Adelomyrmex marginodus

This species is known from lowland rainforest sites, from sea level to 400 m elevation. All records are from Winkler samples of sifted litter. It is typically rare, but at one Honduran site it occurred in 17% of miniWinkler samples. (Longino 2012)

Identification
Differing from the similar Adelomyrmex longinoi in (1) more sharply differentiated anterior and dorsal face of pronotum in profile; and (2) posterior margin of postpetiole with sharp projecting transverse rim. Character differences are subtle yet consistent across a broad zone of sympatry in Guatemala, Honduras, and Nicaragua. (Longino 2012)

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

Nomenclature

 *  marginodus. Adelomyrmex marginodus Longino, 2012: 20, figs. 3, 16, 21 (w.q.) MEXICO.

Description
HW 0.44–0.50 (n=5); mandible with differentiated masticatory and basal margins; masticatory margin with 5 teeth; basal margin sinuous with a distinct basal tooth and notch between tooth and condyle; dorsal surface of mandible with several coarse longitudinal striae and several large piligerous puncta; in full face view, lateral clypeal teeth small but still projecting from beneath clypeal shelf; lateral clypeal teeth located on anterior (ventral) margin of clypeus and separate from transverse carina that forms clypeal shelf; hypostomal tooth a minute triangular denticle; compound eye composed of 1–4 ommatidia; face coarsely reticulate rugose, with weak longitudinal orientation.

Short anterior face of pronotum meeting dorsal face at nearly right angle, separated by a low, simple transverse ruga; promesonotum evenly and very shallowly convex; metanotal groove weakly impressed; propodeal spines pronounced, triangular, acute at tip; space between propodeal spines a broad concavity without distinct dorsal and posterior faces, smooth and shiny with a moderately strong transverse ruga between propodeal spines, a few weaker rugulae above it; sculpture of dorsal promesonotum and side of mesosoma reticulate rugose like face; petiolar node relatively tall with differentiated anterior, dorsal, and posterior faces, rugose; postpetiolar node low and rounded, rugose laterally, smooth and shiny dorsally; in profile, postpetiolar node with a pronounced posteroventral rim; postpetiole in dorsal view about as long as wide, evenly rounded posteriorly; gastral dorsum smooth and shining.

Scape with abundant subdecumbent pubescence, and with two long suberect setae that are differentiated from the pubescence and project above it; clypeus and frontal carinae with long erect setae; posterior and posterolateral margins of head with long erect setae; mid and hind tibia with abundant long subdecumbent setae and 2–3 differentiated erect setae that are longer than width of tibia; in profile, dorsal surfaces of head, mesosoma, and gaster with relatively short, dense subdecumbent setae; FSH about 0.03, FSI 0.06.

Head and mesosoma red, gaster lighter yellow red.

Queen
Similar to worker except for queen-specific characters of large compound eyes, ocelli, and enlarged mesosoma with queen-typical sclerites; pronotum weakly reticulate rugose medially, coarsely reticulate rugose laterally; dorsal mesonotum smooth and shiny medially, grading into concentric rugulae peripherally; scutellum more coarsely reticulate rugose; katepisternum, anepisternum, and side of propodeum rugose, rugae somewhat more longitudinally oriented than on lateral pronotum.

Type Material
Holotype worker Honduras, Atlántida: 7 km SSW Tela, 15.72337 −87.45177 ±20 m, 190 m, 15 Jun 2010 (LLAMA Wa-C-08-2-43) [CAS, unique specimen identifier CASENT0627826]. Paratypes (workers): Honduras, Atlántida: 7 km SSW Tela, 15.72453 −87.45192 ±20 m, 190 m, 15 Jun 2010 (LLAMA Wa-C-08-2-17) [MCZC, CASENT0618409]; Honduras, Atlántida: 12km SW La Ceiba, 15.69130 −86.86076 ±20 m, 280 m, 19 Jun 2010 (LLAMA Wa-C-09-2-17) [BMNH, CASENT0627830], [EAPZ, CASENT0627831], [ECOSCE, CASENT0627832], [MZSP, CASENT0627828], [UCD, CASENT0627833], [USNM, CASENT0627829]; same data but 15.69116 −86.86075 ±20 m (LLAMA Wa-C-09-2-20) [ICN, CASENT0627834].

Etymology
Referring to the posterior rim of the postpetiole.

References based on Global Ant Biodiversity Informatics

 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Longino J. T. 2012. A review of the ant genus Adelomyrmex Emery 1897 (Hymenoptera, Formicidae) in Central America. Zootaxa 3456: 1-35
 * Longino J. T. L., and M. G. Branstetter. 2018. The truncated bell: an enigmatic but pervasive elevational diversity pattern in Middle American ants. Ecography 41: 1-12.
 * Longino J. et al. ADMAC project. Accessed on March 24th 2017 at https://sites.google.com/site/admacsite/