Eurhopalothrix machaquila

This species is known from one locality in the lowland Petén region of Guatemala. Specimens were collected in patchy moist forest, all from Winkler samples of sifted leaf litter and rotten wood. The species occurred in 7% of quantitative miniWinkler samples. (Longino 2013)

Identification
Mandible with single tooth row; face with 14 or 16 specialized spatulate setae (anterior row 6 or 8, middle row 4, posterior row 4); ground pilosity of face spatulate, decumbent, weakly differentiated from specialized projecting setae, in discrete patches on posterolateral face, leaving median strip bare, anterior border of ground pilosity abrupt, at level of anterior row of specialized projecting setae, fading posterolaterally, becoming obsolete on vertex lobes; posteromedian vertex with shallow depression; promesonotum and first gastral tergite lacking specialized setae. Similar to Eurhopalothrix circumcapillum, Eurhopalothrix megalops, Eurhopalothrix ortizae, Eurhopalothrix oscillum, Eurhopalothrix schmidti, Eurhopalothrix semicapillum. (Longino 2013)

Distribution based on Regional Taxon Lists
Neotropical Region: Guatemala.

Nomenclature

 *  machaquila. Eurhopalothrix machaquila Longino, 2013: 127, figs. 14F, 23, 35 (w.) GUATEMALA.

Worker
HW 0.70, HL 0.64, SL 0.37, SLL 0.04, CI 109, SLI 11 (n=1). Labrum anterolateral gibbosities of basal portion developed as right-angled, ventrally-directed teeth, apical portion elongate, flexed dorsally, relatively narrow, distinctly bilobed at apex; apex with a fringe of short, non-capitate translucent setae; mandible triangular, dorsal surface convex, smooth and shining apically, grading to punctate basally, rounding into ventral surface; interior surface concave, smooth and shining; masticatory margin a single row of 11 flattened acute triangular teeth; scape with moderately developed basal lobe; scrobe deep, sharply delimited dorsally and ventrally, abutting deep antennal socket; surface of scrobe shallowly foveolate anteriorly, smooth and shiny posteriorly; eye small, about 5 ommatidia across greatest diameter; clypeus approximately planar, uniformly covered with small puncta; sides of head above eyes moderately angulate; surface of face with longitudinal median impression; entire surface of face punctate, puncta larger and sparser posteromedially, with smooth interspaces, becoming more confluent anteriorly and laterally; occipital carina indistinct; undersurface of head uniformly punctate; postgenal suture a well-developed longitudinal trough.

Promesonotal profile convex, with weakly differentiated anterior, dorsal, and posterior faces, meeting flat dorsal face of propodeum at obtuse angle; metanotal groove a narrow impressed groove; dorsal and posterior faces of propodeum distinct, meeting at obtuse angle, dorsal face shorter than posterior face; propodeal spine laminar, translucent, triangular, acute, ventral margin rounding into narrow infradental lamella that extends down posterior face to propodeal lobe; propodeal spiracle small, directed posteriorly in small concavity between base of propodeal spine and dorsum of metapleural gland bulla; pronotum and mesonotum uniformly punctate, puncta large with shiny interspaces similar in width to puncta diameter; anepisternum, katepisternum, side of propodeum, and dorsal face of propodeum with sparse, very small puncta, interspaces matte, much wider than width of puncta; posterior face of propodeum with sparse puncta dorsally, transverse rugulae medially, smooth and shiny ventrally.

Petiolar peduncle joins anterior face of petiolar node at rounded obtuse angle; anterior face of node meets sloping flat dorsal face at rounded acute angle; posterior face of node very short; ventral margin of petiole with short, acute, anteroventral tooth; postpetiole low and broad, with a broad longitudinal sulcus dorsally; first gastral sternite lacking anterior sagittal keel; dorsa of petiolar node and postpetiole punctate; first gastral tergite uniformly punctate, interspaces smooth and shining, subequal in width to width of puncta; first gastral sternite similarly punctate, but interspaces broader than puncta anteriorly.

Dorsal surface of scape with short, decumbent, spatulate setae; leading edge of scape with projecting clavate setae, short and strongly curved near apex of scape, basal 3 longer and more erect, longest seta on basal lobe; ground pilosity on clypeus obsolete; ground pilosity of face conspicuous, composed of short, flattened, appressed to decumbent setae, similar in shape and size to those on scape, distributed in two patches, delimited anteriorly at anterior row of projecting specialized setae, delimited medially to leave bare median furrow, gradually fading posterolaterally, obsolete on posterolateral vertex lobes; projecting specialized setae spatulate, about twice as long as wide, curved, about twice as large as ground pilosity (and thus not highly differentiated from it), full complement 16, with curved anterior row of 8, transverse median row of 4, and posterior row of 4 on vertex margin; ground pilosity obsolete on dorsal mesosoma and metasoma; dorsal mesosoma lacking specialized setae; legs with ground pilosity similar to that on face, dense on apices of femora, dorsal and anterior faces of mid and hind tibia, weaker on dorsal and posterior face of fore and midtibia, sparser to absent elsewhere; apex of foretibia with 1 larger spatulate seta, apices of mid and hind tibia with 2; basitarsus with 3–5 pairs suberect clavate setae, remaining tarsomeres each with pair of suberect clavate setae, tarsal setae smaller on foretarsus than on mid and hind tarsus; petiolar node, postpetiole, and first gastral tergite lacking specialized setae.

Color dark brown.

Queen
HW 0.70, HL 0.66, SL 0.39, SLL 0.03, CI 105, SLI 9 (n=1). Similar to worker in most respects; ocelli present; compound eye much larger than worker eye; anepisternum separated from katepisternum by U-shaped groove; metapleuron separated from propodeum by broad U-shaped groove; pronotum punctate, with smooth shiny interspaces slightly wider than width of puncta; anepisternum punctate posterodorsally, smooth and sublucid anteroventrally; katepisternum largely smooth and shining, with narrow rim of puncta posteriorly; side of propodeum sparsely punctate; mesoscutum and scutellum uniformly punctate; pronotum with 1 pair small, narrowly clavate setae; mesoscutum with 6 straight, erect, narrowly clavate setae; axilla with clavate seta; scutellum with 1 pair clavate setae; petiolar node, postpetiole, and first gastral tergite lacking specialized setae.

Type Material
Holotype worker: Guatemala, Petén: 13km NW Machaquilá, 16.44071 -89.53447, ±50 m, 390 m, 28 May 2009, tropical moist forest, ex sifted leaf litter (LLAMA Wa-B-06-2-08), unique specimen identifier CASENT0614288. Paratype workers, queen: same data as holotype but 16.44080 -89.53447, ±50 m, 390 m (LLAMA Wa-B-06-2-10), CASENT0614291; same data but 16.44178 -89.53460, ±50 m, 390 m (LLAMA Wa-B-06-2-34) CAS, CASENT0614311 (dealate queen); same data but 16.44181 -89.53469, ±50 m, 390 m (LLAMA Wa-B-06-2-36) , CASENT0614315; same data but 16.44227 -89.53534, ±36 m, 400 m (LLAMA Wm-B-06-1-06) , CASENT0614347.

Etymology
The name is in reference to the type locality. 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.