Nylanderia austroccidua
Creators: name: Williams, Jason L.
name: Williams, John F.
name: Lapolla, John S.
name: Lucky, Andrea
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Formicidae
Nylanderia
Nylanderia austroccidua

description: Nylanderia austroccidua (Trager 1984)
Figs. 5–7 (worker)
Paratrechina austroccidua Trager 1984: 113 (w.q.m.). Holotype worker, U.S.A.: Texas, Boot Springs, Chisos Mts., elev. 2040m, 26.vii.1979, P.S. Ward #3771 (LACM) (examined). 12 paratype workers and 2 paratype males, same locality data as holotype (LACM, MCZC). Combination in Nylanderia: LaPolla et al. 2010: 127.
Worker diagnosis: 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.
Compare with: N. contraria, N. polita
WORKER. Measurements (n=12): TL: 1.66–2.22; EL: 0.11–0.14; EW: 0.09–0.10; IOD: 0.29–0.34; HE: 0.00– 0.03; HL: 0.52–0.61; HW: 0.44–0.52; HLA: 0.17–0.21; HLP: 0.24–0.29; SL: 0.56–0.63; PW: 0.32–0.38; MW: 0.17–0.20; PrW: 0.22–0.28; PDH: 0.18–0.22; PTW: 0.09–0.14; LHT: 0.47–0.55; WL: 0.55–0.72; GL: 0.48–0.95; SMC: 4–7; PMC: 2–3; MMC: 2–3. Indices: BLI: 125–143; CI: 84–85; EPI: 58–79; HTI: 101–110; REL: 19–23; SI: 113–128.
Color: medium to dark brown with yellow to yellow-brown antennae, mandibles, and tarsi; meso- and metacoxae often somewhat lighter than mesosoma; sometimes bicolored with mesosoma lighter than head and gaster; overall cuticle with fine microsculpture resulting in moderate to strong blue iridescence on head and mesosoma. Pilosity: dense cephalic pubescence covering all surfaces of head in full-face view; mesosoma pubescence sparse to absent, limited at most to scattered hairs on pronotum and propodeum, and a fringe of hairs concentrated just posterior to the metanotal groove; gaster pubescence sparse to absent; pair of small, erect setae on apex of petiole. Head: longer than broad and quadrate with distinct posterolateral corners and flattened posterior margin, usually with moderate to strong emargination but sometimes with little to no emargination (HE = 0.00–0.03); scapes surpass posterior margin of head by about a third of their length (SI = 113–128); median ocellus often large and apparent; lateral ocelli small and often absent or not apparent. Mesosoma: promesonotal area flat to evenly convex in profile view, with posterior margin of pronotum continuous or nearly continuous with anterior margin of mesonotum; propodeum low and unevenly rounded, with posterior face about twice as long as dorsal face.
QUEEN. Measurements (n=2): TL: 3.73–4.26; EL: 0.27; HL: 0.76–0.79; HW: 0.67–0.75; SL: 0.77–0.83; WL: 1.25–1.27; GL: 1.71–2.21. Indices: CI: 97–99; REL: 34–36; SI: 102–105.
Relatively large (TL = 3.73–4.26). Color: medium to dark brown with yellow to yellow-brown antennae, mandibles, and tarsi; meso- and metacoxae at most somewhat lighter than mesosoma. Pilosity: most of body covered in moderate to dense pubescence; lacking pubescence on posterior face of propodeum; 1-3 small, erect setae on anepisternum. Head: as broad as long; scapes surpass posterior margin of head by about a third of their length.
MALE. Measurements (n=4): TL: 1.74–2.27; EL: 0.19–0.22; HL: 0.48–0.57; HW: 0.40–0.53; SL: 0.59–0.64; WL: 0.59–0.86; GL: 0.65–0.88. Indices: CI: 83–97; REL: 35–39; SI: 110–122.
Color: medium to dark brown with yellow to yellow-brown antennae, mandibles, and tarsi; meso- and metacoxae at most somewhat lighter than mesosoma. Pilosity: dense pubescence on head, mesoscutum, and mesoscutellum; pubescence sparse to absent on pronotum, anepisternum, katepisternum, propodeum, and gaster; lacking pubescence on posterior face of propodeum. Head: as broad as long; compound eyes surpass lateral margins of head in full-face view; scapes surpass posterior margin of head by about a third of their length. Mesosoma: In profile view, propodeum gently rounded with dorsal face about twice as long as posterior face. Genitalia: gonopod narrow and evenly triangular, with nearly straight edges and apex coming to a point (Fig. 71); in ventral view, ventromedial edge of basivolsella weakly and evenly curved (Fig. 91 of Kallal & LaPolla 2012); gonossiculus straight and only slightly longer than cuspis.
Other material examined: MEXICO: Tamaulipas, El Cielo, Gómez Farías, 23.05216 -99.24252, 7.ix.2019, cloud forest, bait trap, Sandoval-Becerra et al. #MXFOR/0062; Tamaulipas, El Cielo, Gómez Farías, 23.05819 -99.22366, 12.ix.2019, oak-pine forest, hand, Sandoval-Becerra et al. #MXFOR/0102; Tamaulipas, El Cielo, Gómez Farías, 23.0561 -99.2151, 22.x.2019, Sandoval-Becerra et al. #MXFOR/1387; Tamaulipas, El Cielo, Gómez Farías, 23.0561 -99.2151, 22.x.2019, Sandoval-Becerra et al. #MXFOR/1417; Tamaulipas, El Cielo, Gómez Farías, 23.0561 -99.2151, 22.x.2019, Sandoval-Becerra et al. #MXFOR/1433; Tamaulipas, El Cielo, Gómez Farías, 23.0561 -99.2151, 22.x.2019, Sandoval-Becerra et al. #MXFOR/1473; Tamaulipas, El Cielo, Gómez Farías, 23.0521 -99.2425, 7.ix.2019, Sandoval-Becerra et al. #MXFOR/1617; Tamaulipas, El Cielo, Gómez Farías, 23.0486 -99.2455, 8.ix.2019, Sandoval-Becerra et al. #MXFOR/1712; Tamaulipas, El Cielo, Gómez Farías, 23.0521 -99.2425, 7.ix.2019, Sandoval-Becerra et al. #MXFOR/1618; Tamaulipas, El Cielo, Gómez Farías, 23.0486 -99.2455, 8.ix.2019, Sandoval-Becerra et al. #MXFOR/1714; Tamaulipas, El Cielo, Gómez Farías, 23.0455 - 99.2635, 9.ix.2019, Sandoval-Becerra et al. #MXFOR/1739; Tamaulipas, El Cielo, Gómez Farías, 23.0413 -99.2671, 10.ix.2019, Sandoval-Becerra et al. #MXFOR/1781; Tamaulipas, El Cielo, Gómez Farías, 23.0486 -99.2671, 30.x.2019, Sandoval-Becerra et al. #MXFOR/1805; Tamaulipas, El Cielo, Gómez Farías, 30.x.2019, Sandoval-Becerra et al. #MXFOR/1806; Tamaulipas, El Cielo, Gómez Farías, 23.0486 -99.2644, 30.x.2019, Sandoval-Becerra et al. #MXFOR/1810; Tamaulipas, El Cielo, Gómez Farías, 23.0486 -99.2644, 30.x.2019, Sandoval-Becerra et al. #MXFOR/1824; Tamaulipas, El Cielo, Gómez Farías, 23.0462 -99.2649, 31.x.2019, Sandoval-Becerra et al. #MXFOR/1853; Tamaulipas, El Cielo, Gómez Farías, 23.0462 -99.2649, 31.x.2019, Sandoval-Becerra et al. #MXFOR/1856; Tamaulipas, El Cielo, Gómez Farías, 23.04555 -99.26355, pine forest, bait trap, 9.ix.2019, Sandoval-Becerra et al. #MXFOR/0036; Tamaulipas, El Cielo, Gómez Farías, 23.048673 -99.264491, cloud-pine forest, hand, 30.x.2019, Sandoval-Becerra et al. #MXFOR/0939; Tamaulipas, El Cielo, Gómez Farías, 23.05613 -99.21519, deciduous forest, bait trap, 22.x.2019, Sandoval-Becerra et al. #MXFOR/0124; Tamaulipas, El Cielo, Gómez Farías, 23.0581 -99.2236, 12.ix.2019, Sandoval-Becerra et al. #MXFOR/1580; Tamaulipas, El Cielo, Gómez Farías, 23.0561 -99.2151, 22.x.2019, Sandoval-Becerra et al. #MXFOR/1382; Tamaulipas, El Cielo, Gómez Farías, 23.0561 -99.2151, 22.x.2019, Sandoval-Becerra et al. #MXFOR/1465; Tamaulipas, El Cielo, Gómez Farías, 23.0521 -99.2425, 7.ix.2019, Sandoval-Becerra et al. #MXFOR/1635; Tamaulipas, El Cielo, Gómez Farías, 23.0521 -99.2425, 7.ix.2019, Sandoval-Becerra et al. #MXFOR/1674; Tamaulipas, El Cielo, Gómez Farías, 23.0581 -99.2236, 12.ix.2019, Sandoval-Becerra et al. #MXFOR/1564; Tamaulipas, El Cielo, Gómez Farías, 23.0455 - 99.2635, 9.ix.2019, Sandoval-Becerra et al. #MXFOR/1737; U.S.A.: Arizona, Cochise Co., Chiricahua Mts., Pinery Canyon, 6.9km W Onion Saddle, elev. 1890m, 11.viii.1989, S.P. Cover #2092 (SWRS: CASENT0102818); Arizona, Cochise Co., Huachuca Mts., Upper Ramsey Canyon, 31.4333 -110.3167, elev. 1910m, 18.viii.2002, under stone, Quercus / Pinus / Pseudotsuga forest, P.S. Ward #14739 (MCZC: MCZ-ENT00531422).
Notes: Workers of N. austroccidua most closely resemble those of N. contraria and N. 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. 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).
description: Published as part of Williams, Jason L., Williams, John F., Lapolla, John S. & Lucky, Andrea, 2025, Nylanderia of the World, Part IV: Taxonomic contributions to the American Clade I of New World Nylanderia (Hymenoptera: Formicidae), pp. 549-593 in Zootaxa 5569 (3) on pages 557-559, DOI: 10.11646/zootaxa.5569.3.10, http://zenodo.org/record/14734270