NEW CHINIQUODONTID & SAUROPOD REVIEW

[darren.naish@port.ac.uk]

The current issue of _Palaeontology_ has two other papers 
of interest not yet mentioned here. They are...

Abdala, F. and Giannini, N. P. 2002. Chiniquodontid 
cynodonts: systematic and morphometric considerations. 
_Palaeontology_ 45, 1151-1170.

Chiniquodontids are diagnosed by the form of the base of 
the zygomatic process and expanded pterygoid flanges. An 
analysis of all taxa shows that all of them form a single 
growth series, though _Chiniquodon sanjuanensis_ (new 
combination for _Probelosodon sanjuanensis_ Martinez & 
Forster 1996) can be differentiated from _C. theotonicus_ 
on the basis of dentition and the shape of zygomatic 
process. In contrast to recent reviews by Hopson (1991) and 
Battail (1991), _Cromptodon_, _Probainognathus_, 
_Thrinaxodon_, _Aleodon_ and _Cistecynodon_ are 
excluded from the chiniquodontids.

Barrett, P. M., Hasegawa, Y., Manabe, M., Isaji, S. & 
Matsuoka, H. 2002. Sauropod dinosaurs from the Lower 
Cretaceous of eastern Asia: taxonomic and biogeographic 
implications. _Palaeontology_ 45, 1197-1217.

Isolated teeth from the Kuwjima Fm (Berriasian-
Hauterivian, Japan) are referable to the Titanosauriformes 
(but not to titanosaurs). The biogeographical implications of 
this are discussed - and it makes a difference whether 
euhelopodids are recognised as a clade or not. Other east 
Asian sauropod records are examined and here are the 
summarised results. 

(1) No nemegtosaurids in Japan - the tooth referred to this 
group by Tanimoto & Mizutani (1999) is from a 
_Pleurocoelus_-type titanosauriform and another reported 
by Barrett & Manabe (2000) is from a pterosaur. 

(2) _Asiatosaurus mongoliensis_ Osborn 1924 is a nomen 
dubium and should be regarded as Eusauropoda indet. 
(contra Calvo 1996). _A. kwangshiensis_ Hou et al. 1975 is 
also a nomen dubium. 

(3)  _Chiayusaurus lacustris_ Bohlin 1953 is also a nomen 
dubium and an indeterminate eusauropod. _C. asianensis_ 
Lee et al. 1997 is a nomen dubium but a probable 
titanosauriform.

(4) _Euhelopus_ Romer 1956 is clearly valid and well 
supported by many autapomorphies. Barrett et al. support 
monophyly of euhelopodids and argue that Upchurch's 
analyses have a higher statistical rigour than Wilson and 
Sereno. Their paper was obviously submitted prior to 
Wilson's new ZJLS paper and when I spoke about the 
problem of euhelopodid monophyly with Jeff at SVPCA he 
said that he and Paul Upchurch no longer disagreed on this 
issue. Seeing as Jeff's ZJLS paper still supports non-
monophyly of Euhelopodidae I take it Paul's latest analyses 
are finding the same result. Mickey did show the latest 
Upchurch and Barrett sauropod cladogram in one of his 
emails so this will be easy to check.

(5) _Mongolosaurus haplodon_ Gilmore 1933 is also a 
nomen dubium, Neosauropoda indet, and presents an array 
of possible diplodocoid and titanosaur features (they do not 
mention suggestions that it might be a nemegtosaurid, and 
no support for George's idea that it might be an aberrant 
therizinosauroid:)). Further study needed. 
        Incidentally Barrett et al. refer to titanosaurs as 
Titanosauroidea. I'm not too keen on this term as Upchurch 
originally introduced it for _Opisthocoelicaudia_ plus other 
titanosaurs and, seeing as  _Opisthocoelicaudia_ is now 
nested well within conventional 'titanosaurids', I would 
argue that the term is not useful. Then again, Upchurch did 
say he introduced it to bring (Linnean-style) stability to 
sauropod taxonomy.

(6) _Phuwiangosaurus_ is deemed contentious and Barrett 
et al. are not sure of its proposed affinity with 
nemegtosaurids. Though they cite Curry Rogers and Forster 
(2001) they seem unconvinced of the titanosaurian status of 
nemegtosaurids and opt for a basal titanosaur position. This 
was written before recent data by Buffetaut was presented 
though.

(7) _Ultrsaurus tabriensis_ Kim 1983 is a nomen dubium 
and Sauropoda indet.

Well, there's more, but I'll be here all day if I continue.

-- 
Darren Naish
School of Earth & Environmental Sciences
University of Portsmouth UK, PO1 3QL

email: darren.naish@port.ac.uk
tel: 023 92846045