Strumigenys minuscula

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Strumigenys minuscula
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. minuscula
Binomial name
Strumigenys minuscula
(Kempf, 1962)

Strumigenys minuscula casent0281948 p 1 high.jpg

Strumigenys minuscula casent0281948 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Strumigenys minuscula.

Identification

Bolton (2000) - A member of the Strumigenys lilloana-group. When Kempf (1962) first described this small species he placed it in the splendens-group (then the genus Gymnomyrmex), but with some hesitation. In all splendens-group species the basal lamella of the mandible is very long and narrow, usually at least equal in length to the tooth row and sometimes longer, the alitrunk is long and low, and the petiole node is distinctly longer than broad in dorsal view. These characters definitely do not apply to minuscula which has a short high basal lamella, short compact alitrunk and a petiole node that is much broader than long. Direct comparison of the holotypes implies that minuscula is related to Strumigenys lilloana, with the common characterisation tabulated above. If this interpretation is correct it follows that the full-face heart-shaped head of lilloana is rather more specialised than that of minuscula, but the latter has specialised its antennomere count by reduction from 6 to 4.

Keys including this Species

Distribution

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

Strumigenys were once thought to be rare. The development and increased use of litter sampling methods has led to the discovery of a tremendous diversity of species. Many species are specialized predators (e.g. see Strumigenys membranifera and Strumigenys louisianae). Collembola (springtails) and other tiny soil arthropods are typically favored prey. Species with long linear mandibles employ trap-jaws to sieze their stalked prey (see Dacetine trap-jaws). Larvae feed directly on insect prey brought to them by workers. Trophallaxis is rarely practiced. Most species live in the soil, leaf litter, decaying wood or opportunistically move into inhabitable cavities on or under the soil. Colonies are small, typically less than 100 individuals but in some species many hundreds. Moist warm habitats and micro-habitats are preferred. A few better known tramp and otherwise widely ranging species tolerate drier conditions. Foraging is often in the leaf litter and humus. Workers of many species rarely venture above ground or into exposed, open areas. Individuals are typically small, slow moving and cryptic in coloration. When disturbed individuals freeze and remain motionless. Males are not known for a large majority of species.

Castes

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • minuscula. Gymnomyrmex minusculus Kempf, 1962b: 24, figs. 22-24 (w.) BRAZIL. Combination in Pyramica: Bolton, 1999: 1672; in Strumigenys: Baroni Urbani & De Andrade, 2007: 124. See also: Bolton, 2000: 202.

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

Description

Worker

Bolton (2000) - TL 1.6, HL 0.43, HW 0.39, CI 91, ML 0.09, MI 22, SL 0.16, SI 41, PW 0.24, AL 0.43. This very small species is currently one of only two known Neotropical species with 4 antennal segments (the other is simulans). Extreme anterior portion of preocular carina visible in full-face view. Also in this view the head with the upper scrobe margin markedly sinuate: margin shallowly concave behind level of frontal lobe, expanding latterally behind level of second fenestra into a bluntly convex lobe, then becoming concave again until close to the scrobe apex where it again becomes convex and grades into the lateral margin of the occipital lobe. Eye with only 4 ommatidia in total. Dorsum of head hairless except for minute scattered appressed pubescence that is difficult to see. Dorsolateral margination of pronotum, and pronotal dorsum, hairless behind humeral angles; mesonotum with a single pair of short erect hairs. Dorsal surfaces of waist Segments and gaster with a number of short erect simple hairs. Sculpture absent except for basigastral costulae that arise across the entire width of the sc1erite. In dorsal view the lateral lobes of both the petiole and postpetiole are laminate rather than spongiform; in profile the ventral lobes of both segments are spongiform.

Type Material

Bolton (2000) - Holotype worker, BRAZIL: Santa Catarina, Chapeco, vii.1960 (F. Plaumann) (Museu de Zoologia da Universidade de Sao Paulo) [examined].

References

  • Baroni Urbani, C. & De Andrade, M.L. 2007. The ant tribe Dacetini: limits and constituent genera, with descriptions of new species. Annali del Museo Civico di Storia Naturale “G. Doria” 99: 1-191.
  • Bolton, B. 1999. Ant genera of the tribe Dacetonini (Hymenoptera: Formicidae). J. Nat. Hist. 3 33: 1639-1689 (page 1672, Combination in Pyramica)
  • Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 202, redescription of worker)
  • Kempf, W. W. 1962b. Miscellaneous studies on neotropical ants. II. (Hymenoptera, Formicidae). Stud. Entomol. 5: 1-38 (page 24, figs. 22-24 worker described)
  • Kempf, W. W. 1972b. Catálogo abreviado das formigas da regia~o Neotropical. Stud. Entomol. 15: 3-344 (page 116, catalogue)

References based on Global Ant Biodiversity Informatics

  • Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
  • Favretto M. A., E. Bortolon dos Santos, and C. J. Geuster. 2013. Entomofauna from West of Santa Catarina State, South of Brazil. EntomoBrasilis 6 (1): 42-63.
  • Kempf W. W. 1962. Miscellaneous studies on neotropical ants. II. (Hymenoptera, Formicidae). Studia Entomologica 5: 1-38.
  • Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
  • Rosa da Silva R. 1999. Formigas (Hymenoptera: Formicidae) do oeste de Santa Catarina: historico das coletas e lista atualizada das especies do Estado de Santa Catarina. Biotemas 12(2): 75-100.
  • Silva T. S. R., and R. M. Feitosa. 2019. Using controlled vocabularies in anatomical terminology: A case study with Strumigenys (Hymenoptera: Formicidae). Arthropod Structure and Development 52: 1-26.
  • Ulyssea M. A., C. R. F. Brandao. 2013. Catalogue of Dacetini and Solenopsidini ant type specimens (Hymenoptera, Formicidae, Myrmicinae) deposited in the Museu de Zoologia da Universidade de Sao Paulo, Brazil. Papies Avulsos de Zoologia 53(14): 187-209.