Nylanderia of the World, Part IV: Taxonomic contributions to the American Clade I of New World Nylanderia (Hymenoptera: Formicidae) Williams, Jason L. Williams, John F. Lapolla, John S. Lucky, Andrea Zootaxa 2025 2025-01-15 5569 3 549 593 Williams & Williams & Lapolla & Lucky 2025 [151,390,1489,1516] Insecta Formicidae Nylanderia GBIF Animalia Hymenoptera 29 578 Arthropoda species mendax sp. nov.   Figs. 49–51(worker)    Holotype worker,  GUATEMALA: Zacapa, 2km SE La Unión, 14.95039 -89.27894±53m, elev. 1440m, cloud forest, sifted litter,  12.v.2009, cloud forest, sifted litter, LLAMA#Wm-B-03-1-04( USNM: USNMENT01131331).  8paratype workerswith same localitydataasholotype( USNM: USNMENT01131210,  USNMENT01131328,  USNMENT01131329,  USNMENT01131330,  USNMENT01131332;  MNCR: USNMENT01131876,  USNMENT01131877,  USNMENT01131878).   Worker diagnosis:Antennae relatively long, with scapes surpassing posterior margin by nearly half their length; medium to dark reddish-brown with yellow to yellow-brown mandibles, antennae, and leg; meso-and metacoxae about same color or somewhat lighter than mesosoma; moderate to fine cuticular microsculpture resulting in moderate to strong blue iridescence on head, mesosoma, and gaster; erect setae on scapes long and dark, strongly contrasting with appressed pubescence; moderate cephalic pubescence; metatibiae relatively long (HTI> 125).  Compare with:  N. mosaica, N. usul.  WORKER. Measurements (n=6): TL: 2.16–2.52; EL: 0.12–0.14; EW: 0.10–0.11; IOD: 0.32–0.35; HE: 0.00– 0.01; HL: 0.59–0.63; HW: 0.48–0.53; HLA: 0.20–0.23; HLP: 0.24–0.28; SL: 0.70–0.75; PW: 0.36–0.40; MW: 0.19–0.21; PrW: 0.28–0.31; PDH: 0.19–0.26; PTW: 0.12–0.13; LHT: 0.64–0.68; WL: 0.77–0.83; GL: 0.71–1.07; SMC: 11–13; PMC: 2–3; MMC: 2. Indices: BLI: 151–160; CI: 82–85; EPI: 76–95; HTI: 127–134; REL: 20–23; SI: 140–146.  Color: medium to dark reddish-brown with yellow to yellow-brown mandibles, antennae, and leg joints; meso-and metacoxae about same color or somewhat lighter than mesosoma; overall cuticle moderately to finely microsculptured, resulting in moderate to strong blue iridescence on head, mesosoma, and gaster. Pilosity: erect macrosetae on scapes abundant, long, and dark, strongly contrasting with fine, appressed pubescence; moderate cephalic pubescence, found laterally and concentrated around compound eyes; pubescence sparse to absent between compound eyes; 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, with little to no medial emargination; scapes long, surpassing posterior margin by nearly half their length; median ocellus small, but often apparent; lateral ocelli absent or not apparent. Mesosoma: promesonotal area 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.   Etymology:The species epithet is derived from ‘ mendax’ (L. = deceptive), referring to the species’ strong morphological similarity to  N. usul.   Notes:  Nylanderia mendaxworkers most strongly resemble those of  N. usuland are also somewhat like those of  N. mosaica. This species’ overall color, which is medium to dark reddish-brown, is much different than that of  N. mosaica, which is overall yellow to yellow-brown with a medium to dark brown gaster. Both  N. usuland  N. mendaxalso tend to be larger in overall body size than  N. mosaica.  Nylanderia mendaxis most readily separable from  N. usulby the relative length of its scapes, which surpass the posterior margin of the head by nearly half their length. In  N. usul, the scapes are much shorter, only surpassing the posterior margin by a quarter to a third of their length.  Nylanderia mendaxis known from only one locality in Zacapa, Guatemala( Fig. 2B), where it occurs in high elevation cloud forest. 5052389359 cloud forest 2009-05-12 sifted litter USNM Guatemala 1440 14.95039 Zacapa 74 -89.27894 29 578 USNMENT01131331 1 8 Zacapa holotype 5052389353 cloud forest 2009-05-12 sifted litter USNM Guatemala 53 14.95039 La Union 74 -89.27894 29 578 USNMENT01131210 1 1 Zacapa paratype 5052389361 [749,978,1655,1679] cloud forest 2009-05-12 sifted litter USNM Guatemala 53 14.95039 La Union 74 -89.27894 29 578 USNMENT01131328 1 1 Zacapa paratype 5052389358 [978,1207,1655,1679] cloud forest 2009-05-12 sifted litter USNM Guatemala 53 14.95039 La Union 74 -89.27894 29 578 USNMENT01131329 1 1 Zacapa paratype 5052389354 [1208,1436,1655,1679] cloud forest 2009-05-12 sifted litter USNM Guatemala 53 14.95039 La Union 74 -89.27894 29 578 USNMENT01131330 1 1 Zacapa paratype 5052389366 [199,429,1686,1710] cloud forest 2009-05-12 sifted litter USNM Guatemala 53 14.95039 La Union 74 -89.27894 29 578 USNMENT01131332 1 1 Zacapa paratype 5052389340 [435,753,1685,1710] cloud forest 2009-05-12 sifted litter MNCR Guatemala 53 14.95039 La Union 74 -89.27894 29 578 USNMENT01131876 1 1 Zacapa paratype 5052389362 [759,988,1686,1710] cloud forest 2009-05-12 sifted litter USNM Guatemala 53 14.95039 La Union 74 -89.27894 29 578 USNMENT01131877 1 1 Zacapa paratype 5052389335 [994,1233,1686,1710] cloud forest 2009-05-12 sifted litter USNM Guatemala 53 14.95039 La Union 74 -89.27894 29 578 USNMENT01131878 1 1 Zacapa paratype