Oxyepoecus plaumanni Kempf, 1974

Albuquerque, Nicolas Lavour de & Brandão, Carlos Roberto Ferreira, 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 49 (23), pp. 289-309 : 297-299

Oxyepoecus plaumanni Kempf, 1974

( Figs. 2 a-c, 7)

Oxyepoecus plaumanni Kempf, 1974:492 (worker and gyne descriptions); Bolton, 1995:301 (catalogue).

Worker (Holotype and individuals from several localidites, N = 30): t.l. = 2.10 (1.90-2.20); h.l. = 0.53 (0.48-0.55); h.w. = 0.43 (0.39-0.43); s.l. = 0.33 (0.31-0.33); m.l.e. = 0.07 (0.06-0.08); m.w.pr. = 0.31 (0.27-0.31); a.l. = 0.61 (0.55-0.61); h.f.l. = 0.36 (0.35-0.37); m.w.p. = 0.14 (0.12-0.14); m.w.pp. = 0.18 (0.16-0.18); c.i. 80 (77-81). Color chestnut brown. Integument smooth and shining, except longitudinal costulae between frontal carinae extending posteriorly almost to vertex, and laterally almost to eye; genae with few longitudinal rugae, none reaching the anterior eye margin, nor mandibular insertion; posterior third of pronotum disc and all mesonotum longitudinally costulate; mesopleuron longitudinally costulate, varying in degree of distinctness from well formed to almost effaced; basal face of the propodeum with transversal and shallow costulae barely attaining the spiracle laterally. Hairs moderately abundant, some long and erect; numerous subdecumbent or decumbent, curving mesad on cephalic dorsum, directed anteriorly on genae; erect and suberect on mesosomal dorsum; gastral hairs pointing posteriorly.

Head in Fig. 2a (f.f.v.): Mandible with basal border approximately equal chewing border, lacking broad diastema nor deep cleft between basal and subbasal teeth. Anterior apron of clypeus with prominent and laterally pointed denticle. Frontal carinae subparallel, extending to level of posterior margin of compound eye; maximum width between their outer edges approximately one fourth head width. Compound eye length almost equal to ocularmalar distance, with about 5-6 facets r.g.d.: less than 20 ommatidia. Scape fails to reach vertexal corner by distance greater than maximum scape width. Funnicular segment I as long as II-V combined, segments II-VII distinctly broader than long, VIII and IX as long as broad. Vertexal margin slightly concave.

Mesosoma in Fig. 2b (p.v.). Antero-dorsal corner of pronotum not carinate, transition between dorsal and lateral faces of the pronotum rounded. Metanotal groove not impressed (p.v.); dorsal profile of mesosoma continuous. Propodeum with basal face laterally immarginate; at meeting of basal and declivous faces one obliquely oriented (almost upward) tooth, which length subequal the half distance between its apex and the propodeal spiracle. Declivous face laterally weakly carinate.

Petiole in Figs. 2 b-c, node twice higher than long profile round, not compressed anteroposteriorly, nor laterally expanded, approximately half the width of the postpetiole (d.v.); subpetiolar process shaped as anterior blunt plate (p.v.); postpetiole very broad, antero-posteriorly compressed, subpostpetiolar process ventrally projects as posterior socket of the postpetiole.

Gyne: t.l. = 2.60-2.70; h.l. = 0.56-0.60; h.w. = 0.45-0.47; s.l. = 0.35-0.37; m.l.e. = 0.12; m.w.pr. = 0.40-0.41; a.l. = 0.75-0.78; h.f.l. = 0.40-0.43; c.i. 79-83. Color and pilosity as in worker. Sculpture on head as in worker. Pronotal dorsum with few very fine longitudinal costulae, which become more prominent laterally. Scutum smooth; scutellum longitudinally costulate; mesopleuron with very weak, almost indistinct, slightly oblique costulae; sides of metapleuron and propodeum costulate; costulae longitudinal ventrally, posteriorly oblique and curving dorsally. Sides of petiolar peduncle punctate posteriorly, otherwise smooth and shining. Three ocelli equal in size, diameter equal to minimum scape width. Fore wing with open radial cell (Rs not attaining the anterior margin), very small discoidal cell; free abscissa of M entirely lacking at apical field. Remaining characters as in worker.

Male: unknown.

Examined material: BRAZIL: Paraná: Porto Vitória (26°10’S, 51°12’W), x. 1959, 700 m, Plaumann, F. col., W.W.K. # 3209 (1 T paratype) ; Rio Azul [25°46’S, 50°41’W], x.1959, 1000 m, Plaumann, F. col., W.W.K. # 3189 (3 S paratypes) ; Tunas, Parque das Lauráceas (24°51’S, 48°43’W), 21-29.ii.2001, [R.R.] Silva and [F.] Eberhardt cols., transecto 1 Winklers 05, 10 and 19 (4 S); Rio Grande do Sul: Barão de Cotegipe [27°38’S, 52°15’W], vii.1960, Plaumann, F. col., W.W.K. # 3765 (1 S paratype) ; Boqueirão [29°30’S, 53°52’W], ix.1960, Plaumann col., W.W.K. # 3611 (1 S paratype) ; Erexim [27°38’S, 52°16’W], vii.1960, Plaumann, F. col., W.W.K. # 8097 (1 S holotype and 11 S paratypes); São Francisco de Paula, Floresta Nacional de São Francisco de Paula (29°23’S, 50°25’W), 03.vii.2002, Schmidt, F.A. col. (1 S) ; Santa Catarina: Blumenau [27°06’S, 49°09’W], P[arque] E[stadual] das Nascentes, 20-27.x.2000, Silva, R.R. and Eberhardt, F. cols., (2 S); Chapecó [27°06’S, 52°37’W], viii.1960, Plaumann, F. col., W.W.K. # 8331, 9883, (2 S paratypes) ; same locality, vii.1960, same collector (1 S paratype) ; same locality, vi, 1960 (1 S paratype) ; Ibicaré [27°06’S, 51°23’W], ix.1960, Plaumann, F. col., W.W.K. # 3247 (2 T paratypes) ; Linha Facão , v.1957, Plaumann, F. col., W.W.K. # 8178 (3 S paratypes) ; Palhoça, P[arque] E[stadual] Serra do Tabuleiro [27°44’S, 48°41’W], 02-10.vi.2003, Silva, R.R. and Dietz, B.H. cols., (1 S); P. Bormann, xii.1957, Plaumann, F. col., (1 T paratype) ; [Seara] Nova Teutônia [27°09’S, 52°18’W], vi.1960, Plaumann, F. col., W.W.K. # 8091 (1 S paratype) ; same locality, xii.1972, same collector, W.W.K. # 8557 (1 T paratype) ; same locality, xii.1972, same collector, W.W.K. # 8383 (1 T paratype) ; São Paulo: Botucatu [22°53’S, 48°26’W], 08.ix.1986, Forti, L.C. col. (1 S – soil trap); same locality, 07.xii.1987, Forti, L.C. and Rinaldi, I.M.P. cols (1 S); Cunha, P [arque] E[stadual] Serra do Mar (23°15’S, 45°00’W), 21-22.iv.2001, A.A. Tavares & R.R. Silva cols (4 S) .

Comments: In relation to the Oxyepoecus Rastratus species-group, O. plaumanni workers present exclusively the costulate sculpture between the frontal carinae, which do not reach the vertexal margin or laterally the compound eyes ( Kempf, 1974: Figs. 27, 28, 29 and 30).

In the original description, Kempf (1974) cited a paratype from Brazil, Rio Grande do Sul state, Tainhas [29°16’S, 50°18’W], collected in April. 1959, by F. Plaumann, (W.W.K. # 3247). However, although the pin and label are preserved in the MZSP collection, the specimen is missing from the triangle. We were not able to locate coordinates for Linha Facão, SC .

The distribution of O. plaumanni includes only localities at South and São Paulo State at Southeastern Brazil ( Fig. 7 ), both in dense evergreen and drier forests.

Figures

FIGURE 2: Scanning electron micrograph of the workers of O. plaumanni; a) head in full-face view; b) mesosoma in profile view; c) Petiole and postpetiole in dorsal view.

FIGURE 7: Map of distribution of O. plaumanni and O. rastratus.