Rhopalothrix subspatulata

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Rhopalothrix subspatulata
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Rhopalothrix
Species: R. subspatulata
Binomial name
Rhopalothrix subspatulata
Longino & Boudinot, 2013

Rhopalothrix subspatulata inbiocri001259541 p 1 high.jpg

Rhopalothrix subspatulata inbiocri001259541 d 1 high.jpg

Specimen Labels

Longino and Boudinot (2013) - This species occurs in lowland rainforest, from 50–800m elevation. Of the approximately 50 workers known, one was collected in a Malaise trap sample and the rest were in Berlese or Winkler samples. The Winkler samples were of sifted litter and rotten wood on the forest floor; the Berlese samples were cores of forest floor litter and about 5–10cm of the mineral soil beneath. At La Selva Biological Station, 3% of 208 Berlese samples and 2% of 640 miniWinkler samples contained workers. Given that each miniWinkler sample covered an area about 60 times greater than a Berlese sample (1 sq. m versus 165 sq. cm), R. subspatulata was far more abundant in Berlese samples. This suggests that R. subspatulata, and perhaps Rhopalothrix in general, are subterranean, nesting and foraging in mineral soil, and perhaps only rarely venturing up into the litter layer. The pale color and greatly reduced eyes also suggest subterranean habits.

Alate queens were collected in three of 50 canopy fogging samples from the ALAS project at La Selva[1]: 8 October and 10 November 1994 and 28 December 1999 (mid to late wet season). This suggests that the species mates above ground and has normally dispersing queens.

Identification

Sharing with R. nubilosa and Rhopalothrix weberi a characteristic labrum shape: anterior margin of labrum with two long, bluntly triangular lobes, sinus between them deep, length of anterolateral lobe longer than or about equal to distance from base of sinus to transverse carina at base of labrum; worker hardly differing from R. weberi, being slightly larger (HW > 0.40) and with larger mandibular teeth; queen differing from R. weberi in stronger facial concavity and carina medial to compound eye; worker differing from Rhopalothrix nubilosa in smaller size (< 0.50) and fewer squamiform setae on first gastral tergite (six versus about twelve).

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Costa Rica (type locality), Nicaragua.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Longino and and Boudinot (2013) - Knowledge of the biology of the Rhopalothrix isthmica clade of Rhopalothrix is conjectural; a nest has never been recovered and a live specimen never seen. What we know is based on locations and frequencies of capture using various mass-sampling methods. Specimens are known from wet to moderately seasonal forest, from sea level to 2140 m elevation. At higher elevation, they are found in diverse mesophyll forest and in forests with various combinations of Liquidambar and montane oak. In Costa Rica, they are restricted to the wet forests of the Atlantic slope, to 1500 m on the Barva Transect in the Cordillera Volcánica Central and to 800 m in the Cordillera de Tilarán. The genus is unknown from the Monteverde cloud forest at 1500 m, the lowland wet forests of the Osa Peninsula, and the lowland tropical dry forests of Guanacaste, in spite of intensive collecting efforts in these areas. Further north in Central America they can occur at higher elevations.

In quantitative sampling at La Selva Biological Station, in the Atlantic lowlands of Costa Rica, occurrences were relatively more frequent in soil/litter cores than in samples of sifted litter from the soil surface. This suggests that nests are subterranean, with workers only occasionally venturing up into the litter layer. Dealate queens are known for a few species, occurring occasionally in Winkler or Berlese samples. Alate queens of one La Selva species were found in canopy fogging samples, one each in two separate fogging events. Oddly, alate queens have not been found in the many Malaise samples from La Selva. Males remain unknown.

Castes

Males have yet to be collected.

Worker

Queen

Nomenclature

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

  • subspatulata. Rhopalothrix subspatulata Longino & Boudinot, 2013: 316, figs. 1D, 2D, 3B, 4, 12, 16 (w.q.) COSTA RICA.

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

Description

Worker

HW 0.42–0.49 (n=14); mandible with two closely-spaced short triangular teeth at base, a smaller tooth about mid-distance between basal teeth and base of subapical tooth, reclinate denticle at base of subapical tooth absent, apical tooth short, about 1/3 × length of subapical tooth, intercalary teeth minute; labrum about as long as broad, with two long, bluntly triangular lobes, sinus between them deep, length of anterolateral lobe longer than or about equal to distance from base of sinus to transverse carina at base of labrum; erect setae on leading edge of scape stiff but narrow, hardly clavate, unlike the squamiform setae typical of many other species; arcuate promesonotal groove and metanotal groove moderately impressed; propodeal tooth right angled, infradental lamella thin, evenly and shallowly concave; first gastral tergite with four squamiform setae on posterior margin, two at mid-disk.

Queen

HW 0.51–0.53 (n=2); mandible and labrum similar to worker; face shape similar to worker but with large, shallow, circular concavity medial to compound eye, separated from eye by distinct slightly elevated carina that partially covers eye in full face view; compound eye longer than maximum width of scape; ocelli small, cuticle adjacent to ocelli marked with black pigment spots on evenly light brown background; shape of propodeal tooth, infradental lamella, petiole and postpetiole similar to worker; katepisternum and anepisternum large, convex, separated by thin groove; pubescence layer of abundant, short, curved setae covers mandible, face, scapes, legs, dorsal mesosoma and metasoma; abundant stiff erect setae on face, anterior edge of scape, side of head, dorsal mesosoma, dorsal gaster.

Fore wing: pterostigma placed about 3/5 the length of the costal margin; veins Sc+R, M+Cu, 1A, and crossvein 2rs-m tubular; 2rs-m terminating posteriorly as a node; veins Rs, M, and Cu nebulous; Rs+M spectral; vannal region vestigial; only basal and submarginal 1 cells enclosed by tubular or nebular veins. Hind wing: only veins C+Sc+R and 1A tubular, and only for a very short length of the remigium; veins Sc+R, M+Cu, R, Rs and crossvein 2rs-m nebulous; no cells are closed; vannal region vestigial.

Type Material

Holotype Specimen Labels

Holotype worker: Costa Rica, Heredia: La Selva Biological Station, 10.43333 -84.01667 ±1.5 km, 50 m, 1 Feb 1994, rainforest, ex Berlese of litter and soil (ALAS#B/05/381) Instituto Nacional de Biodiversidad, unique specimen identifier INBIOCRI001259541. Paratypes (workers): same data as holotype Los Angeles County Museum of Natural History, INBIOCRI001259538; Museum of Comparative Zoology, INBIOCRI001259539; National Museum of Natural History, INBIOCRI001259540; California Academy of Sciences, INBIOCRI001259542; same data but 15 Apr 1993 (ALAS#B/05/053) Escuela Agricola Panamericana, INBIOCRI002281441.

Etymology

Referring to the sparse spatulate setae on the gaster.

References

  • Longino J. T. and Boudinot B. E. 2013. New species of Central American Rhopalothrix Mayr, 1870 (Hymenoptera, Formicidae). Zootaxa. 3616:301-324. doi:10.11646/zootaxa.3616.4.1