Temnothorax saxatilis

Schulz, Andreas, Heinze, Jürgen & Pusch, Katja, 2007, Description of two new Te m n o t h o r a x species (Hymenoptera: Formicidae) from Italy, Zootaxa 1471, pp. 1-14 : 12-13

Temnothorax saxatilis nov. spec.

( Figs 12, 13 , 23 , 27 , 32, 33 )

Holotype worker. ITALY, Abruzzi, Prov. L’Aquila, Gran Sasso, 6 km NE. Castel del Monte, 1600m.a.s.l. 12.iv.1994, Leg. M. Sanetra [ SMNK].

Paratypes. 8 workers and 1 gyne, same data as holotype [ SMNG, MHNG, MCSN, PCAS].

Etymology. The Latin word means “between the rocks,” a tribute to the name of the type locality, Gran Sasso.

Description of worker. Measurements and indices [holotype] (n=10): HL [0.637] 0.62±0.02 (0.59–0.66), HW [0.532] 0.51±0.02 (0.48–0.54), SL [0.428] 0.42±0.02 (0.38–0.43), FCD [0.214] 0.21±0.01 (0.20–0.22), ML [0.822] 0.77±0.03 (0.72–0.82), MW [0.399] 0.37±0.02 (0.35–0.40), PSL [0.081] 0.08±0.01 (0.07–0.10), PEL [0.261] 0.25±0.02 (0.23–0.28), PEW [0.176] 0.16±0.01 (0.14–0.18), PEH [0.228] 0.21±0.01 (0.19– 0.23), PPW [0.228] 0.21±0.01 (0.20–0.23), HS 0.56±0.02 (0.53–0.59), HW/HL 0.82±0.02 (0.78–0.84), SL/ HS 0.74±0.02 (0.67–0.77), FCD/HS 0.37±0.01 (0.35–0.39), MW/ML 0.46±0.01 (0.48–0.50), PSL/ML 0.11±0.01 (0.09–0.12), PEH/PEL 0.84±0.05 (0.76–0.90), PEW/PEL 0.64±0.04 (0.59–0.68), PEW/PPW 0.75±0.03 (0.71–0.79).

Head slender, narrower anterior to eyes than posteriorly, vertexal corners evenly rounded, posterior vertexal margin medially slightly concave. Anterior margin of clypeus slightly convex, medially with a shallow depression or straight. Frontal carinae short, nearly parallel-sided. Scapes short. Mesosoma relatively narrow, in lateral view moderately high, with the dorsal margin mainly straight, or slightly convex. Propodeal spines short, broadly attached, nearly triangular, in dorsal view nearly linear and only slightly divergent distally, with rounded tips. Petiole pedunculate, average high and broad, in lateral view with a broadly rounded node. Anterodorsal petiolar node weakly angulate, anterior petiolar face concave. In dorsal view the node is evenly rounded, without angles or a crest. In dorsal view the postpetiole is subrectangular, slightly broader anteriorly than posteriorly.

Mandibles partially rugoreticulate, lucid. Frontal triangle faintly granulate, lateral parts of clypeus irregularly striate to rugoreticulate, medially faintly granulate, with one superimposed shallow carina, surface subopaque. Frons reticulate with some striae, sublucid. Genae rugoreticulate, around the eyes, and whole vertex mainly reticulate. Larger specimens more rugoreticulate. Ventral surface of head faintly reticulate, medially lucid. Entire mesosoma densely reticulate, with a few superimposed rugulae on dorsum and pronotum. Propodeum between the propodeal spines and postpetiole reticulate, petiolar dorsum rugoreticulate, dorsal face of propodeum reticulate. Gaster lucid. Colour dark ferrugineus to brown; head darker than gaster and appendages. Antennal clubs dark brown. Standing pilosity of head, mesosoma and gaster sparse, transparent, with blunt tips.

Description of gyne. Measurements and indices (n=1): HL 0.74, HW 0.67, SL 0.50, FCD 0.26, ED 0.20, ML 1.33, MW 0.76, PSL 0.05, PEL 0.31, PEW 0.23, PEH 0.28, PPL 0.20, PPW 0.30, HS 0.72, HW/HL 0.94, SL/HS 0.70, FCD/HS 0.36, ED/HS 0.28, MW/ML 0.57, PSL/ML 0.04, PEH/PEL 0.89, PEW/PEL 0.73, PPL/ PPW 0.68, PEW/PPW 0.76.

Head in relation to the mesosoma large and broad, especially behind the eyes. Genae weakly convex and convergent. Behind the eyes the margins are convex, vertexal margin broadly rounded, medially nearly linear. Anterior margin of clypeus slightly convex, medially with a shallow depression. Frontal triangle negligibly impressed. Eyes very small. Frontal carinae short and widely separated. Scapes short. Mesosoma in lateral view flat. Scutellum distinctly broader than long, posterior margin straight. Propodeal spines very short, dentiform.

Petiole pedunculate, average high, but broad, node with a truncated and rounded apex. Anterior-dorsal margin is slightly concave in profile. Subpetiolar process inconspicuous, nearly triangular. In dorsal view with narrow peduncle, strongly divergent, from midlength the sides are nearly parallel. The node apex has rounded, weak lateral corners, in dorsocaudal view. Postpetiole of same shape as in workers.

Mandibles longitudinally striate, lucid. Frontal triangle lucid, clypeus carinate. A small strip of frons nearly unsculptured, lucid, bordered by longitudinal carinae, which are connected by shallow transverse strigae. Each frontal carina fades to less stronger carinae posteriorly. Posterior part of frons reticulo-striate. Genae, surface around the eyes and vertex more strongly rugose, with reticulate interstices. Ventral surface of head reticulo-striate. Lateral parts of mesosoma rugose to carinate with scattered reticulate interstices. Pronotum rugose, mesonotum irregularly and densely carinate with some anastomoses, anterior surface unsculptured medially. Scutellum lucid medially, lateral surface striate. Dorsum of propodeum and surface between the spines transversely carinate. Petiole rugoreticulate, with transverse strigae on dorsum, dorsal petiolar surface and entire postpetiole irregularly reticulate. Dark brown, unicoloured, with the gaster somewhat lighter testaceus to brown. Appendages orange-brown, darker scapes, antennal clubs, and femora.

Differential diagnosis. The workers of T. saxatilis are distinguishable from most Italian Temnothorax by the brown colour in combination with a conspicuously truncated and robust petiole. In comparison to T. saxatilis , T. nigriceps (Mayr, 1855) ( Fig. 14, 15 , 24 ) has longer scapes and is usually bicoloured with ferruginous mesosoma and waist and contrastingly darker head and gaster. Additionally, the sculpture is much rougher and more visible especially on the head and mesosoma. Workers of T. tuberum (Fabricius, 1775) ( Fig. 16, 17 , 25 ) always have a distinctly lighter mesosoma and head, and also stronger sculpture on dorsal head surface, than in T. saxatilis . Other Mediterranean dark coloured Temnothorax species are T. laestrygon (Santschi, 1931) , T. niger (Forel, 1894) and the usually lighter, but sometimes equally dark coloured T. exilis (Emery, 1869) . The petiole of all three species is lower, triangular, and with a more or less distinct apical crest in lateral view. Furthermore, these species occur only at lower elevations with Mediterranean climate. The arboreal species T. affinis (Mayr, 1855) ( Fig. 20 & 21 ) is similar, when specimens are darker than usual, but they differ by distinctly longer propodeal spines. Very rarely specimens of T. affinis may have shorter spines in combination with darker reddish brown colour. In such cases, these specimens have a more triangular petiolar node and a more evenly reticulate head, without superimposed rugae. A morphologically similar species outside Italy is the tentatively determined T. anodontoides (Dlussky & Zabelin, 1985) ( Fig. 18 & 19 ) from Transcaucasia and a probably isolated population on high mountains of southern Greece. Temnothorax anodontoides from Greece can be distinguished from T. saxatilis by longer scapes, shorter propodeal spines, lower waist (Table 3) dark brown to nearly black colour, coarser rugose sculpture, and truncated, weakly rounded dorsum/apex of petiolar node.

For comparison only one gyne of T. saxatilis is available. The gyne of T. nigriceps has longer propodeal spines, more triangular petiolar node in lateral view, and more coarsely sculptured head and mesosoma. Temnothorax tuberum is a morphologically variable species, but has a smaller head and somewhat shorter propodeal spines. Furthermore, in T. tuberum , the mesosoma and especially the scutellum is more densely rugose, and the legs are evenly yellowish, whereas the legs of T. saxatilis are somewhat bicoloured, mostly brown with ferrugineous patches. The gyne of T. affinis ( Fig. 36 & 37 ) is normally lighter coloured than in T. saxatilis , but darker specimens occur. The propodeal spines are usually longer and the petiole is lower in profile. Head sculpture of T. affinis ( Fig. 37 ) is more reticulate and less rugulose, than in T. saxatilis . The brownish to black gynes of T. exilis , T. laestrygon and T. niger are distinctive in their low petiole with a triangular and acute petiolar node in profile. The morphometric differentiation of gynes of T. saxatilis and T. anodontoides from Greece is difficult; only one gyne each is available for comparison. Temnothorax anodontoides has a distinctly lower and truncated petiolar node in profile. In addition, in this species the sculpture is mainly rugose and coarser.

Figures

FIGURES 12 – 21. Temnothorax workers, left: lateral view of body, right: full-face view of head. 12 & 13, T. saxatilis Holotype; 14 & 15, T. nigriceps, Arcadia, Peloponnesos, Greece; 16 & 17, T. tuberum, Südtirol, Italy; 18 & 19, T. anodontoides, Arkadia, Peloponnesos, Greece. 20 & 21, T. affinis, near Spitz, Wachau, Austria.

FIGURES 22 – 25. Temnothorax workers, dorsal views showing first gaster tergite, postpetiole, petiole and mesosoma. 22 T. alienus, Holotype; 23, T. saxatilis, Holotype; 24, T. nigriceps, Arcadia, Peloponnesos, Greece; 25, T. tuberum, Val di Fossa, Alto Edige, Italy.

FIGURES 26 – 27. Temnothorax gynes, lateral view of body. 26, T. alienus Holotype; 27, T. saxatilis Holotype.

FIGURES 28 – 37. Temnothorax gynes, left: dorsal view of body. right: full-face view of head. 28 & 29, T. alienus Holotype; 30 & 31, T. nylanderi, Beira Alta, Sierra de Montemuro, Portugal; 32 & 33, T. saxatilis Holotyp; 34 & 35, T. nigriceps, Arcadia, Peloponnesos, Greece; 36 & 37, T. affinis, near Spitz, Wachau, Austria.