About Trilobites...metacanthina Or Hollardops? Andalusiana Or Cambropallas?

[-Andy-]

I 've got questions about these trilobite species.

Basically, when I search for Cambropallas, I also get search results of Andalusiana. Sometimes the results even show Cambropallas (Andalusiana).

The same occurs for Metacanthina and Hollardops, where results of Hollardops (Metacanthina) occurs.

Are Metacanthina and Hollardops the same family of trilobites? Which is the scientific name?

Are Andalusiana and Cambropallas the same family too? Which is the scientific name?

Thanks!

[piranha]

Good questions Andy:

 

Yes, these are each distinctive genera. I can point out a few of the differences but it is important to keep in mind that ebay (90%) and many commercial sellers of trilobites are often incorrect when describing trilobites, especially the Moroccan material. Some are certainly very lazy but for the most part just lagging behind the current taxonomy. The words 'Rare' and 'Undescribed' are generally unwarranted terms but that is another discussion. Part of the larger problem is / was (continues): as the internet first arrived it coincided with an explosion of trilobites coming out of Morocco. Early on and out of convenience many of these trilobites were simply given temporary placeholders, typically named as analogous European genera. As the specialists march forward the revisions can seem quite confusing and even many outstanding papers are rendered partially obsolete (taxonomically) a short time later as new discoveries warrant the tireless business of reshuffling.

 

Hollardops and Metacanthina (Order Phacopida - Family Asteropyginae) have been playing a fun game of musical chairs. Hollardops was formally Asteropyge. Metacanthina was previously referred to as Asteropyge or Kayserops and along the way, Philipsmithiana never quite made it as a new name before Hollardops officially occupied the name for that genus. Attached are figures of Hollardops and a link to a gallery of Metacanthina for comparison. Suffice it to say there are a myriad of species and these two particular examples represent only the most common elements of the group as a whole.

 

Andalusiana and Cambropallas (Order Redlichiida - Family Holmiidae) have also been inadvertently mistaken for one another but the differences are fairly easy to discern once you know what to look for. I've attached a few figures for these as well as a link to an excellent articulated example of Andalusiana for comparison. If you or anyone would like copies of a few of these professional papers please send me a PM with email address and will be happy to share them. The papers on the asteropyginids should be evaluated with the aforementioned caveat; that many of the Moroccan genera / species have since been revised in recent years and will continue to evolve for many years to come. That's the fun part.

Hope this helps to clarify these trilobites for you

 

Hollardops

Metacanthina LINK

Andalusiana

Andalusiana LINK

Cambropallas

[-Andy-]

Thanks so much for the links Piranha.

I am no expert however, and any suggestions to their species would just be guesswork on my part. I 've posted a thread on the ID forum to ask for help.

http://www.thefossilforum.com/index.php/topic/28379-morrocan-ammonite-and-trilobites/page__gopid__313284#entry313284