Faxonius immunis

Based on Crandall and De Grave (2017), the representatives of Orconectes form at least two distinct groups. The nominal group (the "cave Orconectes") form a monophyletic group that is more closely related to members of Cambarus, while the remaining "Orconectes" are more closely related to Barbicambarus, Creaserinus, and other species of Cambarus (Crandall and Fitzpatrick 1996, Fetzner 1996). As the type species of Orconectes, Orconectes inermis Cope, 1872, belongs to the cave-dwelling group, the genus is herein restricted to just those taxa. The surface-dwelling taxa now excluded from Orconectes sensu stricto are herein placed in the resurrected genus Faxonius Ortmann, 1905a, the oldest available name previously considered to be a synonym of Orconectes Cope, 1872.

This is a wide-ranging species that occurs from southern Quebec and New England westward across the upper Midwest to Wyoming and eastern Colorado and south to extreme northwestern Tennessee (Hobbs, 1989). It is widespread and faces no threats.

This is a wide-ranging species that occurs from southern Quebec and New England westward across the upper Midwest to Wyoming and eastern Colorado and the Dakotas and south to extreme northwestern Tennessee (Hobbs, 1989; Pflieger, 1996).

Although Hobbs (1989) listed Alabama, no recent specimens have been found there. In Kentucky, it occurs commonly across the western half in the lower Ohio, Green, Cumberland, and Tennessee River drainages and in several Mississippi River tributaries but is most common in the lower Green River drainage (Taylor and Schuster, 2004). In Missouri, it occurs exclusively in teh Prairie Faunal Region and on the flood plains of the Missouri and upper Mississippi Rivers (Pflieger, 1996). In Kansas, it occurs in northeastern Kansas in the eastern Kansas and Marais des Cygnes River basins (Ghedotti, 1998). Populations have recently been found in Colorado in the Colorado River (Rogers, 2005). In New England, where scattered (occasionally large) populations are known from every major drainage system except the eastern coastal drainage systems, occurrences are likely the result of early introductions (Smith, 2000). Occurrences in the Lower Monongahela drainage in Pennsylvania were reported to USGS as introductions. In Ohio, it occurs widely, but spottily in the Lake Erie basin in the northern and northwetern part of the state (Thoma and Jezerinac, 2000). It occurs statewide in Indiana with the greatest abundance in southwest Indiana (Simon et al., 2005). It also occurs in the northern portion Lake of the Woods, Ontario, Canada (Jansen et al., 2009) where it is considered invasive.

Is is unlikely that Orconectes immunis is being impacted by any major threats.