Pseudomyrmex mordax

Pseudomyrmex mordax nest in Tachigali plants.

Identification
Ward (1999) - P. mordax can be distinguished from Pseudomyrmex triplarinus and Pseudomyrmex dendroicus by the relatively short legs and denser head sculpture. It is also smaller in size than these two species, the difference being absolute in queens (queen HW 1.20–1.41 and queen LHT 0.95–1.09, compared to > 1.45 and > 1.18, respectively, in the other two species). P. mordax differs from P. triplaridis by the better separated frontal carinae (worker PFC/ASD 0.64–0.75 and queen PFC/ASD 0.71–0.82, compared with 0.54–0.65 and 0.62–0.71, respectively, in P. triplaridis), absence of standing pilosity on the posterior margin of the head (in frontal view), subrectangular or subtriangular anteroventral petiolar process that is not recurved posteroventrally, and lighter color; and from Pseudomyrmex ultrix by the narrower petiole (compare worker PWI and PLI values; queen PWI 0.72–0.83, compared to 0.93–0.99 in P. ultrix), absence of pilosity on posterior margin of head, and lack of an angular protuberance on the worker propodeum.

Distribution
Colombia, Panama and Venezuela.

Distribution based on Regional Taxon Lists
Neotropical Region: Colombia, Panama, Venezuela.

Biology
Ward (1999) - Among other Triplaris-inhabiting ants in the viduus group it overlaps in distribution only with Pseudomyrmex viduus and, marginally, Pseudomyrmex dendroicus. Forel (1904a) gives details on the biology of P. mordax in the Santa Marta region of Colombia, under the name Pseudomyrma arboris-sanctae race symbiotica. Based on his observations in the Canal Zone, Panama, Wheeler (1942:58) concluded that P. mordax was not very effective at excluding alien (unspecialized) ants from Triplaris, and he commented that this species, “though a very vicious and aggressive ant, seems not to sting as severely as the Pseudomyrmas inhabiting T. surinamensis, Tachigali paniculata and the bull-horn Acacias”. Additional information on P. mordax is provided by Schremmer (1984), who studied two species of Triplaris-associated Pseudomyrmex in Colombia but mistook them for a single species (identified as P. triplarinus). His observations from Since, Departmento Sucre refer to P. mordax, while those from Villavicencio refer to P. dendroicus. Jaffe et al. (1986) investigated worker recruitment, territorial marking, nestmate recognition and alarm behaviour in laboratory colonies of P. mordax (identified as P. triplarinus symbioticus). Triplaris cumingiama Fischer & Meyer ex C. A. Meyer is the host of P. mordax in Panama and in at least parts of Colombia. The ant has also been reported from Triplaris americana in Venezuela (Jaffe et al., 1986, as T. felipensis).

Nomenclature

 *  mordax. Pseudomyrma mordax Warming, 1894: 173 (attributed to Meinert) (w.) VENEZUELA. Combination in Pseudomyrmex: Ward, 1999b: 497. Senior synonym of symbiotica and material of the unavailable names loewensohni, panamensis referred here: Ward, 1999b: 497.
 * symbiotica. Pseudomyrma arborissanctae r. symbiotica Forel, 1904c: 38 (w.m.) COLOMBIA. Combination in Pseudomyrmex: Kempf, 1961a: 401. Subspecies of triplarinus: Wheeler, W.M. & Darlington, 1930: 109; Wheeler, W.M. 1942: 189. Junior synonym of mordax: Ward, 1999b: 497.

Ward (1999) - The name P. mordax has languished in the literature since its original appearance (Warming, 1894). Fortunately, examples of the specimens to which Warming referred (from Las Trincheras, Venezuela) are in the Forel collection in Geneva, and this secures the identity of P. mordax and allows designation of a lectotype.

Worker
Ward (1999) - Measurements (n=18). HL 1.03–1.30, HW 0.99–1.19, MFC 0.100–0.130, LHT 0.77–0.95, CI 0.92–0.98, REL 0.41–0.44, REL2 0.44–0.47, FCI 0.10–0.12, SI 0.42–0.45, FLI 1.47–1.87, FI 0.37–0.42, PLI 0.77–0.94, PWI 0.82–0.93, PPWI 1.32–1.66.

Similar to Pseudomyrmex triplarinus (q.v.) except as follows. Averaging smaller in size. Profemur tending to be broader (compare FI values). Legs shorter in relation to body size and eye length (LHT/HL 0.70–0.74, EL/LHT 0.57–0.60 compared to 0.78–0.93 and 0.48–0.55, respectively, in P. triplarinus). Anteroventral petiolar process well developed, subrectangular or bluntly triangular, usually not directed posteroventrally. Punctures on head coarser and denser, especially on upper half of head between compound eye and ocellar triangle, where punctures are mostly 0.010–0.015mm in diameter and separated by about their diameters. Standing pilosity less dense on average (MSC 25–56, HTC 5–11), absent from the posterior margin of the head (frontal view). Body colour tending to be lighter, but varying from light yellow- or orange-brown to medium brown, the gaster sometimes darker than the rest of the body.

Type Material
Ward (1999) :

Syntype workers, queens, Las Trincheras, Venezuela (Meinert) [Examined]. One worker here designated Lectotype.

Pseudomyrma arboris-sanctae race symbiotica Forel, 1904a:38. Syntype workers, males, Dibulla, Colombia (A. Forel) (,, , , MHNG, , , ) [Examined]. One syntype worker in MHNG here designated Lectotype.

Pseudomyrma arboris-sanctae race symbiotica var. panamensis Forel, 1912:22. Workers, queens, males, Panama (Christophersen) (MHNG) [Examined].

References based on Global Ant Biodiversity Informatics

 * Enzmann E. V. 1944. Systematic notes on the genus Pseudomyrma. Psyche (Camb.) 51: 59-103.
 * 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. 1904. Miscellanea myrmécologiques. Rev. Suisse Zool. 12: 1-52.
 * Forel A. 1912. Formicides néotropiques. Part IV. 3me sous-famille Myrmicinae Lep. (suite). Mémoires de la Société Entomologique de Belgique. 20: 1-32.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * 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
 * Wheeler W. M. 1942. Studies of Neotropical ant-plants and their ants. Bulletin of the Museum of Comparative Zoology 90: 1-262.