Strumigenys ambatrix

Strumigenys ambatrix
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Strumigenys
Species:	S. ambatrix
Binomial name
	Strumigenys ambatrix; (Bolton, 2000) Specimen labels

Occurs in a range of forest habitats and has been collected from numerous litter samples in eastern Madagascar.

Identification

Bolton (2000) - A member of the Strumigenys rostrata-group. Of the four species of this group found in Madagascar ambatrix is unique in possessing long flagellate hairs at the pronotal humeri. In the other three species the humeral hairs are simple and straight or only very shallowly curved .

Keys including this Species

Key to Malagasy Strumigenys (as Pyramica)

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -15.66667° to -15.66667°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Malagasy Region: Madagascar (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

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.

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Castes

Worker

Images from AntWeb


Paratype of Strumigenys ambatrix. Worker. Specimen code casent0005446. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by CAS, San Francisco, CA, USA.


Paratype of Strumigenys ambatrix. Worker. Specimen code casent0005447. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by CAS, San Francisco, CA, USA.


Holotype of Pyramica ambatrix. Worker. Specimen code casent0005990. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by MCZ, Cambridge, MA, USA.

Nomenclature

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

ambatrix. Pyramica ambatrix Bolton, 2000: 255 (w.q.) MADAGASCAR. Combination in Strumigenys: Baroni Urbani & De Andrade, 2007: 115

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

Description

Worker

Holotype. TL 2.1, HL 0.56, HW 0.41, CI 73, ML 0.10, MI 18, SL 0.28, SI 68, PW 0.26, AL 0.60. Closely related to Strumigenys victrix and mostly matching the description given there, but differing as follows.

1 Pronotal humeral hair long and flagellate.

2 Mesonotum usually with 2 pairs of erect hairs.

3 Entire dorsal alitrunk, and propodeal declivity, densely sharply reticulate-punctate.

4 Ventral spongiform curtain of petiole extends the length of the segment, present beneath the peduncle but narrower there than beneath the node.

5 In dorsal view the postpetiole disc , from the posterolateral angles to the anterolateral angles, margined by spongiform tissue.

Paratypes. TL 2.0-2.1, HL 0.50-0.56, HW 0.40-0.42, CI 73-76, ML 0.09-0.11, MI 17-20, SL 0.26-0.28, SI 65-70, PW 0.24-0.28, AL 0.56-0.62 (10 measured). As holotype but number of mesonotal standing hairs apparently variable or affected by abrasion, with one or two pairs present.

Type Material

Holotype worker, Madagascar: 5.3 k m . SSE Ambanizana, Andranobe, 15°40'S, 49°58'E , 425 m., 21.xi.1993, sifted litter (leaf mold, rotten wood) rainforest, #926 (41)-1 (B.L. Fisher) (Museum of Comparative Zoology).

Paratypes. 1 worker and 1 queen (dealate) with same data as holotype; 20 workers and 4 queens (dealate) with same data but coded (2)-1 , (22)-2, (24)-1 , (25)-1 , (31)-1, (36)-1, (40)-1, (43)-1, (50)-1, (L.O.)-1 (University of California, Davis, The Natural History Museum).

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. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 355, worker described)
Tang, K. L., Guénard, B. 2023. Further additions to the knowledge of Strumigenys (Formicidae: Myrmicinae) within South East Asia, with the descriptions of 20 new species. European Journal of Taxonomy 907, 1–144 (doi:10.5852/ejt.2023.907.2327).

References based on Global Ant Biodiversity Informatics

Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
Fisher B. L. 2003. Formicidae, ants. Pp. 811-819 in: Goodman, S. M.; Benstead, J. P. (eds.) 2003. The natural history of Madagascar. Chicago: University of Chicago Press, xxi + 1709 pp.