Fresh Water Gastropods

Middle Miocene Barstow Formation--15 Million Years Old

Fossil Bone Basin, Mojave Desert, California

Fossil fresh water gastropods (snails) from the middle Miocene Barstow Formation, Fossil Bone Basin, Mojave Desert, California. Largest of the specimens is approximately a half inch in diameter (12.7mm); called scientifically Helminthoglypta alfi. Its closest living relative presently inhabits the area around Victorville, California, Mojave Desert, "on dry rocky mountains slopes, among boulders and in rock slides or under rocks and leaves beneath cottonwood trees along the Mojave River." Quote is from a specific public domain document. Photograph courtesy the California Academy of Sciences, per the parameters defined in the Creative Commons license. I edited and processed the image through photoshop.

Three views of the same fossil fresh water gastropod (snail) from the middle Miocene Barstow Formation, Fossil Bone Basin, Mojave Desert, California. It's approximately 15 million years old, called scientifically Helminthoglypta alfi. An image taken from a specific public domain document. Actual width of original specimen is 23 millimeters (.91 of an inch). Its closest living relative presently inhabits the area around Victorville, California, Mojave Desert, "on dry rocky mountains slopes, among boulders and in rock slides or under rocks and leaves beneath cottonwood trees along the Mojave River." Quote is from the specific public domain document from which the image came.

Two fossil fresh water gastropods (snails) from the middle Miocene Barstow Formation, Fossil Bone Basin, Mojave Desert, California. An image taken from a specific public domain document.

Left to right: Left and middle are two views of the same fossil fresh water gastropod (snail) from the middle Miocene Barstow Formation, Fossil Bone Basin, Mojave Desert, California. It's approximately 15 million years old, called scientifically Lymnaea mohaviana. Actual length of original specimen is 27 millimeters (1.06 inches). Its closest living relative presently inhabits southern California and at high altitudes in Arizona; "found plentifully in bodies of water of greater or less size, on floating sticks and submerged vegetation, on stones and on the muddy bottom. Inhabits both clear and stagnant water, but prefers a habitat in which the water is not in motion." Quote from Baker, F.C. 1911, "The Lymnaeidae of North and Middle America, recent and fossil": Chicago Acad. Sci. Spec. Pub. 3 xvi, 539, 58 pl.

Far right is a fresh water gastropod (snail) called Lymnaea magasoma, roughly 15 million years old, from the middle Miocene Barstow Formation, Fossil Bone Basin, Mojave Desert, California. Actual length of original specimen is 33 millimeters (1.3 inches). It's closest modern ancestor lives from northern New England and the Great Lakes region northward to Hudson Bay. "At Tomahawk Lake, Wisconsin megasoma lives in swampy portions of sheltered bays where the water is quiet. The bottom of such a habitat is boggy and the water is so shallow that frequently little boggy islands are formed, and on these megasoma may be found, one or two specimens on each island. It would seem that the characteristic habitat of megasoma is a swamp or marshy pond or bay." Quote from Baker, F.C. 1911, "The Lymnaeidae of North and Middle America, recent and fossil": Chicago Acad. Sci. Spec. Pub. 3 xvi, 539, 58 pl.

Two fossil fresh water gastropods (snails) from the middle Miocene Barstow Formation, Fossil Bone Basin, Mojave Desert, California.

Left to right. Far left and middle are two views of the same fossil fresh water gastropod (snail) from the middle Miocene Barstow Formation, Fossil Bone Basin, Mojave Desert, California. It's approximately 15 million years old, called scientifically Planorbula mojavensis. An image taken from a specific public domain document. Actual width of original specimen is 25 millimeters (.98 of an inch). Width of Planorbula mojavensis specimen at far right is 17 millimeters (.67 of an inch). Closest living relative of Planorbula mojavensis presently inhabits Louisiana and Georgia, north into Canada--"a species of swales or of small and stagnant bodies of water." Quote is from the specific public domain document from which the image came.

Three views of the same fossil fresh water gastropod (snail) from the middle Miocene Barstow Formation, Fossil Bone Basin, Mojave Desert, California. It's approximately 15 million years old, called scientifically Memetus microphalus. An image taken from a specific public domain document. Actual width of original specimen is 15 millimeters (.59 of an inch). Its closest living relative presently inhabits the Pacific Coast from British Columbia to southern California at high altitudes; "Memetus usually inhabits quiet or slow-moving shallow waters with abundant vegetation." Quote is from the specific public domain document from which the image came.

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