Description of a new ecuadorean gnamptogenys species (hymenoptera: formicidae), with a discussion on the status of the alfaria group

Abstract

-A new Ecuadorean species of Gnamptogenys Roger of theAlfaria group is described based upon a worker holotype and a dealated queen paratype. Gnamptogenys vriesi, n. sp. belongs to a subgroup of the Alfaria group, which includes also G. simulans, G. bufonis, and G. fakifera. The other subgroup includes G. minuta, G. pneodonax, G. striolata, and possibly, G. caelata. We present a characterization of the Alfaria group and its subgroups, and a discussion on the status of the group. Brown (1958) in a revision of the ponerine ant tribe Ectatommini synonymized several genera and subgenera with Gnamptogenys Roger, stating that this genus and its synonyms constitute the "upper ectatommines." According to him the species of Gnamptogenys fall into four groups: Gnamptogenys s. str., Holcoponera and Alfaria (the three from the New World), and Stictoponera (Old World). Within each group it is safe to consider the genera synonyms, albeit the assignment of all these generic and subgeneric names to the synonymy of Gnamptogenys was "set down with the greatest reluctance, and with the hope that some future study based on better material may establish a clear division of the species" (Brown, 1958). New material of Gnamptogenys has accumulated in collections at a relatively slow pace, as these terrestrial ants are often difficult to see against the substrate. Never theless the "Museu de Zoologia da Universidade de Sao Paulo" (MZUSP) recently received two important collections of Ecuadorean soil ants, including a new Gnamp togenys species of the Alfaria group, which is described below. Alfaria was described by Emery (1896) from workers, queens and a male of A. simulans, collected by A. Alfaro at Suerre, near Jimenez, Costa Rica. While the paper was in press Emery added another species, A. minuta, described from two alate queens collected in the Bolivian Chaco (received from "Casa Staudinger e Bang Haas"). Mann (1926) described A. bufonis from a single "worker" taken from a stomach of a Bufo valliceps specimen, collected by Nelson and Goldman in July, 1894 at Choapan, Oaxaca, Mexico. Borgmeier (1957) described A. striolata based on two workers collected by Fritz Plaumman in October, 1956 at Nova Teutonia, state of Santa Catarina, southeastern Brazil. Alfaria mus Santschi, 1931 (Panamas: French Field); A. emeryi Forel, 1910 (Co lombia: vic. Dibulla); A. panamensis Weber, 1940 (Panama: Barro Colorado Island); Opisthoscyphus scabrosus Mann, 1922 (Honduras: Lombardia) and A. carinata We This content downloaded from 157.55.39.159 on Fri, 09 Dec 2016 05:42:22 UTC All use subject to http://about.jstor.org/terms 490 JOURNAL OF THE NEW YORK ENTOMOLOGICAL SOCIETY Vol. 98(4) ber, 1940 (British Guiana: Forest Settlement, Mazaruni River) were all correctly synonymized with Gnamptogenys minuta by Brown (1958). After Brown's (1958) revision, three more Gnamptogenys species which fit into the Alfaria group concept were described by Kempf: G. caelata described in 1967(a) from an unique worker collected at Iguacu, state of Paranfa, southeastern Brazil by F. Plaumman; G. falcifera, described in 1967(b) from a female collected at Tingo Maria, Peru by William L. Brown, Jr., and G. pneodonax, described in 1968 from a worker taken in Benjamin Constant, Brazilian Amazon by Karol Lenko. Two additional species, both from Venezuela, remain to be published (Lattke, in press). All these species share with the one we are describing the inflated second gastric segment (not so extremely vaulted in G. striolata), and a greater development of the frontal lobes than in other Gnamptogenys species. In the Alfaria group the frontal lobes are higher and more expanded laterally and anteriorly; as a consequence the base of the scape and the articular condyle are not so easily observable. Also particular to the Alfaria group is the presence of a carina that briefly borders the anterolateral regions of the antennal fossa, distinct from the neighboring sculpture. Despite these differences we see no cause for resurrecting Alfaria as a genus. The discovery and description of G. striolata was fundamental in relating this group with the rest of Gnamptogenys (Brown, 1958:222). Also Kempf (1 967a) while describing G. caelata comments that it is "somewhat intermediate between striolata and the more orthodox species of Gnamptogenys." NOTES OF MEASUREMENTS All measurements were obtained under 40 x magnification. Head width was ob tained across eyes (HWE) and just in front of the eyes (HW). The mandibular length (MLC) is represented by the chord between the externo-lateral clypeo-mandibular limit to the apex of the apical tooth. The scape length is taken from the visible part of the scape, as the frontal lobes completely cover the scape insertion and condylus, to the apex; (ED) represents the compound eye diameter. The petiolar (PL) and postpetiolar (PpL) were taken in dorsal view. Gnamptogenys vriesi, new species Figs. 1-7 Diagnosis. Similar to G. simulans, G. bufonis, and G. falcifera, from which it differs in measurements (WL > 3.00 mm) and the following characters: anterior border of clypeus conspicuously concave: compound eyes bulging and with more than 20 facets in eye diameter, interrupting the head profile in full face view; metanotal groove deeper; propodeal spiracles circled by a conspicuous lighter band and bulging; pro podeum declivity more deeply impressed; foramen circled by a raised margin (Fig. 4); and anterodorsal margin of petiole raised. The paratype queen is very similar to the worker holotype, though slightly smaller (see measurements) and with the normal caste differences, i.e., three ocelli (the pos terior ones may be confused with the surrounding foveolae, but bear visible lenses), complete alitrunk with parapsidal sutures and the arm of the notaulus. The extra tooth of each tarsal claw is less developed in the queen than in the worker. Etymology. The specific name is a patronym in honor of the collector of the types. This content downloaded from 157.55.39.159 on Fri, 09 Dec 2016 05:42:22 UTC All use subject to http://about.jstor.org/terms