 2016. Trees as islands: canopy ant species richness increases with the size of liana-free trees in a Neotropical forest. Ecography doi: 10.1111/ecog.02608
 * Adams B. J., S. A. Schnitzer, and S. P. Yanoviak. 2019. Connectivity explains local ant community structure in a Neotropical forest canopy: a large-scale experimental approach. Ecology 100(6): e02673.
 * Antoniazzi R., R. N. S. L. Garoo, W. Dattilo, S. P. Ribeiro, and F. S. Neves. 2019. Ant species richness and interactions in canopies of two distinct successional stages in a tropical dry forest. The Science of Nature 106: 20
 * Arruda F. V., M. A. Pesquero, D. G. Marcelino, G. A. Leiter, J. H. C. Delabie, and R. Fagundes. 2015. Size and condition of bamboo as structural factors behind the vertical stratification of the bamboo-nesting ant community. Insectes Sociaux DOI 10.1007/s00040-015-0440-4
 * Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
 * Castano-Meneses, G., M. Vasquez-Bolanos, J. L. Navarrete-Heredia, G. A. Quiroz-Rocha, and I. Alcala-Martinez. 2015. Avances de Formicidae de Mexico. Universidad Nacional Autonoma de Mexico.
 * Chacon de Ulloa P., A. M. Osorio-Garica, R. Achury, and C. Bermudez-Rivas. 2012. Hormigas (Hymenoptera: Formicidae) del Bosque seco tropical (Bs-T) de la cuenca alta del rio Cauca, Colombia. Biota Colombiana 13(2): 165-181.
 * Creighton W. S. 1957. Observations on Pseudomyrmex elongata Mayr (Hymenoptera: Formicidae). J. N. Y. Entomol. Soc. 63: 17-20.
 * Cupul-Magana F. G., and M. Vasquez-Bolanos. 2019. New records of ants (Hymenoptera: Formicidae) from María Cleofas Island, Gulf of California, Mexico. Dugesiana 26(1): 27-29.
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * De la Mora, A., C. J. Murnen, and S. M. Philpott. 2013. Local and landscape drivers of biodiversity of four groups of ants in Neotropical coffee landscapes. Biodiversity and Conservation 22: 871-888.
 * Del Toro, I., M. Vázquez, W.P. Mackay, P. Rojas and R. Zapata-Mata. Hormigas (Hymenoptera: Formicidae) de Tabasco: explorando la diversidad de la mirmecofauna en las selvas tropicales de baja altitud. Dugesiana 16(1):1-14.
 * Emery C. 1895. Beiträge zur Kenntniss der nordamerikanischen Ameisenfauna. (Schluss). Zoologische Jahrbücher. Abteilung für Systematik, Geographie und Biologie der Tiere 8: 257-360.
 * Enzmann E. V. 1944. Systematic notes on the genus Pseudomyrma. Psyche (Camb.) 51: 59-103.
 * Escalante Gutiérrez J. A. 1993. Especies de hormigas conocidas del Perú (Hymenoptera: Formicidae). Revista Peruana de Entomología 34:1-13.
 * Fernández F., E. E. Palacio, W. P. MacKay, and E. S. MacKay. 1996. Introducción al estudio de las hormigas (Hymenoptera: Formicidae) de Colombia. Pp. 349-412 in: Andrade M. G., G. Amat García, and F. Fernández. (eds.) 1996. Insectos de Colombia. Estudios escogidos. Bogotá: Academia Colombiana de Ciencias Exactas, Físicas y Naturales, 541 pp
 * Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
 * Forel A. 1906. Fourmis néotropiques nouvelles ou peu connues. Annales de la Société Entomologique de Belgique 50: 225-249.
 * Forel A. 1912. Formicides néotropiques. Part IV. 3me sous-famille Myrmicinae Lep. (suite). Mémoires de la Société Entomologique de Belgique. 20: 1-32.
 * Franco W., N. Ladino, J. H. C. Delabie, A. Dejean, J. Orivel, M. Fichaux, S. Groc, M. Leponce, and R. M. Feitosa. 2019. First checklist of the ants (Hymenoptera: Formicidae) of French Guiana. Zootaxa 4674(5): 509-543.
 * Garcia Moreno D., R. W. Jones, W. P. Mackay, and P. R. Fernandez. 2003. Diversity and habitat associations of the ants (Insecta: Formicidae) of El Eden Ecological Reserve. In: Gómez-Pompa, A., Allen, M.F., Fedick, S.L., Jiménez-Osornio, J.J. (eds.)The Lowland Maya Area: three millennia at the human-wildland interface. The Haworth Press. New York. Pp. 293-304.
 * Gonzales-Valvidia N. A., G. Gonzales-Escolastico, E. Barba, S. Hernandez-Daumas, and S. Ochoa-Gaona. 2013. Mirmecofauna associated with agroforestry systems in the Mesoamerican Biological Corridor in Tabasco, Mexico. Revista Mexicana de Biodiversidad 84: 306-317.
 * INBio Collection (via Gbif)
 * Ibarra-Manriquez, G., and R. Dirzo. 1990. Plantas mirmecofilas arboreas de la estacion de biologia Los Tuxtlas, Veracruz, Mexico. Revista de Biologia Tropical 38: 79-82.
 * Kempf W. W. 1978. A preliminary zoogeographical analysis of a regional ant fauna in Latin America. 114. Studia Entomologica 20: 43-62.
 * Kempf W. W., and K. Lenko. 1976. Levantamento da formicifauna no litoral norte e ilhas adjacentes do Estado de São Paulo, Brasil. I. Subfamilias Dorylinae, Ponerinae e Pseudomyrmecinae (Hym., Formicidae). Studia Entomologica 19: 45-66.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Kusnezov N. 1963. Zoogeografia de las hormigas en sudamerica. Acta Zoologica Lilloana 19: 25-186
 * Larsen, A., and S. M. Philpott. 2010. Twig-nesting ants: the hidden predators of the coffee berry borer in Chiapas, Mexico. Biotropica 42: 342-347.
 * Longino J. et al. ADMAC project. Accessed on March 24th 2017 at https://sites.google.com/site/admacsite/
 * Maes, J.-M. and W.P. MacKay. 1993. Catalogo de las hormigas (Hymenoptera: Formicidae) de Nicaragua. Revista Nicaraguense de Entomologia 23.
 * Mann W. M. 1916. The Stanford Expedition to Brazil, 1911, John C. Branner, Director. The ants of Brazil. Bulletin of the Museum of Comparative Zoology 60: 399-490
 * Mann W. M. 1920. Additions to the ant fauna of the West Indies and Central America. Bulletin of the American Museum of Natural History 42: 403-439.
 * Menozzi C. 1927. Formiche raccolte dal Sig. H. Schmidt nei dintorni di San José di Costa Rica. Entomologische Mitteilungen. Berlin-Dahlem. 16: 266-277.
 * Menozzi C. 1935. Spedizione del Prof. Nello Beccari nella Guiana Britannica. Hymenoptera-Formicidae. Redia. 21: 189-203.
 * Navarro, E.V. Vergara, H. Echavarria Sanchez, F.J. Serna Cardona. 2007. Hormigas (Hymenoptera: Formicidae) asociadas al arboretum de la Universidad Nacional de Colombia, sede Medellin. Boletín Sociedad Entomológica Aragonesa 40:497-505.
 * Neves F. S., K. S. Queiroz-Dantas, W. D. da Rocha, and J. H. C. Delabie. 2013. Ants of Three Adjacent Habitats of a Transition Region Between the Cerrado and Caatinga Biomes: The Effects of Heterogeneity and Variation in Canopy Cover. Neotrop Entomol 42: 258268.
 * Philpott, S.M. and P.F. Foster. 2005. Nest-site limitation in coffee agroecosytems: Artificial nests maintain diversity of arboreal ants. Ecological Applications 15(4):1478-1485
 * Pires de Prado L., R. M. Feitosa, S. Pinzon Triana, J. A. Munoz Gutierrez, G. X. Rousseau, R. Alves Silva, G. M. Siqueira, C. L. Caldas dos Santos, F. Veras Silva, T. Sanches Ranzani da Silva, A. Casadei-Ferreira, R. Rosa da Silva, and J. Andrade-Silva. 2019. An overview of the ant fauna (Hymenoptera: Formicidae) of the state of Maranhao, Brazil. Pap. Avulsos Zool. 59: e20195938.
 * Reynoso-Campos J. J., J. A. Rodriguez-Garza, and M. Vasquez-Bolanos. 2015. Hormigas (Hymenoptera: Formicidae) de la Isla Cozumel, Quintana Roo, Mexico (pp. 27-39). En: Castaño Meneses G., M. Vásquez-Bolaños, J. L. Navarrete-Heredia, G. A. Quiroz-Rocha e I. Alcalá-Martínez (Coords.). Avances de Formicidae de  México.  UNAM,  Universiad  de  Guadalajara, Guadalajara, Jalisco.
 * Ribas C. R., J. H. Schoereder, M. Pic, and S. M. Soares. 2003. Tree heterogeneity, resource availability, and larger scale processes regulating arboreal ant species richness. Austral Ecology 28(3): 305-314.
 * Ryder Wilkie K.T., A. L. Mertl, and J. F. A. Traniello. 2010. Species Diversity and Distribution Patterns of the Ants of Amazonian Ecuador. PLoS ONE 5(10): e13146.doi:10.1371/journal.pone.0013146
 * Sandoval V. E., and G. Zambrano. 2007. Catálogo de las hormigas presentes en el Museo de Historia Natural de la Universidad del Cauca. Taller Editorial de la Universidad del Cauca, Popayán. 60 pp.
 * Schoereder J. H., T. G. Sobrinho, M. S. Madureira, C. R. Ribas, and P. S. Oliveira. 2010. The arboreal ant community visiting extrafloral nectaries in the Neotropical cerrado savanna. Terrestrial Arthropod Reviews 3: 3-27.
 * Silvestre R., C. R. F. Brandão, and R. R. Silva da 2003. Grupos funcionales de hormigas: el caso de los gremios del cerrado. Pp. 113-148 in: Fernández, F. (ed.) 2003. Introducción a las hormigas de la región Neotropical. Bogotá: Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, xxvi + 424 pp.
 * Smith M. A., W. Hallwachs, D. H. Janzen. 2014. Diversity and phylogenetic community structure of ants along a Costa Rican elevational gradient. Ecography 37(8): 720-731.
 * Vasconcelos, H.L., J.M.S. Vilhena, W.E. Magnusson and A.L.K.M. Albernaz. 2006. Long-term effects of forest fragmentation on Amazonian ant communities. Journal of Biogeography 33:1348-1356
 * Vasquez-Bolanos M. 2011. Checklist of the ants (Hymenoptera: Formicidae) from Mexico. Dugesiana 18(1): 95-133.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Ward P. S. 1985. The Nearctic species of the genus Pseudomyrmex (Hymenoptera: Formicidae). Quaestiones Entomologicae 21: 209-246
 * Ward P. S. 1992. Ants of the genus Pseudomyrmex (Hymenoptera: Formicidae) from Dominican amber, with a synopsis of the extant Antillean species. Psyche (Cambridge) 99: 55-85
 * Ward P. S. 1999. Systematics, biogeography and host plant associations of the Pseudomyrmex viduus group (Hymenoptera: Formicidae), Triplaris- and Tachigali-inhabiting ants. Zoological Journal of the Linnean Society 126: 451-540
 * Ward, P. S. 1989. Systematic Studies on Pseudomyrmecine Ants: Revision of the Pseudomyrmex Oculatus and P. Subtilissimus Species Groups with Taxonomic Comments on Other Species. Questiones Entomologicae 25: 393-468
 * Wheeler W. M. 1905. The ants of the Bahamas, with a list of the known West Indian species. Bulletin of the American Museum of Natural History 21: 79-135.
 * Wheeler W. M. 1908. The ants of Jamaica. Bulletin of the American Museum of Natural History 24: 159-163.
 * Wheeler W. M. 1922. The ants of Trinidad. American Museum Novitates 45: 1-16.
 * Wheeler W. M. 1942. Studies of Neotropical ant-plants and their ants. Bulletin of the Museum of Comparative Zoology 90: 1-262.
 * Wheeler W. M., and I. W. Bailey. 1920. The feeding habits of pseudomyrmine and other ants. Transactions of the American Philosophical Society (2)22: 235-279.
 * Wild, A. L. "A catalogue of the ants of Paraguay (Hymenoptera: Formicidae)." Zootaxa 1622 (2007): 1-55.