Adelomyrmex paratristani

A common species in the ground litter of some cloud forests within its range.

Identification
Longino (2012) - With the characters of Adelomyrmex tristani; differing in the relatively longer, sparser, more erect pilosity on the face, mesosoma, and gaster; FSH usually > 0.06 mm, FSI > 0.1 (in A. tristani, FSH usually < 0.06 mm, FSI < 0.1); in sympatry, A. paratristani is larger than A. tristani.

Variation In the northern and southern limits of the range, the posterior margin of the worker postpetiole has 4–5 transverse rugae. The lowermost ruga is the largest, but not so much so that it forms a projecting step-like profile. In the center of the range, from central Honduras to southern Chiapas, the uppermost rugae on the postpetiolar node are reduced, resulting in a smaller, smoother postpetiole. The lowermost ruga on the posterior margin remains large, resulting in a step-like profile of the posterior face of the postpetiole. There is no evidence of sympatry of forms; instead they occur as allopatric populations on mountain tops. However, the transition can sharp and somewhat interdigitated. For example, in Honduras, Cerro Comayagua has the peripheral form, and Cerro Azul Meambar, 50 km to the northwest, has the central form.

Some collections of A. paratristani are difficult to differentiate from the lower elevation Adelomyrmex myops.

Distribution
southern Mexico to central Nicaragua

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

Habitat
This species occurs in montane wet forest, second growth and mature, from 1100–2500 m elevation. Forests can be diverse mesophyll cloud forest and various mixes of pine, oak, and Liquidambar forest.

Biology
Longino (2012) - Specimens are most often collected in Winkler or Berlese samples of sifted litter. Dealate queens occasionally occur in these samples. They can be dominant ants in cloud forest litter, and can occur in nearly 100% of miniWinkler samples. Workers also occasionally recruit to baits, and workers have been taken in beating samples of low vegetation.

A few nest collections are known. At Parque Nacional La Muralla, Honduras, a nest was found in a rotting Cecropia branch on the ground (in the sclerynchyma cylinders that resist decomposition); only workers and brood were found. Other nests have been found in larger pieces of rotting wood, usually just with workers and brood. In a cloud forest near Somoto in northern Nicaragua, a single small nest chamber was found in rotting wood. It contained 11 workers, one small larva, what appeared to be numerous eggs of the Adelomyrmex, and one large sphere that looked like a centipede egg. At this site workers were also found beneath dry epiphytes on a recent treefall. At the peak of Cerro Saslaya in east central Nicaragua, a moss-covered elfin forest, workers and brood were found in a small nest in the dense duff layer on the ground. Near Coapilla, Chiapas, Mexico, D. J. Cox observed either a mixed nest or two closely approximate nests in a dead hardwood gall on the ground, one of A. paratristani and one of Adelomyrmex robustus. At the time of collection he observed workers entering the gall. On later dissection, he observed a single entrance and three chambers. One chamber contained only larvae, one only pupae, and one mixed brood and workers. After dissection he realized there were two species of workers: A. paratristani and A. robustus. Among the A. paratristani were three dealate queens.

Nomenclature

 *  paratristani. Adelomyrmex paratristani Longino, 2012: 26, figs. 8, 10, 11, 19, 21 (w.q.) HONDURAS.

Worker
HW 0.54–0.71 (n=8); mandible with differentiated masticatory and basal margins; masticatory margin with 5–6 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 project 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 present as a minute denticle; compound eye composed of 6–16 ommatidia; face with longitudinally oriented rugae, linear to vermiculate.

Short anterior face of pronotum meeting dorsal face at obtuse angle, separated by a low, simple to somewhat crenulated transverse ruga; promesonotum evenly and shallowly convex; metanotal groove impressed; propodeal spines short, triangular, acute at tip; space between propodeal spines a broad concavity without distinct dorsal and posterior faces, smooth and shiny with 2–5 transverse rugae; rugae of dorsal promesonotum and side of mesosoma longitudinally oriented, linear to vermiculate; petiolar and postpetiolar nodes rounded, with coarse rugae; postpetiole in dorsal view about as long as wide, evenly rounded posteriorly; gastral dorsum smooth and shining.

Scape with abundant subdecumbent pubescence; 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 3–4 differentiated erect setae that are longer than width of tibia; in profile, dorsal surfaces of head, mesosoma, and gaster with relatively sparse, long, erect setae; FSH 0.06–0.11 mm, FSI 0.11–0.15 (n=8).

Color dark brown to black.

Queen
Similar to worker except for queen-specific characters of large compound eyes, ocelli, and enlarged mesosoma with queen-typical sclerites; pronotum smooth medially, laterally with coarse parallel rugae; mesonotum largely with longitudinal parallel rugae, with an anteromedian triangular patch that is smooth and shining; scutellum with longitudinal parallel rugae; katepisternum smooth and shining on anteroventral 2/3, with longitudinal parallel rugae along posterior and dorsal margins; anepisternum and side of propodeum with longitudinal parallel rugae.

Type Material
Holotype worker. Honduras, Olancho: PN La Muralla, 15.09798 −86.72081 ±15 m, 1850 m, 3 May 2010 (J. Longino#6956) [CAS, unique specimen identifier CASENT0615554]. Paratypes (workers): same data as holotype [BMNH, CASENT0627878], [INBIO, CASENT0627879], [MCZC, CASENT0627875], [MZSP, CASENT0627876], [UNAM, CASENT0627880], [USNM, CASENT0627877], [UVGC, CASENT0627881]; PN La Muralla, 15.09852 −86.72227 ±30 m, 1810 m, 3 May 2010 (J. Longino#6958) [EAPZ, CASENT0615557], [LACM, CASENT0627882]; PN La Muralla, 15.09721 −86.73840 ±100 m, 1480 m, 4 May 2010 (J. Longino#6997-s) [ICN, CASENT0615607]; PN La Muralla, 15.09814 −86.74039 ±20 m, 1530 m, 2 May 2010 (LLAMA Wa-C-01-1-02) [UCD, CASENT0615493]; PN La Muralla, 15.09934 −86.74069 ±20 m, 1530 m, 2 May 2010 (LLAMA Wa-C-01-1-29) [ECOSCE, CASENT0615007].

Etymology
Referring to its close similarity to Adelomyrmex tristani.

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