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Species: Tetramorium dysalum   Bolton, 1979 

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Taxonomic History (provided by Barry Bolton, 2021)

Tetramorium dysalum Bolton, 1979 PDF: 141, fig. 24 (w.q.) MADAGASCAR. Malagasy. Primary type information: MADAGASCAR, Perinet and vicinity, rainforest, 17.III.1969, coll. W.L. Brown; CASENT0906148; MCZC AntCat AntWiki HOL

Taxonomic history

// Distribution


  Geographic regions (According to curated Geolocale/Taxon lists):
    Africa: Madagascar
  Biogeographic regions (According to curated Bioregion/Taxon lists):

Taxonomic Treatment (provided by Plazi)

Treatment Citation: Bolton, B., 1979, The ant tribe Tetramoriini (Hymenoptera: Formicidae). The genus Tetramorium Mayr in the Malagasy region and in the New World., Bulletin of the British Museum (Natural History) Entomology 38, pp. 129-181

Tetramorium dysalumHNS sp. n.

(Fig. 24)

Holotype worker. TL 3.1, HL 0 - 72, HW 0.71, CI 99, SL 0.50, SI 70, PW 0.52, AL 0.84.

Mandibles smooth and shining, unsculptured except for minute pits. Anterior clypeal margin with an impression or notch. Frontal carinae strong, surmounted by a narrow raised rim or flange. Alitrunk sharply marginate anteriorly and laterally, the margination of the sides interrupted at the promesonotal junction and more strongly impressed at the metanotal area, between mesonotum and propodeum. Pronotal dorsum transversely flat, the propodeal dorsum transversely feebly concave. Propodeum with a pair of long, acute spines which are slightly downcurved along their length. Metapleural lobes triangular. Node of petiole in profile high and quite narrow, the anterodorsal angle somewhat higher than the posterodorsal so that the slightly convex dorsal surface slopes downwards posteriorly. Dorsum of head regularly longitudinally rugulose, the interspaces with very feeble superficial ground-sculpture. Dorsal alitrunk strongly longitudinally rugose. Petiole and gaster unsculptured but dorsum of postpetiole with very faint traces of superficial sculpture. All dorsal surfaces of head and body with numerous elongate, fine hairs. Colour uniform brown.

Paratype workers. TL 2.7 - 3.1, HL 0.64 - 0.72, HW 0.60 - 0.71, CI 95 - 100, SL 0.43 - 0.50, SI 68 - 73, PW 0.46 - 0.52, AL 0.74 - 0.84 (15 measured).

As holotype but some specimens slightly darker in shade than the holotype, often the gaster lighter in shade than the alitrunk. The entire type-series apparently represents a single nest-sample, so the normal size variation in this species is fairly large. The degree of curvature of the propodeal spines varies, most specimens being as holotype but a few have them slightly more or slightly less downcurved.

Holotype worker, Madagascar: Perinet & vic, rain forest, 17. iii. 1969 (W. L. Brown) (MCZ, Cambridge). Paratypes. 39 workers and 1 dealate queen with same data as holotype but on some pins the lower label having ' rot. wood' or ' for. litter' (MCZ, Cambridge; BMNH).


Two series collected more recently by W. L. Brown in Madagascar: vic. Andasibe (= Perinet), 2 - 6. ii. 77, and Mangabe I.: Antongil Bay, 19. ii. 77, agree well with the above description but in the Andasibe series body hairs are darker in colour than in the type-series.

This species appears to be close to marginatumHNS, but in that species the dorsal alitrunk is unsculptured.

Specimen Habitat Summary

Found most commonly in these habitats: 46 times found in rainforest, 40 times found in montane rainforest, 5 times found in gallery forest, 2 times found in disturbed gallery montane forest, 1 times found in montane shrubland, 1 times found in rain for., 1 times found in in dry forest, 2 times found in in guava forest, 1 times found in mixed tropical forest, 1 times found in Dry forest on tsingy, ...

Found most commonly in these microhabitats: 33 times sifted litter (leaf mold, rotten wood), 18 times ex rotten log, 6 times sifted litter, 7 times ground forager(s), 2 times on low vegetation, 2 times ex soil, 1 times ex dead twig above ground, 1 times under root mat on rock, 1 times under root mat on live tree, 1 times under moss, above ground.

Collected most commonly using these methods: 19 times MW 50 sample transect, 5m, 6 times pitfall trap, PF 50 tube sample transect, 5m, 5 times MW 25 sample transect, 5m, 6 times pitfall trap, PF 50 traps, 11 cm dbh with water, soap, formalin, nonlinear placement, 6 times 10 MaxiWinks, mixed samples, 7 times Malaise trap, 1 times 10 maxi winks, 2 times MW 75 sample transect, 5,10m, 2 times pitfall trap, 2 times pitfall traps, 1 times 02 MaxiWinks, mixed samples, ...

Elevations: collected from 25 - 1657 meters, 921 meters average

Collect Date Range: collected between 1969-03-17 and 2017-01-12

Type specimens: Holotype of Tetramorium dysalum: casent0906148

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