Strumigenys lysis

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

The more than a dozen records of this species are primarily from montane forest and rainforest but there are also collections from a dwarf litoral forest and a park/garden. Most specimens have been found via litter sampling with a few being noted as coming from a rotten log, under a log and in a root mat.

Identification

Bolton (2000) - A member of the lysis complex in the Strumigenys arnoldi-group. S. lysis is easily separated from other members of the complex by the presence of a projecting laminar rim on upper scrobe margin throughout its length, a single pair of erect hairs on mesonotum, and the dorsolateral margin of the head posteriorly without 2-4 stiff erect hairs that are longer than hairs on leading edge of scape.

Keys including this Species

• Key to Malagasy Strumigenys

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -14.75° to -14.75°.

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

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. ‎

Castes

Worker

Images from AntWeb

Holotype of Strumigenys lysis. Worker. Specimen code casent0005597. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by MCZ, Cambridge, MA, USA.

Paratype of Strumigenys lysis. Worker. Specimen code casent0005598. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by CAS, San Francisco, CA, USA.

Paratype of Strumigenys lysis. Worker. Specimen code casent0005599. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by CAS, San Francisco, CA, USA.

Nomenclature

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

• lysis. Strumigenys lysis Fisher, in Bolton, 2000: 664 (w.q.) MADAGASCAR.

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 2.9, HL 0.70, HW 0.57, CI 81, ML 0.39, MI 56, SL 0.47, SI 83, PW 0.34, AL 0.73. Characters of lysis-complex. Each mandible with 2 preapical teeth, situated in the apical third; proximal preapical tooth longer than distal. Upper scrobe margin bordered by a narrow laminar rim. Eyes small, convex and plainly visible in full-face view; maximum diameter of eye subequal to maximum width of scape. Scape short, curved near base, widest in the midsection; hairs on leading edge fine, slightly flattened or spoon-shaped apically. Cephalic dorsum densely clothed with short curved narrowly spatulate to flattened scale-like ground-pilosity; upper scrobe margin fringed with curved narrowly spatulate hairs. Cephalic dorsum with 4 stout standing hairs arranged in a transverse row close to the occipital margin and a more anteriorly situated pair on vertex. Dorsum of head reticulate-punctate with superimposed rugulose sculpture on middorsum and occipital angles. Pronotal humeral hair stiffly filiform; humeral angles rounded. Anterior margin of mesonotum with a pair of stout filiform hairs. Propodeum with one pairs of short, fine, posteriorly curved hairs at anterior base of propodeal spines. Alitrunk dorsum with short curved filiform to narrowly spatulate ground-pilosity. Dorsum of alitrunk in outline convex anteriorly, posterior alitrunk more or less flat to gradually sloping down to declivity. Metanotal groove shallowly impressed. Anterior mesonotum without a distinct carina above the mesothoracic spiracle. Propodeal spines narrowly triangular, spongiform apex, subtended by a very narrow lamella on declivity. Pronotum densely punctate with longitudinally striolate to costulate sculpture. Remainder of dorsal alitrunk reticulate-punctate, but in some the striolate or costulate sculpture continues to the propodeum. Pleurae smooth and shiny with peripheral punctures. Petiole node in dorsal view about as broad as long. Postpetiole disc longitudinally striolate on a finely punctulate surface, but in some, the punctulate sculpture is absent or weak. In profile ventral spongiform tissue of petiolar peduncle a well developed strip along the base of the peduncle, depth of strip more or less equal to the width of the mandible blade when viewed in profile and slightly less than maximum width of eye. Ventral spongiform lobe of postpetiole moderately developed. Basigastral costulae short and distinct. Dorsal surface of petiole with one pair of anteriorly proj ecting narrowly remiform hairs; postpetiole and gaster with stout standing narrowly remiform hairs. Colour light to medium brown.

Paratypes. TL 2.8-3.0, HL 0.68-0.73, HW 0.54-0.60, CI 77-88, ML 0.37-0.40, MI 53-58, SL 0.45-0.51, SI 82-87, PW 0.32-0.36, AL 0.69-0.80 (9 measured). As holotype.

Measurements of this material extend the range shown by the type-series: HL 0.67-0.74, HW 0.53-0.60, CI 79-81, ML 0.35-0.40, MI 53-54, SL 0.45-0.49, SI 82-85 (2 measured).

Type Material

Holotype worker, Madagascar: 6.5 km. SSW Befingotra, Res. Anjanaharibe-Sud, 14°45'S, 49°30'E, 875 m., 19.x.1994, sifted litter (leaf mold rotten wood), rainforest #1070 (9)-14 (B. L. Fisher) (Museum of Comparative Zoology).

Paratypes. 9 workers and 1 queen (dealate) with same data as holotype but coded (3)-13, (6)-10, (8)-10, (10)-10, (29)-20, (37)-6. (The Natural History Museum, South African Museum).

References

• Fisher, B.L. 2000. The Malagasy fauna of Strumigenys. Pp. 612-696 in: Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 664, worker described)

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.