Catostomus murivallis Harris, Markle & Campbell 2025, new species

Catostomus murivallis Harris, Markle & Campbell, new species urn:lsid:zoobank.org:act: A670A9F7-6C4A-422F-A3E5-24F2CD5A9641 Wall Canyon Sucker (Figures 2 and 3) Catostomus sp. — Hubbs and Miller, 1948:64 (Wall Canyon endemic). Moyle, 1976:213 (“an undescribed sucker lives in Wall Canyon Creek...”). Williams et al. 1985:9 (list of fishes of concern from North American deserts). Williams et al. 1989:6 (list of endangered, threatened, or of special concern fishes of North America). Miller, Hubbs, and Miller, 1991:26 (“new taxa collected”). La Rivers, 1994:6 d (revised list of Nevada fishes). Smith et al., 2002:216 (“relict sucker of Wall Canyon”). Bagley et al. 2018:8 (“ Catostomus sp. Wall Canyon”). Campbell et al. 2023:273 (“Wall Canyon Sucker Catostomus sp. ”). Holotype. OS 17570, a gravid female, 213.9 mm SL, from Wall Canyon Creek, Surprise Valley, Washoe Co., Nevada (latitude 41.265983 N, longitude 119.73233 W), 25 May 2001, B. Nielsen, S. Reid, and D. Markle Paratypes. OS 15769, 3 (70.3–202.0 mm SL); LACM 25189, 12 (66.5–119.9 mm SL); LACM 25190, 4 (94.6– 127.4 mm SL); LACM 25192, 10 (62.3–122.7 mm SL); UMMZ 130543, 27 (64.1–131.1 mm SL). Additional material. OS 13908, 8 (119.0– 157.8 mm SL); OS 13909, 1 (248.37 mm SL); OS 14101, 4 (103.5– 136.8 mm SL); OS 104101, 18 (96.5–143.6 mm SL); UMMZ 130453, 2 (86.3– 95.9 mm SL); UMMZ 181729, 29 (54.2–85.2 mm SL). Diagnosis. A species of Catostomus (sensu stricto) restricted to Wall Canyon Creek, Surprise Valley, Washoe Co., Nevada. It is distinguished from Ca. warnerensis and Ca. fumeiventris by the following traits: moderately coarse scales, 67–92 usually in the lateral line, modally 85 (vs. modally 74 in Ca. warnerensis [range = 64–85]; modally 73 in Ca. fumeiventris [66–86]); scale rows between dorsal-fin origin and lateral line 12–17, modally 15 (vs. 14 [11–17]; 13 [12–16]); snout length 6.8–12.6% SL, mean 10.1% (vs. 9.7–12.3%, mean 10.6%; 9.3–12.6%, mean 10.9%); body depth 16.7–24.1% SL, mean 20.9% (vs. 16.8–28.4% SL, mean 22.25; 18.6–27.3% SL, mean 21.7%); caudal-peduncle depth 8.0–12.1% SL, mean 9.5% (vs. 8.3–11.7% SL, mean 10.0; 7.3–11.6% SL, mean 9.75); dorsal-fin base 11.2–16.7% SL, mean 14.0% (vs. 12.3–18.6%, mean 15.6%; 11.9–17.8%, mean 14.6%); dorsal-fin origin to pelvic-fin origin 17.2–25.7% SL, mean 21.2% (vs. 18.3–28.3%, mean 22.6%; 19.7–26.3%, mean 22.4%); dorsal-fin origin to anal-fin origin 28.6–39.1% SL, mean 33.2% (vs. 32.7–42.0% SL, mean 35.3%; 30.8–38.6% SL, mean 35.9%); dorsal-fin insertion to anal-fin origin 17.5–25.4% SL, mean 21.7% (vs. 18.5–26.7% SL, mean 22.6%; 18.6–26.1% SL, mean 22.85); eye to nare 1.3–4.4% SL, mean 3.1% (vs. 2.3–4.1%, mean 3.3%; 2.5–5.1%, mean 3.6%); upper-lip 4.3–7.7% SL, mean 5.8% (vs. 4.1–7.9%, mean 5.3%; 4.1–7.8%, mean 5.6%). Description. Morphometric data are given in Table 1, and scale-count characters appear in Tables 2 and 3. Body form and pigmentary characters are shown in Figure 2. The body is terete, with other aspects of general appearance resembling those of other western North American Catostomus species. Nuptial individuals of both sexes have a red lateral stripe. Color in preservative, dark brown above, pale tan to yellow below. Fin-rays generally darkly pigmented in all fins, fin membranes unpigmented. The mouth is horizontal and inferior; upper lip 4.3–7.7% SL, lower lip 3.5–5.6% SL. Lips small, the lower lobes incompletely cleft, with a space of one or two intervening papillae, but closely appressed at the midline (Figure 3). Upper lip with three rows of round papillae crossing the midline; lower lip with nine or fewer rows of round to rectangularly-shaped papillae crossing a longitudinal line on longest part of lower lobes. Frontoparietal fontanelle well developed. Based on eight specimens (OS 13908), gill-rakers on first arch 23–30, gill-teeth on back of first arch 33–35 (N=4), vertebrae anterior to dorsal origin 14–15 (N=7) and anterior to anal origin 29–30 (N=8), precaudal vertebrae 24–25 (N=8), caudal vertebrae 15–17 (N=8), total vertebrae 39–41 (N=8). Etymology. Muri from the Latin murus for wall, and vallis for valley; the specific epithet is treated as a noun in apposition. Specific and common names refer to the distribution of this species, which is Wall Canyon, in Surprise Valley, NV. Range. Restricted to Wall Canyon Creek in Surprise Valley, Washoe Co., Nevada. Comparisons. Among morphometric characters meeting statistical assumptions for ANOVA, 16 of 34 and 17 of 34 characters differed significantly between the Wall Canyon Sucker and Ca. warnerensis and Ca. fumeiventris, respectively (Table 1). Nineteen of 34 morphometric characters were significantly different between Ca. warnerensis and Ca. fumeiventris (Table 1). Three of four and two of four meristic characters differed significantly between the Wall Canyon Sucker and Ca. warnerensis and Ca. fumeiventris, respectively (Tables 2 & 3). All four meristic characters were significantly different between Ca. warnerensis and Ca. fumeiventris (Tables 2 & 3). Body form and coloration of Ca. murivallis are most similar to Ca. warnerensis, with the abdomen of both species being creamy white; a red lateral stripe is displayed by nuptial individuals of both sexes. In contrast, Ca. fumeiventris has a dusky abdomen and lacks the red lateral stripe (Miller, 1973). The lips of Ca. murivallis are small, although both lips are proportionally longer than those of Ca. warnerensis and Ca. fumeiventris (Table 1). Upper lip papillae of Ca. murivallis are round, resembling those of Ca. fumeiventris; whereas the upper lip papillae of Ca. warnerensis are oblong in appearance. Papillae on the lower lip of Ca. murivallis are round anteriorly, becoming more rectangular posteriorly; lower lip papillae of Ca. warnerensis are generally round, while appearing more oblong on Ca. fumeiventris (Figure 3). All three species have a well-developed frontoparietal fontanelle. Of the two other geographically proximate Catostomus species, this condition is shared with the Tahoe Sucker (Ca. tahoensis) but contrasts with the Modoc Sucker (Ca. microps), which has a partially or fully closed fontanelle (Moyle, 1976; Smith, 1992). Catostomus tahoensis differs from Ca. murivallis in having finer scales (82–95 lateral line scales vs. 67–92), a larger mouth with larger papillae, and a thicker caudal peduncle (Moyle, 1976). In addition, combined mtDNA cytochrome b and NADH2 gene sequence data (Bagley et al. 2018) indicates pair-wise sequence divergence between Ca. tahoensis and Ca. microps versus Ca. murivallis as 15.1% and 14.7%, respectively. By comparison, Ca. fumeiventris differs from Ca. murivallis and Ca. warnerensis by 8.2 and 7.7%, respectively; whereas Ca. murivallis and Ca. warnerensis differ by 1.1%. The fossil Miocene and Pliocene sucker of the Snake River Plain and Pliocene Honey Lake, † Ca. shoshonensis, shares a diagnostic maxilla shape with Ca. murivallis according to Smith et al. (2002). They also noted that hydrographic cycles in the Great Basin should have led to many opportunities for allopatric speciation, but that desiccation cycles have apparently been so severe that extinction has dominated. If the Ca. murivallis-Ca. warnerensis clade has persisted since the Miocene, the relatively low sequence divergence suggests that only a more recent allopatric event can be detected. This is reflected in molecular differentiation and molecular phylogenetic divergence time estimation (Supplemental Figure S1) that indicates a divergence during the Pleistocene.