Strumigenys ipsea

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

The few collections of this species have been from dense-forest litter samples.

Identification

Bolton (2000) - A member of the chroa complex in the Strumigenys scotti-group. S. ipsea is the only member of the chroa-complex that lacks a mandibular lamella, but is still easily recognized as belonging to this complex by the more or less straight mandibles. S. ipsea is distingui shed from other species in the chroa-complex by having the mesopleural gland set in a broad concave impression that extends along half of the anterior margin of the katepisternum and its large size, HL 0.79-0.83, HW 0.54-0.57. In addition, the following characters help identify this species: pronotal humeral hair flagellate or looped; mesonotum with only a single pair of erect hairs; spongiform appendages of petiole nearly absent.

Keys including this Species

Key to Malagasy Strumigenys

Distribution

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 ipsea. Worker. Specimen code casent0005561. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by MCZ, Cambridge, MA, USA.


Paratype of Strumigenys ipsea. Worker. Specimen code casent0005562. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by MCZ, Cambridge, MA, USA.


Holotype of Strumigenys ipsea. Worker. Specimen code casent0005563. 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.

ipsea. Strumigenys ipsea Fisher, in Bolton, 2000: 685 (w.) 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 3.4, HL 0.80, HW 0.52, CI 65, ML 0.44, MI SS, SL 0.58, SI 111, PW 0.31, AL 0.86. Characters of chroa-complex. Mandibles almost straight and at full closure parallel except at base; proximal preapical tooth slightly longer than the distal. Upper scrobe margin evenly and shallowly convex in full-face view, not bordered by a rim or flange, the eyes visible. Maximum diameter of eye distinctly greater than maximum width of scape, with 5-6 ommatidia in longest row. Scape long and slender, subcylindrical and only very feebly curved near the base; hairs on leading edge small and slender, slightly flattened or spoon-shaped apically. Cephalic dorsum clothed with curved narrow spatulate to spoon-shaped ground-pilosity, concentrated on anterior half of head; the upper scrobe margins fringed with a dense row of hairs which are the same shape and size as those on the dorsum. Cephalic dorsum with 6 simple standing hairs arranged in a transverse row of 4 close to the occipital margin and a more anteriorly situated pair. Pronotal humeral hair flagellate. Mesonotum with a single pair of standing hairs. Propodeum with one pair of short, posteriorly curved hairs immediately anterior of propodeal spines. Ground-pilosity on alitrunk as on head but the hairs smaller and sparser. Promesonotum convex; posterior portion of mesonotum shallowly depressed behind the level of the standing hairs. Anterior mesonotum with a narrow carina above the mesothoracic spiracle. Mesopleural gland set in a broad concave impression extending along half of the anterior margin of the katepistemum; in profile, maximum width of concave impression approximately equal to width of fore coxa. Propodeal tooth triangular, lamellate, pointed apically; lamella absent from declivity. Dorsal alitrunk reticulate-punctate. Sides of alitrunk superficially punctulate peripherally, the pleurae mostly smooth. Petiole node at least as long as broad, often longer than broad. Postpetiole disc mostly smooth, lateral margins longitudinally striolate and feebly punctate. Spongiform appendages of petiole nearly absent, with only a very narrow superficial ventral strip. Postpetiole with small ventral spongiform lobes. Basigastral costulae sparse and short. Dorsal surfaces of petiole, postpetiole and gaster with standing hairs which are simple or very slightly thickened apically. Colour yellowish brown to medium brown.

Paratypes. TL 3.4-3.5, HL 0.79-0.83, HW 0.54-0.57, CI 66-72, ML 0.42-0.43, MI 52-54, SL 0.57-0.62, SI 99-112, PW 0.34-0.37, AL 0.88-0.93 (5 measured). As holotype.

Type Material

Holotype worker, Madagascar: Provo Diego Suarez, Marojejy Mts, 29.xi.1972, 2060 m., dense forest #4052 (J. -M. Betsch) (Museum of Comparative Zoology).

Paratypes. 5 workers with same data as holotype (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 685, worker described)

References based on Global Ant Biodiversity Informatics

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.