Tetramorium tantillum

Tetramorium tantillum
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Crematogastrini
Genus:	Tetramorium
Species:	T. tantillum
Binomial name
Tetramorium tantillum Bolton, 1979 Specimen labels

This relatively large and conspicuous species is known only from a handful of sampling events from a few rainforest localities in Eastern Madagascar. This is surprising because the other species of the T. tosii group, Tetramorium tosii, is relatively common across nearly all of the rainforest zone of Eastern Madagascar. The more abundant T. tosii could have the ability to displace the morphologically close T. tantillum, although presently no evidence supports this theory. More than half of the specimens were collected from lower vegetation, implying that T. tantillum lives predominantly in this stratum; fewer specimens were collected on the ground, where this ant also may forage.

Identification

A member of the Tetramorium tosii species group

The antennal scapes of moderate length (SI 79 - 87) and the long propodeal spines (PSLI 30 - 33) render T. tantillum easily identifiable within the T. tosii species group. Tetramorium tantillum possesses distinctly shorter antennal scapes and propodeal spines than Tetramorium tosii (SI 97 - 104; PSLI 42 - 49). Also, the petiolar node shape is different, though this character should be considered with caution. Generally, the dorsum of the petiolar node of T. tantillum is less convex and the anterodorsal and posterodorsal angles are equally well-developed and of about the same height whereas the node of T. tosii shows a much more convex dorsum and the posterodorsal angle is always situated higher than the anterodorsal. However, some smaller specimens of T. tosii show a petiolar node shape that approaches the one viewed in T. tantillum.

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -16.67611111° to -23.20083333°.

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.

Nomenclature

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

• tantillum. Tetramorium tantillum Bolton, 1979: 152, figs. 30, 31 (w.) MADAGASCAR. See also: Hita Garcia & Fisher, 2011: 41.

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

Description

HL 1.010 - 1.080 (1.052); HW 0.900 - 0.970 (0.939); SL 0.750 - 0.810 (0.780); EL 0.180 - 0.205 (0.195); PW 0.695 - 0.720 (0.708); WL 1.294 - 1.338 (1.314); PSL 0.325 - 0.360 (0.343); PTL 0.345 - 0.370 (0.357); PTH 0.320 - 0.340 (0.327); PTW 0.350 - 0.380 (0.360); PPL 0.295 - 0.310 (0.303); PPH 0.330 - 0.350 (0.340); PPW 0.350 - 0.390 (0.371); CI 88 - 91 (89); SI 79 - 87 (83); OI 19 - 21 (21); PSLI 30 - 33 (33); PeNI 49 - 53 (51); LPeI 108 - 111 (109); DPeI 99 - 103 (101); PpNI 50 - 55 (52); LPpI 84 - 94 (89); DPpI 119 - 126 (123); PPI 99 - 107 (103) (5 measured).

Head distinctly longer than wide (CI 88 - 91). Anterior clypeal margin entire and convex. Frontal carinae well-developed, almost reaching posterior head margin. Antennal scrobes weakly developed, almost absent. Antennal scapes of moderate length, not reaching posterior margin of head (SI 79 - 87). Eyes relatively small (OI 19 - 21), with 11 to 13 ommatidia in longest row. Mesosomal profile relatively flat and only weakly convex, metanotal groove absent. Propodeal spines long, spinose, and acute (PSLI 30 - 33). Propodeal lobes triangular, short, and blunt. Node of petiole rectangular nodiform without sharp angles, in profile anterior and posterior faces roughly parallel, antero- and posterodorsal angles situated at about same height, dorsum moderately convex, node weakly longer than high (LPeI 108 - 111), in dorsal view roughly as long as wide (DPeI 99 - 103). Postpetiole in profile rounded, higher than long (LPpI 84 - 94), in dorsal view clearly wider than long (DPpI 119 - 126), as wide as petiolar node to weakly wider (PPI 99 - 107). Mandibles finely striate. Clypeus with 3 longitudinal rugae, median ruga more strongly developed. Head ventrally and laterally with distinct reticulate-rugose sculpturation, cephalic dorsum longitudinally rugose, with 6 to 8 rugae between frontal carinae; ground sculpturation on head weak and faint. Mesosoma and waist segments weakly reticulate-rugose without any distinct ground sculpturation. First gastral tergite completely unsculptured, smooth, and shiny. All dorsal surfaces of head, mesosoma, waist segments, and gaster with numerous long, standing hairs; hairs on antennal scapes and tibiae appressed. Colouration uniformly dark brown to blackish brown.

Type Material

Holotype worker, MADAGASCAR, Mangabe Island, Antongil Bay, 19.II.1977, primary rain forest, AB 42 litter, (W. L. & D. E. Brown) (Museum of Comparative Zoology) [not examined]. Paratypes, 3 workers with same data as holotype (MCZ, The Natural History Museum) [partly examined].

References

• Bolton, B. 1979. The ant tribe Tetramoriini (Hymenoptera: Formicidae). The genus Tetramorium Mayr in the Malagasy region and in the New World. Bull. Br. Mus. (Nat. Hist.) Entomol. 38: 129-181.
• Hita Garcia, F.; Fisher, B. L. 2011. The ant genus Tetramorium Mayr (Hymenoptera: Formicidae) in the Malagasy region—introduction, definition of species groups, and revision of the T. bicarinatum, T. obesum, T. sericeiventre and T. tosii species groups. Zootaxa 3039:1-72.

References based on Global Ant Biodiversity Informatics

• Fisher B. L. 1997. Biogeography and ecology of the ant fauna of Madagascar (Hymenoptera: Formicidae). Journal of Natural History 31: 269-302.
• 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.
• Hita Garcia F., and B. L. Fisher. 2011. The ant genus Tetramorium Mayr (Hymenoptera: Formicidae) in the Malagasy region—introduction, definition of species groups, and revision of the T. bicarinatum, T. obesum, T. sericeiventre and T. tosii species groups. Zootaxa 3039: 1-72.
• Hita García, F., and B. L. Fisher. "The ant genus Tetramorium Mayr (Hymenoptera: Formicidae) in the Malagasy region—taxonomy of the T. bessonii, T. bonibony, T. dysalum, T. marginatum, T. tsingy, and T. weitzeckeri species groups." Zootaxa 3365 (2012): 1-123.