I have often heard in the "gray" literature and from several informal statements by researchers that there has been some suggestion that hyaenodontid "creodonts" may eventually be found to be afrotherians, given that some of the oldest known hyaenodontids are from Africa and that this continent seems to have been the center of the group's diversity. However, searching through the literature I have not been able to track down any paper that suggests this. Does anyone know of any paper that has suggested a afrotherian placement for Hyaenodontidae?
Afrotheria comprises some species that arose in Africa but not all African mammals are Afrotherians. To include Hyenadontid mammals in Afrotheria one would have to find some morphological synapomorphies between the Creodonts and the Afrotheria. Last I knew creodonts were not ancestors of any of Afrotheria. Also Afrotheria itself is defined by molecular sequences alone - no morphological synapomorphies. Since we do not have any molecular data from fossil Creodonts, it is hard for me understand how someone could claim any affinity between Hyaenodontidae and Afrotheria.
I know that there is currently no morphological evidence to suggest that hyaenodontids are afrotherians, but I also know that some other authors have suggested such a relationship. I am just trying to find the appropriate references to show that there are a diversity of opinions on the affinities of hyaenodontids, but I cannot seem to find any reference to the "hyaenodontids are afrotherians" hypothesis in the literature.
Hi Russell,
Creodonta is supposed to be closely related to Carnivoramorpha, they are Laurasiatheria. Not sure who proposed Afrotheria hypothesis? Where did you hear about it?
Check this tree by Spaulding that is based on many morphological characters...http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0007062
The tree is pretty robust..also check the recent work of Sole' about new phylogenetic hypotheses within Creodonta.
You tend to see the "hyaenodonts as afrotherians" hypothesis posited all over paleontology sources on the web and in the informal literature, like Palaeos or some of the commenters on Tetrapod Zoology. Heck, even the Wikipedia page for hyaenodontids lists them as afrotherians! Although these sources are obviously not the best sort of places to get first-hand information about the relationships of extinct organisms, they had to have been getting the idea from somewhere, yet I cannot track down any reference that posits the idea. I am wondering if some have conflated an African origin for the Hyaenodontidae with the idea that hyaenodontids are members of the Afrotheria.
I am not a supporter of the hyaenodontids as afrotherians hypothesis, I am just trying to track down references to show that there has been a diversity of opinions as to exactly where "creodonts" go in the placental family tree.
Looking up a bit of the literature I stumble over a lot articles dealing with the tooth eruption sequence of hyaenodontids. There is also an interesting paper by Asher and Lehmann about afrotherian tooth eruption sequences (yes morphology in afrotherians studied as a group):
Asher, RJ, & Lehmann, T. 2008 Dental eruption in afrotherian mammals. BioMed Central (BMC) Biology 6: 1-11
This one is quoted in a lot hyaenodotid-tooth-papers, but non of the authors draws the conclusion that hyanodontids are afrotherians.
So no real help in your search, Russel, just some confirmation: it is mentioned in informal circles but no seems to have published about it ...
Dear Russell,
sorry but from the wikipedia in front of me I can clearly see that they are not classified as Afrotheria. Also informal references are no references for scientists. The fact that Creodonta possibly originated in Africa does not mean at all that they are Afrotherians...so pay attention to the relevant scientific literature and do not trust bloggers or anythign that is NOT peer reviewed!
The webpage below is correct:
https://it.wikipedia.org/wiki/Creodonta
Hi Carlo,
The Wikipedia entry you posted is for the Italian language version (and about Creodonta). Russel was referring to the English language version and the article about Hyaenodontidae:
https://en.wikipedia.org/wiki/Hyaenodontidae
(by the way, the German language version has an article Hyaenodontidae (which the Italian version does not) and this one classifies them as Laurasiatheria.)
https://en.wikipedia.org/wiki/Hyaenodontidae
@Meloro
Obviously such sources are not reliable. I was trying to see if there was any real grain of truth to the claims in the primary literature, because it seemed fishy to me.
Well done Russell. I would really like to know where the various popular science sites got hold of the idea too.
I don't think that Afrotheria is a particularly robust group anyway (the relationships among the families is not at all robust and one thinks that they could simply be a "wastebasket" -ala GG Simpson - group of oddball families. So to infer something so specific about fossils that is supported by molecular sequences from extant species seems more than fishy.
I agree with both of you, Russel and Patrice Showers Corneli, as long as Afrotheria is based solely on molecular data without any robust morphological synapomorphies it is not helpful to speculate about the placement of groups only known from the fossil record. (But of cause it still makes sense to include groups like the Moeritheriidae with obvious ties to extant afrotherian taxa in that group.)
Dear all,
apologies for my mistake and thanks for pointing the Hyaenodontidae wikipedia webpage.
This PlosOne paper (http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0089739) on Ocepaia can eventually help to solve the issue. Even if Hyaenodontidae are not presented, there is a good list of characters and their states accessible in the paper.
Good luck
Carlo
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