Lachnomyrmex scrobiculatus

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Lachnomyrmex scrobiculatus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Lachnomyrmex
Species: L. scrobiculatus
Binomial name
Lachnomyrmex scrobiculatus
Wheeler, W.M., 1910

Lachnomyrmex scrobiculatus casent0103243 profile 1.jpg

Lachnomyrmex scrobiculatus casent0103243 dorsal 1.jpg

Specimen labels

Lachnomyrmex scrobiculatus is a relatively common species. Workers and gynes occur in samples of sifted leaf litter from the forest floor in different elevations (100–1100m). Michael Kaspari collected a specimen at a barley bait in the La Selva successional plots, Costa Rica (Longino 2007).

Identification

Feitosa and Brandão (2008) - Body densely covered by continuous irregular rugae; metanotal groove obsolete; teeth of propodeal lobes widen basally; petiolar node subtriangular; dorsum of postpetiole convex and strongly rugose; first tergite of gaster entirely covered by long flexuous hairs.

This species is uniquely characterized by the pattern of sculpturation, absence of an impressed metanotal groove, and the presence of the small subpostpetiolar process. Gynes are somewhat more generalized morphologically (see Lachnomyrmex pilosus).

Keys including this Species

Distribution

Southern Mexico (Chiapas) throughout continental Central America to southern Panama.

Distribution based on Regional Taxon Lists

Neotropical Region: Belize, Costa Rica, Ecuador, Guatemala (type locality), Honduras, Mexico, Panama.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Very little is known about the biology of these cryptic ants. Workers are frequently found in leaf litter and soil samples processed in Winklers or Berlese extractors, but these ants are never especially abundant within samples. When a dealate gyne is found associated with workers in 1m2 samples of leaf litter, normally it is found singly, which suggests that colonies are relatively small and apparently monogynic; workers and nests are extremely difficult to spot in the field, because the workers are very slow moving and well camouflaged; if there is any leaf-litter nest structure, it is destroyed during sifting, but our impression is that they do not construct any permanent nidal structure. Species of Lachnomyrmex apparently nest within the leaf litter, inside natural cavities of the superficial soil layers, fallen logs, and rotten wood, as evidenced by the large number of soil-covered individuals collected, from information recorded in specimen label data, and from observations of collectors. Workers forage alone, in the leaf litter and in the low vegetation, occasionally among epiphytes and moss, probably preying on small soft-bodied arthropods and possibly harvesting plant exudates. (Feitosa and Brandao 2008)

Castes

Nomenclature

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

  • scrobiculatus. Lachnomyrmex scrobiculatus Wheeler, W.M. 1910a: 263, fig. 3 (w.q.) GUATEMALA. Wheeler, G.C & Wheeler, J. 1989a: 321 (l.). See also: Feitosa & Brandão, 2008: 40.

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

Description

Worker

Feitosa and Brandão (2008) - Lectotype worker. HL 0.65; HW 0.61; ML 0.17; SL 0.38; EL 0.12; WL 0.75; PSL 0.19; PL 0.33; PPL 0.16; GL 0.80; TL 2.86; CI 95; SI 61; OI 19. Workers (n=18). HL 0.60–0.66; HW 0.58–0.65; ML 0.17–0.22; SL 0.36–0.40; EL 0.12– 0.15; WL 0.69–0.76; PSL 0.14–0.19; PL 0.27–0.33; PPL 0.14–0.18; GL 0.74–0.87; TL 2.80–2.99; CI 95–100; SI 58–64; OI 19–24.

Color dark brown to black, with appendages lighter. Body densely covered by vermiculate and somewhat thick rugae, transverse on anterior portion of pronotum, grading to longitudinal on rest of promesonotum, metapleura and lateral faces of propodeum; rugae somewhat longer and longitudinal on head dorsum and relatively sparser on metapleura and lateral faces of propodeum; mandibles with short striae restricted to the most basal portion; in dorsal view, metanotal area with long transversal rugae extending laterally towards metapleura; petiole and postpetiole irregularly rugose. Abundant pilosity, except by dorsal surface of propodeum; petiolar node, dorsum of postpetiole and first gastral tergite covered by long flexuous hairs; pilosity on first tergite of gaster concentrated at the most dorsal portion.

Head usually slightly longer than broad, with vertexal margin minimally convex; frontal lobes relatively well developed and laterally rounded; eyes with about six facets on maximum diameter. Promesonotum moderately convex in profile; metanotal groove obsolete; propodeal spines straight; teeth of propodeal lobes well developed and considerably swollen basally, reaching propodeal spines half-length. Petiolar node elevated and subtriangular, in lateral view; postpetiole strongly convex and with a discrete anteroventral projection.

Queen

Feitosa and Brandão (2008) - (n=5). HL 0.66–0.68; HW 0.65–0.66; ML 0.22–0.24; SL 0.38–0.42; EL 0.16–0.19; WL 0.87–0.88; PSL 0.17–0.20; PL 0.31–0.33; PPL 0.17–0.20; GL 0.96–1.10; TL 3.23–3.36; CI 96–99; SI 57–65; OI 24–29.

Similar to worker; body pilosity considerably denser; eyes with about 12 facets at greatest diameter; wings with the basic pattern of venation for the genus; petiolar peduncle somewhat elongate; petiolar node faintly lower than in the conspecific worker.

Etymology

Feitosa and Brandão (2008) - The species name refers to the presence of the deep antennal scrobes, observed by Wheeler (1910) in the original description of Lachnomyrmex.

References

  • Feitosa, R.M. & Brandão, C.R.F. 2008. A taxonomic revision of the Neotropical myrmicine ant genus Lachnomyrmex Wheeler (Hymenoptera: Formicidae). Zootaxa 1890, 1-49.
  • Wheeler, G. C.; Wheeler, J. 1989a [1988]. Notes on ant larvae: Myrmicinae. Trans. Am. Entomol. Soc. 114: 319-327 (page 321, larva described)
  • Wheeler, W. M. 1910d. Three new genera of myrmicine ants from tropical America. Bull. Am. Mus. Nat. Hist. 28: 259-265 (page 263, fig. 3 worker, queen described)