Newcomb's Snail - Taxonomy

Taxonomy

The scientific collection efforts of the United States Exploring Expedition of 1838 to 1842 obtained the first known specimens of Newcomb's snails. Historical documents indicate that the specimens were collected sometime between 25 October and 6 November 1840, at "Hanapēpē Falls," presumably what is now called Manuwaiopuna Falls, or possibly one of several other waterfalls located in the middle Hanapēpē watershed of southeast Kauaʻi. Individuals from this early collection made their way to the British Museum of Natural History and were used as the type specimens from which the species was later described in 1855.

As type locality is referred: "Heneta River, Kami, Sandwich Islands", which means Hanalei River, Kauai, Hawaii. English common name and also specific name is in honor of Dr. Wesley Newcomb, that collected them in Hawaii.

Erinna newcombi is one of four species of Lymnaeidae snails are native to Hawaii. Three of these species inhabit two or more of the eight main islands. The fourth species, Newcomb's snail, is restricted to the island of Kauaʻi.

A Japanese lymnaeid exhibits a very similar reduced shell shape, but a study of chromosome numbers suggests that Newcomb's snail's evolutionary ties lie with the rest of the Hawaiian lymnaeids, all of which are derived from North American ancestors. Therefore, it appears that parallel evolution of similar shell morphology occurred between these two distinct lineages of lymnaeid snails.

At the present time, no completely accepted nomenclature exists for the genera of Hawaiian lymnaeids, although each of these snail species, including Newcomb's snail, is recognized as a valid species. Bengt Hubendick (1952) did not believe the distinctive shell form (described bellow) and reduced structures of the nervous system of Newcomb's snail warranted a genus (second species of the genus Erinna is considered extinct). In fact, Hubendick included all Hawaiian lymnaeids in the genus Lymnaea. Joseph Paul Eldred Morrison (1968) contradicted Hubendick and argued the distinctive shell characters of Newcomb's snail supported the generic name Erinna. John B. Burch (1968), Charlotte M. Patterson and Burch (1978), Dwight Willard Taylor (1988), and Robert H. Cowie et al. (1995) all followed Morrison and referred to Newcomb's snail as Erinna newcombi, which is the currently accepted scientific name.