Boloponera

Only a small number of specimens of this genus have been collected. Collection details in combination with morphological characteristics suggest the two species of Boloponera are cryptobiotic. While their diet is not known, their linear mandibles are suggestive of prey specialization.

Identification
Schmidt and Shattuck (2014) - Boloponera can be most easily diagnosed by the following unique combination of characters: mandibles linear, frontal lobes hypertrophied, eyes absent, head without posteroventral lamellae, propodeum with posterior lamellae, metafemora with longitudinal groove, mesotibiae and meso-/metabasitarsi without stout traction setae, relatively high helcium, and tergite A4 not arched. It bears significant similarity to Loboponera, Plectroctena, and Feroponera, but the characters above serve to differentiate it from all of these genera. Boloponera differs from Loboponera in having linear mandibles, loss of eyes, no posteroventral lamellae on the head, and a tubular tergite A4. It differs from Plectroctena in lacking a dorsal longitudinal groove on the mandibles, lacking excavations in the clypeus at the mandibular articulations, and lacking eyes. Boloponera can be separated from Feroponera by its linear mandibles, metafemoral grooves, and absence of traction setae on the middle and hind legs.

Fisher (2006) - Boloponera is reminiscent of Plectroctena. Both taxa have: (1) linear mandibles, (2) frontal lobes that project over mandible, (3) propodeal lamellae, and (4) metafemur with a longitudinal, possibly glandular groove. However, there are striking differences. The mandible of Boloponera lacks the characteristic large semicircular excavation in the clypeal margin at the mandibular articulation. Both taxa have linear mandibles, but Boloponera lacks the longitudinal groove on the inner half of the dorsal surface of the mandible blade.

In addition, Boloponera lacks the unique shape of the ventral anterior articulatory surface of the petiole found in the Plectroctena group. The Plectroctena group is characterized by the presence of a V-shaped groove or a narrow median pore-like depression on the anteriormost part of the ventral surface of the petiole (Bolton and Brown 2002). In Boloponera, the shape is similar to other Ponerini outside the Plectroctena group.

Boloponera differs from the only known Centromyrmex with elongate mandibles C. silvestrii by having frontal lobes that extend anteriorly and project out over the mandibular basal margins. In addition, Boloponera lacks the strong spines on the middle tibia and middle and hind basitarsi that characterize Centromyrmex. Boloponera is also superficially similar to Myopias but differs in lacking a second tibial spur and a clypeus that projects between the frontal lobes and extends over the basal margin of the mandibles. Based on overall characters, Boloponera along with Dolioponera may well constitute the sister group of the Plectroctena genus group. Centromyrmex may also prove to be closely related to the Plectroctena genus group.

Castes
Hawkes (2018) - The only known specimen of Boloponera vicans lacks eyes, as do three of the five known specimens of Boloponera ikemkha. The additional two specimens of the latter have moderately well-developed compound eyes with circa 15 ommatidia. These specimens are also relatively larger overall, are more stoutly built, and have larger gasters and longer legs. While these specimens may represent a distinct major worker caste they are more likely ergatoid queens. See the caste section of the B. ikemkha species page for additional discussion of Boloponera castes.

Nomenclature

 *  BOLOPONERA [Ponerinae: Ponerini]
 * Boloponera Fisher, 2006: 112. Type-species: Boloponera vicans, by original designation.

Hawkes (2018) - The discovery of a second species in the genus has confirmed the consistency of several characteristics, as well as enabling the recognition of new autapomorphies, that are of significance in elucidating relationships with other closely related genera, as discussed below.

The discovery of Boloponera ikemkha has confirmed several of the previously recognised differences between Boloponera and Plectroctena including:
 * 1. The lack in Boloponera of a highly modified mandibular articulation (incorporating differences in the structure of the mandibular articulation itself as well as of the clypeus and genae).
 * 2. The presence of both an apical and a preapical tooth on the mandible in Boloponera, as well as an additional tooth on the masticatory margin close to the basal tooth. Plectroctena have a blunt or truncated mandible with neither an apical nor a preapical tooth and, when present, the masticatory margin tooth is widely separated from the basal angle or tooth.
 * 3. The absence in Boloponera of a longitudinal groove on the inner half of the dorsal mandibular surface running parallel to the masticatory margin.
 * 4. The absence of a mesofemoral gland in Boloponera.
 * 5. The differing form of the anterior disc of the petiole in Boloponera.

Boloponera and Loboponera are similar with respect to petiole articulation, the expansion of the torular lobes, orientation of the clypeal surface, mandibular articulation and absence of a dorsal groove on the mandible. Loboponera and Plectroctena are similar in having the torular lobes not overhanging the mouthparts, configuration of clypeal setae, presence of a mesofemoral gland, position of the metapleural gland opening, development of the prora and degree of arching of A4. Plectroctena and Boloponera are similar in the absence of posterolateral head flanges and shape of the mandibles, although the latter may not be equivalent in view of the extreme development of other mandibular characters in Plectroctena. Thus there appear to be fewer characters suggesting a close relationship between Boloponera and Plectroctena than there are linking Boloponera with Loboponera or Loboponera with Plectroctena; this assessment implies that Boloponera and Plectroctena are less similar to each other than either is to Loboponera, suggesting an intermediate position for the latter. The characters discussed above strongly support the retention of Boloponera as distinct from Plectroctena and suggest that Boloponera is sister to Loboponera and Plectroctena rather than being closer to or even nested within Plectroctena.

Worker
Worker. Ponerinae ant with the characters of the Ponerini tribe listed in Bolton (2003) and also with the following:

1. Median portion of clypeus not extended anteriorly as a lobe that projects out over the mandibular basal margins.

2. Frontal lobes extend anteriorly and project out over the mandibular basal margins.

3. Labrum not visible in full-face view with mandibles closed.

4. Mandible linear, without large semicircular excavation in clypeal margin at mandibular articulation.

5. Postventral curve of head in profile without projecting curved flange.

6. Propodeal dorsum without median longitudinal groove or impression.

7. Metafemur with longitudinal (glandular) groove present along entire length.

8. A4 tergite tubular, not strongly arched and down-curved.

9. Anteroventral process on the A3 sternite present, but greatly reduced.

10. Anteriormost part of ventral surface of petiole with broadly horseshoe-shaped strip of cuticle.

11. Antennae 12-segmented.

Hawkes (2018) - As in Fisher (2006), with the following additions and modifications:

1. Glandular structure present on metafemur, visible for approximately 2/3 of the length of the femur as a thinning of the cuticle, without any impression or groove. No such structure visible on mesofemur.

2. Anterior disc of petiole with a broadly C-shaped to horseshoe-shaped strip of thicker cuticle surrounding a roughly semicircular patch of thinner cuticle.

3. Anterior margin of clypeus with a strongly convergent pair of long setae that cross at approximately their mid length.

4. Posterior margin of clypeus projecting anterad of the anterior clypeal margin and overhanging the closed mandibles.

5. Mandible with an apical tooth plus three pre-apical teeth; the sub-apical tooth is close to the apical and is followed by a large diastema before the third tooth, which is located near the fourth (basal) tooth at the basal angle, near the mid-length of the mandible.

6. Metapleural gland orifice opening dorsally oriented, clearly visible in dorsal view but largely obscured in lateral view; posteriorly it is completely hidden by the upwardly extended ventral flap.

Schmidt and Shattuck (2014) - Small (TL 3.3 mm) robust ponerine ants with the standard characters of Ponerini. Mandibles linear, with two small teeth and a basal groove. Frontal lobes hypertrophied and and projecting beyond the anterior clypeal margin. Antennae with two-segmented club. Eyes absent. Mesopleuron divided by a transverse groove, the anepisternum appearing fused to the mesonotum and metapleuron. Metanotal groove absent. Propodeum broad dorsally, the posterolateral margins drawn out posteriorly into cuticular lamellae. Propodeal spiracles round. Metafemora with dorsal longitudinal groove. Metatibial spur formula (1p). Petiole nodiform, the subpetiolar process a posteriorly-directed tooth. Helcium projecting from near midheight on the anterior surface of A3. Strong constriction between pre- and postsclerites of A4 apparent. Head and body foveate and longitudinally striate, with abundant short pilosity and no pubescence. Color orange.