Tetramorium malagasy Hita Garcia & Fisher, 2012

Garcia, Francisco Hita & Fisher, Brian L., 2012, 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, pp. 1-123 : 18-21

Tetramorium malagasy Hita Garcia & Fisher sp. n.

(figs 2, 8, 9, 17, 18, 19)

Holotype worker, MADAGASCAR, Toliara, Forêt de Mite , 20.7 km 29° WNW Tongobory, 23.52417 S, 44.12133 E, 75 m, gallery forest, ex rotten log, BLF5905, 27.II.-3.III.2002 (B.L. Fisher et al.) ( CASC: CASENT0449550 ) . Paratypes, eight workers with same data as holotype ( BMNH: CASENT0449549 ; CASC: CASENT0449540 ; CASENT0449541; CASENT0449542; CASENT0449543; CASENT0449544; CASENT0449545; CASENT04495 47; CASENT0449548) ; 27 workers with same data as holotype but collection code BLF5850 ( CASC: CASENT0018397 ; CASENT0018732; CASENT0018738; CASENT0018740; CASENT0018748; CASENT001 9010; CASENT0019013; CASENT0019016; CASENT0019018; CASENT0019024; CASENT0019027; CASENT 0019028; CASENT0019031; CASENT0019036; CASENT0019038; CASENT0019051;CASENT0019040; CASE NT0019044; CASENT0019053; CASENT0019056; CASENT0019057; CASENT0019061; CASENT0019064; CASENT0019066; CASENT0019076; MCZ: CASENT0018734 ; NHMB: CASENT0018736 ); and four workers with same data as holotype but collection code BLF5961 ( CASC: CASENT0004095 ; CASENT0004098; CASENT0004104; MHNG: CASENT0004141 ) .

Diagnosis

The following combination of characters distinguishes T. malagasy from the other species group members: short antennal scapes (SI 71–74); PSLI 33–37; absence of promesonotal suture; petiolar node in profile high nodiform, anterior and posterior faces approximately parallel, anterodorsal and posterodorsal angles at about same height, dorsum well-developed and not tapering backwards posteriorly; standing hairs absent from waist segments and first gastral tergite; and pubescence on first gastral tergite very short and appressed.

Description

HL 0.76–0.85 (0.82); HW 0.76–0.87 (0.82); SL 0.56–0.62 (0.60); EL 0.16–0.20 (0.18); PH 0.43–0.49 (0.46); PW 0.56–0.63 (0.60); WL 1.01–1.13 (1.07); PSL 0.25–0.31 (0.28); PTL 0.17–0.20 (0.19); PTH 0.31–0.34 (0.33); PTW 0.27–0.32 (0.29); PPL 0.22–0.25 (0.24); PPH 0.30–0.36 (0.33); PPW 0.32–0.37 (0.35); CI 100–102 (101); SI 71– 74 (73); OI 20–24 (22); DMI 54–58 (56); LMI 42–45 (43); PSLI 33–37 (34); PeNI 45–51 (48); LPeI 51–63 (57); DPeI 147–165 (155); PpNI 52–61 (57); LPpI 68–75 (72); DPpI 138–152 (145); PPI 112–129 (120) (15 measured). Head generally wider than long (CI 100–102). Anterior clypeal margin with distinct median impression. Frontal carinae well-developed, becoming weaker shortly after level of posterior eye margin and fading out shortly before posterior head margin. Antennal scrobes faint to absent, posterior and ventral margins never differentiated. Antennal scapes short, not reaching posterior head margin (SI 71–74). Eyes small to moderate (OI 20–24). Mesosomal outline in profile convex, dorsally transversely rounded, weakly to moderately marginate from lateral to dorsal mesosoma; promesonotal suture absent, metanotal groove weak but present; mesosoma comparatively stout (LMI 42–45). Propodeal spines long, spinose, and acute (PSLI 33–37). Propodeal lobes very small and broadly triangular. Petiolar node high nodiform, anterior and posterior faces approximately parallel, anterodorsal and posterodorsal angles at about same height, dorsum not tapering backwards posteriorly; node in dorsal view not strongly transverse, between 1.4 to 1.7 times wider than long (DPeI 147–165), in lateral view between 1.6 to 2 times higher than long (LPeI 51–63). Postpetiole in profile rounded and weakly anteroposteriorly compressed, approximately 1.3 to 1.5 times higher than long (LPpI 68–75), in dorsal view between 1.3 to 1.6 wider than long (DPpI 138–152). Postpetiole in profile less voluminous than petiolar node, in dorsal view approximately 1.1 to 1.3 times wider than petiolar node (PPI 112–129). Mandibles distinctly longitudinally striate; clypeus always with strong median longitudinal ruga and one or two weaker rugulae at each side; cephalic dorsum between frontal carinae only with one well-developed longitudinal median ruga, median ruga diverging approximately at eye level into two rugae running to posterior clypeal margin, area between median ruga and frontal carinae often unsculptured or with traces of weak rugulae, median ruga of same length as frontal carinae; scrobal area, lateral and ventral head with irregular longitudinal rugulae, anteriorly more reticulate-rugose and posteriorly more weakly developed. Ground sculpture generally weak, but present. Mesosoma, waist segments, and gaster unsculptured and smooth. Ground sculpture on whole body generally faint. Head with several long, standing hairs, mesosoma often without any pilosity, mesonotum sometimes with one pair of hairs, waist segments and first gastral tergite always without any standing hairs; whole body with widely spaced short, appressed pubescence. Whole body of uniform brownish colour.

Notes

The new species is widely distributed in Madagascar, and seems to prefer deciduous forest habitats, such as tropical dry forest, gallery forest, spiny forest or thicket, whereas it is much rarer in humid forests. It occurs in many localities at the western coast from the Mahafaly Plateau north to Namoroka, and several more in the southwest from Beza-Mahafaly through Sakaraha and Zombitse to Vohibasia, Analalava, and Isalo. Tetramorium malagasy is also present in the southeast around Mahavelo and Berenty, and several forests in the east north to Moramanga. However, it seems to be comparatively rare north of Moramanga in the east and Namoroka in the west since it was only sampled from three localities in the northwest (Anabohazo, Ambilanivy, Ambato).

Tetramorium malagasy cannot be confused with the three species T. artemis , T. bessonii , and T. wardi since they all display a squamiform, anteroposteriorly compressed petiolar node with an anterodorsal margin that is situated higher than the posterodorsal margin, causing the dorsum to taper backwards posteriorly. This shape contrasts with the petiolar node of T. malagasy , which is high nodiform with anterior and posterior faces approximately parallel and anterodorsal and posterodorsal angles at about the same height. The two remaining species, T. orientale and T. ryanphelanae , share the same node shape with T. malagasy , and are all morphologically close to each other. However, T. orientale possesses a well-developed and conspicuous promesonotal suture that separates it from the other two species. This is the only character that separates T. orientale from T. malagasy , and it is possible that both are in fact conspecific. Yet the promesonotal suture is completely absent in all the examined T. malagasy material, and we currently consider these ants to belong to two different species.

Tetramorium ryanphelanae and T. malagasy share the same general habitus and almost similar morphometric ranges, but T. ryanphelanae is a much hairier species than T. malagasy . The latter lacks standing hairs on waist segments and first gastral tergite, and shows a short, appressed pubescence on the first gastral tergite, whereas in T. ryanphelanae standing hairs are usually present on the waist segments and first gastral tergite in combination with a comparatively long, appressed pubescence. Another difference, although not very pronounced, is the propodeal spine length, which is slightly longer in T. malagasy (PSLI 33–37) than in T. ryanphelanae (PSLI 28–33). Furthermore, the antennal scapes of the latter species are comparatively longer (SI 76–78) than in T. malagasy (SI 71–74).

In addition, the distribution ranges of both species are exclusive. Tetramorium malagasy can be mainly found in the west, south, and east, and is only known from the three north-western localities mentioned above, whereas T. ryanphelanae seems to be restricted to the northern-most part of Madagascar. The northern-most record of T. malagasy at Ambato is still moderately far from the known distribution range of T. ryanphelanae . Nevertheless, the allopatric distribution of the two species could also be interpreted to mean that these ants are geographic variations of the same species. However, pilosity and pubescence, especially on the first gastral tergite, is generally a very useful character for species discrimination within Tetramorium since it differs very little within a species while there are often great differences between species. Consequently, especially on the basis of very different pilosity patterns and additional small but distinct differences in scape and propodeal spine lengths, we consider both sufficiently discrete from one another to justify their species status.

Etymology

The new species is dedicated to Madagascar, its people and language. The species epithet is a noun in apposition and thus invariant.

Material examined

MADAGASCAR: Antananarivo, 10 km NE Antananarivo, Lac Alarobie, 18° 45' 32.6'' S, 47° 33' 45.1'' E, 1360 m, 10.III.1991 (G.D. Alpert); Antananarivo, Antsahadinta, 19.0128 S, 47.40668 E, 1403 m, urban garden, 6.V.2007 (B.L. Fisher et al.); Antananarivo, Iharanandriana, 19.15823 S, 47.49702 E, 1513 m, Uapaca woodland, 9.V.2007 (B.L. Fisher et al.); Antsiranana, Ampasindava, Forêt d'Ambilanivy, 3.9 km 181° S Ambaliha, 13.79861 S, 48.16167 E, 600 m, rainforest, 4.-9.III.2001 (B.L. Fisher et al.); Antsiranana, Forêt Ambato, 26.6 km 33° Ambanja, 13.4645 S, 48.55167 E, 150 m, rainforest, 8.XII.2003 (B.L. Fisher); Antsiranana, Forêt d'Anabohazo, 21.6 km 247° WSW Maromandia, 14.30889 S, 47.91433 E, 120 m, tropical dry forest, 11.-16.III.2001 (B.L. Fisher et al.); Fianarantsoa, Forêt d'Analalava, 29.6 km 280° W Ranohira, 22.59167 S, 45.12833 E, 700 m, tropical dry forest, 1.- 5.II.2003 (B.L. Fisher et al.); Fianarantsoa, Forêt d'Atsirakambiaty, 7.6 km 285° WNW Itremo, 20.59333 S, 46.56333 E, 1550 m, montane rainforest, 22.-26.I.2003 (B.L. Fisher et al.); Fianarantsoa, P.N. Isalo, 9 km NNW Ranohira, 22 29 S, 45 23 E, 800 m, rainforest, 16.II.1993 (P.S. Ward); Fianarantsoa, 900 m E of Isalo National Park Interpretive Center, 22.62667 S, 45.35817 E, 750 m, open area near stream, 22.-29.XI.2002 (R. Harin'Hala); Fianarantsoa, 1 km E of Isalo National Park Interpretive Center, 22.62667 S, 45.35817 E, 885 m, dry wash, 15.X.- 9.XI.2001 (M.E. Erwin, F.D. Parker & R. Harin'Hala); Fianarantsoa, 1 km E of Isalo National Park Interpretive Center, 22.62667 S, 45.35817 E, 885 m, dry wash, 29.XII.2001 - 5.I.2002 (R. Harin'Hala); Fianarantsoa, 1 km E of Isalo National Park Interpretive Center, 22.62667 S, 45.35817 E, 885 m, dry wash, 15.-29.IV.2002 (R. Harin'Hala); Fianarantsoa, 1 km E of Isalo National Park Interpretive Center, 22.62667 S, 45.35817 E, 885 m, dry wash, 5.- 17.III.2003 (R. Harin'Hala); Fianarantsoa, P.N. Ranomafana, Tolongoina-Ampasimpotsy 1/2, 21.47993 S, 47.55707 E, 577 m, 10.IV.2003 (V.C. Clark); Fianarantsoa, Parc National d'Isalo, 9.1 km 354° N Ranohira, 22.48167 S, 45.46167 E, 725 m, gallery forest, 27.-31.I.2003 (B.L. Fisher et al.); Fianarantsoa, Réserve Forestière d'Agnalazaha, Mahabo, 42.9 km 215° Farafangana, 23.19383 S, 47.723 E, 20 m, littoral rainforest, 19.IV.2006 (B.L. Fisher et al.); Fianarantsoa, Tsaranoro, 32.8 km 229° Ambalavao, 22.08483 S, 46.77633 E, 950 m, rainforest, 14.IV.2006 (B.L. Fisher et al.); Fianarantsoa, Tsaranoro, 32.8 km 230° Ambalavao, 22.08317 S, 46.774 E, 975 m, savannah woodland, 14.IV.2006 (B.L. Fisher et al.); Mahajanga, Forêt de Tsimembo, 11.0 km 346° NNW Soatana, 18.99528 S, 44.4435 E, 50 m, tropical dry forest, 21.-25.XI.2001 (B.L. Fisher et al.); Mahajanga, Parc National de Namoroka, 17.8 km 329° WNW Vilanandro, 16.37667 S, 45.32667 E, 100 m, tropical dry forest, 8.-12.XI.2002 (B.L. Fisher et al.); Mahajanga, Parc National de Namoroka, 16.9 km 317° NW Vilanandro, 16.40667 S, 45.31 E, 100 m, tropical dry forest, 12.-16.XI.2002 (B.L. Fisher et al.); Mahajanga, Parc National Tsingy de Bemaraha, 10.6 km ESE 123° Antsalova, 18.70944 S, 44.71817 E, 150 m, tropical dry forest on Tsingy, 16.-20.XI.2001 (B.L. Fisher et al.); Mahajanga, Réserve forestière Beanka, 50.2 km E Maintirano, 18.02649 S, 44.05051 E, 250 m, tropical dry forest on tsingy, 19-23.X.2009 (B.L. Fisher et al.); Mahajanga, Réserve forestière Beanka, 50.2 km E Maintirano, 17.88756 S, 44.47265 E, 153 m, tropical dry forest on tsingy, 31.X.2009 (B.L. Fisher et al.); Mahajanga, Réserve forestière Beanka, 50.7 km E Maintirano, 17.88021 S, 44.46877 E, 140 m, tropical dry forest on tsingy, 28.X.-1.XI.2009 (B.L. Fisher et al.); Mahajanga, Réserve Spéciale de Bemarivo, 23.8 km 223° SW Besalampy, 16.925 S, 44.36833 E, 30 m, tropical dry forest, 19.-23.XI.2002 (B.L. Fisher et al.); Toamasina, Ambatovy, 12.4 km NE Moramanga, 18.84773 S, 48.29568 E, 1000 m, montane rainforest, 5.–8.III.2007 (B.L. Fisher et al.); Toamasina, Ambatovy, 12.4 km NE Moramanga, 18.85813 S, 48.28488 E, 1040 m, montane rainforest, 5.–8.III.2007 (B.L. Fisher et al.); Toamasina, Ambatovy, 12.4 km NE Moramanga, 18.85813 S, 48.28488 E, 1040 m, grassland, 5.–8.III.2007 (B.L. Fisher et al.); Toamasina, Forêt Ambatovy, 14.3 km 57° Moramanga, 18.85083 S, 48.32 E, 1075 m, montane shrubland, on rock, 18.XII.2004 (B.L. Fisher); Toliara, BezaMahafaly, 27 km E Betioky, 23.65 S, 44.63333 E, 135 m, tropical dry forest, 23.IV.1997 (B.L. Fisher); Toliara, Forêt de Beroboka, 5.9 km 131° SE Ankidranoka, 22.23306 S, 43.36633 E, 80 m, tropical dry forest, 12.– 16.III.2002 (B.L. Fisher et al.); Toliara, Forêt de Mahavelo, Isantoria River, 5.5 km 37° NE Ifotaka, 24.75361 S, 46.1515 E, 115 m, spiny forest/thicket, 31.I.2002 (B.L. Fisher et al.); Toliara, Forêt de Mite, 20.7 km 29° WNW Tongobory, 23.52417 S, 44.12133 E, 75 m, gallery forest, 27.II.–3.III.2002 (B.L. Fisher et al.); Toliara, Forêt Vohidava 88.9 km N Amboasary, 24.24067 S, 46.28783 E, 500 m, spiny forest/dry forest transition, 7.–9.XII.2006 (B.L. Fisher et al.); Toliara, Mahafaly Plateau, 6.2 km 74° ENE Itampolo, 24.65361 S, 43.99667 E, 80 m, spiny forest/thicket, 21.–25.II.2002 (B.L. Fisher et al.); Toliara, Manatantely, 8.9km NW Tolagnaro, 24.9815 S, 46.92567 E, 100 m, rainforest, 27.–28.XI.2006 (B.L. Fisher et al.); Toliara, Parc National d'Andohahela, Forêt d'Ambohibory, 1.7 km 61° ENE Tsimelahy, 36.1 km 308° NW Tolagnaro, 24.93 S, 46.6455 E, 300 m, tropical dry forest, 16.–20.I.2002 (B.L. Fisher et al.); Toliara, Parc National de Kirindy Mite, 16.3 km 127° SE Belo sur Mer, 20.79528 S, 44.147 E, 80 m, tropical dry forest, 6.–10.XII.2001 (B.L. Fisher et al.); Toliara, Parc National de Zombitse, 19.8 km 84° E Sakaraha, 22.84333 S, 44.71 E, 770 m, tropical dry forest, 5.–9.II.2003 (B.L. Fisher et al.); Toliara, Parc National de Zombitse, 17.7 km 98° E Sakaraha, 22.88833 S, 44.70167 E, 760 m, tropical dry forest, 8.II.2003 (B.L. Fisher et al.); Toliara, Ranobe, 23.03918 S, 43.61153 E, 30 m, spiny forest/thicket, 25.– 28.IV.2003 (Frontier Project); Toliara, Res. Beza Mahafaly, Parcel 1, 23° 39' S, 44° 38' E, 130 m, tropical dry forest, 13.II.1993 (P.S. Ward); Toliara, Res. Beza Mahafaly, Parcel 1, 23° 39' 30'' S, 44° 37' 44'' E, 160 m, tropical dry forest, 13.II.1993 (E. Rajeriarison, G.D. Alpert et al.); Toliara, Réserve Privé Berenty, Forêt de Malaza, Mandraré River, 8.6 km 314° NW Amboasary, 25.00778 S, 46.306 E, 40 m, gallery forest, 6.II.2002 (B.L. Fisher et al.); Toliara, 15 km E Sakaraha, 22° 54 S, 44° 41' E, 760 m, tropical dry forest, 15.II.1993 (P.S. Ward); Toliara, southern Isoky-Vohimena Forest, 59 km NE Sakaraha, 22.46667 S, 44.85 E, 730 m, tropical dry forest, 21.I.1996 (B.L. Fisher); Toliara, Vohibasia Forest, 59 km NE Sakaraha, 22.46667 S, 44.85 E, 780 m, tropical dry forest, 13.I.1996 (B.L. Fisher).