Anguispira - Tigersnails (Family Discidae)
a juvenile Flamed Tigersnail
Tigersnails have the largest shells in this family. Two species have been widely collected in Indiana, the Flamed Tigersnail (Anguispira alternata) and the Banded Tigersnail (Anguispira alternata). Notable traits include the very open umbilicus, simple apertural lip, and radial reddish-brown striping.
Discus, the Disc snails, are in the same family and are also found in Indiana but are quite different in appearance, being smaller and more depressed.
Anguispira alternata (Say, 1816)
Flamed Tigersnail
Anguispira alternata (Say, 1816)
Family Discidae
Identification: Heliciform, simple lip, globose to subglobose, > 10 mm diameter, up to 23 mm diameter. This species has a wide umbilicus and incomplete reddish-brown stripes (more like “blotches”) on a yellowish background. Small specimens of Anguispira alternata are generally similar to the adult, but the edge of the body whorl tends to be more angular than round.
Comparisons: Anguispira kochi (the Banded Tigersnail) is more globose, while Anguispira alternata is more subglobose. Both have reddish-brown markings on the shell, but those of Anguispira alternata are more like blotches on a yellowish background compared to the more solid color bands (which may be weaker) on Anguispira kochi. Their adult size probably overlaps.
Habitat: Tigersnails are a forest species, either floodplain or upland, associated with logs, rotting and hollow trees, leaf litter, and rocks and outcrops. They are also found in verge-like areas such as weedy roadsides and along railroads but also in residential areas in and around gardens and outbuildings. Both species overlap in range and can probably be found in the same habitat.
Status: It has been collected in most all parts of the state, overlapping many counties with Banded Tigersnail.
The hatchlings, with eggs, look just like the adults, only smaller. The edge of the last whorl in some may be slight sharper (more “angular”), less rounded.
Anguispira kochi (Pfeiffer, 1821)
Banded Tigersnail
Anguispira kochi (Pfeiffer, 1821)
Family Discidae
Identification: Heliciform, simple lip, globose to subglobose, > 10 mm diameter, up to 23 mm diameter. This species has a wide umbilicus and reddish-brown stripes on a yellowish background.
Habitat: Tigersnails are a forest species, either floodplain or upland, associated with logs, rotting and hollow trees, leaf litter, and rocks and outcrops. They are also found in verge-like areas such as weedy roadsides and along railroads but also in residential areas in and around gardens and outbuildings. Both species overlap in range and can probably be found in the same habitat.
Comparisons: Anguispira alternata is more subglobose than A. kochi which is more globose. The reddish-brown markings on the shell of A. kochi are more like solid bands compared to the blotch-like markings of A. alternata. Their adult sizes probably overlap.
Status: It has been collected in most all parts of the state, overlapping many counties with Flamed Tigersnail. In the USA, its distribution differs a bit.
