[Taxacom] Primates (was: burn out)
John Grehan
jgrehan at sciencebuff.org
Thu Apr 23 07:08:32 CDT 2009
The postion of tarsius and hence the monophyly of Haplorhini remains problematic and even various molecular studies have rendered conflicting results. The rhinarium may be the only verified morpholgoical apomorphy shared by tarsiers and anthropoids. Although tarsiers appear to have a reduced snout, this is an artifact of their large eyes extending forward over the snout. There are a lot of features proposed as apomorphies for tarsiers and anthropoids but most, on my current examination, do not appear to be sustainable.
Evidence for monophyly of tarsiers and other prosimians is equally challenging. A solid apomorphy for tarsiers and strepsirrhines is the presence of a nail on the second foot. Two other features may be an intrabuller tympanic ring, and lateral shelf at the ede of the incisors (effectively the remnant of the prosimian toothcomb - although the lateral structure is also found Tapaia). There are also some dental features that may suggest a most close relationship between tarsiers and lorisiforms.
As poined out by Michael Heads, reconstructions supporting a sistergroup relationship between Plesiadapiformes and living primate taxa would suggest that the ancestor was no more like one than the other. More likely it would be a combination. Various authors have also argued about the relative positon of some other living mammal groups with the possiblity that they are closer than plesiadapiforms.
One of the challenges with fossil primate systematics is the lack of clarity over characters. Many fossils are represented by a few teeth at best, and for many the descriptions are a convloluted morass of differences and simialrities. Recently the claim for the oldest Asian anthropoid in India was based on three teeth without any definitive identification of characters that made these teeth primate let alone anthropoids. It's a mess out there.
As for the paraphyletic 'Pongidae' it has no phylogenetic existence. If one wants to give a formal taxonomic name to a collectino of primitive retentions then ok for those who want to, but its otherwise uninforamtive.
John Grehan
> -----Original Message-----
> From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-
> bounces at mailman.nhm.ku.edu] On Behalf Of Kenneth Kinman
> Sent: Wednesday, April 22, 2009 11:01 PM
> To: taxacom at mailman.nhm.ku.edu
> Subject: [Taxacom] Primates (was: burn out)
>
> Hi All,
> Actually, we have a reasonably good idea what our primate ancestors
> were like at various stages of our evolutionary line. The primate
> classification which I posted here on taxacom in December 2004 is given
> below for reference. I haven't had time to update it, but it gives a
> good idea of the evolutionary stages our ancestors went through.
> Before we entered the "monkey" stages, our ancestors went through
> "tarsiiform" stages at the beginning of Suborder Haplorhini.
> Tarsiiforms (a paraphyletic assemblage) are three successive clades
> (Omomyidae/Microchoeridae; Tarsiidae; Afrotarsiidae), giving us an idea
> what our "tarsioid" ancestors were like. And before that our ancestors
> went through several "plesiadapiform" stages (Suborder Proprimates).
> Plesiadapoids (Plesiadapidae and Carpolestidae) are paraphyletic, as are
> Microsyopoids (Palaechthonidae, Picrodontidae, and Microsyopidae).
> The point is that there are lots of potential paraphyletic
> assemblages in this classification, but I only formally recognize three
> of the most important ones (Proprimates%, Pongidae%, Australopithecus%).
> The alphanumeric coding shows the relationships without cluttering up
> the classification with a lot of suboptimal paraphyletic taxa (or
> suboptimal clade names either). And just because a lot of these familes
> are "dead" (extinct) doesn't make them irrelevant. There is a lot of
> good information in the "dead" Suborder Proprimates, whether you want to
> look at the taxa as just successive clades only, or group some of them
> as paraphyletic superfamilies.
> As a consensus classification, it is meant to serve the needs of
> both strict cladists and eclecticists. And it obviously doesn't require
> a lot of formal paraphyletic taxa. We should be very selective what
> formal paraphyletic taxa we recognize. I just see no need to insist
> that Family Pongidae (great apes) must include humans and
> australopithecines. Just make sure that the {{Hominidae}} exgroup
> marker is in there to show how the 2 families are related cladistically.
> Finally, we clearly have plesiadapiform and tarsiiform ancestors, but I
> see no reason to say we ARE plesiadapiforms (or we ARE tarsiiforms).
> Better to say that our ancestors WERE plesiadapiforms and tarsiiforms.
>
>
> ORDER PRIMATES (sensu lato)
> 1 Proprimates% (plesiadapiforms)
> 1 Purgatoriidae
> 2 Plesion Pandemonium
> 3 Micromomyidae
> 4 Paromomyidae
> ? Picromomyidae
> 5 Palaechthonidae
> 6 Picrodontidae
> 7 Microsyopidae
> 8 Plesiadapidae
> 9 Carpolestidae
> 10 {{Euprimates}} (= Strepsirhini + Haplorhini)
>
> _1_ Strepsirhini
> 1 Notharctidae
> Sivaladapidae
> Adapidae
> 2 Plesiopithecidae
> 3 Galagonidae
> B Loridae
> 4 Daubentoniidae
> 5 Cheirogaleidae
> 6 Megaladapidae
> 7 Indriidae (sensu lato)
> 8 Lemuridae
>
> 2 Haplorhini (tarsiforms & anthropoids)
> 1 Omomyidae
> B Microchoeridae
> 2 Tarsiidae
> 3 Afrotarsiidae
> 4 Eosimiidae
> 5 Amphipithecidae
> B Parapithecidae
> C Atelidae
> D Cebidae
> 6 Cercopithecidae
> 7 Propliopithecidae
> 8 Pliopithecidae
> 9 Proconsulidae
> ? Oreopithecidae
> 10 Hylobatidae
> 11 Pongidae% (sensu lato)
> 1 Dryopithecus
> ? Ouranopithecus
> 2 Lufengpithecus
> B Sivapithecus
> C Khoratpithecus
> D Pongo
> 3 Gorilla
> ? Samburupithecus
> 4 Pan
> 5 Sahelanthropus
> 6 Orrorin
> B Ardipithecus
> 7 {{Hominidae}}
>
> _a_ Hominidae
> 1 Australopithecus% (sensu lato)
> _a_ Homo
>
> *********************************
> Richard wrote:
> "Monkeys"? I don't think it is yet clear what we are descended from in
> the hominiod line (unless it is a node). Maybe we are all descended from
> nodes. Of course if we could identify a paraphyletic group somewhere in
> the hominoid line, then we might have an idea of what at least one of
> the ancestors of humans might look like : )
>
>
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