Nylanderia querna

The nests of this species have consistently been found in acorns, an unusual nesting habitat for Nylanderia, although it remains unclear if they are an exclusive acorn nesting species. Males and queens were collected in acorns in mid-March, and the reproductives probably fly in the early spring as in other Nearctic species. (Kallal & LaPolla, 2012).

Identification
Kallal & LaPolla (2012) - Yellow with dark brown macrosetae, relatively small eyes (REL: 19–27), and sparse head pubescence.

Compare with: Nylanderia arenivaga, Nylanderia guatemalensis, Nylanderia terricola and Nylanderia vividula.

Nylanderia querna is most likely to be misidentified as N. arenivaga. Both are yellow species with dark macrosetae, but N. querna possesses less pubescence, particularly on its head, and has shorter macrosetae. It also lacks the darker gastral tip observed in N. arenivaga. The best way to separate the two species is using males, as N. arenivaga has very distinctive genitalia, including long digiti, whereas N. querna has genitalia very similar to N. faisonensis, N. parvula, and the majority of the Nearctic fauna. This species may also be mistaken for N. vividula or N. terricola, although the worker of N. querna is always uniform yellow (never bicolored). The male of N. querna possesses a yellowish bicolored pattern with a dark brown gaster that is diagnostic for this species, as other Nearctic Nylanderia males tend to be more uniformly brown in color.

Identification Keys including this Taxon

 * Key to Nearctic Nylanderia workers
 * Key to Nearctic Nylanderia males

Distribution
Central United States, including Illinois, Mississippi, and Arkansas.

Distribution based on Regional Taxon Lists
Nearctic Region: United States.

Nomenclature

 *  querna. Nylanderia querna Kallal & LaPolla, 2012: 31, figs. 40-42, 71, 149-156, 198 (w.q.m.) U.S.A.

Worker
Measurements (n=10) TL: 1.97–2.41; HW: 0.45–0.53; HL: 0.54–0.65; EL: 0.10–0.15; SL: 0.51–0.72; PW: 0.31–0.40; WL: 0.60–0.79; GL: 0.79–1.02; PH: 0.18–0.27; PFL: 0.48–0.66; PFW: 0.14–0.17. SMC: 5–14; PMC: 2–3; MMC: 2–3. Indices: CI: 79–98; REL: 19–27; SI: 89–120; FI: 84–115.

Uniformly yellow in color; scapes, mandibles, mesocoxae, and metacoxae same color as mesosoma; cuticle smooth and shiny; cephalic pubescence moderate, becoming denser toward the posterior margin; mesosoma and gastral pubescence virtually absent; macrosetae dark brown. Head ovate; posterior margin emarginated medially; scapes surpass posterior margin by 3–4 funicular segments; ocelli not apparent. Pronotal anterior face greater than 45°; pronotum inflected with shorter pronotal anterior face and longer pronotal dorsal face; anterior margin of mesonotum continuous with pronotal margin; propodeum with short dorsal face and rounded declivitous face.

Queen
Measurements (n=3) TL: 3.41–4.04; HW: 0.68–0.69; HL: 0.69–0.73; EL: 0.23; SL: 0.76–0.79; PW: 0.77–0.89; MW: 0.74–0.76; WL: 1.12–1.26; GL: 1.51–2.07; PH: 0.38–0.46; PFL: 0.62–0.70; PFW: 0.18–0.21. SMC: 6–11; PMC: 3–4; MMC: 10–14; MtMC: 2. Indices: CI: 94–100; REL: 31–34; SI: 108–111; FI: 86–99.

Brown bicolored with lighter, yellowish-brown mesosoma, scapes, mandibles, and legs; cuticle smooth and shiny; body with dense pubescence. Head slightly longer than broad; scapes surpass posterior margins by first 3–4 funicular segments. Propodeum with extremely short dorsal face and long, sloping declivitous face.

Male
Measurements (n=4) TL: 1.89–2.07; HW: 0.47–0.50; HL: 0.49–0.55; EL: 0.18; SL: 0.59–0.63; PW: 0.40–0.49; MW: 0.39–0.47; WL: 0.63–0.80; GL: 0.68–0.81; PH: 0.24–0.32; PFL: 0.48–57; PFW: 0.13–0.15; PL: 0.16–0.23. SMC: 5–12; MMC: 7–11; MtMC: 2. Indices: CI: 91–96; REL: 33–36; SI: 113–119; FI: 97–113.

Bicolored, with brownish-yellow mesosoma, mandibles, scapes, and legs; head and gaster darker brown; mesocoxae and metacoxae sometimes pale yellowish; cuticle smooth and shiny; cephalic pubescence sparse to moderate; mesonotum with dense pubescence; pubescence absent from remainder of mesosoma; gastral pubescence virtually absent. Head slightly longer than broad; eyes weakly convex, scarcely extending beyond lateral margins of the head in full face view; scapes surpass posterior margin by first 3–4 funicular segments; inner mandibular margin long and straight; basal angle approximately 90°; masticatory margin with two denticles and large apical tooth. Mesosoma enlarged to accommodate flight muscles; in lateral view, pronotal margin short and straight; propodeum with equally long dorsal and declivitous faces. Genitalia: parameres laterally oriented, triangular; digiti and cuspides as in faisonensis; digiti slightly shorter than aedeagal valves; cuspides not reaching half the length of digiti; digiti and cuspides with rounded teeth where they meet; aedeagal valve triangular, relatively short, teeth absent; ninth sternite short and broad with thin lateral apodemes.

Etymology
The species epithet querna (L.= of oaks) reflects the fact that collections of this species have almost exclusively come from nests found within acorns.

References based on Global Ant Biodiversity Informatics

 * 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.