Camponotus johnsoni

The types of C. johnsoni were collected in Baja california, Mexico, in a riparian area, under stones. Males were present in a nest in May.

Compare with Camponotus americanus, Camponotus laevigatus, Camponotus laevissimus.

The major of C. johnsoni is a medium to dark brown, shiny, relatively small (total length 8 mm) specimen. The mandibles are coarsely punctated, but the region between the punctures is smooth and shiny. The dorsum of the head is very finely sculptured and mostly glossy, but with scattered, coarse punctures, especially obvious on the clypeus, between the frontal carinae and the cheeks. The antennal scape extends less than the first funicular segment past the posterior lateral corner of the head. Erect and suberect setae are abundant on most surfaces, including the cheeks (only a few setae are present), but are absent on the scape, except at the apex. Most other surfaces have abundant, erect and suberect setae. Appressed pubescence is sparse, with a few scattered setae present on the head (0.1 mm in length), on the dorsum of the mesosoma (0.05 mm) and the dorsum of the gaster (0.1 mm). The setae are not dense enough that they touch adjacent setae on any of the surfaces. The middle and posterior tibiae are covered with appressed setae and with a few bristles along the distal half of the flexor surface.

The smaller majors of C. johnsoni are intermediate in size (6 - 7 mm total length) and are similar to the larger majors, except the antennal scape extends past the posterior lateral corner of the head by about the length of the first funicular segment.

Minor workers of C. johnsoni are similar to the major workers in terms of sculpture, pilosity and color. Most surfaces are smooth and nearly glossy, but scattered coarse punctures are present on the head, especially on the cheeks.

The female of C. johnsoni is unknown; the male is a small (total length < 7 mm) black specimen.

Comparisons
Camponotus johnsoni can be separated from two other shiny ants, Camponotus laevissimus (SW Canada, western US) and Camponotus laevigatus (California and Baja California) by color, it is reddish brown and the other two species are black.

The color of C. johnsoni is similar to that of Camponotus americanus. Camponotus johnsoni is easily separated from C. americanus by its much smaller size, about half that of C. americanus, which is primarily found in the eastern part of the United States and is unknown from California and Mexico.

Distribution based on Regional Taxon Lists
Neotropical Region: Mexico.

Nomenclature

 * . Camponotus (Camponotus) johnsoni Mackay, 2019: 233, figs. 190, 191, 232-237, pls 16-18 (s.w.m.) MEXICO (Baja California).

Major worker measurements (mm): HL 2.04 - 2.34, HW 2.16 - 2.36, SL 1.44 - 1.62, EL 0.36 - 0.41, CL 0.63 - 0.74, CW 0.94 - 1.01, WL 2.46 - 2.76, FFL 1.44 - 1.68, FFW 0.43 - 0.53. Indices: CI 101 - 106, SI 69 - 71, CLI 137 - 150, FFI 30 - 31.

Mandible with 6 teeth, basalmost tooth poorly developed; anterior border of clypeus convex, rounded, clypeal carina absent; sides of head nearly parallel, narrowing anteriorly, posterior border straight to slightly concave; eyes failing to reach sides of head by about ⅓ - ½ times minimum diameter; scape extends less than first funicular segment (largest major) to first segment (smaller major) past posterior lateral corner of head; mesosoma broadly rounded throughout, including region between faces of propodeum; propodeal spiracle elongated; petiole moderately thickened when viewed in profile.

Erect and suberect setae abundant across surface of clypeus, cheek with few, scattered, erect and suberect setae, malar area with few or no erect and suberect setae, side of head in vicinity of eye without erect and suberect setae, erect and suberect setae scattered between frontal carinae, on frons, across posterior margin of head, on ventral surface of head, on dorsum of mesosoma, of petiole and all surfaces of gaster, setae on tibiae mostly appressed, few, scattered bristles on distal half of flexor surface of tibiae; appressed setae sparse on dorsum of head, dorsum of mesosoma and dorsum of gaster; setae do not touch adjacent setae.

Most surfaces smooth and glossy, dorsum of head very finely coriaceous, with scattered punctures, punctures between frontal carinae abundant, mostly small, mesosoma finely coriaceous, dorsum of gaster finely, transversely striolate.

Head and gaster dark brown, mesosoma and legs medium brown.

Intermediate worker measurements (mm): HL 1.84 - 1.88, HW 1.86, SL 1.40 - 1.42, EL 0.35 - 0.39, CL 0.58 - 0.60, CW 0.84 - 0.85, WL 2.22 - 2.24, FFL 1.42 - 1.48, FFW 0.41. Indices: CI 99 - 101, SI 76, CLI 142 - 146, FFI 28 - 29.

Similar to major worker, differing in having relatively longer scapes.

Minor worker measurements (mm): HL 1.02 - 1.50, HW 0.92 - 1.44, SL 0.88 - 1.26, EL 0.25 - 0.35, CL 0.26 - 0.44, CW 0.48 - 0.70, WL 1.32 - 1.90, FFL 0.82 - 1.02, FFW 0.25 - 0.33. Indices: CI 90 - 96, SI 84 - 86, CLI 160 - 181, FFI 30 - 32.

Mandible with 5 teeth; anterior border of clypeus broadly convex, carina poorly developed; sides of head nearly parallel, posterior border broadly rounded; eye nearly reaches sides of head; scape extends ⅓ - ½ length past posterior lateral corner of head; mesosoma broadly rounded dorsally; propodeal spiracle elongate; petiole moderately thickened when viewed in profile.

Sculpture, pilosity and color as in major worker.

Male measurements (mm): HL 1.02 - 1.08, HW 0.96 - 1.06, SL 1.06 - 1.22, EL 0.39 - 0.40, CL 0.25, CW 0.51 - 0.53, WL 2.22 - 2.26, FFL 1.48 - 1.56, FFW 0.29 - 0.30. Indices: CI 94 - 98, SI 104 - 113, CLI 205 - 210, FFI 19.

Small black specimen, similar to other small males.