Myrmentoma

Cleft-lip Carpenter Ants

Diagnosis. Emery (1925) - "Worker and queen. - Medium species, generally robust; caste dimorphism pronounced. Head of majors and queens broad, neither truncated nor obtuse anteriorly, and with lateral margins arced, converging anteriorly somewhat; posterior head margin linear or slightly convex; head of minors stretched out, rounded posteriorly. Clypeus of majors without median carina, generally subcarinate in minors; with or without rounded anterior lobe; anterior margin usually medially notched or depressed; cheeks do not dominate the clypeus in majors and queens. Mandible with 5 or 6 teeth. Dorsum of mesosoma arched and continuous in majors, without margination, and with long propodeum; or more-or-less strongly impressed at the meso-metanotal suture, with dorsal peopoeal face usually marginate along sides and posterior margin. Petiolar scale more-or-less thick, but not nodiform. Male. - Body slightly long, head short. Antennae relatively short; antennomeres of flagellum somewhat longer than wide; pedicel longer and thicker than third antennomere; antennomeres 4 and 5 not much longer than apical antennomere.

Geographical distribution of the species.- Temperate and warm countries of the Holarctic Region, as far as Guatemala in America, and in the Old World, from Mediterranean Africa to the Himalayas; a doubtful record of one species from Taiwan.

Ethology. - The species of this group inhabit in small populations the bark of the trees, the dry branches and sometimes also the soil.''

(Translated and edited by B. E. Boudinot, 17 February 2017.)

Myrmentoma is currently a subgenus of Camponotus.

Species groups of Myrmentoma
Emery (1925) divided Myrmentoma into three species groups, which he diagnosed as follows:

"Group I: caryae

Diagnosis. - Mesosomal dorsum of worker continuous.

Group II: lateralis

Diagnosis. - Mesosomal dorsum of workers impressed anterior to propodeum. Cuticle shining.

Siefert (2019) stated "The subgenus Myrmentoma was characterized by Forel (1912) by nothing more than ‘Thorax echancré. Epinotum cubique.’ and among the species he collected under this subgenus were Camponotus lateralis and Camponotus kiesenwetteri. Camponotus lateralis was later assigned as type species of Myrmentoma (Wheeler 1913, Bolton 2003). It is obvious that the characters named by Forel cannot serve to delimit a subgenus because of morphological transitions to other members of the genus Camponotus. This dilemma is not easily resolved but Forel’s characterization provides an idea what we may operationally consider here as a Camponotus lateralis group. The Westpalaearctic species of the C. lateralis group are size dimorphic, rather small-sized in terms of the genus and are mainly found in warm or hot regions with Mediterranean climate." Seifert's definition of this group - Camponotus lateralis species group.

Group III: kiesenwetteri

Diagnosis. - Mesosomal dorsum more-or-less impressed, propodeum marginate. Cuticle matte."

Radchenko (1997) also reviewed species in this subgenus, and their placement in various species groups and complexes.

Nomenclature

 *  MYRMENTOMA [subgenus of Camponotus]
 * Myrmentoma Forel, 1912i: 92 [as subgenus of Camponotus]. Type-species: Formica lateralis, by subsequent designation of Wheeler, W.M. 1913a: 80.
 * Myrmentoma junior synonym of Orthonotomyrmex: Forel, 1913b: 350 (in text); Forel, 1914a: 264; Wheeler, W.M. 1922a: 970.
 * Myrmentoma subgenus of Camponotus: Emery, 1920b: 257; Wheeler, W.M. 1922a: 707; Emery, 1925a: 62; Emery, 1925b: 116.