Martialinae

The only genus of this subfamily, Martialis, is monotypic. The enigmatic Martialis heureka is only known from Brazil.

Identification
Rabeling et al. (2008) - Worker diagnosis: small, blind, pale, presumably subterranean ants with the following combination of characters. Putative apomorphic conditions are marked by an asterisk. (1) Prementum partly visible with closed mouthparts, not entirely concealed behind the broad labrum and stipites; (2*) clypeus highly reduced; (3*) eyes absent; (4) frontal lobes absent; (5*) antennal sockets fully exposed and distant from each other, positioned at anterior margin of clypeus and projecting anteriorly beyond it; (6*) toruli raised vertically, forming cups to hold condylar bulbs; (7) antennae 12 segmented; (8) promesonotal suture present and flexible; (9) propodeal lobes absent; (10) metapleural gland orifice slit shaped, dorsal orifice margin projecting slightly forward, but not overhanging or concealing opening; (11*) metacoxal cavity closed, with a complete cuticular annulus surrounding the cavity; (12) metasternal process absent; (13*) petiole tergosternally fused, without a trace of a suture between tergite and sternite; (14*) abdominal segment III broadly attached to segment IV but distinctly smaller than the latter, tergosternally fused; (15) helcial tergite well developed, posterior part with a girdling constriction; (16) abdominal segment IV not tergosternally fused, posttergite broadly overlapping abdominal segment V; (17) stridulitrum on presclerite of abdominal segment IV absent; (18) spiracles of abdominal segments I–IV exposed, of V–VII concealed by preceding postsclerites; (19) pygidium (tergite of abdominal segment VII) well developed, simple, neither armed with teeth or setae nor heavily sclerotized nor otherwise modified; (20) sting present; (21) metatibial gland absent; (22) tarsal claws simple, without preapical teeth. Queen, male, and larva are unknown.

Nomenclature
MARTIALINAE [subfamily of Formicidae]
 * Martialinae Rabeling & Verhaagh, in Rabeling, Brown & Verhaagh, 2008: 14913. Type-genus: Martialis.

Boudinot (2015):

Apomorphies of Martialinae and Martialis

Note: Character states indicated here are generally apomorphic for the Formicidae given Bolton’s (2003) synthesis of plesiomorphies (appendix 3; presented below in brackets) and novel observations. These apomorphies may or may not be unique synapomorphies of M. heureka, but are of high diagnostic value. Worker-based states may also apply to the gyne, which at present is unknown. Larvae are unknown.

1. Mandibles more-or-less linear, elongate, not crossing at rest (worker), mandibles narrowly linear (male) (Fig. 11A–B) (note 1). [Mandibles triangular.]

2. Labrum with pair of trigger-hair-like setae at basolateral corners of sclerite, before margin curves distally, and situated at about lateral margin of lateral torular arch in anteroventral view; these setae directed dorsolaterally, contacting basal mandibular margin (worker) (note 2). [Labral trigger-hairs absent.]

3. Clypeus strongly reduced (worker) (note 3). [Clypeus well-developed.]

4. Medial clypeal portion covered with dense patch of erect, linear setae projecting anteriorly (worker) (note 3). [Dense setal patch absent.]

5. Antennal toruli exposed in dorsal view (worker) (note 4). [Antennal toruli partially concealed in dorsal view.]

6. Antennal toruli situated at and projecting anteriorly beyond anterior clypeal margin (worker) (note 5). [Antennal toruli distant from anterior clypeal margin.]

7. Antennal toruli situated anterior to line drawn between anterior tentorial pits (worker) (note 5). [Antennal toruli situated posterior to anterior tentorial pits.]

8. Antennal toruli dorsoventrally elongated (worker) (note 6). [Antennal toruli dorsoventrally short.]

9. Frons bulging medially posterior to posterior clypeal margin and between antennal toruli (worker). [Frons not bulging anteromedially.]

10. Compound eyes absent (worker) (note 7). [Compound eyes present.]

11. Petiole completely tergosternally fused, without externally visible suture (worker, male) (note 8) (Fig. 11C). [Petiole without tergosternal fusion.]

12. Abdominal segment III tergosternally fused (worker) (note 9).

13. Abdominal segment III reduced in size relative to segment IV, to which it is still broadly attached (worker) (note 10). [Abdominal segment III not reduced in size relative to segment IV.]

14. Abdominal segment IV presclerite differentiated from postsclerite (worker) (note 11). [Abdominal segment IV presclerite undifferentiated.]

Notes on diagnosis

1. Worker trait is character 1 of Rabeling et al.’s (2008) generic diagnosis.

2. The labrum of the worker is lateromedially broad, with the apical half populated by somewhat dense setae, while the basal half is glabrous except for a pair of elongate basolateral setae which are directed apicolaterally, toward the basal mandibular margins. These setae are reminiscent of the trigger-hairs of trap-jawed ants such as Strumigenys, the Daceton genus group, and the Odontomachus+Anochetus clade (although the setae of the ponerines occur on the mandibles). At first blush it seems unlikely that Martialis is a trap-jaw predator (Rabeling et al. 2008), as the most well-studied trap-jaw ants (Strumigenys, Daceton genus group, Odontomachus) all have mandibles, which are quite to very close-set compared to Martialis. This does not preclude mandibular snapping, however, as Mystrium (Moffett 1986; Gronenberg et al. 1998) and Protanilla (Hölldobler & Wilson 1990) have mandibles capable of rapid, forceful closure. While no apparent mandibular locking mechanism has been identified for Martialis, a detailed study of its internal morphology has yet to be done. The putative trigger setae of Martialis do not resemble the trigger setae found in Protanilla (Hölldobler & Wilson 1990).

3. Characters 3 and 4 above were treated as character 2 in the subfamilial diagnosis of Rabeling et al. (2008). Here they are considered independent.

4. Part of Rabeling et al. (2008) subfamilial character 5.

5. In addition to Martialis, the only ants with antennal toruli situated anterior to the anterior tentorial pits are homoplastically derived in the proceratiine genera Probolomyrmex and Discothyrea (Keller 2011).

6. Rabeling et al. (2008) character 6 of the subfamilial diagnosis.

7. Character 3 of Rabeling et al.’s (2008) subfamilial diagnosis.

8. Worker trait is character 13 of Rabeling et al.’s (2008) subfamilial diagnosis

9. Part of Rabeling et al. (2008) character 14 of the subfamilial diagnosis; tergosternal fusion of abdominal segment III may be an apomorphy of the poneroids.

10. Part of Rabeling et al. (2008) character 14 of the subfamilial diagnosis.

11. Generic diagnosis character 8 from Rabeling et al. (2008).

Additions to worker diagnosis of Rabeling et al. (2008)

Note: Characters indicated here are segregated from the “Apomorphies of Martialinae …” section above as they are of diagnostic value but are either plesiomorphies or of uncertain polarity, i.e., it is unclear whether these traits are apomorphic.

1. Scape conspicuously curved.

2. Meso- and metacoxae very closely situated (metapleuron foreshortened).

3. Metatibia with potentially glandular patch of discolored cuticle posterobasad ventroapical spur (note 1).

4. Aroliae reduced.

5. Petiolar peduncle anteriorly delimited by parabolic carina.

6. Subpetiolar process present as small anteroventral denticle.

7. Helcium axial.

8. AIII prora carinate, transverse, lip-shaped.

9. Anterior and posterior margins of AIII postsclerites not parallel in profile view, posterior margin of posttergite produced posteriorly.

10. Abdominal segments 4, 5, 6, and 7 about equal length.

Note

1. The potentially glandular patch of cuticle here identified is located on the apicoventral metatibial surface basad the tibial spur, in a similar position to the confirmed metatibial glands of other Formicidae. The cuticular patch was visible when backlit through the cleared leg of the holotype. Unlike the remainder of the leg cuticle, this patch was clearly thick and opaque. Recorded as absent by Baroni-Urbani et al. (1992), not recorded by Billen et al. (2013). Future specimens of Martialis workers should be subjected to detailed SEM and TEM study.

Comments

An attempt was made to discern the palpal count of the holotype worker, but the labrum is partially reflexed over the maxillolabial complex. It seems as if there are two maxillary palpomeres, but this could not be confirmed in any specimen orientation or lighting. The labial palps were not visible. Rabeling et al. (2008) recorded the propodeal lobes as absent in the worker; after comparative study of the male and worker it is apparent that weakly developed carinae are present in the area associated with propodeal lobes. These carinae are not obvious in perfect profile view. Their homology with propodeal lobes is uncertain.

Male diagnosis

Uniquely identified among the global fauna by the following character combination: mandibles linear, barely meeting at head midlength; clypeus reduced, with antennal toruli situated less than 1 antennal socket distance from anterior clypeal margin; notauli present; wing venation somewhat reduced, Ogata type IVa (five cells enclosed by tubular abscissae: costal, basal, subbasal, submarginal, and marginal cells closed); jugal lobe absent; petiolar tergum and sternum clearly fused; posterior petiolar foramen raised dorsad anterior foramen; helcium axial; abdominal segment III reduced relative to and differentiated from segment IV; abdominal segment IV with cinctus impressed yet indistinctly margined; pygostyles absent; and genitalia small, relatively unmodified.

1. Alate.

2. Mandalus enlarged (Fig. 11A–B).

3. Mandibles linear, lateral and medial margins weakly tapered to apex; barely meeting at head midline (Fig. 11A–B).

4. Palpal formula 2,1.

5. Clypeus reduced, greatest anteroposterior length about 1.5 times antennal socket diameter; antennal toruli separated from anterior clypeal margin by less than 1 antennal socket diameter (Fig. 11A–B).

6. Anterior clypeal margin without pegs (Fig. 11A–B).

7. Anterior tentorial pits situated posteromediad antennal toruli (Fig. 11B).

8. Frontal carinae and lobes absent (Fig. 11A–B).

9. Antenna 13-merous; funiculus filiform.

10. Occipital carina reduced, not enclosing occiput.

11. Notauli present, meeting medially and extending posteriorly to transscutal line (Fig. 11C–D).

12. Scutoscutellar sulcus not ribbed (Fig. 11D).

13. Oblique mesopleural sulcus present, anterior terminus separated slightly ventrad posterolateral pronotal corner (Fig. 11C).

14. Metapleural spiracular sclerite absent (Fig. 11C).

15. Propodeal lobes present, weakly developed (Fig. 11C).

16. Metacoxal cavities narrowly closed.

17. Tibial spur formula 1p,1p.

18. Pretarsal claws edentate.

19. Pterostigma indistinct, nearly absent (Fig. 12A).

20. Ogata forewing venation type IVa (Fig. 12A): Submarginal cell 1+2 closed by Rs+M+Mf2–3; 2rs-m present, Mf4–6 absent; marginal cell 1 closed; 1m-cu absent, thus discal cell 1 open; subdiscal cell 1 open.

21. Hindwing venation reduced (Fig. 12B): Only R+Rs and 1A tubular.

22. Jugal lobe absent (Fig. 12B).

23. Petiole nodiform, with indistinct posterior face; posterior foramen raised dorsally above longitudinal petiolar axis (note 1) (Fig. 11C).

24. Petiolar tergum with anterior parabolic carina (basipetiolar carina).

25. Petiolar tergum and sternum fused; laterotergite absent (Fig. 11C).

26. Petiolar tergum not forming anteroventral collar around sternum.

27. Helcium axial, broad (Fig. 11C).

28. Helcial sternite projecting ventrad lateral tergite margins.

29. Abdominal segment III weakly reduced relative to and differentiated from segment IV (Fig. 11C).

30. Prora of abdominal sternum III weak, transversely parabolic (Fig. 11C).

31. Abdominal tergum IV neither vaulted nor elongated relative to following segments (Fig. 11C).

32. Abdominal spiracle 4 exposed, 5–8 concealed by preceding tergites (Fig. 11C).

33. Abdominal sternum IX acutely triangular, apex nearly pointed; neither pronged nor toothed (Fig. 12C).

34. Pygostyles absent.

35. Genitalia small, partially exserted (Fig. 11C).

36. Cupula anteroposteriorly narrow along all faces (Fig. 12D–F).

37. Basimere continuous with telomere (Fig. 12D–H).

38. Telomere short, digitate, extending anteroventrad beneath basimere (Fig. 12F).

39. Cuspis absent (Fig. 12E).

40. Valviceps dorsomedially fused, lobate, longer than tall, apex downturned, two sides forming tube (Fig. 12D, H).

Note 1. The posterior petiolar foramen is convergently raised above the anterior petiolar foramen in Tatuidris (Agroecomyrmecinae).