Chalice classification questions

[Mscott203]

Could someone explain the dfference between some of these classifications I have run across. All seem similiar to me.
Chalice, oxypora, pectinia, mycedium, Acanthastrea echinata.

This was sold to me as a "rugosa", hmm, If Wikipedia is correct I must really have something - Wikipedia - "an extinct order of coral that were abundant in Middle Ordovician to Late Permian seas".
I second guessed the lfs owner and believe it to be a chalice of some sort but I really cant tell the difference between the above named classifications.

 

[Hormigaquatica]

"Chalice" is just a common/trade name that covers a variety of corals, even different families (most are Pectiniidae, theres at least one from Faviidae). Echinophyllia, Echinopora, Oxypora, and Mycedium are the ones it most commonly referred to. You mentioned Pectina and Acanthastrea echinata- if you check a few ID resources, or familiarize yourself a bit more with those particular corals, they are very easy to distinguish from the other genera you mentioned- just need to familiarize yourself with them a bit more is all.

Of the other 4 genera Ive listed above, Mycedium is usually the easiest one to ID, though can still be a challenge. It generally has a fairly smooth appearance, with very distinct 'eyes' that raise above the surface, and often all point in the same direction. The other 3 general have a rougher appearance. Aside from that, its difficult to make generalized comparisons between the groups- its really a matter of getting a good ID source, and doing comparisons. Veron's "Corals of the World" is a great guide and includes a fair number of skeletal images, which are the most accurate way of IDing a coral. If you cant get a hold of that book set, there is an online database that he has set up that is still pretty good. Check it out HERE

For what its worth, 'rugosa' is also the species name for a couple of different corals (Pachyseris rugosa and Porites rugosa come to mind). Yours is not one of those. My best guess on your particular piece is that its a species of Echinophyllia.

 

[Mscott203]

thanks very much Hormigaquatica

that was all just the info I was seeking and helps a ton.