Tetramorium petiolatum

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Tetramorium petiolatum
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Tetramorium
Species group: bicarinatum
Species: T. petiolatum
Binomial name
Tetramorium petiolatum
Sheela & Narendran, 1998

Nothing is known about the biology of Tetramorium petiolatum.

Identification

A member of the T. bicarinatum species group.

Sheela and Narendran (1998) - This species comes close to Tetramorium pacificum in the following characters: HW > 0.65mm, SL > 0.55mm, head rugosoreticulate, colour dark brown, TI with basal costulae. But it differs from pacificum in that (1) in the shape of petiole node-in this new species postero-dorsal angle of petiole node a little above antero-dorsal but not much higher as in pacifium (2) eye larger in size than pacificum (0.18-0.21 in pacificum, 0.24 in new species) (3) cephalic index 100 (in pacificum 83-90) and scape index 67 (79-87 in pacificum).

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Oriental Region: India (type locality).

Distribution based on AntMaps

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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.
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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.
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Biology

Castes

Nomenclature

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

  • petiolatum. Tetramorium petiolatus Sheela & Narendran, 1998a: 41, figs. 13-16 (w.) INDIA.

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

Description

Worker

Holotype. Head finely reticulate including ventral side, on ventral side sculpture not strong as on dorsal side and becoming feeble towards mid ventral line; reticulation within scrobe smaller than those of remaining parts; mandibles smooth polished with hair pits, masticatory margin with three acute teeth at apex followed by two denticles and then a bare area at base; clypeus anterior margin medially indented and depressed, no flange, mid lobe with three median carinae which extend backwards up to middle of head and branched beyond posterior clypeal margin; median carina not extending up to anterior margin, weak sublateral carinae also present on clypeus; frontal area triangular, shallow; frontal carinae distinct extending up to occipital corners; scrobe shallow, eyes large, prominent, lateral, almost round, situated almost on mid line, a little upwards. Antennae 12-jointed, scape slender reaching just below occipital corners, flagellar segments 2-7 transverse, F8, subequal F1 and club elongate, club 3-jointed, thick, longer than remaining flagellar segments together (19:16), terminal club segment longer than preceding two together (10:9).

Thorax: finely reticulate, reticulations on dorsal surface large, spaces within reticulation smooth, neck of pronotum punctate; with a short median transverse carina, anteriorly broad, on pronotum, a slight depression just below anterior margin (excluding neck) anterolateral corners angulate, sutures absent, margin of mesometanotal junction constricted, propodeal spines erect, not cylindrical, somewhat prismatic, pointing backwards and outwards, extreme tip pointing upwards, its length about 3x distance between its bases, and 2.5x basal width; 1.7x length of peduncle of petiole; metapleural lobes acutely pointed at apex; fore coxae shagreened remaining parts of legs smooth; femora medially swollen, spurs on mid and hind tibiae slightly pectinate.

Abdomen: Peduncle of petiole weakly punctate, nodes reticulate, sculpture on postpetiole weaker than that on petiole; petiole quadrate, convex above, posterior face a little higher than anterior face; peduncle shorter than petiole node (6:10); node height and length subequal; anterior and posterior faces sub-parallel, postpetiole rounded, lower in a level than petiole, anterior face sloping, petiole dorsally longer than broad, postpetiole transverse. Gaster smooth .except few basigastral costulae, subglobose, first tergite covering more than 3/4 its length, anterior margin dorsoventrally with ridges.

Colour blackish brown, gaster darker than head and thorax; antennae, mandibles, legs, propodeal spines and apical margin of gastral tergites testaceous. Head, thorax, pedicel and abdomen with moderate amount of long and strong brownish yellow bristles, those on head and thorax, pedicel and abdomen with moderate amount of long and strong brownish yellow bristles, those on head and thorax erect, on pedicel suberect and on gaster subdecumbent; antennae and legs with abundant, short, decumbent hairs; femora with sparse long erect setae.

Total length-4mm; Head length-0.93mm; Head width-0.93mm; Cephalic index-100; Eye diameter-0.24mm; Scape length-0.62mm; Scape index-67; Pronotal width-0.64mm; Alitrunk length- 1.1mm.

Type Material

Holotype: Worker, India : Kerala, Muthanga, Sheela. S, 7.10.1995. (Department of Zoology, University of Calicut).

Etymology

The species name petiolatus indicates the peculiar shape of the petiole.

References

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