Costoanachis sparsa vs scutulata

[Marlo]

Costoanachis scutulata (Reeve, 1859)
Costoanachis sparsa (Reeve, 1859)

Costoanachis scutulata in Florida is often mistaken for C. sparsa for two reasons. None of the most popular books (Abbott, Redfern, others) include C. scutulata. Radwin (The family Columbellidae in the western Atlantic part IIa - the Pyreninae. The Veliger 20(2): 119-133. Oct. 1, 1977.) erroneously restricted C. scutulata to Bermuda and no one yet has questioned this error in the literature.

Reeve's descriptions of these two species is useless. His descriptions were as follows:

sparsa - Shell fusiformly ovate, longitudinally finely ribbed, interstices cancellated, yellowish, sprinkled with chestnut dots and network, aperture small, lip varicose, notched at the upper part, denticulated within.

scutulata - Shell ovate, fulvous-chest-nut, promiscuously tessellated with white, whorls longitudinally ribbed, the last smooth, grooved at the base; aperture small, lip notched at the upper part,denticulated within.

However, Radwin did a pretty good job of describing the two and distinguishing between them. Following are his descriptions followed by some of my own observations, particularly the protoconch differences emphasized to me in communications from Dr. Harry Lee.



Based upon review of material collected in the Florida Keys and the Bahamas [see Redfern's C. sparsa (#414), which is an apparently misidentified C. scutulata - note the extreme simitarity between Redfern's description of his sparsa and Radwin's scutulata] is not restricted to Bermuda. There are several differing characters between the two species. However, the most reliable character that clearly distinguishes between scutulata and sparse is the protoconch.

Palm Beach Inlet, FL.



C. scutulata, Key Largo, Florida Keys.


C. scutulata, Key Largo, Florida Keys.

Pagin down two posts to see images of Costoanachis scutulata that but for the protoconch could easily be mistaken for C. sparsa.

[HerbC]

Marlo: Thank you for the differentiation. Please amend my Florida Keys micros list from C. sparsa to C. scutulata. I'd not seen C. scutulata until you provided these photos, and there's no question about the difference.

Thanks,

Herb Chapin

Marlo: Done!

[Marlo]

The following images are of color variations of Costoanachis scutulata that closely mimic C. sparsa. Like C. sparsa the white background predominates and some spiral grooves are visible on later whorls. Subsutural depression absent. These shells display almost all the exceptions to the more common C. scutulata that cause confusion with C. sparsa. However, the protoconchs tell the story. Less than two whorls before the teleoconch begins.

Both were collected at north end Julia Tuttle Causeway, Miami Beach, Florida. Collected by Phil Poland; digital images by Marlo Krisberg. I apologize that the protoconchs are not well captured.

*

[gwatters]

Now that we've opened Pandora's box with the sparsa - scutulata discussion, how about comparisons with pretrii and hottessieriana?

[Marlo]

Howdy Tom,

Great to see you back on LTS. Did you review my presentation on Terebra protexta (and vinosa)?

I have only a very few specimens of S. pretrii from SE Florida and no S. hotessieriana at all, nor ever seen one. So, I can do some images of the former, but not the latter. In any event, it would be a little time as the calendar is full.

marlo

[Marlo]

Well, Tom, it's only been two years, but here's something to close the loop. I haven't done C. sparsa yet, but give me another two years.