“Eupleura pterina” or Pterorytis dryas?

In 1947, Julia Gardner named two species of ocenebrines from the Alum Bluff Group. The first was “Pteropurpura dryas” from the Oak Grove Sand, now referred to Pterorytis (Microrhytis). The second was “Eupleura pterina” from the Shoal River Formation, which was named on the basis of only two specimens, which Gardner admitted might not be fully mature. Both species are shown in the image below.

 

Last Thoughts on Pterorytis…

As alluded to in my previous posts on the genus Pterorytis, Vermeij and Vokes (1997) have synonymized several species listed in Petuch’s (1994) Atlas of Florida Fossil Shells with P. umbrifer and P. fluviana. However, everyone must make their own decision as to which scientific opinion they feel is correct, or whether the truth lies somewhere in between.

 

More on Those Pesky Pterorytis…

While I am fully immersed in “Pterorytis mode,” I figured I may as well do another post on the genus (perhaps even a few more!)

 

Toothless Pterorytis – They’re Not All P. roxaneae!

In an earlier post, I alluded to the fact that it is very difficult to properly identify many fossil species from southern Florida today. Much of the extant literature provides only brief, general descriptions with minimal figures for comparison. Thus, I have seen many collectors name the specimens in their collection based solely on where they came from (ignoring morphological characteristics of the shells altogether), or conversely, name their specimens based only on superficial similarity to a published photo, without adequate regard to geology. I say this not to condemn, because I recognize as much as anyone how difficult it is to make sense of much of the literature that is readily available to amateur collectors. But it does complicate things for those of us lacking a PhD in the field (if you recall, my PhD is in business administration / information systems).