Strumigenys mixta

Strumigenys mixta
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Strumigenys
Species group:	louisianae
Species:	S. mixta
Binomial name
Strumigenys mixta Brown, 1953 Specimen Labels

While some of the type material was taken from orchid plants in quarantine, suggesting this species is arboreal, collections since have been made from litter or ground sampling. These have been from a range of forest habitats. The native range is Central and northern South America, with introduced populations in Arizona, United States.

Identification

Bolton (2000) - A member of the Strumigenys louisianae-group. Immediately identified by its possession of fine flagellate hairs at all the positions mentioned. No other species of the group has this arrangement. One (Strumigenys dubitata) has no flagellate hairs at all and Strumigenys louisianae only has them at the humeral angles of the pronotum.

Keys including this Species

• Key to Neotropical and Nearctic Strumigenys
• Key to western Nearctic Strumigenys species

Distribution

Strumigenys mixta has a spotty a native range from Venezuela to southern Guatemala and was most likely introduced in the USA. It has been collected several times among ornamental, irrigated landscapes at the University of Arizona, Pima, Arizona, and in residential areas of Yuma and Phoenix (Booher, 2021).

Latitudinal Distribution Pattern

Latitudinal Range: 8.025° to 7.516666667°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: AntMaps

Distribution based on Regional Taxon Lists

Nearctic Region: United States.
Neotropical Region: Costa Rica, Guatemala (type locality), Honduras, Venezuela.

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Nomenclature

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

• mixta. Strumigenys mixta Brown, 1953e: 4 (w.) GUATEMALA. See also: Bolton, 2000: 526.

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

Description

Worker

Holotype worker: TL 2.32 mm., HL 0.54 mm., ML 0.31 ram., WL 0.54 ram., CI 83, MI 57.

Differs significantly from Strumigenys louisianae only in the following details:

(1) Inner mandibular border with an extra minute denticle slightly basad of the apical third of the ML.

(2) Pilosity decidedly narrower and less conspicuous, especially on the posterior cephalic dorsum. Paired, outstanding hairs, one on each lateral occipital border, each humeral angle and each side of the mesonotum are all finely flagelliform, whereas in S. louisianae, the lateral occipital and mesonotal hairs are stiff and spatulate towards their apices.

(3) Metanotal groove completely or very nearly completely obsolete; in profile from lateral view, the posterior alitruncal dorsum continuous in outline, not interrupted by the notch at the metanotal groove as in S. louisianae.

Color light ferrugineous yellow.

Paratypes. TL 2.14-2.49 mm., HL 0.51-0.59 mm., ML 0.28-0.32, WL 0.51-0.60, CI 80-84, MI 54-60. The Escuintla (type nest) series is made up of mostly smaller, yellow individuals, while that from San Jos contains, workers mostly in the upper part of the size range given and medium ferrugineous or deep burnt-orange in color. Means of dimensions, but not of proportions, differ slightly, but there is also an absolute overlap. The color difference is not considered taxonomically significant in the face of similar variation seen in many other dacetine species.

Bolton (2000) - TL 2.1-2.5, HL 0.51-0.59, HW 0.43-0.46, CI 80-84, ML 0.28-0.32, MI 54-60, PW 0.25-0.30, AL 0.51-0.60 (3 measured). Mandible with a minute inconspicuous denticle proximal to the preapical tooth , located on the upper inner margin just distal of its midlength. With head in profile postbuccal groove shallow and obtuse. Apicoscrobal hair finely flagellate. Cephalic dorsum with 2 pairs of short standing hairs, one close to occipital margin, the other close to highest point of vertex. Pronotal humeral hair elongate, fine and flagellate; mesonotal standing hairs flagellate. Ventral surface of petiole with a minute spongiform lobe at the extreme posteroventral angle below the node; when postpetiole flexed downward this lobe is concealed between the ventral lobes of the postpetiole.

Type Material

Holotype (USNM) one of 15 workers taken at Escuintla, Guatemala (W. M. Mann leg.). Paratypes: 14 workers from type nest series, same data as for holotype, and 5 workers from orchid plants (Cattleya bowringeana) shipped from San Jose, Guatemala and intercepted in U.S. Plant Quarantine at San Francisco, California (SF 20739 Supl.; 46-5348). Deposited in USNM and MCZ.

Bolton (2000) - Holotype and paratype workers, GUATEMALA: Escuintla, v.1924 (W. M. Mann); paratype workers, GUATEMALA: San Jose, 12.iv.1946, SF 20139 Supl., 46-5348 (intercepted by U.S. Plant Quarantine at San Francisco, California), in shipment of orchids (Cattleya bowringeana) (no collector's name) (National Museum of Natural History, Museum of Comparative Zoology, The Natural History Museum) [examined].

Etymology

The name mixta refers to the intermediate characters, seemingly linking S. louisianae and Strumigenys emeryi Mann, but also distinguishing this species from both.

References

• Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 526, catalogue)
• Booher, D.B. 2021. The ant genus Strumigenys Smith, 1860 (Hymenoptera: Formicidae) in western North America north of Mexico. Zootaxa 5061, 201–248 (doi:10.11646/zootaxa.5061.2.1).
• Brown, W. L., Jr. 1953e. Three new ants related to Strumigenys louisianae Roger. Psyche. 60:1-5. (page 4, worker described)
• Brown, W. L., Jr. 1962c. The neotropical species of the ant genus Strumigenys Fr. Smith: synopsis and keys to the species. Psyche. 69:238-267.

References based on Global Ant Biodiversity Informatics

• Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
• Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).