Tetramorium valky 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 : 108-111

Tetramorium valky Hita Garcia & Fisher sp. n.

(figs 128, 133, 135, 153, 154, 155)

Holotype worker, MADAGASCAR, Toamasina, Montagne d'Akirindro 7.6 km 341° NNW Ambinanitelo, 15.2883 S, 49.5483 E, 600 m, rainforest, ex rotten stick on ground, collection code BLF08376, 17.–21.III.2003 (B.L Fisher, C. Griswold et al.) ( CASC: CASENT0496394 ) . Paratypes, seven workers with same data as holotype ( CASC: CASENT0496395 ; CASENT0496396; CASENT0496397) ; seven workers with same data as holotype except sampled from sifted litter (leaf mold, rotten wood) and collection code BLF08250 ( CASC: CASENT0039323 ; CASENT0039384; MCZ: CASENT0039325 ; MHNG: CASENT0039552 ; NHMB: CASENT0039320 ) ; one worker with same data as holotype except sampled from yellow pan trap and collection code BLF08255 ( BMNH: CASENT049289 ) ; one worker with same data as holotype except sampled from beating low vegetation and collection code BLF08359 ( CASC: CASENT0496108 ) ; nine workers with same data as holotype except sampled from rotten log and collection code BLF08382 ( CASC: CASENT0496369 ; CASENT0496370; CASENT0496371) .

Diagnosis

Tetramorium valky can be well differentiated from the other species group members by the following combination of characters: head longer than wide to as long as wide (CI 92–100); mesosoma strongly marginate from sides to dorsum; petiolar node in profile triangular cuneiform to squamiform, usually strongly anteroposteriorly compressed dorsally, sometimes whole node strongly anteroposteriorly compressed; mesosomal dorsum completely unsculptured, smooth, and shining; abundant hairs on mesosomal dorsum not restricted to lateral margins; body of dark brown to black colour.

Description

HL 0.62–0.81 (0.73); HW 0.58–0.80 (0.71); SL 0.48–0.63 (0.57); EL 0.14–0.19 (0.17); PH 0.31–0.39 (0.36); PW 0.44–0.61 (0.54); WL 0.77–0.99 (0.90); PSL 0.24–0.41 (0.34); PTL 0.06–0.11 (0.08); PTH 0.28–0.39 (0.34); PTW 0.21–0.32 (0.27); PPL 0.16–0.27 (0.23); PPH 0.25–0.39 (0.32); PPW 0.22–0.36 (0.31); CI 92–100 (96); SI 78–84 (81); OI 23–26 (24); DMI 57–63 (60); LMI 39–43 (40); PSLI 39–52 (46); PeNI 46–54 (50); LPeI 16–31 (24); DPeI 237–500 (336); PpNI 48–64 (57); LPpI 62–81 (72); DPpI 120–148 (133); PPI 102–124 (114) (15 measured).

Head longer than wide to as long as wide (CI 92–100). Anterior clypeus medially impressed. Frontal carinae well developed, ending between posterior eye margin and posterior head margin. Antennal scrobes faint to absent. Antennal scapes short to moderate, not reaching posterior head margin (SI 78–84). Eyes moderate to large (OI 23– 26). Mesosomal outline in profile moderately convex, strongly marginate from lateral to dorsal mesosoma; promesonotal suture absent; metanotal groove present but weak; mesosoma comparatively high, compact, and stout (LMI 39–43). Propodeal spines very long, spinose, and acute (PSLI 39–52); propodeal lobes small and broadly triangular. Petiolar node in profile triangular cuneiform to squamiform, usually strongly anteroposteriorly compressed dorsally, approximately 3.2 to 6.3 times higher than long (LPeI 16–31), anterior and posterior faces usually not parallel, anterodorsal margin generally situated higher than posterodorsal, dorsum distinctly tapering backwards posteriorly, sometimes whole node strongly anteroposteriorly compressed, anterior and posterior faces almost parallel and node noticeably squamiform; node in dorsal view extremely transverse, between 2.3 to 5 times wider than long (DPeI 237–500). Postpetiole in profile approximately rounded and weakly anteroposteriorly compressed, approximately 1.2 to 1.6 times higher than long (LPpI 62–81), in dorsal view approximately 1.2 to 1.5 times wider than long (DPpI 120–148). Postpetiole in profile usually appearing as voluminous as petiolar node, in dorsal view weakly wider than petiolar node (PPI 102–124). Mandibles with distinct longitudinal sculpture, sometimes weak, but generally present; clypeus mostly unsculptured, smooth, and shining, few short rugulae or traces of rugulae present; cephalic dorsum between frontal carinae with six to nine longitudinal rugae or rugulae, median ruga usually shorter than frontal carinae and diverging approximately at eye level into two rugae running to posterior clypeal margin, remaining rugulae generally of same length as frontal carinae, often broken and shorter; lateral and ventral head with longitudinal sculpture, especially anteriorly, posteriorly only weakly sculptured or unsculptured. Ground sculpture on head usually faint to absent, sometimes moderately reticulate-punctate. Mesosoma laterally mostly unsculptured, weak sculpture present posteriorly; dorsal mesosoma completely unsculptured, smooth, and shiny. Waist segments and gaster completely unsculptured, smooth, and shiny. All dorsal surfaces of body with abundant, long, erect pilosity, hairs on mesosomal dorsum not restricted to lateral margins. Body of uniform dark brown to black colour.

Notes

The new species is distributed throughout eastern Madagascar from Mandena and St. Luce in the south to Ambanizana and the type locality Montagne d'Akirindro in the north. In addition, it is restricted to lowland rainforest habitats at elevations of 10 to 600 m where it appears to live in leaf litter and lower vegetation.

Tetramorium valky cannot be confused with T. norvigi or T. shamshir since the latter two have a sculptured mesosomal dorsum and are yellowish in colour, whereas T. valky has a completely unsculptured and smooth mesosomal dorsum and is very dark brown to black in colour. Furthermore, it is not likely to be confused with T. silvicola due to the much longer head of the latter (CI 88–90), while the head of T. valky is much broader (CI 92– 100). Also, T. valky differs significantly from T. hector , and the shape of the petiolar node separates both very well. The node of T. hector in profile is cuneiform and comparatively thick (DPeI 134–147) versus triangular to squamiform and much thinner in T. valky (DPeI 237–500). The remaining species, T. marginatum , is morphologically close to T. valky , but both can be easily distinguished by the pilosity pattern on the mesosomal dorsum. Tetramorium marginatum has long standing hairs only at the dorsolateral margins of the mesosoma and rarely at the dorsal border between mesonotum and propodeum, whereas the hairs of T. valky are present all over the mesosomal dorsum. Also, the petiolar node of T. valky is often more strongly compressed dorsally (LPeI 16–31; DPeI 236–500) than in T. marginatum (LPeI 29–47; DPeI 189–300), although this character has to be treated with caution since the morphometric ranges of the two species overlap. The shape of the mesosoma in lateral view is also much more convex in T. marginatum than in T. valky . Finally, the propodeum is often very high, much higher than the pronotum, in T. marginatum while it is distinctly lower in the latter, although this character is often difficult to compare.

One aspect of intraspecific variation merits particular mention. The petiolar node is usually markedly triangular cuneiform in lateral view with a strongly anteroposteriorly compressed dorsum. This is the case for almost all of the examined material. Nonetheless, in the few available specimens from Ranomafana, most of the node is anteroposteriorly compressed, causing it to look squamiform and very thin. This difference, however, is not sufficient to justify the heterospecificity of these specimens. Instead we consider this to be intraspecific variation.

Etymology

The name of the new species is an arbitrary combination of letters. The species epithet is a noun in apposition, and thus invariant.

Material examined

MADAGASCAR: Fianarantsoa, Forêt Classée Vatovavy, 7.6 km 122º Kianjavato, 21.4 S, 47.94 E, 175 m, rainforest, 6.–8.VI.2005 (B.L. Fisher et al.); Fianarantsoa, 9 km ESE Ranomafana, nr. Ifanadiana, 21° 17' S, 47° 32' E, 600 m, 28.IV.1989 (P.S. Ward); 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.); Toamasina, Andranobe, 5.3 km SSE Ambanizana, 15.66667 S, 49.96667 E, 425 m, rainforest, 19.XI.1993 (B.L. Fisher); Toamasina, Ile Sainte Marie, Forêt Kalalao, 9.9 km 34° Ambodifotatra, 16.9225 S, 49.88733 E, 100 m, rainforest, 24.–27.XI.2005 (B.L. Fisher et al.); Toamasina, Montagne d'Akirindro 7.6 km 341° NNW Ambinanitelo, 15.28833 S, 49.54833 E, 600 m, rainforest, 17.–21.III.2003 (B.L. Fisher, C. Griswold et al.); Toamasina, Parc National Mananara-Nord, 7.1 km 261° Antanambe, 16.455 S, 49.7875 E, 225 m, rainforest, 14.–16.XI.2005 (B.L. Fisher et al.); Toamasina, Res. Ambodiriana, 4.8 km 306° Manompana, along Manompana river, 16.67233 S, 49.70117 E, 125 m, rainforest, 18.–19.XI.2005 (B.L. Fisher et al.); Toamasina, Réserve Naturelle Betampona, 34.08 km 332° Toamasina, 17.91977 S, 49.20039 E, 525 m, rainforest, 11.–18.I.2009 (B.L. Fisher); Toamasina, Réserve Betampona, Camp Rendrirendry 34.1 km 332° Toamasina, 17.924 S, 49.19967 E, 390 m, rainforest, 28.V.2005 (B.L. Fisher et al.); Toamasina, Réserve Naturelle Betampona, 34.1 km 332° Toamasina, 17.916135 S, 49.20185 E, 550 m, rainforest, 10.–17.II.2008 (B.L. Fisher); Toamasina, Réserve Naturelle Betampona, 34.1 km 332° Toamasina, 17.916135 S, 49.20185 E, 550 m, rainforest, 27.IV.–4.V.2008 (B.L. Fisher); Toamasina, Réserve Naturelle Betampona, 34.1 km 332° Toamasina, 17.916135 S, 49.20185 E, 550 m, rainforest, 16.–23.XI.2008 (B.L. Fisher); Toamasina, Réserve Naturelle Betampona, 34.1 km 332° Toamasina, 17.916135 S, 49.20185 E, 550 m, rainforest, 1.–8.III.2009 (B.L. Fisher); Toamasina, Réserve Nationale Intégrale Betampona, Betampona 35.1 km NW Toamasina, 17.91801 S, 49.20074 E, 500 m, rainforest, 16.–17.XII.2007 (B.L. Fisher); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.77274 S, 49.26551 E, 450 m, rainforest, 20.–22.II.2010 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.76912 S, 49.26704 E, 475 m, rainforest, 21.II.2010 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.77468 S, 49.26551 E, 355 m, rainforest along river, 21.II.2010 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.7633 S, 49.26692 E, 520, rainforest, 22.–24.II.2010 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, – 16.7702 S, 49.26638 E, 470 m, rainforest, 23.II.2010 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.7674 E, 49.26813 E, 500 m, rainforest, 23.II.2010 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.77274 E, 49.26551 E, 450 m, rainforest, 23.II.2010 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.8162 E, 49.29202 E, 425 m, rainforest, 25.II.2010 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.81753 E, 49.29498 E, 360 m, rainforest, 25.– 27.II.2010 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.81745 E, 49.2925 E, 400 m, rainforest, 26.II.2010 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.81209 E, 49.29216 E, 460 m, rainforest, 26.II.2010 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.80561 E, 49.29507 E, 480 m, rainforest, 27.II.2010 (B.L. Fisher et al.); Toamasina, Sahafina forest 11.4 km W Brickaville, 18.81445 S, 48.96205 E, 140 m, rainforest, 13.–14.XII.2007 (B.L. Fisher et al.); Toamasina, S.F. Tampolo, 10 km NNE Fenoarivo Atn., 17.2825 S, 49.43 E, 10 m, littoral rainforest, 4.–12.IV.1997 (B.L. Fisher); Toamasina, Tampolo, Parcelle K9, 17.175 S, 49.268 E, 10 m, littoral forest, 19.IV.2004 (B.L. Fisher et al.); Toliara, 2.7 km WNW 302° Ste. Luce, 24.77167 S, 47.17167 E, 20 m, littoral rainforest, 9.–11.XII.1998 (B.L. Fisher); Toliara, Foret Ivohibe, 55 km N Tolagnaro, 24.569 S, 47.204 E, 200 m, rainforest, 2.–4.XII.2006 (B.L. Fisher et al.); Toliara, Mandena, 8.4 km NNE 30° Tolagnaro, 24.95167 S, 47.00167 E, 20 m, littoral rainforest, 20.XI.1998 (B.L. Fisher); 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).