Ctenopyga Ashmead
Creators: name: Brown, W. L.
Publisher: name: Zenodo
Year: 1975
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Formicidae
Ctenopyga

description: Ctenopyga
(provisionally restored to generic status)
= Ctenopyga Ashmead, 1906: 29 - 30, dealate [[queen]] and [[male]]. Type: Ctenopyga townsendi Ashmead = Acanthostichus texanus Forel, by original designation, monobasic.
<Acanthostichus: Forel, 1904: 168, dealate [[queen]]. ----- Brown, 1973: 179. = Acanthostichus subgenus Ctenopyga: Emery, 1911: 13. ----- M. R. Smith,
1947, Amer. Midl. Natur. 37: 526, pl. 1, fig. 4, 529, [[queen]]. ----- M. R. Smith, 1955: 49 - 50, synonymy and distribution summarized.
I considered this genus to be a straight synonym of Acanthostichus until a very late stage of the preparation of this part of the Reclassification — so late, in fact, that for very compelling reasons, publication can no longer be delayed while I make the studies of type specimens necessary to fully define Ctenopyga. Under the circumstances, it might seem better for me to have left things as they stand, with Ctenopyga, as considered by most workers, either a subgenus or a synonym of Acanthostichus. Such a solution, after all, would only recall the situation in Sphinctomyrmex, in which subdichthadiiform queens and winged queens are found in different species of the same genus. In Acanthostichus, however, we do not know of any intermediate kinds of queens such as we have in Sphinctomyrmex; the queens known for 2 of the 6 - 8 valid South American Acanthostichus species are both subdichthadiiform, while that of the single valid Ctenopyga species is large-eyed and winged. The geographical distribution of these forms may also be significant; Acanthostichus is South American, with no known representation west of the Andes, in northern Venezuela, or in Central America. Only 1 species, A. skwarrae, is known from outside continental South America, and this somewhat aberrant form, from Veracruz, is represented by a single (now headless) worker; it could well belong to Ctenopyga, and it must at least be considered as doubtfully belonging to Acanthostichus. For what the negative evidence may be worth, no winged or dealate female " Acanthostichus " have yet been reported from South or Central America, at light or otherwise.
Evidence from the males is also noteworthy. The Acanthostichus s. str. males so far reported, all from South America, have distinctive 12 - merous antennae with the funiculus gradually but distinctly broadened from base toward apex; the pedicel is short, and the following segment (funiculus II) is even shorter. The genitalia of these males (at least 3 species examined, none associated with workers or queens) varies among species, but all specimens have a distinctive aedeagus (figs. 140, 141) in which the valves are broad, each coarsely serrate on the convex ventral margin, with the apex differentiated as a last and largest, beaklike, downcurved point, separated from the serrations by a curved emargination. Such males have been taken on numerous occasions at light at widely separated points in South America, but they are unreported from Central or North America.
The 2 males originally described as Ctenopyga townsendi were collected at La Puerta, presumably in Chihuahua, by C. H. T. Townsend. They came on separate pins, and the dealate queen described with them, from the same locality, was on another pin. So far as I am aware, no males and queens of this species under any name have ever been taken in the nest, in copulo, or in any circumstances that would make it reasonably certain that they belonged to the same species. Apart from locality data, all we have to go on are Ashmead's original assumption that male and queen were conspecific and certain habitus indications that both sexes are " cerapachyine. " With these considerations in mind, I belatedly dissected the terminalia of a syntype male of C. townsendi, which M. R. Smith (1947, loc. cit. supra) has shown to be a junior synonym of C. texanus.
To begin with, the C. townsendi male has a furciform subgenital plate, but the 2 teeth are much broader and more triangular than in the South American Acanthostichus. The parameres and laciniae are also quite different, but these parts can differ considerably between species in Acanthostichus. In the valves of the aedeagus comes the big difference; the townsendi male type has slender aedeagal valves broadened into thick, angularly capitate apices; the stem-like basal parts are smooth, without any sign of serration along their concave ventral edges. The other fact about the C. townsendi male — a character that seems long to have been lost sight of — is that the antennae have 13 segments, with the funiculus not so distinctly incrassate as in most South American Acanthostichus. In genitalic and other characters, in fact, the C. townsendi type looks more like the numerous light-caught males attributed to Cerapachys augustae by M. R. Smith (1942) and others than like the South American Acanthostichus. Thus it seems to me that we should face up to the possibility that the assumed male of Ctenopyga texana (= townsendi) is instead the male of some Cerapachys species. If the assumed male does in fact prove to be the real male of C texana, then the differences between Acanthostichus and Ctenopyga are widened, and generic distinction is made surer than when it is based upon the queen alone.
Much depends on determining what kind of male and queen go with A. skwarrae, and what kind of worker goes with male and queen C. texanus. Smith (1955: 48 - 49) mentions an Arizona worker specimen that he did not feel confident in associating with texanus. This problem may be solved by other material already in collections, since samples from Sonoran North America have been accumulating rapidly in recent years, but if such samples exist, I have not seen them.
Meanwhile, taxonomic logic seems best served by considering Ctenopyga, with the sole known species texanus, to be a genus apart from Acanthostichus. The species skwarrae could well belong to Ctenopyga, but in the lack of hard evidence, it remains formally in Acanthostichus. Thus, Ctenopyga is left with the single species texanus (= townsendi), for which M. R. Smith (1955) is the appropriate summary reference. Ctenopyga seems to be centered in the Sonoran zone of Mexico, with extensions into southern Texas, New Mexico, Arizona, and eventually, perhaps, southern California. The best assumption is that, like Acanthostichus, it feeds on termites, but this remains to be checked.
description: Published as part of Brown, W. L., 1975, Contributions toward a reclassification of the Formicidae. V. Ponerinae, tribes Platythyreini, Cerapachyini, Cylindromyrmecini, Acanthostichini, and Aenictogitini., pp. 1-115 in Search: Agriculture; Cornell University Agricultural Experiment Station 15 on pages 42-43