Lampsilis abrupta

USFWS (2018) reviews the taxonomic history of this species, as well as relationship to the highly similar L. higginsii, and recommends a comprehensive phylogenetic analysis of what some believe to be a species complex. Gordon (Gordon, pers. comm. to J. Cordeiro, 1993) beleived that Louisiana, Arkansas, and Missouri populations may represent an undescribed species.

The overall range of this once very widespread species has diminished by approximately 80%. Surviving populations generally inhabit small stretches of rivers and are typically isolated from others. Although currently known from more than two dozen localities, most are represented by very few, old individuals and likely have poor viability. Principal threats include structural hydrological alteration (damming and channelization), declining water quality (pollution and siltation), and invasive species.

Historically, this widespread mussel was known chiefly from several USA interior basins, including the Ohio, Mississippi, Tennessee, and Cumberland rivers (USFWS 1985).Populations (often rare and represented by few, if any, live individuals) have been documented from at least 25 river systems including the Flint River, Alabama; Limestone Creek, Alabama; Duck River; Holston River; French Broad River; Cumberland River; Clinch River; Obey River; Ohio River; Allegheny River; Elk River, West Virginia; Kanawha River, West Virginia; Scioto River; Muskingum River; White River, Indiana; Wabash River, Indiana and Illinois; Mississippi River, Illinois and Iowa; Illinois River; Ouachita River and Old River, Arkansas; Black River; Sac River, Missouri; and St. Francis River, Missouri (USFWS, 1985). 1990s data indicate that the species is extirpated from Pennsylvania (Bogan 1993), New York (Strayer and Jirka 1997), and Virginia, and possibly Indiana, Illinois, and Ohio (Watters 1995; Matthews and Moseley, 1990; Cummings and Mayer, 1997).

In 2018, the U.S. Fish and Wildlife Service recognized 29 extant stream populations, most of which were small to very small and limited to short river reaches (USFWS 2018). Because some of these are represented by only one or two individuals in the previous 30 years, number of occurrences is rated as B rather than BC. The status of pink muckets in each of the 29 streams is reviewed in USFWS (2018).

Matthews and Moseley (1990) reported 20 sites. In Alabama, it is rare in riverine reaches downstream of Wilson and Guntersville dams; a single gravid female was found in Bear Creek, Colbert County (Mirarchi et al. 2004, Williams et al. 2008). In Louisiana, Vidrine (1993) reported it from only Bayou Bartholemew. In Missouri, specimens have been recorded from the St. Francis River, the Sac River, and the mouth of the Bourbeuse River to the mouth of the Meramec River, with other populations (possibly historical) in the lower Big River, lower Meramec River, Little Black River, and lower Osage River (Oesch 1995). In Tennessee, this species has been found living in the tailwaters of several dams, and there is a localized relict population in the Cumberland River, Smith County, but all individuals were very old. It is nearly gone from the upper and middle stretches of the Tennessee River, although there was a stable population below Pickwick Landing Dam in Hardin County; populations in the Cumberland River are also localized, while occasional individuals can be found in several small to medium-sized tributaries of large rivers including the Holston, French Broad, and upper Clinch rivers (Parmalee and Bogan, 1998). In Ohio records exist in the Ohio River mainstem at a few sites bordering West Virginia (Watters et al., 2009) and in Greenup Dam pool in Ohio/Kentucky (Watters and Flaute, 2010). Tolin et al. (1987) reported occurrences in the upper free-flowing 3.5 miles of the Kanawha River and the mainstem of the Ohio River (at depth) at the West Virginia border. Taylor and Horn (1983) also included the Kanawha and Elk rivers in West Virginia. In Arkansas, populations are known from between river miles 50.5 and 161.5 of the Black River, the Ouachita River (Posey et al., 1996), White River (Gordon, 1982: upper White River; Christian, 1995), and 18 km of the Spring River (Harris et al., 1997; Harris and Gordon, 1987). In Kentucky, the species occurs sporadically in the lower Ohio River to the Licking River (Cicerello and Schuster, 2003).

Major known threat categories are modification of habitat (dams, dredging, and channelization), degradation of water quality (siltation and pollution), past overharvest by the commercial mussel industry, and the negative effect of invasive species (e.g., zebra mussel). Specifically these include alteration or destruction of stream habitat by impoundment for flood control, navigation, hydroelectric power, and recreation; siltation from strip mining, coal washing, dredging, farming, logging, and road construction; and pollution from municipal, industrial, and agricultural waste discharges (USFWS 1985).