Myrmica eocenica

†Myrmica eocenica Temporal range: Bartonian, Middle to Late Eocene K Pa Eo Ol Mi Pl Baltic amber, Baltic Sea region
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Myrmicini
Genus:	Myrmica
Species:	†M. eocenica
Binomial name
†Myrmica eocenica Radchenko, Dlussky & Elmes, 2007

Photo Gallery

• 

  Radchenko (2023), Figure 3. Myrmica eocenica, worker, holotype: (A) body, dorso-lateral view; (B) propodeal spines, dorsal view; Myrmica electrina, workers: (C) holotype, body, lateral view; paratype (D) body, dorso-lateral view; (E) hind tibia. Scale bars: A, C, G – 1 mm, B, E – 0.5 mm.

Identification

Meso- and metatibiae with pectinate spur; head, mesosoma and waist coarsely sculptured; upper lateroventral corners of head somewhat pointed; eyes located approximately at midlength of sides of head; scape very feebly curved at base (similar to modern Myrmica rubra); mesosoma long and low; petiole long and low; propodeal spines directed mainly backward (seen in profile) and strongly divergent (seen from above).

For differences from Myrmica longispinosa, Myrmica rudis and Myrmica intermedia see those species.

Myrmica eocenica differs from Myrmica electrina, Myrmica dictyosa and Myrmica damzeni by the presence of spurs on the meso- and metatibiae. In additions, in M. dictyosa the entire mesosoma is very coarsely reticulate, while in M. eocenica the propodeal dorsum has sinuous longitudinal rugae; form M. damzeni it differs by a more abundant erect or suberect pilosity on the body and especially on appendages, and from M. electrina by the shape of propodeal spines, which are straight and strongly divergent in M. eocenica vs. curved down along their length and weakly divergent. Finally, Myrmica saxonica differs from the latter by the not pointed upper lateroventral corners of the head and by shorter propodeal spines that are strongly widened at the base, massive and somewhat curved inwards.

Keys including this Species

• Key to Myrmica fossils
• Key to Myrmica of European ambers

Distribution

This taxon was described from Baltic amber, Baltic Sea region, Europe (Bartonian, Middle to Late Eocene) and is also known from Danish-Scandinavian amber (Bartonian, Middle to Late Eocene) (Perkovsky, 2016).

Myrmica eocenica was originally described base on a single worker from Baltic amber, and later Radchenko (2023) found two workers belonging to this species in Baltic and Scandinavian ambers.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

• †eocenica. †Myrmica eocenica Radchenko, Dlussky & Elmes, 2007: 1497, figs. 4, 5 (w.) BALTIC AMBER (Eocene). See also: Radchenko & Elmes, 2010: 653.

Type Material

• Holotype worker, complete specimen, Baltic amber, No. 964/479 (PIN).

Type locality: Russia, Kaliningrad Prov., Baltic amber; Denmark, Scandinavian amber; both late Eocene, Priabonian age, 37.8–33.9 Ma.

References

• Perkovsky, E.E. 2016. Tropical and Holoarctic ants in late Eocene ambers. Vestnik zoologii 50(2): 111–122 (doi:10.1515/vzoo-2016-0014).
• Radchenko, A. 2023. Myrmica ants (Hymenoptera: Formicidae) in Late Eocene European ambers. Annales Zoologici 73(4), 629-648 (doi:10.3161/00034541anz2023.73.4.006).