Re: "Hypuronector limnaios"

[Silvio Renesto <renesto@mailserver.unimi.it>]

At 22.33 24/10/01 -0600, you wrote:
>On Wed, 24 Oct 2001, Daniel Bensen wrote:
>> Hey, guys
>> Does the name ""Hypuronector limnaios" mean anything to you all?  Is it
>> new or fradulent, or haven't I been listening to the list well enough?
>
> http://members.gotnet.net/maier/Dinosaurs/Megalancosauruspreonensis.html
>
> Megalancosaurus preonensis is a megalancosaurid, a bizzare reptile of
> uncertain affinities.  While one species of megalancosaurid (Hypuronector
> limnaios)  has adapted to an aquatic exsistance, most megalancosaurids
> are arboreal. 

To put my two cents:
1)  the authors put Hypuronector (= Deep Tailed Swimmer) limnaios (= from
the lake)in the Drepanosauridae (correctly; it is feasible that
drepanosauridae and Meglancosauridae are synonymous  and Drepanosauridae
has priority over Megalancosauridae)

2) That adaptation toward aquatic life is a highly respectable
interpretation of the author, to which I respectfully disagree. In my not
so respectable opinion, nothing points to life in water in Hypuronector. Do
not stop looking at the odd tail, but give a look at the skeleton AS A
WHOLE.  When Berman and Reisz described the drepanosaurid Dolabrosaurus,
they gave it the specific name "aquatilis", considering it an aquatic form.
 Indeed available remains of Dolabrosaurus share all the arboreal
adaptations of Drepanosaurus, Megalancosaurus and "Vallesaurus (nomen
nudum)" .  The problem is that when someone finds a deep tail in an animal
collected in an an aquatic environment is strongly tempted to see a
sculling organ. This is reasonable, but in the case of all known
drepanosaurids,(IMHO Hypuronector included), a more deep analysis reveals
that the tail is laterally stiff and dorsoventrally mobile at its base. And
these lightly built animals most probably have been washed out (or in?)
from their true environment. The tail served for other functions. I do not
want to repeat myself or become too long here, so if anyone there is
interested in further comments on how and why, please mail me either
privately or on the list depending if the thread is of interest or not.

All the best,

                                        Silvio Renesto

-

"Who looks for Knowledge increases himself every day
who looks for Wisdom loses himself every day"   
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Dr. Silvio Renesto
Dipartimento di Scienze della Terra
Università degli Studi di Milano
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I 20133 Milano
Italy

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