Emeryopone Forel

Schmidt, C. A. & Shattuck, S. O., 2014, The Higher Classification of the Ant Subfamily Ponerinae (Hymenoptera: Formicidae), with a Review of Ponerine Ecology and Behavior, Zootaxa 3817 (1), pp. 1-242 : 194-196

Emeryopone Forel

Fig. 45

Emeryopone Forel, 1912: 761 (as genus). Type-species: Emeryopone buttelreepeni Forel, 1912: 762 ; by monotypy.

Emeryopone is a small genus (five described species) which ranges from Israel to Indonesia. Almost nothing is known about its habits, but its unusual mandibles suggest a specialized diet.

Diagnosis. Emeryopone workers are easily separated from most other ponerines by their long curved mandibles, which have five long teeth, the apical tooth greatly attenuated. The only genus with similar mandibles is Belonopelta , and to a much lesser extent Thaumatomyrmex . Emeryopone and Belonopelta can be separated by their frontal lobes (which are medium sized and separated anteriorly by a posterior extension of the clypeus in Emeryopone , and very small and closely approximated in Belonopelta ) and body sculpturing and pilosity (foveolate with abundant short pilosity and variable pubescence in Emeryopone , and pruinose without upright pilosity in Belonopelta ). Thaumatomyrmex has much longer mandibular teeth than Emeryopone , much more widely spaced frontal lobes, and larger eyes, among other differences.

Synoptic description. Worker. Small (TL 3.2–4.9 mm) ants with the standard characters of Ponerini . Mandibles long, narrow, with five teeth, the apical tooth greatly attenuated. Mandibles without a basal groove. Anterior clypeal margin convexly triangular. Frontal lobes small to moderate in size. Eyes small to very small, located far anterior of head midline. Metanotal groove absent or a vestigial suture. Propodeum broad dorsally. Propodeal spiracles round. Metatibial spur formula (1p). Petiole nodiform, the node rounded and wider than long. Subpetiolar process usually with a small lateral fovea near the anterior end. Gaster with a moderate girdling constriction between pre- and postsclerites of A4. Tergite of A4 moderately arched, the gaster mildly recurved. Head and body foveolate, with very light striations on the sides of the mesosoma and with abundant short pilosity and abundant to absent pubescence. Color ferruginous to black.

Queen. Described only for E. melaina: Similar to worker but slightly larger and alate, with three ocelli, larger eyes, and the modifications of the thoracic sclerites typical for winged ponerine queens ( Xu, 1998).

Male. Not described.

Larva. Not described.

Geographic distribution. Emeryopone has an unusual distribution, with collections known from Israel, India, Nepal, southern China, Indonesia, and Malaysia ( Baroni Urbani, 1975; Xu, 1998; Varghese, 2006; pers. obs.). Collections are rare and probably underestimate the true range of Emeryopone ( Baroni Urbani, 1975) .

Ecology and behavior. Basically nothing definite is known about the habits of Emeryopone . Based on their morphological characteristics and on collection data they are almost certainly cryptobiotic, and the rarity with which they are collected ( Baroni Urbani, 1975; Xu, 1998; Varghese, 2006) suggests a low population density, though this may be an artifact of inadequate collection methods, as apparently has been the case with Thaumatomyrmex (see under that genus). The extremely similar mandibular structure of Emeryopone and Belonopelta suggests a similar diet preference, and though the feeding habits of Emeryopone have not been reported, some Belonopelta feed to a large degree on diplurans. Emeryopone may have a similar diet specialization. The downcurved gaster of Emeryopone implies that it hunts in tight spaces.

Phylogenetic and taxonomic considerations. The proper taxonomic status of Emeryopone is somewhat uncertain. Forel (1912) described Emeryopone for the single species E. buttelreepeni but noted its similarity with Belonopelta , apparently separating it from that genus only by its lack of a medial tooth on the anterior clypeal margin (which is present in B. attenuata but not in B. deletrix , described later) and implicitly by its obsolete metanotal groove. Baroni Urbani (1975) later synonymized Emeryopone under Belonopelta , noting that those two characters are present in varying degrees in the other species he included in Belonopelta .

Baroni Urbani’s (1975) synonymizing of Emeryopone under Belonopelta is undermined by his taxonomic treatment of Belonopelta : he included both Simopelta and Emeryopone as junior synonyms of Belonopelta , while removing B. deletrix to the separate genus Leiopelta . Molecular evidence indicates that Emeryopone is not even sister to Simopelta and there is no morphological evidence to suggest otherwise. Further, P.S. Ward (pers. comm.) has found that Belonopelta belongs to the Pachycondyla group while Schmidt (2013) placed Emeryopone in the Ponera group. Thus it is seems clear that the morphological similarities between Belonopelta and Emeryopone are the result of convergence rather than close relationship.

Schmidt's (2013) molecular phylogeny of the Ponerinae places Emeryopone within the Ponera genus group as sister to the clade composed of Ponera , Ectomomyrmex , Cryptopone , Austroponera , Parvaponera and Pseudoponera . Morphological evidence suggests that Emeryopone may actually be sister to Ponera , as both genera share an overall similar gestalt and both have a fenestra in the subpetiolar process (absent in one Emeryopone species ). They differ most obviously in their mandibles and in the vaulting of A4. A sister relationship between Emeryopone and Ponera cannot be statistically rejected ( Schmidt, 2013).

Figures

FIGURE 45. Worker caste of Emeryopone buttelreepeni: lateral and dorsal view of body and full-face view of head (CASENT0104586, April Nobile and www.antweb.org); world distribution of Emeryopone.