Last week I gave you this striking specimen to try your hand at identifying:

It’s the skeleton of a species that I’ve spoken about before and one for which I have a bit of a soft spot.

Several of you thought it was some kind of galliform (the group of birds including pheasants, quail, chickens, etc.), but although the size and general appearance of the bill is about right, it’s not one of them.

A few of you did however know what it was. Wouter van Gestel was first to recognise this as a Hoatzin Opisthocomus hoazin (Müller, 1776), with James Bryant and Cindilla Trent dropping some nice clues to show they were also in the know.

As it turns out, the original name for the Hoatzin was Phasianus hoazin because it looked so much like one of the Galliformes – and not just in the skeleton:

As you can see, these birds are quite striking, with colours and a crest that wouldn’t be out of place on a pheasant, but a lot of genetic and morphological research suggests that the Hoatzin is in a unique group, which diverged from the rest of the modern birds 64 million years ago, just after the non-avian dinosaurs went extinct.

Personally I think they are fascinating, with their clawed young that scramble around in dense vegetation, their limited ability to fly as adults and their unusual (for a bird) folivorous diet (that’s leaves) with associated bacterial fermentation tank crop. In fact, if any animal was on the road to becoming fire-breathing I think the Hoatzin may be it, with its ready access to methane and hydrogen sulphide belches – in fact I wonder if some spontaneous Hoatzin combustion due to these gasses gave rise to the myth of the Phoenix?