Strumigenys xoko

Strumigenys xoko
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Strumigenys
Species group:	schulzi
Species:	S. xoko
Binomial name
Strumigenys xoko Santos-Neto, Chaul & Delabie, 2024

Little can be inferred about the biology of this ant based on the available material. The holotype was collected at the base of an Aechmea bromeliad, suggesting that, like other species within the schulzi species group, this ant prefers nesting in contact with plants.

Photo Gallery

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  Santos-Neto et al. (2024), Fig. 5. Strumigenys xoko. Holotype worker, head in full-face view (A), lateral view (B), gaster in dorsal with basigastral costulae in detail (C), dorsal view (D), [CPDC 5871], [ANTWEB1048665]. Scale bars are 0.2 mm.
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  Santos-Neto et al. (2024), Fig. 6. Strumigenys xoko. Paratype, queen, head in full-face view (A), lateral view (B), gaster in dorsal with basigastral costulae in detail (C), dorsal view (D), [CPDC5780] [ANTWEB1048666]. Scale bars are 0.2 mm.

Identification

With the following characters:

• basal lamella of mandible triangular, without diastema between it and masticatory margin
• eyes large, with 20 ommatidia in total
• broad flattened scapes
• stand pilosity narrowly remiform, ground pilosity of spatulate setae
• petiole and postpetiole entirely reticulate-punctate in dorsal view
• first gastral tergite entirely thinly striated
• basigastral costulae shorter than a third of postpetiole disc length

The dentition pattern of S. xoko looks like Strumigenys schulzi, Strumigenys castanea, Strumigenys orchibia and Strumigenys metrix. S. xoko can be easily identified because, among similar species, it is the only one that has first gastral tergite entirely striated (Figure 4C, Table 1).

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  Santos-Neto et al. (2024), Fig. 8. Profile view showing the difference in pilosity on the head and mesonotum of Strumigenys itannae. (A) and Strumigenys xoko (B).
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  Santos-Neto et al. (2024), Fig. 9. Profile view showing the difference in sculpture and basigastral costulae on first gastral tergite of Strumigenys xoko. (A, B) Strumigenys orchibia [BMNH1013600].

Diagnostic character matrix for species in the S. schulzi group (Santos-Neto et al. (2024), Table 1).

Species	Vertex with abundant erect setae	Pronotal humeral pair of stand setae shape	Lower mesopleuron smooth patch	Mesonotal stand setae number	Petiole node	Basigastral costulae	First gastral tergite
Strumigenys castanea	absent	remiform	absent	one pair	broader than long	thick, short and uniform	smooth
Strumigenys itannae	present	filiform	absent	two or three pairs	longer than broad	thick, short and uniform	smooth
Strumigenys metrix	absent	remiform	present	two or three pairs	longer than broad	thick, short and uniform	smooth
Strumigenys orchibia	absent	remiform	absent	one pair	broader than long	fine, dense and very long	smooth
Strumigenys schulzi	absent	remiform	absent	one pair	longer than broad	thick, short and uniform	smooth
Strumigenys xoko	absent	filiform	absent	two or three pairs	longer than broad	thick, short and uniform	finely striated

Keys including this Species

• Key to Neotropical Strumigenys (as Pyramica)

Distribution

Brazil (Bahia and Sergipe)

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  Santos-Neto et al. (2024), Fig. 2. Distribution of the new species and new records for previously described species of the schulzi group.

Latitudinal Distribution Pattern

Latitudinal Range: 14.6° to -9.6°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: Santos-Neto, Chaul & Delabie, 2024

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (type locality).

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.

Biology

Expand Explore Overview of Strumigenys 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. ‎

Nomenclature

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

• xoko. Strumigenys xoko Santos-Neto, Chaul & Delabie, 2024: 641, figs 4, 5 (w.q.) BRAZIL.

Type Material

• Holotype worker: BRAZIL, Sergipe: Canindé do São Francisco, −9.635367, −37.792324, 25.v.1997, Collected from Aechmea aquilega (Bispo, S.M.) [CPDC 5871, ANTWEB1048665].
• Paratype queen, BRAZIL, Bahia: Iguaí, 14.643.056, −40.147.778, 04.vii.2012 (C. Leite & T. Porto et al.) [CPDC 5780, ANTWEB1048666].

References

• Santos-Neto, E.A., Chaul, J.C.M., Delabie, J.H.C. 2024. New species and new records of Strumigenys Smith, 1860 (Formicidae: Myrmicinae) from the Neotropical schulzi species group. Taxonomy 4(3), 633–648 (doi:10.3390/taxonomy4030032)