Oxyepoecus ephippiatus, Albuquerque, Nicolas Lavor De & Brandão, Carlos Roberto F., 2004

Albuquerque, Nicolas Lavor De & Brandão, Carlos Roberto F., 2004, A Revision Of The Neotropical Solenopsidini Ant Genus Oxyepoecus Santschi, 1926 (Hymenoptera: Formicidae: Myrmicinae). 1. The Vezenyii Species- Group, Papéis Avulsos de Zoologia 44 (4), pp. 55-80 : 64-66

Oxyepoecus ephippiatus sp. nov.

( Figs. 2 a-c)

Oxyepoecus ephippiatus Albuquerque and Brandão. Holotype worker, Brasil: Amazonas : Manaus, Rs 1301 [01°30’S 46°11’W], 16.xii.[19]93, A.B. Casimiro [col.] # H-49, deposited in INPA.

Paratypes: worker. Brasil: Amazonas : Manaus, 29.ix.[19]93, A.B. Casimiro [col.] # 2306, deposited in MZSP (coated with gold for SEM examination) [paratype incomplete, just the mesosoma and petiole]. Gyne. Brasil: AM : Manaus, Rs 1104, 16.xii. [19]93, A.B. Casimiro [col.] # L-9, deposited in MZSP .

Etymology: Refering to the saddle shape of the propodeum (Latin: ephippium = saddle).

Worker: Holotype and paratype within brackets t.l.= 2.62 (2.57); h.l.= 0.58 (0.58); h.w.= 0.49 (0.49); s.l.= 0.40 (0.38); m.l.e.= 0.10 (0.10); m.w.pr.= 0.41 (0.41); a.l.= 0.74 (0.74); h.f.l.= 0.49 (0.48); m.w.p.= 0.32 (0.31); m.w.pp.= 0. 34 (0. 31); c.i. 84 (84). Color ferruginous brown. Integument smooth and shining, with the following exceptions: frontal carinae with 4-6 short but well formed costulae that are not prolonged posteriorly, ending before the level of the inferior orbits of the compound eyes; genae with few longitudinal short rugae that do not reach the inferior orbit of the compound eyes; promesonotum smooth and shining; dorsal face of the propodeum with 6-8 well marked transverse costulae that cover the metapleural region; declivous face smooth and shining. Hairs abundant, long, but without a regular orientation on head, suberect and relatively curved anteriorly on pronotal dorsum, mesonotum and petiolar node; suberect, but curved backwards on the postpetiole.

Head as shown in Fig. 2a (f.f.v.). Mandibles relatively elongated, with a broad and shallow diastema between the basal and subbasal teeth. Anterior teeth of clypeus with lateral blunt and scarcely developed denticles. Frontal carinae gently convex, with the posterior ends at the level of the middle of the compound eyes, the maximum width between their outer edges approximately two fifths of the head width. Compound eyes medium sized, with about 6-8 facets r.g.d., which is almost equal to the distance between the anterior orbit and the mandibular insertion: total number of ommatidia about 30. Antennal scape failing to reach the occipital corner by a distance approximately equal to the maximum thickness of the scape. Funicular segment I as long as II-V combined, segments II-VII distinctly broader than long, VIII and IX as long as broad.

Mesosoma as shown in Fig. 2b (p.v.). Pronotum shoulders not at all marked, sides of the pronotum completely rounded. Metanotal groove not at all impressed with the mesosoma in profile. Propodeum very modified, with the shape of a pronounced horse saddle, the level of the dorsal face much higher than the level of the rest of the mesosoma, dorsal face of the propodeum immarginate on sides; posteriorly with two medium sized teeth. Declivous face laterally weakly marginate and carinate.

Petiole as shown in Figs. 2 b-c, node high and round, antero-posteriorly compressed and laterally expanded in a scalelike fashion, almost with the same width as the postpetiole (d.v.); subpetiolar process with an anterior end as a prominent and blunt tooth directed obliquely forwards (p.v.). The postpetiole very broad, antero-posteriorly compressed, the subpostpetiolar process forming a small and continuous plate with its ventral margin bearing three regularly spaced minute notches.

Gyne: t.l.= 3.32; h.l.= 0.69; h.w.= 0.58; s.l.= 0.35; m.l.e.= 0.21; m.w.pr.= 0.55; a.l.= 0.88; h.f.l.= 0.61; m.w.p.= 0.35; m.w.pp.= 0.34; c.i. 84. Color chestnut ferruginous brown. Integument almost as in the conspecific workers, with the following exceptions: genae rugae almost reaching the inferior orbit of the compound eyes; scutellum weakly marginate and smooth and shining; Propodeum as in the workers, although the level of the dorsal face is similar to the level of the scutellum. Hairs as in the workers.

Head (f.f.v.) more elongate than in the workers, occipital corners broadly rounded. Compound eyes with 12-14 ommatidia r.g.d. and a total of approximately 70 ommatidia. Ocelli equally developed, very small, with the same diameter of the thinnest part of the antennal scape. The antennal scapes when laid back over the head as much as possible, almost attaining the occipital border. Funicular segment as in the workers.

Petiolar node, in relation to that of the workers, more antero-posteriorly compressed.

Male unknown.

Diagnosis, distribution and comments

The exclusive character of the workers of O. ephippiatus is the very modified shape of the dorsal face of the propodeum (saddle shaped) with its level elevated in regard to the rest of mesosoma. O. ephippiatus was found in only one locality in the Amazonian Region (fig. 8).

O. ephippiatus gyne runs near those of O. vezenyii in Kempf ’s key (1974), however its propodeum is different, as discussed above.

Examined material: Brasil: Amazonas : Manaus [01°30’S 46°11’W] (2 Ψ: holotype and paratype, see comments on paratype; 1 ♀ paratype) .

Figures

FIGURE 2. Scanning electron micrograph of the workers of O. ephippiatus; a) head in full-face view;b) mesosoma in profile view; c) petiole in dorsal view.