Camponotus aterrimus

Aibek & Yamane (2009) collected this species in eastern part (Domodaimag) of Mongolia from two colonies; in Numrug located close to inner Mongolia foraging workers were commonly found. It inhabits open sites at relatively low altitudes between 600 and 800 m. Nests were constructed in soil and the burrow was dug directly from the ground surface just as in cases observed for Camponotus japonicus in Japan. Our material contains a few specimens of this species from north-central pan (Bogdkhaan and Huslai). Yasumatsu and Brown (1957) correctly pointed out that Camponotus japonicus (including aterrimus) always nests under ground.

Identification
Camponotus aterrimus can be separated from Camponotus sachalinensis and Camponotus saxatilis by the following characteristics (Aibek & Yamane, 2009):
 * 1) in the smallest worker the dorsal outline of alitrunk in profile almost constantly arched throughout
 * 2) propodeum with standing hairs down to the midlength of its posterior face
 * 3) even in the larger workers the mandible basally without striae
 * 4) clypeus often produced anteriad as a short lobe

In the single syntype queen of C. aterrimus from Russia the clypeus is anteriorly produced as a short lobe as in the queen of C. japonicus; these two are distinguished from C. sachalinensis and C. saxatilis by this and the following additional characteristics:
 * gastral tergites with denser and longer pubescence
 * appressed hairs in length subequal to the distance between them or more
 * anterior pan of the head, mandible and legs reddish

In the male C. japonicus is separated from C. sachalinensis and C. saxutilis by the following characteristics:
 * 1) seen from back the upper margin of petiole almost straight, with dorsolateral comers round, but petiole posterodorsally weakly produced at the middle
 * 2) in both the queen and male the forewings almost wholly transparent, only slightly infuscated along the anterior margin

Distribution based on Regional Taxon Lists
Palaearctic Region: China, Kazakhstan, Mongolia, Russian Federation.

Nomenclature

 *  aterrimus. Camponotus pennsylvanicus var. aterrimus Emery, 1895k: 478 (footnote) (w.q.) RUSSIA.
 * Ruzsky, 1905b: 238 (m.); Karavaiev, 1912b: 594 (s.).
 * Combination in C. (Camponotus): Emery, 1925b: 73.
 * Subspecies of herculeanus: Ruzsky, 1915a: 419.
 * Subspecies of japonicus: Santschi, 1925f: 88; Wheeler, W.M. 1929f: 9; Arnol'di, 1967: 1827; Kupyanskaya, 1990: 170.
 * Senior synonym of manczshuricus: Arnol'di, 1967: 1827.
 * Junior synonym of japonicus: Kuznetsov-Ugamsky, 1929a: 17; Yasumatsu & Brown, 1951: 36; Radchenko, 1997a: 556.
 * Status as species: Ruzsky, 1926: 108; Aibek & Yamane, 2009: 99.

Taxonomic Notes
Aibek & Yamane (2009) - Kupyanskaya (1990, 1995) has treated this form as a subspecies of Camponotus japonicus. Pfeiffer el al. (2007) considered (but not clearly stated) aterrimus as a junior synonym of japonicus. We treat C. aterrimus as a distinct species since the gastral pubescence in the worker is distinctly shorter and sparser than in C. japonicus (see also Emery. 1895). In other respects, including nesting habits, these two are not separable. Since any of previous papers on Asian Camponotus did not mention the most important recognition characteristics of C. japonicus + C. aterrimus (1 and 2 mentioned above), previous records of C. aterrimus from Mongolia should be reexamined. The queen and male are not available for the Mongolian population of C. aterrimus.