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JamieLynn

How to decipher scientific notation?

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JamieLynn

In my attempt to self educate myself, I am tring to find as much information on the Texas Cretaceous fossils I find. I am a bit confused about the scientific notation of genus species.  For example, in much of the literature, there will be a name in parenthesis : like Pecten (Neithia) texanus or  Trochus (Tectus) texana.  (examples from the Studies of Some Comanchean Pelecypod paper). And in the Field Guide to Fossils of Texas, Mesalia (Turritella) seriatim-granulata  and Gyrodes (Sohlella) spillmani.  What does that mean? Is Pecten the proper name or Neithia? Is it Mesalia or Turritalla? Or is it both?

 

Or if there is a question mark after the genus - like Cerithium? barionnenne    or  Pseudomelania ? pupoides  (Both examples from the Studies of Some Comanchean Pelecypod paper). Are they just not sure if that is the proper Genus and leaving it open to interpretation and further study? 

 

Any help is appreciated! 

 

 

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Phevo

It kinda depends

 

I think the (Neithia),  (Turritella) and (Sohlella) is a reference to it's previous assigned genus.

 

The question mark means the author is uncertain about the genus, usually I see it written as cf. (compare to), but I think it depends on how old the litterature you are reading is

 

In Denmark we have some sea urchins that have swapped genus a couple times back and forth so it can be a mess...

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DPS Ammonite

Check out two websites for sorting out taxonomic names: Fossilworks and WoRMS. Note that they do not always agree. I do consider a species name accurate using either of the sites even if they dissagree.

 

In regards to Mesalia and Turritella, it appears that some consider Mesalia to be a subgenus of Turritella while some consider Mesalia to be a genus. Thus Mesalia is in parentheses. Link. WoRMS does not accept Turritella (Mesalia). Link. Fossilworks lists a different Turritella (Mesalinia) species as an alternative spelling of Mesalinia. Link. Fossilworks considers “Mesalia (Turritella) seriatim-granulatato” to be a Turritella without mentioning Mesalia. Link.

 

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JamieLynn

wow thank you for the "clarification"!  It is all now clear as mud! hahahhah Seriously, thank you for the explanation. 

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doushantuo

I'd advocate (getting a wee bit technical here, Jamie Lynn) using the Linnean binomial, name of the author of the species, and date of authorship.

This allows for more easy retrieval of the original reference.

e.g.:

there were(used to be)

Rana microtympanum van Kampen 1907 (a frog,BTW)

and 

Rana microtympanum Boulenger 1919.

Which raises the question: is the same species being described here?

(The first species is now Limnonectes, BTW)

Boulenger was pretty prolific, so adding the date helps in finding the data (original description) quicker. 

edit (8:50 local time) spelling correction

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FranzBernhard
8 hours ago, FossilDAWG said:

The previous post serves to highlight that there is no hard and fast rule about when to call something a genus or a subgenus.  Rather, the community of working taxonomists whose expertise includes the species in question will hopefully come to a consensus, though this may not happen or it may take a while for some agreement to emerge.  In this case, Turritella is the older genus name, having been created by Lamarck in 1799, and many many species have been described as members of the genus.  Subsequently Gray decided that there seemed to be some clusters of species within Turritella that were more similar to one another than they were to other species or clusters of species in the genus.  One of these clusters he named as a subgenus, Mesalia, in 1847.  This subgenus is written Turritella (Mesalia).  Of necessity, this also led to the creation of a subgenus, Turritella (Turritella), to contain those species closest to Lamarck's original concept of Turritella.  Later other researchers decided that the difference between Turritella (Turritella) and Turritella (Mesalia) was large enough to justify raising Mesalia to the rank of genus.  Other researchers disagree, and continue to regard Mesalia as a subgenus. 

 

Of course "genus" and "subgenus" are not strictly defined anywhere, they are categories of convenience that were invented by Lamarck to facilitate classifying organisms.  Think of comparing branches on a tree to a phylogenetic tree of species; twigs at the end are analogous to species, the next level of branches are analogous to genera, and so on for families, orders, classes, and phyla.  However there is a lot of variation between branches, some divide after only a short distance while others grow a much longer distance out from the trunk before branching.  There isn't a well-defined measure that allows us to say this branch is exactly the same as that branch.  We can agree on the big picture and the overall shape of the tree, but there will be disagreement about how to classify the branches, especially the ones between the trunk (kingdom) and twigs (species).

 

In the end it doesn't matter much to most of us if we call things Turritella (Mesalia) or Mesalia, as long as we understand it's six of one or half a dozen of the other. 

 

Regarding the Fossilworks site, my understanding is that they pay more attention to vertebrates than invertebrates, so their names for invertebrates may be pulled directly from 100 year old publications without allowing for any revisions to the taxonomy. 

 

Don

Thanks so much for this insightfull elaboration!
Franz Bernhard

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doushantuo

Weylia,Janira,Pecten s.s.have all been "confounded" at some time or another

The general morphology of Neithea has "homeomorphs",like the Bathonian Pseudovola depereti.

The 1824 description by Drouet specifically mentions the isodont hinge teeth,BTW as a distinguishing character.

 

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Uncle Siphuncle

It may serve well to bring the terms junior synonym and senior synonym into this discussion of genera.

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FossilNerd

Welcome to the wonderful world of fossils! 
 

Finding the things can be challenging enough. Figuring out what to call them is a whole other beast entirely! It’s a life long learning process that can change in an instant. At least it keeps life interesting! ;)
 

 

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connorp
On 11/12/2019 at 12:10 PM, JamieLynn said:

Or if there is a question mark after the genus - like Cerithium? barionnenne    or  Pseudomelania ? pupoides  (Both examples from the Studies of Some Comanchean Pelecypod paper). Are they just not sure if that is the proper Genus and leaving it open to interpretation and further study?

 

On 11/12/2019 at 1:29 PM, Phevo said:

The question mark means the author is uncertain about the genus, usually I see it written as cf. (compare to), but I think it depends on how old the litterature you are reading is

At least from what I've read, uncertain genera are often denoted using questions marks, so Cerithium? barionnenne is a species uncertainly assigned to the genus Cerithium. Often this use refers to groups of known fossils rather than individual specimens. For example, Branchiocaris is a genus of arthropod originally described from the Burgess Shale. However, identical carpaces have been found from the Chengjiang biota in China, but none of the soft body parts have been preserved there as they are in Burgess Shale specimens. So carpaces from Chengjiang localities are listed as Branchiocaris? yunnanensis, since these specimens most likely all belong to the same species but there is uncertainty in assigning them to the genus Branchiocaris from the Burgess Shale.

 

On the other hand, cf. can be used for both groups of fossils and individual specimens. This term is often used when specimens are not well preserved or complete enough for a species level identification. For example, I recently found a partial shark tooth of the genus Petalodus. The only such species known from this locality is Petalodus ohioensis, and the crown fragment I have looks identical to crowns of complete specimens of Petalodus ohioensis from this locality. However, as I don't have the whole tooth, I cannot assign it to a species with certainty, so I would label it Petalodus cf. ohioensis.

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JohnJ

A minor note:  cf. or sp. are not italicized.  

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DPS Ammonite
1 hour ago, JohnJ said:

A minor note:  cf. or sp. are not italicized.  

Mea culpa. Please do not use as an example of correct form for italicizing and ignore the formatting glitch in the collections. It will automatically italicize cf. and sp. when entered in the species field. Everything is also italicized in the genus field too including punctuation such as a question mark. Only the specific and generic names should be italicized. A partial solution would be to turn off the auto italicize feature and then manually italicizing the proper parts.

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