Dear Dave,
Yes, they both look like Synallactids, no idea about the upper individual,
I dont think its a Mesothuria, but... no other clue.
The bootom one seems to me like a Synallactes.
Great beasts! but also terrible that we dont have specimens...

Francisco

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> Dear Colleagues, please see attached.  Dave P.
> ________________________________
> From: Pawson, David
> Sent: Monday, June 10, 2013 6:03 PM
> To: [log in to unmask]; [log in to unmask]; [log in to unmask]
> Subject: Two unknown (?) deep-sea holothurians - any ideas please?
>
>
> Dear Esteemed Colleagues,
>
> Attached is an image of two holothurians from the northern Gulf of Mexico.
>  We do not have specimens of these, unfortunately.
>
>    The upper individual is probably about 20 cm long, and is lying on its
> presumed right side.  It has a thin veneer of sediment on its upper
> surface, no obvious pygal furrow, some transverse dorsal wrinkles, and
> ca. 15 large papillae in each ventrolateral radius, which show up in
> other images as more rounded protuberances... Mesothuria sp??
>
>    The lower individual is perhaps also about 20 cm long, with few
> scattered fine dorsal papillae, and about a million ventrolateral feet.
>
>     I presume they're both synallactids...?  Any suggestions would be much
> appreciated, and of course acklnowledged!
>
>   Yours in eternal puzzlement,  and best wishes!  Dave Pawson
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>
>
> David L. Pawson
> Senior Research Scientist,
> Dept. of Invertebrate Zoology,
> Mail Stop MRC163,
> Smithsonian Institution,
> Washington DC 20013-7012.
> Phone; 202-633-1757
>


Dr. Francisco A. Solís-Marín
Jefe de la Unidad Académica Ecología y Biodiversidad Acuática.
Colección Nacional de Equinodermos
"Dra. Ma. E. Caso Muñoz"
Instituto de Ciencias del Mar y Limnología
Universidad Nacional Autónoma de México
Circuito Universitario s/n
Deleg. Coyoacán
Mexico, D,F.,
CP. 04510
Tel. (52) 56-22-58-43