Camponotus pellitus Mayr

Wild, A. L., 2007, A catalogue of the ants of Paraguay (Hymenoptera: Formicidae)., Zootaxa 1622, pp. 1-55 : 45-46

Camponotus pellitus Mayr 1862. REVISED STATUS.

Camponotus pellitus Mayr 1862:668. [holotype w examined, NHMW; Brazil]

Camponotus pellitus var. scintillans Forel 1901e: 72. NEW SYNONYMY. [w syntypes examined, MHNG; Paraguay (Jerrmann)]

Camponotus blandus Emery (nec F. Smith) 1903: 67 (part). Misidentification.

Camponotus (Myrmamblis) pellitus Mayr . Bruch 1914: 229.

Camponotus blandus pellitus Mayr . Santschi 1922b: 111.

Camponotus blandus st. scintillans Forel . Santschi 1922b: 111.

Camponotus (Myrmaphaenus) blandus subsp. scintillans Forel . Emery 1925: 154.

Camponotus (Myrmaphaenus) blandus var. pellitus Mayr . Kempf 1972: 44.

Camponotus (Myrmaphaenus) blandus scintillans Forel . Kempf 1972: 45.

The names associated with Camponotus blandus present one of the most difficult taxonomic problems in the Paraguayan fauna, and one that is particularly frustrating given the abundance of these ants in open habitats throughout the region. Multiple closely-related species certainly occur in Paraguay, but aside from Santschi’s C. crispulus (see separate discussion under that species), the taxonomic status of these forms is ambiguous and the arrangement in the present study is tenuous.

In eastern Paraguay, most collections are of dark-colored ants closely matching Mayr’s type of C. pellitus from Brazil and Forel’s types of C. scintillans from Paraguay. Workers from western Paraguay are almost universally bicolored with a red head and mesosoma and dark legs and gaster. The major workers of these chaco forms have finer suberect hairs on the sides of the head, spaced more densely, than do workers of C. pellitus , and the postero-lateral corners of the head of the largest workers are often more produced. Minor workers of the bicolored forms have smaller eyes than do minors of C. pellitus , and they have a slightly lower, less convex propodeum. Both forms co-occur in eastern Paraguay near the Paraguay River with little evidence of interbreeding. Forel’s types of C. rosariensis fall within the range of variation of these bicolored chacoan forms, so I adopt here a two-species scheme with C. rosariensis representing the bulk of the chacoan collections and C. pellitus representing most of the eastern collections.

The chacoan forms, while difficult to subdivide further on the basis of external worker morphology, show two distinct nest phenotypes in reproductively mature colonies. I have observed these nest forms within a few meters of each other. One form constructs large, conspicuous crater mounds while the other has cryptic nest entrances in the soil consisting of a single small hole with a slight scattering of excavated earth placed up to half a meter away, a pattern similar to the nests of C. pellitus . This sympatric difference in nesting behavior suggests the existence of cryptic species.

F. Smith’s holotype of C. blandus , a minor worker from Pará (BMNH, examined), is not a close match to any Paraguayan material. This ant has the smaller eyes and the lower propodeum more similar to C. rosariensis than to C. pellitus , but with denser pubescence on gastric tergites 3 and 4 (= abd. tergites 5 and 6) than in most specimens of C. rosariensis . The C. blandus type is also colored differently, with the posterior portion of the head quite dark, as in C. pellitus , the mesosoma lighter, as in C. rosariensis , and the first gastric tergite concolorous with the mesosoma and infuscated posteriorly. However, I have not examined any material occurring between the type locality in Pará and Paraguay, so I cannot dismiss the eventuality that the name C. blandus may apply one of these subtropical populations.