Eurhopalothrix emeryi

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Eurhopalothrix emeryi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Eurhopalothrix
Species: E. emeryi
Binomial name
Eurhopalothrix emeryi
(Forel, 1912)

Eurhopalothrix emeryi casent0181833 p 1 high.jpg

Eurhopalothrix emeryi casent0181833 d 1 high.jpg

Specimen Labels

Synonyms

Mann reported the species as nesting in small colonies beneath stones or logs deep in the woods, and that individuals are hard to discern on account of their neutral color and habit of remaining motionless when disturbed. All of the worker specimens collected during the recent survey were taken from sifted litter. (Sarnat and Economo 2012)

Identification

Eurhopalothrix emeryi workers can be distinguished from Eurhopalothrix insidiatrix (the only Fijian congener) by the more groomed appearance of the cephalic and mesosomal rugae.

Keys including this Species

Distribution

The type locality was given as Australia but is believed to be an error. This species is only known from Fiji and not known to occur in Australia.

Distribution based on Regional Taxon Lists

Indo-Australian Region: Fiji.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Little is known about the biology of most species in this genus. Nests are rarely found, and queens and males have not been collected for many species. Longino (2013) summarized their biology "Eurhopalothrix specimens are encountered almost exclusively in samples from mass extraction techniques that recover small arthropods in sifted litter, rotten wood, and soil. Densities, at least in the northern Neotropics, are usually low, with workers occurring in < 10% of quantitative samples of 1 m2 litter plots, but occasionally may reach densities as high as 40% of samples. Live colonies of Old World Eurhopalothrix were observed by Wilson (1956) and Wilson and Brown (1984), and a Costa Rican colony of Basiceros manni was observed by Wilson and Hölldobler (1986). All basicerotines, including Eurhopalothrix, are thought to be predators in tropical leaf litter, relying on stealth or sit-and-wait techniques. Sampled specimens are often coated with a thin layer of clay, especially on the face, which is thought to function as camouflage, enhancing crypsis (Hölldobler & Wilson, 1986). Highly specialized spatulate setae may be instrumental in acquisition and adherence of the clay layer (Hölldobler & Wilson, 1986)."

Castes

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • emeryi. Rhopalothrix emeryi Forel, 1912n: 58 (q.) AUSTRALIA. Combination in Eurhopalothrix: Brown & Kempf, 1960: 230. Senior synonym of elegans: Brown & Kempf, 1960: 230.
  • elegans. Rhopalothrix (Rhopalothrix) elegans Mann, 1921: 467, fig. 25 (w.) FIJI IS. Junior synonym of emeryi: Brown & Kempf, 1960: 230.

Type Material

Forel described emeryi from a female which he said was from "Australie. Ma Collection". Through the courtesy of Dr. C. Besuchet, of the Museum d'Histoire Naturelle of Geneva, we have been able to examine the holotype of emeryi and to compare it with syntype workers of elegans and a winged female of this species from Nadarivatu, Fiji (E. C. Zimmerman leg.); they show good agreement. We believe that Forel's original locality citation was based on an error, and until contradictory evidence is forthcoming, we consider that emeryi is restricted to Fiji. In addition to Viti Levu, it has been taken on Vanua Levu and Oval au in the Fiji Islands. (Brown and Kempf 1960) Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Taylor (1980) - Dimensions [smallest (Nadarivatu) and largest (Mt Tomanivi) available specimens, selected by HW measurement]. — TL ca 5.0, 5.5; HL 1.24, 1.35; HW 1.20, 1.27; CI 97, 94; ML 0.34, 0.37; M127, 27; SL 0.73, 0.77; S1 61, 61; maximum diameter of eye 0.12, 0.15; PW 0.73, 0.83; WL 1.44, 1.59; petiolar node width 0.33, 0.35; postpetiole width 0.65, 0.73; gastral width 0.95, 1.07.

Additional description — Basal halves of mandibles coarsely and closely punctate. Clypeus, edges of antennal scrobes, and extreme lateral and apical portions of occipital lobes coarsely punctate-rugose. Frons otherwise bearing strong smooth costae, shining when clean; their reflections regularly interrupted by minute shallow pits marking hair bases, which do not significantly break costular surfaces. Intercostal grooves strong, almost as deep as wide, generally slightly wider than adjacent costae; frequently packed with greyish dirt or secreted material. The costae arranged in more or less parallel series, one set approximately longitudinal between the antennal scrobes, and others, behind the level of the antennal insertions, parallel to the diverging sides of the head and to the transverse occipital border. They thus form an approximately triangular figure around the centre of the frons, where there is a tendency to fusion and rugosity.

Anterodorsal and dorsolateral areas of pronotum coarsely and deeply rugoreticulate, lower part of anterior face transversely costulate, like posterior part of head, the costae extending to the ventrolateral areas of the sclerite. Mesosomal dorsum otherwise longitudinally costulate; mes- and metepisterna and sides of propodeum with diagonal costae sloping forwards; declivitous face of propodeum finely shagreened.

Specialised hairs additional to those of scapes and the three terminal gastral segments less strongly differentiated than in other species, two to three times longer than those of ground pilosity, barely thicker; three pairs on head and two on promesonotum. First gastral tergite with about 10 erect specialised hairs arranged in two loose longitudinal rows.

Queen

Taylor (1980) - The emeryi holotype alate female is matched closely by Mann's Eurhopalothrix elegans (=emeryi) syntype female from Nadarivatu. Both these specimens resemble workers from the E. elegans type-series, and those from Nandrau and Navai, in those features which distinguish them from the Eurhopalothrix insidiatrix worker types.

Specialised hairs differentiated from ground pilosity even less strongly than in workers; occupying similar positions on head and gaster. Mesosoma of holotype badly damaged by mounting pin, bearing at least one pair of erect hairs on pronotum and two on mesocutum. This configuration confirmed by the elegans syntype, which in addition has one pair of hairs on the mesoscutellum.

References

  • Brown, W. L., Jr.; Kempf, W. W. 1960. A world revision of the ant tribe Basicerotini. Stud. Entomol. (n.s.) 3: 161-250 (page 230, Combination in Eurhopalothrix, and senior synonym of elegans)
  • Forel, A. 1912o. Einige neue und interessante Ameisenformen aus Sumatra etc. Zool. Jahrb. Suppl. 15("Erster Ba Band: 51-78 (page 58, queen described)
  • Sarnat, E. M.; Economo, E. P. 2012. The ants of Fiji. University of California Publications in Entomology 132:1-384. PDF
  • Taylor, R. W. 1980b. Australian and Melanesian ants of the genus Eurhopalothrix Brown and Kempf - notes and new species (Hymenoptera: Formicidae). J. Aust. Entomol. Soc. 19: 229-239