Posted: May 9 2009

 Ithycythara parkeri Abbott, 1958, Parker's Mangelid

On May 12, 2009 I posted the following inquiry on Conch-L"

"Abbott indicated that I. parkeri was "common." However, it appears this is a sublittoral species and probably rarely found except as a beach shell.


The one specimen I have was collected at the artificial and unique Inlet habitat at Palm Beach and is not representative of normal habitat for many, many of the species collected there. I was wondering if anyone has had the good fortune to collect this shell live anywhere in Florida by any means?"

5/12/2009 8:14 AM -
Hary Lee was the first to comment:

"Dear Marlo,

Great images. I especially like the detail of the protoconch and labral denticles.

In the Jacksonville, Florida area we find shells which are likely the same species as your specimen. We have recorded a total of about a dozen examples from only three stations, between 30 and 45 meters in depth (32 to 55 nautical miles E of the coast), by scallop trawl and by small dredge.

On typological grounds I have been calling them Ithycythara rubricata (Reeve, 1846). Three other available names must be considered for these shells, which have six axial ribs, variably-developed red-brown flammules, especially on the latter third of the body whorl, and fine spiral ridges. A while back I examined a series of shells, apparently belonging to this species but collected in the Exumas, Bahamas (Dieter Cosman Coll). Specimens had shells with 5.5 to 8.5 axials on the body whorl. This observation calls into question the distinctions among I. pentagonalis (Reeve, 1845), I. auberiana (dOrbigny, 1847), I. parkeri Abbott, 1958, and this taxon. It may be that I. pentagonalis is the proper assignment and the others are synonyms."

5/12/2009 9:25 AM -
Linda Bush reported:

"I am pretty sure that I had this species in dredgings, in the days when you could get them. I have traded most of my small shells for Pectinidae, so I cannot check."

5/12/2009 10:29 AM -
Peggy Williams added to Harry's comments with:

"I agree with Harry that Marlo's shell is more likely rubricata and that pentagonalis and auberiana may be synonymous (in fact, someone has determined so, since Malacolog has them synonymized.) But I think parkeri is distinctly more slender and has fewer ribs than the others."

(
Marlo's comment: Malacolog synonymizes Pleurotoma pentagonalis Reeve, 1845 with Ithycythara auberiana (d'Orbigny, 1847) with I. auberiana as senior. Malacolog treats I. parkeri and I. rubricata as full species without synonyms. Searches of the Florida Museum of Natural History’s Invertebrate Zoology Master Database and the Bailey-Matthews Shell Museum Database revealed no records of any of these four names.)

5/12/2009 11:45 AM -
Harry added:

" Dear Peggy, Marlo et al.,

Reeve (1845: sp. 255) and Abbott (1958: 96) described shells with five axial ribs. Abbott failed to compare his species with Reeve's. I agree that the profile of the Abbott's species (type figure) is a bit stouter.

Reeve, L., 1843-1846. The genus Pleurotoma. Conchologia Iconica 1: 40 pls., facing text blocks + index. Jan. -Apr.
Abbott, R. T., 1958. The marine mollusks of Grand Cayman Island, British West Indies. Monographs of the Acad. Nat. Sci. Phila. 11: vi + pp. 1-138 + 5 pls. + index."


Marlo's Comment: Thanks to all for comments and hopefully there will be more. Harry's and Linda's comments appear to confirm that I. parkeri is a sublittoral species and probably collectable as a live shell only when dredged, but for exceptional circumstances. As to the name issue, I'll stay with I. parkeri until DNA based research sheds more light on the matter.

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