Eocenomyrma orthospina, Dlussky et Radchenko

Radchenko, A. G. & Dlussky, G. M., 2016, Further Data On The Extinct Ant Genus Eocenomyrma (Hymenoptera, Formicidae), Vestnik Zoologii 50 (5), pp. 395-406 : 405-406

E. orthospina

M a t e r i a l e x a m i n e d. Two workers:

1) Baltic amber, CGC F-6800.

Measurements (in mm): HL 0.69, HW 0.60, FW 0.27, FLW 0.31, SL 0.46, ML 0.75, PnW 0.75, PL 0.31, PW 0.23, PPL 0.21, PPW 0.30, ESD 0.27, total length ca. 3.0.

Indices: HL/HW 1.15, FW/HW 0.45, FLW/FW 1.15, SL/HL 0.67, SL/HW 0.77, PL/HL 0.45, PPL/HL 0.30.

2) Rovno amber, SIZK K-7026 (specimen damaged, without petiole, postpetiole and gaster).

Measurements (in mm): HL 0.66, HW 0.57, SL 0.52, FW 0.23, FLW 0.26, AL 0.85, PnW 0.39, ESL 0.31, ESD 0.30, HTL 0.52, total length ca. 3.5 (by analogy of ML+HL compare to other species).

Indices: HL/HW 1.16, SL/HL 0.79, SL/HW 0.91, FW/HW 0.46, FLW/FW 1.13, ESL/ HL 0.47, ESL/HW 0.53.

A key for the identification of Eocenomyrma species

1. Head, mesosoma and waist only densely punctated, without rugosity or reticulation ( fig. 7 ). Scape relatively very short, SL/HL 0.52, SL/HW 0.57. Petiole with very short peduncle, PL/ PH 1.13, its anterior surface steep, very slightly concave, meets with dorsal surface of node at an acute angle, dorsal plate short ant strongly declined posteriorly so that petiole seems cuneiform (seen in profile) ( figs 8 , 10 ). ..... ................................................................................................................................................ E. breviscapa sp. n.

– Head, mesosoma and waist longitudinally rugose or reticulated; petiole of another shape, but in any case with much longer peduncle, PL/ PH > 1.25 ( figs 5 , 6 , 12–17) Scape distinctly longer, SL/HL> 0.58, SL/HW> 0.70. ..................................................................................................................................................... 2

2(1). Gyne: propodeal spines relatively short (ESL/HL 0.17), straight, slightly widened at the base; head dorsum and mesosoma mostly longitudinally rugose, coarse reticulation presents on occipital area of the head ( figs 5 , 6 ). ...................................................................................................................... E. ukrainica sp. n.

– Workers: propodeal spines longer (ESL/HL> 0.23), more widened at the base, often curved down along their length, if straight, then much longer, ESL/HL> 0.35 ( figs 12–17 ). .................................................... 3

3(2). Head dorsum and mesosoma with longitudinal, slightly sinuous rugosity, without reticulation ( fig. 12 ) ......................................................................................................................................... E. rugosostriata (Mayr)

– Head dorsum and mesosoma at least partly with reticulation ( figs 13–17 )................................................ 4

4(3). Whole head dorsum and mesosoma with fine reticulation; petiolar node with well developed, flattened dorsal plate ( fig. 13 ). ............................................................................... E. elegantul a Dlussky et Radchenko

– Frons with longitudinal, slightly sinuous rugae, remainder part of head dorsum with coarse reticulation; petiolar node with rounded dorsum, without dorsal plate ( figs 14–17 ). ........................................... 5

5(4). Propodeal spines thin, not widened at the base, straight, directed backward and upward; petiole with very long peduncle (PL/ PH > 1.90) ( figs 14, 15 ). ............................... E. orthospina Dlussky et Radchenko

– Propodeal spines massive, widened at the base, slightly curved down along their length, directed mainly backward; petiole with much shorter peduncle (PL/ PH 1.27) ( figs 16, 17 ). ................................................. ...................................................................................................................... E. electrina Dlussky et Radchenko

Figures

Figs 7–8. Eocenomyrma breviscapa sp. n., photos of holotype worker: 7 — body in dorsal view; 8 — body in lateral view. Scale bar 1 mm.

Figs 9–11. Eocenomyrma breviscapa sp. n., line drawings of holotype worker made based on photos: 9 — body in dorsal view; 10 — body in lateral view; 11 — head in dorsal view (sculpture omitted). Scale bar 1 mm.

Fig. 5. Eocenomyrma ukrainica sp. n., photo of paratype gyne, body in lateral view. Scale bar 1 mm.

Fig. 6. Eocenomyrma ukrainica sp. n., line drawing of paratype gyne made based on photo, body in lateral view (sculpture omitted). Scale bar 1 mm.

Figs 12–13. Line drawings of Eocenomyrma rugosostriata (Mayr), neotype worker (12, body in dorso-lateral view) and E. elegantula Dlussky et Radchenko, holotype worker (13, body in lateral view). Scale bar 1 mm.

Figs 14–17. Line drawings of Eocenomyrma orthospina Dlussky et Radchenko, holotype worker (14 — head, mesosoma and waist, dorso-lateral view; 15 — mesosoma and petiole, lateral view) and E. eocenica Dlussky et Radchenko,holotype worker (16 — head,mesosoma and waist, dorso-lateral view; 17 — mesosoma and petiole, lateral view). Scale bar 1 mm.