Tag Archives: Poecilozonites nelsoni ssp. callosus

Poecilozonites nelsoni ssp. callosus Gulick

Callose Bermuda Land Snail (Poecilozonites nelsoni ssp. callosus)

The Callose Bermuda Land Snail was described in 1904 as a ‘variety’ of Nelson’s Bermuda Land Snail (Poecilozonites nelsoni (Bland)).

This form differs from the normal form by its smaller size and some other characters, the author writes the following lines.:

Shell smaller than the typical form, shiny, with heavy ribbed striae, colored with a broad yellowish-brown peripheral band on a white ground. Whorls a trifle more than nine, increasing regularely and very gradually. The suture does not change ist character nor become deflected from the peripheral line of the preceding whorl. The usual peripheral angle is almost obsolete. The base has a stronger angle about the umbilical perforation than is usual in the species. The peristome is greatly thickened on the inside from 1 mm. at the suture to fully 2 mm. near the columella. A prominent callosity covers the parietal wall of the aperture.” [1]



[1] Addison Gulick: The fossil land sanils of Bermuda. Proceedings of the Academy of Natural Sciences of philadelphia 56(2): 406-425. 1904


Photo from: ‘Stephen Jay Gould: An volutionary microcosm: Pleistocene and recent history of the land snail P. (Poecilozonites) in Bermuda. Bulletin of the Museum of Comparative zoology 138(7): 407-531. 1969’

(under creative commons license (3.0))


edited: 13.06.2020