Kalathomyrmex emeryi

This enigmatic species, the only member of its genus, creates soil nests that are able to withstand long periods of inundation.

Identification
As the only member of its genus, the following means of separating the genus from other ant genera is sufficient for identifying this species:

The here described monotypic genus Kalathomyrmex; with Kalathomyrmex emeryi as the type species, presents the following exclusive set of characters: subquadrate head shape; reduced arched frontal lobes; subtriangular mandibles with five teeth; triangular clypeus with latero-posterior margins strongly produced forwards over the lateral wings of the clypeus as rounded ridges, resulting in two large circular areas where the antennal scapes articulate, junction of antennal insertion area and clypeus with long setae, forming a psammophore (apparently non-homologous with the Paramycetophylax psammophore and a putative synapomorphy for Kalathomyrmex); lack of a median clypeal seta (otherwise universal in Attini); noticeably slender body; and median dorsal conical protuberance in the posterior area of the mesonotum. Also, in contrast to the species of Mycetophylax as accepted here, the species of Paramycetophylax and Kalathomyrmex females share a morphological character state of the postpetiole with a large posterior impression, almost dividing it into two lobes. (Klingenberg and Brandao 2009)

Distribution
Kalathomyrmex emeryi is distributed all over cis-Andean South American.

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Bolivia, Brazil, Colombia, Paraguay, Uruguay, Venezuela.

Biology
Information on the biology of this species is scant. As mentioned above, Bucher (1974) described the nest architecture of Paramycetophylax bruchi and K. emeryi; both species inhabit sandy soil and prefer places devoid of vegetation. We confirmed this observation for K. emeryi, as we found this species nesting at the beaches of the Rio Negro (AM), Brazil. The nests are quite common at the sandy beaches of the river and can be easily located. In the Amazonian rainy season, the nests become covered by water for months. This observation has been confirmed by Dr. M. Verhaagh in Peru (pers. comm.), who found a K. emeryi nest nearby a river bank covered by high water for several days; when the river returned to its normal water level, the ants reopened the entrance and came out of the nest. According to Bucher (1974), the fungus chambers are located from 60 to 100 cm deep, but can be found deeper due to temperature changes during the year. For the fungus substrate, the species forages for feces of other insects, mainly of Lepidoptera. The ants showed their highest activity during the night. However, we observed K. emeryi in frantic activity during the day in several instances, even with relatively high temperatures and under full sun exposure. (Klingenberg & Brandão 2009)

Nomenclature

 *  emeryi. Myrmicocrypta emeryi Forel, 1907f: 144 (w.) COLOMBIA. Forel, 1912e: 189 (q.m.). Combination in Cyphomyrmex (Mycetophylax): Emery, 1913b: 251; in Myrmicocrypta (Mycetophylax): Santschi, 1916e: 383; in Mycetophylax: Santschi, 1925e: 163. Senior synonym of hummelincki: Weber, 1958d: 263; of arenicola, argentina, bolivari, fortis, gallardoi, glaber, hubrichi, weiseri: Klingenberg & Brandão, 2009: 22.
 * arenicola. Myrmicocrypta emeryi var. arenicola Forel, 1912e: 189 (w.q.) ARGENTINA. Combination in Cyphomyrmex (Mycetophylax): Emery, 1924d: 343; in Myrmicocrypta (Mycetophylax): Santschi, 1922b: 355; in Mycetophylax: Kempf, 1972a: 146. Junior synonym of emeryi: Klingenberg & Brandão, 2009: 22.
 * fortis. Myrmicocrypta emeryi var. fortis Forel, 1912e: 189 (w.) ARGENTINA. Combination in M. (Mycetophylax): Santschi, 1922b: 355; in Cyphomyrmex (Mycetophylax): Emery, 1924d: 343; in Mycetophylax: Kempf, 1972a: 146. Junior synonym of emeryi: Klingenberg & Brandão, 2009: 22.
 * argentina. Myrmicocrypta (Mycetophylax) emeryi var. argentina Santschi, 1916e: 383 (w.) ARGENTINA. Combination in Cyphomyrmex (Mycetophylax): Emery, 1924d: 343; in Mycetophylax: Kempf, 1972a: 146. Junior synonym of emeryi: Klingenberg & Brandão, 2009: 22.
 * gallardoi. Myrmicocrypta (Mycetophylax) emeryi st. gallardoi Santschi, 1922b: 354 (w.) ARGENTINA. Combination in Mycetophylax: Kempf, 1972a: 146. Junior synonym of emeryi: Klingenberg & Brandão, 2009: 22.
 * hubrichi. Mycetophylax emeryi st. hubrichi Santschi, 1925e: 163, fig. 6 (w.) ARGENTINA. Junior synonym of emeryi: Klingenberg & Brandão, 2009: 23.
 * weiseri. Mycetophylax emeryi st. weiseri Santschi, 1929d: 303 (w.) BRAZIL. Junior synonym of emeryi: Klingenberg & Brandão, 2009: 23.
 * bolivari. Mycetophylax bolivari Weber, 1948b: 84 (w.) VENEZUELA. Subspecies of emeryi: Weber, 1958d: 263. Junior synonym of emeryi: Klingenberg & Brandão, 2009: 22.
 * glaber. Mycetophylax glaber Weber, 1948b: 85 (w.) BOLIVIA. Junior synonym of emeryi: Klingenberg & Brandão, 2009: 23.
 * hummelincki. Mycetophylax hummelincki Weber, 1948b: 84 (w.) VENEZUELA. Junior synonym of emeryi: Weber, 1958d: 263.

Description
Klingenberg & Brandão, 2009:

Worker
Range of measurements (in mm) and indices of examined specimens (N = 76): IOD 0.49-0.83; HL 0.54-0.83; CI 85-106; SL 0.48-0.8; SI 84-112; ML 0.23-0.48; MI 34-77; WL 0.70-1.26; PrW 0.26-0.60; PL 0.16-0.30; PPL 0.19-0.35; GL 0.57-0.92; FL 0.52-0.98; TL 2.42-4.03.

Color in general yellowish to reddish-brown, some specimens may be darker. Apex of funiculus, clypeus, and masticatory border of mandibles, head vertex, postpetiole, gaster and femora brownish. Mandibles and tarsi yellowish; rest of the body light reddish brown. Under optical scope, body sculpture densely punctuated with exception of lateral parts of pronotum, where the sculpture is more superficial. Mandible disc shiny with piliferous punctuations. Mesosoma covered by a fine layer of “dirt”, visible only in SEM images in a way that the sculpture of the integument is “reprinted” in the dirt-layer. Whole body covered by shiny whitish to golden appressed hairs. Long, flexuous hairs covering the mandibles and gular face.

Head shape quadrate (see CI). Mandibles with five teeth, apical tooth larger, followed by smaller second and third teeth. After the diastema a small fourth tooth followed by a small denticule. Anterior margin of clypeus gently concave. In lateral view, clypeus triangular. In frontal view latero-posterior margin of clypeus strongly produced forwards over the lateral wings of the clypeus, as rounded trenchant ridges, resulting in two large flat circular areas where the antennal scapes articulate. Median portion of clypeus attains posteriorly the posterior level of the antennal insertions in a generally straight sometimes rounded suture, followed by a small impressed triangular frontal area. A shallowly impressed median line running from the frontal area to the vertex. Frontal lobes reduced, barely covering the antennal insertions, their maximum expansion less than a fourth of a longitudinal median head axis and the lateral margins of head, ending posteriorly at the level of the posterior margin of compound eyes. Lateral carinae bordering the internal margins of the compound eyes, fading out a little after their posterior margins. Compound eyes set slightly before the middle of the head, at maximum width with ten ommatidia and at maximum length with 14 ommatidia. Vertexal margin straight, but occasionally with a median impression. Antennae with flattened scapes, surpassing the posterolateral corners of the head when laid back over the head capsule. First funicular segment as long as the second and the third together. Apical end of funiculus with a three segmented club, only a little wider than the other funicular segments. Ventral face of head flat.

Mesosoma. Pronotum without tubercles or distinct protuberances, lateral pronotal margins rounded, without spines or angles. Occasionally the pronotum bearing a blunt obliquely directed spine (specimens from Paraguay and Argentina). Dorsal face of mesonotum evenly rounded, in side view, followed by a small depression and a conical low protuberance. Anepisternum clearly divided from the mesonotum by a carina. In lateral view, basal face of propodeum slightly convex anteriorly, meeting the concave declivous face and about one half shorter than basal face. Propodeal spiracle opening in an angle of 45° in relation to the main body axis. Propodeum with a pair of divergent, short, blunt obtuse angles, directed obliquely upwards. In dorsal view, petiole straight, wider at three fourths of its length, with a vestigially developed ventral process. Postpetiole, in dorsal view, subtriangular, with a large impression at posterior margin, forming two distinct lobes, heart-shaped and dorsoventrally flattened.

Gaster smooth, without protuberances or carinae.

Queen
Range of measurements (in mm) and indices of examined specimens (N = 10): IOD 0.54-0.64; HL 0.56-0.63; CI 90-107; SL 0.5-0.56; SI 83-100; ML 0.26-0.34; MI 43-61; WL 0.94-1.02; PL 0.16-0.24; PPL 0.2-0.24; GL 0.84-0.98; TL 3.01-3.36.

Color, pilosity and main morphological traits of head, propodeal spiracle, petiole, postpetiole and gaster similar as in the conspecific workers. Mandible with five teeth, apical tooth bigger than all the others, followed by smaller second and third triangular teeth; fourth tooth triangular and smaller than the second and third, followed by a small denticle. Compound eyes with 15 ommatidia at maximum width and 17 ommatidia at maximum length. Posterior portion of head with three ocelli, the median superficially impressed at frons. The apical funicular segment as long as the three anterior together.

Mesosoma in lateral view with dorsally flattened scutum, in lateral view, dorsum of scutum starts at the anterior third of the pronotum. In dorsal view anterior margin and posterior margin round, the last ending in a carina. Parapsidial lines shallowly impressed. Prescutum reduced, represented only by triangular axillae; scutum-scutellar sulcus deeply impressed. Scutellum subquadrate, anterior third wider than posterior portion, posteriorly rounded. Metanotum reduced, appearing only as small, flattened disc in dorsal view. Katepisternum rectangular; anepisternum only half the size of the katepisternum, subquadrate, and both separated by a distinct groove, ending posteriorly in a carina. Propodeum with a small blunt obliquely upwards directed spine.

Male
Range of measurements (in mm) and indices of examined specimens (N = 10): IOD 0.21-0.34; HL 0.24-0.34; CI 88-100; SL 0.32-0.42; SI 110-152; ML 0.13-0.18; MI 38-53; WL 0.76-0.92; PL 0.10-0.18; PPL 0.12-0.20; GL 0.68-0.82; TL 2.31-2.58.

Color brownish to dark brown. Anterior half of mandibles, funiculus, labrum, legs and apex of gaster light yellow. Under optical scope, body densely punctuated, with exception of shiny gaster, where sculpture is more superficial. Whole body covered by golden, shiny, appressed hairs. Head shape quadrate (see CI). Mandibles with three multidenticulate teeth, apical tooth longer than the others, followed by a smaller second triangular tooth and a denticle, better visible with SEM images. Anterior margin of clypeus straight. Clypeus with a psammophore composed by four setae arising from the meeting of the clypeus and the anteclypeus. Psammophore hairs fine and stiff as long as the length of the two apical segments of funiculus, reaching the apex of the mandibles. In frontal view, clypeus bulging, its posterior margin not forming a trenchant ridge. Frontal lobes reduced, covering only half of the antennal insertions, ending posteriorly at the level of the anterior margin of compound eyes. Lateral carinae marginate the compound eyes anteriorly. Compound eyes set at anterior part of head, at maximum width with 19 ommatidia and at maximum length with 23 ommatidia. Vertexal margin with a median longitudinal impression, resulting from the bulging of the lateral ocelli, posterolateral corners of head rounded. Antennae 13-segmented, scapes rounded, surpassing the posterolateral corners of the head by the length of the three apical segments of the funiculus. First funicular segment with the same length of the second. Funiculus with a three segmented club. The apical funicular segment as long as the two anterior together. Ventral face of head flat.

Mesosoma in dorsal view with rounded scutum, almost covering the whole pronotum. Major width of scutum at tegula. Parapsidial lines distinct and in parallel to the main body axis. Axillae subtriangular and scutum-scutellar sulcus deeply impressed. Scutellum subquadrate to subtriangular, wider anteriorly than posteriorly, posterior margin rounded. Katepisternum subquadrate with inferior margin rounded; anepisternum subtriangular. Apex of procoxa fail to attain the anterior margin of katepisternum level. Propodeum basal face occasionally slightly concave, meeting the declivous face in rounded angles. In lateral view, petiole triangular, node rounded dorsally, ventrally straight. In dorsal view, petiole with a shallowly and wide median impression. Postpetiole much wider posteriorly, heart-shaped; ventrally with a vestigial anteromedian denticle. Gaster elongated.

Legs long and filamentous.