Euprenolepis

Witte and Maschwitz (2008) discovered that Euprenolepis procera are nomadic mushroom harvesters, a previously unknown lifestyle among ants.

Identification
Six diagnostic characters can generally separate Euprenolepis workers from the workers of other formicine genera: 1) basal tooth with a distinct obtuse angle on the inner mandibular margin, 2) apical tooth large and curved toward midline of body, 3) mandalus large and conspicuous, 4) medially clypeus without a prominent keel, 5) anterior clypeal margin medially emarginate, with a medially placed seta, and 6) widely spaced torulae. The reduced segmentation in the palps also helps in diagnosing the genus, except Pseudolasius also exhibits palpal segment reduction. With the exception of Euprenolepis negrosensis, all species appear to have a 3:4 palpal formula. Pseudolasius typically possess 2 or 3 labial palpal segments. Euprenolepis is most likely to be confused with Pseudolasius, however, with the exception of E. negrosensis, Euprenolepis have much larger eyes than Pseudolasius species. Additionally, the six characters listed above provide a means to separate the two genera. (LaPolla 2009)

Euprenolepis Species Key

Key to Prenolepis Group Genera

Distribution
Euprenolepis is endemic to southeastern Asia. Most species are presently known from Borneo only, but whether or not this reflects biological reality or collecting bias remains unclear. It is interesting to note that this distribution pattern is essentially the same as Cladomyrma, another Southeast Asian endemic formincine genus. (LaPolla 2009)

Castes
It remains unclear how widespread polymorphism is in the genus. Polymorphism is exhibited in Euprenolepis procera, with a minor and major worker caste clearly expressed. However, in no other known species is polymorphism observed. This may reflect collecting bias, because most species are only known from a few localities. However, at least one species, Euprenolepis wittei, has been collected from long nest series and polymorphism has not been found in the workers (V. Witte, pers. comm.). It is worth pointing out that despite E. procera being by far the most commonly encountered Euprenolepis in collections, majors are still relatively uncommon. (LaPolla 2009)

Nomenclature

 *  EUPRENOLEPIS [Formicinae: Plagiolepidini]
 * Euprenolepis Emery, 1906b: 134 [as subgenus of Prenolepis]. Type-species: Prenolepis procera, by original designation.
 * Euprenolepis subgenus of Paratrechina: Emery, 1925b: 223.
 * Euprenolepis raised to genus and senior synonym of Chapmanella: Brown, 1953h: 6.
 * CHAPMANELLA [junior synonym of Euprenolepis]
 * Chapmanella Wheeler, W.M. 1930d: 41. Type-species: Chapmanella negrosensis, by original designation.
 * Chapmanella junior synonym of Euprenolepis: Brown, 1953h: 6.

Description
LaPolla 2009:

Worker
(minors and majors): 1) Medium sized (measured in this study between 2.9–6.25 mm in total length) yellow to dark brown formicine ants.

2) Euprenolepis procera known to be polymorphic with a minor and major worker castes, unclear if other species are also polymorphic.

3) Antennae 12 segmented; torulae widely separated from each other, not touching posterior clypeal margin.

4) Scapes long, always surpassing posterior margin, and with scattered erect setae.

5) Eyes generally large (one known exception Euprenolepis negrosensis), near midline of head.

6) Mandibles broad with 5 teeth; basal tooth with an obtuse angle on the inner mandibular margin (one known exception E. negrosensis, where basal tooth is usually roughly quadriform relative to inner mandibular margin); apical tooth large and curved toward midline of body.

7) Mandalus large and conspicuous.

8) Maxillary palps 3-segmented; labial palps 4-segmented (except in E. negrosensis which has 4 segmented maxillary palps).

9) Clypeus broad, slightly convex medially, flattening anteriorly; median clypeus without a prominent keel.

10) Anterior clypeal margin medially emarginate, with a medially placed seta.

11) Mesosoma elongate with mesothorax constricted immediately behind pronotum; propodeum high and domed-shaped.

12) Scattered erect setae across entire body.

Queen
(queens are only known from three species, Euprenolepis negrosensis, Euprenolepis procera, and Euprenolepis wittei, so this list must be considered provisional):

1) Generally as in worker with modifications expected for caste.

2) Eyes large; ocelli well developed and prominent.

3) Body covered in a dense layer of pubescence.

Male
(males are only known from three species, E. negrosensis, E. procera, and E. wittei, so this list must be considered provisional):

1) Eyes large, occupying more than half the lateral portion of the head; ocelli prominent.

2) Scapes long, surpassing posterior margin by at least first 3 funicular segments; 13-segmented antennae.

3) Anterior clypeal margin emarginate, as in workers; margin curls up slightly.

4) In Euprenolepis procera, and Euprenolepis wittei mandibles broad with only apical tooth well-developed, remainder of inner mandibular margin smooth, with a distinct basal angle. In E. negrosensis, mandibles broad, with 4 teeth; all but apical teeth are weakly developed.

5) Mesosoma modified as expected for flight muscles; propodeum indistinct.

6) In E. procera and E. wittei, penis valve apodemes terminate dorsally; in lateral view, penis valves project dorsally above parameres; digiti anvil-shaped (weakly anvil-shaped in E. negrosensis), ventrally directed.

7) Digiti and cuspi meet dorsolaterally, about halfway along length of digiti.

8) Parameres and terminal gastral segments with abundant, long setae; apices of parameres bend towards the midline of the body.

Additional References

 * LaPolla, J. S. 2009. Taxonomic revision of the Southeast Asian ant genus Euprenolepis. Zootaxa. 2046:1-25.


 * Witte,V. & Maschwitz, U. (2008) Mushroom harvesting ants in the tropical rain forest. Naturwissenschaften, 95(11), 1049–54.