Rhopalothrix nubilosa

This species occurs in cloud forest, at 1500 m elevation. It is known from one site on the Barva Transect in Costa Rica, where it occurred in 5 of 200 miniWinkler samples. (Longino and Boudinot 2013)

Identification
Longino and Boudinot (2013) - Sharing with Rhopalothrix subspatulata and Rhopalothrix weberi a characteristic labrum shape: anterior margin of labrum with two long, bluntly triangular lobes, sinus between them deep, length of anterolateral lobe longer than or about equal to distance from base of sinus to transverse carina at base of labrum; differing from both in larger size (HW = 0.57 versus < 0.50); differing from R. weberi in subapical tooth longer than apical tooth (about same length in R. weberi); differing from R. subspatulata in larger number of squamiform setae on first gastral tergite (about 12 versus about 6).

Distribution based on Regional Taxon Lists
Neotropical Region: Costa Rica.

Castes
Males are unknown.

Nomenclature

 *  nubilosa. Rhopalothrix nubilosa Longino & Boudinot, 2013: 314, figs. 1D, 2D, 3C, 10, 16 (w.) COSTA RICA.

This is a slightly more robust version of Rhopalothrix subspatulata. Among several other species of Rhopalothrix considered in this report, this degree of difference would be considered intraspecific. However, the sharply parapatric distribution on the Barva transect and the low variability among the many lowland collections of R. subspatulata suggest a separate montane species.

Worker
HW 0.57 (n=1); mandible with two closely-spaced short triangular teeth at base, a smaller tooth about mid-distance between basal teeth and base of subapical tooth, reclinate denticle at base of subapical tooth minute but present, apical tooth half the length of subapical tooth, intercalary teeth minute; labrum about as long as broad, with two long, bluntly triangular lobes, sinus between them deep, length of anterolateral lobe longer than or about equal to distance from base of sinus to transverse carina at base of labrum; erect setae on leading edge of scape moderately clavate, longest on basal bend, becoming shorter and thinner toward apex; arcuate promesonotal groove and metanotal groove moderately impressed; propodeal tooth right angled, infradental lamella evenly and shallowly concave; first gastral tergite with 6–8 squamiform setae on posterior margin, a similar number distributed between posterior border and midlength of tergite.

Type Material
Holotype, worker: Costa Rica, Heredia: 10 km NE Vara Blanca, 10.23696 -84.11983 ±125 m, 1500 m, 9 Mar 2005, montane wet forest, second growth, vegetation only about 4 m high, ex sifted leaf litter (ALAS#15/WF/02), unique specimen identifier CASENT0629594. Paratypes (workers): same data as holotype, CASENT0629593; same data but 10.23684 -84.11909 ± 50 m, mature forest (ALAS#15/WF/02/09) , INB0003666702; 10.23754 -84.12001 ±50 m (ALAS#15/WF/02/43) INBC, INB0003667096; 10.23771 -84.11998 ±50 m (ALAS#15/WF/02/47) INBC, INB0003667132; 10.23243 -84.11620 ± 50 m (ALAS#15/WF/04/15) INBC, INB0003668070; 10.23216 -84.11618 ±50 m (ALAS#15/WF/04/21) INBC, INB0003668120.

Etymology
Referring to the cloud forest habitat.

References based on Global Ant Biodiversity Informatics

 * Longino J. T. L., and M. G. Branstetter. 2018. The truncated bell: an enigmatic but pervasive elevational diversity pattern in Middle American ants. Ecography 41: 1-12.
 * Longino J. T., and B. E. Boudinot. 2013. New species of Central American Rhopalothrix Mayr, 1870 (Hymenoptera, Formicidae). Zootaxa 3616: 301-324.
 * Longino J. et al. ADMAC project. Accessed on March 24th 2017 at https://sites.google.com/site/admacsite/