|
<br />Species Account - Catostomus commersoni
<br />
<br />
<br />Fig. 35. Catostomus commersoni adult (@ Joseph R.
<br />Tomelleri).
<br />
<br />Adult Description: Back without conspicuous predorsal keel.
<br />Robust. Caudal peduncle depth about 6.5-8.6% TL. Inferior,
<br />slightly overhung mouth; no hard, prominent, cartilaginous
<br />ridges along inside of jaws. Lips relatively small, papillose,
<br />without notches at comers; lower lip wider than long with a
<br />deep median cleft, usually without rows of papillae (some-
<br />times I or 2) spanning the two lobes. Dorsal fin not large and
<br />falcate. Scales large. Gill rakers relatively few, somewhat
<br />knobbed. Peritoneum pale or lightly speckled. TL usually 30-
<br />50 cm, up to 64 cm. (Also, Table II.)
<br />
<br />Reproduction: Non-guarding, open-substrate lithophil.
<br />April or May to August, 7-190C, usually >lOoC; mostly
<br />June to mid-July in the Upper Colorado River Basin.
<br />Frequently in large aggregations migrate to streams or lake
<br />shores to spawn in shallow water, usually <0.3 m, and
<br />moderate currents, mostly 30-49 cm/sec, over sand or
<br />gravel; often over riffies in streams. Water-hardened eggs
<br />2.6-3.3 mm diameter, demersal, initially adhesive.
<br />
<br />Young: Hatchin5-11 days at 18-lOoC, remain in gravel 1-
<br />2 weeks, drift as late protolarvae and mesolarvae, usually at
<br />night, and subsequently occupy low velocity shoreline areas,
<br />often over sand and gravel or in aquatic vegetation.
<br />
<br />
<br />J
<br />
<br />:-.-.-._._.~._._.-._.
<br />"
<br />"'
<br />.,
<br />
<br />Fig. 36. Recent distribution of Catostomus commersoni
<br />in Colorado River Basin.
<br />
<br />Table 11. Selected juvenile and adult meristics for Catostomus commersoni. P = principal rays; R = rudimentary rays; D = dorsal; V =
<br />ventral. Scales are lateral series or line when complete. Four added to vertebral count for Weberian complex. Gill rakers for exterior row of
<br />fut arch, specimens> 70 mm SL. Mean or modal values underlined ifknown and noteworthy; rare or questionable extremes in parentheses.
<br />
<br />Character Original Literature Character Original
<br />Dorsal Fin Rays - P: 10-11-12(13) (9)10-13(-15) Dorsal Fin Rays - R: 2-1-4(5)
<br />Anal Fin Rays - P: (5-)7(8) (6)1-8 Anal Fin Rays - R: 2-1
<br />Caudal Fin Rays - P: 18 18 Caudal Fin Rays - RD: 1O-11-13
<br />Pectoral Fin Rays: 13-1.2.-16(17) 13-19 Caudal Fin Rays - RV: ~-1O
<br />Pelvic Fin Rays: 8-lQ 9-11 Lateral Scales: 56-59-68-72
<br />Vertebrae: 45-46-48 44-48 Gill Rakers:
<br />
<br />Literature
<br />
<br />53-56-70-76(-85)
<br />20-27
<br />
<br />Table 12. Size at apparent onset of selected developmental events for Catostomus commersoni, as observed under low power
<br />magnification. P = principal rays; R = rudimentary rays. Scales are lateral series. Rare or questionable extremes in parentheses.
<br />
<br />Event or Onset or Formation Fin Rays First Formed Last Formed
<br />Structure mm SL mm TL or Scales mm SL mm TL mm SL mm TL
<br />
<br />Hatched: (7)8-10 8-10 Dorsal- P: 12-14(15) 14-15(16) 14-16 16-17
<br />Eyes Pigmented: (7)8 or * 8 or * Anal- P: 14-16 16-17 15-16(17) 18-19(20)
<br />Yolk Assimilated: 10-12(-14) (10)11-13(-15) Caudal - P: 10-12(13) 10-13 (12)13-15 (13)14-16
<br />Finfold Absorbed: (17-)19-20 (21-)23-24 Caudal - R: 13-15 14-16 (17) 18 (21 )22-23
<br />Pectoral Fin Buds: (7)8 or * 8 or * Pectoral: 14-16 16-17 16(-20) 19(-24)
<br />Pelvic Fin Buds: 13-15 (14)15-16 Pelvic: 15-16 18-19 16-18 19-22
<br />* before hatching Scales: 22(23 ) 27 29-31 36-37
<br />
<br />References: Auer 1982, Baxter and Simon 1970, Baxter and Stone 1995, Beckman 1952, Carlander 1969, Carlson et al. 1979, Ellis
<br />1914, Fuiman 1979, Fuiman and Trojnar 1980, Geen et al. 1966, Hubbs et al. 1943, Jones et al. 1978, Jordan and Evermann 1896,
<br />Lee et al. 1980, Lippson and Moran 1974, Miller 1952, Minckley 1973, Prewitt 1977, Reighard 1920, Scott and Crossman 1973,
<br />Smith 1985, Stewart 1926, Sublette et al. 1990, Twomey et al. 1984, Wheeler 1997, Woodling 1985.
<br />
<br />44
<br />
|