Monographs of the Western North American Naturalist

Volume 2 Article 4

8-13-2004

Intermountain freshwater mollusks, USA (Margaritifera, Anodonta, Gonidea, Valvata, Ferrissia): geography, conservation, and fish management implications

Peter Hovingh [email protected]

Follow this and additional works at: https://scholarsarchive.byu.edu/mwnan

Recommended Citation Hovingh, Peter (2004) "Intermountain freshwater mollusks, USA (Margaritifera, Anodonta, Gonidea, Valvata, Ferrissia): geography, conservation, and fish management implications," Monographs of the Western North American Naturalist: Vol. 2 , Article 4. Available at: https://scholarsarchive.byu.edu/mwnan/vol2/iss1/4

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INTERMOUNTAIN FRESHWATER MOLLUSKS, USA (MARGARITIFERA, ANODONTA, GONIDEA, VALVATA, FERRISSIA): GEOGRAPHY, CONSERVATION, AND FISH MANAGEMENT IMPLICATIONS

Peter HovinghI

ABSTRACT.~Fieid collections at more than 2900 sites and the examination of many museum collections and litera­ ture allowed me to map the historical and current distribution of several freshwater molluscan faunal groups in the Intermountain region of the United States (Great Basin, Colorado River drainage basin, and upper Snake River sub­ basin). Historical and current records show that Margaritifera falcata, Anodonta californiensis, and Ferrissia rivularis have drainage-specific distributions, while Valoata utahensis has a specific drainage pattern, and V californica (new combination) has a dispersed pattern. Shell morphometric data of Valvilla and Ferrissia show extensive shell variation between and within populations. Current surveys show that these molluscan populations have been reduced since the colonization by European descendants over the last 1.50 years. l'vlargariiifera falcaia was found to be extirpated from eastern California, Kevada, and Utah and was common in only 1 stream. Anodonta californiensis populations of 10 or more individuals occurred in only 2 of 13 drainages, as well as in 1 isolated spring. Valvata californica was extirpated in 7 of 10 lakes. Ferrissia rivularis was velY rare in 6 of 12 drainages. Range declines among these fanna are thought to be related to alterations of habitat caused by grazing, irrigation, and urbanization, as well as the intensive management of sport fish in these waters.

Key words: mollusks, Intermountain ""Vest, distribution, conservation, fish management, Margaritifera, Anodonta, Gonidea, Valvata, Ferrissia.

The Intermountain region of the western that the molecular differentiation indicates United States includes the endorheic Great more complexity than species distribution Basin and its many subbasins; the Columbia­ maps reveal. Snake River basin, largely cutting westward Here I describe the taxonomic and distri­ across the Intermountain region; and the Col­ bution status of mussels (Margaritijera, Ano­ orado River basin, cutting southward across donta, and Gonidea) and gastropods (Valvata the high plateau region. The region is bounded and Ferrissia) in the Intermountain West. by California's Sierra N evadas on the west, the Cascade Range on the northwest, and the .\1ETIIODS AND .\1ATERIALS Continental Divide on the east (Fig. 1). Taylor (1970, 1985) documented the living and fossil FIELD COLLECTIONS.-Field collections con­ freshwater molluscan fauna in western North sisted of visually examining lentic and lotic America and proposed drainage affinities for habitats; benthic sampling with a food strainer; this fauna group. Fish have responded to the and hand collecting from logs, rocks, and complex hydrology with high levels of endem­ debris. .\1ore than 2300 sites within the Great ism at both the species and subspecies levels Basin were surveyed (Fig. 2A, Table 1). Some (Hubbs and .\1iller 1948, Smith 1978). The 587 sites were surveyed in the Colorado River hydrobiid gastropods include many endemic basin, with the Green River (302 sites) and the species, as well as those that have a more gen­ Virgin River tributaries (109 sites) most exten­ eral distribution (Hershler 1998). In contrast sively sUlveyed (Fig. 2B). Over 100 sites were to the differentiation of fish and hydrobiids, surveyed in the upper Snake River drainages amphibians have responded to this complex (not shown). system with little or no morphological differ­ Great Basin springs were selected from entiation (Hovingh 1997), although Green et al. LI00,000 USGS maps. Streams and lakes were (1996, 1997) and Bos and Sites (2001) suggest sampled at accessible sites £i'om roads and trails.

1721 S~c()lld A\'~lI11e, Salt Lake City, UT tH103.

109 110 WESTER'J NORTH AMERICAN NATURALIST [Volume 2

Fig. 1. Locations of aquatic sites named in the text. Springs are ahhreviated as follows: Toiyahe Springs (TS), Fish Springs (FS), and Clover Springs (CS). Lakes are not laheled hut are shown in solid hlack: Bear Lake on the Utah-Idaho horder; the Great Salt Lake in northwestern Utah; Utah Lake, which is drained hy the Jordan River; Sevier Lake, the terminus of the Sevier River; Fish Lake, laheled as Fish in southern Utah; Big Bear Lake, labeled as Big Bear in south­ ern California; Owens and \Valker Lakes as terminals to those drainages; Lake Tahoe on the Nevada-California horder and Pyramid Lake (terminal lake) in the Truckee drainage; Eagle Lake, northwest of Pyramid Lake in Califomia; and Malheur Lake and drainages in southeastern Oregon.

Site selection was primarily based on geogra­ for a thorough survey of rivers, but this was phical coverage, and attempts were made to ex­ not attempted. amine all aquatic habitats except high-gradient Initially only live mollusks were collected, streams. I specifically tried to examine histori­ but in later stages of the study, the living mus­ cal molluscan sites in the latter part of the sur­ sels were only noted, and valves alone were vey. The rarity of mussels indicates the need collected. Living Margaritifera falcata were 2004] l:\rTERYIOUNTAIN MOLLUSKS 111

120·

44·

36·

'r;!J ~ .,~. w I \ ~I

Fig. 2A. Location of surveyed sites within the Creat Basin (inset). 213. Location of surveyed sites within the Colorado River basin Gletween the Creat Basin and the Continental Divide (dashed line) in the inset ofA. Each dot represents 1 to 10 sites.

TABLE 1. Number of river sites surveyed in the Creat (ANSP), Barrick Museum in Las Vegas (UNLV), Basin drainages. Brigham Young University (BYU), California Drainage River sites Total sites Academy of Sciences (CAS), Chicago Acad­ BONNEVILLE BASIN emy of Sciences (CA), Field Museum of Nat­ Bear River 25 203 ural History (FMNH), Los Angeles County Weber River 7 101 Museum (LACM), Museum of Comparative Jordan-Provo Rivers 22 207 Zoology (MCZ), Ohio State University Museum Sevier River 1.5 216 (OSM), Santa Barbara Museum of Natural LAHONTAN BASIN Truckee River 20 52 History (SBMNH), Smithsonian Institution Carson River 14 36 (USNM), University of Colorado, Boulder Walker River 16 4,5 (UCM), University of Michigan Museum of Humboldt River 17 382 Zoology (UMMZ), and Utah Museum of Nat­ DEATH VALLEY BASIN ural History (UU). These museum collections Owens River 10 ,37 were examined during a 10-year period begin­ Mohave River 8 10 Anlargosa River 1 38 ning in 1990. The lots were examined drawer by drawer for geographical records of the Intermountain region. Selected lots were then examined in detail, and the species were com­ too rare to collect at alL In addition, in the pared. Appendix 1 lists the catalog numbers of later stages, shells were collected that may all specimens examined and collected for this represent specimens from Recent to Pliocene paper. deposits. Voucher specimens from this study MORPIIOylETRIC ANALYSES.-Morphometric have been deposited at the Utah Museum of analyses were performed on Valvata (shell Natural History in Salt Lake City. width or diameter and height) and Ferrissia MUSEUM COLLECTIONS.-Museum acronyms (length, width, and height) following Burch follow the designations of Leviton et aL (1985): (1989). The ratio of apex distance from the Academy of Natural Science in Philadelphia posterior to the total length was determined 112 WESTERN NORTH A:VIERICA.\! NATURALIST [Volume 2 with Ferrissia. Measurements were taken using Crossman 1973, Minckley et al. 1986), based an eyepiece with a 64-square grid calibrated on the necessity of salmonid fish for glochidia at 0.1 mm. Other structural characteristics survival. Margaritifera falcata distribution is noted in Valvata were the apex (visible or sup­ more geographically limited than the distribu­ pressed from a lateral view), the umbilicus tion of salmonid fish; it is found in drainages (narrow or wide with the umbilicus apex read­ from the Kern River in southern California to ily visible), whorl sutures (acute to obtuse), the coastal drainages of southeastern Alaska and the presence of collabral or axial striae and east from the northern Great Basin to the with riblets ranging from close together (;2:13 Columbia-Snake River basin and the upper per mm) to well developed (:59 per mm) on Missouri River (Burch 1975, Taylor 1981, 1988). the body whorl (Clarke 1973). Characteristics There are no specimens from the Colorado noted in Ferrissia included the vertical slope River basin, although this species was thought of the 2 lateral, the anterior, and posterior to exist in Arizona (Walker 1910). sides, and the shape ofthe peritreme. Within the Intermountain area, M. falcata FOSSIL OR LIVING STATUS.-I attempted to has been found in the Jordan, Weber, and determine if the specimens were alive at the Bear River drainages ofthe eastern Bonneville time of collection. Preservation of soft tissue Basin; in the Walker (fossil only; Call 1884), in alcohol was the best evidence of live collec­ Carson, and Truckee Rivers in the western tion. Ifall specimens in a given lot were white, Lahontan Basin; in the Humboldt River of the they were considered to be semifossils (Call northern Lahontan Basin; in the Alvord Basin 1884). As noted with the Bear Lake (Utah, of Nevada (fossil dated 7000 to 9000 BP in an Idaho) fauna, fossil radiocarbon-dated shells early American midden; Parmalee 1988); and (8000 BP) can appear fresh (Henderson 1931, in the Malheur Lake drainage of Oregon (Fig. Williams et al. 1962), and Oviatt (1987) found 3). Although Call (1884) mentioned semifossil "fresh-appearing, articulated Sphaerium shells" or post-Bonneville presence at numerous loca­ dated 23,000 BP in the Old River Bed of the tions in the Sevier Desert, neither his Table Sevier River drainage. Opercula in Valvata III ("Fossil Bonneville Mollusca") nor his Table suggested a recent living specimen. Ferrissia V ("Distribution of Freshwater Shells") lists were noted as fossils if their shells were any fossil or semifossil specimens from the greatly thickened and were of diminutive size Bonneville Basin. There are no specimens of (representing the uneroded apex). Literature Margaritifera from the Sevier River drainage, references are noted for studies relating to the Sevier Desert, or the western Bonneville paleogeography, although the specimens were Basin, contradicting Call's (1884) statement that often consumed for radiocarbon dating. they are "common throughout the Basin" (see also Roscoe 1963, 1964, Hunt 1981). RESULTS There is a possibility that 111. falcata was translocated by the movement of sport fish, Margaritifera falcata Gould 1850 such as rainbow trout from the Pacific Coast, Western Pearl Shell beginning in 1874 (Scott and Crossman 1973). TAXO.\!O:VIIC CO.\!SIDERATIO.\!S.-There are Rainbow trout arrived in Utah in 1883 (Sigler references of Margaritifera margaritifera 1953) and were found in Utah Lake and the occurring in the western United States (Call Provo River by 1894 (Heckmann et al. 1981). 1884, Walker 1910, Chamberlin and Jones The first trout hatchery in Utah was built in 1929, Henderson 1936a), but Taylor (1988) 1910, and by 1930 the Midway (Provo River found only 111. falcata in the western United drainage) and Kamas (Weber River drainage) States and Canada, based on the cardinal teeth hatcheries were built. To assess the possibility structure, and found an undescribed species of M. falcata introductions, 2 criteria were in central Idaho (drainage distribution un­ used: (1) museum specimens were collected known). I adopted Taylor's (1988) taxonomic before 1890 and (2) individual specimens >55 analysis, which provides geographical continu­ mm were assumed to be at least 15 years old. ity by drainage history. Based on these 2 criteria, specimens collected HISTOHICAL DISTRIBUTIO.\!.-The distribu­ between 1880 and 1890 near Salt Lake City, tion of 111. falcata is included within the range the Humboldt Rivel~ and the Truckee River of the native western salmonid fish (Scott and are considered to be native. However, there is 2004] INTEHMOUNTAIN MOLLUSKS 113 some uncertainty whether the specimens found Mussel valves reached a length of92 mm in in the Weber and Provo River drainages are the Truckee River (Murphy 1942) and 84 mm native; all are dated largely after fish hatchery in the Bear River (USNM 635195); both are construction. Specimens collected after con­ much smaller than the 150 mm size in the struction of the Kamas fish hatchery include Columbia River drainage (Roscoe and Redel­ those from Beaver Creek (the Weber River tri­ ings 1964, Vannote and Minshall 1982). The butary that passes the hatchery) in 1947 (FMNH Bear River population profile (USNM 635195: 111628, 179817), those from Kamas in 1939 N = 89; range, 40-84 mm; mode, 73 mm) sug­ (Woolstenhulme 1942), and those from the gests a younger mobile population (20 to 40 Kamas fish hatchery itselfin 1981 (OSM 52426). years) that could survive limited sediment With the exception of the specimen from East deposition, in contrast to the more stable and Canyon (UCM 10311) and the Beaver Creek immobile populations in large block boulder drainages, there is no record of M. falcata in reaches of the rivel~ which contain individuals the Weber River. The historical distribution may as old as 100 years (Vannote and Minshall 1982). have been confined to streams west of the CONSERVATION CONSIDERATIONS.-In the northern Wasatch Mountains and the Bear early 1940s the Truckee River contained an River in the Bonneville Basin and not in the estimated 20,000 M. falcata more than 40 mm Provo and Weber Rivers. Margaritifera arche­ in length in one 0.8-km stretch of river, and ological artifacts were identified from the Bear another population occurred 16 km upstream River and from Blacks Fork in the Green River (Murphy 1942). Six specimens were collected drainage (Warren 2000), suggesting, at least in in 1965 (CAS). I found only 1 shell fragment in the case of Blacks Fork, that early Americans this river. Margaritifera falcata was once com­ may have been responsible for transporting mon in the Salt Lake City region of the Bon­ some shells. neville Basin (Call 1884) but was rare in the PHESENT D1STHlBUTlON.-I found M. falcata Humboldt River in Nevada (Call 1884, Walker in the upper Snake River in Wyoming and 1916). In 1956 one hundred M. falcata were Idaho, the upper Bear River in Wyoming, and collected in the Bear River in Wyoming, while the Malheur Basin in Oregon. I did not find in 1998 only 5 live specimens (lengths: 43, 60, specimens at 155 sites in Utah, Nevada, and 65, 70, 83 mm) and 8 empty bivalve shells eastern California (Fig. 3). were found at this same site. A few thousand NATUHAL H1SToHY.-Known fish hosts for individuals per 140 m2 were observed in Wash­ the parasitic mussel glochidia were cutthroat ington State (Roscoe and Redelings 1964), sug­ trout fingerlings in Pole Creek (upper Snake gesting that the current numbers represent River, Wyoming) and introduced brown and depleted populations. rainbow trout in the Truckee River, but not 8 Many factors may have contributed to M. other fish species in those 2 drainages (Mur­ falcata decline. The spawning migrations of phy 1942, Banghmn 1951). In the Truckee River, Pyramid Lake's cutthroat trout were destroyed glochidia were released from mid-June to in 1905 when the Derby Dam was completed early July, when water temperatures increased on the Truckee River. In Utah's Jordan River from 10° to 15°C (Murphy 1942). Ofnote, both drainage, populations could have been extir­ cutthroat and rainbow trout spring migrations pated in 1948 by the destruction of Hot Springs and spawning occur at similar water tempera­ Lake, a 3.5-km2 lake that may once have con­ tures (Scott and Crossman 1973, Sigler et al. tained populations of cutthroat trout that bred 1983). Historically, young adult cutthroat trout in the streams around Salt Lake City. Cutthroat migrated up the Truckee River to Lake Tahoe trout native to Utah Lake were extirpated by in May, June (mostly, corresponding to glochidia 1936 (Radant and Sakaguchi 1980) by overfish­ release), and July, whereas the old adults had a ing and spawning habitat destruction, which fall migration that ended near Reno (Snyder terminated spawning migrations up the Provo 1917, La Rivers 1994). Glochidia remained on River (Heckmann et al. 1981). their host for 36 days (Murphy 1942). The Pole Otller factors contributing to the decline of Creek population is unique in that after deatll M. falcata include human alterations of Inter­ the calciferous shell disappears before the mountain rivers (Vannote and Minshall 1982), proteinaceous material. such as dredging and channeling rivers for 114 WESTERN NORTH AMERICAN NATURALIST [Volume 2

Fig. 3. Margaritiferafalcata distribution in the Intermountain region. Large dots represent the current distribution, small dots the historical distribution, diamond.s the fossil or semifossil distribution (1 site in northwestern Nevada). The historical locations in southwestern Idaho (4 sites) and the uppermost location on the Snake River (1 site) in Idaho were not examined in this study.

water diversion and flood control; dam con­ in Europe was correlated with an increased struction (16 hydroelectric power plants and nitrate concentration (Bauer 1988). 22 dams and reservoirs exist in the Bear River drainage basin); the use of river corridors as Anodonta californiensis Lea 1852 highway corridors; and declining water quality California Floater associated with reservoirs, urban areas, and agricultural practices (cattle grazing, irrigation TAXONOMIC CO"lSJDERATJO"ls,-Lea (1839) return flows). On this last point, it may be sig­ described 3 western Anodonta: A. nuttalliana (p. nificant that the mortality of M. margaritifera 77), A. wahlamatensis (p. 78), and A. oregonensis 2004] I)lTERMOU)lTAI)I .\10LLUSKS 115

(p. 80) from "Wahlamat, near the junction with (Howard 1996), but the Colorado River basin the Columbia river." This location is most and the Death Valley basin have been hydro­ likely the Willamette River. In describing A. logically separated for at least 4 million years californiensis from Rio Colorado, California, (Brown and Rosen 1995). Lea (1852) stated: "This species is more nearly Anodonta californiensis was found in 1934 allied, indeed it is closely allied to An. Nutt(d­ living in the Death Valley basin in the Mojave liana, which I described many years since, and River (LACM 104571, 104581). Pleistocene and which was brought by .\1r. Nuttall from Wahla­ Holocene fossils exist from the Owens Lake mat rivet; in Oregon." Henderson (1924, 1936a), drainage (SBMNH 10540; Firby et '11. 1997) Chamberlin and Jones (1929), and Taylor (1981, and the .\1 oj ave River drainage (Wells et a1. 1985) recognized these 4 species, whereas 1987) but not the Amargosa River drainage. others have consolidated these species to as In addition, A. californiensis has not pene­ few as 1 (Call 1884, Burch 1975, Clarke 1981). trated the interior basins of Nevada, although Anodonta dejecta Lewis 1875 in Arizona was many of these hydrologically isolated basins synonymized with A. californiensis (Bequaert contain native cyprinid fishes. Anodonta cali­ and .\1iller 1973). forniensis has not been noted in the upper For this paper I kept with the recent litera­ Snake River of Wyoming (Beetle 1989) but is ture of the Intermountain region, which may known downstream in Idaho. Pleistocene rec­ involve considerable conjecture, and identi­ ords occur in the Bonneville Basin (Eardley fied A. californiensis by its moderate fin. I found and Gvosdetsky 1960, Currey et a1. 1983, Ovi­ no high-fin Anodonta (A. nuttalliana or A. att et a1. 1999) and in tlle Lahontan Basin (Call wahlamatensis) in this study. Anodonta orego­ 1884, Benson et '11. 1992). nensis was identified in literature and museum The populations in the Little Colorado River collections in the early 1900s as existing in the drainage may have been transpOlted by hum,ms, Sevier and Humboldt Rivers. Now A. cali­ forniensis is identified in other literature and by stream caphtre, or, most unlikely; by glochid­ newer museum collections, with some muse­ parasitized fish migrating through the Grand ums leaving the western Anodonta identified Canyon. The Colorado River drainage popula­ only to the genus. If a synonymy in this group tion (Huntington Creek) in Utah suggests occurs, nomenclature priority will require re­ human transport (Figs. 4-5). This location con­ vising all collections, possibly following Call's sists of a 20-m-Iong fishing hole downstream (1884) view that these are A. nuttalliana. from a high-gradient stream and upstream HISTORICAL DISTRIBUTIO)I.-Western Ano­ fi'om the San Rafael River, a river ofhigh sedi­ donta extend from Alaska (A. beringiana .\1id­ ment, high alkalinity, and frequent flooding. dendorff 1851 and A. oregonensis) south to This population is totally isolated, except for .\1exico (A. californiensis and A. dejecta) and human intervention. These 2 examples are the as far east as Utah (A. nuttalliana, A. oregonen­ only Anodonta populations in the entire Colo­ sis, and A. californiensis), with A. wahlameten­ rado River drainage upstream from Las Vegas, sis found in 2 separate populations in Wash­ Nevada. ington and California (Taylor 1966, 1981, 1985, CURRENT DISTRIBUTIO)l.-1 found A. cali­ Burch 1975, Clarke 1981, Warren and Haring­ forniensis widely distributed as living speci­ ton 2000). mens and as shells in the Humboldt River Pleistocene A. californiensis occurred in Ari­ drainage (Lahontan Basin) in northern Nevada; zona and southern Nevada tributaries in the in the Bonneville Basin in Utah, Nevada, and lower Colorado River drainage (Bequaert and Wyoming; and in the .\1alheur and Warner .\1iller 1973, Quade et a1. 1995) and in the Basins in Oregon (Fig. 4) . Salton Trough, the latter basin representing an NATURAL HISTORY.-The fish host for this altered flow of the Colorado River. The Pleis­ species is listed as an introduced mosquito tocene uplift of the San Bernardino .\1ountains fish (Hoggarth 1992). Utah chub is the only and drainage transfer could have affected the fish in Redden Spring in western Utah (Work­ distribution of this species in southern Califor­ man et '11. 1979), making this fish a native host. nia (Taylor 1985). A paleodrainage outflow of The list of hosts for A. californiensis glochids the Colorado River during the late Miocene certainly will be expanded by further studies. has been located in the Los Angeles basin Adults were mature with 4 shell annuli age in 116 WESTER:'\! NORTH kvIERICA:'\! NATURALIST [Volume 2

Fig. 4. Anodonfa californiensis distribution in the Intermountain region. Large dots, small dots, and diamonds are marked as described in Figure 3. A triangle (l site) indicates specimens resulting from human transport. The .5 historical sites in the Snake River drainage of Idaho, Nevada, and Oregon and the 9 historical sites in Arizona were incompletely surveyed.

A. californiensis or with 8 shell annuli in A. Valley basin C'v:lojave lliver), Los Angeles Basin, wahlarnatensis (Heard 1975). and Central Valley in California (Bequaert and CO:'\!SERVATION CO:'\!SIDERATIO:'\!S.-It is dif­ Yliller 1973, Taylor 1981), areas in which in­ ficult to assess the status ofA. californiensis in tensive agricultural and urban development the Intermountain region largely because it is have occurred. A midden associated with a still widely distributed, but it is very scarce. It Chinese community in Tucson, Arizona, showed has most likely been extirpated from the Col­ Anodonta was common from 1880 to 1885 but orado lliver basin in Arizona and from the Death had died out by 1915 (Bequaert and Yliller 2004] I'JTERMOU'JTAT'J Y10LLUSKS 117

Fig. S. Distrihution ofConidea angulata (marked as in Fig. 3). The fossil record in southeastern Idaho and the historical sites in the Snake River drainages were not examined. P/fganodon grandis (square), Anodonta californiensis (triangle), and the current distrihution ofe. angulata (large dots on the Humholdt River in Nevada) resulted li'om human transport.

1973). Henderson (1931), citing Tanner's dredg­ for Barrick Gold Corporation, Elko, Nevada, ing efforts, noted that A. californiensis was the 1995). Y1cGuire (1995 report) found 3 live only living mollusk in Utah Lake. Utah Lake was mussels and 25 empty shells in a lO-hour greatly reduced by drought in 1933, and by 1977 search of Rock Creek (Humboldt River drain­ most fish in the lake were introduced species. age) in a 5-km stream survey. Three locations Anodonta californiensis was abundant in the in the current survey contained at least 6 A. Humboldt River near Carlin in 1912 and still californiensis, whereas the 12 other locations occurred in 1939 (Walker 1916, Jones 1940), contained lor, rarely, 2 specimens. but it was not found in this same region in Anodonta californiensis can live in reser­ recent surveys (0. Y1cGuire, report prepared voirs if the reservoirs are maintained at stable ll8 WESTER:\! NORTH AMERICA:\! NATURALIST [Volume 2

levels during a series of high-water years and Western Valvata can reach high numbers in these situations. TAXO:\!OMIC CO:\!SIDERATIONS.-The follow­ However, most reservoirs are actively m,maged ing prosobranch gastropods have been found with extensive drawdowns, and the mussels in western North America: Valuata hurneralis are extirpated during these low levels. Purges Say 1829 (see Say 1840), V lewisi Currier from reservoirs have dislocated and destroyed 1868, V rnergella Westerlund 1883, V sincera A. californiensis in the Bear River. The habitats Say 1824, V utahensis Call 1884, and V virens which A. californiensis now occupy are streams Tryon 1863. Only V utahensis has spiral angu­ and springs that (1) are not actively managed lations (Walker 1902, Heard in Burch 1989). for sport fish, (2) are in the higher reaches of Valvata lewisi has been suggested to be a syn­ drainage basins where better water quality onym of V sincera (Clarke 1973, Beetle 1989), occurs, and (3) are in regions with low human and Hannibal (1910) suggested that V lewisi population densities. and V sincera west of the Rocky Mountains would possibly be V hurneralis. Pyganodon grandis Say 1829 Valvata were compared with the following Giant Floater additional lots: V tricarinata Say 1817 from Wisconsin (UU 4108) and New York (UU 3670); This eastern species, also known as Ano­ V piscinalis .'1tiller 1774 from the Netherlands donta grandis and Anodonta corpulenta (see (UU 3(369); V hurneralis holotype from Mexico Hoeh 1990), was found in Arizona between (ANSP 58064); V drens from Clear Lake, Cal­ 1951 and 1969 (Fig. 5) as a result of human ifornia (UMMZ 143591; ANSP 371413 para­ transport via fish (Bequaert and Miller 1973, lectotype, 365358); V rnergella from Alaska Heard 1975). The species was still present in (UU 13037); and V sincera from Michigan upper Lake Mary in 2002 (this study). (MCZ 30759; FMNH ll4683, 104897, 105173; UMMZ 31651), Illinois (FMNH 76430 listed Gonidea angulata Lea 1839 as V hurneralis), and Great Slave Lake, North­ Western Ridge Mussel west Territory (UU 14237). DISTRIBUTIo:\!.-Gonidea angulata is found from southern British Columbia to the Los Valuata virens Tryon 1863 Angeles Basin in southern California, east to Emerald Valvata Idaho and northern Nevada (Henderson 1936a, Valvata virens is a distinctively globose spe­ Taylor 1981). A fossil found in Lake Thatcher cies, with a pyramid shape and an acute apex (Taylor 1985) is the only record in the Snake that is clearly visible from all lateral views. River drainage above Shoshone Falls. Taylor Some specimens have a worn apex, but the (1981) noted that G. angulata has probably been apex is still very conspicuous. It was found extirpated from the Central Valley to southern only near Watsonville and Clear Lake in Cali­ California by agricultural and urban develop­ fornia (Taylor 1981; Fig. 7). ments. I found G. angulata in abundance in the Humboldt River in the same area that con­ Valvata utahensis Call 1884 tained only Anodonta californiensis in 1912 Desert Valvata and 1939 (Walker 1916, Jones 1940; Fig. 5), Valuata utahensis is a polymorphic species suggesting recent transport by humans. The exhibiting a wide range of forms: (1) conspicu­ mobile G. angulata is well adapted to survive ously bicarinate (dorsal and ventral; V utahen­ in streams with high sediment deposits and sis morph horatii Baily and Baily 1951, see can reach high densities on gravel and stabi­ Heard in Burch 1989) in Bear Lake; (2) con­ lized sandbars (Vannote and ~1inshall 1982). spicuously dorsal carinated with ventral angu­ Small mussels are found downstream from the lations, (3) whorls with a flat, angular appear­ large adult population upstream of Carlin, ance, and (4) dorsal carina and angulation suggesting that the G. angulata population is absent, whorls rounded but with ventral angu­ expanding. It is not known what effect this lation. Specimens that lack such ventral angula­ introduction will have on the rare native A. tion would be considered globose V califarnica californiensis. (see below). 2004] INTER:vIOU:'\TTATN MOLLUSKS 119

Valvata hurneralis Say 1829 specimen contained a depressed apical whorl, Glossy Valvata distinguishing it from V virens. Hannibal (1910) suggested that V lewisi and Only 1 specimen, representing the holotype V sincera west of the Rocky Mountains might of V hurneralis, occurred in the collections. be V californica. The distinguishing feature of This shell was described as "subglobose, de­ V californica in this case is the lack of, or very pressed: spire convex, not prominent: whirls depressed, collabral striae. The Great Slave three and a half, with the shoulder depressed, Lake population had the same shape (Appen­ plane; wrinkled across, or rather with slightly dix 2) and similar body pigment as the Bluff raised lines: aperture appressed to the penulti­ Lake population, but the former had lamellate mate whirl, but not interrupted by it: urnbili­ "blade-like" striae, clearly visible at 13X (see cus rather large" (Say 1840). It was distinguished V sincera helicoidea Dall 1905 and V s. sin­ from V sincera by a planar surface near the cera Say 1824 in Clarke 1973). The type speci­ suture. No specimens from the western United men of V sincera is lost (Walker 1906), but the States matched this holotype, suggesting that populations of V sincera that were examined V hurneralis may be confIned to Ylexico. generally had prominent and thickened ribs and lamellate striae. A few individuals from Valvata califomica Pilsbry 1908, these lots had more depressed riblets, approach­ new combination ing the shell of V californica. The general shapes (globose to planar) of V sincera and V ''The shell is much more depressed than californica were similar when populations with Valvata hurneralis, the last whorl descending the same width-height ratio were compared. less; whorls convex below the suture, not flat­ The aperture of both V sincera and V califor­ tened there as V hurneralis is" (Pilsbry 1908). nica could be round, or the internal side could Appendix 2 shows a continuum between glo­ be oval. Valvata sincera in Colorado (Wu 1989) bose (widthlheight = 1.1) and depressed shells is considered by these analyses to be V cali­ (width/height = 1.9) of some lots of western fornica. One lot (FMNH 105173) consisted of Valvata. Shell shape is site specific and does specimens with depressed riblets, with apex not have any predictable geographic distribu­ totally depressed below the first whorl (differ­ tion. Furthermore, the Big Bear Lake, Califor­ ent from V californica), and with a dorsally flat nia, population is average (width/height = body whorl (2 individuals). The holotype V 1.5). I suggest that the basis for the subspecific hurneralis has the body whorl rounded, with description is not valid. Since the western dorsally flattened interior whorls. form does not display the flattened whorls of One population (Taylor Canyon, Owyhee­ the V hurneralis holotype, I recommend the Snake River drainage, Nevada) differed from following changes in the name: Valvata califor­ V californica by its small size (2.6 mm width), nica Pilsbry 1908, new combination (glossy its totally black body, and its having fewer valvata); type locality, Big Bear Lake, Califor­ than 3 whorls. Its planar shape (width/heigth nia; synonyms (only in the United States and = 1.6) and lack of collabral striae were similar Canada), V hurneralis, V hurneralis califomica. to V californica. To prevent confusion hereafter, I will refer to DrSTRIBUTION.-Valvata californica is a this western United States Valvata as V cali­ western species (Fig. 6) with unknown north­ fornica since there is no basis for the sub­ ern or eastern boundaries (Taylor 1981) or species taxonomy and its shell is structurally southern boundaries in Ylexico. This species different from V hurneralis. occupies the Colorado River, the upper Rio The globose form of V californica (width/ Grande, the Columbia-Snake River, the Cali­ height = 1.1-1.2) occurs with V utahensis, fornia Pacific Coast drainages, and the Great and it may be conspecific with V utahensis. Basin (Fig. 6). Living V utahensis are known Valvata californica shell sculptures were smooth only from the Snake River drainage (Fig. 7), (striae obsolete) or with fine collabral striae or and the species is listed as endangered in the depressed riblets close together (;:d3 mm on United States. Valvata utahensis have been the body whorl; Clarke 1973). The Gerlach found in Idaho and Utah (Taylor 1985). Val­ population (UMMZ 237249) was exceptional, vata virens have been reported from 2 loca­ containing 10-12 collabral striae' mm-l . This tions in California (Taylor 1981; Fig. 7). 120 WESTER:\, NORTH AMERICA:\' NATURALIST [Volume 2

Fig. 6. Valvata californica distribution (marked as in Fig. 3). Historical locations in SOlithem Colorado, Arizona, and eastern Oregon were not exanlined.

Fossil V califomica are widely distributed (Eardley and Gvosdetsky 1960), and the ranges in western North America from the Miocene of V utahensis and V californica contracted and Pliocene, with Pleistocene records often during the Holocene. The fossil shells of V indistinguishable from shells of very recent and utahensis (UU 14037) are the first records living specimens (Eardley ,md Gvosdetsh)' 1960, from the Humboldt River, altering the distri­ Trimble and Carr 1961, Williams et at. 1962, bution pattern shown by Taylor (1985). Fossil Roscoe 1963, Taylor 1985, Quade 1986, Oviatt shells of V utahensis and V califomica (dated et at. 1987, Taylor and Bright 1987, Quade and 7000 BP) were found at an archeological site Pratt 1989, Quade et at. 1995, Bourchard et at. in northern YIills Valley in the Sevier River 1998). These studies show that V califomica drainage (T. Sharp and SWCA Environmental preceded V utahensis in the Bonneville Basin Consultants, personal communication, 2003), 2004] I"1TERYIOUNTAIN YlOLLUSKS 121

Fig. 7. Distribution of Va/vllia utahensis (marked as in Fig. 3) with the globose forms of V ca/ifomica shown as trian­ gles. Historical locations ofV virens in California are shown as squares. expanding the range of V utahensis in the suggest that dispersal of these species has not Bonneville Basin (not shown in Figs. 6-7). Other occurred during the Quaternary (Taylor and fossil Valvata species were found in western Bright 1987, Hovingh 1993). Valvata califor­ North America (Yen 1946, Taylor 1966, 1985, nica is found in glacier-associated drumlin Bequaert and Yliller 1973, Good 1987). ponds in the Wasatch Plateau (central Utah) and NATURAL IIISTORY.-Valvata occupy habitats northwest of Pinedale, Wyoming. These habi­ ranging from large lakes to small ponds, tats f"i-eeze solid in winter, are isolated from marshes, streams, and springs. The limited each other, and have no drainage. distribution of V virens (1 lake and 1 pond; Four isolated spring complexes in the study Taylor 1981) and V utahensis, along with the area (Fish Springs in Utah and Clover, Tonapah, dispersed distribution of V californica, would and Taylor Canyon in Nevada) contained V 122 WESTER"! NORTH A\1ERTCA"! NATURALIST [Volume 2 califarnica, whereas the hydrobiid gastropods F fragilis Tryon 1863 (with forms hendersoni, Pyrgulapsis gibba Hershler 1995 and P kalab­ shimekii, and isabellae), F parallelus Haldeman ensis Taylor 1987 are widely distributed in many 1841, F rivularis Say 1817, F walkeri Pilsbry springs and basins (Hershler 1998). Both Val­ and Ferriss 1906, and F mcneilli Walker 1925 vata and Pyrgulapsis occupy similar habitats (Basch 1963). In the eastern United States and and were captured at the same time in Fish Canada, F parallelus, F fragilis, and F walkeri Springs, whereas Valvata in the Tonapah Basin are identified as living in standing or slow­ occupied the spring head while Pyrgulopsis moving waters, while F rivularis and F mcneilli occupied the outflows. Valvata californica and (the latter found only in Alabama) are living in V utahensis coexisted in Utah and Bear Lakes flowing water (Basch 1963, Clarke 1973). and in Mills Valley. Valvata califarnica and V Basch (1963) noted much confusion in Fer­ virens coexisted in Clear Lake, but the extent rissia taxonomy, and museum collections reflect ofhabitat overlap is unknown. this confusion when F fragilis and F rivularis CO"!SERVATIO"! CO"!SJDERATJONS.-Assess­ have been cataloged from tlle same locations: ment of the status of Valvata in the Inter­ Lily Lake, Nevada County, California (CAS mountain region requires separation of shells 28161, 52108; SB,\1NH 117947); Utah Lake, from palaeo-populations and recent living Utah (MCZ 4578, 243275; UC,\1 7410; ANSP populations. Valvata utahensis was extirpated 144620; U,\1MZ 219474); Chiricahua Moun­ from Utah Lake; Call (1884) was the only per­ tains, Arizona (CAS 21093, 52105); and Sabino son to collect shells of this species with oper­ Canyon, Arizona (ANSP 115256-59, 328339; cula (Chamberlin and Jones 1929). From 1903 F,\1NH 58051, 64331). Wu (1989) recorded F to 1956 Valvata californica from Big Bear Lake rivularis and F walkeri in the same Yampa in California was collected in abundance as River sites in Colorado. Species diversity of shells with opercula, but in 1995 no shells the western Ferrissia may account for the above were found. In 1929 Fish Lake in Utah con­ taxonomic confusion. tained V californica (Chamberlin and Berry Intermountain collections were compared 1930), but it is absent there today. Valvata virens with type specimens ofFrivularis ANSP 21982, was extirpated in California (Taylor 1981). Both F fragilis ANSP 22011, F parallelus ANSP Big Bear Lake, California (Automobile Club of 21996, and F walkeri ANSP 87479. In addi­ Southern California 1928), and Fish Lake, Utah, tion, comparisons were made with F,\1NH have the same physical appearance today as in 64331 (Arizona), UU 11697 (Ohio), UC,\127178, the early 1930s, but both are currently managed 29943, 29952 (Colorado), UU 14239 (Queen for revenue-enhancing, nonnative sport fish and Charlotte Islands, B.C.), UU 10114 (Australia), water supplies. Fish in Big Bear Lake were and Ancylusfluviatilus Milller 1774 from Bel­ chemically extirpated in the 1960s, and pump­ gium (UU 12218) and England (UU 3861). kinseed sunflsh were introduced ('\1. Giusti, There were many variations in shape of the California Fish and Game communications, individual shells examined in this study. The 1999). Sunfish are predators of mollusks (Scott peritreme varied from near parallel to straight and Crossman 1973, Carlander 1977, Stein et on the right side and oval on the left side, to a1. 1984). Two Colorado lakes formerly con­ oval on both sides, to greatly expanded in the taining Valvata are now managed for sport fish, anterim; and from narrow to wide. The lateral including introduced crayfish. Valvata califar­ sides varied from acute concave on both sides nica co-occur with native fish in the Fish (3 Bear River specimens, U,\1MZ) to straight Springs, Clover, and Tonapah Basins. They have on both sides, to straight on the left side and disappeared in waters that are managed for concave on the right side, to convex on the left nonnative sport flsh, although they occurred side and concave on the right side. The mor­ in lakes (Utah, Fish, and Clear Lakes) with phometric range did not change much, and native fish communities. the sample means were within the standard deviation of most lots (Appendix 3). Shells were depressed (height/length = 0.32) in sam­ Ferrissia rivularis Say 1817 ples from Utah Lake (UU 13986), the San Creeping Ancylid Pedro River (UU 14230), and Queen Charlotte TAXONO\!IC CONSJDERATloNs.-Ferrissia is Islands (UU 14239); these samples were col­ a complex of freshwater limpets consisting of lected from plants. Populations from Sabina 2004] INTEWvlOUNTAIN YlOLLUSKS 123

Canyon (FMNH 64331) and the San Pedro Fork, New Fork River, and Yampa River; the River (UU 14230) had an apex-length ratio < Colorado River drainage in the Gunnison River 0.3 and distinctly to the f~lr right of center, (Colorado) and in the Gila River (Arizona). I characteristics suggesting F walkeri except for did not find F rivularis in the Walker, Carson, their lotic habitat. No populations contained or Quinn Rivers (Lahontan Basin); the Ylono the apex in midline, and only the San Pedro Basin; the hydrologically isolated interior basins population had a width-length ratio < 0.55, thus of Nevada; the Death Valley drainage; Deep excluding F parallelus. All populations had a Creek, Thousand Springs Creek, the Weber length> 3.5 mm except the Gila River popu­ River, or the Sevier River (Bonneville Basin); or lations, thus excluding F fragilis. in the Henrys Fork, White River, or Duchesne I consider all Intermountain ancylids to be River (Green River drainage). F rivularis, with shells having diverse struc­ NATUHAL HISTORY.-Ferrissia are hermaph­ tural features, as noted by Basch (1963; roditic and may be aphallate with self-fertiliza­ Appendix 3). The exception may be the Gila tion or parthenogenesis (Basch 1963). Eight River populations that meet the criteria of F eggs are typically produced per adult per year walkeri. Further studies of the Gila River may (Burky 1971), and in F parallelus, 12 egg cap­ determine if 2 populations there are site spe­ sules with 1 to 3 eggs each are typical (Clarke cific or drainage specific. All Intermountain 1973). Life expectancy is 2 summers at the Ferrissia were found in lotic habitats except most (Russell-Hunter 1978). There is much in­ the Utah Lake population. However, habitat terpopulation variation with both genetic com­ criteria for ancylid identification may be taxo­ ponents (shell chemistry and peritreme shape) nomically perilous, as aquatic habitats are more and environmental components (shell steep­ diverse than just streams and lakes. Lakes may ness; Russell-Hunter 1978, Russell-Hunter et have high turnover ofvolume related to stream a!. 1981). The interpopulation variation may input, and these habitats may be comparable be attributed to hermaphroditic or self-fertil­ to a pool in a stream drainage. Also, anyclids ization life histories and to passive dispersal occurring at the interface of substrate could (Russell-Hunter 1978, Russell-Hunter et a!. have similar habitats in flowing water and the 1981). wave zone in lakes. Ferrissia rivularis is found in habitats rang­ DISTHIBUTION.-Ferrissia fragilis and F ing from eutrophic to oligotrophic, low to high parallelus are found in western North America calcium concentration, and low to high min­ (Basch 1963, Clarke 1981, Taylor 1981, Burch eral content (Russell-Hunter et a!. 1981, Keat­ 1989, Wu 1989). Ferrissia walkeri is listed for ing and Prezant 1998). The occasional pres­ 3 widely disjunct populations: Michigan, ence of F rivularis in lakes and ponds may be Arkansas, and the southern tip of Baja Califor­ explained by the nature of the pond (a slow, nia, Ylexico (Basch 1963). Ferrissia rivularis is inflowing stream), by a chance invasion from a found throughout most of the United States riverine Pleistocene refugium (Utah Lake), or and in Canada (Clarke 1981, Burch 1989). Fer­ by adaptation to a new environment (such as a rissia is transported by humans via ornamental reservoir). In general, museum records of Fer­ water lilies and other aquatic plants (Hender­ rissia are sparse, most likely because plant son 1935b, Bequaert and Miller 1973). stems or the undersides of rocks were not ex­ Figure 8 shows the historical and current amined in historical surveys. locations for F rivularis. I found F rivularis in CONSEHVATION CONSIDERATIoNs.-Dams Silver Lake and Klamath basins (Oregon); the have caused a "precipitous decline" in river Lahontan Basin (California and Nevada) in the mollusk species (Basch 1963), including Truckee ,md Humboldt Rivers (except the Reese limpets. Ylanagement of streams for known River); the Bonneville Basin (Utah, Idaho, limpet predators, such as brown trout (Basch Wyoming, Nevada) in the Snake Valley, the 1963), may explain the current spotty distribu­ Provo River, Utah Lake, and Bear River; the tion of Ferrissia. Streams in the Intermountain Snake River drainage (Idaho) in Salmon Falls region have also been dredged to constrain Creek and in the Raft River (draining into the flood flows, and many have been diverted for Snake River respectively below and above the ilTigation. Ferrissia were historically more abun­ barrier Shoshone Falls); the Green River drain­ dant, according to records from the Weber age (Wyoming, Utah, Colorado) in the Blacks and Bear Rivers in the Bonneville Basin and 124 WESTER:'\! NORTH kvIERICA:'\! NATURALIST [Volume 2

Fig. 8. Ferrissia rivularis distrihution (marked as in Fig. 3). Fossil locations in southern Nevada, western Utah, and Arizona. Snake River historical sites were not surveyed in this study.

from Bloody Canyon in the Mono Lake basin, that contained limpets at many locations and California. Trout streams (all containing intro­ in the tributaries. duced trout) include the Provo, Weber; Bear, Blacks Fork, Truckee, and Bloody Canyon DISCUSSION streams and are now largely unoccupied by limpets. An exception is the New Fork River If aquatic ecosystems and their native spe­ (upper Green River drainage, Wyoming), where cies are to be preserved and managed, it is the gravel-cobble substrates contain up to a important to have well-corroborated species dozen specimens on a lO-cm rock. Two streams boundary, distribution, and population trends. with few trout (the middle Yampa and Hum­ Unfortunately, such information is not readily boldt River drainages) were the only streams available for invertebrates in the western United 2004] I:\'TERMOU"ITAT"I MOLLUSKS 125

States. The following discussion is divided into Within rivers, major waterfalls act as barriers. the general problems oftaxonomy, distribution, The Shoshone Falls separate the upper Snake and natural history as they relate to declining River with its fish affinities to the Bonneville mollusk species and their conservation. Basin from the lower Snake River with its affinities to the Columbia River. This waterfall Taxonomy and Distribution barrier separates 21 species of fish (Smith Species distributions may often define the 1978) and 2 species of amphibians (Hovingh species itself. With modern tools such as mole­ 1997). Species that occur above and below this cular genetic analysis, new concepts of the barrier, such as M. falcata, A. californiensis, and species and species redefinitions are occurring. F rivularis, may be candidates for cryptic evo­ The populations of gastropod Lymnaea stag­ lution. Another barrier type in rivers is rep­ nalis Linnaeus 1758, separated by the Alps in resented by the Grand Canyon in Arizona. The Europe, were differentiated at the molecular lower Colorado, including the Gila and Virgin level without morphological variation, suggest­ Rivers, appears to be isolated from the upper ing geographical isolation (Remigio and Blair Colorado River, as demonstrated by disjunct 1997a, 1997b). Three Stagnicola species with populations of Ferrissia and Anodonta. Lower distinctive shell shapes in the post-glacial Colorado River aquatic fauna may be more Great Lakes region were genetically indistin­ closely associated with the Salton Sea, Death guishable (Remigio and Blair 1997a, 1997b), Valley, and the Los Angeles Basins. suggesting a recent post-glacial occupation of The widespread distribution of a species a new habitat with local adaptations. These may indicate evolutionary stasis. Valvata cali­ evolutionary processes may be occurring in fornica has a wide distribution in the Inter­ the Intermountain region. mountain region in space and time, preceding The interbasin distribution of aquatic mol­ the formation ofthe Great Basin in the Miocene, lusks may have been very selective through the Wasatch and Sierra Nevada ranges in the differences in fish distribution, drainage history, Pliocene, and the current Colorado River. This and species-specific geographical barriers. The species may represent an evolutionary stasis Continental Divide is a major aquatic barrier. over 5 to 7 million years (Brett and Baird 1995). The distribution of Margaritifera falcata and Until more is known about such widespread cutthroat trout in the upper Missouri Rivers was a natural breach in the barrier across the species, conservation efforts should maintain divide. Major river drainage boundaries are populations at the subbasin drainage level to also selective barriers. Neither M. falcata nor preserve the full taxonomic variation. Anodonta californiensis moved between the Natural History and upper Snake River and the upper Green River, Conservation although cutthroat trout have migrated between these drainages (Hansen 1985, Taylor 1985). .vlollusk fecundity is extremely variable as a However, the gastropods Valvata californica, life history strategy. Some species live for 10 Fluminicola coloradoensis, Ferrissia rivularis, to 100 years and produce thousands of glochids and Stagnicola hinckleyi occur both in the upper annually that attach to fish, whereas Ferrissia Green River and upper Snake River drainages, lifetime reproductive output may be only a indicating a past breach in this barrier. dozen offspring. However, glochid attachment Large Pleistocene lakes were as much a to fish does not necessarily ensure survival if barrier as drainage divides. Fluminicola colo­ few fish are present and only a few glochids radoensis, Ferrissia rivularis, and M. falcata metamorphose. Hermaphroditic reproduction occur in the Great Salt Lake drainages but not and self-fertilization can enhance reproductive in the Sevier River drainage. These drainages output, and this mode occurs in Valvata, in were tributaries of Pleistocene Lake Bonne­ Ferrissia, in a small percentage of Margari­ ville. Similar large lake barTiers isolated amphib­ tifera falcata, in Anodonta californiensis, and in ians (Hovingh 1997) and crayfish (Johnson Gonidea angulata (Basch 1963, van der Schalie 1986). Large lakes may serve as barriers by 1970, Heard 1970, 1975 in Burch 1989). Low creating highly variable shorelines with high­ reproductive rates with self-fertilization may energy wave action or through limited migra­ explain the persistence of some small popula­ tion after the lake desiccated. tions in the Intermountain region. 126 WESTER:-J NORTH A\1ERICA:-J NATURALIST [Volume 2

Grazing, irrigation, and urbanization through Big Bear, and Tahoe Lakes in California (Mur­ water diversion, channelization, and dams (Raw­ phy 1951, Heckmann et a1. 1981, La Rivers lings and Nee11989, Ward 1998), all leading to 1994, Frantz and Cordone 1996, this study). deterioration of aquatic habitat, are usually the Introduced fish have affected other fish (La reasons listed for the decline of bivalve mol­ Rivers 1994, Walser et a1. 1999), amphibians lusks (Bogan 1993, Williams et a1. 1993, Watters (Bradford et a1. 1993, 1998), and macroinverte­ 1996, Vaughn and Taylor 1999). The current brates (Lamontagne and Schindler 1994, Frantz locations of molluscan fauna in the Intermoun­ and Cordone 1996, Parker et a1. 1996, Bradford tain region are in springs, streams, and ponds et a1. 1998, Carlisle and Hawkins 1998), in con­ near headwaters in primarily rural landscapes, trast to aquatic systems in which macroinver­ suggesting that water quality is a major con­ tebrates coevolved with fish (Hershey 1990, straint today. Merrick et a1. 1992, Strayer 1999). In addition Largely overlooked in the decline ofaquatic to introductions of fish, fish food (nonnative fauna are manipulations of fish communities. shrimp and crayfish) is also introduced. Such Fish are hosts for mussel glochidia, introduced introductions affect the aquatic system in dif­ fish may prey on mollusks (Bogan 1993, Strayer ferent ways (Johnson 1986, Frantz and Car­ 1999), and dams can limit fish distribution done 1996). (Watters 1996, Vaughn and Taylor 1999). Inter­ The "top-down" habitat management is mountain streams have been extensively man­ rather far reaching when one examines the aged for nonnative trout fisheries for more potential effects on aquatic fauna by intro­ than 50 years and are no longer a suitable habi­ duced fish. Most stocking programs (1) had tat for Margaritifera falcata, even if the intro­ inadequate habitat studies, including inverte­ duced rainbow trout supports the glochidia brate monitoring and surveying, (2) did not stage of mussel development. Sport fish man­ consider whether the lake habitats are man­ agement has not substituted for the loss of aged by the Wilderness Act and national park trout migration or the native trout. designation for biodiversity and ecosystem cri­ Sport fish management is a "top-down" teria (most lakes in wilderness areas and strategy that disrupts natural fish communities, national parks were stocked with fish, and the food webs (Moyle 1976, Bisson 1978, McGinnis stocking continues), (3) failed to distinguish 1984, Northcote 1988, Power 1990, Dunham introduced species from native species, and et a1. 1999, Walser et a1. 1999), and mollusks (4) failed to determine whether the habitats (Basch 1963, Carlander 1969, Scott and Cross­ stocked have self-sustaining native popula­ man 1973). More than 9 species of fish have tions (Bahls 1992). Long-term sustained yield, been stocked in Fish Lake (Utah) since 1906 ecosystem management, and native inverte­ (Sigler 1953). Since the 1960s the annual stock­ brate biodiversity typically are not goals of flsh­ ing rate there has been more than 20,000 kg of stocking programs. catchable rainbow trout and 120,000 finger­ ling trout (Utah Division ofWildlife Resources, CO:-JCLUSIO:-JS personnal communication, 1999). Studies on the diet of the trout showed that gastropods 1. The bivalve mussels Margaritifera falcata were "an appreciable item" (Hildebrand and and Anodonta californiensis have greatly dimin­ Towers 1927, Sigler 1953). A study by Cham­ ished numbers compared to historical reports. berlin and Berry (1930) noted the abundance Margaritifera has been extirpated from eastern ofgastropods in Fish Lake: Lymnaeidae (2 spe­ California, Nevada, and Utah and was com­ cies), Planorbidae (3 species), the endemic Phys­ mon (;;,10 specimens) in only 2 of 9 streams. idae Physella microstriata, and Valvata califor­ Anodonta was common (;;;:10 specimens) in nica (Chamberlin and Berry 1930). By 1989 only 2 of 13 streams. These reduced numbers there were Lymnaeidae (2 species, 1 of which can be attributed to sport fish management, as was introduced) and Physidae (1 species was well as impacts from agricultural and urban introduced). Deep lake dredging did not reveal development. any living mollusks (A.H. Clarke, report pre­ 2. Valvata californica populations were ex­ pared for U.S. Fish and Wildlife Service, 1991). terminated in lakes dedicated to sport fish in­ The extirpation of mollusks also occurred in troductions. Valvata californica survived in Navajo and Utah Lakes in Utah and in Clear, habitats with native fish or in fishless habitats 2004] I:-JTER\fOUNTAIN YlOLLUSKS 127 and was found to be common in 3 lakes but documents. I greatly appreciated the opportu­ extirpated in 7 lakes. nity to examine specimens from the many 3. Ferrissia rivularis was confined to spe­ museums. I thank Kirsten Yl. Kempe for the cific drainages, being most abundant in the technical improvements in the manuscript and Humboldt River in Nevada and the Yampa D.L. Gustafson for use of the illustration on River in Colorado. Both systems had lower the reprint covers. sport fishery use. Half of the historically re­ corded streams contained a rare specimen (1 LITERATURE CITED or 2) or no specimens at all. 4. Taxonomic issues include species defini­ ACTO\IOnILE CLCB OF SOCTIIERN CALIFORNIA. 1928. Map showing automobile routes from the Orange Belt tion. Anodonta californiensis is the only Ano­ cities to the San Bernardino mountain resorts. donta living in the Intermountain region, where BAIILS, p. 1992. The status of fish populations and man­ 4 species or morphs had formerly been listed. agement of high mountain lakes in the western United States. Korthwest Science 66:183-193. Valvata califarnica has a highly variable shell BAILY, J,L. 1950. Some preliminary notes on the distribu­ shape, from globose to planar across its distri­ tion of Mollusca in the lakes of the western states. butional range, suggesting no support for the Kautilus 63:73-78. subspecies V hurneralis califarnica classifica­ BAILY, J,L., A"D R.r. BAILY. 19.51. Further observations on the Mollusca of the relict lakes in the Great Basin. tion, and does not have planar upper whorls Kautilus 65:46-53. different from V hurneralis. The taxonomy of BA"GIIAM, R.Y 1951. Parasites of fish in the upper Snake Ferrissia rivularis and F fragilis in museum River drainage and in Yellowstone Lake, Wyoming. records is confused, but only 1 species occurs Zoologica: New York Zoological Society 36:213-217. BASCII, PF 1963. A review of the recent freshwater limpet through most ofthe Intermountain region, with snails of Korth America (Mollusca: Pulmonata). Bul­ a possible 2nd species (F walkeri) in Arizona. letin of the Museum of Comparative Zoology 129: 5. The distribution of these molluscan fauna 401-461. is unpredictable but may be tied to events BACER, G. 1988. Threats of the freshwater pearl mussel in Central Europe. Biological Conservation 4.5:239-25:3. during and since the Yliocene. Each taxon has BEETLE, D.E. 1989. Checklist of recent Mollusca ofWyo­ its own aquatic intra- and interbasin barriers, ming, U.S.A. Great Basin Kahlralist 49:637-645. and large Pleistocene lakes were, in part, a BENSO", L., D. CURREY, Y. LAO, AND S. HOSTETLER. 1992. Lake-size variation in the Lahontan and Bonneville barrier to species dispersal. Basins between 13,000 and 9000 HC yr B. P Palaeo­ 6. The "top-down" manipulations of fish geography, Palaeoclimatology, Palaeoecolo!,'Y 95:19-32. communities by fish stocking may have had a BEQCAERT, J,C., A"D vVB. MILLER. 1973. The mollusks of greater effect on molluscan distribution than the arid Southwest with an Arizona check list. Uni­ versity ofArizona Press, Tucson. urbanization and agricultural development. BISSO", PA. 1978. Diel food selection by 2 sizes of rain­ 7. The negative impacts of sport fish manip­ bow trout (SaZ,no gaairdneri) in an experimental ulations on biodiversity and ecosystem cannot stream. Journal Fisheries Research Board Canada 35: be measured because of the frequency of these 971-975. BOGA;>,', A.E. 1993. Freshwater bivalve extinctions (Mol­ manipulations on most aquatic systems for lusca: Unionoida): a search for causes. American more than 50 years. Zoologist 33:599-609. Bos, D.H., A"D J,w. SITES. 2001. Phylogeography and con­ servation genetics of the Columbia spotted frog ACKNOWLEDGMENTS (Raila luteivelltris; Amphibia, Ranidae). Molecular Ecology 10:1499-1.513. I thank Mark Nelson, Patti Spindler, and BOURCIIARD, D.P, D.S. KAUFMA", A. HOCIIBERG, AND J, Peter Bradley for the opportunity to examine QL\DE. 1998. Quaternary history of tbe Thatcher Basin, Idaho, reconstructed from the 87S r/ se; Sr and specimens from their collections, Ylark Ports amino acid composition oflacustrine fossils, implica­ for sharing the Taylor Canyon Valvata site, tions for the diversion of the Bear River into Bonne­ Daniel YlcGuire for sharing his reports, and ville Basin. Palaeogeography, Palaeoclimatology, Janke Kolff and Heidi Bloomfield for curator­ Palaeoecology 141:95-114. BRADFORD, D.F, S.D. COOPER, T.M. JE"KI"S, JR., K. KRATZ, ial assistance. I thank Jack Sites, Dennis Shio­ O. SAR"ELLO, AND A.D. BROWN. 1998. Influences of zawa, Vicky Yleretsky, and 3 anonymous re­ natural acidity and introduced fish on faunal assem­ viewers for improving the manuscript. I also blages in California alpine lakes. Canadian Journal of thank the Nevada Division of Wildlife for Fisheries and Aquatic Science 55:2478-2491. BRADFORD, D.F, F. TARATABAI, A"iD D.M. GRABER. 1993. granting collecting permits and Robert Hersh­ Isolation of remaining populations of the native frog, ler for making available most of the historical Raila lIlucosa, by introduced fishes in Sequoia and 128 WESTER"! NORTH A'vlERICA"! NATURALIST [Volume 2

Kings Canyon Kational Parks, California. Conserva­ FRANTZ, Te., AI'\D A.J. COROOI'\E. 1996. Observations on tion Biolol,,), 7:882-888. the macrobenthos of Lake Tahoe, California-Kevada. BRETT, C.E., AI'\D G.e. BAIRD. 199.5. Coordinated stasis Califomia Fish and Game 82:1-41. and evolutionmy ecology ofSilurian to Middle Devon­ GOOD, S.e. 1987. Mollusc-based interpretations of lacus­ ian faunas in the Appalachian Basin. Pages 28.5-31.5 trine paleoenvironments of the Sheep Pass Forma­ in D.H. Erwin and R.L. Anstey, editors, Kew tion (Late Cretaceous to Eocene) of east-central approaches to speciation in the fossil record. Colum­ !\:evada. Palaios 2:467-478. bia University Press, KY. GREEI'\, D.M., H. KAISER, TE SIIARBEL, J. KEARSLEY, AI'\D BROWI'\, vY.J., AI'\D M.R. ROSEN. 199,5. Was there a Pliocene­ K.R McALLISTER. 1997. Cryptic species of spotted Pleistocene fluvial-lacustrine connection between frogs, Rana pretiosa complex, in western Korth Death Valley and the Colorado River? Quaternary America. Copeia 1997:1-8. Research 43:286-296. GREEN, D.M., TE SIIARBEL, J. KEARSLEY, AI'\D H. KAISER. BeRcH, J.B. 197.5. Freshwater unionacean clams (Mol­ 1996. Postglacial range fluctuation, genetic subdivi­ lusca: Pelecypoda) of !\:orth America. Malacological sion and speciation in the westelll 1\orth Anlerican Publications, Hamburg, MI. spotted frog complex, Rana pretioo·a. Evolution .50: . 1989. Korth American freshwater snails. Malaco­ 374-390. ---I-ogical Publications, Hamburg, Mich. HANI'\IBAL, H. 1910. Valvatidae of the western Korth BeRKY, A.J. 1971. Biomass hlrnovel; respiration, and inter­ America. Kautilus 23:104-107. population variation in the stream limpet Ferrissia HAI'\SEI'\, vY.R. 198.5. Drainage development of the Green rivularis (Say). Ecological Monographs 41:23,5-251. River Basin in sonthwestern vVyoming and its bear­ CALL, RE. 1884. On the QuaternalY and Recent Mollnsca ing on fish biogeography, neotectonics, and paleo­ of the Great Basin with descriptions of new forms. climates. Mountain Geologist 22:192-204. U.S. Geological Survey Bulletin 11:367-420. HEARD, vY.H. 1970. Hermaphroditism in Margaritifera CARLAI'\DER, K.D. 1969. Handbook of freshwater fIshery fabIta (Gould) (Pelecypoda: Margaritiferidae). !\:au­ biolol,,),. Volume I. Iowa State University Press, Ames. tilus 83:113-114. ___. 1977. Handbook of fi-eshwater fishery biology. ___. 1975. Sexuality and other aspects of reproduction Vol. II. Iowa State University Press, Ames. in Anodonta (Pelecypoda: Unionidae). Malacologia CARLISLE, D.M., AND C.P HAWKII'\S. 1998. Relationship 15:81-103. between invertebrate assemblage struchlre, two trout HECK\1AI'\0:, R.A., e.vY. TIIOMPSOI'\, AI'\D D.A. WITITE. 1981. species, and habitat struchlres in Utah mountain lakes. Fishes of Utah Lake. Utah Lake Monograph, Great Basin Naturalist Memoirs 5:107-127. Journal of the !\:orth American Benthological Society 17:286-300. HEI'\DERSOI'\, J. 1924. Mollusca of Colorado, Utah, Mon­ tana, Idaho, and Wyoming. University of Colorado CIIAMBERLII'\, R.Y., AI'\D E. BERRY. 1930. Mollusca from Studies 13:65-223. the Hemy Mountains and some neighboring points · 1931. The problem of the Mollusca of Bear Lake in Utah. Bulletin of University of Utah Biological ~d Utah Lake, Idaho-Utah. Kautilus 44:109-113. Series 21. · 1933. Mollusca of the Yellowstone Park, Teton Park CIIAMBERLII'\, R.V, AI'\D D.T JOI'\ES. 1929. A descriptive ~d Jackson Hole region. Nautilus 47:1-3. catalog of the Mollusca of Utah. Bulletin of Univer­ ___. 1935a. Margaritifera and Fllllninicoia in Wyoming. sity of Utah Biological Series 19. Nautilus 48:107. CLARKE, A.H. 1973. The freshwater molluscs of the Cana­ · 193.5b. Lymnaea auricularia L. and Ferrissia cau­ dian interior basin. Malacologia 13:1-,509. ----,:;na (Cooper) in Colorado. Nautilus 49:68. . 1981. The freshwater molluscs ofCanada. !\:ational --~-'Iuseum · 1936a. Mollusca of Colorado, Utah, Montana, of Kahnal Sciences, Ottawa, Canada. ---I-daho, and Wyoming. University of Colorado Stud­ CeRREY, D.R, e.G. OVIATT, AI'\D G.B. PLYLER. 1983. Lake ies, Supplement 23:81-14.5. Bonneville stratigraphy, geomorphology, and isosta­ · 1936b. Helisoma ammon Gould. Kautilus ,50:41-42. tic deformation in west-central Utah. Utah Geologi­ HEI'\DERSOI'\, J., AI'\D L.E. DAI'\IELS. 1917. Hunting Mol­ cal and Mineral Survey Special Studies 62:6:3-82. lusca in Utah and Idaho in 1916. Proceeding of the CeRRlER, A.O. 1868. The shell-bearing Mollusca of Michi­ Academy of Katural Science, Philadelphia 69:48-81. gan. Kent ScientifIc Institute Miscellaneous Publica­ HENDERSOI'\, J., AI'\D H.G. RODECK. 1934. Kew species of tion, Grand Rapids, MI. Pliocene Mollusca from eastern Oregon. Journal of DeI'\IIAM, J.B., M.M. PEACOCK, B.E. RIE\IAN, R.E. Paleontology 8:264-269. SCHROOTER, AI'\D G.L. VINYARD. 1999. Local and HERSIIEY, A.E. 1990. Snail population in arctic lakes: com­ geographic variability in the distribution of stream­ petition mediated by predation'! Oecologia 82:26--32. living Lahontan cutthroat. Transactions of American HERSIILER, R. 1998. A systematic review of the hydrobiid Fisheries Societv 128:87.5-889. snails (Gastropoda: Rissooidea) of the Great Basin, EARDLEY, A.J., AI'\D Y. 'GVOSDETSKY. 1960. Analysis of Pleis­ western United States. Part I. Genus Pyrgulopsis. tocene core from Great Salt Lake, Utah. Geological Veliger 41:1-132. Society ofAmerica Bulletin 71:1323-1344. HILDEBRAI'\D, S.E, AI'\D I.L. TOWERS. 1927. Food of trout FIRBY, J.R., S.E. SIIARPE, J.E WIIELAI'\, G.R. SMITH, AI'\D in Fish Lake, Utah. Ecology 8:389-397. vY.G. SPAULDII'\C. 1997. Paleobiotic and isotopic analy­ HOE II, vY.R. 1990. Phylogenetic relationships among east­ sis of mollusks, fish, and plants from Core OL-92: em Korth American Anodonta (Bivalvia: Unionidae). indicators for an open or closed lake system. Pages Malacological Review 23:63-82. 121-125 in G.I. Smith and J.L. Bischoff, editors, An HOCCARTII, M.A. 1992. An examination of the glochidia­ 800,000-year paleoclimatic record from Core OL-92, host relationships reported in the literahlre for Korth Owens Lake, southeast California. Geological Soci­ American species of Unionacea (Mollusca: Bivalvia). ety ofAmerica Special Publication 317:121-12.5. Malacology Data Net 3:1-30. 2004] blTER:-fOUNTAIN MOLLUSKS 129

HOVINGH, P 1993. Zoogeography and paleozoology of MURPIIY, G.!. 19.51. The fishery ofClear Lake, Lake County, leeches, molluscs, and amphibians in western Bonne­ Califomia. California Fish and Game 37:439--488. ville Basin, Utah, USA. Journal of Paleolimnology NORTHCOTE, T.G. 1988. Fish in structure and fi.mction of 9:41-.54. freshwater ecosystems: a "top-down" view. Canadian ___. 1997. Amphibians in the eastern Great Basin (Ke­ Journal of Fishery and Aquatic Science 4.5:361-379. vada and Utah, USA): a geographical study with OVIATT, e.G. 1987. Lake Bonneville stratigraphy at the paleozoological models and conservation implica­ Old River Bed, Utah. American Journal of Science tions. Herpetological Katural History .5:97-134. 287:383-398. HOWARD, J.L. 1996. Paleocene to Holocene paleodeltas of 1988. Late Pleistocene and Holocene lake fluctu­ ancestral Colorado River off'et by the San Andreas ations in the Sevier Lake basin, Utah, USA. Journal EmIt system, southern California. Geology 24:783-786. of Paleolimnology 1:9-21. HeBBs, e.L., AND RR MILLER. 1948. The zoological evi­ OVIATT, e.G., WD. McCoy, AND R.G. REIDER. 1987. Evi­ dence. The Great Basin, with emphasis on glacial dence for a shallow early or middle \Visconsin-age and post-glacial times. Bulletin of University of Utah lake in the Bonneville Basin, Utah. QuatemUlY Re­ Biological Series 38:18-166. search 27:248-262. HeNT, C.B. 1981. Pleistocene Lake Bonneville, ancestral OVIATT, e.G., RS. TIIOyIPSON, D.S. KAeFYfAN, J. BRIGHT, Great Salt Lake, as described in the notebooks of AND RM. FORESTER. 1999. Reinterpretation of the G.K. Gilbert, 187.3-1880. Brigham Young University BUlll1ester Core, Bonneville Basin, Utah. Quaternary Geological Studies 29. Research .52:180-184. JACOBSON, M.K. 19.52. The shells of Pyramid Lake, Nevada. PARKER, RR, EM. WILHELM, A:-iD D.W SCIIl:-iDLER. 1996. Kautilus 66: 1.3-17. Recovery of Hesperodiaptamus arcticus population JOlINSON, J.E. 1986. Inventory of Utah crayfish with notes fi.·om diapausing eggs following elimination by stocked on current distribution. Great Basin Katuralist 46: salmonids. Canadian Joumal ofZoolob'Y 74:1292-1297. 625-631. PARyIALEE, P\V 1988. Mollusks and birds from Last Sup­ JONES, D.T. 1940. Recent collections of Utah Mollusca, per Cave. Pages 1-130 in D.K. Grayson, editor, Dan­ with extralimital records from certain Utah cabinets. ger Cave, Last Supper Cave, and Hanging Rock Utah Academy ofScience, Arts, and Letters 27:33--4.5. Shelter: the btmas. Anthropological Papers of the KEATING, S.T., A:-iD R.S. PREZA:-iT. 1998. Effects of stream American Museum of Kahlral HistOlY 66. Part 1. chemistry on the distribution, growth, and diatom PILSBRY, H.A. 1908. Valvata humeralis califarnica n. subsp. colonization of the freshwater limpet, Ferr;ssia r;vu­ Nautilus 22:82. PILSBRY, H.A. AND J.H. FERRISS. 1906. Mollusca of the lar;.\'. Joumal of Freshwater Ecology 13:67-77. Ozarkian fauna. 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Description of new species of the family water-table levels near Yucca Mountain, Kevada, dur­ Unionidae. American Philosophical Society Transac­ ing Quaternary time. Data repository item 9.509. tions 10:2.33-294. Geological Society ofAmerica Bulletin 107:213-230. LEVITON, A.E., RH. GIBBS, E. HEAL, AND e.E. DAWSO:-i. QeADE, J., AND W.L. PRAlT. 1989. Late Wisconsin ground­ 198.5. Standards in helvetology and ichthyology. Part water discharge environments of southwestern 1. Standard symbolic codes for institutional resource Indian Springs Valley, southern Nevada. Quaternary collections in herpetology and ichthyology. Copeia Research 31:3.31-370. 198.5:802-32. RADANT, RD., AND D.E. SAKAGUCHI. 1980. Utah Lake fish­ MCGINNIS, S.M. 1984. Freshwater fishes of California. eries inventory. Final phase II report for the U.S. University ofCalifornia Press, Berkeley. Bureau of Reclamation. MERRICK, G.\V, A.E. HERSHEY, AND M.E. McDONALD. RAWLINGS, M.S., A:-iD L.A. KEEL. 1989. Wildlife and wild­ 1992. Salmonid diet and the size distribution, and life habitats associated with the Humboldt River and density of benthic invertebrates in an arctic lake. its tributaries. Nevada Department of Wildlife Bio­ Hydrobiologia 240:22.5-234. logical Bulletin 10. MINCKLEY, W.L., D.A. HENDRICKSON, AND C.E. BOND. REyHGIO, E.A., AND D. BLAIR. 1997a. Relationship among 1986. Geography of western Korth American fresh­ problematic North American stagnicoline snails (Pul­ water fishes. Pages .519-613 in e.H. Hocutt and E.O. monata: Lymnaeidae) reinvestigated using nuclear Wiley, editors, The zoogeography of Korth American ribosomal DNA intemal transcribed spacer sequence. freshwater fishes. John Wiley and Sons, Kew York. Canadian Journal of Zoology 7.3:1.540-1.54.5. MOYLE, PB. 1976. Fish introductions in California: history . 1997b. Molecular svstematics of the freshwater and ilnpact on native fishes. 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___' 1964, Kotes on the Bonneville Basin Quaternary TAYLOR, n\V, AXD R.C. BRIGHT. 1987. Drainage history of Mollusca collected by Ricbard Ellsworth Call in the the Bonneville Basin. Pages 239-256 ill R.S. Kopp US, Geological Surveys-US, National Museum col­ and R. E, Cohenour, editors, Cenozoic geology of lections, Sterkiana 13:1-,5, western Utah sites for precious metals and hydrocar­ RoscoE, E.J., AND S, REDELIXGS, 1964, The ecolo!,')' of the bon accumulations. Utah Geological Association Pub­ fresh-water pearl mussel Margaritifera margaritifera lication 16, Salt Lake City. (L.), Sterkiana 16:19-32, TRlMRLE, D.E., AND W.J. CARR. 1961. Late Quaternary RUSSELL, RH, 1971. Mollusca of Fish Springs, Juab County, history of the Snake River in the American Falls Utah: rediscovery of Stagllicola pilsbryi (Hemphill, region, Idaho. Geological Society of America Bul­ 1890), Great Basin Naturalist 31:223-236, letin 72:1739-1748, RliSSELL-HuXTER, w.n 1978, Ecology of freshwater pul­ TRYox, G.\V 1863. Descriptions of new species of fresh monates. Pages 335-383 ill V Fretter and J. Peakle, water Mollusca, belonging to the families of Amni­ editors, Pulmonates, Volume 2a. Systematics, evolu­ colidae, Valvatidae and Limnaeidae; inhabiting Cali­ tion and ecology. Academic Press, London, fornia. Proceedings of Academy of Katural Science RliSSELL-HuXTER, \VD., A.J. BURKY, AND R.D. HUNTER. of Philadelphia 3:147-1.50. 1981. Interpopulation variation in calcareous and VAX DER SCHALlE, H. 1970. Hermaphroditism among proteinaceous shell components in the stream limpet, Korth American fi'eshwater mussels. Malacologia 10: Ferrissia rivlliaris, Malacologia 20:2,55-266. 93-112. SAY, T. 1817. Accounts of two new genera and several new VAXXOTE, RL., AXD G.\V MIXSHALL. 1982. Fluvial pro­ species of fresh water and land shells. Joumal of the cesses and local lithology controlling abundance, Academy of Katural Sciences (Philadelphia) 1:123-126, structure, and composition of mussel beds. Proceed­ ___. 1824. Class Mollusca. Ill: Karrative of an expedi­ ings of the National Academy of Science USA 79: tion to the source of the St. Peter's River. ,. under 4103-4107. the command of Major Stephen H. Long (Philadel­ VAUGIIX, C.c., AXD C.M. TAYLOR. 1999. Impoundments phia) 2(appendix):256-265. and the decline of freshwater mussels: a case study ___. 1840. Descriptions of some new terrestrial and of an extinction gradient. Conservation Biology 13: fluviatile shells of Korth America. 1829, 1830, 1831. 912-920. Transylvania Journal, PI" 1-26, \VALKER, B. 1902. A revision of the carinate Valvatas of the SCOTT, \VB., A"ID E.J. CROSS\IA7\. 1973. Freshwater fishes United States. Kautilus 1.5: 121-125. of Canada. Fisheries Research Board of Canada Bul­ ,1906. Kotes on Valvata. Kautilus 20:25-32. letin 184. Ottawa. ==. 1910. The distribution of Margaritifera margari­ SIGLER, W,E 195:3. The rainbow trout in relation to other tifera (Linn.) in Korth America. Proceedings of fish in Fish Lake. Agricultural Experiment Station Malacological Society London 9:126-145. Bulletin 358. Utah State Agricultural College, Logan. , 1916. The Mollusca collected in northeastern Ne­ SIGLER, \VE, W.T. HEL\I, PA. KUCERA, S. VICC, AND G.W. ---;"da by the Walker-Kewcomb expedition of the Uni­ WORK\fAX. 1983. Life history of the Lahontan cut­ versity of Michigan. Occasional Papers of the Museum throat trout Salmo clarki hellshawi, in Pyramid Lake, of Zoology (University of Michigan) 29:1-8. Nevada, Great Basin Katuralist 43:1-29, WALSER, C.A., M.C. BELK, AXD D.K. SIIIOZAWA. 1999. S\IITII, G. R 1978. Biogeography of intermountain fish. Habitat use of leatherside chub (Gila cope;) in the Great Basin Naturalist Memoir 2:17-42, presence of predatory brown trout (Salmo trutta). SXYDER, lO. 1917, The fishes of the Lahontan system of Great Basin Katuralist 59:272-277. Kevada and northeastern California. US. Bureau of WARD, lV 1998. Riverine landscapes: biodiversity pattel11s, Fisheries Bulletin 35:31-86. disturbance regimes, and aquatic conservation, Bio­ STEI7\, R.A., C.G. GOODMAN, AXD E.A. MARSCIIALL. 1984, logical Conservation 83:269-278. Using time and energetic measures of cost in esti­ WARRE7\, R.E. 2000, Western pearl shell (Margaritifera mating prey value for fish predators. Ecology 65: falcata) artifacts from archaeological sites in south­ 702-715. western \Vyoming. Illinois State Museum Quater­ STRAYER, D.L. 1999. Effects of alien species on fi'eshwater nary Studies Program Technical Report 2000-000­ mollusks in Korth America. Journal of the North 07:1-11. America Benthological Society 18:74-98. WARREX, R.E., AND C.R. HARIXGTOX. 2000. Paleoecology TAYLOR, D.\V 1966. SummalY of North American Blancan offreshwater bivalves (Unionoidea) from Pleistocene nonmarine mollusks. Malacology 4: 1-172. deposits in the Old Crow Basin, Yukon Territory. 1970, \Vest American freshwater Mollusca, 1: bib­ Pages 249-284 ill J.J. Saunders, B.W Styles, and G.E liography of Pleistocene and Recent species. San Baryshnikov, editors, Quaternary pale020010gy in Diego Society of Natural History Memoirs 4. the 1\orthern Hemisphere. Illinois State Museum · 1981. Freshwater mollusks of California: a dish'i­ Scientific Papers Volume 27, Springfield. --I-lUtional checklist. California Fish and Game 67: WATTERS, G.T. 1996. Small dams as barriers to freshwater 140-163. mussels (Bivalvia, Unionoida) and their hosts. Bio­ · 1985. Evolution offieshwater dwmages and mol­ logical Conservation 75:79-85, luscs in western Korth America, Pages 26,5-321 ill WELLS, S,G., L.D. McFADDEX, AND lC. DOHREXWEXD. C.J. Smiley, editO!; Late Cenozoic history of the 1987. Influence of late Quatel11aJY climatic changes Pacific 1\orthwest, Pacific Division of AAAS and the on geomorphic and pedogenic processes on a desert Califol11ia Academv of Sciences, San Francisco. piedmont, eastern Mojave Desert, California, Quater­ · 1988. Aspects 'of freshwater mollusc ecological nary Research 27:130-146. ---b-iogeography. Palaeogeography Palaeoclimatology, WESTERLUXD, C.A. 1883. Koch einige von der Vega-Expe­ Palaeoecology 62:511-576. dition gesammelte Mollusken. Kachrichtenblatt der 2004] INTER\10UNTAIN MOLLUSKS 131

deutschen Malakozoologischen Cesellschaft 15: Bonneville Unit Central Utah Project, Bureau of 164-174. Reclamation. WILLIA~fS, JD., M.L. WARREN, K.S. CC~IMfNGS, J.L. HARRIS, WOOLSTENIIULME, J.P. 1942. Uinta mountain mollusks. AND R.J. KEVES. 199.3. Conservation status of fresh­ Nautilus 56:50-55. water mussels of the United States and Canada. WORKYIA1\, C.W., R.A. VALDEZ, W.F SIGLER, AND J.M. Fisheries 18:6-22. HENDERSON. 1979. Studies on the least chub in geo­ WILLIAMS, J.S., A.D. WILLARD, AND V. PARKER. 1962. thennal active areas of western Utah. U.S. Burean of Recent history of Bear Lake Valley, Utah-Idaho. Land Management. American Joumal ofScience 260:24-.36. Wc, S.-K. 1989. Colorado freshwater mollusks. Katural WINGER, Pv., E.J. PETERS, M.J. DONAIIOO, J.R. BARNES, AND History Inventory ofColorado 11. D.A. WIIITE. 1972. A checklist of the macroinverte­ YEN, T.-c. 1946. Late Tertiary fresh-water mollusks from hrates of the Provo Rive]; Utah. Creat Basin Katu­ southeastern Idaho. Journal of Paleontology 20: ralist .32:211-219. 485-494. WINGET, R.I\., J.R. BARNES, L.B. MERRITT, S.R. RUSII­ FORTH, AND D.K. SIIIOZAWA. 1982. Utah Lake water Received 6 June 2001 quality, hydrology and aquatic biology impact analy­ Accepted 15 Jul!! 2002 sis summary for the irrigation and drainage system.

Appendixes 1 through 3 begin on the following page. 132 WESTERN NORTH AMERICAN NATURALIST [Volume 2

ApPENDIX 1. Literature and museum collections used in 14005, 14010, 14036. California: CAS 42308, 42313, the distribution studies. Parentheses denote specimens 42315; MCZ 298973; UMMZ 160000. without catalog numbers. DEATII VALLEY DRAINAGE BASl'.:.-California: Al\SP 25066; LACM 104571, 104581; SBMNH 10540; USNM Margaritifera 6,52801. BON'.:EVlLLE BAS IN.-Literature: Call 1884; Henderson SALTON TROCGIL-California: CAS 907, 22626, 22672, and Daniels 1917; Chamberlin and Jones 1929; Hender­ 22689, 42316, 42320; FMNH 1981,52; SBMNH 10519,5, son 1935a, 1936a (collected at Evanston in 1895); Wool­ 113267; UCM 14305, 17798; UMMZ 50038, 64018, stenhulme 1942; Beetle 1989; Hovingh 1994 observation. 20,5563; USl\M 7072. Wyoming: CAS 154; UMMZ 172947; USNM 477114, OREGON BASI1oiS.-Literature: Hovingh 1996 observa­ 635194-96; UU 13999-14000, 14008. Idaho: ANSP tions. Oregon: Al\SP 2,506,5; LACM 104699, 140692; 365568, OSM 52427, USl\M 652862, UU 14007. Utah: UMMZ 61863, 103211, 103216, 103224, 132278; UU BYU ( ); CAS ,5622; FMNH 111628, 179817; MCZ 63,56, 13465. 199708; OSM 14389,52426; UCM 10311; UMMZ 88498; S10iAKE RIVER DRAINAGE.-Literature: Hovingh 1991, UU 3786, 14004, 14120. 1992 observations. Idaho: OSM 30117; SBMNH 109037, LAIIONTA'.: BAS IN.-Literature: Call 1884, Walker 1916, 110680; UCM 15170. Utah: BYU ( ). Murphy 1942, Frantz and Cordone 1996. Nevada: CAS COLORADO RIVER DT\AINAGE.-Literature: Bequaert and 154; MCZ 6358; OSM 14343, 14348; UMMZ 5560-62; Miller 1973. Arizona: OSM 54268; UMMZ 103246; USl\M 86298, 102561, 120349. California: CAS ( ), USNM 6394, 25466, 86096, 86393, 86398, 128801, 42268; LACM 103889; SBMNH 105586; UCM 20098; 130172, 130180, 150097, 271268-69, 272304. California: UMMZ 195564; UU 14011. LACM 126304. Utah: FMl\H 179804; UU 12159. OREGO'.: BASlNs.-Literature: Pm'malee 1988. Oregon: FMl\H 198170, UU 13736. Gonidea SNAKE RIVER DRAINAGE (CPPER S'.:AKE RlVER).-Litera­ LAII01oiTA1oi BAsIN.-Nevada: USNM 854812, 883,542; ture: Henderson and Rodeck 1934, Henderson 193,5a, UU 11822, 12474-7,5. Bangham 1951, Heard 1970, Beetle 1989. Wyoming: OREG01oi BASINs.-Oregon: UMMZ 61864 (1934). Al\SP 390191; OSM 45703, 45713, 50.516; UMMZ SNAKE RIVER DRAl'.:AGE.-Idaho: Literature: Taylor and 104097, 183402, 229595; USl\M 635192; UCM 29,582; Bright 1987. ANSP 41033, 118401; OSM 30118; UMMZ UU 14071, 14168-69. Idaho: CAS ( ), MCZ 6357, OSUM 227,593. Oregon: OSM 48220. Nevada: UCM 3758; 36275, SBMl\H 107845, USl\M 652860, UU 14166-67. USNM 63,5211-13. Utah: OSM 52423. Middle Snake River and Owyhee River, Idaho: OSM 30116, 30587, 30,589; USl\M 128830, Valvata californica (synonyms in the United States: Valvata 783066. Nevada: UCM 3757. hll1neralis and Valvata hll1neralis californica) BO'.:NEVILLE BASl'.:.-Literature: Call 1884, Chamber­ Anodonta lin and Jones 1929, Jones 1940, Woolstenhulme 1942, BO'.:NEVILLE BASI'.:.-Literature: Call 1884; Henderson Roscoe 1964, Russell 1971, Taylor 1986 communications. and Daniels 1917; Henderson 1924, 1931, 1936a, b; Wyoming: UU 10341, 12901, 14186. Idaho: ANSP 57016, Chamberlin and Jones 1929; Jones 1940; Eardley and 144606, 187744, 187,583; FMNH ,58311, 59943, 76432, Gvosdetsky 1960; Roscoe 1964; Oviatt 1988; Beetle 1989; 179224; MCZ 36,580; UCM 7252, 7263, 7289, 17419; Hovingh 1989, 1992, 1993 observations. Wyoming: OSM UMMZ 3,5908, 97943, 97945; UU 13418, 14064. Utah: 52428, 52511; UU 12902, 13998, 14000, 14009, 14012. ANSP 12022, 46687, 631,52, 76994, 91898, 144628, Idaho: FMNH 179808-9, MCZ 118477, OSM 25794, 14,5,549, 18774.5; CAS 2.572.5, 48976; FMNH 28909, USNM 652863. Utah: Al\SP 25068-69, 129920, 144309; 111911, 224305, 224315, 224518; MCZ 2.520, 2,52.5, BYU ( ), ( ); CAS 157, 159; FMNH 99372, 179803, 36,579,85009; OSM ( ); UCM 7397, 7407, 961,5; UMMZ 179807, 179827, 190806; LACM 114091; MCZ 6543, 42473, 143.563, 197776-77; USNM 47823, 73959, 308926, 6844, 16701, 16758, 16771, 37471, 40371, 103535-36, 74200,5,742018; UU 3672, 9817, 9823, 9829, 9833,10198, 298964-6,5; OSM 24965, 26011, 26014, 26089, 26092, 10202, 10206, 10210-11, 10301, 11914, 12149, 12784, 40550, 52429; SBMNH 109475; UCM 7418, 10580, 12854, 12863, 12891, 13666, 13678, 13684, 1383,5, 13922, 1:3753, 17346, 17:364-65, 17367, 17379, 32028, 33280; 140.57, 14069, 14128, 14140, 14184, 14186, 14188-89, UMMZ 35093, 52261, ,57599-600, 103227, 103232, 14191-92, 14194, 14197. 103240,159995-96, 169777; UNLV ( ); USl\M 86367-68, LAIIO'.:TA'.: BASIN.-Nevada: Al\SP 187746; CAS 104151-52, 308922, 339741, 512227, 524299, .591393, 5,5811; UMMZ 42789, 2293.59; USl\M 272320, 3222,55, 6,52821; UU 7854, 8972, 9851, 12160, 12549, 12,5,52, 477670; UU 14002, 14043, 14097 California: ANSP 12643, 13991, 13993, 13997, 14006, 14013, 14065, 14119. 73649; CAS ( ), ( ),2748,23666,27785-86,51254,55811; Nevada: CAS 23906, 2,5725; UMMZ 132574; UU 11883, USl\M 361,551; UU 14019, 14030. 14003 (1998). INTERIOR BASI'.:s.-Literature: Quade and Pratt 1989. LAIIONTA'.: BAS IN.-Literature: Call 1884; Walker 1916; Nevada: Ul\LV 2089, 3191; USl\M 873176, 874406; UU Murphy 1942; Baily 1950; Jacobson 1952; Benson et al. 9760, 10845, 12908-9, 12941, 13677, 14021, 14196. 1992; McCuire communication 1995; Hovingh 1992, 1997 OREGON BASI1ois.-Oregon: ANSP 1202,5; CAS 32763; observations. Nevada: Al\SP 48272; CAS 5680, 33134, USNM 308990. 42317; MCZ 6541-42, 37472, 298974-7,5; OSM 14372, CREAT PLAl'.:S DRAINAGE.-Colorado: UCM 12266, 17174, 30848; SBMl\H 10363; UCM 20562, 37090; 27411,28036,30435,34498. UMMZ 5555-59, 103192, 103199, 103213, 103234, COLORADO RIVER BASI1oi.-Literature: Chamberlin and 132572-73, 1.59998, 19.5493, 19.5.563, 229.5.5.5; USNM Jones 1929, Chamberlin and Berry 1930, Bequaert and 86371, 86395, 86399, 120905-6, 322254, 472821, 504497, Miller 1973, Beetle 1989, Wu 1989. Arizona: ANSP .519299, (i.52802, 652811; UU 11224, 13690, 13735, 14001, 82994, 146997, 163962; UNLV 3013, 3022, 3215, 3274. 2004] I\lTERMOU\lTAI\I Y10LLUSKS 133

Utah: FMNH 111819; UMMZ 197769-70; UU 14152, UCM 1685,21.505; UMMZ 143591; USl'\M 11812,25012, 141.57, 14160. Wyoming: UMMZ 1.50759, 219534, 28461-62, 30560, 47818-20, .56394, 63991, 121094, 219,558; UMMZ-SSNM (T61-200S); UU 14175, 14178. 225012, 516352, 742023-24, 742026; UU 3716. Nevada: Colorado: UCM 1035,9332,27398,28054,28091,28095. UMMZ 237249 (h111neralis). Los AXCELES BASIN.-Al\SP 12023, 105046, 141363, 143080, 221687, 371408; CAS 23457, 5123,5, 51256; Ferrissia rivularis FMNH 121510; LACM 70047, 70370, 70383, 96142, BOXNEVILLE BASIX.-Literature: Eardley and Gvosdet­ 97657, 106418, 106783, 106798,85-,54, 85-6,5, 85-70, 85­ sky 1960, Russell 1971, Winger et al. 1972, Winget et al. 71; MCZ 56708, 71021, 176708; OSM ( ); UCM 7677-78, 1982, Taylor 1986 communications, Hovingh 1998 obser­ 17846; USl\M 175095,518311; UU 14148. vations. Wyoming: UMMZ 229494, 229503, 229527-29, WEST COAST DRAINACES.-California: USl\M 23411, 229543; UU 12893, 13960. Idaho: UCM 7294, UMMZ 251923. 229502. Utah: ANSP 144620; FMl\H 111820, 178377; SXAKE RIVER DRAINAcE.-Literature: Henderson 1933, MCZ 4578, 24327.5; OSM ( ), ( ); SBMNH UAZ 4802; Beetle 1989. Wyoming: UMMZ 229409, 229425; USl'\M UCM 7410; UMMZ 219474; UU 37,56, 9650, 13390, 536413, UU 14072. Idaho: UU 12963, 14193. Nevada: 13986-88. UU 12987, 13676, 1418,5. Oregon: USNM 308994. LAHOXTAX BASIX.-Literature: Jones 1940, Taylor 1981, McGuire 1992 communications. Nevada: CAS 55811; Valvata utahensis UMMZ 229362; UU 10373, 10375, 10392, 10426, 10431, Literature: Call 1884, Chamberlin and Jones 1929, Tay­ 10917, 11891, 12473, 12476, 12990, 12995, 12999, 13010, lor 1985, Taylor and Bright 1987, Sharp and SWCA Envi­ 13014,13030,13466. California: UU 13427. ronlllental Consultants C0l111l1unications 2003. DEATH VALLEY DRAINACE.-California: SBMl'\H: UAZ BONNEVILLE BAsIN.-Wyoming: UMMZ 229.544. Idaho: 4920. Al'\SP 631.53, 144604, 187689, 187747; FMNH 10,543, SXAKE RIVER DRAIXAGE.-Idaho: CAS ( ), 34168; 58298, 59927, 76423; UCM 7264, 7290; UMMZ 3,5909, UMMZ 219431,2290.53,2290.58,229137,229196,229214, 99653-54, 219293, 229,544; USl\M 52,5096. Utah: Al\SP 229278, 229317, 229374. Utah: UU 11901. Nevada: 12026, 720,59, 322807, :322810; FMNH 28898, 104903, UMMZ 229318, UU 9593. 120949,224329; MCZ 2522-23, 177423; OSM ( ); UCM ORECON BASIX.-Literature: Hovingh 1995 observa­ 7408; UMMZ 996.51, 996.55, 16702.5, 219478, 231776; tions. Oregon: UCM 16002; UMMZ 229138; UU 134,58, USl\M 31277, 173384, .510623, 742016, 742937; UU 13468. 11.51,3611,14038,140.56,14127. COLORADO RIVER BAS IN.-Literature: Be'luaert and LAHOXTAN BAsm.-Nevada: UU 14037. Miller 1973, Wu 1989. Arizona: P Spindler collection; WEST COAST DRAlNACEs.-California: UMMZ 220007. ANSP 115256-,59, 328339; CAS 21093, .52105; FMl'\H SXAKE RIVER DRAIXACES.-Idaho: UU 130,59, 14187. 580,51, 64331; SBMNH UAZ 34.50, 48802; UU 14230-31. Wyoming: UU 13961-62, 13969, 13981, 1:3989, 14183. Valvata virens Colorado: UCM 27274, 27278, 27336, 27343, 27349, WEST COAST DRAlXACES.-Literature: Taylor 1981. Cal­ 273.51,273.56,2806.5,28.500, 3466,5-67; UU 13370, 13406, ifornia: CA 24126; ANSP 12024, 44217, 121828, 121908, 13979-81, 13983-85, 13990. Nevada: Ul'\LV 3432, 3437, 124773, 36.53.58, 371413; LACM 61412, 97393, 12459,5, 3444. 124703, 12470,5, A.8862; MCZ 175922, 17.5992; OSM ( ); 134 WESTER:-I NORTH AMERICAN NATURALIST [Volume 2

ApPE:\DIX 2. Shell m0l1)hometrics of Valvata from the western United States with width (W) in mm, ratio ofwidth and height (W/H), sample standard deviation (±s), and population numher (N). Initial letters denote the geographical region, the first letter indicating the hasin (13, Bonneville; L, Lahontan; G, other hasin in the Great Basin; C, Colorado River drainage; R, Rio Grande drainage; S, Columhia-Snake River drainage; L, Los Angeles Basin) and the second letter indi­ cating the state (U, Utah; !\", !\"evada; C, Colorado; Ca, California; W, Wyoming; Wa, Washington).

Sample (N) Width ±8 W/H ±8

V virens ANSP 3(i5351> (10) ,SA ± 0.2 I.D ± 0.0 V utahensis UU 14056 (11) 5.3 ± 004 1.1 ± 0.1 LN, Gerlach UMMZ 237249 (12) 404 ± 0.3 1.1 ± D.1 LN, Pine Creek UU 140D2 (6) 4.,5 ± 0.2 1.1 ± 0.1 BU, Fish Springs: south UU 14197 (10) 3.6 ± 0.2 1.1 ± 0.1 BU, Fish Springs: north UU 1419,5 (10) 4.3 ± 0.2 1.2 ± 0.1 L!\", Humholdt UU 14D37 (10) 4.6 ± D.2 1.2 ± 0.1 G!\", Toiyahe UU 14196 (10) 5.0 ± D.3 1.3 ± 0.1 G!\", Clover UU 12941 (10) 4.1 ± 0.3 1.3 ± 0.1 CU, !\"avajo Lake FMNH 21>9D9 (10) 4.5 ± DA 1.3 ± 0.1 CC, Gilley UCM 21>091 (10) 4.9 ± 0.3 1.3 ± 0.1 RC, UCM 12266 (10) 3.5 ± 0.2 104 ± 0.1 BU, Utah Lake UU 14057 (10) 3.9 ± 004 104 ± 0.1 BU, Yankee Meadow UU 11914 4.3 ± 004 1.4 ± D.1 CU, Emery UU 141,57 (10) 4.1> ± 0.2 104 ± 0.1 CW, Teton UU 14193 (I» 3.8 ± 0.7 1.4 ± 0.1 BW, Bear River UU 12901 (10) ,5.0 ± 004 104 ± D.1 BU, Hot Springs Lake MCZ 252D (10) 304 ± 0.2 104 ± 0.1 BU, Weher UU 14194 (10) 3.6 ± 0.7 1.5 ± 0.1 SWa, Yakima MCZ 200699 (8) 3.7 ± 0.3 1..5 ± 0.1 CU, Fish Lake FM!\"H 1111>19 (I» 4.1 ± D.6 1.5 ± 0.1 LCa, Big Bear Lake A!\"SP 1D5046 (10) 4.7 ± DA 1..5 ± 0.1 CC, Cahin UCM 21>09,5 (10) 3.1> ± D.3 1.6 ± 0.1 BU, Tnshar UU 91>23, 91>29, 91>33, 91>17 (11) 3.5 ± D.I> 1.6 ± D.1 SWa, Stevens Co. MCZ 176707 (I» 3.1> ± 004 1.6 ± D.1 S!\", Taylor UU14185 (10) 2.6 ± 0.1 1.6 ± D.1 LCa, Bluff Lake UU 14148 (1,5) 4.1> ± 0.3 1.1> ± 0.2 V sincem Great Slave Lake UU 14237 (13) 4.1 ± 0.5 1.9 ± Dj 2004] INTERMOU)/TAI)/ MOLLUSKS 135

ApPE:\DTX 3. Shell measurements of Ferrissia in Intermountain locations and of type specimens. The following ahhre­ viations are used: numher of specimens (N), often comhining several lots within a drainage; length (L), width (W), and height or elevation (H), as defined hy Burch (1989); the ratio of the distance of the apex from the posterior end and the total length (AIL). Upper line, mean:!: s (sample standard deviation, applied to samples with 5 or more specimens). Lower line, range ofmeasurements. Specimens with hodies preserved in alcohol (E); shells only (S).

Basin Length (mm) WIL HIL AIL Suhhasin N (Range) (Range) (Range) (Range)

BO:\:\EVILLE BAsl:\ (E) 29 4.03:!: 0.66 0.63:!: 0.04 0.34:!: 0.04 0.34:!: 0.03 (2.9~5.6) (0.47~0.69) (0.25-0.44) (0.28-0.44) West Bonneville (E) 8 4.05:!: 0.52 0.61 :!: 0.06 0.37:!: 0.04 0.32:!: 0.02 (3.3-4.7) (0.47-0.69) (0.31-0.44) (0.28~0.36) Utah Lake (E) 14 3.92:!: 0.75 0.63:!: 0.04 0.32:!: 0.03 0.36:!: 0.04 (29-,5.6) (0.56-0.67) (0.25-0.38) (0.31-0.44) East Bonneville (E) 7 4.21 :!: 0.65 0.64:!: 0.02 0.37:!: 0.03 0.33:!: 0.02 (3.8-,5.0) (0.63-0.68) (0.32-0.40) (0.31-0.37) East Bonneville (S) 43 4.1.5 :!: 0.,53 0.63:!: 0.04 0.36:!: 0.04 0.36:!: 0.04 (2.9-5.5) (0.50-0.72) (0.29-0.44) (0.29-0.48) S:\AKE RrvER (E) 10 4.02:!: 1.08 0.59:!: 0.(l4 0.34:!: 0.04 0.32 :!: 0.04 (2.5-5.9) (0.51-0.65) (0.30-0.41) (0.27-0.40) S:\AKE RIVER (S) 10 3.68:!: 0.74 0.56:!: 0.06 0.35:!: 0.04 0.37:!: 0.03 (2.9-5.1) (0.48-0.66) (0.29-0.41) (0.32~0.41) LAIlO:\TA:\ BAsr;\ Humholdt River dr. (E) 77 3.96:!: 0.79 0.63:!: 0.04 0.38:!: 0.05 0.34:!: 0.04 (2.3~7.0) (0.49-0.69) (0.29-0.48) (0.24-0.42) Humholdt River dr. (S) 8 3.6:!: 0.29 0.64:!: 0.02 0.35:!: 0.04 0.37:!: 0.04 (3.0~3.9) (0.62-0.67) (0.29-0.42) (0.30-0.43) COLORADO RIVER BASI:\ Upper Green River (E) 9 4.31 :!: 0.77 0.64:!: 0.02 0.38:!: 0.04 0.34:!: 0.03 (3.2-6.0) (0.61-0.67) (0.33-0.45) (0.29-0.37) Yampa River (E) 65 4.30:!: 0.82 0.66:!: 0.03 0.35 :!: 0.04 0.36:!: 0.03 (2.8-6.0) (0.60~0. 73) (0.25-0.44) (0.28-0.45) Yampa River (S) 23 3.63:!: 0.51 0.63:!: 0.03 0.31 :!: 0.05 0.38:!: 0.04 (2.5-4.3) (0.,56-0.67) (0.24-0.42) (0.31-0.45) Sahino Canyon, AZ (S) 4 3.33 0.59 0.31 0.22 (3.0~3.8) (0.,53~0.62) (0.29-0.33) (0.19~0.28) San Pedro (E) 13 3.27:!: 0.56 0.53:!: 0.03 0.32:!: 0.03 0.27:!: 0.03 (2.6-4.6) (0.49-0.60) (0.27-0.38) (0.22-0.32) F. rivularis Al\SP 21982 2 5 0.68 0.38 0.34 (I) (0.66-0.69) (0.35-0.40) (0.33~0.35) F. fragilis Al\SP 220II 1 3.9 0.48 0.31 0.32 F. [Jaral/elus Al\SP 21996 3 4.0 0.57 0.2,5 0.35 (3.6-4.5) (0.,56-0.58) (0.24~0.26) (0.31-0.38) F. walkeri Al\SP 87479 7 3.96:!: 0.54 0.64:!: 0.02 0.26:!: 0.02 0.30:!: 0.03 (3.6-5.1) (0.61~0.66) (0.23-0.29) (0.24-0.32) Queen Charlotte UU 14239 8 6.57:!: 0.90 0.62:!: 0.02 0.32:!: 0.0 0.37:!: 0.3 (5.2-7.7) (0.59-0.66) (0.29-0.37) (0.3,5-0.42)