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Adam Smith wrote....
> Eusauropterygia was proposed by Storrs (1993)for a
> more exclusive clade within Sauropterygia. However,
> subsequent revision of sauropterygian
> interrelationships (Rieppel, 1998)revealed it to be
> polyphyletic and therefore redundant. I wasn't aware
> the term was still in formal use. Am I missing a key
Check any of Rieppel's papers from the last 4-5 years.
Eusauropterygia (proposed by Tscahnz 1989, not Storrs
1993) is used as the nothosauroid + pistosauroid clade.
Pachypleurosaurs, previously argued by Rieppel (1998) as
sister group to Nothosauroidea, are presently regarded as
the sister-group to the Eusauropterygia.
Pachypleurosauria + Eusauropterygia = Eosauropterygia.
Eosauropterygia + Placodontia = Sauropterygia, thus
placodonts are the most basal sauropterygians known at
It's not entirely helpful that eosauropterygians and
eusauropterygians have names that differ by only one letter.
Rieppel, O. 1998. _Corosaurus alcovensis_ Case, and the
phylogenetic interrelationships of Triassic stem-group
Sauropterygia. _Zoo. J. Linn. Soc._ 124, 1-41.
- . 1999. Phylogeny and paleobiogeography of Triassic
Sauropterygia: problems resolved and unresolved.
_Paleogeography, Paleoclimatology, Paleoecology_ 153, 1-
- . 2000. _Paraplacodus_ and the phylogeny of Placodontia
(Reptilia: Sauropterygia). Zool. J. Linn. Soc._ 130, 635-
- . 2000. Sauropterygia 1: Placodontia, Pachypleurosauria,
Nothosauroidea, Pistosauroidea. In Wellnhofer, P. (ed)
_Encyclopedia of Paleoherpetology, Vol. 12A_. Pfeil,
Munich, pp. 134.
Tschanz, K. 1989. _Lariosaurus buzii_ n. so. from the
Middle Jurassic of Monte San Giorgio (Switzerland), with
comments on the classification of nothosaurs.
_Palaeontographica A_ 298, 153-179.
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