Inflectarius - Shagreen Snails (Family Polygyridae)
Inflectarius is a genus of depressed shells with a somewhat pill-shaped body. The shell has fine hairs, is imperforate, has a long curved parietal tooth, and two apertural teeth. The aperture is rounded but smaller than most, while not quite as narrow as Euchemotrema or Stenotrema.
Two species are recorded from Indiana. Inflectarius inflectus (Shagreen Snail) is the most common with Inflectarius rugeli (Deep-tooth Shagreen Snail) found in only three counties.
Identification:
1a. basal tooth small and maybe more pointed and visible, palatal tooth larger and more recessed, shell 7-16 mm in diameter – Inflectarius rugeli
1b. basal tooth narrow, palatal tooth blunt, smaller, and only slightly recessed, shell 7-14 mm in diameter – Inflectarius inflectus
Inflectarius inflectus (Say, 1821) with mm scale
Shagreen
Inflectarius inflectus (Say, 1821)
Characters: Heliciform, reflected lip, subglobose to depressed, imperforate. ~7-14 mm in diameter. The genus has a long curved parietal tooth, and two apertural teeth, one long basal and one blunt and recessed palatal; about 5 closely coiled whorls; surface with fine hairs.
Comparisons: The Shagreen and the Deep-tooth Shagreen Snail (Inflectarius rugeli) are similar, but the basal tooth may be more pointed in the Deep-tooth and the palatal tooth is larger and deeper in the Deep-tooth.
Habitat: Oesch et al. (2013) report it in mesic woodland habitats, common in moist leaf litter around bluffs and talus; as a troglophilic (cave) species and one of the most frequently encountered gastropods in Missouri caves. The shagreen is also found in urban areas. On the other hand, Dourson (2015) reports it as not a species of mature woods, but rather of “roadside ditches, railroad rights-of-way, grassy areas, and shale banks of road cuts.”
Status: This is the most widely distributed of the three species of Shagreen snails.
Deep-tooth Shagreen Snail
Inflectarius rugeli (Shuttleworth, 1852)
Characters: Heliciform, reflected lip, subglobose to depressed, imperforate. ~7-16 mm in diameter. The genus has a long curved parietal tooth, and two apertural teeth, one long basal and one large and recessed palatal; about 5 closely coiled whorls; surface with fine hairs. Find images and descriptions at Hotopp et al. (2013).
Comparisons: The Shagreen and the Deep-tooth Shagreen Snail are similar, but the basal tooth may be more pointed in the Deep-tooth and the palatal tooth is larger and deeper in the Deep-tooth. No information is at hand for the Smooth-lip Shagreen Snail.
Habitat: mixed hardwoods, under leaf litter and logs and along forested road edges, a species of mature woods (Dourson 2015).
Status: The Deep-tooth Shagreen has only been collected in 3 counties and the Smooth-lip in two. But the Smooth-Lip is way out of its range and the identification should be confirmed
Other Species in the Databases
A third species in the database is Inflectarius edentatus (Smooth-lip Shagreen Snail).
Smooth-lip Shagreen Snail
Inflectarius edentatus (Sampson, 1889)
Very little to no information is at hand for the Smooth-lip Shagreen Snail, Inflectarius edentatus. No images were found. If the identification is correct, it is out of range. Two observations are from different collectors in the 1930s.
Oesch (2013) notes this species is similar to Inflectarius inflectus, but has a greatly reduced lip lamellae. It might have been misidentified. Hubricht (1985) notes this species is “found under rocks and logs on wooded hillsides”.
