Apomyrma Brown, Gotwald Jr. & Lévieux, 1971

Boudinot, Brendon E., 2015, Contributions to the knowledge of Formicidae (Hymenoptera, Aculeata): a new diagnosis of the family, the first global male-based key to subfamilies, and a treatment of early branching lineages, European Journal of Taxonomy 120, pp. 1-62 : 22-24

Apomyrma Brown, Gotwald Jr. & Lévieux, 1971

Apomyrma Brown, Gotwald & Lévieux, 1971: 259 . Type-species: Apomyrma stygia , by original designation. Monotypic.

Apomorphies of Apomyrma

Note: Characters here indicated are apomorphic for the Formicidae generally, given Bolton’s (2003) synthesis of plesiomorphies and novel observations.

1. Raised clypeal disc between antennae lateromedially compressed, forming wedge-shaped process in anterolateral view, posterolateral clypeal margins distant from antennal toruli (female castes) (note 1). [Clypeal disc broad, uncompressed.]

2. Axillae enlarged, meeting medially (male). [Axillae small, not meeting medially.]

3. Transverse sulcus posterior to helcial sternite present (female castes). [Transverse sulcus posterior to helcial sternite absent.]

4. Abdominal segment III posttergites unfused (all castes).

5. Spiracles of abdominal segment III enlarged and situated at extreme anterior margin of tergum in profile view (female castes) (note 2). [Spiracle smaller, situated distant from anterior tergal margin in profile view.]

6. Penisvalvae dorsally fused for most of length, and anterodorsally fused with basimeres (male). [Penisvalvae unfused dorsally, unfused with basimere.]

7. Anterior base of penisvalvar lateral apodeme strongly produced laterally, forming a helmet- or cowry-like bulbous structure. [Lateral apodeme nearly flush with to slightly raised from valviceps.]

Notes on apomorphies

1. Clypeus also lateromedially compressed in Leptanilla .

2. Although adduced as the sole synapomorphy for Apomyrma + Leptanillinae by Bolton (1990a), this may be a convergence, as the third abdominal spiracle of Opamyrma is considerably posterior to the anterior tergal margin in profile view.

Comments

The infraaxial helcium of the worker and male may be apomorphic, depending on placement of the genus.

Male diagnosis

Male Apomyrma are recognizable by the combination of nub-like mandibles, anteriorly elongate mesosoma, reduced wing venation (marginal, costal, discal, basal, subbasal cells closed; subdiscal cell 1 open; submarginal 1 closed or open; pterostigma absent; 2r-rs situated in basal half of wing), and small, wedge-shaped petiole which is broadly and infraaxially attached to abdominal segment III.

1. Alate ( Fig. 8 B–C).

2. Mandalus somewhat enlarged, but clearly ringed by sclerotized mandibular cuticle in dorsal view ( Fig. 8A ).

3. Mandibles strongly reduced, nub-like, lacking teeth ( Fig. 8A ).

4. Labrum strongly reduced, subrectangular.

5. Palpal formula 2,1, palps strongly reduced in size.

6. Antenna 13-merous; funiculus filiform.

7. Occipital carina absent ( Fig. 8 B–C).

8. Eyes situated anteriorly, malar area visible in profile view ( Fig. 8B ).

9. Oblique mesopleural sulcus absent ( Fig. 8B ).

10. Subalar sulcus broadly enlarged, larger than lower metapleural area ( Fig. 8B ).

11. Epimeron narrow, lamellar ( Fig. 8B ).

12. Metapleural spiracular plate absent ( Fig. 8B ).

13. Mesoscutum anteriorly elongated, with concomitant elongation of lateral pronotal face ( Fig. 8 B–C).

14. Notauli fine, shallowly impressed, nearly meeting at midline ( Fig. 8 B–C).

15. Axillae enlarged, meeting medially ( Fig. 8C ).

16. Scutoscutellar sulcus exceedingly fine ( Fig. 8C ).

17. Metapleural gland orifice conspicuous ( Fig. 8B ).

18. Propodeum small, convex ( Fig. 8B ).

19. Propodeal spiracle small, circular, situated in anteroventral sector of lateral propodeal face ( Fig. 8B ).

20. Propodeal lobe absent ( Fig. 8B ).

21. Ventrolateral meso- and metapleural margins ecarinate ( Fig. 8B ).

22. Velum of calcar absent.

23. Forewing lacking membrane anterior to costal vein ( Fig. 9A ).

24. Forewing venation Ogata type IVa: Submarginal cell, marginal cell 1, and discal cell 1 closed; subdiscal cell 1 open ( Fig. 9A ).

25. Forewing costal vein present, reaching 2r-rs ( Fig. 9A ).

26. Hindwing venation reduced, only R+Rs tubular ( Fig. 9B ).

27. Jugal lobe absent ( Fig. 9B ).

28. Petiole subsessile, conical, broadening posteriorly; posterior face weak; anterior and posterior foramina oriented along main body axis ( Fig. 8B ).

29. Petiolar tergum lacking anterior parabolic carina (basipetiolar carina).

30. Subpetiolar process absent ( Fig. 8B ).

31. Helcium infraaxial ( Fig. 8B ), broad in dorsal view.

32. Prora of abdominal sternum III absent ( Fig. 8B ).

33. Abdominal segment III undifferentiated from IV ( Fig. 8B ).

34. Cinctus between abdominal segment IV pre- and postsclerites absent ( Fig. 8B ).

35. Abdominal tergum VIII posterior margin parabolic, unmodified ( Fig. 8B ).

36. Abdominal sternum VIII visible in situ.

37. Abdominal sternum IX unmodified; neither pronged nor toothed ( Fig. 9C ).

Distribution of Apomyrma

Afrotropical, confirmed from: Côte d’Ivoire, Ghana, Benin, Nigeria, Cameroon, Central African Republic, Democratic Republic of the Congo (new record), and South Africa.

Figures

Fig. 8. Apomyrma CD01, male, photomicrographs (CASENT0086073, E. Prado). A. Head, frontal view. B. Body, lateral view. C. Body, dorsal view. Scale bars: A = 0.2 mm, B–C = 0.5 mm.

Fig. 9. Apomyrma CD01, male, photomicrographs. A. Forewing. B. Hindwing. C. Abdominal sternum IX, ventral view. D. Genital capsule, dorsal view. E. Genital valves, slightly splayed and without cupula, ventral view. F. Genital capsule, lateral view. G. Volsella and paramere, mesal view. H. Penisvalva in situ, mesal view. Scale bars: A–B = 0.5 mm, C–H = 0.1 mm. Abbreviations: see Material and Methods