Myrmaphaenus

Myrmaphaenus sensu lato or sensu Emery

Shining Carpenter Ants

[Note: this common name refers particularly to the typical group of Myrmaphaenus, that of leydigi (see below).]

Diagnosis. Emery (1925). - "Worker, soldier, and queen. - Small and medium-sized species; caste dimorphism very pronounced; in many species there are but few intermediate forms (sometimes not at all) between majors and minors. Head of majors (or soldiers) and queens longer than wide; lateral head margins parallel or somewhat converging anteriorly, slightly curved or straight; when lateral margins straight, head very elongated and more-or-less obtusely truncate anteriorly (Paracolobopsis [see below]); posterior head margin generally straight or slightly convex in minors, straight or concave in margins, and rarely very convex. Clypeus undergoing similar intraspecific allometric change as in Myrmamblys; clypeus always distinctly carinate [Emery's emphasis], at least in part, even among the largest specimens, and in these, clypeus less produced anteriorly than the cheeks which exceed it considerably. Frontal carinae sinuate, divergent posteriorly; antennal insertions situated well anterior to midlength of frontal carinae. Mesosomal dorsum arched, continuous. Petiole squamiform, usually lenticular or flat posteriorly. Cuticle, at least that of head, matte; sometimes mandibles and contour of mouth more-or-less shining among majors (soldiers). Male.- (C. hermanni, Emery) Resembling those of Colobopsis.

Geographical distribution of species. - Southern United States to all of South America except the far south and Chile.

Notes: (1) I gathered in this subgenus part of the Myrmaphaenus of my 1920 revision along with Neomyrmamblys of Wheeler (Myrmamblys, Emery 1920), Paracolobopsis (Emery 1920) and some other species, having found, after much study, that the subgenera in question were not based on characteristics sufficiently important to justify their distinction as such. I designated groups within Myrmaphaenus for these erstwhile subgenera [see below]. (2) This group represents the American counterpart of Myrmamblys in the eastern hemisphere. (3) C. caperi, Forel, from Jamaica, which Forel classified in his subgenus Myrmothrix and Wheeler in his Myrmobrachys, has the head and clypeal structure of Myrmaphaenus; however, this species differs from the majority of the species in this group by its small eyes which are distant from the posterior head margin, even among small workers, as well by its long mesosoma with a more-or-less marginate pronotum and compressed and agnular propodeum with the posterior face slightly concave posteriorly, forming a saddle-like profile, reminiscent of certain Myrmamblys of the group reticulatus."

(Translated and edited by B. E. Boudinot, 19 February 2017.)

Myrmaphaenus is currently a subgenus of Camponotus.

Species groups of Myrmosphincta
Emery (1925) divided Myrmosphincta into five species groups, which he defined as follows:

"Group I: leydigi (type of subgenus)

Diagnosis. - Relatively large, almost entirely matte with microscopic sculpture giving distinct silky reflection; setae coarse, distributed across body.

Group II: blandus

Diagnosis. - Body completely covered with silky pubescence (except a few varieties). Size difference between majors and minors very considerable.

Group III: salvini (Paracolobopsis, Emery).

Diagnosis. - Head of soldiers more-or-less cylindrical (resembling Colobopsis). Head of workers with straight posterior margin and posterolateral angles pronounced; a narrowly rounded (blunt) ridge passes through posterolateral angles of head to eye (also present in some species of Myrmobrachys).

Group IV: novogranadensis (Neomyrmamblys, Wheeler).

Diagnosis. - Negative and highly variable.

Group V: capperi

Diagnosis. Worker. - Head oval, eyes small, distant from posterior head margin, even in minors. Propodeum compressed; dorsal face forming angle with posterior face in profile view."

Nomenclature

 *  MYRMAPHAENUS [subgenus of Camponotus]
 * Myrmaphaenus Emery, 1920b: 237 [as subgenus of Camponotus]. Type-species: Camponotus leydigi, by original designation.
 * Myrmaphaenus senior synonym of Neomyrmamblys, Paracolobopsis: Emery, 1925b: 152.
 * NEOMYRMAMBLYS [junior synonym of Myrmaphaenus]
 * Neomyrmamblys Wheeler, W.M. 1921a: 19 [as subgenus of Camponotus]. Type-species: Camponotus fastigatus, by subsequent designation of Santschi, 1921f: 311.
 * Neomyrmamblys junior synonym of Myrmaphaenus: Emery, 1925b: 152.
 * PARACOLOBOPSIS [junior synonym of Myrmaphaenus]
 * Paracolobopsis Emery, 1920b: 249 [as subgenus of Camponotus]. Type-species: Camponotus salvini, by original designation.
 * Paracolobopsis junior synonym of Myrmaphaenus: Emery, 1925b: 152.