Rhopalothrix triumphalis Longino & Boudinot

Longino, John T. & Boudinot, Brendon E., 2013, New species of Central American Rhopalothrix Mayr, 1870 (Hymenoptera, Formicidae), Zootaxa 3616 (4), pp. 301-324 : 319-320

Rhopalothrix triumphalis Longino & Boudinot , sp. nov.

( Figs 1 A, 2B, 3F, 14, 16)

Type material. Holotype, worker: MEXICO, Chiapas: 2.8 km ESE Custepec, 15.72078 -92.93925 ± 50 m, 1800 m, 17 Jul 2007, mixed hardwood forest, ex sifted leaf litter (R.S. Anderson#2007-017) [CAS, unique specimen identifier CASENT0602067]. Paratypes (workers): same data as holotype but 18 Jul 2007, liquidambar forest (R.S. Anderson#2007-018) [ECOSCE, CASENT0601766]; 1.8 km SE Custepec, 15.72198 -92.95037 ± 50 m, 1530 m, mixed liquidambar forest (R.S. Anderson#2007-020) [MCZC, CASENT0601887]; 2 km SE Custepec, 15.72298 -92.94493 ± 50 m, 1650 m, ridgetop oak forest (R.S. Anderson#2007-021) [USNM, CASENT0601965]; 2.8 km SE Custepec, 15.72260 -92.93995 ± 50 m, 1840 m, oak forest (R.S. Anderson#2007-022) [UNAM, CASENT0603013].

Geographic range. Mexico (Chiapas).

Diagnosis. Anterior labral lobe bilobed, with lateral lobule longer than medial lobule; masticatory margin of mandible with two teeth; squamiform setae of first gastral tergite abundant, elongate, 4 × or 5 × longer than wide; HW 0.57–0.65.

Description. Worker. HW 0.57–0.65 (n=12); mandible with two teeth on masticatory margin, second tooth from base largest; subapical tooth with minute reclinate denticle at base; subapical tooth about twice as long as apical tooth; intercalary teeth prominent, one closest to apical tooth about half as long as apical tooth; labrum trapezoidal, anterior margin bilobed, lateral lobule triangular, longer than medial lobule, medial lobules rounded, flanking semicircular median notch; arcuate promesonotal groove and metanotal groove moderately impressed; propodeal tooth variable, obtuse, right angled, or acute, infradental lamella evenly and shallowly concave; squamiform setae abundant on first gastral tergite, uniformly covering entire tergite; gastral setae relatively long and thin, 4–5 × longer than wide, with elongate stem below widened apex.

Queen. HW 0.69; mandible and labrum similar to worker; face shape similar to worker but with less strongly developed grooves and ridges; compound eye longer than maximum width of scape; ocelli small, cuticle adjacent to ocelli marked with black pigment spots on evenly light brown background; shape of propodeal tooth, infradental lamella, petiole and postpetiole similar to worker; katepisternum and anepisternum large, convex, separated by broad U-shaped groove; layer of sparse, long, appressed pubescence covers mandible, face, scapes, legs, dorsal mesosoma and metasoma; abundant stiff erect setae on face, anterior edge of scape, side of head, dorsal mesosoma, dorsal gaster.

The male is unknown.

Biology. This species occurs in cloud forest habitats, from 1360–2140 m elevation. All specimens are from Winkler or Berlese samples of sifted leaf litter. It is sympatric with R. megisthmica on the slopes of Volcán Tacaná in Chiapas. At the type locality it was moderately abundant, occurring in 17 of 100 miniWinkler samples.

Comments. Rhopalothrix triumphalis , R. atitlanica , and R andersoni share a distinctive labrum shape with bilobed anterolateral margin, with the lateral lobule longer and more triangular than the medial lobule. The three form a geographic replacement series, with no known zones of sympatry. An isolated specimen from eastern Guatemala (Petén: 13 km NW Machaquilá, 16.44173 -89.53527 ± 26m, 390m, 28 May 2009, LLAMA#Wm-B- 06- 1-05, CASENT0614342) matches the size and morphology of R. triumphalis , differing only in the disposition of squamiform setae on the gaster. Instead of uniformly covering the first gastral tergite, they cover only the posterior 3/4. This specimen is left unidentified in this report, pending further understanding of the group.

Etymology. Referring to the type locality, El Triunfo Biosphere Reserve in the Sierra Madre de Chiapas.

Figures

FIGURE 1. Diagrammatic representation of Rhopalothrix mandibles. A. R. andersoni, R. isthmica, R. megisthmica (part), R. therion. B. R. atitlanica, R. megisthmica (part), R. triumphalis. C. R. stannardi. D. R. nubilosa, R. subspatulata. E. R. weberi. F. R. apertor.