Epelysidris brocha

This monotypic species is only known from workers that have been found in soil of a moss forest and tropical rainforest (as stated on the labels from the two known collections).

Identification
The single species of the genus, the worker can be diagnosed using the same features that separate Epelysidris from other genera:

Bolton (1987) - Epelysidris is easily diagnosed among members of the Solenopsis-group by the remarkable pair of lobes on the basal border of each mandible, unknown in any other genus of the group. The structure of the mandibles and clypeus together, combined with the 3,2 palp formula, isolates Epelysidris from all other myrmicine ant genera.

Conversely characters regarded as apomorphic in Epelysidris include the development of lobes on the mandibular basal margin, the presence of large triangular teeth on the anterior clypeal margin, and the development of narrow cuticular crests down each side of the propodeal declivity. The M. modestus-group is plesiomorphic in these, with unarmed basal mandibular margins, lacking clypeal teeth, and lacking cuticular crests on the propodeal declivity.

The real affinities of Epelysidris appear to lie with Monomorium and its immediate allies, from which it has evolved by gross modification and specialization of the mandibles and clypeus. Differences in the mandible between Epelysidris and those Monomorium species with 5 teeth include lengthening and narrowing of the blade in the former and the opening of diastemata between the teeth following the preapical, and the autapomorphic development of lobes on the basal border. In the case of the clypeus Epelysidris has modified the median portion by narrowing and raising it up very markedly, and narrowing its posterior section between the antennal insertions. The pair of longitudinal clypeal carinae, characteristic of Monomorium, is very reduced and fades out anteriorly in Epelysidris. On the other hand the pair of teeth on the anterior clypeal margin, which mark the apices of the clypeal carinae in many Monomorium species, are very much enlarged in Epelysidris and are divorced from the carinae altogether.

Ito and Yamane (2014) - We compared the male of Epelysidris brocha with those of Monomorium floricola, Monomorium chinense and three unidentified Asian species. It is in most characters very similar to the males of above-mentioned species and those of the Monomorium species for which the male sex has been described (Smith, 1943; Ettershank, 1966; Bolton, 1987; Ogata, 1991). The following conditions may be noted: occipital carina distinct on the median portion of posterior margin of occiput; costal and subcostal veins of forewing almost fused in basal half; first discoidal cell present (this condition is also seen in some African species; Bolton, 1987). As a whole we did not find a strong reason to separate this species in male morphology from other species of Monomorium.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia.

Biology
Ito and Yamane (2014) - ABSTRACT. This study reports on reproduction by ergatoid queens of Monomorium brocha (Bolton) collected in the Bogor Botanic Garden, West Java, Indonesia. One colony fragment comprised 20 ergatoid queens that showed variable ovariole numbers. All but one of the dissected queens had mated, but the ovarian condition varied among individual queens. Ergatoid queens can be easily distinguished from workers by morphological characteristics such as large compound eyes and a suture between the pronotum and mesonotum. The development of the mesonotum varies among ergatoid queens, but has no correlation with ovariole number. The colony (code FI01-151, Fig. 1) of M. brocha was found underground in the Shorea forest of Bogor Botanic Garden (6˚35’S, 106˚47’E, and ca 240 m alt.), West Java, Indonesia, on 10 August 2001. Almost half of the colony was collected with an aspirator. Some individuals were dissected under a binocular microscope immediately after collection. The remaining individuals were kept in a container measuring 20 × 10 × 5 cm, which contained a small artificial nest (5 × 5 × 2 cm) as a nest chamber. The floor of the container was covered with plaster to maintain humidity. In the laboratory, the colony was provided with several kinds of dead arthropods including termites, mealworms, crickets, and particles of sweet cookies. Workers also took honey water. A small sub-colony composed of ten queen pupae, about ten male pupae and 30 adult workers were divided from the original colony and kept in another artificial nest. Sexuals emerged from these pupae within a few weeks. After two months, all wingless queens in the isolated sub-colony (number of emerged individuals = 6) were dissected to check their reproductive status. Voucher specimens are deposited in Bogor Zoological Museum.

Colony composition

The colony was collected from hard soil on the forest floor. The colony fragment contained ca 220 wingless females, 40 males, and several immatures. The wingless females were of two types: one with a large abdomen, and one with a small abdomen (Fig. 1). Dissection of some individuals of both types showed that the former had a spermatheca and 6 to 14 ovarioles per individual (average ± SD, 9.2 ± 2.1, N= 17), while the latter had two ovarioles and lacked a spermatheca (N= 20), indicating that the former type are ergatoid queens and the latter are workers. The overall body size of workers was slightly smaller than that of ergatoid queens [head width: 0.73 ± SD 0.025 mm in queens (N= 17), 0.64 ± 0.023 mm in workers (N= 20), Welch two sample t-test, t = 11.3, df = 31, P < 0.0001]. Furthermore, both female types can be distinguished by the following morphological characteristics: the compound eyes of ergatoid queens were remarkably larger than those of workers in the long axis [0.12 ± 0.011 mm in queens (N= 13), 0.05 ± 0.004 mm in workers (N= 13), Welch two sample t-test, t = 18.3, df = 15, P < 0.0001], while workers had a slightly elongated heads [proportion of head length to head width: 1.05 ± 0.028 in queens (N= 16), 1.12 ± 0.032 in workers (N= 20), Mann-Whitney U-test, Z = −4.89, P < 0.0001]. The structure of the thorax, especially the development of the mesonotum, varied among ergatoid queens; some of them were very similar to workers but the pronotum was separated from the mesonotum by a suture in all ergatoid queens while the pronotum was fused with the mesonotum without a suture in workers. Four ergatoid queens had a remarkably developed thorax with a “wing base”: however, their mesonotum was not well developed compared to that of alate queens of other Monomorium species. The ovariole number of these four ergatoid queens with wing bases was nine (3 queens) or 11 (one queen), being not significantly different from that of queens without a wing base (Welch two sample t-test, t = 0.67, df = 10, P =0.71). This indicates that the development of the thorax is not positively correlated with ovariole number. The majority of ergatoid queens had two degenerated ocelli, while workers completely lacked ocelli. Based on this difference, 20 ergatoid queens and 200 workers were recognized among the females in this colony fragment. Details of brood composition were not examined, but the sex and caste of 67 randomly selected pupae collected in the field were checked: these included 33 workers, nine ergatoid queens, and 21 males.

Reproduction by ergatoid queens

All but one of the ergatoid queens had mated (N= 17). Ovary development of ergatoid queens dissected immediately after collection varied greatly: two had well developed ovaries, one had only two developing oocytes without yellow bodies, and another two mated queens and one virgin queen had no developing oocytes. These results indicate that this species exhibits polygyny with variation in queen fecundity. The relationship between the fecundity of queens and their age was unclear, because there were no indications of age difference among queens. Under laboratory conditions, many queens held eggs in their mandibles, and carried eggs inside the nest chamber. Queens without eggs in their mandibles often tried to pick up eggs held by other queens, though this was rarely successful. Any clear dominance behavior was not observed among ergatoid queens. Most workers had a few developing oocytes.

Three of six ergatoid queens that emerged in an isolated colony had mated, indicating that intracolonial mating occurred, even though mating behaviour was not observed.

Nomenclature

 *  brocha. Epelysidris brocha Bolton, 1987: 280, figs. 16, 17 (w.) BORNEO. Combination in Monomorium: Fernández, in Heterick, 2006: 79; Fernández, 2007b: 131; in Epelysidris: Ward et al., 2014: 15.

Worker
Holotype. TL 3.8, HL 0.78, HW 0.64, CI 82, SL 0.83, SI 130, PW 0.46, AL 1.02.

Apical and preapical of the 5 mandibular teeth not separated by a diastema, but with a diastema between each of the remaining teeth. All teeth narrowly triangular and sharp. First lobe on basal margin of mandible more broadly triangular than the basal tooth and conspicuously more bluntly rounded, close to the basalmost tooth of the masticatory margin but directed posteriorly when the mandibles closed. Second lobe confluent with first basally, slightly lower and more broadly triangular than the first lobe. Blades of mandibles unsculptured except for small hair-pits. Mandibles downcurved, rather more strongly so at apex so that in full-face view the apical tooth appears to be directly below the preapical. PF 3,2. Anterior clypeal margin with a slightly prominent median section which is bounded by a pair of sharp triangular teeth; the margin between the teeth more or less transverse. Median clypeal seta conspicuous. Median portion of clypeus narrow and suddenly raised, evenly convex anteriorly but posteriorly with vestiges of a pair of clypeal carinae which converge posteriorly. Space between these carinal vestiges flat to very shallowly transversely concave. Posteromedian section of clypeus very narrow where it passes between the small frontal lobes; the latter not wholly concealing the condylar bulbs of the scapes. Antennal scapes long (SI > 125), when laid straight back from their insertions considerably exceeding the occipital margin. Funicular segments 1-8 ca 0.48, the club (funicular segments 9-11) ca 0.70; club segments relatively narrow but very much longer than any of the preceding funicular segments. Eyes situated at about the midlength of the sides of the head: Eyes small, about 0.13 x HW, consisting of an outer ring of 8 ommatidia surrounding a single central ommatidium. Outline shape of head as in Fig. 17. Shape of alitrunk, petiole and postpetiole as shown in Fig. 16. Metanotal groove broad and conspicuously impressed, traversed by short but distinct cross-ribs. Propodeal spiracle large, with a circular orifice which is directed somewhat posteriorly, not opening flush with the side of the sclerite. Propodeal dorsum and declivity meeting in a blunt angle in profile, the declivity almost vertical and bounded on each side by a very narrow cuticular crest which is continuous with the metapleural lobes below and just reaches onto the dorsum above. Metapleural lobes small and rounded. Anterior peduncle of petiole long and narrow, subtended by a fine strip-like anteroventral process. Petiolar spiracle at the node. Postpetiole about the same size as the petiole node in profile but somewhat more broadly rounded. In dorsal view the petiole node broader than long; postpetiole also broader than long but more nearly subglobular than the petiole and somewhat narrower. All dorsal surfaces of the head and body with elongate simple standing hairs. Antennal scapes and middle and hind legs with suberect to subdecumbent projecting hairs, the longest of which are equal to or slightly longer than the width of the appendage on which they arise. Head smooth and shining, unsculptured except for scattered hair-pits. Promesonotum as head but the propodeal dorsum with faint shagreening.

Mesopleuron finely and densely punctulate-shagreenate and the metapleuron with a few longitudinal rugulae; otherwise sides of alitrunk unsculptured and shining. Petiole and postpetiole nodes and gaster unsculptured except for hair-pits. Peduncle of petiole with fine punctulation dorsolaterally. Colour uniform dull yellow.

Male
Ito and Yamane (2014) - (n = 4). Head width including eye 0.64 – 0.67 (mean: 0.66), head length 0.56 – 0.58 (0.57), eye width 0.22 – 0.23 (0.23), eye length 0.28 – 0.30 (0.29), scape length 0.17 – 0.18 (0.18), mesonotal width in dorsal view 0.60 – 0.63 (0.62).

Structure. Head, excluding eyes, as long as broad, much narrower at mandibular bases than at the level behind eyes, with evenly rounded posterior margin. Occipital carina recognizable as a blackened low keel in median portion of posterior margin of occiput. Clypeus clearly demarcated from frons, medially strongly convex dorsad, with straight anterior margin. Mandible moderately developed; masticatory margin with 3 teeth; first (apical) longest and third (basal) shortest or subequal to second; first and second sharply pointed at apex, close to each other; basal margin with a denticle located close to basal tooth of masticatory margin (the denticle looks a fourth tooth). Eye very large, distinctly protruding from outer margin of cranium; malar space (distance between mandibular base and anterior margin of eye) short. Ocelli rather large; their diameter as long as antennal pedicel; distance between lateral ocelli larger than that between median ocellus and lateral ocellus, 1.5 times as long as ocellar diameter. Antennal socket close to posterior margin of clypeus; frontal lobe poorly developed, not covering antennal socket; frontal carina almost absent. Antenna 13-segmented; scape cylindrical, when laid back not extending beyond the level of the anterior margin of median ocellus, as long as segments 2 (pedicel) and 3 combined; segments 3 to 13 gradually becoming longer toward antennal apex; apical segment twice as long as segments 11 and 12 combined. Mesosoma massive, broader than head excluding eyes. Seen from above pronotum reduced to a narrow belt; lateral face posterovetrally sloping steeply to anterior margin of anepisternum. Mesoscutum huge, with weak median suture and notaulices that are often evanescent, seen from above as broad as long, and seen in profile roundly convex dorsad; mesoscutellum separated from mesoscutum by a deep furrow with the bottom provided with short keels, broader than long, strongly convex dorsad; anepisternum well differentiated from katepisternum by a suture (or a series of punctures), dorsally margined with a carina. Metanotum a very narrow zone, well defined between mesoscutellum and propodeum; metapleuron differentiated from mesopleuron, but completely fused with propodeum in lower half. Propodeum weakly convex posterodorsad; dorsal and posterior faces poorly differentiated; weak lateral carinae present on posterior face; with propodeum in full-face view spiracle located high on lateral face, at some distance from both dorsal and posterior margins of propodeum. Petiole with a distinct peduncle; petiolar node in dorsal view broader than long, in profile as long as high, apically narrowed with round apex; postpetiole as high as petiole, but more globular than the latter, with more rounded apex. First gastral tergite large, slightly shorter than the remaining tergites combined, seen from above with almost parallel sides.

Sculpture. Head extensively covered with dense sculpture and mat; frons and area behind ocelli with weaker sculpture and somewhat shiny; mandible superficially sculptured and shiny; antennal scape and pedicel smooth and shiny; other segments densely and minutely sculptured. Pronotum, mesoscutellum and metanotum, and meso- and metapleura smooth and shiny; mesoscutum and propodeum weakly sculptured. Petiolar and postpetiolar nodes and gastral tergites and sternites smooth and shiny; petiolar peduncle densely punctate.

Pilosity. Dorsa of head, mesosoma and waist, and gastral tergites and sternites with many erect hairs that are longer than antennal pedicel; clypeus with a long median seta; antennal scape with erect hairs that are shorter than diameter of scape; tibiae of all legs with numerous obliquely standing hairs on outer faces.

Wing venation. The terminology follows the system adopted by Hölldobler and Wilson (1990). Forewing: costal vein almost fused with subcostal vein half way from wing base; pterostigma distinct and large; marginal cell open apically; submarginal cell open near pterostigma; first discoidal cell small, closed; cubito-anal crossvein (cu-a) complete or not reaching anal vein; cubital vein and median vein short, not reaching outer margin of wing. Hindwing: venation reduced; only median cell enclosed with strong veins.

Type Material
Holotype worker, East Malaysia: Sarawak, Mt Dulit, 4000 ft, moss forest, 21.x.1932, Oxford Univ. Expd. B. M. 1 933-254. Ants nest in soil under moss and rocks (B. M. Hobby & A. W. Moore). Paratypes. 8 workers with same data as holotype (BMNH; ). Paratypes. TL 3.7-4.0, HL 0.76-0.80, HW 0.62-0.64, CI 80-83, SL 0.78-0.83, SI 126-132, PW 0.44-0.48, AL 0.96-1.02 (7 measured). As holotype but maximum diameter of eye 0.11-0.13 x HW and the eye with 9-12 ommatidia in total. The eye consists of an outer ring of 8-9 ommatidia which encloses1-3 central ommatidia.