Six-toothed Saint Helena Snail (Helenoconcha sexdentata)
The Six-toothed Saint Helena Snail was described in 1893, as its name implies, it is, or rather was, endemic to the island of saint Helena.
“This species agrees rather closely with P. pseustes, Smith, in respect of the dentition of the aperture. The palatal lamella, however, in that species is considerably stronger, and the form of the shell is very different. P. cutteri has two similar parietal lamellae, only two basal denticles, and no palatal lamella. In other respects it appears to be very similar, but a trifle larger. Watercresses (Nasturtium officinale) among which it is stated by M. Eudel [M. Emile Eudel, the collector of this species] that this species occurs, are said to be “very common in the ravines and along the mountain streams and ponds.”.” [1]
The shells reach sizes of about 0,3 cm in diameter.
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The Six-toothed Saint Helena Snail was apparently still found alive when it was described; it is nevertheless now considered extinct. [1]
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The species of this genus, as well as basically all of the Saint Helena Gastropoda species, are in urgent need of a proper revision!
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References:
Edgar A. Smith: Descriptions of two new species of Patula from St. Helena. The Conchologist 2(7): 164-165. 1893
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(public domain)
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edited: 29.05.2021