On Friday I gave you a different mystery object to the one I had originally planned, after my memory stick let me down. Nonetheless, it seems to have been an interesting one given the number of questions.

The first correct identification by Robert Grant was cleverly phrased, so as not to give the game away. Indeed, it seems as though the allusion to the song Alouette led many people off down the wrong track, due to its reference to skylarks. This combined with the object’s similarity to the shape of a whistle, identified early on by Jake, brought many of you to the conclusion that the object was a used as a musical instrument, whistle or game calling device. The string attached to the specimen certainly offers support that this object served a functional role for humans, although it may simply be part of the mounting for the original display of this object.

As it turns out, the reference to Alouette was a phonetic rendering of the taxonomic name for the genus to which this specimen belongs, which is Alouatta Lacépède, 1799 or what is commonly known as a Howler monkey – as Dave Godfrey punfully alluded to when he also worked out that the object was the hyoid of one of these South American primates. I am uncertain of the species, as there are eight within the genus and I don’t have enough comparative material to make a species level identification. In fact, I’m not even sure it’s possible to differentiate between species using the hyoid bone.

I’ve discussed the hyoid of howler monkeys before, in the answer to a past mystery object (#20), where I mention that the hugely inflated hyoid bone of these monkeys functions as a resonating chamber. It is closely connected to the voice box or larynx (a very near miss suggested by cromercrox) and it allows Howlers to make a huge amount of noise. The hyoid is unusual in that it is not articulated to any other bone and although it is positioned in the neck it is not related to the vertebrae (a possibility raised by Bob O’H). Instead, the hyoid shares a similar developmental process to the mandible and it is originally derived from pharyngeal arches, which are equivalent (homologous) to the gill arches of fish. The hyoid serves a very important function since it is what the tongue and larynx are attached to (that goes for all land vertebrates including humans, not just Howler monkeys).

Because of the function of this bizarre bone in the Howlers I may have been a bit cagey about giving a straight answer as to the role of the object in music – it is hugely important in sound production in the living animal, but I don’t think it is used in that way by humans. However, I wouldn’t be surprised if the hyoid was used as a drinking vessel or some kind of pouch by the South American native people’s who hunt the Howlers for food. Nature seldom makes such conveniently shaped pouches from bone, so it seems likely that they would be utilised by people with access to them.

This Friday I have something a bit special for you, to celebrate the first anniversary of the mystery object, so don’t miss it!