A few months ago I posted the following regarding some Florida littorinids.
If the whole piece does not go thru and you'd like to see it, email me
directly. My request for comments still stands.
I'm integrating the Florida material a generous friend gave me into my
collection of FL marine seashells. Our collections span about 15 years of
field collecting and all of Florida. Currently, I'm working with some
common Nodilittorina. Most current references rely upon Bandel, K. & D.
Kadolsky. 1982, Western Atlantic species of Nodilittorina, The Veliger
25(1):1-42, a copy of which I do not have and have not read. The species
presenting the identification problem are angustior, interrupta, lineolata,
mordax, riisei, and ziczac. Four of these (interrupta, lineolata, mordax,
riisei) are essentially indistinguishable. To resolve the issue I reviewed
several references and have concluded as follows.
Abbott's reference to lineolata is in error and is most probably riisei.
Lineolata is now considered restricted to Brazil/Uruguay.
Abbott does not list mordax, which is consistent with Redfern's comments
that it is found in the Bahama's and Curacao. Mordax is considered as
indistinguishable from riisei, with riisei ascribed to Florida, Nicaragua
and Cuba. These two may one day found to be the same.
This brings us to interrupta, which Harry Lee considers to be the Florida
species rather than riisei. Harry is not often wrong, but Bandel and
Kadolsky placed interrupta in Jamaica, Haiti, Antilles, Costa Rica and
Columbia.
Neither Mollusks, 2nd Ed. or The Academy of Natural Sciences of
Philadelphia's Malacolog include interrupta or mordax as occurring in North
America. Both list riisei.
Therefore, I'm confronted with three species to separate and identify -
angustior, riisei, and ziczac. Here's my collecting data and observations.
Angustior. Samples found from Sebastian Inlet south to Dade County, the
Keys, none along west coast, then from Taylor County in the eastern
panhandle west to Pensacola. Harry Lee considers angustior essentially
indistinguishable from riisei (his interrupta). Redfern distinguishes
mordax(indistinguishable from riisei) from angustior with mordax having one
white band at bottom of interior of mouth and angustior as having two bands.
I have not found this to be a consistent distinguisher. Redfern notes that
angustior has a stronger cord around the bottom of the body whorl giving it
a sharper angled profile (than riisei, and ziczac) and causing a notch to
appear on the inside of the lip. He also describes angustior's teleoconch
whorls as only slightly convex. In my observations riisei's teleoconch
whorls are consistently more convex than angustior's. I'd characterize
angustior as almost straight sided, riisei as somewhat convex, and ziczac as
distinctly convex. As a result angustior appears more narrow with a high
spire and ziczac appears rounded and stout, with riisei falling in between
and often too close to angustior to distinguish on this character.
Riisei. Samples found all along Florida's east coast from Nassau County
south to Dade County. None in the Florida Keys (Monroe County). On west
coast of Florida from Collier County north to Tarpon Springs, then in the
panhandle from Franklin County west to Santa Rosa County. Riisei's cord
around the bottom of the body whorl less pronounced than angustior and does
not create a notch to appear on the inside of the lip. Profile of
teleoconch more convex than angustior.
Ziczac. Samples found along Florida east coast from Sebastian Inlet south
to Dade County and the Florida Keys. None on west coast. Ziczac easily
distinguished from riisei and angustior. It is larger (20mm vs 16/17),
profile of teleoconch distinctly more convex, cord around the bottom of the
body whorl indistinct and as Redfern notes its appearance is predominantly
grayish white with much narrower oblique brown lines. Also, when looking at
the shell from the mouth side, count the spiral groves from the top of the
lip to the suture. Ziczac has about 24 finer groves than riisei's and
angustior's 8 to 10 wider and deeper grooves.
So, this is how I've attempted to distinguish among three Florida
Nodilittorina. I'm soliciting comments and critique from others who have
experience with them.
Marlo
-----Original Message-----
From: Conchologists List [mailto:[log in to unmask]] On Behalf Of
aydin
Sent: Thursday, May 04, 2006 9:47 AM
To: [log in to unmask]
Subject: Littorinidae of FL
Is there a key (published or on the Internet) available for the
littorinids of Florida?
Aydin
snailstales.blogspot.com
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