[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: Graphic request - plain text this time.

One difficulty is that the relationships of ichthyosaurs and 
sauropterygians--to each other and to other clades, extinct and extant--is 
among the most contentious in vertebrate systematics. It is on par with--and 
indeed sometimes related to--the eternal quest to find the position of turtles. 
(BTW, new information on that forthcoming: let's just say that turtles as 
crown-saurians is not yet finally solidified!)

One of the most extensive recent studies with the broadest sampling of relevant 
taxa was the Cartorhynchus paper 
(http://www.nature.com/nature/journal/v517/n7535/full/nature13866.html). In 
this paper, using the tree using all the characters, there is a clade of 
thallatosaurs +((ichthyosaurs + hupehsuchians) + (saurophargids + 
sauropterygians)), collectively the sister taxon to the rest of 

Although the Pappochelys paper did not include as diverse a sampling of taxa as 
did this one, it did find Sauopterygia as the sister group to Pappochelys + 
Testudinata, but as the sister taxon to other Lepidosauromorpha rather than as 
the basalmost archosauromorph clade. (No ichthyosaurs in that analysis, 

One possibility is to show a graph with a four-way split at the base of Sauria: 
Archosauromorpha (show some birds, other dinosaurs, pterosaurs, crocs), 
Testudinata (show sea turtles, and some turtles), Euryapsida (show 
ichthyosaurs, placodonts, plesiosaurs), and Lepidosauromorpha (show snakes, 
mosasaurs, other lizards).

I don't know if such a graphic yet exists, but perhaps someone reading this 
could whip one up.

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu         Phone: 301-405-4084
Senior Lecturer, Vertebrate Paleontology
Office: Geology 4106, 8000 Regents Dr., College Park MD 20742
Dept. of Geology, University of Maryland
Phone: 301-405-6965
Fax: 301-314-9661              

Faculty Director, Science & Global Change Program, College Park Scholars
Office: Centreville 1216, 4243 Valley Dr., College Park MD 20742
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        8000 Regents Drive
                        University of Maryland
                        College Park, MD 20742-4211 USA 

> -----Original Message-----
> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf Of 
> Ralph Chapman
> Sent: Friday, October 23, 2015 1:59 PM
> To: Dinosaur List
> Subject: Graphic request - plain text this time.
> Sorry, forgot to click the PT box....
> Hey guys and ladies:
>      Up here in Los Alamos we have an nature center - the Pajarito 
> Environmental Education Center or PEEC - that has a planetarium
> where the also show films. They are bringing in the Geographic film "sea 
> Monsters" (I know, I don't like that name either) and, for the
> opening, they have asked me to introduce the film and the cast of characters. 
> I am looking for some sweet intro graphics on the
> phylogenetic position of Mesozoic marine reptiles but don't like any I have 
> found so far. Can you guys recommend a nice one or two
> that will look nice when I throw it on the dome (with attribution, of 
> course). The rest of the individual taxa are not a problem, but the
> nice and concise position on the tree graphic is what I'm still looking for.
> If you know of some good ones, you can send to me directly - 
> ralphchapman@earthlink.net - and if the list wants, I'll summarize and
> put one email for the list together after a while.
> FYI, it's an interesting film that also highlights some paleontologists, 
> including the Sternbergs and some recent people, although they
> seem to only ID the Sternbergs by name which left me saying but, but, but 
> that's ....
> Anyway, I appreciate any effort you guys put in to help here.
> Finally a nice day here after a lot of rain in the newly minted Seattle of 
> the Southwest. An incredibly rainy year for us.
> Have a great weekend, Ralph
> Ralph E. ChapmanPaleontologist & TechnologistLos Alamos Business incubation 
> (LABi)102 El Morro StreetLos Alamos, New Mexico
> 87544(505) 500-5266ralphchapman@earthlink.net
> Ralph E. ChapmanPaleontologist & TechnologistLos Alamos Business incubation 
> (LABi)102 El Morro StreetLos Alamos, New Mexico
> 87544(505) 500-5266ralphchapman@earthlink.net