Adelomyrmex longinoi

This species occurs in mature wet forest leaf litter. It is most abundant in the lowlands but can occur as high as 1100 m elevation (Parque Nacional Azul Meambar, Honduras). The northern limit appears to be just across the Motagua fault in southeastern Guatemala. It is widespread in wet forests of Honduras and Nicaragua. In Costa Rica it occurs on both lowland Atlantic and southern Pacific slopes, but only to 500 m elevation. When present it is always a low-density element of the fauna, occurring in 1–10% of miniWinkler samples, and usually as one or two individuals per sample. (Longino 2012)

Identification
In the northern part of its range A. longinoi is sympatric with the closely similar Adelomyrmex marginodus, and the two species may occur together in the same Winkler samples. The anterior and dorsal faces of the pronotum are less sharply differentiated in A. longinoi, and the posterior margin of the postpetiole lacks a pronounced transverse rim. DNA barcoding evidence supports the distinctness of the two species. Fernández (2003) commented on Chiapas specimens tentatively identified as A. longinoi; these are almost certainly A. marginodus. (Longino 2012)

Key to Adelomyrmex of the New World mainland

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

Nomenclature

 *  longinoi. Adelomyrmex longinoi Fernández, 2003b: 21 (w.q.) COSTA RICA.

Worker
Measurements. Holotype (Paratype). HL 0.49 (0.50) HW 0.40 (0.41) SL 0.26 (0.28) EL 0.025 (0.030) WL 0.42 (0.44) GL 0.56 (0.56) TL 1.72 (1.76) CI 83 (83) SI 64 (69).

Mandibles with 6 teeth, the three apical larger. Anterior margin of clypeal plate concave. Lateral clypeal teeth very reduced, smaller than median clypeal teeth. Eyes small, with 4 ommatidia. Hypostomal tooth small, inconspicuous. Promesonotum continuous, slightly convex and slightly higher than propodeum. Propodeal teeth triangular. Petiolar node narrow rounded above. Postpetiole with transverse carinae in their posterior face. Head rugoreticulated. Promesonotum irregularly rugose. Sides of pronotum, petiole and postpetiole rugoreticulated. Sides of mesosoma irregularly rugulose. Body red brown, appendages lighter.

Type Material
Longino (2012) - The holotype of A. longinoi is currently missing. Queries have not located it at BMNH, IAVH, ICN, INBIO, LACM, MIZA, MZSP, USNM. However, abundant material from the type locality is available in museums, and multiple specimens exist from the same miniWinkler sample.