Bariamyrma hispidula

This is the only known species of Bariamyrma. This species, and genus, is only know from the queen caste. Collections consist of a few widely scattered records of single queens. Lattke suggests the collection of the holotype from a flight intercept trap on the ground means this is likely a ground nesting species and not a canopy dwelling ant. Subsequent collections (shaded lawn, flight intercept and Malaise) are consistent with this suggestion.

Identification
Lattke's (1990) discussion of placement of the genus in relation to other Mymricinae is helpful for making determinations:

The placement of this genus of apparently lower Myrmicinae into established tribes or genus groups at this moment is not clear. On account of its apomorphies it is obviously not a member of the Myrmica nor Tetramorium genera groups. If we consider the Pheidologeton group and the characters listed by Ettershank (1966: 115) as well as those pointed out by Bolton (1987: 265) there seems to be no affinity. The lack of a clearly defined antennal club and presence of well developed frontal carinae in Bariamyrma plead against such a grouping. The only other universal characters within pheidologetines are the lack of a prominent median clypeal seta and a closed radial cell of the fore wing, but both are plesiomorphic states and of limited phylogenetic value. To place it in the Pheidolini or Myrmecini, polyphyletic assemblages of genera, would be of no heuristic value.

The specimen does share a number of characters with Lordomyrma such as the mandibular structure, convex clypeus, frontal lobes, frontal carinae, antennae, and propodeal spiracles set well forward from the margin of the declivity. Yet in Lordomyrma the clypeus is clearly bicarinate, and distinct, albeit flat, antennal scrobes are formed. In this genus the petiolar peduncle tends to be shorter, the humeral angles somewhat sharper, tibial spurs are wanting, the sting presents no flange and the propodeal spiracle is below the base of the propodeal spine. Wheeler (1919: 105) illustrates the forewing of a male Lordomyrma and it is quite similar to Bariamyrma except for the anal vein, which does not extend beyond cu-a. Wheeler also notes the presence of hairy wings. A survey of the other genera related to Lordomyrma, such as Cyphoidris Weber, Lachnomyrmex Wheeler, Dacetinops Brown & Wilson, and Indomyrma Brown reveals distinct antennal scrobes and clubs, the lack of apical spurs on the meso- and metatibiae, and a raised, usually bicarinate, median clypeus. The sting in Lachnomyrmex tends to be flattened, and in Cyphoidris terminates in a narrow spatulate appendage. Lachnomyrmex has its propodeal spiracles set well back from the declivitous face margin, but Cyphoidris and Dacetinops have them positioned quite posterad. Accepting Bariamyrma as a member of this assortment of genera, and even though it has several apomorphies in relation to them, such as the reduced palpal segmentation and form of the sting, on the whole it seems that Bariamyrma is a somewhat primitive member of the group.

Distribution
Known from Costa Rica, Paraguay and Venezuela.

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

Castes
Known only from the queen caste.

Nomenclature

 *  hispidula. Bariamyrma hispidula Lattke, 1990a: 174, figs. 1-4 (q.) VENEZUELA.

Queen
Holotype — Dimensions: HL 1.34, HW (excluding eyes) 1.17, ED 0.33, ML (straight line distance along external margin from insertion to anteriormost margin) 0.73, SL 0.95, WL 2.03 mm, CI 0.87, SI 0.81, MI 0.63.

Head in full face view with posterior margin broadly convex, sides more or less parallel. Clypeus with transverse rugae. Eyes large and prominent, situated at cephalic midlength, 3 well developed ocelli present at vertex. Dorsolateral mandibular surface rugulose, but smooth and shining about the chewing and basal margins. Dorsal cephalic sculpture between frontal carinae longitudinally porcate. Frontal lobes anteriorly thin and lamellar, partially raised and leaving the basal condyles partially exposed in frontal view. Basal antennal sclerite partially covering part of the basal condyle, condylar constriction sharp, forming an obtuse angle with an oblique basal flat surface of the scape. Antennal fossae deep, laterally bordered by more or less parallel rugulae that become more irregular between the eye and frontal carina and posterad. Flexor surface of scape with a broad sulcus, scape slightly bent basally, expanding apicad. Scape with longitudinal costulae; funicular segments colliculate. Cephalic ventrum with a median carina, and medially smooth and shining.

Pronotal collar with imbricate microsculpture. Frontal pronotal surface transverse porcate, anterolaterally with an excavate area of smooth sculpture behind the lower occipital corners of the head. Pronotum with a lateromedian depression and with a convex posterior lobe; sculpture porcate-rugose. Humeri bluntly angulate in dorsal view. Mesonotum longitudinally rugose. Anepisternum with transverse rugae, divided from katepisernum by a broad and deep sulcus. Katepisternum with transverse rugae but more sharply defined than in the anepisternum, with broader and shallower areas between them. Carinae on metapleuron and lateral propodeal face as in anepisternum, slightly more effaced. Propodeal spiracle large and rounded, facing obliquely caudad. Suture before scutellum broad and with two median concave depressions. Scutellum roughly rugose, with an anterior shelf and a slight median depression deviding the sclerite into two low lateral bulges. Declivitous propodeal face transversely porcate above teeth, smooth and shining between and below them. Inferolateral propodeal margin with very broad smooth and shining areas between sparse carinae; opening of metapleural gland contained in a thin-walled cup like structure. Low rugosities on petiole and postpetiole.

First gastric segment larger than other segments, mostly smooth and shining except for a short series of longitudinal carinae next to the postpetiolar junction. Gaster in lateral view ventrally convex and dorsally broadly convex. Tibiae and femora with longitudinal low rugosity; claws simple. Most of body plus extremities covered with abundant stiff, erect to suberect, bristle-like hairs. Decumbent hairs on mandibles, scapes, funiculus. Abundant decumbent pilosity on pro not urn and legs; also on anterior and anterolateral pro coxal faces, mesocoxae and anterior mesocoxal face. Sparse decumbent pilosity on gaster. Body blackish brown, legs slightly lighter, wings brown.

Type Material
Holotype Queen, Venezuela: Amazonas, Cerro de la Neblina Basecamp, 0°50'N 66°10'W, 140 m, flight intercept pan trap in rainforest, 21-28.11.1985, P. J. Spangler.

Etymology
The generic name Baria is the name of a river next to the Cerro Neblina expedition basecamp. The species name is derived from the Latin diminutive for bristly, hispidula.