Camponotus nigriceps

Very large, widespread species that is common in the Darling Range. Nests in the Darling Range are often found in compacted laterite clay around the boles of trees, but are also made directly into soil. Their distribution likely includes all Australian states, although McArthur and Adams (1996) did not record it for the NT. (Heterick 2009)

Identification
A member of the Camponotus nigriceps species group. McArthur and Adams (1996) - In populations of C. nigriceps the gaster colour varies from black through browns to yellowish brown and the mesosoma varies from red-browns to yellow. The number of long setae on the propodeum varies from 20 to 100 (Fig. 27a-d). Populations resembling C. nigriceps perthiana have black gaster and reddish mesosoma with about 40-100 long setae on propodeum. Other populations possess similar pilosity but because of their lighter colour do not fit Forel's description of perthiana.

Because some populations of C. nigriceps resemble Camponotus loweryi and Camponotus eastwoodi in colour and pilosity, identification in these cases is only possible by examining minor workers thus: (i) erect setae on gula cover> 50% gula area in C. nigriceps; < 50% in C. eastwoodi; gula setae absent in all castes of C. loweryi and (ii) head sides of smallest minors in dorsal view taper to the rear in C. eastwoodi; C. loweryi and C. nignceps parallel, and rounded in larger minor and medium workers.

Heterick (2009) - The distribution of erect and sub-erect setae on the propodeum distinguishes C. nigriceps from the similar Camponotus dryandrae; setae being continuous along the propodeal dorsum in C. nigriceps, and concentrated near the propodeal angle in C. dryandrae.

Camponotus clarior strongly resembles C. nigriceps, but the former have workers with a pale coloured head, concolorous with the mesosoma and node.

Distribution
The known distribution covers most of Australia excluding the Northern Territory and north Western Australia. It extends into north Queensland but the paucity of specimens available for examination points to the need for more collection and study.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  nigriceps. Formica nigriceps Smith, F. 1858b: 38 (w.) AUSTRALIA. Mayr, 1876: 63 (m.); Forel, 1879a: 75 (q.m.); Wheeler, G.C. & Wheeler, J. 1974a: 61 (l.). Combination in Camponotus: Roger, 1863b: 4; in C. (Myrmoturba): Forel, 1913g: 191; in C. (Tanaemyrmex): Emery, 1925b: 103. Subspecies of consobrinus: Wheeler, W.M. 1933b: 23. Revived status as species: Clark, 1934c: 71. Senior synonym of perthianus: McArthur & Adams, 1996: 35.
 * perthianus. Camponotus (Tanaemyrmex) consobrinus var. perthianus Wheeler, W.M. 1933b: 23 (s.w.) AUSTRALIA. [First available use of Camponotus (Myrmoturba) nigriceps r. dimidiatus var. perthiana Forel, 1915b: 97; unavailable name (Taylor, 1986: 34).] Subspecies of consobrinus: Clark, 1934c: 71. Junior synonym of nigriceps: McArthur & Adams, 1996: 35.

Worker
Length 5.5 lines (=11 mm), pale ferruginous with the head black, the face anteriorly and the mandibles ferruginous. The clypeus slightly produced and widely emarginate, or rather notched in front, its extreme anterior margin black; the antennae ferruginous. Thorax rounded in front, and gradually narrowed and compressed towards the metathorax;the scale ovate, its margin rounded; the legs elongate. Abdomen ovate; the insect thinly sprinkled with erect ferruginous hairs.

McArthur and Adams (1996) - Colour: head black or dark brown sometimes with lighter patches, mandibles and anterior clypeus usually darker sometimes lighter, mesosoma and node honey colour or light brown sometimes reddish, coxa and femur lighter, tibia and tarsi reddish brown, gaster black to light brown, sometimes posterior is slightly darker than the anterior. Most of the head never lighter than most of gaster. Pilosity: to 0.3 mm long plentiful on gula, sometimes sparse on sides of head of major workers but always plentiful in minor workers to 0.4 mm plentiful on pronotum and mesonotum and >20 on propodeum (Fig. 27a-d), plentiful on gaster pointing backwards. Short setae on scapes raised 10-50°, short setae on midtibiae 20-40°. Pubescence: a coat of curved raised setae about 0.1 mm long, spaced < length, visible on the dorsum of mesosoma, sparse and more adpressed on head. Integument finely reticulate, head and gaster glossy. Node summit viewed from rear: convex or flat sometimes sharply convex in major workers (Fig. l2c), flat or weakly convex in other workers. Metanotum usually distinct in major workers.

HW = 1.60-4.30 mm; HL = 2.25-4.40 mm; n = 145. TL = 2·70-3.80 mm; n = 21. TL = 2.47 + 1.92 log HW (n =21, r = 0·95, s.e.(y), = 0.10, s.e.(x), = 0.06). PD:D = 1.5 in major workers increasing to 3.0 in minor workers.

Type Material
C. nigriceps:, I worker labelled 'Holotype' from Entomology Club Australia (11.620 Series 11.485). HW = 2.0 mm, HL= 3.2 mm, HT = 2.1 mm, TL = 3.1 mm.



Etymology
McArthur and Adams (1996) - Nigra (Latin: black), cephal (Greek: head). Smith described a specimen possessing a distinctive black head.