Eurhopalothrix lenkoi

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Eurhopalothrix lenkoi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Eurhopalothrix
Species: E. lenkoi
Binomial name
Eurhopalothrix lenkoi
Kempf, 1967

This species has been found nesting in a bromeliaceous plant growing on the soil.

Identification

Longino (2013): This species has the posterior face of the propodeum with large foliaceous crests instead of acute propodeal spines, a trait shared with Eurhopalothrix pilulifera from Central America. It differs in the much larger body size and the tooth-like development of the posterior face of the petiolar node. The head shape and pilosity patterns are much like Eurhopalothrix gravis. Measurements for workers of this species, as reported in Kempf (1967) are HW 0.91–0.99, HL 0.86–0.93, CI 100–106, SLI 9–12 (n=7). Measurements for the queen are HW 1.17, HL 1.12, CI 105. This is the largest New World species so far reported, with E. gravis being second largest. Queen HW is 1.22 x worker HW, the largest difference of any New World species. Most species for which queens and workers are known fall on a single line of allometry, with queen HW 1–1.1 x worker HW. The two largest species, E. gravis and E. lenkoi, deviate from the line with ratios 1.12 and 1.21, respectively.

Keys including this Species

Distribution

Brazil (Sao Paulo)

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (type locality).

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.

  • lenkoi. Eurhopalothrix lenkoi Kempf, 1967d: 358, figs. 6, 7 (w.q.) BRAZIL.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

(holotype). - Total length 4.1 (3.7-4.2) mm; head length 0.93 (0.86-0.93) mm; head width 0.96 (0.91-0.99) mm; thorax length 1.07 (1.02-1.17) mm. Cephalic index 100-106. Reddish brown; middle of cephalic dorsum, underside of head, disc of pronotum, metapleura and epinotum, petiolar and postpetiolar node, gaster more or less strongly infuscated; antennal scrobe, laterotergite of pronotum, mesonotum and mesopleura and legs contrasting by their light, yellowish brown color. Body very finely granulose or shagreened, and in part densely punctulate, opaque. Gaster densely punctulate but shining. Dorsum of head with fine, irregular, more or less longitudinal rugae; disc of pronotum with similar rugae which are more irregular and somewhat reticulate.

Head and body shape, and arrangement of the large specialized hairs as shown. Note the projecting and angulate occipital lobes. Mandibles finely and densely punctate, shining, with the external border practically straight; inner border with 9-11 teeth; basal tooth offset and small. Thoracic dorsum divided into a large, rounded promesonotunl and a much smaller and narrower epinotum, separated from each other by a shallow metanotal groove. Epinotal armature consisting of a pair of broad, sub diaphanous, thin plates containing the obtusely dentate epinotal spine and the not receding infradental lamella. Peticolar node cuboidal, as long as broad, anteriorly rounded, posteriorly sharply marginate and weakly bidentate, excised beneath the dentition; subpetiolar tooth distinct. Postpetiole reniform, transverse, twice as broad as petiolar node, with a postero-median and posterolateral impressions. Tergum and sternum I of gaster anteriorly marginate and carinulate; sternum I without a sagittal keel.

Large specialized hairs present in full complement, 18 (3 rows: 8-4-6) on head, 3 pairs on thorax, 1 pair on petiole, 2 pairs on postpetiole, 4 irregular longitudinal rows of 4 hairs each (lateral row often with only 3 hairs) on tergum I of gaster. These hairs have a thick, somewhat flattened and spoon-shaped head and are strongly bent at apex (subapressed) except on gaster where they are suberect. Leading edge of scapes fringed with spatulate hairs which are strongly curved basad; dorsal scape surface with similar subappressed spatulate ground hairs. Ground pilosity well-formed and conspicuous on head, pronotum, mesonotum, both nodes and legs, consisting of relatively large, abundant, subappressed scalelike hairs, which are almost half as long as the specialized hairs. Widely scattered and inconspicuous appressed smaller hairs on gaster.

Queen

(paratype). - Total length 5.6 mm; head length 1.12 mm; head width 1.17 mm; thorax length 1.55 mm. Cephalic index 105. Essentially the same as worker, but of darker color throughout, with large eyes (maximum diameter 0.21 mm), small ocelli, well-developed pterothorax. Pronotum with a pair of specialized hairs on each side; scutum with a median sagittal hairsless groove, flanked on each side by a series of narrowly spatulate, suberect hairs; a specialized hair on each of the paraptera; scutellum with a pair of specialized hairs, posteriorly prominent, feebly bilobed, overhanging the epinotum which practically lacks a basal face. Petiolar node with the same posteriorly carinate border which is excavate beneath. Specialized hairs on tergum I of gaster thinner, erect, more numerous, arranged in 4 irregular longitudinal rows. Wings unknown.

Type Material

Longino (2013) - Holotype worker: Brazil, São Paulo: Caraguatatuba, State Forest Reserve, 40 m elevation, 7-14 Jul 1962, nesting in Bromeliaceous plant growing on a fallen tree trunk in the woods (K. Lenko, No. 2183) Museu de Zoologia da Universidade de Sao Paulo? "Departamento de Zoologia, São Paulo"] (not examined). Paratypes: workers and queen, same data as holotype MZSP; Ilha de Vitória, 25km off the shore of Ubatuba, 26 Mar 1964, nesting in a bromeliaceous plant growing on the soil (K. Lenko, No. 4031).

References

  • Kempf, W. W. 1967d. Three new South American ants (Hym. Formicidae). Stud. Entomol. 10: 353-360 (page 358, figs. 6, 7 worker, queen described)
  • Longino J. T. 2013. A review of the Central American and Caribbean species of the ant genus Eurhopalothrix Brown and Kempf, 1961 (Hymenoptera, Formicidae), with a key to New World species. Zootaxa. 3693:101-151. doi:10.11646/zootaxa.3693.2.1