Temnothorax conatensis Galkowski & Lebas, 2016

González, Javier Arcos, 2021, Description of Temnothorax estel sp. nov. (Hymenoptera: Formicidae), with a review of the Iberian species of the sordidulus species-complex, Zootaxa 5005 (2), pp. 145-160 : 149-150

Temnothorax conatensis Galkowski & Lebas, 2016

( Fig. 2A and 6A )

Material. 6 workers, Spain, Mont-Rebei (Lleida), IIX.2008, 42°03’51.0”N 0°41’16.0”E, 1300 m, Fede García leg. One individual with a right hypoplasic propodeal spine .

Diagnosis. Dark brown to black coloration with infuscate antennal funiculus and femora, head and mesosoma with reticulated ground sculpture, inconspicuous to moderately-impressed metanotal groove (mean MGr/CS 0.797%), moderately long propodeal spines and long petiole (mean PEL/CS 0.417). Larger than other Iberian taxa in the sordidulus species-complex (mean CS 0.636 mm).

Comments. The investigated material, the original description and the imaged holotype of T. conatensis in Antweb (ANTWEB1032082) match the concept of the sordidulus species-complex in coloration, head and mesosoma sculpture, metanotal groove depth, length of propodeal spines, concave anterior face of petiole and body proportions. In the Palearctic context, workers show intermediate characteristics between T. sordidulus and T. tergestinus , but T. conatensis is easily differentiated by its larger size (CS> 0.600), shorter mesosoma (mean ML/CS 1.227), inconspicuous to poorly developed metanotal groove and lower petiole (mean PEH/CS 0.342). The petiole is usually longer, with rounded apex and slightly convex dorsal surface, while in T. sordidulus and T. tergestinus it is shorter and usually truncated.

Temnothorax conatensis is most similar to T. platycephalus from Iberia and T. melas from Corsica, together forming a sub-complex of very robust and slender species hardly differentiated from each other. Workers of all three species are of dark brown coloration, elongated head, small FRS/CS, inconspicuous to poorly-developed metanotal groove and well developed subpetiolar process. The petiole shape of T. conatensis and T. platycephalus varies from triangular to truncated with distinct concave posterior face, as seen also in some specimens of T. melas (see below). Undoubtably, T. conatensis and T. platycephalus constitute a pair of cryptic species, with>70% of the characters measured showing overlapping ranges and nearly identical appearance. However, a striking difference is found in the HL/HWb parameter, with T. platycephalus having a much longer head (HL/HWb 1.295 –1.345) than T. conatensis (HL/HWb 1.222 –1.226); the postpetiole is also narrower in the first (mean PPW/CS 310 vs. 330). Both species share the same habitat and nesting preferences and may co-occur in North Iberia.

The case of T. melas is intriguing. The imaged specimens in Antweb (CASENT0915390, CASENT0911189) are visually indistinguishable from the workers of T. platycephalus here evaluated, both sharing the characteristically elongated head feature, which separates them from T. conatensis . Seifert (1995) stated that the “frontal and dorsal profile lines of the petiole meet in a sharp angle” in T. melas , but the petiolar profile appears to be highly variable in this complex of species, and short and peaked petioles are also found in T. platycephalus and T. conatensis . On the other extreme of the spectrum, distinctly truncated petioles are seen in T. conatensis and T. platycephalus , and an imaged specimen of T. melas suggests it is also the case of this species (CASENT0906689). A preliminary comparison of my data of T. platycephalus and the indexes presented by Seifert (2006) for T. melas , measuring head width as HW instead of HWb, demonstrates their overall morphometric similarity and points to a cryptic identity of both species ( Table 1). However, the isolation of T. melas in Corsica makes their separation easy based on a geographic criterion.

García et al. (2018) examined the same material from Mont-Rebei and offered a comparison with T. grouvellei ( Bondroit, 1918) , but this is a very different species belonging to the exilis group that has coarse striation without reticulated ground sculpture and distinctly long and domed petiole. Finally, the black photo-stacked specimen from France that appears in Blatrix (2013) is morphometrically concordant with T. sordidulus and not with T. conatensis nor T. platycephalus , but it shows an atypical short petiole that would be worth investigating.

Nests of T. conatensis were found in rock crevices and on the ground, in an altitude between 600–1500 meters ( Galkowski & Lebas 2016; García et al. 2018).

Figures

FIGURE 2. Head (left) and lateral view (right) of the workers of (A) T. conatensis (Mont-Rebei, Lleida), (B) T. estel sp. nov. (Sierra de Cazorla, Jaén), (C) T. ibericus (Sierra de Javalambre, Teruel), and (D) T. platycephalus (Sierra de Cazorla, Jaén).

FIGURE 6. Typical coloration and morphological appearance of the species in the Iberian sordidulus species-complex. Sculpture of frons (left column) and lateral view of workers (right column); T. conatensis (A), T. estel sp. nov. (B), T. ibericus (C) and T. platycephalus (D).