Eurhopalothrix elke

The type specimens "were extracted from topsoil of primary hill diperocarp forest by Winkler extractors. The type locality is situated at the slopes at Gunung Mulu in about 250 m in the centre of Gunung Mulu National Park in Sarawak, Malaysia." (Mezger & Pfeiffer 2010)

Identification
Mezger & Pfeiffer (2010) - Separated from all other species of E. platisquama group by unique number of two large, erect setae on upper section of head with no additional setae near midline of head. Setae of E. elke twice as long as of all other known species. Postpetiole of E. elke without any erect setae, unlike all other species which show one seta on each side of postpetiole. Eurhopalothrix seguensis bears four erect setae on its upper section of head altogether, consisting of one pair of smaller setae situated in middle of posterior section of head, flanked by one single larger seta on each side posterior to it and distant from midline of head. One group of four small setae present in Eurhopalothrix platisquama and Eurhopalothrix dubia. Eurhopalothrix dubia has two further setae each on left and right side of upper section of head situated anterior and laterad of group of four setae. Surface structure differs to that from other species: distances between squamiform hairs larger than in all other species and foveolae of integument almost as large as in E. dubia, but smaller than in E. platisquama and E. seguensis.

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

Nomenclature

 *  elke. Eurhopalothrix elke Mezger & Pfeiffer, 2010: 136, figs. 2, 6, 10, 14 (w.) BORNEO.

Worker
Holotype: CI 88, DSe 0.39, EY 0.08, HL 0.73, HW 0.83, ML 0.22, MW 0.24, PeL 0.40, PeW 0.31, PPL 0.22, PPW 0.48, PSD 0.06, PW 0.50, SeL 0.09, SL 0.43, WL 0.85. Paratypes: minimum and maximum (n = 7): CI 87-88, DSe 0.38-0.40, EY 0.07-0.08, HL 0.72-0.73, HW 0.82-0.85, ML 0.21-0.23, MW 0.24-0.28, PeL 0.39-0.40, PeW 0.29-0.31, PPL 0.23-0.24, PPW 0.47-0.49, PSD 0.05-0.06, PW 0.50-0.52, SeL 0.08-0.09, SL 0.43-0.44, WL 0.85-0.86.

Whole body densely foveolate. Almost all parts of head, mesosoma and gaster covered with flat-surfaced, squamiform hairs with feather-like endings, except for sides of mesosoma and underside of petiole. Head subtriangular, wider than long. Occiput concave, with shallow depression in middle, less prominent than in other species. Occipital lobes considerably rounded. On top of head only two conspicuous club-shaped standing setae, longest setae of its kind among E. platisquama group. Distance between setae larger than in E. seguensis. Eye medium large, little larger than in E. seguensis, but smaller than in E. dubia, with at least 20 ommatidia. Clypeus broader than long, faintly concave in front. Frontal carina bordering deep antennal scrobe below eye, allowing total reception of antenna. Scape expanded anterad, like in other species of group. Apart from silvery hairs of squamiform pilosity, scape bearing two rows of setae at outer edge: one directly on corner with ten thick, long setae getting shorter distally; second with 12 smaller setae, proximal setae same size of squamiform hairs, but getting larger distally. Antennal segments covered with fine simple hairs. Triangular mandible with small, squamiform hairs, 1.1 times as broad as long, i.e., ratio smaller than in E. dubia and E. platisquama. Masticatory margin with 11 almost identical teeth.

Mesosoma convex, but declivity of mesosoma less steep than in E. seguensis. Anterior part covered with dense squamiform hairs, which also occur on lateral pronotum. Mesopleuron and metapleuron without any pilosity. Propodeal spiracle conspicuous, same size as in E. dubia and E. platisquama, but little larger than in E. seguensis.

Petiole and postpetiole: Upper parts densely covered with squamiform hairs, on ventral parts such pilosity absent. Shape and pilosity almost identical to that of other species of group, but in contrast to those lacking conspicuous setae.

Pilosity on gaster much less dense than on mesosoma. Pilosity of first tergite with silvery squamiform hairs, some foveolae present between them but without standing setae. Second tergite with four squamiform hairs and two setae. Third tergite with four squamiform hairs and four setae. Fourth tergite with three pairs of setae, but no squamiform hairs.

First sternite glossy, with only few small, shallow foveolae and few squamiform hairs. Lateral margin of first sternite with some larger and deeper foveolae, bearing some small setae. Second sternite: six setae and same number of squamiform hairs present on each side. Third sternite: six setae and four squamiform hairs. Fourth sternite with four setae.

All parts of legs densely foveolate. Coxae with only few squamiform hairs. On femurs some squamiform hairs dis-tally. Tibiae distally with some setae; smooth transition be-tween them and pilosity on proximal part of more squamiform character. Pretarsi with six setae each, beside simple hairs. Other tarsal segments only with simple hairs.

Colour: basic colour dark reddish brown on all body parts. Mandible, antenna and legs slightly paler. Squamiform ground pilosity of silvery white colour, setae on head and gaster white to ivory. Pilosity of antenna and legs similar but colour of pilosity brighter than ground pilosity.

Type Material
Holotype: worker. Malaysia: Sarawak, Gunung Mulu National Park, vicinity of Camp 1, 250 m a.s.l. (04° 03' 04" N, 114°51' 43" E), 12.V.2006, leg. D. Mezger, collection code: DI 04 B. Paratypes: same data as holotype, pin codes: AntBase.Net No. 1644-1645, 2 workers (ABNC), same data as holotype, 3 workers (FRCK,, SMNK); same locality, but collected on 02.IX.2006, collection code: DI 11 B, 1 worker (ANIC); same locality, but collected on 19.IX.2007, collection code: DI 19 B, 1 worker (SMNK).

Etymology
Named in dedication to Mrs. Elke Mezger, mother of the first author. Together with her husband, Mr. Karl-Heinz Mezger, she has been supporting her son in his study of biology from the very first and thus enabled the discovery of this species. The specific name is an arbitrary combination, to be treated as a noun in apposition.

References based on Global Ant Biodiversity Informatics

 * Mezger D., and M. Pfeiffer. 2011. Partitioning the impact of abiotic factors and spatial patterns on species richness and community structure of ground ant assemblages in four Bornean rainforests. Ecography 34: 39-48.
 * Mezger D., and M. Pfeiffer. 2011. Partitioning the impact of abiotic factors and spatial patterns on species richness and community structure of ground assemblages in four Bornean rainforest. Ecography 34: 39-48.
 * Mezger, D., and M. Pfeiffer. "Eurhopalothrix elke, a new species from Borneo, and a key to the species of the E. platisquama group (Hymenoptera: Formicidae)." Myrmecological News 13 (2010): 133-139.
 * Mezger, D.; Pfeiffer, M. 2010. Eurhopalothrix elke, a new species from Borneo, and a key to the species of the E. platisquama group (Hymenoptera: Formicidae). Myrmecological News 13:133-139.
 * Pfeiffer M., and D. Mezger. 2012. Biodiversity Assessment in Incomplete Inventories: Leaf Litter Ant Communities in Several Types of Bornean Rain Forest. PLoS ONE 7(7): e40729. doi:10.1371/journal.pone.0041100
 * Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58