Kempfidris, Fernández & Feitosa & Lattke, 2014

Fernández, Fernando, Feitosa, Rodrigo M. & Lattke, John, 2014, Kempfidris, a new genus of myrmicine ants from the Neotropical region (Hymenoptera: Formicidae), European Journal of Taxonomy 85, pp. 1-10 : 3-5

Kempfidris gen. nov.

Figs 1–3

urn:lsid:zoobank.org:act:B9B9FBA4-E0A5-44A2-BDD1-3C9ADA644AD9

Type species

Monomorium inusuale Fernández, 2007

Etymology

It is with great pleasure that we dedicate this new genus to Father Walter W. Kempf (1920–1976) ( Fig. 4 ) for his brilliant, but somewhat short career in ant taxonomy, with special reference to the Neotropical fauna. Besides the many monographs and descriptions of new taxa, Kempf provided the first catalog of Neotropical ants ( Kempf 1972), an obligate reference (until recently) for generations of myrmecologists.

Description (worker)

Antenna 12-segmented, with a well-defined 3-segmented club. Eye reduced to almost indistinct ommatidia, placed just anteriorad of head midlength. Frontal carinae and antennal scrobes absent. Mandible with four teeth: three apical teeth separated from isolated basal tooth by large diastema. Palpal formula 2,1. Clypeus projected anteromedially to form truncate lobe, lobe laterally bluntly angular and medially weakly concave, with distinct median seta and several surrounding setae. Median lobe of clypeus strongly bicarinate, carinae defining elevated area that converges posteriorly to form narrow strip between frontal lobes. Pronotum with anterolateral crest that extends dorsally, delimiting narrow anterior portion of pronotum. Metanotal groove very deep, well-marked. Bulla of metapleural gland large. Propodeum unarmed, declivity surrounded dorsolaterally by a crest, higher laterally than dorsally and joining the small metapleural lobe. Posteromedian portion of abdominal tergum VI and anteromedian portion of abdominal tergum VII with several minute, cylindrical micro-pegs, each bearing a hair on apex, though apparently broken in some.

Remarks

Kempfidris inusualis comb. nov. was provisionally described in Monomorium ( Fernández 2007) , but with many doubts due to the poor state of knowledge of the internal relationships in Myrmicinae . Fernández commented on a suggestion by Barry Bolton (pers. comm.) that K. inusualis comb. nov. might be a member of Stenammini due to its overall resemblance with members of that tribe. Traits of the frontal lobes and toruli, as well as the clypeal posterior border, would place K. inusualis comb. nov. in the Stenammini as diagnosed in Bolton (2003: 58). However, the first gastral tergite clearly overlaps the first sternite on its ventral surface, and the presence of a single medial clypeal seta indicates that the taxon belongs in the Solenopsidini , again sensu Bolton (2003: 59). We presently prefer to leave Kempfidris gen. nov. as an incertae sedis genus within the Myrmicinae until Ward and collaborators publish the conclusions, including a tribal arrangement, of their ongoing research (P.S. Ward, pers. comm.).

A reconsideration of this species, given the series of unusual characters it has compared to other myrmicines, argues for recognising it as a distinct lineage. Leaving it in Monomorium only increases the difficulties of defining a monophyletic Monomorium , thus confounding the present situation within those groups. The strongly reduced eyes and the long diastema between the three apical teeth and the basal tooth do not appear to be common in myrmicines. Kempfidris gen. nov. is reminiscent of Cryptomyrmex regarding the mandibular configuration (four teeth with a diastema), clypeal structure (elevated median area), single median seta along the anterior clypeal margin, and reduced number (2) of maxillary palp segments. However, Cryptomyrmex has a different antennal structure (12 segments, the last two forming a club), modified hairs along the mandibular masticatory margin and subcutaneous ommatidia. Reduced eyes can be found in the African fossulatum -group of Monomorium ( Bolton 1987) , as well as in Carebarella .

The most outstanding feature of Kempfidris gen. nov. is the series of minute, hair-bearing tubercles or cylindrical pegs on the abdominal apex. Most are concentrated on the anteromedian portion of the pygidium and some on the posteromedian portion of abdominal tergite VI, a position that would coincide with the position of the pygidial gland, which opens between abdominal tergites VI and VII ( Billen 2009). The structure of the micropegs with their associated hairs also hints at some sort of glandular function, or possibly a mechano-reception function during stinging, but a more convincing explanation will only be possible after a histological study. Whatever the function of these tubercles, they appear to be an autapomorphic structure, absent in other Myrmicinae and probably in other ants as well. In ants, the most structurally similar cuticular projections can be found throughout most of the body of some species in the formicine genus Echinopla Smith, 1857 , except on the pygidium, and additionally on the gastral apex of an undescribed species of Strumigenys Smith, 1860 ( Myrmicinae : Dacetini ). Given that these aforementioned taxa are not closely related to Kempfidris gen. nov., their structures are probably not homologous, but perhaps convergent evolution could be considered, especially in the case of the dacetine ant. Other specialized pygidial structures found in ants are the denticles or spines of Cerapachyinae and the large, upward-curving teeth in Pachycondyla crassinoda (Latreille, 1802) workers, but their position and form are very different. Most members of the solenopsidine group are smooth, with little sculpturing, but this species presents a moderate amount of sculpturing on the head, mesosoma, petiole and postpetiole.

Figures

Fig. 1. Kempfidris inusualis (Fernández, 2007) comb. nov., worker from Benjamin Constant, Amazon, Brazil (ICN). SEM photographs. A. Head in full face view. B. Head in dorsal oblique view. C. Mesosoma in lateral view. D. Apex of metasoma showing the cylindrical micro-pegs.

Fig. 2. Kempfidris inusualis (Fernández, 2007) comb. nov., worker from Porto Velho, Rondônia, Brazil (DZUP). High-resolution images. A. Head in full face view. B. Body in dorsal view. C. Body in lateral view.

Fig. 3. Kempfidris inusualis (Fernández, 2007) comb. nov., worker from Maroa, Amazonas, Venezuela, specimen CASENT0217050. High-resolution images from AntWeb. A. Head in full face view. B. Body in dorsal view. C. Body in lateral view. Images by Erin Prado.

Fig. 4. Father Walter Kempf (1920– 1976). Photographer unknown; files of the Franciscan Order in São Paulo, Brazil. Available from the Global Ant Project website: http:// gap.entclub.org/taxonomists/Kempf/ index.html