Cadulus or Polyschides?

[sixgill pete]

 

This Scaphopod is from the Pliocene Yorktown Formation, Rushmere Member. Found in some matrix from the inside of a large Ecphora from the Tar River in Edgecombe County, North Carolina. One resource I have at home (NCFC volume 2, Fossil Molluscs) calls this Polyschides thallus while every online resource I can find online calls it Cadulus thallus. I cannot find any resource showing a change in Genus from Cadulus to Polyschides. Does anyone have a resource showing this? Which one is correct?

[doushantuo]

Cadulus,based on morphology,but don't quote me on that

Will look into this

am looking at this right now

Catalog of species-group names of Recent and fossil Scaphopoda (Mollusca)
Gerhard STEINER Alan R. KABAT

ZOOSYSTEMA • 2004 • 26 (4) 

1,20 Mb

[DPS Ammonite]

Here is some info that mentions that Cadulus and Polyschides are related: 

http://www.marinespecies.org/aphia.php?p=taxdetails&id=196387

 

[doushantuo]

this links to Pilsbry and Sharp

The type species of Polyschides Pilsbry & Sharp is apparently Cadulus tetraschistus Watson 1879(by original designation)

the name change might be in:

Henderson, J. B. 1920. A monograph of the east American scaphopod mollusks. U. S. Nat. Mus. Bull. Ill: 177 p., 20 pis.??
 

 

[sixgill pete]

8 hours ago, DPS Ammonite said:

Here is some info that mentions that Cadulus and Polyschides are related: 

http://www.marinespecies.org/aphia.php?p=taxdetails&id=196387

 

 

8 hours ago, doushantuo said:

this links to Pilsbry and Sharp

The type species of Polyschides Pilsbry & Sharp is apparently Cadulus tetraschistus Watson 1879(by original designation)

the name change might be in:

Henderson, J. B. 1920. A monograph of the east American scaphopod mollusks. U. S. Nat. Mus. Bull. Ill: 177 p., 20 pis.??
 

 

Thanks for this info, but Maybe I should have been more precise in what I was asking. While I did find numerous other species within the Genus Polyschides, my question is / was specifically about species thallus. This is the one that everything I see online shows it in the Genus Cadulus, where my reference at home shows it in the Genus Polyschides.

@DPS Ammonite I had and still continue to scour the WoRMS website, but as of yet I can find no mention of thallus there. Fossilworks puts it in genus Cadulus.

@doushantuo interesting read.

 

[sixgill pete]

@MikeR any thoughts on this?

[doushantuo]

Pete :i noticed a not unreasonable similarity between C. thallus. and C.subfusiformus 

You might need a morphometric approach to separate them,if they are even separate species.

The Florida Geol.Survey has a paper which MIGHT illuminate matters further

 

Mu italian is reasonable ,but...

European scaphopods

Boll. Mus. reg. Sci. nat. Torino Voi. 9 - N. 1 pp. 105-172 27-2-1991

Giulio Pavia I molluschi del Messiniano di Borelli (Torino). 2. Scaphopoda.

[MikeR]

6 hours ago, sixgill pete said:

@MikeR any thoughts on this?

 

Hi Don

 

Funny that you posted on this topic as I have been working on my Tar River material from the one site I collected in October and just completed cataloging yesterday, finding Caldulus thallus there as well.  WoRMS lists both Cadulus and Polyschides as valid.  Polyschides was at one point a subgenus of Cadulus in which some researcher split into its own genus and whose work was accepted by WoRMS.  So what are the differences in Polyschides to separate it from Cadulus?  In his description of the gastropods and scaphopods of the Choctawatchee Formation (now known as the Jackson Bluff Formation),  W.C. Mansfield listed two species of Cadulus, C. thallus and C. (Polyschides) cf. qudridentatus.  In his discription of the latter, he notes that the apex has four slits.  With this information I searched for publications describing Polyschides and came across a paper about Brazilian Gadilidae.  Instead of boring you with a link to a publication describing the morphometrics of tiny scaphopods I have attached a picture from it which shows differences between several different species and the slits present in Polyschides.  I was also able to find other examples of Polyschides with said slits.

 

 

Based on this I think that Cadulus thallus is correct and the NCFC publication is in error calling it Polyschides.

 

Mike

[doushantuo]

some subfusiformis:

Image to the right from Nickles* review of extant African scaphopoda

*Maurice NICKLÈS  

Bull. Mus. natn. Hist, nat., Paris, 4 e sér., 1, 1979,section A, n° 1 : 41-77. 

 

fun fact:the type species of Polyschides seems to be Siphonodentalium tetraschistum

some biometrical indices:

Shimek/The Veliger/1989i

 

 

 

 

c to e : Australian Polyschides

[sixgill pete]

4 hours ago, MikeR said:

 

Hi Don

 

Funny that you posted on this topic as I have been working on my Tar River material from the one site I collected in October and just completed cataloging yesterday, finding Caldulus thallus there as well.  WoRMS lists both Cadulus and Polyschides as valid.  Polyschides was at one point a subgenus of Cadulus in which some researcher split into its own genus and whose work was accepted by WoRMS.  So what are the differences in Polyschides to separate it from Cadulus?  In his description of the gastropods and scaphopods of the Choctawatchee Formation (now known as the Jackson Bluff Formation),  W.C. Mansfield listed two species of Cadulus, C. thallus and C. (Polyschides) cf. qudridentatus.  In his discription of the latter, he notes that the apex has four slits.  With this information I searched for publications describing Polyschides and came across a paper about Brazilian Gadilidae.  Instead of boring you with a link to a publication describing the morphometrics of tiny scaphopods I have attached a picture from it which shows differences between several different species and the slits present in Polyschides.  I was also able to find other examples of Polyschides with said slits.

 

 

Based on this I think that Cadulus thallus is correct and the NCFC publication is in error calling it Polyschides.

 

Mike

Thanks Mike, great information. I agree, that based on all of it that Cadulus is the correct Genus. I hope you had a good Christmas, hopefully sometime soon the water levels will go back down in the Tar.