Archetype

Homology weekly: Prognathy

I am going to take advantage of figures I prepared for a talk I gave recently, where I had to explain a diagnostic characteristic of ants during the introduction. As I have mentioned before, ants are peculiar among wasps and bees in that their mouthparts are directed forward, rather than downward, in a condition known as prognathy (pro-, anterior, projecting; -gnathus, jaw).

Hypognathus condition in insects (left image from Wikimedia commons; right drawing modified after Snodgrass 1935)

› Continue reading

Tags: Foramen magnum, Hypognathy, Mouthparts, Prognathy

Not yet winter break for me

Forget the Friday winter break parties at the workplace, I’m stuck at home preparing slides for a short talk I’ll be giving on Monday. I’m not complaining though. This is the Portuguese meeting on evolutionary biology I mentioned earlier. The odd date (the 21st of December for the past four years) is to accommodate all the nationals pursuing Ph.D.s and postdocs abroad that come home during the holidays.

The meeting is organized by young researches, and this year will be specially interesting because there will be a discussion about creating a national society of evolutionary biologists.

I will be talking about the evolution of mouthparts within ants, covering some fascinating new discoveries that I haven’t share here yet but will blog about some time in the near future. In the mean time, here are a couple of my slides.

Media sources: antweb.org; Roberto Keller/AMNH.

Media sources: Wiki Commons; Alex Wild (http://www.alexanderwild.com/); R.E. Snodgrass 1935.

Tags: Meeting, Mouthparts, Prognathous

Homology Weekly: Mouthparts

Frontal part of the head in an Anochetus emarginatus worker, profile view (Scanning Electron Micrograph, Roberto Keller/AMNH)

This image shows the mouthparts of a trap-jaw ant in resting position. The only structures really visible are the prominent elongated mandibles (in yellow) that project forward. The rest of the pieces, laying immediately below, are retracted inside the preoral cavity.

› Continue reading

Tags: Anochetus emarginatus, Labium, Labrum, Mandibles, Maxillae, Mouthparts, Prognathous