Oxyepoecus crassinodus

Nothing is known about the biology of this species.

Identification
O. crassinodus is at once distinct by the deeply impressed metanotal groove and the thick, laterally scarcely expanded nor antero-posteriorly compressed petiolar node (Kempf 1974). See the nomenclature section for additional information.

Kempf (1974) - Differs from Oxyepoecus inquilinus in the shorter, triangular mandibles, the more abundant costulae on frons and vertex, the much smaller eyes with lesser number of ommatidia, the greater distance between mandibular insertion and anterior orbit of eyes, which exceeds noticeably the maximum diameter of the latter, the entirely sculptured mesopleura, the deeply impressed metanotal groove, the thick petiolar node which is not scalelike nor antero-posteriorly compressed.

The differences from the even closer Oxyepoecus daguerrei consist in the mostly smooth cephalic dorsum, the costulae on vertex being separated into two patches by a median, smooth longitudinal stripe, and do not attain posteriorly the occiput; in the smaller eyes with a lesser number of facets.

The following characters separate Oxyepoecus crassinodus from Oxyepoecus plaumanni: costulae on vertex and frons divided by a median smooth stripe; shoulders of thorax nearly completely rounded, not marked; promesonotum entirely smooth on disc; metanotal groove much more deeply impressed; transverse costulae on basal face of propodeum less dense and fewer in number (less than 15).

Distribution
Only known from Southern Brazil: Parana, Rio Grande do Sul, São Paulo and Santa Catarina.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil.

Biology
Nothing is known about the biology of this species.

Castes
Queens and males have not been collected.

Nomenclature

 *  crassinodus. Oxyepoecus crassinodus Kempf, 1974b: 482, figs. 2, 8, 15, 21 (w.) BRAZIL.



Worker
(holotype). Total length 2.7 (2.6) mm; head length 0.68 (0.64) mm; head width 0.55 (0.52) mm; scape length 0.41 (0.39) mm; maximum diameter of eyes 0.09 (0.08) mm; Weber's length of thorax 0.76 (0.70) mm; maximum width of pronotum 0.40 (0.37) mm; hind femur length 0.44 (0.43) mm; petiole width 0.20; postpetiole width 0.28 (0.31) mm; cephalic index 80 (82). Reddish brown; mandibles, legs, antennal club lighter, yellowish brown. Integument smooth and shining except for certain finely costulate portion on frons of head, basal face of propodeum and sides of thorax to be pointed out below. Hairs moderately abundant, standing on body, oblique on mandibles, antennae and legs; on head, besides the erect hairs on dorsum, also shorter, reclined hairs, curved obliquely mesad on front and vertex, forward on sides; fine pubescence present only on antennal club, coxae and tarsomeres.

Head. Mandibles triangular, not strikingly elongate, basal border scarcely longer than chewing border, basal tooth separated from the remaining teeth by a deeper cleft. Median apron of clypeus very strongly projecting forward between two strong (but weaker than in inquilinus) carinae, which form anteriorly a protruding and pointed tooth, each flanked laterally and somewhat below by another small, somewhat lobate denticle. Frontal area impressed, indistinctly delimited. Frontal carinae short, moderately expanded laterad, straight, parallel, terminating in front of level of anterior orbit of eyes, the distance between their outer edges (interfrontal width) conspicuously less than one third of head width, bearing dorsally a few fine costulae which diverge obliquely laterad above eyes and extend caudad beyond the level of the posterior orbit of eyes, but do not attain the occiput; the two patclies of costulae separated by a smooth median stripe on frons and vertex. Cheeks longitudinally costulate in front of eyes. The latter comparatively small, moderately convex, with about 5-6 facets in a row across the greatest diameter, the total number of ommatidia not exceeding 20. Antennal scape not reaching the occipital corner by a distance which surpasses its maximum width, when laid back over the head. Funicular segment I longer than both VIII and IX taken individually, as long a II-V combined; segments II-VII distinctly broader than long, VIII and IX not longer than broad.

Thorax. Promesonotum immarginate in front, dorsal disc transversely gently vaulted, passing through a narrow curvature to the slightly excavate laterotergite of pronotum; shoulders scarcely marked, neither subdentate nor tuberculate. Metanotal groove deeply impressed, forming a visible notch in profile, metanotal suture indicated. Promesonotum entirely smooth, with a few short longitudinal costulae on posterior half of mesonotum, starting from the metanotal suture forward. Mesopleura covered with fine, horizontal costulae, slanting downward posteriorly. Basal face of propodeum transversely costulate, 10-15 costulae fine, continuing obliquely downward and forward on sides of propodeum; the last dorsal costa between the small propodeal teeth not particularly prominent; declivous face smooth and shining, laterally sharply marginate, with at least two vestigial transverse costulae on upper half. Lower half of thorax posteriorly densely and horizontaly cosiulate, the costulae extending over the bulla of the metasternal gland.

Petiole strongly pedunculate, node thick and dorsally convex in both directions, antero-posteriorly scarcely compressed, much narrower than postpetiolc in dorsal view; subpetiolar process low, forming a sagittal keel terminating in front in a small tooth. Postpetiole very broad and scalelike, antero-posteriorly compressed, not as high as petiole, its posterior face with a few faint transverse costulae. Gaster slightly excised, smooth and shining above and below.

Type Material
Types. 6 workers, as follows: Brazil, Paraná State, Bocaiuva do Sul, XII-1963, F. Plaumann leg. 5 workers (WWK 8108, holotype and paratypes); Santa Catarina State, Nova Teutônia, Município de Seara, XII-1958, F. Plaumann leg. 1 worker (WWK 8308, paratype). All specimens taken as strays in sifted leaf-mold.

References based on Global Ant Biodiversity Informatics

 * Albuquerque N. L. and Brandão, C. R. F. 2004. A revision of the Neotropical Solenopsidini ant genus Oxyepoecus Santschi, 1926 (Hymenoptera: Formicidae: Myrmicinae). 1. The Vezenyii species-group. Papeis Avulsos de Zoologia (São Paulo) 44: 55-80.
 * Albuquerque, N.L. and C.R.F. Brandao. 2009. A revision of the Neotropical Solenopsidini ant genus Oxyepoecus Santschi, 1926 (Hymenoptera: Formicidae: Myrmicinae): 2. Final. Key for species and revision of the Rastratus species-group. Papéis Avulsos de Zoologia (São Paulo) 49(23): 289-309.
 * Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
 * Favretto M. A., E. Bortolon dos Santos, and C. J. Geuster. 2013. Entomofauna from West of Santa Catarina State, South of Brazil. EntomoBrasilis 6 (1): 42-63.
 * Kempf W. W. 1974. A review of the Neotropical ant genus Oxyepoecus Santschi (Hymenoptera: Formicidae). Studia Entomologica 17: 471-512.
 * Rosa da Silva R. 1999. Formigas (Hymenoptera: Formicidae) do oeste de Santa Catarina: historico das coletas e lista atualizada das especies do Estado de Santa Catarina. Biotemas 12(2): 75-100.
 * Rosumek, F.B., M.A. Ulyssea, B.C. Lopes, J. Steiner. 2008. Formigas de solo e de bromélias em uma área de Mata Atlântica, Ilha de Santa Catarina, sul do Brasil: Levantamento de espécies e novos registros. Revista Biotemas 21(4):81-89.
 * Silva R.R., and C. R. F. Brandao. 2014. Ecosystem-Wide Morphological Structure of Leaf-Litter Ant Communities along a Tropical Latitudinal Gradient. PLoSONE 9(3): e93049. doi:10.1371/journal.pone.0093049
 * Ulyssea M. A., C. R. F. Brandao. 2013. Catalogue of Dacetini and Solenopsidini ant type specimens (Hymenoptera, Formicidae, Myrmicinae) deposited in the Museu de Zoologia da Universidade de Sao Paulo, Brazil. Papies Avulsos de Zoologia 53(14): 187-209.