Eurhopalothrix clypeata

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Eurhopalothrix clypeata
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Eurhopalothrix
Species: E. clypeata
Binomial name
Eurhopalothrix clypeata
Brown & Kempf, 1960

Eurhopalothrix clypeata fmnhins0000095828 p 1 high.jpg

Eurhopalothrix clypeata fmnhins0000095828 d 1 high.jpg

Specimen Labels

Known only from the worker holotype.

Identification

It is most similar to Eurhopalothrix pilulifera and Eurhopalothrix alopeciosa, sharing the small size; a similar arrangement and number of erect setae, these almost circular, nearly as broad as wide; and abundant ground pilosity that is strongly flattened and conspicuous. Eurhopalothrix clypeata has an arcuate transverse carina on the clypeus, a character so far unique in the genus. (Longino 2013)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Guyana (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

Known only from the worker caste.

Nomenclature

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

  • clypeata. Eurhopalothrix clypeata Brown & Kempf, 1960: 205, fig. 37 (w.) GUYANA.

Description

Worker

Holotype: TL 2.0, HL 0.52, HW 0.50 (CI 96), scape L 0.32, maximum eye diameter about 0.025, WL 0.52 mm.

This species is a rather typical small member of the holaui group, distinguished above all by its peculiar clypeus, which is divided by an arcuate transverse carina into a large, sloping, concave anterior part and a small, weakly convex, triangular posterior part. As in Eurhopalothrix gravis, Eurhopalothrix alopeciosa and the Old World Eurhopalothrix australis, clypeata is "bald", i.e., the part of the verticocciput occupied by the specialized (in this case very strongly clavate and erect) hairs either lacks the small appressed-squamiform ground pilosity entirely, or else has it very noticeably more sparsely represented than on the frontal section of the head and on the more lateral sections of the occipital lobes. The "bald spot" coincides more or less exactly with the field occupied by the larger specialized hairs, and is frequently more or less accentuated by the presence of whitish foreign material on other parts of the dorsum of the head. In the clypeata holotype, the ground pilosity is much sparser and more restricted in distribution than it is in alopeciosa, gravis, australis or pilulifera. It is absent or extremely reduced, not only in the vicinity of the larger hairs, but also in the middle of the frontal section, on the middle of the clypeus, and on the alitrunk, petiole and gaster. Only on the head, postpetiole, scapes and legs is the ground pilosity reasonably distinct. The virtual absence of the small ground hairs from the gaster is especially striking; this can scarcely be due to abrasion, because all 16 of the larger, erect, thick clavate hairs are present on the first gastric tergite (4 rows of 4 hairs each). Large hairs present in full complement (3 pairs on alitrunk, with one hair missing through abrasion); they all are very thick-clavate, erect, but not quite so extremely inflated and "pompon-like" as in Eurhopalothrix pilulifera or alopeciosa.

The alitrunk is similar to that of Eurhopalothrix speciosa, but in clypeata it is a little shorter and higher and more strongly convex above in profile; the mesonotum is rather prominent, but is not longitudinally carinate; metanotal groove present but shallow. Petiolar node more compressed anteroposteriorly than in speciosa, its anterior face steeply sloping and meeting the summit through a narrowly rounded curve, behind which the convex posterodorsal face slopes away to the rear. Seen from above, the node is very slightly broader than long, with a nearly straight (very feebly concave) anterior margin. Body punctulate-granulose, opaque, the punctures more distinct on gaster. Center of clypeus smooth and shining; mandibles feebly sculptured and weakly shining. Color medium ferruginous, gaster slightly infuscated except at its base.

Type Material

Holotype a unique [NAW] taken by N. A. Weber between the River Cuyuni and the River Mazaruni, British Guiana, presumably in forest, on September 7, 1935.

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 205, fig. 37 worker 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