Eldermyrmex exsectus

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Eldermyrmex exsectus
Temporal range: Bartonian, Middle to Late Eocene Bitterfeld amber, Sachsen-Anhalt, Germany
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dolichoderinae
Genus: Eldermyrmex
Species: E. exsectus
Binomial name
Eldermyrmex exsectus
Dubovikoff & Dlussky, 2019

A fossil ant from the Bitterfeld amber (Bartonian, Middle to Late Eocene)

Identification

E. exsectus differs from the type species of the genus by shorter head and scapus, the structure of the propodeum (the basal surface is much shorter than the declivous) and petiole (vertical high node).

Key to the species of the genus Eldermyrmex

  • Head long (CI 158), with subparallel sides and straight occipital margin. Basal surface of propodeum is more long than declivous (Pl. 1, figs. 1, 2). Petiole with small conical node inclined forward => Eldermyrmex oblongiceps
  • Head shorter (CI 120), with convex sides and deeply concave occipital margin. Basal surface of propodeum distinctly shorter than declivous. Petiole with high vertical conical node (Pl. 1, figs. 5, 6) => Eldermyrmex exsectus

Distribution

This taxon was described from Bitterfeld amber (Bartonian, Middle to Late Eocene).

Castes

Dubovikoff and Dlussky 2019. Figures 3-6. Eldermyrmex exsectus holotype MNKB, no. 11/206. Scale bar 1 mm. 3. top view. 4. bottom view. 5. side view. 6. structure of mesosome and petiole.

Nomenclature

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

  • exsectus. †Eldermyrmex exsectus Dubovikoff & Dlussky, 2019: 995, figs. 3-6 (w.) BITTERFELD AMBER (Eocene).

Type Material

Taxonomic Notes

This specimen is clearly visible but partially deformed. It seems may have been heated. Head and mesosoma with longitudinal cracks in the cuticle, the legs are slightly stretched and damaged. Petiole and abdomen are separated from mesosoma.

Description

Worker

mm: HL 0.79, HW0.66, EL 0.12, SL 0.52, VL 0.39, WL 0.84, PEL 0.17, F3 0.55, GL 1.19, TL 3, CI 120, EI 18, SI 66.

Body length about 3 mm. Head moderately short (CI 120) and wide, its length 1.2 times more than width, with convex sides and deeply concave occipital margin. Ocelli are absent. Eyes are small and shifted forward. Anterior margin of clypeus concave (slightly notched). Anterolateral angles of clypeus distinct. Mandibles triangular, massive, with short teeth (hard to see). Scapus short, does not reach occipital margin; its length is 1.25 times less than width of head. Flagella is not preserved. Mesosome narrow, noticeably narrower than head. Mesosomal seams well expressed, distinct. Mesonotum in profile, slightly raised above pronotum. Basal surface of propodeum distinctly shorter than declivous. Propodeum is compressed from the sides, its sides are almost vertical, with distinct lateral edges. Basal and declivous surfaces with shallow medial impression. Petiole with high vertical conical node. Body smooth and shiny, without standing hairs.

Type Material

Holotype. MNKB, no. 11/206, worker, Bitterfeld (Saxonian) amber, Late Eocene.

Etymology

From the Latin exsectus (carved).

References