Gray-foot lancetooth snails are 11 to 21 mm in diameter, with 4.5 to 5.5 spirals in their shells. The height of an adult shell ranges from 5 to 10 mm. Their shells, which are shades of white, greenish, tan, or yellow, are glossy and smooth. The shell shape is round or flat like a disc. The shell opening is crescent-shaped. Within the shell, gray-foot lancetooth snails have a thick, coarse skin, which may be checkered in appearance. Two pairs of tentacles are found on the head, and the body is broad and heavy. There is a flap of skin on the right part of the neck. (Burch and Jung, 1988; Pilsbry, 1946)
Haplotrema concavum, also known as the gray-foot lancetooth snail, lives in the eastern United States and southeastern Canada. These snails are found from Maine and central Ontario south to Florida's panhandle. They are found as far west as eastern Iowa and eastern Texas (with small populations reported in a few areas farther west), and as far east as the coastline of the Atlantic Ocean. ("Haplotrema concavum Say, 1821", 2013; "Haplotrema concavum", 2003; Hubricht, 1985)
Gray-foot lancetooth snails live in moist areas of forests, as well as river valleys. They are often found around plants such as cinnamon fern (Osmunda cinnamomea), Virginia creeper (Parthenocissus quinquefolia), bracken fern (Pteridium aquilinum), greenbrier (Smilax rotundifolia), and poison ivy (Toxicodendron radicans), and are also found in debris on the forest floor, and on the underside of logs. (Burch and Jung, 1988; Hubricht, 1985; Painter, 2013)
Land snails lay their eggs in moist areas, and produce a sticky substances that makes their eggs stick to surfaces. The eggs usually hatch after 7 to 10 days, but this depends on moisture and temperature. The snails grow, and they are considered adults when the outer lip on the opening of the shell forms. ("Illinois Snails and Slugs", 2009; Burch and Pearce, 1990)
Gray-foot lancetooth snails are hermaphrodites, meaning that each individual snail has both male and female genitalia. Mates may be found by following the mucus trails snails leave behind. The snails typically perform a courtship ritual before mating. After the ritual takes place, one snail climbs on top of the other snail. The snails gnaw on each other for a few minutes before each snail inserts its male genitalia into the other snail. Mating can last for a long time; in one instance it was observed going on for 10 hours. Afterwards, the snails separate, and both will lay eggs. (Burch and Pearce, 1990; Tompa, 1984; Webb, 1943)
In addition to two snails mating, gray-footed lancetooths are also able to reproduce by self-fertilization. Since the snails have both male and female parts, a snail is sometimes able to use its own sperm to fertilize its own eggs. Mating is likely to be most common during the warmer months of the year, and the snails also mate more when it is raining. Land snails lay about 20 eggs at a time. Snails are able to mate when the lip at the opening of the shell forms. In cooler or drier regions, growth can take longer, so snails are not able to mate until later in life than snails that live in warmer regions. ("Illinois Snails and Slugs", 2009; Burch and Pearce, 1990; Tompa, 1984; Webb, 1943)
Land snails lay their eggs and then leave. They provide no parental care. ("Illinois Snails and Slugs", 2009)
Gray-foot lancetooth snails probably live about 1 to 2 years. ("Haplotrema concavum", 2003)
Gray-footed lancetooth snails are nocturnal, and are also more active when the temperature is cooler and humidity is higher. To survive the winter, land snails can decrease the amount of water in their body and form a membrane over the opening of the shell. This membrane prevents any further water loss. This membrane can also be produced during dry conditions, to seal off the shell and keep moisture in. As predators, gray-foot lancetooth snails are more solitary than other land snails. (Atkinson, 2013; Burch and Pearce, 1990; Pearce, 1989)
Home range size is unknown for this species, but other related land snails live in about 40 square meters of space. (Pearce, 1990)
Land snails leave mucus trails, which are used as a form of communication. The mucus allows the snails to detect their own species (to find mates) and other species. Gray-foot lancetooth snails are known to follow mucus trails of their prey. The front tentacles of these snails detect chemicals. These snails can find food by using their sense of smell. Eyes located at the tops of the tentacles can detect light and may also be used for sensing forms at night. (Atkinson, 2013; Burch and Pearce, 1990; Nordsieck, 2011)
Gray-foot lancetooth snails are carnivores, and feed mostly on other snails. They also chew on dead shells to get calcium. They will cannibalize their own species, but studies have shown that these snails prefer young snails of other species, such as flamed discs (Anguispira alternata). Younger individuals will eat the eggs of their own and other species, but begin to eat whole snails once reaching 6 to 7 mm in diameter. Gray-foot lancetooth snails prefer larger prey items with softer shells, such as juvenile oval ambersnails (Novisuccinea ovalis). This species will also eat nematodes and plants. To catch their prey, gray-foot lancetooth snails follow their slime trails. They attack smaller prey by climbing on top or turning the shell. To attack larger snails, they crawl inside their prey's shell. The snail may eat its prey there, or move it to another location by dragging it along. A meal may take several hours to eat. (Atkinson and Balaban, 1997; Atkinson, 1998; Hotopp, 2006; Hubricht, 1985; Painter, 2013; Shearer and Atkinson, 2001)
In general, land snails are preyed on by lampyrid beetle larvae and other insects, birds, reptiles, rodents, and other small mammals, particularly voles and shrews. (Burch and Pearce, 1990; Painter, 2013)
Gray-foot lancetooths are predators of other snails, and are also prey to a number of other insects, birds, reptiles, and small mammal predators. They may also carry brain worms (Parelaphostrongylus tenuis), which cause a disease called cerebrospinal nematodiasis in various hoofed animals. (Burch and Pearce, 1990; MDNR wildlife diseases laboratory, 2013)
Gray-footed lancetooth snails do not cause any problems for humans. (MDNR wildlife diseases laboratory, 2013)
Gray-foot lancetooth snails eat some snail species that can do damage to crops. By preying on these snails, gray-foot lancetooth snails decrease crop damage. ("Haplotrema concavum Say, 1821", 2013)
Gray-foot lancetooth snails are not an endangered species. (IUCN, 2013)
Renee Mulcrone (author), Special Projects, Jeremy Wright (editor), University of Michigan-Ann Arbor.
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