121,917 research outputs found
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
Rhinichthys klamathensis subsp. achomawi Moyle & Buckmaster & Su 2023, new subspecies
No full textRhinichthys klamathensis achomawi, new subspecies. Sacramento Speckled Dace. Figs. 1, 4D, Synonymy. See R. klamathensis account for subspecies synonymies. Holotype: WFB-3171 (Figure 1), 70 mm SL. Bear Creek at Pondosa Bridge, 1.6 km SW of Pondosa, Siskiyou County, California. 41.1884°N - 121.700667°W. July 20, 2015. Jason Baumsteiger, Mollie Ogaz, Christopher R. Jasper, Tyler R. Goodearly, and Matthew J. Young Paratypes WFB - 3171a-3171i (n=9). data the same as holotype. Meristics: holotype (paratypes) Standard length: 70 (41–56 mm) Lateral line scales: 74 (63–73). Lateral line incomplete in most; counts include 2–3 scales beyond lateral line. Scales above lateral line: 13 (11–14) Scales below lateral line: 9 (8–10) Dorsal-fin rays: 8(8), counts include single unbranched ray. Anal-fin rays: 7 (7), counts include single unbranched ray. Pectoral-fin rays 15 (12–15), counts include unbranched rays. Pelvic 7 (8–9), counts include unbranched rays. Caudal-fin rays 19 (19). Basic morphology is described below. Barbels and frenum are usually present. Diagnosis. Same as for Western Speckled Dace, R. klamathensis. Distinguished by distribution and genomics as the Speckled Dace endemic to aquatic habitats in Sacramento River drainage basin and associated coastal drainages. Description. Sacramento Speckled dace are identical to Klamath, Warner, and Lahontan Speckled Dace based on meristics and morphometrics. This is presumably the reason they have been undescribed for so long. The general description of Speckled Dace in Moyle (2002:161) was based on Sacramento dace, so fits the subspecies well: The Speckled Dace is a small (usually <8 cm SL, occasionally to 11 cm SL), highly variable species distinguished by a thick caudal peduncle, a small subterminal mouth, a pointed snout, and small scales (47–89 in lateral line). The origin of the dorsal fin (6–9 rays, usually 8) is well behind that of the pelvic fins. The anal fin normally has 7 rays (6–8). The pharyngeal teeth (1,4-4,1 or 2,4-4,2) are strongly hooked and have only a slight grinding surface Color is highly variable but most fish over 3 cm SL have dark speckles on the sides and back, dark blotches on the sides that often coalesce to resemble a dark lateral band, and a stripe on the head that runs through the snout. The background color on the back and sides is dusky yellow to dark olive, with the belly yellowish to whitish. The bases of the fins of both sexes turn orange to red during breeding and males often have red snouts and lips as well. Presence of maxillary barbels and a frenum is variable. Rutter (1908:140) noted that Sacramento dace were quite variable in their characteristics and found that Sacramento dace from 12 localities (n=94) had 49–77 scales in the lateral line, 7–9 dorsal rays, and 6–8 anal rays. Cornelius (1969) using data from six localities, counted 54–82 scales on the lateral line (mean 70, n = 123); other counts: scale rows above the lateral line (12–20, mean 16, N = 124) scale rows below lateral line (10–19, mean 14, n = 121), vertebrae (34–39, mean 37, n=99), dorsal-fin rays (7–9, mean 8, n=131), anal-fin rays (5–8, mean 7, n =129). See also Table 3. Distribution. The Sacramento Speckled Dace is found in streams and lakes in the Goose Lake (Oregon and California) and Pit River watersheds, the Sacramento River and its tributaries, the Salinas basin, and, in the far south, San Luis Obispo Creek, Arroyo Grande, and the Santa Maria River (Figure 3). It is conspicuous by its absence from the San Joaquin River watershed, although Rutter (1908) collected two small dace from the Kings River at Centerville. Collections made on Los Gatos Creek, an east-side tributary to the San Joaquin River, in 1941 contained Speckled Dace but there are no records of them since then (R. Leidy, pers. comm., 2021). Sacramento Speckled Dace are absent naturally from the Russian River watershed and from all other coastal watersheds, except the San Lorenzo River, Salinas River, San Luis Obispo Creek and the Santa Maria River in southern California. They are also absent from Clear Lake (Lake County) and its tributaries. However, they are present in Cache Creek which flows out of Clear Lake (Moyle 2002, unpublished data). Zoogeography. The Sacramento basin is a large, well-defined region, isolated by the Sierra Nevada Range on the east, the Coast Range on the west, and the Cascade Range in the north. The ancestors of this highly endemic freshwater dispersant fish fauna have ancient roots in ancient lakes and rivers of the region to the east, now drained mostly by tributaries to the Snake River (Minckley et al 1986; Moyle 2002). Speckled Dace presumably entered the region by first colonizing the Klamath Basin with other Great Basin fishes and then by expanding their population to the Sacramento-San Joaquin basin when Klamath River headwaters connected to the region via the Pit River. Dace then found it possible to colonize most of the entire basin (except where noted), reaching as far south as the Santa Maria River (via the Pajaro-Salinas River system). The Sacramento Speckled Dace thus became a member of one of the most highly endemic assemblages of freshwater dispersing fishes in the western USA. The Sacramento Speckled Dace, however, may have been a rather late addition to this fauna, which would explain its close genetic relationship with Klamath Speckled Dace. Genetics/genomics. The Sacramento Speckled Dace is one of three lineages, defined by genomics, that make up the Western Speckled Dace, Rhinichthys klamathensis (Smith et al. 2017; Su et al. 2022). The three lineages are also supported by Wiesenfeld et al. (2017) and Smith et al. (2017) using mtDNA and microsatellites. Etymology. The species name honors the Achomawi people (“river people”) whose historic homelands were along the Pit River and tributaries in northeastern California, from Goose Lake to Pit River Falls, and beyond (Dixon 1908). The Pit River is a branch of the Sacramento River that drains much of northeastern California. This region includes the Fall River system and Achjumawi Lava Springs State Park. The Speckled Dace is one of the most abundant native fishes in streams flowing through Achomawi lands. Alternate spellings include Achjumawi and Achumawi (Dixon 1908). The scientific names have a confusing history, starting with Jordan and Evermann (1896), who did not mention by name Speckled Dace in the Sacramento or Klamath rivers. They did include Sacramento Speckled Dace, vaguely from California, within Agosia nubila carringtoni. This taxon was first described in 1876 as Apocope carringtoni from Utah. Jordan and Evermann (1896) basically used this taxon to include miscellaneous Great Basin populations, and provisionally fish from the Lahontan Basin, as well as from various localities in southern and central California. “These California and Nevada forms may be distinct species, but if so, we are unable to define them (Jordan and Evermann 1896:312).” Snyder (1908) followed Jordan and Evermann (1896) in using A. n. carringtoni for a grab-bag of Speckled Dace from Oregon and California. By default, carringtoni became the species epithet for Sacramento Speckled Dace as Agosia carringtoni (Snyder 1913, 1917) and Rhinichthys osculus carringtoni (Shapovalov and Dill 1950, Kimsey and Fisk 1960). Moyle (1976, 2002) did not provide a name for Sacramento populations. See Table 1 for other synonyms. Conservation Status. The Sacramento Speckled Dace is widespread and abundant in the Sacramento River and tributaries, the Pit River system, Pajaro-Salinas watershed, San Luis Obispo Creek, and the Santa Maria River. It seems to have been extirpated from the San Joaquin River and tributaries although old records are scarce. The Speckled Dace is also absent from streams tributary to the San Francisco Estuary, including the Guadalupe River and tributaries, Coyote Creek, and Alameda Creek, for which there are historic records (Leidy 2007, R.L. Leidy, pers. comm. 2021). The dace was extirpated from Coyote Creek in the 1970s (Scoppettone and Smith 1976; J.J. Smith, pers. comm. 2021) and from Alameda Creek in the early 1900s (R. Leidy, pers. com. 2021). It has been extirpated from the Pajaro River, which flows into Monterey Bay, although it is still found in the upper and middle reaches of the San Benito River, a tributary to the Pajaro (J. J. Smith, pers. comm. 2021). The historic records, though few, indicate that the Speckled Dace was extirpated from these watersheds as the result of dams, habitat change, and diversions of water, coupled with severe drought.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 529-531, DOI: 10.11646/zootaxa.5249.5.1, http://zenodo.org/record/770135
Rhinichthys klamathensis subsp. goyatoka Moyle & Buckmaster & Su 2023, new subspecies
No full textRhinichthys 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).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 531-532, DOI: 10.11646/zootaxa.5249.5.1, http://zenodo.org/record/770135
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
Rhinichthys gabrielino Moyle & Buckmaster & Su 2023, new species
No full textRhinichthys gabrielino, new species, Santa Ana Speckled Dace Figs. 3, 4a, 5 Synonymy. Agosia nubila carringtoni Jordan and Evermann 1896:312; Culver and Hubbs 1917:82; Rhinichthys osculus carringtoni Shapovalov and Dill 1950:386; Shapovalov, Dill, and Cordone 1959; Kimsey and Fisk 1960:469; Cornelius 1969:1; Oakey et al. 2004:212; R. osculus subsp. widely used in California since the 1950s (for example: Moyle 2002, Moyle et al. 2015). Holotype. WFB 3498 (Fig. 4a), 73 mm SL, East Fork San Gabriel River, South of Upper Monroe Road, Angeles National Forest, Los Angeles County, California, 34 14’ 15.85”N 117 49’ 14.58”W, USA, 2 July 2021, J. Pareti (California Department of Fish and Wildlife). Paratypes. WFB 3499–3500, WFB 3501–3507 (n =9). Same data as holotype. Meristics: holotype (paratypes): Lengths(mm): standard 73(45–78), fork 82 (54–84), total 89 (57–90) Lateral line scales: 73(69–75). Lateral line complete on all fish, although there were 1–3 scale rows beyond the end of the lateral line (counted). Scales above lateral line 13(12–14). Scales below lateral line (10 (8–11) Dorsal-fin rays 7(7) Anal-fin rays 6(6) Pectoral-fin rays 11 (10–12) Pelvic 6 (6–7) Caudal-fin rays 19(19), 10 upper rays, 9 lower rays Diagnosis. Separated from all other Speckled Dace by the absence of supraorbital bones (vs. present, Smith et al. 2017). A cryptic species otherwise not distinguishable from other species/subspecies of the Speckled Dace complex except through genomics and geography. Slightly higher lateral line scale counts (mean 74, mode 76, range 64–82) than Sacramento Speckled Dace (mean 70, mode 72, range 54–82) and Lahontan Speckled Dace (mean 68, mode 72, range 60–77) (Table 2). Description. A cryptic species, as shown by genomic analyses; endemic to streams of Los Angeles, San Gabriel, and Santa Ana watersheds in southern California. Recognizable by typical stocky morphology of all Rhinichthys species; small size (adults 6–11 cm SL), wide caudal peduncle (about 1/3 the body depth), blunt-pointed snout, and subterminal mouth. Meristics overlap all other Speckled Dace taxa (Table 2). Body color variable, but adult fish usually pale yellow/white to dusky olive, often with small black spots. Head stripe and lateral spots/blotches pale or absent. Breeding adults of both sexes with orange to red fins; males also with red snouts and lips (Fig. 5). Lateral line usually complete, although last 1–10 scales may lack pores. High overlap in meristic counts with other California Speckled Dace populations (Table 2, Cornelius 1969). Morphometrics. Cornelius (1969) compared the body and fin morphology of 491 dace using 23 truss measurements (divided by standard length or head length, with all values converted to natural logarithms). Only small differences were found between Santa Ana Speckled Dace and dace taxa from other areas. His analysis showed that Santa Ana Speckled Dace had slightly longer fins, more anterior dorsal fins, somewhat longer and narrower heads, smaller eyes, and shorter upper jaws than dace from Sacramento, Lahontan, and Colorado river basins. All differences were not statistically different. However, morphometric differences were sufficient to distinguish lineages when combined meristic measurements and measures of jaw structure (below). Thus, Santa Ana Speckled Dace could be distinguished statistically from nearby Sacramento Basin populations and from Speckled Dace from Lake Tahoe (Lahontan Basin), although overlapping morphometrics made it difficult to assign individuals to any one taxon. Cornelius (1969:26) found that mouth structure provided the strongest separation of the taxa; he used a unique measure of jaw angle: “The lateral angle of the upper jaw formed by the premaxillary and maxillary as measured from photographs of the left side of the head.” Presumably a larger jaw angle is a measure of increased gape and size of prey. Cornelius (1969) found that Santa Ana Speckled Dace had a mean jaw angle of 145 degrees (n = 34, range 128–148) while the Sacramento dace had a mean jaw angle of 160 degrees (n=44, range 146–172). He also found that a frenum is fully developed in 54% (n=277) of the Santa Ana Speckled Dace but in only 2% (n =180) of Sacramento dace. Most (8 of 11 fish examined) Colorado Basin fish had a well-developed frenum. It was absent from (n=41) in Lahontan (Lake Tahoe) dace. Maxillary barbels were present on one or both sides of the mouth in all four dace populations compared, but they were variable in number and size so not useful for distinguishing Santa Ana Speckled Dace. Overall, Cornelius (1969) found that jaw angle, combined with other less quantitative features of the jaw, supported his finding that the Santa Ana Speckled Dace was distinct from dace from Lahontan and Sacramento basins. In combination with other features, jaw structure indicated that Santa Ana Speckled Dace had a common ancestry with fishes from the Colorado River watershed (Virgin River) (Cornelius 1969). This conclusion is supported by genetic and genomic studies (Smith et al. 2002, 2017, Su et al. in 2022). Genomics/Genetics. Genetic studies (mostly using mtDNA) generally indicate that the Santa Ana Speckled Dace is a sister lineage to Speckled Dace populations in the Colorado River Basin as result of a split in lineages approximately 3.6 million years ago (mya) (Oakey et al. 2004, Smith and Dowling 2008). Smith and Dowling (2008), using mtDNA well as morphometrics and meristics, indicate that populations of Speckled Dace in Los Angeles region streams have been isolated long enough (through the Pleistocene) to have diverged from one another and developed some small differences in morphological characters, supporting the findings of Cornelius (1969). The mtDNA analysis by Smith et al. (2017:77) showed “extreme molecular divergence” (about 7%) from other Speckled Dace populations, the highest they encountered. Oakey et al. (2004) also determined that Speckled Dace from the Santa Ana and San Gabriel rivers formed a distinct, monophyletic lineage. Su et al. (2022), using genomic data, confirmed that the Santa Ana Speckled Dace is a sister lineage to dace in the Colorado River Basin. In short, Santa Ana Speckled Dace are quite different genetically from Speckled Dace of other lineages in California and elsewhere (Smith et al. 2017, Su et al. 2022), supporting their designation as a full species (Figure 2). Distribution. Santa Ana Speckled Dace are endemic to three streams, and their tributaries, of the Los Angeles Region in southern California: the Los Angeles, San Gabriel, and Santa Ana rivers. In addition, the San Jacinto River is often treated as a separate river system. However, it historically flowed into the Santa Ana River, a connection severed by dams except in exceptionally wet years. The three river’s headwaters are in the Transverse Mountain Ranges, specifically the San Bernadino, San Gabriel, and Santa Ana mountains. The rivers flowed into an alluvial plain, now covered with Orange County development. During wet years, before the present era, this region would have flooded, connecting the Speckled Dace populations of the rivers. Today the scattered populations of Speckled Dace are largely confined to streams in a band of habitat on public lands that is below the high gradient upper regions of the three watersheds and above the developed alluvial plain. Santa Ana Speckled Dace are absent from many parts of their historic range (Moyle et al. 2015, O’Brien et al. 2011). Each population fragment is increasingly isolated from other populations as the result of dams and other modern infrastructure. Note: Biogeography. There is debate over exactly how the ancestors of Santa Ana Speckled Dace managed to move from the ancestral Colorado River basin to the Los Angeles region (Minckley et al. 1986; Spencer et al. 2008, Smith et al. 2017). They had to survive in a region with a dynamic geology to do so. To colonize coastal California, the dace would have had to travel several hundred kilometers overland (in the modern landscape) over an extended period of time. Speckled Dace in general are freshwater dispersers (Moyle and Cech 2004) so cannot move though marine environments to colonize new areas (Moyle 2002). The dispersal route also has to accommodate two sympatric freshwater dispersers, Santa Ana Sucker (Pantosteus santaanae) and Arroyo Chub (Gila orcutti), both which share ancestry with fishes in the Colorado Basin (Unmack et al. 2014). Smith et al. (2017) argue the fish were able to gradually make their way to California via successive stream captures in a geologically active landscape. This allowed fish to move between headwaters, eventually reaching streams that flowed into the Pacific Ocean from the Coast Range (Santa Monica Mountains). The exact route has been largely erased by the active geology. In contrast, Spencer et al. (2008) present evidence that a likely route was through a combination of two dispersal methods: movement of a plate carrying the fishes followed by colonization via headwater capture. It is likely that dace and other fishes were ultimately moved into the vicinity of the coastal drainages through a combination of the methods proposed by Smith et al. (2017) in concert with the periodic shifting of the main channel of the Lower Colorado River. This channel migration was a dynamic process driven by sediment deposition in the Colorado River channels. Fish presumably followed the river into new channels, including those adjacent to the proto-Santa Ana River and other coastal drainages. The channel migrations eventually blocked the Colorado River, diverting its flow into a large Pleistocene/Holocene lake basin (Lake Cahuilla) subsequent to the formation of the Salton Trough (ca. 1.3 mya). This lake, a predecessor of the Salton Sea, was colonized by lower Colorado River fishes. Bones of the larger fish species have been found in middens of fishing villages along Lake Cahuilla (Wilke 1980). Today, the Lower Colorado River and the Salton Trough are separated from the Santa Ana Basin by the 8–km-high San Jacinto and San Gorgonio Ranges. These ranges are parts of the Peninsula Range and were likely formed by complex plate movements associated with the development a bend in the San Andreas Fault System (ca. 1.1–1.5 mya) (Spencer et al. 2008, Fattaruso et al. 2016). The geologic movements transformed low-relief upland habitat into the dramatic landscape of today. The uplift of the ranges is associated with their westward tilting, resulting in the progressive capture and redirection of eastward-flowing tributaries at a rate of 20–44 km /my (Dorsey and Roering 2006), presumably with the fish. The rapid vertical motions driving these events were dramatic – sometimes exceeding 10m at one time (McClay and Bonora 2001). The suddenness of this redirection of western Colorado River tributaries into coastal-draining basins likely allowed the transfer of freshwater-dispersing fishes into the basin. These fishes apparently became completely isolated no later than ~1.1 mya (Fattaruso et al. 2016, Smith et al. 2017) when uplift of the mountains and downfaulting of the trough created an insurmountable barrier to further dispersal. The uplift the in the Peninsula Ranges (about 1.1–1.5 mya, Fattaruso et al. 2016) created a formidable barrier to freshwater fish dispersal and can be treated as the last point in time that dace could have colonized coastal waters. It is possible that dace were isolated slightly before the San Andreas fault began to shift, as suggested by previous studies (i.e. Spencer et al. 2008), but it is highly unlikely that isolation occurred subsequent to onset of the formation of the Salton Sink (ca. 1.1–1.3 mya) Note: Taxonomy. This study confirms that Santa Ana Speckled Dace is a full species, using the following lines of evidence. Taxonomy: While lacking formal description until now, the Santa Ana Speckled Dace has long been recognized as distinct (Swift et al 1993, Moyle 1976, 2002, Oakey et al. 2004). Definitive morphometric and meristic characters are largely absent. However, when combined, they can be used to distinguish Santa Ana Speckled Dace statistically from populations of other Speckled Dace species/subspecies, as well as from Colorado River Speckled Dace, indicating their long isolation (Cornelius 1969). The apparently unique feature of complete absence of supraorbital bones further supports the species status of this dace. Geology: Improved understanding of the dynamic geology of southern California and of the shifting channels of the Colorado River have resulted in more supportable hypotheses as to how Speckled Dace and other endemic fishes were able to colonize coastal southern California streams. Zoogeography: The historic distribution of the species in streams of the Los Angeles region shows long separation from their ancestral population and long isolation without access to other populations that could lead to hybridization. Although Smith et al. (2017) regard hybridization as the reason R. osculus is just one species throughout its enormous range, including the Los Angeles region, hybridization has clearly not been an issue with the Santa Ana Speckled Dace, which has had no opportunities for over 1.3 million years. Genomics/genetics. Su et al. (2022) show that the Santa Ana Speckled Dace is the most distinct genetically of all other dace populations in California, indicating a long history without gene flow from other dace populations. Etymology. The species epithet honors the Gabrielino-Tongva people, the indigenous inhabitants of the region at the time of the Spanish invasion and who still have a significant presence (https://gabrielinotribe.org/). The original range of the Santa Ana Speckled Dace was in the streams that flowed through the band’s homeland. The tribe is also known as San Gabriel Band of Mission Indians. The common name, Santa Ana Speckled Dace, is widely used for this fish (e.g. Moyle 2002); it shares its name with the Santa Ana Sucker which also occurs in the Santa Ana River and adjacent watersheds. Note: nomenclature. The scientific name has long been a source of confusion. Jordan and Evermann (1896:312) list Agosia nubila carringtoni as having a wide distribution in the Great Basin but state “To this form we also refer provisionally specimens from Lake Tahoe and elsewhere in the Lahontan basin but also those from various coastwise localities in central and southern California, where it is abundant in clear streams and springs as far south as San Luis Obispo.” Agosia n. carringtoni consequently was applied by early workers (e.g., Snyder 1918) to most dace populations in central and southern California including in the first paper mentioning Speckled Dace in the Los Angeles region (Culver and Hubbs 1917). Cornelius (1969:18) summarized the history of the use of carringtoni and quoted a personal communication from Carl Hubbs that there was “no sound basis for continued use of carringtoni in reference to Santa Ana Speckled Dace.” Despite this comment, Cornelius (1969) concluded that R. osculus carringtoni was the only available scientific name. Nevertheless, carringtoni reverted, with no real discussion, to being the name for Speckled Dace found in the Bonneville basin of Utah and Idaho (Smith et al. 2017) from whence it was originally described (Cope 1872). The Santa Ana Speckled Dace has subsequently been referred to as just R. osculus (e.g. Swift et al. 1993, Moyle 1976, 2002) or R. osculus subsp. (e.g., Moyle and Davis 2000, Moyle et al. 2015, Smith et al. 2017) but has resisted formal description until now. Conservation Status. In California, Santa Ana Speckled Dace historically inhabited streams in the upland areas of the San Jacinto, Santa Ana, San Gabriel and Los Angeles rivers which were interconnected by lowelevation floodplains (Swift et al. 1993, Moyle 2002, Moyle et al. 2015) (Figure 5). They have since disappeared from much (75%) of their range, including the middle reaches and tributaries of the Santa Ana River, most of the Los Angeles River and San Jacinto River basins (Moyle et al. 2015, Center for Biological Diversity 2020). Their current distribution is restricted to headwater streams of the San Jacinto, Santa Ana, and San Gabriel rivers and Big Tujunga Creek (Los Angeles River drainage). In 2005, Speckled Dace were reintroduced into the North Fork of Lytle Creek; a similar introduction was made into the Middle Fork in 2007 (Moyle et al. 2015). Both were apparently successful.Attempts to establish populations of Santa Ana Speckled Dace outside their native range were made through introductions into the Santa Clara and Cuyama rivers. Success of these populations is uncertain. An additional introduction into River Springs, Mono County, failed The third edition of the Fish Species of Special Concern Report of the California Department of Fish and Wildlife (Moyle et al. 2015) rates the Santa Ana Speckled Dace as one of the most endangered fish in California. The report notes that the Santa Ana Speckled Dace is a U.S. Forest Service Sensitive Species in the three national forests in which it is found (Angeles, San Bernardino, Cleveland NFs). However, it is likely extirpated from Cleveland National Forest (Santiago Creek). The California Natural Diversity Database ranks Speckled Dace as secure at the global scale (G5) but the Santa Ana subspecies as Imperiled (T1S1; www.natureserve.org). It is listed as Threatened by the American Fisheries Society (Jelks et al. 2008). The habitat of this species continues to shrink due to urbanization of the Los Angeles region, resulting in fragmentation and reduction of populations. Intense human use of their streams on public lands for recreation and water supply also contributes to their decline. Extinction seems likely in the next few decades without special protection for all remaining populations (Swift et al. 1993, Moyle 2002, Moyle et al. 2015). Listing Santa Ana Speckled Dace as threatened or endangered under state and federal Endangered Species Acts would be a major step towards preventing extinction. It appears that lack of a formal species description has been a barrier to listing, even though recent genetic and phylogenetic studies show it to be distinct from all other Speckled Dace (Oakey et al. 2004; Smith and Dowling 2008, Mussmann 2018, Su et al. in 2022). It could therefore be listed as a Distinct Population Segment, even without formal description. Our paper resolves whatever taxonomic uncertainty previously confounded action by regulatory authorities.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 509-517, DOI: 10.11646/zootaxa.5249.5.1, http://zenodo.org/record/770135
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The vanishing author in computer-generated works: a critical analysis of recent Australian case law
No full textAbstract
The use of software is ubiquitous in the creation of many copyright works, yet the requirement in copyright law that every work have a human author who engages in independent intellectual effort means that its use may prevent copyright subsistence. Several recent Australian cases have refocused attention on authorship as an essential criterion of copyright subsistence, and these cases suggest that much computer-produced output may be authorless and thus lack copyright protection. This article, the first in a two-part series, analyses how each case deals with the question of authorship of computer-produced works and why the use of software diminishes copyright protection for a significant number of computer-generated works. The article critiques the application of conventional notions of human authorship developed in the pre-computer age to modern productions and suggests alternative approaches to authorship that satisfy both the major objectives of copyright policy and the need to adapt to the computer age. The article argues that, without a broader judicial approach to authorship of computer-generated works, Parliament must remedy the lacuna in protection for these ‘authorless’ works. Possible solutions for reform are suggested. In a forthcoming article, the author comprehensively examines those reform proposals
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Dissipative Range Scaling of Higher Order Structure Functions for Velocity and Passive Scalars
No full textDifferently to Kolmogorov's second similarity hypothesis, we find that the 2n-th order velocity and scalar structure functions scale with n-th order moment of the energy dissipation and the scalar dissipation, respectively. The origins of this scaling are analyzed by the transport equations of the fourth order velocity and scalar increment moments and by direct numerical simulations
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