Eurhopalothrix vulcan

Known from a single worker collected from cloud-forest leaf litter.

Identification
Mandible with double tooth row; face with 5 pairs erect setae, arranged as medial rectangle of 2 pairs flanked anterolaterally by 2 pairs; promesonotum with 3 pairs specialized erect setae; ground pilosity on face flattened, conspicuous. Similar to Eurhopalothrix hunhau, Eurhopalothrix sepultura. This species shares a distinctive facial seta pattern and peculiarly flattened labral setae with E. sepultura, from the geographically close Sierra Madre de Chiapas. The two are likely closely related.(Longino 2013)

Key to New World Eurhopalothrix

Distribution based on Regional Taxon Lists
Neotropical Region: Guatemala.

Castes
Known only from the worker caste.

Nomenclature

 *  vulcan. Eurhopalothrix vulcan Longino, 2013: 143, figs. 32, 35 (w.) GUATEMALA.

Worker
HW 0.71, HL 0.70, SL 0.41, SLL 0.08, CI 101, SLI 19 (n=1). Mandible not spread on unique holotype, but appears similar to labrum of E. sepultura, including the uniquely capitate and flattened fringing setae on the labral lobes; mandible triangular, assumed similar to E. sepultura in most respects (presence of double tooth row visible in ventral view of holotype); scape with strongly developed basal lobe; scrobe deep, sharply delimited dorsally and ventrally, abutting deep antennal socket; surface of scrobe foveolate; eye with about 5 ommatidia across greatest diameter; clypeus approximately planar, roughened, dull; juncture of clypeus and frons deeply impressed, clypeal plane somewhat elevated above anterior frons; sides of head above eyes rounded; surface of face convex, shallowly reticulate rugose, dull, with weakly developed medial longitudinal carina on anterior frons; occipital carina a short carina dorsally, obsolete laterally.

Profile of promesonotum and dorsal face of propodeum forming more or less continuous convexity; metanotal groove impressed; anterior border of dorsal face of propodeum delimited with small, raised rim; dorsal and posterior faces of propodeum distinct, meeting at obtuse angle, dorsal face shorter than posterior face; propodeal spine laminar, translucent, acute, ventral margin curving into narrow infradental lamella that extends down posterior face to propodeal lobe; propodeal spiracle distinct, directed posteriorly; promesonotum punctate anteriorly, grading to irregularly rugulose posteriorly, a small median rugule forms a short elevated longitudinal keel on posterior mesonotum between posteriormost pair of spatulate setae; lateral pronotum, dorsal and posterior face of propodeum, anepisternum, katepisternum, and side of propodeum punctate, bulla of metapleural gland smooth, matte; lacking transverse carinulae between propodeal spines.

Petiolar peduncle joins anterior face of petiolar node at obtuse angle; petiolar node subquadrate, anterior face meets flat-topped dorsal face at rounded right angle, sloping dorsal face rounds into short posterior face; ventral margin of petiole with short, acute anteroventral tooth; postpetiole low and broad, with a shallow longitudinal sulcus dorsally; first gastral sternite lacking anterior sagittal keel; petiole, postpetiole, first gastral tergite covered with dense, small, puncta, interspaces less than width of puncta; first gastral sternite similar, but puncta and interspaces larger.

Dorsal surface of scape with abundant flattened, appressed setae on basal lobe and along leading edge, obsolete elsewhere; leading edge of scape with projecting clavate setae, shortest near apex, gradually lengthening toward base; ground pilosity on face of flattened, appressed, conspicuous setae, uniformly distributed on posterolateral vertex lobes, sides of face and onto frontal lobes, obsolete on anterior frons, thinner and shorter but still conspicuous and evenly distributed on clypeus; projecting specialized setae strongly spatulate to pompon-like, 2x longer than wide, full complement 10, a medial rectangle of 2 pairs, an additional 3 between medial rectangle and compound eye (together anterior 8 forming uniform arch across face); ground pilosity thin, sparse to obsolete on dorsal mesosoma, petiole, postpetiole, and first gastral tergite; 5 large pompon-like setae on promesonotum (full complement presumably 6); legs with moderately abundant, flattened, appressed setae on posterior face of foretibia, anterior face of midtibia, anterior face of hindtibia, somewhat sparser on other surfaces; apices of tibiae with 1 larger spatulate seta; basitarsus and remaining tarsomeres with abundant, spatulate setae; two spatulate setae on hind margin of dorsal face of petiolar node; row of 4 spatulate setae on hind margin of postpetiole, inner pair smaller than outer pair; specialized setae of first gastral tergite spatulate, full complement 4 pairs in two longitudinal rows, posteriormost row flanked by an additional pair (4 setae along posterior border of tergite).

Color red brown.



Type Material
Holotype worker: Guatemala, Suchitepéquez: 4km S Volcán Atitlán, 14.54856 -91.19097, ± 50 m, 1625 m, 15 Jun 2009, cloud forest, ex sifted leaf litter (LLAMA Wa-B-09-1-09), CASENT0612902.

Etymology
Named for the Roman god of volcanic fire. It is a noun in apposition and thus invariant.

References based on Global Ant Biodiversity Informatics

 * Longino J. T. 2013. A review of the Central American and Caribbean species of the ant genus Eurhopalothrix Brown and Kempf, 1961 (Hymenoptera, Formicidae), with a key to New World species. Zootaxa 3693(2): 101-151.
 * 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.