Rhinichthys klamathensis goyatoka, Moyle & Buckmaster & Su, 2023

Moyle, Peter B., Buckmaster, Nicholas & Su, Yingxin, 2023, Taxonomy of the Speckled Dace Species Complex (Cypriniformes: Leuciscidae, Rhinichthys) in California, USA, Zootaxa 5249 (5), pp. 501-539 : 531-532

Rhinichthys klamathensis goyatoka , new subspecies. Warner Speckled Dace

Fig. 4C

Agosia nubila carringtoni Snyder 1908:98

Agosia robusta Rutter 1908: 139

Apocope carringtoni Evermann and Clark 1931:55

Rhinichthys osculus subsp. Williams et al. 1990:243

Rhinichthys osculus klamathensis Markle 2016:50

Holotype: WFB-122-10-44 ( Figure 1 ). 59 mm SL. Twelve Mile Creek , Lake County, Oregon. Jack E. Williams. November 2, 1988.

Paratypes: WFB-122-10-42a—122-10-42j (n = 10). Same location and collector

Meristics: Holotype (paratypes)

Length (mm): standard 59; fork 67; total 71

Lateral line scales: 76 (61–84). Lateral line incomplete in most individuals; counts include 2–3 scales beyond end of lateral line.

Scales above lateral line: 13 (11–14)

Scales below lateral line: 11 (9–13)

Dorsal-fin rays: 8(8), counts include single unbranched ray.

Anal-fin rays: 7 (7), counts include single unbranched ray.

Pectoral-fin rays 12 (10–13), counts include unbranched rays.

Pelvic 7 (7–9), counts include unbranched rays.

Caudal-fin rays 19 (19–20).

Diagnosis. Genetically distinct Speckled Dace endemic to the isolated Warner Basin in Oregon and California. Relatively small adult size (<10 cm SL); classic Speckled Dace body shape: thick caudal peduncle, robust (subcylindrical) body, small fins, and bluntly pointed snout with subterminal mouth. Maxillary barbels and frenum usually present.

Description. The description is the same as Sacramento Speckled Dace. Snyder (1908) examined Speckled Dace from throughout the arid basins of southeastern Oregon and could find no distinguishing morphological or meristic features to separate Warner Speckled Dace from dace in other basins, not even lateral line scale numbers (which partially define Klamath Speckled Dace). For lateral line scales, Snyder’s counts were: Warner Basin 68– 71(N=58), Sacramento, 61–74 (N=143), and Klamath 68–78 (n=18). He also noted that in Warner Speckled Dace, maxillary barbels were usually present (45 out of 53 fish examined). For comparison, they were present on 43/48 Klamath basin dace but only 9/68 for Sacramento basin dace. A frenum is usually present.

Distribution. In a survey of fishes of the Warner Basin, Williams et al. (1990) found Speckled Dace in Twelvemile Creek, Twentymile Creek, Deep Creek, and upper Honey Creek, plus the isolated Foskett Spring. Only Twelvemile Creek has headwaters (and Speckled Dace) in California. Foskett Spring is on the edge of Coleman Lake, on the southeast corner of the basin; the lake is dry most of the time. The mtDNA study by Smith et al. (2017) indicates Speckled Dace in the Warner Basin share a recent ancestry with those from the Chewaucan River to the north (which flows into Lake Abert, Oregon) and with those in Wall Canyon Creek (Nevada) to the southeast. Further genomic studies may show these populations could be included within Warner Speckled Dace.

Geology. The Warner Valley is one of a number of isolated watersheds within the northern Great Basin, which have a long complex history of occasional connectivity to big river systems, such as the Snake and the Klamath ( Smith et al. 2002). The onset of Great Basin faulting and uplift of the Warner Range (ca. 3 mya) likely resulted in a permanent separation and isolation of the Warner Basin from the Sacramento and Klamath basins, sometime in the late-Pleistocene (~1.0 mya) (Eggar et al. 2011). This isolation is reflected in other endemic fishes which co-occur with Warner Speckled Dace: Warner Sucker ( Catostomus warnerensis ), Great Basin Redband Trout ( Oncorhynchus mykiss subsp.) and Tui Chub ( Siphatales bicolor subsp.) ( Williams et al. 1990; Markle 2016). In fact, the Warner Valley is one of a number of isolated watersheds within the northern Great Basin that support endemic aquatic species (Hubbs et al. 1978), so it is likely that Speckled Dace are endemic to other watersheds as well.

Genetics/genomics. Ardren et al. (2010), using mtDNA, suggested that Speckled Dace in the Warner Basin are different at the species level from dace in the neighboring Goose Lake Basin (Sacramento drainage). Hoekzema and Sidlauskas (2014) examined mtDNA from dace populations in the Warner Basin and in surrounding basins in Oregon. They found a high level of genetic divergence in dace from the basins, dating to the Pliocene or early Pleistocene, which “…should likely be elevated to species-status once their full geographic extent is discovered, and their morphological diversity described ( Hoekzema and Sidlauskas 2014:245). Distinct lineages included fishes from Goose Lake, Silver Lake, Lake Abert, and the Warner basin, including Foskett Spring. The mtDNA study of Smith et al. (2017) and the genomic study of Su et al. (2022) both indicate that Warner Basin Speckled Dace are a distinct lineage, divergent from the Sacramento and Klamath lineages, at the subspecies or species level.

Etymology. The name honors the Goyatöka people who, before the invasion of their homeland by Euro- Americans, lived on lands in the Warner Basin where Speckled Dace occupied the streams, lakes, and springs ( Dixon 1908, Stewart 1939). The common name indicates the geographic location of the dace populations. The basin is named for William Warner, an army officer who died while mapping the region.

Notes. Our study supports the finding that the Warner Speckled Dace is a distinct lineage (subspecies) allied with Klamath and Sacramento Speckled Dace. Ardren et al. (2010) and Su et al. (2022) show that Warner Speckled Dace have evolutionary ties to the daces in the Klamath and Sacramento Basins. These Speckled Dace became a species of interest when dace in Foskett Spring, in an isolated part of the Warner Basin, were listed as a threatened species without any special taxonomic designation. Subsequent genetic analyses revealed Foskett Spring Speckled Dace could at best be considered a Distinct Population Segment of Warner Speckled Dace; these same analyses suggested that Speckled Dace throughout the Warner Basin constituted a distinct taxon ( Ardren et al. 2010).

Conservation Status. Most of what is known about the Warner Speckled Dace and other fishes of the basin comes from surveys for (a) Warner Sucker, which was listed as threatened in 1985, (b) Foskett Spring Speckled Dace, which was also listed as a threatened species in 1985 (USFWS 2019, https://ecos.fws.gov/ecp/species/651), and (c) Great Basin Redband Trout. The Foskett Spring Speckled Dace was delisted in 2019 as the result of extensive habitat improvement, although it remains a conservation dependent species (USFWS 2019). Most of the permanent water in the basin inhabited by the Warner Sucker is dominated by non-native fishes, but a population of native Tui Chub is also present ( Williams et al. 1990). The remaining Warner Speckled Dace populations (and those of Warner Sucker and Tui Chub) probably qualify for listing as Threatened under the federal ESA. Their decline is due to the combined problems of non-native predatory fishes occupying much of the aquatic habitat, inadequate management of grazing and diversions, and climate change/drought reducing flows and increasing temperatures in streams ( Williams et al. 1990).

Figures

FIGURE 1. Top: Lahontan Speckled Dace (ca. 70 mm TL) and cover habitat in Taylor Creek, California, a tributary to Lake Tahoe. The body shape, stripe on head, and speckling are characteristic of live fish in many populations from Mexico to Canada that have been considered to be just one species, Speckled Dace (Rhinichthys osculus). Photo by T. L. Taylor, July 17, 1991. Bottom: Preserved specimen of Sacramento Speckled Dace, collected by John Otterbein Snyder from Alameda Creek, California in 1898, showing basic external anatomy. Note the presence of tiny maxillary barbels on head, an example of a distinctive characteristic of some populations. Photo by Jon Fong, California Academy of Sciences, of specimen SU 16172.

FIGURE 4. Holotypes of new taxa of Rhinichthys described in this paper, A. Santa Ana Speckled Dace (R. gabrieleno WFB 3498. B. Long Valley Speckled Dace (R. nevadensis caldera) WFB 5000, C. Warner Speckled Dace (R. klamathensis goyatoka) WFB 122-10-44, D. Sacramento Speckled Dace (R. klamathensis achomawi) WFB 3171.