Lenomyrmex hoelldobleri, Rabeling, Christian, Sosa-Calvo, Jeffrey, O'Connell, Lauren A., Coloma, Luis A. & Fernandez, Fernando, 2016

Rabeling, Christian, Sosa-Calvo, Jeffrey, O'Connell, Lauren A., Coloma, Luis A. & Fernandez, Fernando, 2016, Lenomyrmexhoelldobleri: a new ant species discovered in the stomach of the dendrobatid poison frog, Oophagasylvatica (Funkhouser), ZooKeys 618, pp. 79-95 : 82-83

Taxon classification Animalia Hymenoptera Formicidae

Lenomyrmex hoelldobleri sp. n. Figure 1

Holotype worker.

ECUADOR: Esmeraldas; 4 Km SW of Alto Tambo, next to Reserve Otokiki; elevation 676 meters above sea level; GPS coordinates: 0.912306, -78.583528; 09.vii.2013; from the stomach content of a male specimen (frog voucher number: CJ1689; SVL = 36.7 mm) of the Little Devil poison frog, Oophaga sylvatica ; leg. L. A. O'Connell, E. E. Tapia, L. A. Coloma; unique ant specimen identifier: USNMENT01124322; deposited in USNM.

Measurements of holotype.

HL: 1.02; HW: 0.78; ML: 0.45; SL: 0.81; EL: 0.18; WL: 1.58; PL: 0.73; PW: 0.23; PPL: 0.46; PPW: 0.35; GL: 1.00; TL: 4.77; CI: 76; OI: 23; SI 79.

Description, holotype worker.

Mandibles elongate, triangular with masticatory margin crenulated, 3 times longer than basal margin, sclerotized blunt peg-like denticles barely visible at 80x magnification (Fig. 1A). Clypeus without carinae, apical margin mostly convex and with a median angle; posterior margin convex, barely projects backward between frontal carinae. Frontal lobes inconspicuous, little expanded laterally, only partially covering antennal condyles. Antennal fossae large, deep, 1.5x longer than broad. Antennal scrobes absent. In full-face view, head with a broadly convex posterior cephalic margin; in full-face view, maximum width, just behind eyes, slightly narrowing posterad. Compound eyes large, protruding, with 15 facets along maximum diameter. Mesosomal profile with pronotum, mesonotum, and propodeum differentiated. Metanotal impression clearly marked (Fig. 1C). Propodeum armed with 2 long, acute spines, clearly longer than distance between their bases (Figs 1B, C). In lateral view, inferior lobes of propodeum triangular. Femora claviform. Meso- and metatibiae lacking spurs. Tarsal claws simple, elongated. In lateral view, petiole long, fusiform, pedunculate; petiolar node well-defined; antero-ventral subpetiolar process directed forward, compressed in anterior-posterior direction, giving appearance of a spine in lateral view; anterolateral edges of process continue dorsally toward sides of petiolar peduncle. In lateral view, postpetiole dome-like, lacking a ventral process.

Mandibles smooth, slightly shining (Fig. 1A). Head, mesosoma, dorsum of petiolar node and postpetiole costate. The costae longitudinal in the head frons, concentric around eyes, predominantly transverse on pronotal dorsum, transverse on mesonotum, concentrically transverse on dorsum of propodeum (Fig. 1B), longitudinal on disc of petiole and postpetiole (Figs 1B, C). Lateral margins of mesosoma with longitudinal costae, coxae with transverse costae, discrete in meso- and meta-coxae. Petiolar peduncle with granulations. Postpetiole mostly shining, and dorsolaterally with fine longitudinal striae and granulations ventrolaterally. Gaster smooth, shining except for dense punctures on pygidium and hypopygium.

Clypeal apical margin with several short, erect hairs. Head frons, leading edge of antennal scape, pronotum, node of petiole, disc of postpetiole, and gaster with scattered erect hairs, most of them longer than maximum diameter of eye (Fig. 1A & B). Erect hairs on dorsum of petiole and legs as long as, or shorter than, maximum eye diameter. Hairs on antennal scape longer than maximum diameter of antennal scape. Funicular antennal segment with numerous short decumbent hairs. Otherwise body devoid of hairs. Body black; legs and coxae lighter; antennal club, mandibles, and gastric apex yellowish-brown.

Distribution and ecology.

The single known specimen of Lenomyrmex hoelldobleri was recovered from a stomach content sample of the dendrobatid poison frog, Oophaga sylvatica . The habitat where the poison frog Oophaga sylvatica was collected was a secondary habitat with forest fragments and pastureland. The region encompasses remnant Evergreen Foothill Forests of the Western Cordillera ( Ministerio del Ambiente del Ecuador 2012). This area is located in the Chocó Ecoregion, one of the most biologically diverse areas in the world with exceptionally high levels of endemism. The Chocó is considered one of the biodiversity hotspots for conservation purposes ( Mittermeier et al. 1998, Myers et al. 2000) and one of the most threatened areas in the world ( Brooks et al. 2002). The coastal northwest region of Ecuador, where the Alto Tambo area is found, is part of the wettest ecosystem known in Ecuador, with rainfalls ranging from 2000 up to 4000 mm annually ( Ministerio del Ambiente del Ecuador 2012). Temperatures range from an annual average of 20 to 25° C ( Ministerio del Ambiente del Ecuador 2012). The Foothill Forests are characterized by the dominance of tree species that can exceed 30 m in height. Trees are covered by orchids, bromeliads, ferns, and aroids. These forests have a dense herbaceous undergrowth layer dominated by Marantaceae , Araceae , and Polypodiopsida ( Cerón et al. 1999). Two species of Lenomyrmex ( Lenomyrmex foveolatus , Lenomyrmex hoelldobleri ) occur in sympatry in the Alto Tambo area (Fig. 4).

Queen and male.

Unknown.

Etymology.

This species is named in honor of our colleague and friend Bert Hölldobler on the occasion of his 80th birthday. Because of Bert's passion for ants, his pioneering and high-caliber contributions to entomology and behavioral ecology, as well as his dedication to mentoring the next generation of myrmecologists, myrmecology has become its own discipline in entomology, and continues to attract enthusiastic students who share Bert's love for ants.

Comments.

Lenomyrmex hoelldobleri can be distinguished from all other Lenomyrmex species by the following combination of character states: (i) petiolar node conspicuous, well-defined; (ii) a well-defined metanotal suture; (iii) conspicuous costae on its body; (iv) long erect hairs on the scape, and (v) size, being larger than all known species. Lenomyrmex costatus is morphologically most similar to Lenomyrmex hoelldobleri and both share the integumental sculpturing and the presence of long setae on the antennal scapes. However, Lenomyrmex hoelldobleri can be clearly distinguished from Lenomyrmex costatus by its well-defined petiolar node, the presence of the metanotal suture, its larger size, by having concentrically transverse striae on dorsum of propodeum (longitudinal in Lenomyrmex costatus ), and the distinctly darker coloration (compare Figs 1, 2). To differentially diagnose Lenomyrmex hoelldobleri and Lenomyrmex costatus , we examined the holotype of Lenomyrmex costatus (Fig. 2). The specimen is deposited at Museum of Comparative Zoology at Harvard University. The specimen information is as follows: Panama; Bocas del Toro; Fortuna to Chiriqui Grande rd.; elevation 1050 meters above sea level; GPS coordinates: 8°47'N, 82°12'W; 14.vii.1987; leg. D. M. Olson (DMO523); unique ant species identifier: MCZ-ENT00036069.