Posted: Feb 4 2015

Seila adamsii (H. C. Lea, 1845), Adam's Miniature Cerith

This is a long presentation with 3 galleries.  Be sure to scroll down and see everything.

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Notice of this presentation was posted on Conch-L 2/4/15. I am recording here a lengthy commentary by Harry Lee so that his valuable information is preserved in proximity.

"A few observations:

Like Marlo's, Marcus' images are high-quality and depict unusually well-preserved specimens. All those with intact protoconchs seem to be close to or the same as the morph Marlo has nominated for C.B. Adams' species (simply renamed by H.C. Lea because of homonymy) described from MA. Olsson and Harbison (1953: 302) mentioned this 2-3 whorled p'conch morph as present in W FL waters but absent from the Plio-Pleistocene of St. Petersburg, FL. Redfern (2013: 142; fig. 409A, , Lyons (1989: 14, pl. 5, fig 8), Lee (2009: 88), and Rolán (pers. comm., have also reported material consistent with Marlo's nominee, which may have a pretty extensive geographic and bathymetric range in the Holocene.

I have been working with Lower Pinecrest (~3 Ma) micromollusks for a over a year now and have not seen this morph in that context, which absence supports the Olsson and Harbison (O&H) observation and may indicate a later origination. However, I have turned up three distinct protoconch morphologies, one of which is consistent with the O&H morph and a second which is the spitting image of S. adamsii sensu Thiriot-Quiévreaux, 1980,* which work Marlo includes in his treatment. Furthermore, it is consistent with Marlo's PW4.5 morph he so exhaustively treated.

Marlo refers to some nagging incompatibilities between the two morphs treated by Lee (op. cit.) and his two. I'd like to ease his anxiety; I'm nearly certain That Lee called the 2.5 whorled protoconch "paucispiral," and his other morph was consistent with PW4.5. Unfortunately higher resolution versions of the images used in Lee's work were destroyed in a flood event.

As I pointed out in an earlier rant on this species, such musings as above, while having some bearing, do nothing to solve the identity problem of S. adamsii, a synonymy of which, adopted from L. Campbell (1993) and a few other sources, follows:

[HOLOCENE] Cerithium emersonii var. C.B. Adams, 1839 http://www.biodiversitylibrary.org/item/10...ge/287/mode/1up

[HOLOCENE] Cerithium terebrale C.B. Adams, 1840 http://www.biodiversitylibrary.org/item/97...ge/395/mode/1up
non Lamarck, 1804. Lectotype: Clench and Turner (1950: pl. 37, figs 5-7).

[FOSSIL] Cerithium clavulus H.C. Lea, 1843; see Lea, 1845 http://www.biodiversitylibrary.org/item/70...age/50/mode/1up with plate 37, fig. 89 http://www.biodiversitylibrary.org/item/70...age/63/mode/1up non Eude-Deslongchamps, 1842.

[HOLOCENE] Cerithium terebellum C.B. Adams, 1847 http://www.biodiversitylibrary.org/item/44...age/23/mode/1up
replacement name for C. terebrale C.B. Adams, 1840 non Brown, 1831.

[FOSSIL] Cerithium annulatum Emmons, 1858 http://www.biodiversitylibrary.org/item/58...ge/291/mode/1up ; fig. 161 http://www.biodiversitylibrary.org/item/58...ge/290/mode/1up
non Zekel, 1852.

Among the above descriptions the only mention of a protoconch is by Lea (1843, 1845), who indicated not one of his 50-odd specimens possessed that feature.

A few years back, we reflected on the identity of Cerithium greenii C.B. Adams, 1839 in this forum and LTS. That orphan name found an identity after near-topotypical material with intact protoconchs came to light; see http://z14.invisionfree.com/Conchologist_F...?showtopic=1875 . Déjà-vu all over again?

* Regrettably, her name for a second Seila morph with deeper sutures and a cylindrical vs. conical profile, S. adamsii var. beaufortensis, is unavailable under the provisions of Article 45 of the Code. Too bad."

Jim Carlton's S. adamsii from Conn..JPG