Anochetus siphneus

So far as known, Anochetus siphneus is restricted to the West African forest belt, where it is found in the leaf litter or humus of the forest floor, and in rotten wood on the ground (Brown 1978).

Identification
Brown (1978) - Formerly, I had thought this species might be the same as Anochetus jonesi, but a direct comparison of type material shows that jonesi is larger, has relatively larger eyes, and has a blunter, more narrowly rounded petiolar apex as seen from the side. Perhaps A. siphneus has been confused in the past also with Anochetus talpa; I suspect that the A. talpa recorded by Santschi 1914b: 331 from Ibadan, Nigeria, may really be A. siphneus, but I have not studied Santschi's specimen. A. talpa (syntypes in ) is likewise a very small yellow species with dot-like eyes of perhaps 7 facets, but the petiolar node is only feebly tapered apicad as seen from the side, and its summit is considerably more broadly rounded even than in A. jonesii.

A. siphneus is perhaps most closely related to Anochetus grandidieri and allies, but within this group, ties are obscure. It differs from Anochetus punctaticeps, which is similar in color, by its smaller eyes, slightly larger body size, narrow transverse mesonotal disc, emarginate nodal apex, and by the more abundant erect hairs on the gastric dorsum.

Distribution
Known from Ivory Coast, Nigeria and Ghana.

Distribution based on Regional Taxon Lists
Afrotropical Region: Ethiopia, Ivory Coast.

Castes
Queen and male unknown.

Nomenclature

 * . Anochetus siphneus Brown, 1978c: 608, figs. 11, 19 (w.) IVORY COAST, GHANA, NIGERIA.
 * Type-material: holotype worker, 3 paratype workers.
 * Type-locality: holotype Ivory Coast: Bandama River, Station Scientifique de Lamto, berlesate (W.H. Gotwald & R. Schaefer); paratypes: 1 worker Ivory Coast: Banco Forest, nr Abidjan (W.L. Brown), 1 worker Ghana: Tafo (= New Tafo, Eastern Region, Akim District, Cocoa Research Institute of Ghana), 16.vii.1970, on mud under dead leaf (B. Bolton), 1 worker Nigeria: Gambari (= Cocoa Research Institute of Nigeria), under fallen banana stem (B. Bolton).
 * Type-depositories: MCZC (holotype); BMNH, MCZC (paratypes).
 * Status as species: Bolton, 1995b: 65.
 * Distribution: Ghana, Ivory Coast, Nigeria.

Worker
Holotype, worker: TL 4.4, HL 1.12, HW 0.96, ML 0.52, WL 1.27, scape L 0.84, eye L 0.06 mm; CI 86, MI 46.

Paratypes, 3 workers: TL 4.0-4.5, HL 1.04-1.14, HW 0.92-1.00, ML 0.50-0.55, WL 1.24-1.35, scape L 0.80-0.86, eye L 0.06-0.10 mm; CI 86-91, MI 46-49.

Medium yellow; middle of dorsum of head slightly darker.

A small member of the grandidieri group with eyes reduced to dots of only about 7-15 facets, filling less than half the length of the orbital fossa. Scape fails to reach posterior border of occipital lobe by about the length of the first funicular segment (less in 2 paratypes); segments II, III and IV of funiculus longer than broad, subequal in length, together longer than I. Mandibles robust; preapical excision feeble, preapical angle low, rounded. Posteromedian impression wide and deep, shining, almost impunctate; nuchal carina in full-face view broadly V-shaped, with rounded apex.

Frontal striation continuing back onto the vertex for only a short distance beyond the midlength of the head, but replaced on the posterior disc of the vertex by dense, sometimes contiguous, coarse and fine punctures that surround the posteromedian impression; head otherwise smooth and shining.

Trunk compact, with the 2 sutures deeply impressed and longitudinally costulate at bottom. Pronotum with the usual fine margin around its anterior slope, paralleled by a narrow belt of fine, irregular rugulation or striation. Mesonotal disc narrow, straplike, about 3 times as broad as long. Dorsum of propodeum finely rugulose, weakly shining anteriad, otherwise opaque; discs of pro- and mesonotum and sides of trunk generally smooth and shining, as are also petiolar node and gastric dorsum. Node as in fig. 19; the paratypes are like this also except for the specimen from Gambari, Nigeria, which has the apical margin almost straight, with only a faintly concave tendency as seen from the front.

Pubescence short, appressed, moderately abundant on head, appendages and gaster, sparse and dilute on pronotum; the usual pair of erect hairs on the front of the pronotum, also 4 pairs of short, erect hairs straddling the cephalic midline: 2 pairs on frontal carinae, and 2 pairs on vertex. Gaster with up to about 25 coarse, stiff, pasteriorly-inclined, pointed hairs on the dorsum, 6-8 of these on first tergum.

Type Material
Holotype a single worker from the gallery forest of the Bandama River at the Station Scientifique de Lamto, south central Ivory Coast, in a berlesate of leaf litter and humus, W. H. Gotwald and R. Schaefer.

Paratypes (MCZC, ) 3 workers: Ivory Coast, Banco Forest, near Abidjan, W. L. Brown; Ghana, Tafo, on mud under dead leaf, B. Bolton; Nigeria, Gambari, under fallen banana stem, B. Bolton.

References based on Global Ant Biodiversity Informatics

 * Belshaw R., and B. Bolton. 1994. A survey of the leaf litter ant fauna in Ghana, West Africa (Hymenoptera: Formicidae). Journal of Hymenoptera Research 3: 5-16.
 * Belshaw R., and B. Bolton. 1994. A survey of the leaf litter ant fauna in Ghana, West Africa (Hymenoptera: Formicidae). Journal of Hymenoptera Research. 3: 5-16.
 * Braet Y., and B. Taylor. 2008. Mission entomologique au Parc National de Pongara (Gabon). Bilan des Formicidae (Hymenoptera) recoltes. Bulletin S. R. B. E./K.B.V.E. 144: 157-169.
 * Brown W.L. Jr. 1978. Contributions toward a reclassification of the Formicidae. Part VI. Ponerinae, tribe Ponerini, subtribe Odontomachiti. Section B. Genus Anochetus and bibliography. Studia Ent. 20(1-4): 549-638.
 * Kone M., S. Konate, K. Yeo, P. K. Kouassi, and K. E. Linsenmair. 2012. Changes in ant communities along an age gradient of cocoa cultivation in the Oumé region, central Côte dIvoire. Entomological Science 15: 324339.
 * Yeo K., S. Konate, S. Tiho, and S. K. Camara. 2011. Impacts of land use types on ant communities in a tropical forest margin (Oumé - Cote d'Ivoire). African Journal of Agricultural Research 6(2): 260-274.
 * Yeo K., T. Delsinne, S. Komate, L. L. Alonso, D. Aidara, and C. Peeters. 2016. Diversity and distribution of ant assemblages above and below ground in a West African forest–savannah mosaic (Lamto, Cote d’Ivoire). Insectes Sociaux DOI 10.1007/s00040-016-0527-6