Can I get some help? New world narrows to 4 Groups
I can not fully parse the diagnostic differences. Thanks.
Subfamily: Formicinae
Tribe: Camponotini
Genus: Camponotus
Tanaemyrmex is currently a subgenus of Camponotus
Slim Carpenter Ants
Diagnosis: Emery (1925): - "Workers. - Caste polymorphism generally very pronounced in head form and size; polymorphism gradual through extreme forms. Head of majors usually much wider posteriorly than anteriorly, truncated or notched on posteriorly. Head of minors elongated and of very different forms:
(Alpha) sides substantially parallel and posterior margin usually rounded; vertex not depressed.
(Beta) sides converging posteriorly from mouth; vertex evidently depressed and eyes more-or-less distant from posterior margin.
(Gamma) characters in this form become more and more pronounced: posterior half of head, from eyes, cone-shaped and occipital border disappears, reduced to articular border; sometimes, posterior extremity of head extends as neck and more-or-less marked, especially when posterior half of head is not conical but ogival (missile-shaped) (e.g., C. hildebrandtii, Forel, cervicalis, Roger, etc.).
There are, moreover, intermediaries between these forms of minor worker heads. Species in which minors have head forms Beta and Gamma have medias with heads which are more-or-less Alpha-form; head of minors with form Gamma and small medias or majors have head form Beta.
Species groups
Emery (1925) divided Tanaemyrmex into 12 species groups––four from the New World, and eight from the Old World––plus a number of "anonymous" (unnamed) groups of uncertain affinity. Below are his diagnoses of these groups, all based on workers:
SPECIES GROUPS OF AMERICA
Group I: chilensis-punctulatus
Diagnosis. - Head of minors of form Alpha; species more-or-less stocky, especially majors. Color generally black or dark, rarely pale; gasters of some species covered with more-or-less dense pubescence. Transition more or less marked to Camponotus sensu stricto and Myrmaphaenus.
Group II: picipes-fumidus
Diagnosis. - Head of minors of form Alpha. Species not stocky. Color variable, rarely uniform yellow. In some species tibial setae more-or-less detached erect (transitioning to Myrmothrix).
Group III: Iandolti-agra
Diagnosis. - Head of minors of form Beta or Gamma; species medium-sized to very large; elongate to very elongate, especially minors; legs not hairy. Includes American species of subgenus Dinomyrmex sensu Forel.
Group IV: cacicus
Diagnosis. - As for previous group, but with numerous standing setae.
---
Clypeus generally carinate medially; anterior margin with more-or-less prominant lobe, lobe square or rounded, rarely notched or acute medially; lobe often rounded in minors, and becomes increasingly rectangular in larger workers; medioclypeus (middle portion of clypeus between anterior tentorial pits) not prominent in majors, so that in workers of all sizes clypeus as a whole (excluding anterior lobe and lateral clypeal parts) is trapezoidal. Frontal carinae more-or-less sinuate; antennal insertions usually not far from posterior clypeal margin. Mandibles with simple teeth (usually 6–7), apical tooth longer than others, but not excessively. Mesosomal dorsum never marginate, arched in profile, propodeum rarely hollowed out posteriorly or with saddle-shape. Petiole surmounted by more-or-less high scale, rarely nodiform, rarely with unpaired spine (C. hastifer, Emery, hoplites, Emery). Sculpture and investiture variable; in some American species, gaster covered with fur-like pubescence (e.g., C. chilensis, Spinola). Setae of scapes and tibiae in American species never erect, long and abundant, except in C. cacicus, Emery. Queens. - Head form similar to majors, but not of largest workers in a colony. Males. - Head more-or-less elongated. Antennae long: scape exceeding posterior head margin by at least half its length; pedicel and flagellum composed of more-or-less elongate antennomeres, pedicel nor or only slightly longer than antennomere 3 and not at all pyriform (pear-shaped); rarely antennomeres of flagellum very short and pedicel somewhat pyriform (e.g., C. friedae, Forel, acvapimensis, Mayr, punctulatus, Mayr).