Gnamptogenys vriesi

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Gnamptogenys vriesi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ectatomminae
Tribe: Ectatommini
Genus: Gnamptogenys
Species: G. vriesi
Binomial name
Gnamptogenys vriesi
Brandão & Lattke, 1990

Gnamptogenys vriesi F2.jpg

Gnamptogenys vriesi F3.jpg

Specimens from Ecuador have abundant dirt and organic matter covering most of their body except for the cephalic and gastral ventral areas, implying foraging or nesting in the soil. These findings in southern Ecuador extend the range of this species by nearly 135 km to the South-West. (Lattke and Delsinne 2016)

Identification

Brandao and Lattke (1990) - This species is similar to Gnamptogenys simulans and Gnamptogenys falcifera, from which it differs in measurements (WL>3.0mm)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; propodeum declivity more deeply impressed; foramen circled by a raised margin; and anterodorsal margin of petiole raised.

The body surfaces of Gnamptogenys simulans, Gnamptogenys falcifera and Gnamptogenys vriesi share a characteristic sculpturing; except for the legs, mandibles, anterolateral portions of frontal lobes and anterior portion of clypeus; very finely striolate and mostly covered by piligerous foveolae. In G. vriesi the fovolae are nearly contiguous and the stiolation can be seen only at high magnifications at the confluence of the depressions. From each foveola departs an eccentric hair, which is turned in different directions, depending on the area of the body. G. simulans and G. facifera may have extensive areas smooth and shining, but it G. vriesi the foveolae cover all body surfaces, except the cited ones. The holotype worker of the latter had these foveolae filled with earth, in a manner similar to that found by Holldobler and Wilson (1986) in Basiceros and Stegomyrmex (Myrmicinae).

The propodeal declivity in the three species bears a crested depression, completely sculptured with radiate punctations, clearly centered at the foramen in the new Ecuadorean species, but faintly visible in the previously described ones. These combined features distinguish these species from other taxa described as Gnamptogenys and also from other species of the Alfaria group. They may be considered thus as forming a distinct subgroup of the Alfaria group.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Ecuador (type locality).


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Morphology

Lattke and Delsinne (2016) - The eye structure in G. vriesi appears quite different from other Gnamptogenys minuta group ants, and from most insects in general, by having the cuticle surrounding the eye forming a smooth, transparent convex structure, appearing as a single fishbowl-shaped lens with what seem to be very faint traces of individual facets formed by corneal lens, visible by SEM with a magnification of 180× and more. Corneal lens molded into individual facets are explicitly visible in both the reduced eyes of G. minuta and the large eyes of G. simulans. A compound eye with few, or an apparent single facet, is frequent in insects with reduced eyes (e.g., in Dorylinae; Werringloer 1932), but the bulging eyes of G. vriesi can hardly qualify as reduced. Separated beneath this fishbowl-like structure the apparent ommatidia are clearly visible. This state is shared not only by the present specimens but also by the holotype in the São Paulo Museum. Since the corneal lens is formed by the cuticle itself, this morphology opens questions such as is the crystalline cone separated from the corneal lens or is the corneal lens itself separated into different layers? Perhaps it is simply a postmortem artefact.

Castes

Described from workers and queen. Males are unknown.

Worker

Queen

The paratype queen is very similar to the worker holotype, though slightly smaller and with the normal caste differences, i.e., three ocelli (the posterior ones may be confused with the surrounding fovolae, but bear visible lenses), complete alitrunk with parapsidal sutures and the arm of the notalus. The extra tooth of each tarsal claw is less developed in the queen than in the worker.

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • vriesi. Gnamptogenys vriesi Brandão & Lattke, 1990: 490, figs. 1-7 (w.q.) ECUADOR.
    • Status as species: Lattke, 1992a: 128; Bolton, 1995b: 211; Lattke, et al. 2007: 264 (in key); Lattke & Delsinne, 2016: 142 (redescription).

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Lattke and Delsinne (2016) - HL 1.95, HW 1.87 (posterad to eye), SL 1.77, ED 0.35, WL 3.03, PL 1.23 (in dorsal view); CI 0.96, SI 0.95, OI 0.19. Specimen 2: HL 1.93, HW 1.82, SL 1.84, ED 0.36, WL 3.00, PL 1.20; CI 0.94, SI 0.95, OI 0.18.

Head subquadrate in full face view; posterior cephalic margin straight, lateral margin straight to weakly convex; anterolateral cephalic margin slightly bulging. Frons with a median longitudinal slit that extends from the supraclypeal area to the height of the eye posterior margin. Eye semi-spherical, placed close to cephalic mid-length; frons with abundant foveolae, diameter of each depression usually greater than width of intervening space. Each foveola with an eccentric hair, which turned in different directions, depending on the area of the head. Integument between depressions very finely striate with silky sheen; bottom of foveolae with more impressed and more spaced strigae. Clypeal disc smooth with some foveolae, frontal lobe foveolate and silky mesad but toward lateral margin without depressions, mostly smooth with weak striae. In dorsal view, frontal lobe greatly expanded laterad, covering all of scape base, including condyle and neck. Mandible shining, triangular and elongate, longitudinally striate with an edentate masticatory margin. Palps not visible.

Anteromedian clypeal margin concave, overhanging lateral clypeal margin, which is concave mesad and convex laterad. No anterior clypeal lamella. Antennal scape projects beyond posterior cephalic margin by at most one-fourth its length, shining with fine longitudinal striae and punctures at the base of abundant suberect white to golden hairs. In lateral view occipital lobe well-developed, with bluntly angular ventral margin. Cephalic ventrum also foveolate, with intervening space covered with longitudinal or transverse striae more impressed than on the dorsal area. Anterior part of hypostome forms small blunt projection. Compound eye round, semispherical with smooth and transparent outer surface, physically separated from convex grouping of apparent ommatidia by a space.

Mesosomal dorsal margin in lateral view with promesonotum forming one convexity and propodeum another; promesonotal suture not visible; metanotal groove clearly impressed. Cuticle silky with dense piligerous foveolae, progressively vanishing on metapleuron. Pronotum anterolaterally with depression that mirrors cephalic occipital lobe. Mesometapleural suture well-impressed, anepisternum clearly separated from katepisternum. Metapleural gland opening forming a transverse slit. Bulla distinct as low swelling. Propodeal spiracle slightly bulging, round, surrounded by light brown rim, and separated from posterior margin by one diametre or less. Propodeal declivity opaque, very finely granulose with hints of striolae; surrounded by lamellate, inverted U-shaped crest.

Petiolar node relatively low and evenly convex, without differentiated posterior face, foveolate; anteroventral process of petiole shaped as low rounded lobe. Postpetiolar ventral margin sinuate in lateral view, a longitudinal crest extends from prora to posterior margin of abdominal sternite III; dorsal margin mostly weakly convex in lateral view, most convex posterad. Cinctus present between petiole and abdominal segment III, and between abdominal segment III and IV. Abdominal segment IV with dorsal margin extremely convex, bulging such that apex faces anteroventrally; sternite IV convex. Abdominal sternites IV to apex form concavity in lateral view. Gaster mostly foveloate, shallow on abdominal sternite III. Body dark brown with abundant white to golden stiff hairs; welldeveloped sting. Hindcoxa with low, blunt, and outward projected tubercle. Coxae with transverse striolae, femora dorsally longitudinally striolate, ventrally transverse, tibiae longitudinally striolate. One simple spur each on meso- and metatibiae. Claws with well-developed basal tooth.

Type Material

Types: Worker (holotype) and dealated queen (paratype) collected at Ecuador: prov. Morona-Santiago: Los Tayos (03 08'S, 78 14'W) 3 July 1976 by Tjitte de Vries. Collection numbers VIII-4 (holotype) and I-16 (paratype). Holotype and paratype deposited at Museu de Zoologia da Universidade de Sao Paulo (MZSP).

Etymology

The specific name is a patronym in honor of Tjitte de Vries who collected the types.

References