Simopelta andersoni

Identification
The large eye and the four mandibular teeth would separate this species from all of the others in the genus Simopelta . It would be most likely confused with the large eyed Simopelta oculata, which only has three mandibular teeth. The transverse striae or rugulae on the dorsum of the head could result in confusion with S. transversa and similar species, all of which have three mandibular teeth. Additionally, the top of the petiolar node has distinct, transverse striae, the top of the node of S. transversa  has an indistinct, granulate sculpture.

It is closely related to Simopelta quadridentata, but differs in a number of consistent characteristics. The eye is larger, the subpetiolar process is more elongated (length at bottom of lobe > 0.1 mm, versus < 0.1 mm in S. quadridentata) and the same depth over the length (wider posteriorly in S. quadridentata). The upper part of the node of the petiole has vertical striae, which then pass transversely over the top of the node. The node of S. quadridentata has mostly horizontal striae, which encircle the node and isolate the similar transverse striae. The long, lobed process over the clypeal apron could cause confusion with Simopelta longirostris. They can be easily separated, as S. andersoni has four mandibular teeth, S. longirostris has three.

Distribution based on Regional Taxon Lists
Neotropical Region: Costa Rica.

Habitat
Mountainous regions from 200-1200m elevation. This species occurs in mature montane forest habitats, with highest density around 1000m elevation.

Nomenclature

 *  andersoni. Simopelta andersoni Mackay & Mackay, 2008: 296, figs. 6, 25, 27, 28 (w.) COSTA RICA.

Worker
The worker of this species can be characterized by the large eye (maximum diameter 0.10-0.14 mm), composed of a single ommatidium, and located about 1½ diameters from the anterior margin of the head, and the four toothed mandible. It is a moderately large (total length about 5 mm), dark reddish brown species, with transverse rugulae on the dorsum of the head. The head length ranges from 0.99 - 1.03 mm, the head width 0.74-0.82. The anterior margin of clypeus is moderately acute, but does not form a spine. The scape (0.96-1.06 mm) extends about 1/3 length past the posterior lateral corner of the head. The anterior border of the mesonotum is distinctly lower than the posterior edge of pronotum; the mesonotum to the anterior part of propodeum is concave. The anterior and posterior faces of the petiole are nearly parallel, and straight, and a well-developed, flattened, dorsal face is present. The spiracular horns (Figure 27) of the petiole are well developed. The subpetiolar process is rectangular shaped; the posterior face of the process is only slightly concave.

Erect hairs are sparse, and are present on the clypeus, mandibles, and gaster, the remaining hairs are suberect to decumbent, and present on the head, scape, dorsum of the mesosoma, petiole, and the legs, including the tibiae.

The mandibles are longitudinally striate, the dorsum of head has transverse rugulae, or striae, which curve anteriorly between the eyes and frontal carinae, and on the sides of head. The rugulae on the ventral surface of the head curve obliquely and extend anteriorly. The dorsum of the pronotum has transverse striae, which form concentric circles laterally, the mesonotum has transverse striae, the propodeum has transverse striae, which curve obliquely anteriorly and align with the striae present on the mesopleuron. The side of the petiole has a mixture of transverse (posteriorly) to obliquely vertical (anteriorly striae), the striae on the dorsum of the petiole are transverse, the postpetiole and the remainder of the gaster have fine, coriaceous sculpture, and are mostly smooth and glossy. The female and male are unknown.

Type Material
Holotype worker, 6 paratype workers Costa Rica, Punt., Las Cruces 4 kS San Vito, 19-vi-1998, R. Anderson # 18662.

Etymology
Named in honor of the collector, Bob Anderson, who has given us thousands of tropical ants.