Land Snails
Photo(s): Views of a Strobilops affinis shell © D. Dourson
Click photo(s) to enlarge.
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Strobilops affinis (Pilsbry, 1893)
Family: Strobilopsidae
Common name: Eightfold Pinecone
Identification
Width: 2.7 mm
Height: 2.5 mm tall
Whorls: 6
Strobilops affinis is a dome-shaped shell sculptured with minute transverse ribs. The aperture has a reflected edge and the umbilicus is perforate to umbilicate. Elongated lamellae are visible in the aperture. Within the interior are a series of rather short, nearly equal-length lamellae that can often be seen through the bottom of live and fresh-dead shells.
Ecology
This species is found on logs during wet weather and on leaf litter during drier parts of the year, in mixed hardwood forests (Hubricht, 1985). It is also reported from grassland and fen habitats in association with marl beds (NatureServe, 2017).
Taxonomy
There are no synonyms.
Distribution
Strobilops affinis ranges from Missouri and Minnesota east to Pennsylvania, Massachusetts, Maine and New York, but more sparsely in the east. It is reported it from four counties in New York based on museum records (Hotopp and Pearce, 2007). It is listed as Critically Imperiled in Pennsylvania.
This enigmatic species was previously reported in West Virginia by multiple investigators but never by Hubricht, who spent a fair amount of time in the state. His closest records were from Meigs County, Ohio. Specimens examined from the Carnegie Museum labeled as this species were either S. aeneus or S. labyrinthicus, therefore its occurrence in West Virginia remains doubtful (Dourson, 2015).
Conservation
NatureServe Global Rank: G4, apparently secure. NatureServe State Ranks: Pennsylvania, S1; not ranked in several other states.
Dan Dourson, Ken Hotopp 6/2017
