Leptanilloides atlantica, Silva & Feitosa & Brandão & Freitas, 2013

Silva, R. R., Feitosa, R. M., Brandão, C. R. F. & Freitas, A. V. L., 2013, The first Leptanilloides species (Hymenoptera: Formicidae: Leptanilloidinae) from eastern South America, Journal of Natural History (J. Nat. Hist.) 47 (31 - 32), pp. 2039-2047 : 2041-2045

Leptanilloides atlantica sp. nov. Silva, Brandão, Feitosa and Freitas

Figures 1A–D and 2A–F

Holotype worker

BRAZIL, SP, Santo André , Paranapiacaba , Reserva Biológica do Alto da Serra de Paranapiacaba, 23 ◦ 46 ′ 18 ′′ S, 46 ◦ 20 ′ 24 ′′ W, 800 m above sea level, Atlantic Forest, 12 January 2007; Uehara-Prado M. col.; Pitfall trap #K4; [ MZSP].

Paratype workers

Thirty-two point-mounted specimens with the same data as the holotype, [ MZSP (26), ZUEC (2), CASC (1), CPDC (1), MCZC (1), USNM (1)].

Worker measurements (holotype): HW 0.25, HL 0.34, SL 0.15, ML 0.41, PW 0.16, PL 0.11, PPL 0.11, FFeW 0.07, FFeL 0.19, HFeL 0.21, HTiL 0.23, AIVW 0.24, CI 74.51, SI 60.53.

Worker measurements and indices (15 measured): HW 0.24–0.25, HL 0.34–0.36, SL 0.14–0.16, ML 0.39–0.41, PW 0.15–0.17, PL 0.11–0.12, PPL 0.09–0.11, FFeW 0.07–0.08, FFeL 0.19–0.20, HFeL 0.20–0.21, HTiL 0.21–0.23, AIVW 0.23–0.25, CI 66.67–73.08, SI 57.89–66.67.

Diagnosis

Leptanilloides atlantica is similar to Leptanilloides biconstricta Mann from Bolivia, but can be easily distinguished from it by the uninterrupted mesopleura and metapleura reticulation, versus fine, superficial and interrupted in L. biconstricta . Leptanilloides atlantica also differs from L. biconstricta by the more densely foveolate head, with circa 20–30 foveolae covering a straight transverse line at head midlength, whereas there are only 10–20 in L. biconstricta . Additionally, L. atlantica can be distinguished from L. biconstricta by the petiole as long as the postpetiole (petiole longer than postpetiole in L. biconstricta ), comparatively smaller body size (best seen in head size and mesosoma length) and sternite on abdominal segment III anteriorly bulging (evenly rounded in L. biconstricta ). Leptanilloides atlantica is also similar to Leptanilloides femoralis Borowiec and Longino from Venezuela, with which it shares a relatively enlarged femur (FFeW 0.07–0.08 in L. atlantica , 0.08–0.09 in L. femoralis ), and the fine microreticulate sculpture on the mesopleuron, propodeum and petiole. It can be distinguished from L. femoralis by the presence also of a subpetiolar process with an acute anteriorly projecting tooth (absent in L. femoralis ). Leptanilloides atlantica can be differentiated from L. gracilis Borowiec and Longino based on the shallow anterior constrictions of abdominal segments IV–VI in L. atlantica , whereas they are deeply impressed in L. gracilis , and on the anteriorly bulging ventral margin of the abdominal segment III in L. atlantica , whereas in L. gracilis the ventral margin is evenly rounded ( Table 1).

Description

With the character states of Dorylomorphs, Leptanilloidinae and Leptanilloides ( Borowiec and Longino 2011) and with the body and appendages yellowish-brown covered by short, moderately abundant, subdecumbent to appressed hairs; somewhat longer hairs located on the anterior portion of the cephalic capsule. Dorsal surface of head with a longitudinal median line devoid of any sculpture. Head, mesosoma, petiole, postpetiole and gaster comparatively densely foveolate; head with circa 20–30 foveolae covering a straight transverse line at head midlength. Mesopleura and metapleura and propodeum entirely reticulate; petiole reticulate except on the dorsal face. Gaster smooth and shiny.

Head longer than broad. Lateral margins of head modestly convex and almost subparallel; occipital corners rounded; vertexal margin slightly convex. Clypeus with some setae projecting anteriorly. Mandibles short, with distinct basal and masticatory margins separated by a rounded angle; masticatory margin concave, bearing minute denticles; external margin of mandibles convex; dorsal surface with scattered piligerous punctures and short setae. Palp formula 2,2 (count in situ). Antennal scape short and clavate, about one-third of the total length of head, covered by evenly distributed piligerous punctures; first funicular joint incrassate, slightly longer than the second; apical segment about twice as long as the preceding segment.

Mesosoma subrectangular. Pronotum with the promesonotal suture conspicuous, complete and flexible. Metanotal groove not impressed. Posterior face of propodeum relatively short, meeting the dorsal face in a rounded and unarmed angle. Flange over the metapleural gland opening sharply pointed posteriorly. Tibiae enlarged apically; mid tibia with one simple and hind tibia with one pectinate spur.

Petiole slightly longer than broad; anterior face slightly concave in lateral view; in dorsal view, lateral margins straight; petiolar spiracle small and inconspicuous, set near the anterior rim of tergite subpetiolar process with an acute, anteriorly projecting tooth. Postpetiole relatively large, as long as the petiole, subquadrate in lateral view; anterior face concave medially and straight posteriorly, in dorsal view lateral margins diverging posterad; sternite spiracle set anteriorly on the tergite.

Abdominal segments IV, V and VI similar in length; abdominal segments III and IV broader than long in dorsal view.

Etymology

The type series was collected in a locality in the Atlantic Forest biome, and hence its name.

Comments

The sample includes 39 workers (six in alcohol) captured in a single pitfall trap set on the forest floor, at 800 m altitude. The collection point is a patch of secondary montane Atlantic Forest. The predominant climate in the region is humid, without a well-defined dry season; annual rainfall ranges from c.1860 to c. 4400 mm (see Uehara- Prado et al. 2009 for site details).

Figures

Figure 1. Worker of Leptanilloides atlantica sp. nov. from Santo André, Brazil. (A) Head in full-face view; (B) habitus; (C) body in dorsal view; (D) petiole and postpetiole in detail.

Figure 2. Scanning electron micrographs of Leptanilloides atlantica. (A) Detail of clypeal area and antennal insertions; (B) mouthparts in ventral view; (C) lateral view of mesopleuron, metapleuron and propodeum; (D) internal surface of posterior tibia; (E) detail of petiole and postpetiole in lateral view; (F) postpetiole and gaster in lateral view.