6,242 research outputs found
A reappraisal of the California Roach/Hitch (Cypriniformes, Cyprinidae, Hesperoleucus/Lavinia) species complex
No full textBaumsteiger, Jason, Moyle, Peter B. (2019): A reappraisal of the California Roach/Hitch (Cypriniformes, Cyprinidae, Hesperoleucus/Lavinia) species complex. Zootaxa 4543 (2): 221-240, DOI: 10.11646/zootaxa.4543.2.
Ecology of the fishes of a Minnesota lake with special reference to Cyprinidae
No full textMoyle, Peter B.. (1969). Ecology of the fishes of a Minnesota lake with special reference to Cyprinidae. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/193819
Cryptic Species of Freshwater Sculpin (Cottidae: Cottus) in California, USA
No full textMoyle, Peter B., Campbell, Matthew A. (2022): Cryptic Species of Freshwater Sculpin (Cottidae: Cottus) in California, USA. Zootaxa 5154 (5): 501-527, DOI: 10.11646/zootaxa.5154.5.
Taxonomy of the Speckled Dace Species Complex (Cypriniformes: Leuciscidae, Rhinichthys) in California, USA
No full textMoyle, Peter B., Buckmaster, Nicholas, Su, Yingxin (2023): Taxonomy of the Speckled Dace Species Complex (Cypriniformes: Leuciscidae, Rhinichthys) in California, USA. Zootaxa 5249 (5): 501-539, DOI: 10.11646/zootaxa.5249.5.1, URL: http://dx.doi.org/10.11646/zootaxa.5249.5.
Hesperoleucus symmetricus subsp. serpentinus Baumsteiger and Moyle 2019, new subspecies
No full textHesperoleucus symmetricus serpentinus Baumsteiger and Moyle, new subspecies Red Hills Roach (Fig. 2) Holotype: Museum of Wildlife and Fish Biology, University of California, Davis, WFC3050, 51.8 mm SL, Horton Creek, Tuolumne County, CA, July 16, 2010. Paratypes. WFC3241–3244, 30.4—40.4 mm SL, same location and date as the holotype, The Red Hills Roach has strong support for a subspecies designation (e.g. Brown et al. 1992; Jones et al. 2002; Moyle 2002), especially given its increased isolation from other populations by New Don Pedro Reservoir (constructed in 1971), unique environmental constraints, and the prevalence (~97%) of the chisel-lip morphotype. Genetic and genomic analyses (Aguilar & Jones 2009; Baumsteiger et al. 2017) also found Red Hills Roach to be highly distinct, easily distinguishable from other CA Roach. In fact, our genomic study indicated a clear break between Red Hills Roach and all other CA Roach sampled in every analysis. With so many lines of support, subspecies status is clearly warranted. Diagnosis. Distinguished from other subspecies of H. symmetricus by their flattened body profile, smaller interorbital distance and fewer pectoral and pelvic rays (Jones et al. 2002; Table 1). The holotype has 8 dorsal rays, 8 anal rays, 12 pectoral rays, and 8 pelvic rays. Description. The Red Hills Roach is a genetically and morphologically distinct minnow adapted for living in small streams flowing through serpentine outcrops. They are typically small, less than 60 mm SL (Brown et al. 1992; Jones et al. 2002) and resemble CA Roach in their general appearance. Red Hills Roach exhibit an elevated frequency of “chisel-lip”, a keratinous projection on the lower lip used for scraping algae (Brown et al. 1992). However there is substantial temporal variation in frequency of the chisel-lip condition amongst CA Roach (Jones et al. 2002). Spawning coloration appears to be similar to that of CA Roach but is more intense. W. J. Jones (pers. comm.) describes it as follows: “The body is dark brown to brassy above, dark black lateral band, and brilliant white below, splashed with black blotches on the sides. Dorsal and caudal fins [are] dark olive-brown to reddish-brown, with the rays often deep-olive and with the nearly clear inter-radial membranes faintly flushed with brassy color; pectoral fins [are] yellowish with orange-red axils and very strong orange coloration at base; anal and pelvic fins [are] bright orange-red at the base with lessening coloration towards the rays. Cheeks and operculum with strong gilt reflections; strong orange coloration is found on the edges of the mouth (especially in males) with some blending into the upper mouth region. A lateral band is more strongly gilt than adjacent parts of body, thus often obscuring the lateral line. In females, the coloration is similar but less intense except for the orange coloration at the base of the paired fins that appears equally intense in both sexes. Males can be distinguished primarily by breeding tubercles on the top of the head.” Distribution. The Red Hills Roach is confined to Six Bit Gulch and its tributary streams: Amber Creek, Horton Creek, Minnow Creek and Poor Man’s Gulch in Tuolumne Co. (Jones et al. 2002). Six Bit Gulch, during rainy periods, flows into the western arm of New Don Pedro Reservoir on the Tuolumne River. In July 2010, Roach were observed in three discontinuous wetted reaches of Horton Creek, which covered approximately 500 meters in total wetted length (P. Moyle, unpublished observations). However, only the lower reach, which extends about 200 meters upstream from the confluence with Six Bit Gulch, appeared to be perennial (as indicated by lush growth of sedges and other riparian vegetation). A natural fish barrier approximately 1.2 km upstream from the confluence likely inhibits Roach from accessing upper Horton Creek. Roach have also been observed in Six Bit Gulch where it is forded by Six Bit Ranch Road and in a pool in Roach Creek. Status. Red Hills Roach merit protection as a threatened or endangered subspecies and rate as an IUCN status of Critical Concern (Moyle et al. 2011, 2015). They have an extremely limited distribution in a very harsh environment and less than 1,000 individuals persist in isolated summer pools (Jones et al. 2002). Their persistence is threatened by fire, depleted stream flows, lack of protection on private lands, and most notably, from invasive fishes. While some habitat is protected in the Red Hills Area of Critical Environmental Concern, much is on private land along a road and remains unprotected. Red Hills Roach has persisted only because of its physiological capacity to endure the extreme environmental conditions found in these small exposed streams. Etymology. Both the common and subspecies name reflect the nature of the rocks through which these small creeks flow. The Red Hills region is named for the color of the soils created by weathering one of the largest outcroppings of serpentine rocks in the Sierra Nevada. Serpentine soils are high in magnesium and other minerals and create conditions in which few species can live. The landscape has a sparse but highly endemic flora (Anacker & Harrison 2012, Harrison 2013) and streams are small and largely unshaded.Published as part of Baumsteiger, Jason & Moyle, Peter B., 2019, A reappraisal of the California Roach / Hitch (Cypriniformes, Cyprinidae, Hesperoleucus / Lavinia) species complex, pp. 221-240 in Zootaxa 4543 (2) on pages 229-230, DOI: 10.11646/zootaxa.4543.2.3, http://zenodo.org/record/261777
Rhinichthys nevadensis subsp. caldera Moyle & Buckmaster & Su 2023, new subspecies
No full textRhinichthys nevadensis caldera, new subspecies, Long Valley Speckled Dace Table 3, Fig. 4. Synonymy: Rhinichthys osculus subsp. Sada et al. 1995:356; Moyle 2002:161. Otherwise see synonyms for Desert Speckled Dace, Rhinichthys nevadensis. Holotype: WFB 5000 (Fig. 4). Standard length 60 mm, fork length 70 mm; White Mountain Research Center, Northeast Pond 37.360618°N 118.329370°W. Inyo County, California, July 29, 2021. Nicolas Buckmaster, Rosa Cox, California Department of Fish and Wildlife Paratypes: WFB 5001-5009 (n=9). Same as holotype. Meristic s: holotype (paratypes) Lateral line scales: 64 (59–80). Lateral line incomplete. Scales above lateral line: 10 (9–12), scales difficult to discern. Scales below lateral line: 9 (6–10), scales hard to discern Dorsal-fin rays: 8(7–8), counts include single unbranched ray. Anal-fin rays: 7 (6–7), counts include single unbranched ray. Pectoral-fin rays 13 (11–12), counts include anterior and posterior single unbranched rays. Pelvic 7 (6–8), counts include single unbranched ray. Caudal-fin rays 19 (19). Diagnosis. The Long Valley Speckled Dace is a cryptic taxon, very similar in its meristics to the Amargosa Speckled Dace (Table 3). They are distinguished from other Speckled Dace by their being endemic to the Long Valley region and having a distinct evolutionary lineage, as revealed by genomics (Su et al. 2022). Adults are small (rarely more than 75 mm SL) and recognizable as Speckled Dace by their thick caudal peduncle, sub-cylindrical body, small fins, small eyes (relative to head), and blunt, pointed snout. In life, they are a bronzy color with light speckling (Fig. 6). Striping is largely absent. Maxillary barbels and a frenum are usually absent. They can be distinguished statistically from similar Amargosa Speckled Dace by slightly higher average numbers of pectoral and pelvic, higher lateral line scale count, lower lateral line pore scale count, and absence of maxillary barbels (Sada et al. 1989, 1995). The following mean counts (standard error) are from Long Valley Speckled Dace collected in Whitmore Hot Springs and at an unnamed spring at Little Alkali Lake (Sada 1989, Table 3): lateral line scales 61.7 (1.4); lateral line scales with pores 19.0 (5.0); dorsal-fin rays 8.0 (0.0); anal-fin rays 7.0 (0.0); pectoral-fin rays 13.0 (0.4); pelvic 7.4 (0.2). Description. Long Valley Speckled Dace are small, active fish with the typical Speckled Dace morphology, as described for the species. Genetics/Genomics. Sada et al. (1989, 1995), using isozymes and morphometrics, were the first to recognize Long Valley Speckled Dace as different from other dace populations in the region. Oakey et al. (2004), Mussmann et al (2020) and Su et al (2022) all found genetic differences that separated Long Valley Speckled Dace from Amargosa and Lahontan Speckled Dace. Distribution. The historic range of this dace was in the outlets of hot springs and associated marshes in the remains of the Long Valley volcanic caldera, just east of Mammoth Lakes, Mono County, as well as in Hot Creek. It quite likely had its origins when Speckled Dace colonized the upper Owens Valley region from the Mono Lake Basin via Adobe Valley, during a late Pleistocene pluvial period. During this time, Mono Lake levels were high enough so that it periodically spilled into Adobe Valley, which drained into the Owens River, from which fish presumably moved upstream into Long Valley. Subsequent down-faulting of the Owens River and formation of steep waterfalls in the Owens River gorge likely isolated Long Valley from the Owens Valley around 100,000 years ago (Hildreth and Fierstein 2016). Note. Long Valley Speckled Dace were considered to be one of the scattered populations of Owens Valley Speckled Dace until Sada et al. (1993, 1995) showed it was genetically and morphometrically distinct and that it was closely related to dace populations in Ash Meadows, Amargosa River, and elsewhere in Owens Valley and Death Valley. Moyle (2002) and Moyle et al. (2015) recognized it as an undescribed subspecies. Our analysis shows that the Long Valley Speckled Dace is a distinct lineage confined to a small part of the Owens Valley region. It merits subspecies designation based on the following lines of evidence. Taxonomy. Multiple analyses indicate that Long Valley dace is a distinct lineage (subspecies) within Desert Speckled Dace, R. nevadensis (Oakey et al 2004, Mussmann et al. 2020, Sada et al. 1995, Moyle 2002, Moyle et al. 2015 and Su et al., 2022). Geography/geology. During pluvial periods of the Pleistocene, the Death Valley region was a series of interconnected large lakes, with abundant fishes (Hubbs and Miller 1948). When the climate changed and heavy precipitation stopped falling, the lakes and rivers dried up or became small remnants of what they once were. This process resulted in numerous isolated Speckled Dace populations with little, or at least very infrequent, opportunity for genetic exchange. See Desert Speckled Dace account for more details. Long Valley is part of the Death Valley regional endemism hotspot with numerous endemic plants and animals, including fishes (Sada et al. 1995). Long Valley Speckled Dace can be regarded as another organism endemic to the isolated Owens Valley region. Genetics/genomics. Sada et al. (1993, 1995) were first to recognize that Long Valley Speckled Dace were genetically distinct from other dace, a finding confirmed by other studies (Mussmann et al. 2020, Su et al. 2022). See Amargosa Speckled Dace (R. nevadensis nevadensis) description for more details. Etymology. The Long Valley Speckled Dace was historically known only from small streams flowing into the Long Valley Caldera, the remnants of a gigantic volcano that last erupted 0.7 million years ago (Hildreth and Fierstein 2016). They colonized the remnants of the caldera during the late Pleistocene, hence caldera. Conservation Status. Long Valley Speckled Dace have been extirpated from all but one of their historic collection sites, including Hot Creek. The only population left in its native range (as of 2021) is in Whitmore Marsh and its inlet stream in Long Valley (Moyle et al. 2015). Unfortunately, this marsh is now maintained by the outflows of a hot spring system that has been developed as a public swimming pool by the Town of Mammoth Lakes. Discharge is approximately 2 cfs and is lightly chlorinated. The outlet stream feeds an alkaline marsh of roughly 1 acre. In 1989, dace occupied 250 meters of stream and two large shallow ponds less than a half meter deep (Moyle et al 2015). Surveys in 2002 and 2009 by CDFW found this population to be relatively stable (S. Parmenter, CDFW, pers. comm. 2009). In 2018, 2019, and 2020, they were not found in these habitats (S. Parmenter, CDFW, in Center for Biological Diversity, 2020). However, in 2021 and 2022, trapping produced a few fish (R. Black, CDFW, pers. comm, 2021). The only other population is in a single artificial pond into which they were introduced at the White Mountain Research Center, outside their native range; the status of this dace population is checked by CDFW on a routine basis (R. Black, CDFW, pers. comm.). The multiple causes of decline are discussed in Moyle et al. (2015) and Center for Biological Diversity (2020). The CBD (2020) has petitioned to have this dace listed as endangered under the federal ESA or else have all Speckled Dace in the Death Valley region included under the 1984 listing of Ash Meadows Speckled Dace as endangered. It is listed as a Species of Special Concern (critical concern) by CDFW.Published as part of Moyle, Peter B., Buckmaster, Nicholas & Su, Yingxin, 2023, Taxonomy of the Speckled Dace Species Complex (Cypriniformes: Leuciscidae, Rhinichthys) in California, USA, pp. 501-539 in Zootaxa 5249 (5) on pages 523-524, DOI: 10.11646/zootaxa.5249.5.1, http://zenodo.org/record/770135
Cottus gulosus subsp. wintu Moyle and Campbell 2022, new subspecies
No full textCottus gulosus wintu Moyle and Campbell 2022. Sacramento Riffle Sculpin, new subspecies. Description as for C. gulosus (Table 1, Fig. 1). Characteristics of C. g. wintu used in this study (n=15) are as follows: anal fin rays (12–15), dorsal spines (7–10), dorsal rays (14–19), dorsal fins joined? (variable), black spot on dorsal (yes), palatine teeth present (variable), mouth vs eye (variable but maxilla mostly reaches mid-eye), chin pores (0–2), pelvic fins spines + rays (1+3), pelvics fins mostly do not touch vent, pectoral fin rays (14–16), preopercular spines (1–2), lateral line variable, lateral line pores (26–38). Other characters are listed in Table 1. Holotype. WFB 3424. 78 mm SL, 96 mm TL. Fig. 1. North Fork Feather River, Butte County, California. Coll. Jason Baumsteiger, Oct. 5, 2017. Anal-fin rays 13; dorsal-fin spines 8; dorsal-fin rays 17; dorsal fins joined; dorsal fin spot present; palatine teeth absent; maxilla reaches middle of eye; 1 chin pore; pelvic fins 1 spine, 3 rays; pelvics do not touch vent; pectora1 fin rays 14; preopercular spines 1; lateral line complete; lateral line pores, 35; axillary prickles present. Paratypes (4). WFB 3425–3428. 78–89 mm SL, 96–108 TL. Anal-fin rays 13; dorsal spines 8; dorsal-fin rays 17–18; dorsal fins joined; dorsal fin spot present on 3; palatine teeth absent; maxilla reaches middle of eye; 1–2 chin pores; pelvic fins 1 spine, 3 rays; pelvics do not touch vent; pectora1 fin rays 15; preopercular spines 1; lateral line complete; lateral line pores, 36–41; axillary prickles present. Distribution. Found in the Sacramento River watershed (northern Central Valley), from the American River (and tributaries) north to Shasta Dam. Above Shasta Reservoir, it occurs primarily in the upper Sacramento River and its tributaries (Baumsteiger et al. 2014). Other tributaries to Shasta Reservoir (e.g. McCloud River, Squaw Valley Creek) support C. pitensis, while the reservoir itself supports C. asper (Prickly Sculpin). It inhabits cool-water permanent tributaries and rivers and rivers below dams, where reservoir releases provide cool water (generally less than 24°C). Etymology. The species name honors the Wintu people who were the region’s original inhabitants, with their lands encompassing many of the streams and rivers where this subspecies lives. The Winnemem Wintu (The Middle Water People) still live in the area and are working to restore salmon runs and to protect sacred rivers and sites in the region.Published as part of Moyle, Peter B. & Campbell, Matthew A., 2022, Cryptic Species of Freshwater Sculpin (Cottidae: Cottus) in California, USA, pp. 501-527 in Zootaxa 5154 (5) on page 517, DOI: 10.11646/zootaxa.5154.5.1, http://zenodo.org/record/665547
Cottus ohlone Moyle and Campbell 2022, new species
No full textCottus ohlone Moyle and Campbell 2022. Coastal Riffle Sculpin, new species urn:lsid:zoobank.org:act: 8F6E51D6-5317-4F4E-9246-B2F30FBE7207 Description as for C. gulosus. Meristics of sculpins used in this study (Table 1, n = 45): anal-fin rays (12–14), dorsal spines (6–9), dorsal-fin rays (15–19), dorsal fins joined? (variable), black spot present on dorsal, palatine teeth usually present (variable), mouth vs eye (variable but maxilla mostly reaches mid-eye), chin pores (0–2), pelvic fin spines + rays (1+3), pelvics do not touch vent, pectoral-fin rays (14–16), preopercular spines (2), lateral line (complete/incomplete, variable), lateral line pores (25–35). Other characters are listed in Table 1. Holotype. WFB- 3402. 65 m SL, 79 mm TL from Guadalupe Creek, Santa Clara County, California. November 18, 1986. Collected by Jerry J. Smith (Fig. 1). 65 mm SL, 79 mm TL. Anal fin rays 13; dorsal fin spines 8; dorsal fin rays 19; dorsal fins joined; dorsal fin spot present; palatine teeth absent; maxilla reaches middle of eye; 1 chin pore; pelvic fins 1 spine, 3 rays; pelvics do not touch vent; pectora1-fin rays 15; preopercular spines 1; lateral line incomplete; lateral line pores, 27; axillary prickles present but small. Paratypes. WFB-3403, 3404, 3405, 3406 from same location. 58–60 mm SL, 74–81 TL. Anal-fin rays 13; dorsal fin spines 8; dorsal fin rays 17–19; dorsal fins variable in joining; dorsal fin spot present; palatine teeth absent; maxilla reaches middle of eye; 1–2 chin pores; pelvic fins 1 spine, 3 rays; pelvic fins do not touch vent in 3 of 4; pectora1 fin rays 13–15; preopercular spines 1; lateral line incomplete in most; lateral line pores, 26–33; axillary prickles present but small. Diagnosis. Distinguished from other members of the C. gulosus complex as a distinct lineage as determined by molecular phylogenetic and population genomic evidence (Baumsteiger et al. 2014, this study) and by its limited distribution (Fig. 2). Distribution. Restricted to drainages flowing west or southwest along the Coast Range Mountains of California, with two distinct lineages, described as subspecies here. The watersheds include (a) the Russian River and Redwood Creek (which flow directly into the Pacific Ocean, (b) the Napa River, Sonoma Creek and nearby watersheds that flow into north San Francisco Bay, (c) streams draining the Diablo and Coastal ranges through the Santa Clara Valley and nearby areas and flowing into south San Francisco Bay, and (d) tributaries to the Pajaro River, in the Salinas River watershed (Fig. 2). Populations may also exist in the headwaters of the Salinas River (Snyder 1913) although there are no recent records. Habitats are restricted to cool, clear permanent streams with rocky riffles, mostly in headwaters. Etymology. Ohlone honors the Ohlone peoples, who were the original human inhabitants of the Santa Clara Valley region and much of the southern San Francisco Bay region (see http://www.muwekma.org/). The name Ohlone refers to the more than 50 peoples that spoke similar languages and interacted with one another in the region. Their descendants are largely encompassed in the present-day Muwekma Ohlone Tribe.Published as part of Moyle, Peter B. & Campbell, Matthew A., 2022, Cryptic Species of Freshwater Sculpin (Cottidae: Cottus) in California, USA, pp. 501-527 in Zootaxa 5154 (5) on page 518, DOI: 10.11646/zootaxa.5154.5.1, http://zenodo.org/record/665547
FIGURE 5 in Cryptic Species of Freshwater Sculpin (Cottidae: Cottus) in California, USA
No full textFIGURE 5. Admixture analysis of all sampling locations from K = 2 to 6 genetic clusters. Sampling locations along the x-axis are color coded by sampling location as in Figure 4 and correspond to Table 2. Cottus taxa are designated on the x-axis.Published as part of Moyle, Peter B. & Campbell, Matthew A., 2022, Cryptic Species of Freshwater Sculpin (Cottidae: Cottus) in California, USA, pp. 501-527 in Zootaxa 5154 (5) on page 513, DOI: 10.11646/zootaxa.5154.5.1, http://zenodo.org/record/665547
Rhinichthys klamathensis subsp. klamathensis Moyle, Buckmaster & Su, 2023, new combination
No full textRhinichthys klamathensis klamathensis, new combination, Klamath Speckled Dace, Fig. 6 Synonymy. Same as for Western Speckled Dace, R. klamathensis. Holotype and paratypes are the same as for Western Speckled Dace, R. klamathensis. Diagnosis. Same as Western Speckled Dace, R. klamathensis; the Speckled Dace lineage that is abundant in the streams, lakes, and other aquatic habitats in the Klamath River Basin in Oregon and California, including the Trinity River in California. Distinguished statistically by having somewhat smaller scales (scales in lateral line, 68–78; mean 73, n =49) than the other two subspecies (Sacramento, 54–83, mean 70, n=123; Warner, 68–71, mean 69, n=58). Otherwise, it is not distinguishable from other Speckled Dace except by genomics and distribution. Description. Evermann and Meek (1898) described this cryptic subspecies as Agosia klamathensis. Therefore, the description quoted in the Western Speckled Dace account is also for this subspecies, and it applies to the other two subspecies as well. Distribution. The Klamath Speckled Dace is found throughout the Klamath Basin in Oregon and California, including the Klamath and Trinity rivers and tributaries, as well as in the Rogue River to the north (Wiesenfeld et al. 2017). It is also widespread in the upper Klamath Basin, including Upper Klamath Lake. The Speckled Dace in the Eel River, to the south of the Klamath Basin, is an introduced population of R. k. klamathensis (Kinziger et al. 2011). Geology/zoogeography. The geologic history of the Klamath region is complex. The Snake River, now a tributary to the Columbia River, was once a major river that originated in the Idaho region and flowed to the ocean via the ancestral Klamath River during the Pliocene (Minckley et al. 1986, Smith et al 2017). When the Snake broke through to the Klamath, it carried with it the lake fauna of the Great Basin, which gave rise to the presentday endemic, freshwater-dispersing fish fauna (12 species) of the upper Klamath basin (Moyle 2002), presumably including Speckled Dace. Pfrender et al. (2004:498), using a molecular clock based on mtDNA from Speckled Dace from the major river basins of Oregon, speculated that “…the levels of sequence divergence in R. osculus among these major basins are more consistent with a Pliocene or Miocene sundering of gene flow between major basins. Miocene isolation of these river systems is substantially earlier than has previously been suggested.” They thought such ancient divergence could explain the genetic diversity found in dace within the Klamath basin, a diversity that was also documented by Wiesenfeld et al. (2017). See also the geology discussion under Western Speckled Dace. Geographically, Klamath Speckled Dace co-occur with other fish species endemic to the Klamath watershed. However, the endemic fishes in the upper watershed (above Klamath Falls) are different from those in the lower river and it appears that dace from the two regions diverge as well, a situation noted also for Marbled Sculpin, Cottus klamathensis (Daniels and Moyle 1984). Genetics/genomics. The genomic study of Su et al. (2022) unveiled the three lineages within R. klamathensis, as discussed. Within the Klamath drainage, Wiesenfeld et al. (2017:8), using analyses of microsatellites and mtDNA, found that The Klamath–Trinity Basin Speckled Dace were resolved as nearly monophyletic [bootstrap (BS) 77], and exhibited a sister group relationship with nearby basins in California and Oregon (Sacramento, Pit River, and Goose Lake). The Klamath River and Trinity River populations, however, were found to be sufficiently distinct to suggest the two rivers were once isolated from one another, with their connection being fairly recent. The presence of apparent hybrids in the region where the two rivers meet today also supports this conclusion (Wiesenfeld et al. 2017). A genetically distinct population is also found in Jenny Creek, a tributary to the Klamath River that is largely in Oregon (Wiesenfeld et al. 2017). Pfrender et al (2004) used mtDNA to compare dace from the upper Klamath and Rogue rivers with those from two tributaries to the Columbia River in Oregon. They found species-level differences between dace in the two great watersheds, with estimated divergence times of 3.9 to 9.6 million years ago. Within the upper Klamath basin, Pferender et al. (2004) found considerable genetic structure but of more recent origin (<1 million years), including Jenny Creek as a distinct population. Overall, analysis of mtDNA data of dace from their entire range showed that dace from the Klamath, Sacramento, and Warner basins share much of the same lineage; together they form a separate lineage within the Northwest clade of Smith et al. (2017). Note. The Klamath Speckled Dace was originally described as a species that differed from other Speckled Dace by having finer scales (Evermann and Meek 1898). Subsequently, it retained its identity as a subspecies, R. osculus klamathensis. This is not surprising given that the Klamath Basin has long been recognized as an isolated basin which supports high endemism in its fishes (Moyle 2002). The Klamath Speckled Dace has retained its identity through the region’s complex geologic history, enduring the rise of mountain ranges, high levels of vulcanism, and invading interior rivers (Minckley et al. 1986). This complex geologic history has kept the Klamath fish fauna isolated and distinct. In the upper Klamath basin, Speckled Dace live with other endemic fishes that had their ancestors in the Great Basin. Even in the lower Klamath River, which is too swift for the lake-adapted fishes of the upper basin, it co-occurs with the endemic Klamath Smallscale Sucker, Catostomus rimiculus (Moyle 2002). Given the genetic structure that Wiesenfeld et al. (2017) found in the basin, it is possible that dace populations from the upper and lower river should be treated as separate subspecies. Su et al. (2022) confirmed results from other genetic methods that the Klamath Speckled Dace is a distinct evolutionary lineage. Etymology. The Klamath Speckled Dace is named for the river system to which it is endemic. The river is named for the native peoples who lived (and still do) in the upper Klamath Basin. Conservation Status. The Klamath Speckled Dace is widespread and abundant in streams and natural lakes in the Klamath Basin, including the Trinity River. The main concern is that some distinct populations, such as in Jenny Creek, may be lost as the waters are dammed and diverted. The genetic diversity of Speckled Dace populations within the river system is just beginning to be appreciated (Pfrender et al. 2004; Wiesenfeld et al. 2017).Published as part of Moyle, Peter B., Buckmaster, Nicholas & Su, Yingxin, 2023, Taxonomy of the Speckled Dace Species Complex (Cypriniformes: Leuciscidae, Rhinichthys) in California, USA, pp. 501-539 in Zootaxa 5249 (5) on pages 526-528, DOI: 10.11646/zootaxa.5249.5.1, http://zenodo.org/record/770135
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