Amblyoponinae Forel, 1893

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 : 17-22

Amblyoponinae Forel, 1893

Fig. 6G

Amblyoponinae Forel, 1893: 195 (as subfamily of Formicidae ). Type genus: Amblyopone .

For taxonomic synopsis of Amblyoponinae , see AntCat (2014).

Synapomorphies

The Amblyoponinae was diagnosed by Bolton (2003) based primarily on the female castes, while more recently Yoshimura & Fisher (2012a) diagnosed the males for the Malagasy region. Apomyrma and Opamyrma violate most of these characters; these violations are noted below. Synapomorphies of the Amblyoponinae from the two aforementioned resources are as follows, with respective pleisiomorphies presented in brackets:

1. Dentiform clypeal setae present on anterior clypeal margin (all adult castes) (note 1). [Dentiform clypeal setae absent.]

2. Metapleural gland orifice directed more-or-less posterodorsally (female castes) (note 2). [Metapleural gland orifice directed laterally.]

3. Helcium supraaxial, thus petiole situated high on abdominal segment III, petiole without distinct posterodorsal face and abdominal tergum III without distinct anterodorsal face (all adult castes) (note 3). [Helcium infraaxial.]

4. Petiole very broadly attached to abdominal segment III (all adult castes) (note 4). [Petiole narrowly attached to abdominal segment III.]

5. Helcial sternite very wide (all adult castes) (note 4). [Helcial sternite narrow.]

6. Abdominal segment IV tergosternal fusion present (all adult castes) (note 5). [Abdominal segment IV tergosternal fusion absent.]

7. Basivolsella with ventroapical process, near bases of cuspis and digitus (male) (note 6). [Apical process of basivolsella absent.]

Fig. 5. Male morphology. A–C, F–I. Metasoma, lateral view. D–E. Head capsule, frontal view. — A. Myrmica latifrons (U.S.A., CASENT0104816, A. Nobile). B. Pseudomyrmex indet. (Mexico, CASENT0103327, A. Nobile). C. Nothomyrmecia macrops (Australia, CASENT0902784, Z. Lieberman); note that abdominal segment III is reduced relative to, but not differentiated from segment IV. D. Myrmecia pilosula (Australia, CASENT0902800, Z. Lieberman). E. Tetraponera indet. (Madagascar, CASENT0053316, A. Nobile). F. Tatzuidris tatusia (Panama, CASENT0178870, E. Prado). G. Acromyrmex volcanus (Costa Rica, INBIOCRI001283114, E. Ortega). H. Platythyrea arthuri (Mayotte, CASENT0132466, E. Prado). I. Formica pallidefulva (U.S.A., CASENT0172882, A Nobile). Scale bars: A–F = 0.5 mm, G–I = 1.0 mm.

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Notes on synapomorphies

1. Generally present in males, although these setae may be difficult to ascertain or absent in very small species. Not present in any other extant ant taxon, although present in most † Sphecomyrminae . Apomyrma and Opamyrma workers and Apomyrma males lack dentiform clypeal setae (the male of Opamyrma is unknown); rather, the workers have dentiform setae on the labrum. The male of Apomyrma has a very reduced labrum which lacks dentiform setae.

2. Males with or, more often, without metapleural gland orifice. The metapleural gland of Apomyrma was not evaluated in this study due to insufficient magnification.

3. This corresponds to the third, fifth, and sixth amblyoponine synapomorphies of Bolton (2003). Apomyrma workers and males have infraaxial helcia, while the worker of Opamyrma has an axial helcium.

4. Petiole very narrowly attached in worker Apomyrma and Opamyrma . The petiolar conformation of the male of Apomyrma , though broad, still differs from that observed in Amblyoponinae (see note 5).

5. Reversed in Adetomyrma female castes and variable in males ( Yoshimura & Fisher 2012a).

6. Character from Yoshimura & Fisher (2012a) and confirmed here via dissection of Amblyopone , Myopopone , Onychomyrmex , Paraprionopelta , and New World Stigmatomma .

Comments

The supraaxial helcium serves to distinguish both female and male Amblyoponinae , excluding Apomyrma and Opamyrma , from the majority of the Formicidae . Besides occurrence in the amblyoponines, the supraaxial state of the helcium is only developed in Acanthostichus (Dorylinae) and male Proceratium (Proceratiinae) , and weakly in the workers of Martialis (Martialinae) and the male of Tatuidris (Agroecomyrmecinae) . Males of three amblyoponine genera ( Bannapone , Concoctio , and Opamyrma ) remain unknown.

The Amblyoponinae was only recently split from the Ponerinae sensu lato ( Bolton 2003) and has been recovered in all molecular phylogenies as poneroids, with uncertain relationship to the Proceratiinae and the remainder of the group ( Brady et al. 2006; Moreau & Bell 2013; Ward 2014). Two main clades are recovered in the Amblyoponinae , termed the XMAS ( Xymmer , Myopias , Adetomyrma , Stigmatomma ) and OCP ( Onychomyrmex , Concoctio , Prionopelta ) clades ( Yoshimura & Fisher 2012a). Apomyrma , in its original description ( Brown et al. 1971), was proposed to be closely related to the Amblyoponinae (then Amblyoponini ), a contention supported by Wheeler & Wheeler (1985) and Hölldobler & Wilson (1990). Other authors demurred, placing the genus in its own tribe ( Apomyrmini ) in the Ponerinae sensu lato ( Dlussky & Fedoseeva 1988) and in the Leptanillinae ( Bolton 1990b; Kugler 1992), and eventually in its own subfamily, Apomyrminae ( Baroni Urbani et al. 1992; Bolton 1994, 2003). The “ Apomyrma ” sequences used by Saux et al. (2004) were contaminated (P.S. Ward, pers. comm.), but fortuitously their transfer of Apomyrma to the Amblyoponinae was supported by subsequent studies ( Brady et al. 2006; Moreau & Bell 2013). This classification is followed here.

Figures

Fig. 6. Male morphology. A–B, E–G. Head capsule in frontal view. C–D. Mesosoma, lateral view. H–I. Petiole, ventrolateral view. — A. Probolomyrmex indet. (Madagascar, CASENT0080551, A. Nobile). B. Anochetus boltoni (Madagascar, CASENT0063847, A. Nobile). C. Leptanilloides gracilis (Guatemala, CASENT0234561, M. Borowiec). D. Odontomachus simillimus (Seychelles, CASENT0172666, A. Nobile). E. Platythyrea arthuri (Mayotte, CASENT0132466, E. Prado). F. Protanilla indet. (Thailand, CASENT0119776, A. Nobile). G. Stigmatomma indet. (Madagascar, CASENT0007087, E. Prado). H. Nothomyrmecia macrops (Australia, B. Boudinot). I. Neoponera cf. apicalis (Honduras, B. Boudinot). Scale bars: A, F–G= 0.1 mm, B = 0.2 mm, C = 0.25 mm, E, H–I = 0.5 mm, D = 1.0 mm.