Neivamyrmex leonardi

This species is primarily subterranean and raids nests of Pheidole obtusospinosa. Snelling and Snelling (2007) - This is a poorly known species. The synonymous form N. peninsulare was described from a few workers taken under a stone. Watkins (1971) also reported finding it under a stone in Texas and “...observed a few workers...in a weak nocturnal raiding column of N. opacithorax...” Our specimens from 9-mile Canyon were found in soft sand at a depth of about 45 cm. This was in Sagebrush Desert with some intermixed Larrea. This ant has also been collected from Creosote Bush Scrub-Joshua Tree Woodland. In the chaparral biome of Deep Canyon, Wheeler and Wheeler (1973) found a nest under a slightly buried stone. Mann (1925) described the staphylinid beetle Pulicomorpha coecum from specimens collected with a colony of N. leonardi (as Eciton peninsularis Mann) in Baja California Sur, Mexico.

Identification
Smith (1942)- The worker of leonardi can be distinguished by the short scape; broad flange in front of antennal socket; shape of mandible; subrectangular petiole; smooth and shining body with the exception of certain parts; and its light yellowish-brown color. It is also characterized by the apparent absence of eyes, and by the lack of a pronotal carina.

The worker of this very small species is most closely related to that of Neivamyrmex pauxillus, from which it can be distinguished by its shorter and more robust head, the posterior region of which is not so noticeably constricted as that of pauxillum; by the presence of a broad, distinct flange in front of the antennal socket; its larger size; and by the lack of a distinctly flattened gaster. Furthermore, leonardi has been collected only in the southern part of California whereas pauxillum has been found only in central and southwestern Texas.

Distribution
United States: Oklahoma and Texas, west to California and Nevada; Mexico, Baja California Sur and Tamaulipas south to Guerrero.

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Mexico.

Castes
The queen and male forms are unknown; however based on range data we surmise that Neivamyrmex minor is probably the male form of N. leonardi. (Snelling and Snelling 2007)

Nomenclature

 *  leonardi. Eciton (Acamatus) leonardi Wheeler, W.M. 1915b: 392 (w.) U.S.A. Combination in E. (Neivamyrmex): Smith, M.R. 1942c: 570; in Neivamyrmex: Borgmeier, 1953: 10. Senior synonym of peninsulare: Borgmeier, 1955: 431. See also: Snelling, G.C. & Snelling, R.R., 2007: 477.
 * peninsulare. Eciton (Acamatus) peninsulare Mann, 1926: 98 (w.) MEXICO. Combination in Neivamyrmex: Borgmeier, 1953: 10. Junior synonym of leonardi: Borgmeier, 1955: 431.

Worker
Smith (1942) - Length 2-3 mm.

Head slightly longer than broad; a little broader anteriorly than posteriorly, with emarginate posterior border and moderately convex sides. Eye apparently absent. Superior border of mandible with basal tooth and an excised margin between this tooth and masticatory border, the excised margin sometimes with a few very small, irregular denticulae; masticatory border with a long apical and two shorter teeth. Antennal scape fairly robust, short, attaining approximately one-half length of head; all segments of funiculus except first and last as broad as or broader than long. Frontal carina forming a broad, pellucid flange in front of antennal socket. Posterior corners of head, from above, feebly produced, bluntly angular. Thorax, from above, with a distinct constriction on each side of meso-epinotal region. Pronotum without any evident transverse carina. Dorsum of thorax weakly convex; promesonotum feebly elevated above epinotum, meso-epinotal suture feebly developed. Petiole and postpetiole each with a ventral tooth-like projection. Petiole subquadrate, approximately one and one-fourth times as long as broad. Postpetiole slightly shorter, but distinctly broader, than petiole; approximately two-thirds as long as broad, subtrapezoidal. Gaster oval.

Body and appendages smooth and shining with the following exceptions: Mandibles, funiculi, meso- and matapleura, meso-epinotal constriction, tarsi, and ventral surfaces and sides of petiole and postpetiole, subopaque; mandibles coarsely striate-punctate; all areas faintly shagreened except funiculi and tarsi. Head with sparse but definite punctures.

Hairs pale yellowish, moderately long, and moderately abundant, suberect to erect.

Light yellowish brown with darker clypeal region and mandibles.

Type Material
Smith (1942) - Point Loma, near San Diego, Calif., Percy Leonard. Cotypes in Museum of Comparative Zoology.

References based on Global Ant Biodiversity Informatics

 * Cover S. P., and R. A. Johnson. 20011. Checklist of Arizona Ants. Downloaded on January 7th at http://www.asu.edu/clas/sirgtools/AZants-2011%20updatev2.pdf
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Fernandes, P.R. XXXX. Los hormigas del suelo en Mexico: Diversidad, distribucion e importancia (Hymenoptera: Formicidae).
 * Hernandez, F. Varela and G. Castano-Meneses. 2010. Checklist, Biological Notes and Distribution of Ants (Hymenoptera: Formicidae) from Barranca de Metztitlán Biosphere Reserve, Hidalgo, Mexico. Sociobiology 56(2):397-434
 * Johnson R. Personnal Database. Accessed on February 5th 2014 at http://www.asu.edu/clas/sirgtools/resources.htm
 * Johnson, R.A. and P.S. Ward. 2002. Biogeography and endemism of ants (Hymenoptera: Formicidae) in Baja California, Mexico: a first overview. Journal of Biogeography 29:10091026/
 * Mackay, W.P. and E. Mackay. XXXX. The Ants of New Mexico
 * Mallis A. 1941. A list of the ants of California with notes on their habits and distribution. Bulletin of the Southern California Academy of Sciences 40: 61-100.
 * O'Keefe S. T., J. L. Cook, T. Dudek, D. F. Wunneburger, M. D. Guzman, R. N. Coulson, and S. B. Vinson. 2000. The Distribution of Texas Ants. The Southwestern Entomologist 22: 1-92.
 * Pape R. B., and B. M. O'connor. 2014. Diversity and ecology of the macro-invertebrate fauna (Nemata and Arthropoda) of Kartchner Caverns, Cochise County, Arizona, United States of America. Checklist 10(4): 761-794.
 * Snelling G. C. and R. R. Snelling. 2007. New synonymy, new species, new keys to Neivamyrmex army ants of the United States. Memoirs of the American Entomological Institute 80: 459-550
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Watkins II, J.F. 1982.The army ants of Mexico (Hymenoptera: Formicidae: Ecitoninae). Journal of the Kansas Entomological Society 55(2): 197-247.
 * Watkins J. F., II 1971. A taxonomic review of Neivamyrmex moseri, N. pauxillus, and N. leonardi, including new distribution records and original descriptions of queens of the first two species. Journal of the Kansas Entomological Society 44: 93-103.
 * Wheeler G. C., and J. Wheeler J. 1989. A checklist of the ants of Oklahoma. Prairie Naturalist 21: 203-210.
 * Wheeler, G.C. and J. Wheeler. 1985. A checklist of Texas ants. Prairie Naturalist 17:49-64.