Best Paper Award 2023

Reading Time: 4 minutes
Adrian Richter

In 2023, Myrmecological News awards for the sixth time the Best Paper of the previous year. From January 9 to January 23, the editorial board and the community could vote for their most favourite papers published in 2023.
It is now our great pleasure to announce the winner of the certificate of this Best Paper 2023 and the voucher worth the Article Processing Charge (700 EUR) of a future contribution in Myrmecological News:

“Wonderfully weird: the head anatomy of the armadillo ant, Tatuidris tatusia (Hymenoptera: Formicidae: Agroecomyrmecinae), with evolutionary implications” written by Adrian Richter et al.

A View by Adrian Richter

I am an insect morphologist from Germany and the current stage of my academic adventure is a postdoc in Okinawa, Japan with Evan Economo at OIST.
My fascination with ants began in my early childhood, so I am thankful and humbled that I am getting a chance to actually study them myself now. My journey in academia began in Jena, Germany, where I did a Bachelor’s, Master’s and PhD with Rolf Beutel.
If I had to summarize my aspirations as a researcher in three words, it would be to “understand ant bodies”. I am using techniques such as micro-CT scanning, electron microscopy and histology to look at the innermost and smallest details of ant anatomy. By comparing different ant species, I want to contribute to understanding how the immense diversity of ants we see on earth has evolved. Recently, I have been trying to incorporate more and more phylogenetic comparative methods in my research, which is mostly focused on the feeding system of ants at the moment. Apart from ants, one thing I really enjoy is Japanese culture  and it has been great to visit some of the ancient castles, temples and mountain forests during my time here.

Fig. 2: Volume renderings of the head of Tatuidris tatusia, based on micro-computed tomography scan. A: Dorsal view. B: Lateral view. C: Ventral view. D: Frontal view of oral foramen showing articular surfaces of the mouthparts. Abbreviations: al – atala; alf – atalar fossa of the pleurostoma; asc –antennal scrobe; ascf – stabilizing ridges in the antennal scrobe; ata – anterior tentorial arm; atp – anterior tentorial pit; ccl – clypeal condylar lobe; ccr – clypeal condylar rail; ce – compound eye; cl – clypeus; clg – clypeal groove; cll – clypeal lamina; fr – frontal area; frl – frontal lobe; hc – hypostomal cardinal condyle; hyc – hypostomal corner; hyg – hypostomal groove; hyl – anterior lobe of the hypostomal process; hysci – inner hypostomal carina; hyscou – outer hypostomal carina; hysp – triangular hypostomal process; lb – labrum; lcl – lateral clypeal lobe (fused to frontal lobe); md – mandible; mdc – mandibular condyle; oca – occipital carina; occ – occipital area; pgb – postgenal bridge; pm – prementum; pocn – postoccipital condyle; pta – posterior tentorial arm; ptp – posterior tentorial pit; sfp – subforaminal process; st – stipes; tb – tentorial bridge; to – torulus; vcb – posterolateral ventral cephalic bulge; vma – ventral mandibular articulation fossa; vt – area of the vertex. Symbols: cyan dotted line – outline of the hypostomal process lobe in D and rough indication of the clypeal margin in A. Color marking: cyan – clypeal condylar rail; purple – clypeal condylar lobe.

Tatuidris morphology
Our paper on the head of Tatuidris tatusia is part of a series of studies I did on ant head anatomy during my PhD project. It was especially fun to reconstruct the head anatomy of this South and Central American species from micro-CT data because it was in many ways very different from all the other ants that I had looked at before. Some of those “weird” features of Tatuidris are their cup-shaped mandibles with a dense brush of thick, spine-like setae and their deep antennal scrobes with antennal sockets that are turned upside down. This unique head shape is also related to some unusual internal features, like an almost right angle in the tentorium, an internal skeletal element that the antennal muscles sit on, which have to reach the upturned antennal socket. We also focused quite a bit on the mandibular articulation because this was, again, rather different from most other ants. Based on 3D-prints of the head and mandibles, we think that there are several stabilizing sliding surfaces that guide the mandible to open along two different axes. The 3D-prints we used to infer this are shown in Figure 11 of the article. Finally, we looked at some of the morphological characters that have been used to describe the different clades of poneroid ants and discussed some of those in the light of the most recent phylogenetic hypotheses. On the one hand, our study is a step on the way to better understand morphological evolution of poneroids and ants in general, and on the other hand, provides some new insights on an ant species so rarely studied, we don’t even know what it eats yet.

Fig. 9: Volume renderings of the digestive tracts, its muscles and glands, and the central nervous system of Tatuidris tatusia, based on micro-computed tomography scan. A: Dorsal view of digestive tract, select muscles, glands, and the nervous system. B: Ventral view of digestive tract, glands, and nervous system. C: Ventral view of cut open head capsule showing dorsal head muscles. D: Sagittal view of digestive tract, muscles, glands, and nervous system. E – G: Distal digestive tract with focus on prepharynx and oral arms. E: Dorsal view. F: Lateral view. G: Posteroventral view. Abbreviations: 0bu1 – M. clypeobucca¬lis; 0bu2 – M. frontobuccalis anterior; 0bu3 – M. frontobuccalis posterior; 0bu5 – M. tentoriobuccalis posterior; 0ci1a – M. clypeopalatalis, unpaired portion; 0ci1b – M. clypeopalatalis, paired portion; 0hy1 – M. frontooralis; 0hy2 – M. tentoriooralis; 0hy9 – M. oralis transversalis; 0lb2 – M. frontoepipharyngalis; 0pe1d – M. pharyngoepipharyngalis, dorsal portion; 0pe1dl– M. pharyngoepipharyngalis, lateral dorsal portion; 0pe1l – M. pharyngoepipharyngalis, lateral portion; 0ph2 – M. tentorio-pharyngalis; br – brain; bt – buccal tube; dhy – distal hypopharynx; ep – epipharynx; fg – frontal ganglion; fmo – functional mouth opening; ibp – infrabuccal pouch; lb – labrum; nan – antennal nerve; no – optical nerve; oa – oral arm; oal – oral arm lamella; oalw – oral arm lateral wall; oapr – oral arm process; ph – pharynx; phg – pharyngeal gland; pph – prepharynx; pphg – prepharyngeal gland; sog – suboesophageal ganglion; toa – torular apodeme.

That this study got enough appreciation in the myrmecological community to win the best paper award is incredibly humbling, and we are very thankful that our work has found an interested readership.

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1 Response

  1. Van der Stappen Marc says:

    Indeed, one of the best articles last year. Hoera!

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