RARE SNAILS IN OUR PARKS

TWO VERY UNCOMMON SNAIL SPECIES ARE WHY TWIN HILLS BECAME A DESIGNATED NATURAL HERITAGE AREA IN 2021

LITTLE SNAILS, BIG DEAL

Many of us love walking in Twin Hills Park, a 25-acre park located in the North Meadowcroft neighborhood of Mt. Lebanon. Preservation of the natural landscape here is crucial because of two tiny mollusk species.

Twin Hills was designated as a globally significant Natural Heritage Area in 2021 because the Maryland Glyph and Armed Snaggletooth live here — and very few other places… in the world!

The Maryland Glyph, above left, is about the size of a sesame seed. It is a burrowing species that survives in an area with calcified limestone. It is considered globally imperiled. The Armed Snaggletooth, above right, is smaller than a grain of rice.

The designation of Twin Hills Park as a Natural Heritage Area was part of the 2021 Allegheny County Natural Heritage Inventory conducted by the Western Pennsylvania Conservancy, with the assistance of Dr. Tim Pearce, head of the section of Mollusks at Carnegie Museum of Natural History. Dr. Pearce said the two species also were found at Robb Hollow Park, which means that park also might qualify to be designated a Natural Heritage Area.

The map of Twin Hills below and Natural Heritage information presented here are provided by Anna Johnson and Christopher Tracey, editors of the 2021 Allegheny County Natural Heritage Inventory, PA Natural Heritage Program. View the Twin Hills Park pages of the Allegheny County inventory here:

https://www.naturalheritage.state.pa.us/cnhi/cnhi/TwinHillsPark_20210113094706.pdf