Nylanderia contraria Williams, Williams, Lapolla & Lucky, 2025, sp. nov.
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 contraria

description: Nylanderia contraria, sp. nov.
Figs. 17–19 (worker); Figs. 20–21 (queen); Figs. 22–25 (male)
Holotype worker, MEXICO: Oaxaca, Cafetal Carlota, 18.04802 -96.69164 ±30m, elev. 1028m, 12.vi.2016, liquidambar/ cloud forest, sifted litter, R.S. Anderson #RSA2016-136 (USNM: USNMENT01130973). 5 paratype workers, 3 paratype queens, and 2 paratype males with same locality data as holotype (USNM: USNMENT01131808, USNMENT01131970, USNMENT01131971, USNMENT01131974, USNMENT01131975, USNMENT01131977; MNCR: USNMENT01131972, USNMENT01131973, USNMENT01131976, USNMENT01131978).
Worker diagnosis: Antennae relatively short, with scapes surpassing posterior margin of head by about a third of their length; dark brown, with antennae, mandibles, leg joints, and tarsi yellow in contrast to body; meso-and metacoxae whitish, strongly contrasting with mesosoma; fine cuticular microsculpture resulting in moderate to strong blue iridescence on head and mesosoma; dense cephalic pubescence; posterior margin of head slightly to moderately emarginate.
Compare with: N. austroccidua, N. polita.
WORKER. Measurements (n=11): TL: 1.67–2.19; EL: 0.10–0.12; EW: 0.08–0.09; IOD: 0.26–0.33; HE: 0.01; HL: 0.52–0.58; HW: 0.43–0.50; HLA: 0.18–0.20; HLP: 0.23–0.27; SL: 0.55–0.62; PW: 0.29–0.36; MW: 0.17–0.20; PrW: 0.23–0.26; PDH: 0.12–0.21; PTW: 0.10–0.24; LHT: 0.45–0.51; WL: 0.58–0.68; GL: 0.57–0.95; SMC: 5–7; PMC: 2–3; MMC: 2. Indices: BLI: 130–144; CI: 81–85; EPI: 69–78; HTI: 101–109; REL: 18–22; SI: 118–132.
Color: dark brown with yellow to yellow-brown antennae, mandibles, leg joints, and tarsi; meso- and metacoxae whitish, strongly contrasting with rest of body; 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 slight to moderate emargination; scapes surpass posterior margin of head by about a third of their length; 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 evenly rounded, with posterior face at most slightly longer than dorsal face.
QUEEN. Measurements (n=3): TL: 3.36–3.61; EL: 0.18–0.19; HL: 0.62–0.64; HW: 0.62–0.63; SL: 0.62–0.64; WL: 1.03–1.10; GL: 1.70–1.90. Indices: BLI: 164–177; CI: 97–100; REL: 29–30; SI: 100–102.
Moderately sized. Color: Medium to dark brown, with whitish meso- and metacoxae. Pilosity: most of body covered in moderate to dense pubescence; lacking pubescence on posterior face of propodeum; 1-4 small, erect setae on anepisternum.
MALE. Measurements (n=2): TL: 1.90–1.95; EL: 0.16; HL: 0.47; HW: 0.41–0.43; SL: 0.51–0.52; WL: 0.66– 0.69; GL: 0.77–0.79. Indices: BLI: 152–167; CI: 88–91; REL: 33–35; SI: 121–123.
Color: medium to dark brown with yellow to yellow-brown antennae, mandibles, and tarsi; whitish meso- and metacoxae. Pilosity: dense pubescence on head, mesoscutum, and mesoscutellum; pubescence sparse to absent on pronotum, anepisternum, katepisternum, propodeum, and gaster. 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 and evenly rounded, with dorsal face about as long as posterior face. Genitalia: gonopod narrow and triangular, with apex coming to a point and slightly turned upward (Fig. 71); in ventral view, ventromedial edge of basivolsella strongly angled at base and sloping laterally toward cuspis (Fig. 24); gonossiculus mostly straight and about twice as long as cuspis.
Other material examined: MEXICO: Veracruz, 8km WSW Xalapa, 19.52123 -96.99372 ± 100m, elev. 1570m, 24.vi.2016, cloud forest, baiting, ADMAC#Ba-F-05-4-01-11; Oaxaca, Cafetal Carlota, 18.0479 -96.69193 ± 30m, elev. 1021m, 12.vi.2016, liquidambar/cloud forest, sifted litter, R.S. Anderson #RSA2016-137; Oaxaca, Cafetal Carlota, 18.04756 -96.69252 ± 30m, elev. 1011m, 12.vi.2016,, liquidambar/cloud forest, sifted litter, R.S. Anderson #RSA2016-138; Oaxaca, Cafetal Carlota, 18.04773 -96.68953 ± 30m, elev. 1041m, 14.vi.2016, liquidambar/cloud forest, sifted litter, R.S. Anderson #RSA2016-145; Oaxaca, Cafetal Carlota, 18.04784 -96.69198 ± 30m, elev. 1019m, 14.vi.2016, liquidambar/cloud forest, sifted litter, R.S. Anderson #RSA2016-146; Oaxaca, above Cafetal Carlota, 18.05241 -96.69106 ± 30m, elev. 1374m, 14.vi.2016, mixed hardwood forest, sifted litter, R.S. Anderson #RSA2016-148; Oaxaca, above Cafetal Carlota, 18.05367 -96.69183 ± 30m, elev. 1459m, 14.vi.2016, mixed hardwood forest, sifted litter, R.S. Anderson #RSA2016-149; Oaxaca, above Cafetal Carlota, 18.05419 -96.69207 ± 30m, elev. 1508m, 14.vi.2016, mixed hardwood forest, sifted litter, R.S. Anderson #RSA2016-150; Oaxaca, near Cerro 71, 18.11476 -96.76884 ± 30m, elev. 1437m, 15.vi.2016, mixed hardwood forest, sifted litter, R.S. Anderson #RSA2016-152; Oaxaca, Agua de Hueso, 18.14653 -96.7934 ± 30m, elev. 1915m, 15.vi.2016, scrubby cloud forest, sifted litter, R.S. Anderson #RSA2016-153; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04847 -96.69065 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-1-18; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04879 -96.69065 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa- F-04-1-25; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04892 -96.69065 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-1-28; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04901 -96.69065 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-1-30; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.0486 -96.6907 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-1-32; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.0486 -96.69101 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-1-38; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.0486 -96.69106 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-1-39; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.0486 -96.69116 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-1-41; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.0486 -96.69121 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-1-42; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.0486 -96.69132 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa- F-04-1-44; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.0486 -96.69147 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-1-47; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04736 -96.6903 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-2-01; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04745 -96.69018 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-2-04; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04748 -96.69014 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-2-05; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04756 -96.69002 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa- F-04-2-08; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04759 -96.68999 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-2-09; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04762 -96.68995 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-2-10; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04765 -96.68991 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-2-11; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04804 -96.68954 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-2-24; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04818 -96.68967 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa- F-04-2-28; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04825 -96.68974 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-2-30; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04828 -96.68977 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-2-31; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04835 -96.68984 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-2-33; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04839 -96.68987 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-2-34; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04846 -96.68994 ± 20m, 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-2- 36; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04846 -96.69027 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-2-46; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.04835 -96.69037 ± 20m, elev. 1040m, 13.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wa-F-04-2-49; Veracruz, 8km WSW Xalapa, 19.5213 -96.99184 ± 20m, elev. 1520m, 22.vi.2016, cloud forest, sifted litter, ADMAC#Wa-F-05-1-25; Veracruz, 8km WSW Xalapa, 19.52107 -96.99216 ± 20m, elev. 1530m, 22.vi.2016, cloud forest, sifted litter, ADMAC#Wa- F-05-1-33; Veracruz, 8km WSW Xalapa, 19.52092 -96.99236 ± 20m, elev. 1530m, 22.vi.2016, cloud forest, sifted litter, ADMAC#Wa-F-05-1-38; Veracruz, 8km WSW Xalapa, 19.5219 -96.99063 ± 20m, elev. 1500m, 22.vi.2016, cloud forest, sifted litter, ADMAC#Wa-F-05-2-09; Veracruz, 8km WSW Xalapa, 19.52245 -96.99086 ± 20m, elev. 1500m, 22.vi.2016, cloud forest, sifted litter, ADMAC#Wa-F-05-2-22; Chiapas, 5km NE Coapilla, 17.17602 - 93.13293 ± 300m, elev. 1990m, 25.v.2008, mesophil forest, sifted litter, LLAMA#Wm-A-04-1; Oaxaca, 1km E San Jerónimo Tecoatl, 18.16841 -96.90282 ± 10m, elev. 1800m, 12.vi.2016, 2° alder forest, sifted litter, ADMAC#Wm- F-04-1-02; Oaxaca, 1km SE Huautla, 18.12357 -96.83419 ± 10m, elev. 1650m, 12.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wm-F-04-1-03; Oaxaca, 6km WNW Ayautla, 18.05281 -96.72518 ± 10m, elev. 1570m, 12.vi.2016, 2° mixed hardwood forest, sifted litter, ADMAC#Wm-F-04-1-04; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.05175 -96.69096 ± 20m, elev. 1320m, 14.vi.2016, 2° wet forest, sifted litter, ADMAC#Wm-F-04-1-06; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.05369 -96.69192 ± 20m, elev. 1460m, 14.vi.2016, 2° wet forest, sifted litter, ADMAC#Wm-F-04-1-07; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.05543 -96.69253 ± 20m, elev. 1610m, 14.vi.2016, montane wet forest, sifted litter, ADMAC#Wm-F-04-1-08; Oaxaca, Cafetal Carlota, 3km NW Ayautla, 18.05602 -96.69274 ± 20m, elev. 1660m, 14.vi.2016, montane wet forest, sifted litter, ADMAC#Wm-F-04- 1-09; Oaxaca, 5km ENE Huautla, 18.14453 -96.79799 ± 20m, elev. 1890m, 15.vi.2016, 2° liquidambar forest, sifted litter, ADMAC#Wm-F-04-2-02; Veracruz, 8km WSW Xalapa, 19.52265 -96.9909 ± 125m, elev. 1500m, 22.vi.2016, cloud forest, sifted litter,ADMAC#Wm-F-05-2-01; Veracruz, Las Cañadas, 19.18823 -96.99155 ± 20m, elev. 1410m, 1.vii.2016, montane wet forest, sifted litter, ADMAC#Wm-F-07-1-06; Veracruz, Las Cañadas, 19.19018 -96.99164 ± 20m, elev. 1400m, 1.vii.2016, montane wet forest, sifted litter, ADMAC#Wm-F-07-1-08.
Etymology: The species epithet is derived from ‘ contrarius ’ (L. = contrary), referring to the strong color contrast observed in this species between the white meso- and metacoxae and the medium to dark brown of the rest of the body.
Notes: While the overall habitus of N. contraria workers most strongly resembles that of N. austroccidua and N. polita workers, they are most readily distinguished from both of those species by the stark contrast in color between its whitish meso- and metacoxae and dark brown mesosoma. This species is more likely to be confused with N. austroccidua, as these two species have similar cuticular microsculpture that causes a similar amount of blue iridescence, which N. polita lacks entirely. Nylanderia contraria can be found in moderate to high elevation forests in southern Mexico, and its known range is limited to the states of Oaxaca and Veracruz (Fig. 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 562-566, DOI: 10.11646/zootaxa.5569.3.10, http://zenodo.org/record/14734270