10 year old Ian (our question man) has another question....
I have another question. Do you know if there have been any new fossil discoveries of desmostylans and/or sea cows in the past few years? I was wondering if desmostylans are more closely related to sea cows, elephants or hyraxes.
The latest studies of desmostylians indicate that they are more closely related to elephants than they are to hyraxes or sea cows. Within the placental mammal group Paenungulata (it includes hyraxes, sea cows and elephants), the desmostylians and elephants form a subgroup termed the Behemota, with the features that indicate their relatedness mostly being details of the teeth and ear region.
Another group - the obscure and poorly known anthracobunids - also appear to be members of Behemota (interestingly, anthracobunids are like desmostylians in being aquatic or amphibious. Given that elephants are also within this group, you might like to think what this tells us about the ancestry of elephants).
New fossil desmostylians and sea cows are published fairly regularly. One of the biggest discoveries within this area has been the 2001 publication of the Jamaican fossil sea cow Pezosiren - it is significant in that it still had hindlegs and could walk on land.