Tetramorium kulickae, Radchenko & Dlussky, 2015

Radchenko, A. G. & Dlussky, G. M., 2015, First Record Of Fossil Species Of The Genus Tetramorium (Hymenoptera, Formicidae), Vestnik Zoologii 49 (4), pp. 311-316 : 313-315

Tetramorium kulickae sp. n.

Leptothorax sp. C : Kosmowska-Ceranowicz, 2001: 59. Tetramorium sp. B : Dlussky, Rasnitsyn, 2009: 1032.

M a t e r i a l e x a m i n e d: worker, holotype, No. 20246 , Muzeum Ziemi PAN, Baltic Amber, Gdansk-Stogi, Poland .

E t y m o l o g y. The species is dedicated the memory of Polish palaeoentomologist, Dr. Róża Kulicka (1944–1999).

W o r k e r ( fig. 3–5 ). Head longer than broad, with subparallel sides, very feebly concave occipital margin and rounded occipital corners. Lateral portions of clypeus raised in both sides into a sharp shield-like ridge in front of antennal insertions, so that antennal sockets separated from clypeal surface. Eye well developed, of moderate size. Anterior clypeal margin convex. Antenna 12-segmented, with 3-segmented apical club, scape short, far not reaching occipital margin.

Mesosoma low (ML/MH 2.89), with distinct but shallow metanotal groove, promesonotum somewhat flattened. Propodeum with blunt denticles. Petiole with quite long peduncle, strongly concave anterior surface, its node not high, with widely rounded dorsum (PL/PW 1.17, PL/ PH 1.40) Postpetiole subglobular (PPL/PPW 1.00).

Spurs on the mid and hind tibia are obscure.

Whole mesosoma with quite coarse longitudinal, slightly sinuous rugosity. Sculpture on head barely visible, but head seems to be longitudinally rugose; petiolar and postpetiolar nodes seem to be coarsely punctated. Mesosomal dorsum with long, thin erect hairs.

Total length ca 2.5–2.7 mm.

Measurements (in mm): ML 0.81, MH 0.28, PL 0.21, PH 0.15, PW 0.18, PPL 0.15, PPW 0.15.

Queen and male unknown.

Taxonomic notes

Kosmowska-Ceranowicz (2001) recorded two species from the Baltic Amber collected near Gdansk (Stogi) in the Catalogue of amber collection of Tadeusz Giecewicz, deposited in the Museum of the Earth. Their collecting numbers fully correspond with those of T. paparamatum and T. kulickae , and determined by her as Tetramorium sp. n. and Leptothorax sp. , respectively.

Dlussky, Rasnitsyn (2009) recorded three undescribed species of this genus from the Baltic and Rovno ambers. Two of them from Baltic amber we described above, but record from the Rovno amber was based on misidentification, and we identify now this specimen as Fallomyrma transversa Dlussky et Radchenko, 2006 .

Radchenko (1992 a, b) established six species groups for Tetramorium of the former USSR. One of them, inerme group, is characterized by the relatively small queens with flattened scutum and scutellum, scutum is narrowed anteriorly so that anterio-lateral angles of pronotum are visible from above. Additionally, body sculpture in queens and workers reduced, head dorsum and mesosoma mostly smooth or at most with the fine striation. We placed T. paraarmatum sp. n. to this group.

The species of caespitum group have much bigger queens, their scutum distinctly convex, not narrowed anteriorly, so that anterio-lateral angles of pronotum covered by scutum and invisible or very barely visible from above. Body sculpture of queens and workers well developed, head dorsum and mesosoma longitudinally rugulose, while this sculpture in not very coarse. Since we described T. kulickae sp. n. based on workers, we tentatively place it to this group.

Based on the main diagnostic features, e. g., the body size, the shape of mesosoma, the reduced body sculpture, presence of distinct propodeal teeth, T. paraarmatum sp. n. resembles modern species T. armatum . At the same time, T. kulickae sp. n. is similar to modern species of Tetramorium caespitum group, e. g., T. caespitum s. l., T. impurum (Foerster, 1850) or T. hungaricum Röszler, 1935 . Nevertheless, we do not think that modern ant species might exist in the Late Eocene, what is supported by the all existing data. For example, several fossil Late Eocene amber ant species are very similar to modern ones, e. g. extinct Formica flori Mayr, 1868 to extant F. fusca Linnaeus, 1758 , Lasius schiefferdeckeri Mayr, 1868 to L. niger Linnaeus, 1758 , etc., but no one doubts their heterospecifity.

Figures

Fig. 3–5. Details of structure of Tetramorium kulickae sp. n., holotype, worker: 3 — mesosoma and head in profile; 4 — waist and gaster, dorsal view; 5 — antenna funiculus. Scale bar 1 mm.