Nylanderia austroccidua

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Nylanderia austroccidua
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Lasiini
Genus: Nylanderia
Species: N. austroccidua
Binomial name
Nylanderia austroccidua
(Trager, 1984)

Paratrechina austroccidua casent0102818 profile 1.jpg

Paratrechina austroccidua casent0102818 dorsal 1.jpg

Specimen labels

Nests are frequently found under stones. It is suspected that N. austroccidua follows the reproductive flight schedule of other Nearctic species (Trager, 1984). They are commonly found in moist, mountainous regions of the southwest United States, frequently in forests dominated by oak, maple, and pine. However, there are also collections in arid central Mexico and Texas (fig. 206). This species apparently has the most southern distribution of any native Nearctic Nylanderia species, being known to occur as far south as Costa Rica, where it is a cloud forest inhabitant (Longino, 2010) (Kallal & LaPolla, 2012).

Identification

Williams et al. (2025) - Antennae relatively short, with scapes surpassing posterior margin of head by about a third of their length (SI = 113–128); medium to dark brown and sometimes bicolored with darker head and gaster; antennae, mandibles, leg joints, and tarsi yellow in contrast to body; meso-and metacoxae usually somewhat lighter than mesosoma; fine cuticular microsculpture resulting in moderate to strong blue iridescence on head and mesosoma; dense cephalic pubescence; posterior emargination of head strongly variable, from lacking emargination entirely to deep and notch-like.

Workers of N. austroccidua most closely resemble those of Nylanderia contraria and Nylanderia polita. However, this species can be most readily distinguished from N. contraria by the color of its meso- and metacoxae, which are at most only slightly lighter brown than the rest of the body in N. austroccidua. In contrast, N. contraria has whitish meso- and metacoxae that strongly contrast with the rest of the body, which is dark brown. Nylanderia austroccidua is most readily differentiated from N. polita by the latter’s smooth and shiny surface, which lacks the cuticular microsculpture and blue iridescence that is readily observable under microscopy in all other species of this complex.

Compare with: Nylanderia contraria, Nylanderia polita.

Kallal & LaPolla (2012) - Overall brown, sometimes bicolored with lighter mesosoma than head and gaster; in lateral view pronotal margin angular; bluish reflections visible on head and mesosoma under microscopic examination.

Compare with: Nylanderia bruesii, Nylanderia vividula and Nylanderia terricola.

The bluish hue reflected by the cuticle of this species under microscopic examination is unique among Nearctic species (although some Nylanderia faisonensis may exhibit it weakly and Nylanderia species in other parts of the world do display a similar bluish hue). The angular pronotum viewed in profile distinguishes it from Nylanderia bruesii, Nylanderia terricola, and Nylanderia vividula. Overall body color is generally brown but varies across the range and is not diagnostic; the species ranges from light brown to dark, reddish brown. Bicoloration is also present, but infrequently observed in worker specimens. Mesocoxae and metacoxae are also known to be pale and whitish in some populations. Males have triangular parameres, unlike the more digitiform parameres of N. bruesii, to which this species may be confused, and have a distinct upturned point on the aedeagal valve not present in other species. Trager (1984) noted the presence of subbasal denticles in males, but we have not observed these structures.

Keys including this Species

Distribution

Mountains of southwestern US, Texas, Mexico to Costa Rica.

Williams et al. (2025) - This species does not overlap in range with N. contraria or N. polita and is primarily found in high elevation forests ranging across southwestern North America from central Mexico to Utah (Figs. 2A, 2B).

  • Williams et al. (2025), Fig. 2. Distributions of species: (A) N. austroccidua in the United States and northern Mexico, (B) species found across southern Mexico and Mesoamerica, and (C) N. docilis in South America. Maps were created using GPS coordinates listed in Table S1 and from the Global Ant Biodiversity Informatics (GABI; Guénard et al. 2017) database.

Latitudinal Distribution Pattern

Latitudinal Range: 34.156971° to 10.2°.

   
North
Temperate 		North
Subtropical 		Tropical South
Subtropical 		South
Temperate

Distribution based on Regional Taxon Lists

Nearctic Region: United States (type locality).
Neotropical Region: Costa Rica, Mexico.

Distribution based on AntMaps

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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.
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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.
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Biology

Mackay and Mackay (2002) - This ant nests in the soil, often under a stone. Brood was found in nests in July, callow males and mature females were in nests in July, mature alates in September. Flights occurred in May and July. It nests together with Liometopum apiculatum.

Castes

Photo Gallery

  • Williams et al. (2025), Figs. 5–7. Nylanderia austroccidua worker (USNMENT01131945). Lateral, full-face, and dorsal view of the body.

Nomenclature

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

  • austroccidua. Paratrechina austroccidua Trager, 1984b: 113, fig. 17, 20 (w.q.m.) U.S.A. Combination in Nylanderia: LaPolla, Brady & Shattuck, 2010a: 127. See also: Kallal & LaPolla, 2012: 11.

Type Material

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Kallal & LaPolla (2012) - Measurements (n=15) TL: 1.87–2.64; HW: 0.45–0.60; HL: 0.58–0.69; EL: 0.13–0.18; SL: 0.60–0.76; PW: 0.37–0.45; WL: 0.63–0.84; GL: 0.49–1.25; PH: 0.10–0.30; PFL: 0.47–0.61; PFW: 0.13–0.19. SMC: 2–9; PMC: 2–5; MMC: 1–4. Indices: CI: 82–90; REL: 21–28; SI: 109–114; FI: 81–96.

Brown in color, infrequently bicolored with mesosoma lighter brown than head and gaster; mandibles, scapes, mesocoxae, metacoxae, and legs yellowish-brown; cuticle smooth and shiny; cephalic pubescence dense; pronotal pubescence sparse to virtually absent on remainder of mesosoma; gastral pubescence sparse; on mesosoma notum macrosetae often with raised setal bases. Head relatively quadrate with slightly convex lateral margins; posterior margin slightly emarginated medially; scapes surpass posterior margin by first 3–4 funicular segments; median ocellus apparent, lateral ocelli often apparent. Pronotal anterior face greater than 45°; pronotal anterior face shorter than pronotal dorsal face; pronotal dorsal face with unique concavity; anterior margin of mesonotum continuous with posterior pronotal margin; propodeum with short dorsal face and long declivitous face, sometimes slightly dome-like in larger specimens.

Queen

Kallal & LaPolla (2012) - Measurements (n=2) TL: 3.73-4.26; HW: 0.75-0.67; HL: 0.76-0.79; EL: 0.27; SL: 0.77-0.83; PW: 0.88-0.95; MW: 0.82–0.85; WL: 1.25-1.27; GL: 1.71-2.21; PH: .41-0.42; PFL: 0.72-0.76; PFW: 0.20-0.21. SMC: 1-6; PMC: 6-8; MMC: 14-20; MtMC: 2-7. Indices: CI: 97-99; REL: 34-36; SI: 102-105; FI: 95-96.

Overall brown in color with mandibles, leg joints, and tarsi yellowish-brown; cuticle smooth and shiny; body with dense pubescence; macrosetae dark brown. Head as broad as long; scapes surpass posterior margin by length of first 3–4 funicular segments. Propodeum with short dorsal face and steep, long declivitous face.

Male

Kallal & LaPolla (2012) - Measurements (n=4) TL: 1.74–2.27; HW: 0.40–0.53; HL: 0.48–0.57; EL: 0.19–0.22; SL: 0.59–0.64; PW: 0.55; MW: 0.42–0.52; WL: 0.59–0.86; GL: 0.65–0.88; PH: 0.24–0.33; PFL: 0.47–0.54; PFW: 0.11–0.15; PL: 0.18–0.30. SMC: 0–4; MMC: 4–7; MtMC: 1–3. Indices: CI: 83–97; REL: 35–39; SI: 110–122; FI: 84–101.

Overall brown with mesocoxae, metacoxae, leg joints, and tarsi yellowish-brown; cuticle smooth and shining; cephalic pubescence moderate to dense; mesonotum with dense pubescence; gaster pubescence virtually absent; macrosetae dark brown. Head as broad as long; eyes weakly convex, slightly extending beyond lateral margins of the head in full face view; scapes surpass posterior margin by length of first two funicular segments; mandibles with long, straight inner mandibular margin; basal angle approximately 90°; smooth masticatory margin with a small subapical tooth and large apical tooth. Mesosoma enlarged to accommodate flight muscles; in lateral view, pronotal margin short and relatively straight with a small inflection towards mesonotal margin; propodeum with long dorsal face and short declivitous face. Genitalia: parameres short, relatively narrow, laterally oriented, and triangular; digiti angled ventrally at approximately half its length, with teeth at that angle where they meet cuspides; aedeagal valves triangular with small concavity at the distal end of the ventral margin, resulting a curved tip, teeth absent; ninth sternite somewhat rectangular, with thin lateral apodemes.

References

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
  • 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.
  • Johnson R. Personnal Database. Accessed on February 5th 2014 at http://www.asu.edu/clas/sirgtools/resources.htm
  • Kallal R. J, and J. S. Lapolla. 2012. Monograph of Nylanderia (Hymenoptera: Formicidae) of the world, part II: Nylanderia in the Nearctic. Zootaxa 3508: 1-64.
  • Longino J. et al. ADMAC project. Accessed on March 24th 2017 at https://sites.google.com/site/admacsite/
  • Mackay W. P. and Mackay, E. E. 2002. The ants of New Mexico (Hymenoptera: Formicidae). Lewiston, New York: Edwin Mellen Press, 400 pp.
  • 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.
  • Varela-Hernandez, F., M. Rocha-Ortega, W. P. Mackay, and R. W. Jones. 2016. Lista preliminar de las hormigas (Hymenoptera: Formicidae) del estado de Queretaro, Mexico. Pages 429-435 in . W. Jones., and V. Serrano-Cardenas, editors. Historia Natural de Queretaro. Universidad Autonoma de Queretaro, Mexico.
  • Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
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