Aphaenogaster longiceps

This is one of the most commonly encountered species of Aphaenogaster in Australia. It occurs in a wide range of habitats from swampy coastal scrub, wet sclerophyll and rainforests through to dry sclerophyll and Callitris woodlands. Nests in sandy soil are often highly visible with large, funnel-shaped entrances while nests in firmer soils are less obvious with low, scattered soil around entrances. Nests are also found under rocks or other objects on the ground. Activity around nests is generally restricted to a few workers excavating soil or defending the nest entrance. Foraging activity is primarily nocturnal and seems to be limited with workers foraging singly and primarily near the nest. This species has an extensive literature, including the following: Banks (1916) (association with mites), Crawley (1922a: 122) (biology), Barrett (1927) (habits, as A. longipes (sic)), Clark (1929: 121) (distribution), Clark (1934: 58) (distribution), Smith and Atherton (1944: 4) (biology, economic importance), Sloane and Sloane (1964) (nesting biology), Berg (1975) (seed dispersal), Imai, Crozier and Taylor (1977) (karyotype), Greenslade and Thompson (1981) (biology), Humphreys (1981) (relation to soils), Humphreys and Mitchell (1983) (relation to soils), Cowan et al. (1985) (relation to soils), Andersen (1988a) (relation to fire), Anderson (1988b) (relation to plants), Hughes and Westoby (1992a) (seed dispersal), Hughes and Westoby (1992b) (seed dispersal), Nicholls and McKenzie (1994) (distribution pattern) and York (1994) (relation to fire).

Identification
Hairs on underside of head randomly distributed and not forming a distinct psammophore; posterior margin of head broadly arched in full face view; shorter erect hairs on mesosomal dorsum (especially those on mesonotum) with blunt tips; propodeal spines long, the dorsal surfaces of propodeum and propodeal spines connected through a gentle concavity (so that the base of each spine is at approximately the same level as the dorsal surface of the propodeum). The long scapes and blunt mesonotal hairs will separate this species from near relatives.

Identification Keys including this Taxon
Key to Australian Aphaenogaster Species

Distribution based on Regional Taxon Lists
Australasian Region: Australia. Oriental Region: India, Nicobar Island. Palaearctic Region: China.

Nomenclature

 *  longiceps. Myrmica longiceps Smith, F. 1858b: 128 (w.) AUSTRALIA. Mayr, 1876: 98 (q.m.); Wheeler, G.C. & Wheeler, J. 1972b: 238 (l.); Imai, Crozier & Taylor, 1977: 348 (k.). Combination in Aphaenogaster: Mayr, 1876: 98; in Stenamma (Ischnomyrmex): Forel, 1899a: 118; in Aphaenogaster (Deromyrma): Forel, 1913g: 187; in Aphaenogaster (Nystalomyrma): Wheeler, W.M. 1916j: 216. Type-material redescribed: Crawley, 1922c: 19. Senior synonym of ruginota: Wheeler, W.M. 1916j: 217; of flava: Shattuck, 2008a: 33.
 * ruginota. Stenamma (Ischnomyrmex) longiceps r. ruginota Forel, 1902h: 440 (w.q.) AUSTRALIA. Emery, 1914b: 181 (m.). Combination in Aphaenogaster: Emery, 1914b: 181; in Aphaenogaster (Deromyrma): Forel, 1915b: 75. Raised to species: Forel, 1915b: 75. Junior synonym of longiceps: Wheeler, W.M. 1916j: 217.
 * flava. Aphaenogaster (Nystalomyrma) longiceps var. flava Emery, 1921f: 61 (m.) AUSTRALIA. Junior synonym of longiceps: Shattuck, 2008a: 33.

Description
Posterior margin of head broadly arched in full face view, the arch beginning at the occipital collar and with at most a weak angle separating the posterior and lateral margins of the head (often posterior and lateral margins forming a continuous surface). Hairs on venter of head randomly distributed and not forming a distinct psammophore. Mandibular sculpture composed of regularly sized striations. Shorter erect hairs on mesosomal dorsum (especially those on mesonotum) with blunt tips. Propodeal spines intermediate in length. Dorsal surfaces of propodeum and propodeal spines connected through a gentle concavity (so that the base of each spine is at approximately the same level as the dorsal surface of the propodeum). Petiolar node (in dorsal view) approximately square.

Measurements
Worker (n = 10, units = mm). CI 78-89; EI 19-24; EL 0.18-0.25; HL 0.99-1.43; HW 0.82-1.25; ML 1.50-2.07; MTL 1.04-1.41; SI 130-161; SL 1.3 1-1 .71.


 * CI: Cephalic index: HW/HL x 100.
 * EI: Eye index: EL/HW x 100.
 * EL: Maximum eye length with eye in full face view.
 * HL: Maximum head length in full face (dorsal) view, measured from the anterior-most point of the clypeal margin to the posterior-most point of the head proper (excluding the occipital collar).
 * HW: Maximum head width in full face (dorsal) view excluding the eyes.
 * ML: Mesosomal length measured from the anterior surface of the pronotum proper (excluding the collar) to the posterior extension of the propodeal lobes.
 * MTL: Maximum length of mid tibia, excluding the proximal part of the articulation which is received into the distal end of the femur.
 * SI: Scape index: SL/HW x 100.
 * SL: Length of the scape (first antennal segment) excluding the basal neck and condyle.

Taxonomy
Emery's (1921) A. flava is here treated as a junior synonym of A. longiceps. A. flava was established by indication based on a male from Queensland and figured in Emery (1914). Emery (1914) presented two figures, one identified as longiceps from Queensland and the other as longiceps ruginota from Sydney. Emery (1921) based flava on the figure of longiceps. Wheeler (1916) (before Emery established flava) stated that the differences between these males were "insignificant" and considered them to belong to the same taxon, longiceps (he considered ruginota to be a synonym of longiceps, a treatment supported during this study); he also mentions that the male of pythia is quite different. Unfortunately Emery (1921) gave no information on why he considered flava to be a distinct taxon.

In fact the males of longiceps and pythia are very similar, differing mainly in colour and size (being larger and darker in longiceps). The male of barbara, the only other species of Aphaenogaster known from Queensland, differs from both longiceps and pythia in lacking a metanotal groove and in having the occipital collar rounded. The males of both longiceps and pythia have distinct, angular metanotal grooves and the occipital collars are angular. What Wheeler (1916) considered to be the male of pythia may well have actually been the male barbara.

Emery's (1914) illustration of longiceps gives little hint as to whether this male belongs to longiceps or pythia, although barbara can be safely eliminated. The shape of the head does differ slightly between longiceps and pythia, and Emery's figure resembles longiceps more closely than pythia. Based on this flava is here treated as a synonym of longiceps rather than pythia.

It should be noted that the name flava was overlooked for 74 years, until Bolton (1995) drew attention to it in his world catalogue. The name's obscurity was due to the cryptic way in which it was established. The name was based on a scant two lines of text, one consisting of "flava, Emery" and a second with a reference to Emery (1914). It is easy to see why the name was overlooked for such an extended period of time.