Hypoponera ignavia

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Hypoponera ignavia
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Hypoponera
Species: H. ignavia
Binomial name
Hypoponera ignavia
Bolton & Fisher, 2011

Hypoponera ignavia P casent0218463.jpg

Hypoponera ignavia D casent0218463.jpg

Specimen Label

Only known from a few collections.

Identification

Bolton and Fisher (2011) - Hypoponera ignavia is closely related to Hypoponera boerorum and Hypoponera spei, but contrasts with them as follows.

1 Sculpture on the disc of the second gastral tergite is much more superficial and diffuse in ignavia than in either boerorum or spei.

2 Setae on the dorsum of the first gastral tergite are short, more closely resembling boerorum than spei.

3 The subpetiolar process is low and ventrally rounded, again more closely resembling boerorum.

4 Dimensions of ignavia (HW, SL) are within the known range of spei, but its CI 78–81 is slightly lower than in spei or boerorum, which have a combined CI 82–89. Also, SI 89–94 of ignavia is slightly higher than in spei plus boerorum (SI 77–85). PeNI, HS and PeS of ignavia fall within the range of spei.

A member of the boerorum group.

Keys including this Species

Distribution

Known from South Africa and Zimbabwe.

Distribution based on Regional Taxon Lists

Afrotropical Region: South Africa, Zimbabwe (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Hypoponera inhabit and nest in leaf litter, the surface layer of soil, downed rotten wood, and soil around plant roots. Nests are typically found by turning objects on the ground, like downed wood and rocks, or through the ripping away of bark found on rotting downed wood or at the base of dead trees. Litter samples in tropical areas, especially in moist forested sites, often contain individuals of this genus. All Hypoponera are thought to be predators of small arthropods but published details about their diet are sparse. A lack of information about other aspects of their biology is also typical for most species.

The genus is most diverse in the tropics. Species found in higher latitudes tend to be more widespread, common and abundant than their tropical and subtropical congeners.

Castes

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • ignavia. Hypoponera ignavia Bolton & Fisher, 2011: 57, figs. 52-54 (w.q.) ZIMBABWE.

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

Each of the three specimens that make up the type-series of ignavia has differently developed eyes; the degree of development is associated with the overall size of the specimen. In the holotype (HW 0.71, SL 0.67) the eye is a featureless blister; in the MHNG paratype (HW 0.65, SL 0.60) it is a depigmented single ommatidium and in the BMNH paratype (HW 0.61, SL 0.54) it is entirely absent. The possibility that the holotype is an intercaste and not a true worker must be considered, because as well as being the largest specimen with the largest eye, it also has a faint vestige of a transverse suture on the mesopleuron, dividing the sclerite into anepisternum and katepisternum.

In a short series (one worker and two dealate queens) from the Drakensberg Mountains of South Africa, the worker appears to have a tiny, completely depigmented, vestigial eye spot, a rounded subpetiolar lobe, standing setae on the first gastral tergite that are sparse and elongate (as in Hypoponera spei), and punctulate sculpture on the second gastral tergite that is even more faint and diffuse than in the ignavia type-series, so that at low magnification the sclerite appears polished and almost smooth. The extremely reduced gastral sculpture is duplicated in the queens and is very different from the densely punctate sculpture seen in spei queens. Because of the very reduced gastral sculpture these specimens are tentatively incorporated in ignavia, until more material is assembled and the situation can be reviewed.

Description

Worker

Measurements: HL 0.78–0.88 (0.88), HW 0.61–0.71 (0.71), HS 0.695–0.795 (0.795), SL 0.54–0.67 (0.67), PrW 0.46–0.52 (0.52), WL 1.03–1.20 (1.20), HFL 0.59–0.73 (0.73), PeNL 0.21–0.25 (0.25), PeH 0.45–0.52 (0.52), PeNW 0.32–0.37 (0.37), PeS 0.327–0.380 (0.380) (4 measured). Indices: CI 78–83 (81), SI 87–94 (94), PeNI 67–71 (71), LPeI 45–49 (48), DPeI 140–155 (148).

Eyes variably developed, see discussion below. In full-face view apex of scape, when laid straight back from its insertion, reaches or very slightly exceeds the midpoint of the posterior margin; SL/HL 0.69–0.76. Reticulate-punctulate sculpture of cephalic dorsum fine and superficial, but dorsal head distinctly more densely sculptured than pronotal dorsum, which is almost smooth. Lateroventral areas of head weakly superficially punctate. Propodeal dorsum almost smooth, with only faint, widely spaced, minute punctulae. Mesonotal-mesopleural suture absent. Metanotal groove distinctly incised across dorsum of mesosoma; mesonotum with a defined posterior margin. Propodeal declivity separated from side by a blunt angle or a weak margination, without sharp carinae. Mesopleuron smooth and shining. Petiole in profile with the anterior and posterior faces of the node weakly convergent dorsally; node only very slightly longer just above the anterior tubercle than at the dorsum. Sternite of petiole in profile with a differentiated lobe that lacks sharp angles anteriorly or posteriorly. Anterior margin of subpetiolar process, near its base, with a conspicuous pit from which a sensory seta arises. Maximum width of first gastral tergite in dorsal view about equal to the width of the second tergite at its midlength. Base of cinctus of second gastral tergite with strong, conspicuous cross-ribs. Posttergite of second gastral segment, from posterior margin of cinctus to apex, broader than long. Punctures on disc of second gastral tergite superficial, minute and sparse; distances between punctures greater than diameters of punctures and the surface appearing glossy. With first gastral segment in profile its dorsum with scattered short standing setae (mostly lost from holotype but conspicuous in both paratypes). Full adult colour light brown.

Type Material

Holotype worker (top specimen of two on pin), Zimbabwe: Umtali, Melsetter, 1700 m., ii.1969 (R. Mussard) (Musee d'Histoire Naturelle Genève).

Paratypes. 2 workers with same data as holotype (MHNG, The Natural History Museum).

References

  • Bolton, B. & Fisher, B.L. 2011. Taxonomy of Afrotropical and West Palaearctic ants of the ponerine genus Hypoponera Santschi. Zootaxa 2843: 1-118. PDF