Nylanderia pearsei

Identification
This Nylanderia belongs to a cavernicolous, microphthalmic group that includes the Cuban species, Nylanderia myops. It is distinctly larger than this species and the eyes, though small compared with those of other species of the genus, are distinctly larger (those of myops and troglodytes have only 4-5 facets in their greatest diameter) and the conformation of the thorax and petiole is quite different. (Wheeler 1938)

Distribution based on Regional Taxon Lists
Neotropical Region: Mexico.

Nomenclature

 *  pearsei. Nylanderia pearsei Wheeler, W.M. 1938: 254 (w.) MEXICO. Combination in Paratrechina: Brandão, 1991: 367; in Nylanderia: LaPolla, Brady & Shattuck, 2010a: 127.

Worker
Length 2.5-2.7 mm.

Head subrectangular, as broad as long without the clypeus and mandibles and as broad in front as behind, with evenly convex sides, rounded posterior corners and slightly sinuate posterior border. Eyes slightly in front of the middle, small, with only 8-9 facets in their greatest diameter. Mandibles very narrow at the base, with oblique 5-toothed apical borders, the second and fourth tooth smaller than the others. Clypeus convex and subcarinate in the middle, depressed laterally, its anterior border projecting, entire, semicircularly rounded. Frontal area very distinct, small, transversely elliptical; frontal carinae subparallel; frontal groove replaced by a short, linear convexity. Antennae long and slender; scapes extending somewhat more than half their length beyond the posterior border of the head; first funicular joint nearly twice as long as the second, which is twice as long as broad, succeeding joints longer. Thorax elongate; pronotum with neck as long as broad, not convex; mesonotum slightly longer than broad, parallel-sided, rounded behind, flattened or even slightly concave, sloping and bounded by impressed sutures; metanotum distinct, with prominent spiracles which are somewhat farther apart than their diameter; mesoepinotal constriction pronounced; base and declivity of epinotum subequal, the former very convex, the latter flat and sloping; epinotal spiracles projecting. Petiolar scale thick, blunt, strongly inclined forward, its superior border from behind semicircular. Gaster of the usual shape. Legs long and slender.

Shining; sides of head and especially dorsal surface of gaster more opaque, the surface finely reticulate, the gaster more sharply than the remainder of the body.

Pilosity abundant, the stout erect hairs, or macrochaetae pointed, dark brown or blackish, very conspicuous on the dorsal surface, on the legs shorter and white at their tips; seapes with numerous suberect and more delicate white hairs; clypeus, dorsal surface of head and gula with conspicuous long white hairs, which are mingled with the dark macrochaetae on the front. Pubescence white, dilute and conspicuous on the funiculi, gula and sides of head; much finer, denser, more appressed and generally distributed on the remainder of the body and on the legs.

Yellow; appendages scarcely paler; head, clypeus and mandibles slightly reddish; mandibular teeth red.

Type Material
Described from 12 workers from the Muruztun Cave, Tizamin (type-locality), "from a big midden pile of a leaf-cutter mound above cave"; six workers from the Balaam Canche Cave, Chichen Itza, Temple Pool, 260 m. from mouth and six workers from the Chac Mol Cave, Tohil, under stones at top, not mouth.