Megalomyrmex longinoi

This species is known from three independent collections; two were Panamanian leaf litter samples in the secondary forest of Gigante Peninsula, part of the Barro Colorado Natural Monument. One of these samples contained two workers, while the other contained numerous workers, larvae, pupae, and four dealate queens and was likely a polygynous colony nesting in the leaf litter. The third sample was collected off of Pipeline Road in the Soberanía National Park in Panama and was a colony (two dealate queens, >70 workers, and brood) nesting in a log. (Boudinot et al. 2013)

Identification
Boudinot et al. (2013) - Worker unique among the described Megalomyrmex for the presence of rugulose or costate sculpture covering the head, mesosoma, petiole and postpetiole. Identification supported by the following combination of characters: (1) mandible subfalcate; (2) basal mandibular teeth variable, but with basal or subbasal tooth largest; (3) eyes relatively close to lateral clypeal margin (OMI < 60); (4) scapes relatively long (SI > 115).Queen uniquely identified by the sculpturation described for the worker, alate.

This species is very similar to Megalomyrmex cuatiara, but is unique within the genus for the rough sculpturation of the entire head and mesosoma. In addition to sculpturation, the following characters distinguish M. longinoi from M. cuatiara: (1) medial margin of mandibular base distinctly dentate (vs. indistinctly dentate); (2) setae on scape appressed to decumbent (vs. subdecumbent to suberect); (3) Metanotum strongly impressed (vs. shallowly to not impressed); (4) posterior face of promesonotum steep, almost vertical, distinct from promesonotal dorsum (vs. promesonotum curving evenly and shallowly through metanotum); (5) dorsal face of propodeum very short (vs. dorsal face of propodeum long); (6) red-orange (vs. yellow).

Key to Central American Megalomyrmex workers

Distribution
Panama; sea-level to 150 m elevation.

Distribution based on Regional Taxon Lists
Neotropical Region: Panama.

Nomenclature

 *  longinoi. Megalomyrmex longinoi Boudinot, Sumnicht & Adams, 2013: 39, figs. 21, 23, 123–126, 239 (w.q.) PANAMA.

Worker
(holotype): HW 0.54, HL 0.63, SL 0.77, OMD 0.10, EL 0.19, ML 0.80, CI 86, SI 122, EI 36, OMI 52. (n=10): HW 0.51–0.54, HL 0.57–0.63, SL 0.71–0.78, OMD 0.09–0.10, EL 0.17–0.20, ML 0.74–0.80, CI 85–89, SI 120–125, EI 33–37, OMI 46–56.

Head Palpal formula 3,2. Mandible subfalcate, with 7–9 teeth: apical and subapical always largest; second or third tooth from base also large; remaining teeth small and of variable size, and basal tooth present or absent. Dorsal surface of mandible smooth and shining. Basal half of mandibular basal margin with minute denticle. Clypeus with transverse rugae which branch posteriorly at the median portion. Sculpture of head dorsum finely foveate with thin, extensive rugae spanning the vertex, surrounding the eyes, and extending from the frontal carinae leaving a shining patch in the center of the frons. Compound eyes glabrous. Occipital carina thin and barely visible in full-face view; angled medially on postgenal bridge and fading less than one fourth distance to hypostomal margin. Mesosoma Mesosoma with numerous rugulae and carinulae; pronotum with transverse rugulae which curve posterolaterally along the lateral faces; rugulae on mesonotum more longitudinal. Mesopleuron and lateral portions of propodeum foveate. Posterodorsal face of propodeum with transverse carinulae throughout, becoming more rugulose as they extend onto lateral faces. Foraminal carina entire. Meso- and metabasitarsi not anteroposteriorly compressed. Metasoma Anterior faces of petiole and postpetiole smooth and shining; posterodorsal margin of petiole with transverse arcing costulae. Ventral margin of petiole gently convex in profile; ventral surface with numerous transverse carinulae. Postpetiolar sternum with a weak anterior convexity. Lancets of sting apparatus slightly longer than sting shaft, broadening apically, subspatulate; sting shaft very slightly broadened after midlength, but parallel to pointed apex. Setation Head with sparse, long subdecumbent to suberect setae; promesonotal dorsum with four consecutive pairs of conspicuous suberect setae; similar pair on apex of propodeum pointing anteriorly; petiolar node with three pairs of setae along a single transverse axis, two long pairs towards the apex, and a shorter pair towards the base; gaster smooth and shining with sparse, long subdecumbent setae. General body and appendage color pale to deep golden yellow.

Queen
(n=5): HW 0.56–0.62, HL 0.64–0.68, SL 0.76–0.77, OMD 0.08–0.09, EL 0.24–0.25, ML 0.93–1.00, CI 90–92, SI 113–119, EI 40–42, OMI 32–37.

General shape, sculpture, dentition, and pilosity similar to worker; mesoscutum with two anterolateral shining patches devoid of sculpture.

Type Material
Holotype worker PANAMA, Panamá: Canal Zone, Gigante Peninsula, 9.11131°N 79.84818°W, ±150 m, 110 m, seasonally wet secondary forest ex sifted leaf litter, 1–15 June 2011 (T.P. Sumnicht#TPS LIA-4RDN1) CASENT0619091,. Paratype workers: (9) same data as holotype (CASENT0619092, ; CASENT0619093, ; CASENT0619094, ; CASENT0619095, ; CASENT0619096, ; CASENT0619097, ; CASENT0619098, ; CASENT0619099, ; CASENT0629782, ). Paratype queens: (7) same data as holotype (CASENT0619100, CAS; CASENT0619101, INBC; CASENT0619105, MCZ; CASENT0619102, MCSN; CASENT0619103, MZSP; CASENT0619104, USNM).

Etymology
Named after Dr. John T. Longino for his invaluable advising and insight.