[continued from previous message]   
      
   >>>>> years ago, and that is around 30 million years after that common   
   >>>>> ancestor's lineage split off from the horse lineage.  Plenty of   
   >>>>> time to reevolve claws.   
   >>>>   
   >>>> The relevant clawed clade is Ferae, not Carnivora. (To the best of   
   >>>> my knowledge miacids are not hooved; viverravids are not hooved;   
   >>>> oxyaenids are not hooved; hyaenodonts are not hooved; pangolins are   
   >>>> not hooved; and pantolestids are not hooved.) The consensus date for   
   >>>> Ferae is 65 million years ago. Wikipedia gives a date for 73-85   
   >>>> million years for Scrotifera, but the relevant nodes, depending on   
   >>>> topology, are Zooamata or Ferungulata, which are younger.   
   >>>>   
   >>>> As support for hooves as a convergent trait, not all mesonychians   
   >>>> (which are stem artiodactyls) possessed hooves. However there is   
   >>>> dispute whether the hoofless mesonychians (arctocyonids) are stem-   
   >>>> artiodactyls.   
   >>>   
   >>> It's also the case that not all (or any??) stem-perissodactyls are   
   >>> hooved, and even some crown-perissodactyls aren't (chalicotheres).   
   >>> I'd say that convergence in hoofiness is considerably more   
   >>> parsimonious given the data, even forgetting about Dollo's Law.   
   >>>   
   >>   
   >> I believe that notoungulates and litopterns are hoofed stem-   
   >> perissodactyls. If chalicotheres are primitively clawed, this requires   
   >> convergence in Hippomorpha, Ceratomorpha, Notoungulata/Litopterna, and   
   >> possibly other groups.   
   >>   
   > It's also possible that chalicothere claws, which actually are a bit   
   > weird-looking, are a real example of a reversal. I'm also wondering what   
   > Ambulocetus, etc., digits look like.   
   >   
      
   The article that I read claimed that Ambulocetus had the bones at the   
   tip of it's toes are slightly flattened on top indicating that it had   
   hooves, but the bones did not show the widening that would indicate some   
   type of substantial hoof.  I can't recall exactly, but they might have   
   called them some type of fingernail like hoof.   
      
   Ron Okimoto   
      
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