Tetramorium signatum Emery 1895
Creators: name: Mbanyana, Nokuthula
name: Garcia, Francisco Hita
name: Robertson, Hamish Gibson
name: Roux, Johannes Jacobus Le
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Formicidae
Tetramorium
Tetramorium signatum

description: Tetramorium signatum Emery, 1895
Figs 3E, 4A, 22, 24
Tetramorium solidum var. signatum Emery, 1895: 35 (included in Bolton 1980: 251).
Tetramorium solidum subsp. lugrubre Forel, 1910: 425 (included in Bolton 1980: 251).
Tetramorium solidum var. grootensis Forel, 1913: 118 (included in Bolton 1980: 251).
Tetramorium solidum var. tuckeri Arnold, 1926: 259 (included in Bolton 1980: 251).
Diagnosis
Tetramorium signatum is similar to T. rufescens and T. pogonion. Tetramorium pogonion is relatively smaller compared to the other two species with relatively larger eyes (OI> 30) and a different head shape (Fig. 3K). Tetramorium signatum and T. rufescens can be separated on basis of the sculpture pattern on the dorsum of mesosoma. In T. signatum, the dorsum of the mesosoma has distinct longitudinal or irregular rugulae (Fig. 4A), whereas in T. rufescens, the dorsum of the mesosoma has a dense reticulate punctation and sometimes with a few short faint longitudinal costulae (Fig. 4B).
Material examined
Type material
SOUTH AFRICA: syntype of Tetramorium solidum var. signatum Emery, 1895: 1 pinned worker, Western Cape, Matjiesfontein, E. Simon leg. (MSNG: CASENT0904841); syntypes of Tetramorium solidum var. grootensis Forel, 1913: 1 pinned queen, 1 pinned ♂, Eastern Cape, Willowmore, H. Brauns leg. (BMNH: CASENT0901188; MHNG: CASENT0909156).
ANGOLA: syntype of Tetramorium solidum subsp. lugrubre Forel, 1910: 1 pinned worker, Mossamedes, de Picard leg. (MHNG: CASENT0909157).
NAMIBIA: syntypes of Tetramorium solidum var. tuckeri Arnold, 1926: 1 pinned queen, 1 pinned worker, Brehdon, 20 Dec. 1915, R.W.E. Tucker leg. (BMNH: CASENT0901189; SAMC: SAM-ENT-0011762).
Other material
SOUTH AFRICA (262 pinned specimens): Northern Cape: Dreghorn, 26.85755° S, 20.78949° E, 862 m a.s.l., 17 Dec. 2007, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C019926); Dreghorn, 26.85755° S, 20.78949° E, 862 m a.s.l., 17 Dec. 2007, N. Mbanyana and H.G. Robertson leg. (SAM- HYM-C019927); Cullinan Farm, 26.34087° S, 22.61083° E, 977 m a.s.l., 19 Dec. 2007, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C019928 to SAM-HYM-C019932); Cullinan Farm, 26.34087° S, 22.61083° E, 977 m a.s.l., 19 Dec. 2007, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C019933 to SAM-HYM-C019937); Cullinan Farm, 26.85770° S, 20.78656° E, 855 m a.s.l., 17 Dec. 2007, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C019938); between Askham and Vansylsrus, 27.03322° S, 21.09746° E, 872 m a.s.l., 18 Dec. 2007, nest entrance with crater of soil around entrance, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C019939); Cullinan Farm, 26.33562° S, 22.61217° E, 962 m a.s.l., 17 Dec. 2007, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C019940); Cullinan Farm, 26.34087° S, 22.61083° E, 977 m a.s.l., 19 Dec. 2007, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C027128); Loeriesfontein (SAM-HYM-C019277); Loeriesfontein (SAM- HYM-C019283); Rietfontein Oos (SAM-HYM-C019284); road between Karsten Farms and Goodhouse, Kokerboom site, Klein Pella, 29.06211° S, 18.97985° E, 832 m a.s.l., 16 Dec. 2007, Gariep rocky desert with Kokerboom and Euphorbi a, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C019946, SAM- HYM-C019954); road between Karsten Farms and Goodhouse, Kokerboom site, Klein Pella, 29.03527° S, 18.97662° E, 678 m a.s.l., 16 Dec. 2007, east desert with large Eurphobia trees, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C019955); road between Karsten Farms and Goodhouse, Euphorbia site, Klein Pella, 29.03527° S, 18.97662° E, 678 m a.s.l., 16 Dec. 2007, east Gariep desert with large Euphorbia, soil around the entrance, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C019956); road from Klein Pella to Orange River, 28.95083° S, 18.199153° E, 449 m a.s.l., Gariep plain desert, 16 Dec. 2007, sandy soil with gravel, shallow soil, found foraging on ground, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C019957); Goegab Nature Reserve, Jul. 1998, U. Kruger leg. (SAM-HYM-C013303); Brandvlei, 30°31′ S, 20°29′ E, 28 May 1986, A.J. Prins leg. (SAM-HYM-C001716); Dreghorn near Chalets, 26.85770° S, 20.78656° E, 855 m a.s.l., 17 Dec. 2007 (SAM-HYM-C019904, SAM-HYM-C019905, SAM-HYM-C019907, SAM-HYM-C019921); Dreghorn, 26.85755° S, 20.78949° E, 862 m a.s.l., 17 Dec. 2007, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C019922, SAM-HYM-C019925); Hopetown, 4 km E of Hopetown, Hopetown Municipal Farm, 15 Feb. 1992, B. Chambers leg. (SAM-HYM-C010856); road between Karsten Farms and Goodhouse, 29.06211° S, 18.97985° E, 832 m a.s.l., 16 Dec. 2007, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C019868); Mokala National Park, Lilydale Lodge, 29.06377° S, 24.47202° E, 602 m a.s.l., 12 Jan. 2009, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C023331); Tankwa Karoo National Park, 32.17430° S, 19.97382° E, 602 m a.s.l., 7 Jan. 2009, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C023332, SAM-HYM-C023324); Mokala National Park, Lilydale Lodge, 29.06377° S, 24.47202° E, 602 m a.s.l., 12 Jan. 2009, N. Mbanyana and H.G. Robertson (SAM- HYM-C023310); Mokala National Park, 29.14467° S, 24.28437° E, 1185 m a.s.l., 12 Jan. 2009, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C023311); Kimberley (SAM-HYM-C004019); Melton Wold, 31.46626° S, 22.72004° E, 1332 m a.s.l., 9 Jan. 2009, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C023315, SAM-HYM-C023316); Tankwa Karoo National Park, 32.17430° S, 19.97382° E, 490 m a.s.l., 7 Jan. 2009, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C023317, SAM-HYM-C023318); Melton Wold, 31.46741° S, 22.721550° E, 1333 m a.s.l., 7 Jan. 2009, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C023320); Tankwa Karoo National Park, 32.17430° S, 19.97382° E, 602 m a.s.l., 7 Jan. 2009, N. Mbanyana and H.G. Robertson leg. (SAM- HYM-C023322, SAM-HYM-C023325, SAM-HYM-C023327, SAM-HYM-C023328); Dreghorn near Chalets, 26.85770° S, 20.78656° E, 855 m a.s.l., 17 Dec. 2007, nest in soil underground, nest entrance at base of grass tuft, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C024391); Kortkop Farm, near Strydenburg, 30°09′ S, 23°44′ E, 17 Jun. 1995, pitfall trap, Karoo vegetation, B. Chambers leg. (SAM- HYM-C008768); Tankwa Karoo National Park, 32.21512° S, 20.07671° E, 522 m a.s.l., 7 Jan. 2009, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C023321); Tankwa Karoo National Park, 32.24758° S, 20.09660° E, 490 m a.s.l., 7 Jan. 2009, N. Mbanyana and H.G. Robertson leg. (SAM- HYM-C023319); Tankwa Karoo National Park, 32.42325° S, 19.98843, 379 m a.s.l., 7 Jan. 2009, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C023326); Kalahari Gemsbok National Park, Gemsbokplain waterhole and dung, 26°09.1′ S, 20°31.8′ E, 935 m a.s.l., 21 Nov. 1997, M. Uhlig leg. (SAM-HYM-C011358); Namakwaland, Gamsberg 2009 transect v4 -s7-t1, 29.22153° S, 18.97957° E, 959 m a.s.l., hand collected, 5 Sep. 2009, P. Hawkes and J. Fisher leg. (CASC: CASENT0250961). – Western Cape: Ladismith (SAM-HYM-C019279); Onder-Downs (SAM-HYM-C019282); 33 km from Prince Albert Road on Leeu Gama Road, 32°56′ S, 21°59′ E, 10–19 Oct. 1996, T.E. Tshiguvho leg. (SAM-HYM-C009330); 40 km from Seekoegat on Prince Albert Road, 33°10′ S, 22°10′ E, 10–19 Oct. 1996, T.E. Tshiguvho leg. (SAM-HYM-C009331); 2 km from Prince Albert Road on Leeu Gamka road, 33°11′ S, 22°02′ E, 10–19 Oct. 1996, T.E. Tshiguvho leg. (SAM-HYM-C009332); Josephskraal, 33.04182° S, 20.72157° E, 896 m a.s.l., 16 Apr. 2008, Koedoesberge-Moordenaars Karoo, nesting in soil under rock, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C020573); Abrahamskraal, 32.92874° S, 22.00435° E, 522 m a.s.l., 12 Apr. 2008, drainage line with deep soils soft at about 20 cm and after that harder and compacted, nesting in soil under rock, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C020506, SAM-HYM-C020510, SAM-HYM-C020513); Abrahamskraal, 32.93011° S, 22.00949° E, 522 m a.s.l., 12 Apr. 2008, rocky ridges with sparsely distributed shrubs, shallow soil, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C020330, SAM-HYM-C020335, SAM- HYM-C020344); Gamkaskloof, 33°21′48″ S, 21°37′39″ E, 24 Oct. 2005, Nama Karoo rocky hillside, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C019028); Gamkaskloof, 33°21′48″ S, 21°37′39″ E, 25 Oct. 2005, Nama Karoo rocky hillside, N. Mbanyana and H.G. Robertson leg. (SAM- HYM-C019033); Vêrgenoeg, 33.24421° S, 21.47939° E, 670 m a.s.l., 10 Apr. 2008, Koedoesberge-Moordenaars Karoo, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C020400); Vêrgenoeg, 33.24467° S, 21.47597° E, 670 m a.s.l., 10 Apr. 2008, Koedoesberge-Moordenaars Karoo, east-facing rocky slope, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C020431); Josephskraal, 33.04182° S, 20.72157° E, 896 m a.s.l., 16 Apr. 2008, Koedoesberge-Moordenaars Karoo, found nesting in deep soil on elevated flood plain, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C020469, SAM- HYM-C020452); Vrede, Anysberg Nature Reserve, Karoo vegetation, 33°28′00″ S, 20°35′00″ E, 27 Feb. 1999, foraging in front of a bungalow, H.G. Robertson leg. (SAM-HYM-C013034); Vrede, Anysberg Nature Reserve, 33°28′00″ S, 20°35′00″ E, 27 Feb. 1999, Karoo vegetation, foraging on sandy soils near river (SAM-HYM-C013039); Prince Albert, Tierberg Research Station, 33.168833° S, 22.270111° E, 740 m a.s.l., 14 Feb. 2006, succulent Karoo, pitfall trap, Iimbovane Outreach Project, B. Braschler leg. (SAM-HYM-C024974); Vêrgenoeg, 33.23126° S, 21.46445° E, 630 m a.s.l., 10 Apr. 2008, Koedoesberge-Moordenaars Karoo, Karoo plain with succulent components mainly mesems (Aizoaceae), nest with at least 15 entrances covering about half a meter square, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C020539, SAM-HYM-C020546); Josephskraal, 33.04287° S, 20.7193° E, 900 m a.s.l., 16 Apr. 2008, Koedoesberge-Moordenaars Karoo, Karoo plain slightly N-facing, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C020436); Die Hell, Synamn Hut, 33°21′49″ S, 21°37′39″ E, 25 Oct. 2005, A. MacArthur leg. (SAM-HYM-C019522); Namakwa Sands, 31°16′14.1″ S, 17°56′23.7″ E, 31 Mar.–4 Apr. 2003, natural vegetation, Strandveld, pitfall traps, N. Ndivhuwo leg. (SAM-HYM-C018093, SAM-HYM-C018097). – Eastern Cape: Willowmore, 1 Jan. 1914, Rhodesia Museum (SAM-HYM-C004017); Willowmore, Oct. 1912, Dr H. Brauns leg. (SAM-HYM-C004018); 16 km N of Willowmore on Brakfontein Farm, 33°09′ S, 23°26′ E, sand, Karoo scrub, nesting on ground partly under rock, 5 Sep. 1988, H.G. Robertson leg. (SAM-HYM-C005328); Aberdeen, 27 May 1987, A.J.Prins andA. Roux leg.(SAM-HYM-C001686); Vanrhyns Pass, 24Aug.1963 (SAM-HYM-C004122); Brandkop, 22 Apr. 1963 (SAM-HYM-C004124); Blomplaas, 60 km SE of Aberdeen, 32°52′ S, 23°40′ E, 5 Sep. 1988, bare ground on Karoo scrub, nesting underground, H.G. Robertson leg. (SAM- HYM-C001317); 16 km N of Willowmore on Brakfontein Farm, 33°09′ S, 23°26′ E, 5 Sep. 1988, sand, Karoo scrub, nest partly under rock, partly underground, H.G. Robertson leg. (SAM-HYM-C001311).
NAMIBIA: 61.2 km S of Gobabis on C20, at intersection of C20 and D1790, 23°44.908′ S, 18°50.987′ E, 1246 m a.s.l., nesting in deep red-orange sandy soils, nest with a crater of soil around entrance, 17 Apr. 2011, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C027005); 31 km NW of Henties Bay on C35, 21°55.433′ S, 14°25.164′ E, nesting in loose gravely soil, entrance in open, 9 Apr. 2011, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C027007); Klein-Aus-Vista, 26°39.221′ S, 16°14.532′ E, 1325 m a.s.l., rocky N-facing slope with low shrubs and grass, soil shallow and gravelly, 5 Apr. 2011, N.Mbanyana and H.G.Robertson leg.(SAM-HYM-C027009); 157km from Gobabis on C20, 23°44.908′S, 18°50.987′ E, 17 Apr. 2011, entrance with crater of soil around, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C027011); Klein-Aus Vista, 26°39.198′ S, 16°14.542′ E, 1273 m a.s.l., 3 Apr. 2011, nest in rocky sand soil at base of dead grass tuft in middle of dry riverbed, entrance with crater of soil around it (SAM-HYM-C026892, SAM-HYM-C027012); Klein-Aus Vista, 26°39.143′ S, 16°14.546′ E, 1316 m a.s.l., 4 Apr.2011, nest in rocky sands, with about four entrances closer to each other with crater of soil around entrance (SAM-HYM-C027015); Marienfluss, Koakoveld, 17°23′38.4″ S, 12°29′59.2″ E, 15 Oct. 2008, M. Picker leg. (SAM-HYM-C023244); Kakamas, Orange River, National Museum of South Rhodesia leg. (SAM-HYM-C004019); Marienfluss, Koakoveld, 17°23′38.4″ S, 12°29′59.2″ E, 15 Oct. 2008, M. Picker leg. (SAM-HYM-C027002); Gamsberg, 29.22153° S, 18.97953° E, 929 m a.s.l., 15 Dec. 2007, P. Hawkes and J. Fisher leg. (SAM-HYM-C024382); Diamond Area 1, 27°17′ S, 15°58′ E, 2–3 Nov. 1986, pitfall traps, E. Griffin leg. (SAM-HYM-C027111); Keetmanshoop District, Khabus 146, 26°18′ S, 18°13′ E, on sandy plain next to dry riverbed, 14 Apr.–30 Jun. 1988, N. and G. Olivier leg. (SAM-HYM-C027177); Keetmanshoop District, Khabus 146, 26°17′ S, 18°14′ E, on dolerite hill, E slope, pitfall traps, 23 Jul.–1 Oct. 1988, N. and G. Olivier leg. (SAM-HYM-C027180); Diamond Area 1, 28°12′ S, 16°49′ E, 14–29 Sep. 1994, pitfall traps, E. Marais leg. (SAM-HYM-C027182); Klein Aus 10, Luderitz District, 26°38′ S, 16°10′ E, 12–26 Nov. 1993, E. Marais leg. (SAM-HYM-C027185); Keetmanshoop District, Khabus 146, 26°18′ S, 18°13′ E, on sandy plain next to riverbed, 14 Mar.– 14 Apr. 1988, N. and G. Olivier leg. (SAM-HYM-C027186, SAM-HYM-C027187); Diamond Area 1, 28°14′ S, 16°39′ E, 25–29 Sep. 1994, E. Marais leg. (SAM-HYM-C027189); Sendelingsdrift, Diamond Area 1, 28°07′ S, 16°50′ E, 14–29 Sep. 1994, E. Marais leg. (SAM-HYM-C027190); Askham and Vansylsrus, 27.03322° S, 21.09746° E, 872 m a.s.l., nest with crater of soil around entrance, 18 Dec. 2007, N. Mbanyana and H.G. Robertson leg. (SAM-HYM-C024392); Uniab Delta, 20.11° S, 13.12° E, collected from nest, 9Apr. 1987, J. Irish leg. (SAM-HYM-C001053); 40 km W of Aus Desert, 26°34.7′ S, 15°53.6′ E, 25 Nov. 1997, M. and B. Uhlig leg. (SAM-HYM-C011357); 9 mi. NW of Grunau, 4 May 1958, E.S. Ross and R.E. Leech leg. (CASC: CASENT0280906).
Measurements (worker N =47)
HL 0.885 –1.249 (1.092); HW 0.875 –1.219 (1.053); SL 0.708 –0.934 (0.808); EL 0.266 –0.344 (0.308); PH 0.393 –0.590 (0.488); PW 0.570 –0.816 (0.695); WL 0.944 –1.328 (1.139); PSL 0.079 –0.246 (0.179); PTH 0.285 –0.438 (0.348); PTL 0.246 –0.384 (0.319); PTW 0.275 –0.471 (0.356); PPH 0.295 –0.482 (0.377); PPL 0.226 –0.334 (0.279); PPW 0.315 –0.610 (0.437); OI 25–33 (29); CI 90–105 (96); SI 71–82 (77); DMI 55–81 (61); LMI 35–57 (43); PSLI 7–21 (16); PeNI 45–58 (51); LPeI 80–108 (92); DPeI 93–124 (112); PpNI 51–75 (63); LPpI 62–97 (74); DPpI 128–200 (157); PPI 106–132 (123).
Distribution
Known from South Africa and Namibia.
Remarks
The material examined matched mostly Bolton’s description, but a number of differences were noted. Interestingly, the colour variation in this species is explained by geographical distribution. It looks like there are two forms, the Karoo form and the Kalahari sand form. The specimens collected in the Karoo region mainly in South Africa are brown to black. The specimens collected from red sand dunes (Northern Cape, i.e., Dreghorn and Cullinan Farm, and parts of southern Namibia) are reddish. There is also variation in sculpture pattern. In black coloured specimens, the mesosoma has a strong irregular sculpture on the pronotum and short longitudinal striations on the mesonotum with a punctulate sculpture in between. The nodes have a punctulate sculpture overlain by irregular striations. The first gastral tergite is punctulate or shagreened at the base. Most of the reddish specimens have a strong, irregular sculpture on the pronotum and short longitudinal striations on the mesonotum with a punctulate sculpture in between. In a few specimens, the nodes are predominantly smooth with only reticulate sculpture. The spine length varies in all forms from medium, which are broad at the base, to very short. Based on that high degree of morphological variation, there is a possibility that there is more than one species within both T. signatum and T. rufescens. Nevertheless, this can only be properly addressed within a molecular phylogenetic framework, which is outside the scope of this study. We are hopeful to resolve this question in a future study addressing the evolutionary and biogeographical history of this group. This species has been recorded from South Africa (Eastern Cape, Western Cape and Northern Cape) and Namibia. It has been recorded from the following ecoregions: Albany Thickets, Kalahari Xeric Savanna, Kaokoveld Desert, Knysna-Amatole Montane Forests, Montane Fynbos and Renosterveld, Nama Karoo (including Koedoesberge-Moordenaars Karoo), Namib Desert, Namibian Savanna Woodlands and Succulent Karoo. This species nests in sandy to loamy soils, entrances sometimes with crater of soil around them. Alates were collected from nests in December. Two nests were found with Thysanura inquilines. This species has been collected by digging up nests and also from pitfall traps, yellow pan traps, tuna baits, sugar baits and cookie baits.
description: Published as part of Mbanyana, Nokuthula, Garcia, Francisco Hita, Robertson, Hamish Gibson & Roux, Johannes Jacobus Le, 2018, A taxonomic revision of seed harvester ants of the Tetramorium solidum group (Hymenoptera: Formicidae) in southern Africa, pp. 1-59 in European Journal of Taxonomy 454 on pages 48-51, DOI: 10.5852/ejt.2018.454, http://zenodo.org/record/3817358