Mystery ecphora

[Frank Eaton]

I love the ecphora for their improvisations but...

I’ve searched the photos from Ward and Petuch for anything similar to this ecphora from the James River in Virginia. It’s a globose shell with six distinct costae. 
 

specimen is three inches long.

[MikeR]

Hi Frank

 

I find that the best way of identifying Ecphora is to know the geological unit and collect it in-situ, especially on the James River where both Upper (Piacenzian) and Lower (Zanclean)Yorktown Formation is exposed along with Upper Miocene Eastover.  I religiously follow Ward as I have spent days at a stretch with him in the field trying to learn from the master.  As a biostratigrapher, Buck's version of Ecphora is much different from Petuch's where every slight variation is a new species.  That said, I think the additional ribs are a variation or mutation of a gerontic specimen, however if you contact Petuch I am sure he would name new species after you if you gave it to him.  Seeing an aperture view of your shell would help as well, but I am thinking Ecphora kochi from the Cobham Bay Member of the Eastover Formation. 

 

Mike

[Frank Eaton]

Thanks, Mike- we're in luck! I did capture this in situ from a Cobham Bay deposit above a calcified layer of dinner plate sized chesapecten, a few small placopecten, and big colonies of blonde barnacles. I found two exquisitely intact Ecphora kochi that were protected by barnacles here, so kochi was where I started with this one as well. 

 

I like your theory that this is an old animal or a pathologic specimen (I also like the idea of sending it to Petuch to secure my place in the pantheon). My favorite thing about this species is how impressionistic they are, like each snail puts his own spin on the theme of Ecphora. Or maybe like a lot of artists I know, they drink too much. 

 

Jealous of your time with Ward. Here's a look at the umbilicus. I'll try to upload a few more angles when the site resets my upload limit.

 

Frank

[Frank Eaton]

Here's Ed Petuch's reaction:

 

it's an E. whiteoakensis. they sometimes come with extra ribs like that----E. asheri from Zone 22 St. Mary's Formation also has these multiple ribs, again some with as many as 8 or 10 ribs----but other species, like gardnerae and meganae never have extra ribs---weird---so, you found a very special whiteoakensis and I hope that you find more like that----so, I hope that this helps!

 

 

[MikeR]

I can go with Ecphora gardnerae whiteoakensis, however it has a very limited range and therefore you were in the Claremont Manor Member of the Eastover Formation.  The picture below on the left is from Ward's Locality 7 (USGS 26066) and when the individual layers are weathered it is very difficult to tell which formation is which.  A fresh fall further on down the bluff shows that the Claremont Manor Member is actually quite dark.  The last picture is E.g. whiteoakensis from the Claremont.

 

Mike