Adelomyrmex betoi

A. betoi occurs in wet forest habitats above 1000 m in the mountains of Oaxaca and Veracruz states, Mexico.

Identification
Adelomyrmex betoi has a highly distinctive habitus. The rugae on the face and dorsal mesosoma are beaded, unlike all other species in the genus. The postpetiole has a short, concave, smooth and shining posterior face that is closely appressed to the gastral dorsum and sharply separated from the sculptured dorsal face by a pronounced sharp transverse carina. The postpetiole shape may represent a transitional stage between the long, posteriorly pointed postpetiole of Adelomyrmex silvestrii and the more globular to trapezoidal postpetiole of all other species. The three collections reported by Fernández are unique in the genus in being essentially hairless, with no erect setae on the dorsal surfaces of the head, mesosoma, and gaster. All other species in the genus are abundantly setose. However, a fourth collection is tentatively identified as A. betoi, although the workers differ dramatically in pilosity. A series of six workers was collected in a Berlese sample by R. S. Anderson in 1992 (RSA92-029), within a few km of the same locality as the Peck paratype, south of Valle Nacional in Oaxaca. In all size, shape, and sculpture characters they are identical to the paratype I have in my collection (S. Peck B204). However, they are abundantly clothed in dorsal pilosity, expressing the condition typical for the genus. Further work is needed to determine whether this variation is intra or interspecific. (Longino 2012)

Key to Adelomyrmex of the New World mainland

Distribution
Adelomyrmex betoi is only known from the three collections reported in Fernández (2003) and a fourth potentially conspecific collection discussed below. The holotype is from evergreen wet forest around some springs 10km NNE of Córdoba. Although I do not have the precise georeference for this area, the elevation of the region is between 1000 and 1500 m. A second site near Córdoba is reported, also near 1000 m elevation. The third reported site was 15 miles south of Valle Nacional. Although reported with an elevation of 400 ft, this is almost certainly an error. Fifteen miles south on the main highway from Valle Nacional is between 1500–1600 m elevation. Thus A. betoi occurs in wet forest habitats above 1000 m in the mountains of Oaxaca and Veracruz states, Mexico. (Longino 2012)

Distribution based on Regional Taxon Lists
Neotropical Region: Mexico.

Castes
Known only from the worker caste.

Nomenclature

 *  betoi. Adelomyrmex betoi Fernández, 2003b: 13, fig. 72 (w.) MEXICO.

Worker
Holotype. HL 0.59 HW 0.49 SL 0.32 EL 0.025 WL 0.55 GL 0.72 TL 2.35 CI 83 SI 67.

Mandibles with 5 teeth. Anterior margin of clypeal plate concave. Eyes small, with 4 ommatidia. Hypostomal tooth inconspicuous. Mesosoma evenly curved, metanotal groove shallow. Propodeal teeth triangular, the point upward. Petiolar node thick. Postpetiole posteriorly with a strong transverse carinae. Head rugoreticulated, the rugulae long, longitudinal, the sculpturation mixed with dense punctuation. Promesonotum irregularly rugolose at center, rugoreticulated in the periphery. All carinae or rugulae beade-like. Petiole and postpetiole laterally with irregular rugulae. Mesosoma and gaster devoid of any pilosity. Head, mesosoma, petiole, postpetiole dark brown, appendages and gaster brown.

Type Material
Holotype worker: MÉXICO: Veracruz, Córdoba, Paraje Nuevo, Nacimiento, tropical evergreen forest, Ver. 176, 7.viii.1969, S. & J. Peck (Deposited in ). Paratypes: MÉXICO: 3 w, Veracruz, 4.4 mi N Huatusco, 4200’, 2.viii.1973, A. Newton. 13 w, MÉXICO: Oaxaca, 15 mi S Valle Nacional town, 400 feet, 21.V.1971, S. Peck leg. No. 204 (Deposited in, , , , , , , ).