Leptogenys carioca, López-Muñoz & Villarreal & Lattke, 2018

López-Muñoz, Román A., Villarreal, Erick & Lattke, John E., 2018, Two new species of Leptogenys from southern Brazil (Hymenoptera: Formicidae), Zootaxa 4410 (3), pp. 559-566 : 563-564

Leptogenys carioca n. sp.

urn:lsid:zoobank.org:act:54215E50-5245-4BBC-A56D-0B1EBE2F349B Fig. 2

Worker diagnosis. Apex of median clypeal lobe blunt, not acutely pointed; pronotal dorsum mostly smooth and shining with sparse punctae and undulations, mesonotum mostly smooth with abundant punctae, mesopleuron with abundant transverse rugulae which grade into striae, anterior propodeal dorsum and metanotum transversely rugulose—punctate, posterior propodeal dorsum mostly smooth and shining with sparse punctae.

Examined material. Holotype: Brazil, Rio de Janeiro, P. N. Itatiaia, 1991m, 22°24’41.90”S, 44°38’18.84”W, 20.I.2015, Lasmar et al. col. Projeto Gradiente Altitudinal. Mata Atlântica—Transecto 6A, Pitfall Epigéico Ponto: 4 B. Deposited in DZUP with unique specimen identifier DZUP 548779 . Paratype: Brazil, Rio de Janeiro, P. N. Itatiaia, 2000m, 22°24’37.43”S, 44°38’17.10”W, 20.I.2015, Lasmar et al. col. Projeto Gradiente Altitudinal. Campo de Latitude—Transecto 6B, Pitfall Epigéico Ponto: 4 A. One point-mounted worker deposited in MZSP with unique specimen identifier DZUP 548780 .

Worker dimensions, Holotype (Paratype): HL 1.88 (1.80); HW 1.06 (1.00); ML 0.84 (0.78); EL 0.38 (0.38); SL 2.00 (1.97); PW 1.00 (0.97); WL 2.94 (2.91); PH 1.00 (1.00); PL 1.14 (1.13); DPW 0.63 (0.59) mm. CI 0.57 (0.56); MI 0.79 (0.78); OI 0.35 (0.38); SI 1.88 (1.97); LPI 0.88 (0.89); DPI 0.55 (0.53).

Worker. Head elongate, rhomboid-like in full-face view, slightly wider anterad than posterad, posterior margin (defined by occipital carina) weakly concave to straight, lateral margin slightly convex, occipital carina welldefined; frontal carina extends posterad close to but not reaching ocular mid-length, median clypeal process strongly triangular, narrowing towards blunt apex. Eye prominent, convex, occupying close to one-quarter of lateral cephalic margin in cephalic full-face view. Cephalic dorsum smooth and shining with scattered piligerous punctae, clypeus with longitudinal striae that partially extend onto median process; cephalic ventral surface smooth and shining with scattered piligerous punctae. Scape smooth and shining, with abundant suberect hairs, longest hairs not longer than maximum scape width; scape extends beyond posterior cephalic margin by almost half its length; length of pedicel 2/3 that of third antennomere, and subequal to fourth antennomere length; length of third antennomere over 3x longer than its apical width; funicular segments cylindrical and densely covered with suberect hairs. Mandible elongate and subparallel, basal margin slightly convex, masticatory margin weakly concave and edentate, mandibular surface mostly smooth with scattered punctae and short rugulae basally; masticatory margin forms obtuse angle with basal margin. Palpal formula:4, 3.

Mesosoma with well-marked metanotal groove in lateral view that separates broadly convex promesotonal margin from mostly straight to slightly undulating dorsal propodeal margin, propodeal dorsum curves continuously to declivitous margin; declivitous margin weakly jagged; propodeum armed with low, broadly triangular teeth. Pronotum mostly smooth and shining with scattered punctae dorsally and scattered punctulae laterally, propleuron mostly smooth; mesonotum smooth with sparse punctae; propodeal dorsum mostly smooth, anteriorly with strip of transverse striae. Mesopleuron with transverse rugulae interspersed with colliculate areas; lateral surface of metapleuron and propodeum mostly smooth with scattered undulations and rugulae mostly concentrated posterad around metapleural gland and base of propodeal tooth. Propodeal declivity with transverse coarse striae.

Mesosternum in lateral view with anteromedian, longitudinal keel-like process that extends posterad to same distance as metanotal groove; keel with small, but distinct, posteriorly pointing denticle just anterad of posterior end of keel. Mesonotum in dorsal view rectangular, width 0.71–0.72 its length. Mesometapleural suture wellimpressed, scrobiculate; metapleuro-propodeal suture weakly defined as strip of short oblique parallel striae; anteroventral mesopleural carina well-developed, slightly expanded anterad; propodeal spiracle elongate, facing posterolaterally. Petiolar node in lateral view elongate and triangular, anterodorsal margin forms continuous convexity, highest point blunt, posterior margin mostly vertical, weakly convex. Anterior node margin width in dorsal view less than half that of posterior margin, lateral margin straight to weakly concave, posterior margin convex. Node smooth and shining with scattered short hairs, posterior face not sharply separated from lateral face. Gaster smooth and shining with scattered short, suberect hairs. Procoxa mostly smooth and shining in lateral view. Mesosoma with scattered to suberect and erect hairs; suberect to erect hairs present throughout head, coxa with decumbent hairs; mesotibia and metatibia with conspicuous pubescence. Protibial apex lacking apical seta, mesotibial external apex with single seta; metatibial external apex with 0/1 seta. Head, mesosoma, node, and most of gaster black; antenna, mandible, clypeus, legs, and apex of gaster brown.

Gyne and male. Unknown.

Etymology. The species name is derived from the Brazilian Portuguese noun for a person or thing originally from the state of Rio de Janeiro.

Discussion. Workers of L. carioca will key without ambiguity to couplet 30 in Lattke 2011, but then may cause some confusion as the propodeal dorsum does present some degree of punctures and rugulae. Nevertheless there are large areas of smooth and shining cuticle, enough that the irregular sculpturing does not dominate the dorsal propodeal surface, and thus it could be keyed to couplet 34, eventually arriving at couplet 37. A modification of the key in Lattke (2011) is provided below for identifying both L. carioca and L. academica . Besides the characters used in the key for separating these two new species the following morphological differences may also be observed. The pronotal dorsal margin in lateral view is evenly and broadly convex in L. carioca while in L. academica there is a distinct anterior margin separated by a blunt obtuse angle from the mostly horizontal dorsal margin. The metapleuro-propodeal suture in L. carioca is visible as a strip of shallow and short oblique parallel striae but this suture is not discernible in L. academica .

Itatiaia National Park protects part of the Itatiaia Plateau in the southern Mantiqueira mountains. The altitudes range from 1000 to 2000 m and most of the forests are classified as either Floresta Ombrófila Densa Alto-montana or Floresta Ombrófila Mista Alto-montana (IBGE, 2012) both with a canopy averaging 20 m high and belonging to an altitudinal subtropical climate (Cwb) in the Koeppen scheme. Temperatures during the year may vary from 3°C to 30°C, with occasional freezes some eight or so days in a year ( Meireles et al. 2014). Known from only two workers, we can only surmise that the species prefers the cooler elevations of the southern Atlantic Forest, ranging close to 2000 meters above sea level. This contrasts with the preference for lowland habitats that is more widespread for the genus ( Lattke 2011) and is of interest given the possible negative impact of climate change on mountain inhabiting biota, particularly in the tropics ( Lemes et al. 2014).

Figures

FIGURE2. Leptogenys carioca sp. nov. Holotype.A:Head,dorsal view.B:Body, lateral view.C:Body, dorsalview.All scale bars = 1 mm.