Gnamptogenys rugimala Marcineiro & Lattke, 2020

Marcineiro, Frederico S. R. & Lattke, John, 2020, A new species of the Gnamptogenys Mordax subgroup (Hymenoptera: Formicidae), with an Identification key to the species within the subgroup, Revista Brasileira de Entomologia (e 20190011) 64 (2), pp. 1-4 : 2-3

Gnamptogenys rugimala Marcineiro & Lattke , new species

urn:lsid:zoobank.org:act:F06276EC-241A-40F6-BA3F-ED3F30E6574C

Type material. Holotype: Brazil, São Paulo, Salesópolis, E.B.B. , 5-7. vii.1997, C. I. Yamamoto. Transect 1; Winkler 10. Specimen identifier DZUP 548842 . One worker deposited in the MZSP collection, São Paulo, Brazil . Paratype: 1 worker, Brazil, Paraná, Tunas, Parque das Lauráceas , -24.8544° -48.7167°, 21-29.ii.2001, Silva & Eberhardt. Transecto 1; Winkler 24. Specimen identifier DZUP 548843 . One worker deposited in the MZSP collection, São Paulo, Brazil .

Etymology. The species epithet is derived from the Latin noun for jawbone, mala, and the Latin noun for crease or wrinkle, ruga.

Diagnosis. Within the mordax subgroup this species is recognized by the dorsum of the mandible with striae/rugae on at least one fourth of the mandible length; relative small eye size (OI <11); broad pronotal-anepisternal suture; second gastral tergite smooth and shining.

Worker description. Measurements and Indices. Holotype: HL- 1.04mm; HW- 0.92mm; ML- 0.39mm; WL- 1.41mm; SL- 0.65mm; EL- 0.10mm;CI- 88.23; SI- 71.11; MI- 37.25;OI- 9.80. Paratype:HL- 1.14mm; HW- 0.98mm; ML- 0.47mm; WL- 1.63mm; SL- 0.74mm; EL- 0.12mm; CI- 86; SI- 76; MI- 41; OI- 11.

Head in dorsal view rectangular, posterior cephalic margin slightly concave, lateral margin straight to weakly convex, head slightly wider anteriorly than posteriorly; clypeus with anteromedian projection slightly wider than distance between frontal lobes, anterior margin of projection sinuous with broad median concavity and lateral convexity that extends posteriorly to rest of clypeus, clypeal lamella very narrow, best seen in anteroventral view of clypeus. Labrum with median concavity at apex, dorsal surface transversely imbricate, prementum smooth and shining, stipes with median rugulose sulcus; hypostoma finely imbricate. Cephalic dorsum and vertex longitudinally costate with sparse piligerous punctae, individual costula smooth and shining. Scape dorsoventrally flattened, failing to reach posterior cephalic border by slightly more than one apical width, dorsum smooth and shining with sparse punctulae. Mandible elongate, semifalcate, with broad basal convexity, internal and masticatory margins only distinguishable from one another by absence of teeth on internal margin, masticatory margin with series of low blunt denticles, better observed in oblique ventral view of mandible; dorsum with narrow band of rugulae and elongate punctae bordering masticatory margin from base to midlength of mandible, medioapically mostly smooth. Cephalic vertexal face concave, meeting dorsum at blunt angle; eye small, 6-8 ommatidia long, set just posterad to midlength of lateral cephalic margin in lateral view; ventral cephalic face with broadly diverging costulae.

Mesosoma in lateral view with slightly convex dorsal margin, metanotal groove shallow but distinct, propodeal dorsum bends onto declivity by approximate right angle; cervical shield rugose, pronotal dorsum and lateral face longitudinally costate; propleuron transversely striate; mesosomal dorsum continuously longitudinally costate; katepisternum longitudinally costulate; anterior two-thirds of metapleuron mostly shining with weak undulations, posterior one-third longitudinally costate, width of metapleuron relatively uniform. Space between anepisternum and posterolateral pronotal margin, relatively broad; anepisternum mostly rugulose, reduced to a narrow elevated strip extending obliquely ventrad from metathoracic spriacle to same height as dorsalmost margin of katepisternum.Propodeal spiracle facing slightly posteriorly, situated three opening diameters from propodeal declivitous margin.Mesometapleural suture well-impressed,scrobiculate; metapleural-propodeal suture indistinct; propodeum with narrow lateral crest; propodeal declivity longitudinally costate anteriorly and transversely costate posteriorly, forming an upside-down layered “T”.

Petiole with short peduncle; in lateral view low, subquadrate, anterior margin oblique, broadly concave, dorsal margin slightly convex, posterior margin vertical, broadly convex; anterior face rugose, laterally and dorsally with longitudinal costae; posterior face narrow and transversely costate. Subpetiolar process in lateral view trapezoid, with longest base attached to sclerite, anterior margin broadly convex, ventral margin broadly concave and posterior margin almost straight; surface irregularly areolate.Anterior face of abdominal tergite III mostly smooth, dorsal and lateral faces longitudinally costate; abdominal sternite III with slightly weakened costae laterally, smooth and shining centrally with sparse punctae; rest of gastral segments smooth and shining with sparse punctulae. Procoxa transversely costate in lateral view, meso and metacoxa rugose; metacoxa with low dorsal lobe. Tibiae and femora mostly smooth and shining with sparse punctulae; probasitarsal notch with dense row of hairs and single median seta.

Head, thorax, dorsum of petiole and gaster without basal pubescence, with sparse erect to suberect yellow hairs, abundant pilosity on posterior gastral segments. Dorsum of antennal scape mostly devoid of pilosity except for posterior and anterior margins with subdecumbent hairs shorter than scape width. Antennae and legs yellowish brown to ferruginous; mandible brown; head, thorax and abdomen ferruginous brown to dark brown, sides lighter colored than dorsum, head dark brown to black.

Geographic range

This species is only known from the states of São Paulo and Paraná, southeastern Brazil.

Biology

Both ants were captured using Winkler extractors. Both of them came from an Atlantic forest region, classified as Cfb on Köppen climate classification, with annual rainfall of 1,550 mm and average temperature of 17°C through the year ( Alvares et al., 2014). According to IBGE (2019), these areas are defined as Floresta Ombrófila Densa Montana in association with secondary vegetation. This vegetation is found in altitudes ranging from 400 to 1.000 meters and generally has a thin soil layer, bearing trees of 20 meters height on average, with small leaves and thin trunks. Both specimens were found at an approximate altitude of 850 m