Mycetophylax andersoni

Two specimens were collected in montane hardwood leaf litter at 1100-1200 m elevation and in wet montane forest litter.

Identification
Mackay and Serna (2010) - The worker is a small (total length about 2.5 mm, n =2) reddish-brown ant. The mandibles have six teeth, the frontal carinae do not reach the dorsad occular suture, the frontovertexal corners are barely extended into auricle-like structures; the pronotum has three angulate processes or teeth, including the medial process and two lateral processes, together with a pair of posterior swellings, and the mesonotum has a pair of conical processes; the propodeum has a pair of anterior, blunt processes and two well-developed angulate posterior processes; and the posterior 1/3 of the petiole is raised into a blunt process that appears bidentate when seen obliquely from above; the postpetiole has two parallel raised regions on the dorsal surface; and the gaster lacks longitudinal raised areas. The posterior femur has a distinctive ventral angulate process, followed distally by a poorly defined carina.

This species would key to Mycetophylax olitor in Kempf (1964), found in Brazil and Argentina. Mycetophylax andersoni is somewhat larger (HL of M. olitor 0.64, HW 0.56 from Kempf, 1964), has fewer mandibular teeth (7-8 in M. olitor), the midpronotal tubercle is approximately the same size as the lateral tubercles (midpronotal tubercle much smaller than lateral tubercles in M. olitor), and the propodeal spines are well developed (poorly developed in M. olitor). The mandibular teeth are worn and partially hidden by the clypeus in the holotype and badly worn in the mandible of the other specimen, but this species appears to be the only one of the strigatus species complex with six mandibular teeth (and as the members of the rimosus species complex all have five mandibular, it is apparently the only species in Cyphomyrmex with six teeth).

Distribution based on Regional Taxon Lists
Neotropical Region: Costa Rica, Guatemala, Honduras, Nicaragua.

Nomenclature

 *  andersoni. Cyphomyrmex andersoni Mackay, W.P. & Serna, 2010: 45, figs. 1-6 (w.) COSTA RICA.
 * Combination in Mycetophylax: Sosa-Calvo et al., 2017: 9.

Worker
HL 0.76-0.78, HW 0.64-D.66, 5L 0.58-D.60, EL 0.13-0.14, EW 0.08-0.10 WL 0.90-D.93. Indices: CI 84-85, 5I 74-79, OJ 65-73. Mandible with 6 teeth; anteclypeus broadly rounded; paraclypeal teeth (anterior teeth-like processes on the clypeus) spiniform, moderately developed; frontal lobes and frontal carinae relatively narrow, extending to frontovertexal corner (posterolateral angle between frons and vertex), forming carina that fuses with posterolateral margin of antennal scrobe, preocular carina continues posteriorly to form mesial margin of antennal scrobe; eyes relatively small, extending past sides of head; scape relatively short, barely reaches frontovertexal corner; pronotum with medial protuberance, 2 lateral, conical tubercles and 2 posterolateral lobate processes, anteroinfra angle of lateropronotum developed; 2 angulate conical tubercles on mesonotum (height approximately 0.05 mm); anterior margin of dorsopropodeum with 2 broad processes (height 0.03 mm), dorsopropodeum relatively short (0.08 mm from notopropodeal groove to highest point of anterior tubercles) posteropropodeum longer (0.25 mm, measured from anterior tubercles to metapleural lobe), propodeal spines small (length 0.04 mm) and rounded; petiole enlarged posteriorly, forming dorsal tubercles as seen in lateral view (length 0.1 mm, height 0.07 mm) that appears to have two lateral tiny bumps; postpetiole with longitudinal medial depression flanked by two longitudinal ridges; all femora swollen, fore femur with poorly developed longitudinal carina along posteroventral margin, middle femur similar, but carina poorly developed, posterior femur with well-developed longitudinal carina forming distinct angle distad about one third length from body.

Erect hairs absent, except on mandible; hairs on scape and head appressed, hairs on ventral surface of head and anterior margin of procoxa subdecumbent, hairs on mesosoma, petiole, postpetiole, legs and gaster appressed.

Type Material
Holotype worker, Costa Rica, Alajuela, 27 k Nand 8 k W west of San Ramon, 29-vi-6-vii-1999, R. Anderson # 19901, 99-1096, 10°13'30"N; 34°35'30"W.

Etymology
This new species is named in honor of Robert Anderson, who collected these specimens as well as thousands of other interesting specimens.