SUCKERS OF UTAH LAKE

A. GAYLON COOK

BIOCONSERVATION INTERNATIONAL 3306 N CANYON RD PROVO UT 84604-4548

Running Head: SUCKERS OF UTAH LAKE SUCKERS OF UTAH LAKE

A. Gaylon Cook'

ABSTRACT.— There has been much confusion about which suckers exist in Utah Lake, and even about the number of species present. Considerable misunderstanding has resulted from an incomplete exploration of the literature on catostomid morphology and taxonomy. Numerous descriptions of Utah Lake suckers have been recorded, but none has included all or close to all of the taxonomic characterizations that are now available. Herein, those descriptions are organized, collated, and discriminatingly analyzed so that different catostomids are defined and delimited as completely as possible. This paper establishes a basis for needed chemical taxonomic analyses such as DNA-DNA hybridization tests. Also, its detailed descriptions constitute a resource that can be used for such purposes as distinguishing taxa in periodic ichthyological surveys of Utah Lake or identifying suckers during recovery-plan activities on an endangered species.

Key Words: catostomids, suckers, Utah Lake, taxonomy, systematics, endangered species, ichthyofauna

Utah Lake, closely bordered by the city of Provo, is a 38,800-ha body of fresh water (Carter 1969: 2) in central Utah measuring 23.5 by 38.0 km (Radant and Sakaguchi 198 lb: derived from Fig. 1). This lake has a mean depth of 2.9 m and a maximal depth of 4.2 m (Radant and Sakaguchi 1981b: 2). It drains >6700 km2 of land (Carter 1969: 3-4) and formerly collected a flow of 740 million m3/yr (Arnold 1960: 11-17).

Ignorance of the ichthyological literature and misperceptions about what it has established, have resulted in inaccurate nomenclatures and misinterpreted taxonomic relationships. Nescience about the phylogenetic relationships of Utah Lake catostomids is underscored by a dispute about the number of species present. Significantly, it is not known whether certain taxa constitute endemic species or subspecies that may be worthy of endangered status. The principal aim of this review is to establish a sound basis for defining and delimiting as precisely as possible the catostomids of Utah Lake. Species descriptions are compared in detail. It is hoped that this paper will lay the groundwork for further systematic investigations. Taxonomic studies employing DNA-DNA hybridization analyses, as well as those that might utilize biochemistry,

'Bioconservation International, Provo, Utah 84604-4548. GREAT BASIN NATURALIST 2 immunology, serology, protein sequencing, or comparative anatomy, need to be performed on Utah Lake suckers. Besides being quick, DNA hybridization offers the most precise quantitative comparisons (Sibley and Alquist 1990: 3). It is also anticipated that the characterizations that are presented here will assist ichthyologists in identifying Utah Lake catostomids. For example, descriptive data can be used by fishery biologists with the Utah Department of Natural Resources, Division of Wildlife Resources in their effort to identify endangered adult June Suckers (Chasmistes liorus), and distinguish them from 3 other catostomids during spawning-season sampling and reproductive facilitation in lower Provo River. Suckers are frequently misidentified by these biologists during reproductive surveys that are performed as a part of the June Sucker recovery plan (Charles W. Thompson, personal communication). The comparative temporal incidence of the catostomids of Utah Lake will be treated in a future paper.

DESCRIPTIONS OF TAXA r Exceptional Sucker Catostomus generosus (exceptional low-mouth: Greek kato, low; stoma, mouth; Latin generosus, superior or exceptional) / Mountain Sucker Catostomus platyrhynchus (broad-snouted low-mouth: Latin platy, broad; Greek rhunkhos, snout or bill). Synonyms of these species are Acomus generosus (Girard 1857a, 1858: 221-222), Catostomus (Acomus) generosus (Girard 1857b: 174),

Catostomus generosus (taken at Utah Lake) (Cope 1872), Minomus platyrhynchus, M. jarrovii, and C. ? generosus (all 3 collected about Provo, Utah) (Cope 1876), and Pantosteus platyrhynchus and P. jarrovii

(Cope and Yarrow 1876: 673-675). Neither C. generosus nor the 1.1-kg C. ? generosus was described. To be able to confirm that they resemble A. generosus more than M. platyrhynchus or M. jarrovii, sound examples of the 2 generosus forms must persist, allowing their comparison with descriptions of the other forms, and any remaining intact exemplars of A. generosus and M. platyrhynchus (apparently no examples of M. jarrovii persist; see below). After comparing multiple specimens of each form, Jordan (1878a, b:

183-184) deemed Pantosteus (= Acomus = Catostomus) generosus equal to P. jarrovii, but the remarkably slender (allegedly due to flabbiness) P. platyrhynchus a separate species. Jordan (1878b) reported that

P. generosus occurred in the "Rio Grande, Colorado Basin," and the "Great Basin of Utah". There was SUCKERS OF UTAH LAKE 3 actually no record of this species in Colorado. However, Cope and Yarrow (1876) had recorded collections of "P. jarrovii", a synonym of P. generosus, at 5 New Mexico localities. Perhaps, Jordan (1878b) considered the "Costilla, N. Mex" site, which existed on the New Mexico side of its border with Colorado, to be in the Colorado Basin. It is situated in San Luis Valley which lies principally in Colorado, and to an appreciable extent, in its Costilla County. Jordan (1878b) stated (see also Jordan and Gilbert [1882: 123]) that P. generosus and P. platyrhynchus were "very similar" but added, "...at present I consider (them) distinct." Later, Jordan (1886) proclaimed, "The type of Catostotnus generosus seems to me unquestionably identical with the type of" P. platyrhynchus and "with P. jarrovii". "The peculiarities of P. platyrhynchus seem to be due to its shriveled condition." Actually, 3 specimens (apparently syntypes) of A. generosus

(Girard 1858) and several syntypes of M. platyrhynchus (Cope 1876) had been collected. Jordan (1887b:

805) lumped all 3 forms within P. generosus. Jordan (1891) and Jordan and Evermann (1896a: 170-171) regarded Cope's (1876) M. jarrovii and M. platyrhynchus as synonyms of A. generosus (Girard 1857a,b,

1858) but Cope and Yarrow's (1876: 674-675) P. jarrovii from New Mexico as a synonym of Catostomus plebeius which had been taken at Mimbres River near the border of USA and Mexico (Baird and Girard

1856). Jordan (1887a) and Jordan and Evermann (1896b: 238, 1902: 45-46) also did not consider platyrhynchus or jarrovii to be full species. Jordan and Evermann (1896a: 170) gave an inaccurate and incomplete synopsis of "P. generosus". Snyder (1916) placed generosus in the genus Notolepidomyzon with plebeius and 2 other forms, and surmised that jarrovii, whose "cotypes" were missing, was a synonym of generosus because it was squatter than platyrhynchus, to which he synonymized Pantosteus jordani from the upper Missouri River Basin (Evermann 1894). Believing that Pantosteus (= Acomus) generosus might equal

Catostomus plebeius, Snyder (1922) speculated that the unit of Captain J. W. Gunnison and Lieutenant E. G.

Beckwith, who were searching for a potential railroad route to the Pacific Ocean, took the former from the

Rio Grande Basin of southern Colorado. Jordan et al. (1930: 104) assigned generosus and plebeius to the genus Notolepidomyzon, and platyrhynchus to Pantosteus, placing a question mark in front of the name of its synonym M. jarrovii from Provo, Utah, because "the type" (actually there were 2 syntypes) of GREAT BASIN NATURALIST 4

M. jarrovii (Cope 1876) had been lost. The synonymization of jarrovii with platyrhynchus was in error on the basis of previous examinations of specimens which indicated that jarrovii equaled generosus (see above).

Based on the geographic ranges in Moore's (1968: 101) species accounts, his Catostonws platyrhynchus included generosus and jarrovii (see also Robins et al. [1991]).

In an article rife with inaccuracies (e.g., the claim that specimens of Gila elegans and Algansea obesa were of unknown origin when in actuality, G. elegans had been collected at 5 different known sites including

Grand River, Utah, and A. obesa had been taken in Humboldt River [Baird and Girard 1854a, Girard 1857a, b: 183, 205, 1858: 239, 286-287]), Snyder (1922; "do" in his table means "ditto") indicated that 4 or 5 of the 6 piscine species that had been taken in 1853 or 1854 at Cottonwood Creek, "an affluent of the great

Salt Lake of Utah" (Girard 1857a, b: 174, 185-186, 197, 199, 1858: 21-22, 221-222, 243-244, 267,

271-272), were actually from the Mississippi River Basin. One of those 6 taxa was A. generosus.

Apparently, Snyder's (1922) skepticism about the origin of fishes that had been taken in "Cottonwood

Creek, Utah" was triggered by Jordan and Evermann's (1896a: 273) comment that the recorded collection site of Cyprinella gunnisoni (Girard 1857a, b: 197, 1858: 267-268; equals Leuciscus (= Notropis) bubalinus

[Baird and Girard 1854b] based on Jordan's [1886] statement that "The types of C. gunnisoni seem to be the young of N. bubalinus"; see also Jordan and Evermann [1896a: 273], Jordan et al. [1930: 130]) must be in error because Notropis spp. do not occur in Utah. Snyder (1922) reasoned that if any specimens (e.g., those of Notropis spp.) which were reported to have been taken from Cottonwood Creek, Utah were not actually collected there, none of them were. In accordance with the publication and comments of Snyder

(1922), a colleague and former student of Jordan's at Stanford University, Jordan et al. (1930: 130-131), without a sound evidential basis, proclaimed acquisitions of C. gunnisoni from "Cottonwood Creek of the

Rio Grande, Colo.", C. ludibunda (Girard 1857a, b: 199, 1858: 271-272; = Notropis ludibundus of Jordan and Evermann [1896a: 273] and contrary to priority, N. stramineus of Robins et al. [1991: 77]; see also

Jordan et al. [1930: 130]) from a "locality now known to be Cottonwood Creek, Colo.", and C. lugubris

(Girard 1857a,b, 1858; likely = N. macrostomus; see Jordan and Gilbert [1882: 177], Jordan and Evermann

[1896a: 274], Jordan et al. [1930: 131]) from "Cottonwood Creek, Colo." Snyder (1922) declared that SUCKERS OF UTAH LAKE 5

Lieutenant Beckwith's detachment was without a naturalist on 8 November (actually 7 November) 1853 when it camped at Cottonwood Creek, Utah so "it was quite probable that no collecting was done." However,

Snyder (1922) believed that Siboma atraria was taken at "Fish Springs", Utah after that naturalist's death.

Moreover, Snyder (1922) related that J. A. Snyder, the unit's assistant topographer, had "collected some specimens." Near the end of his report dated 31 January 1854, Beckwith (1854: 98) signified that a replacement(s) had been selected to describe biological collections, a work that had been delayed due to the slaughter of F. Creutzfeldt, the unit's botanist. Interestingly, Girard (1858: 221-222) stated, and Girard

(1857b: 174) implied, that A. generosus was taken at Cottonwood Creek, Utah by Beckwith. Apparently the collector of A. generosus, C. gunnisoni, and Argyreus dukis in that stream did not record the date of their collection, and Girard (1858: 221-222, 243-244, 267) wrongly assumed the year was 1854. Beckwith's

(1854: 129) detachment was in Salt Lake Valley from November 1853 to May 1854. The Cottonwood Creek where Beckwith's (1854: 128) unit camped was not the one lying at 41°10-15' N latitude, largely in the

Ogden, Utah area, but being located 18.4 km north of Salt Lake Valley's Willow Creek and 15.8 km south of Salt Lake City (in 1853), was either Little Cottonwood Creek or Big Cottonwood Creek. There is no reason to believe that this stream, one of the 4 recorded collection sites of the Gunnison/Beckwith party (the collection localities of some piscine specimens obtained by the unit were not recorded), was not authentic.

Those exemplars for which collection sites were registered, that Beckwith reportedly delivered to

Smithsonian Institution, were caught in Utah's Cottonwood Creek, a Utah spring "near the desert",

Colorado's Utah Creek, and a sluice in Arkansas River near Fort Makee (Girard 1857a, 1858: 21-22,

221-222, 234, 236-237, 243-244, 267-268, 271-272, 277-278, 297-298, 320-321). The exploratory party of

Gunnison and Beckwith probably did not actually collect the 3 taxa from the Arkansas River sluice that were delivered to Smithsonian Institution (2 of them were taken in 1853) because there was no report of the unit passing through Fort Makee on its westward expedition (Beckwith 1854); F. Creutzfeldt, who supposedly took Cyprinella beckwithi in 1854 (Girard 1858: 267-268), was killed in October 1853 (Beckwith 1854: 79-

82) (Girard [1857a] assumed that Creutzfeldt had acquired all specimens obtained by the Gunnison/Beckwith party). All other piscine examples collected from tributaries of Arkansas River in the 1850s were reportedly GREAT BASIN NATURALIST 6 taken by Dr. C. B. Kennerly, H. B. Mollhausen, and Dr. George G. Shumard serving under Lieutenant

A. W. Whipple (Girard 1857a, 18571): 166, 170, 178-179, 182, 189-191, 193, 198, 1858: 4-5, 14-17, 21-22,

25-26, 28-29, 96-98, 208-209, 211-212, 231, 234-237, 249-251, 256, 259-263, 266, 270, 275-276).

Snyder (1922) asserted that Cottonwood Creek, Utah "is... as is now evident, an impossible locality for the species which (Girard) assigned to it", and proclaimed that A. generosus was not really taken in

Bonneville Basin because other species reportedly collected in Cottonwood Creek actually inhabit Mississippi

Valley. Ironically, Snyder (1916) had earlier attested, "It is quite within reason to presume that

(Notolepidomyzon = Acomus) generosus is represented in the upper Columbia Basin." Even though Girard

(1857a, b: 174, 1858: 221-222) reported that A. generosus was collected in Cottonwood Creek, Utah, Snyder

(1922) did not ascribe a stream with that name as its provenance, but conjectured, "It now seems probable that the fishes called A. generosus were collected in the Rio Grande basin, perhaps in Utah Creek". Snyder's

(1922) justification for this opinion was the resemblance that he noticed between Catostomus plebeius from that basin and A. generosus. It is ironic that Snyder felt constrained to speculate on a non-Utah collection site for A. generosus when C. generosus, C. ? generosus, M. platyrhynchus, and M. jarrovii were all collected about Utah Lake (Cope 1872, 1876). Later, Snyder (Jordan et al. 1930: 104) stated that

A. generosus had been taken not in Utah's Cottonwood Creek but the one "no doubt from Colorado." In

Costilla County of southern Colorado, there is a Cottonwood Creek that closely parallels Utah Creek (W. A.

Nichols [1857], Map of the Department of New Mexico and Adjacent Territory) (= Ute Creek [C. Roeser

1879], State of Colorado [map], U.S. Department of the Interior, General Land Office) to its west. The

Gunnison/Beckwith party camped for several days at Utah Creek, but there is no record of any member of the unit going to Cottonwood Creek (Beckwith 1854: 38-41). Moreover, Girard (1858: 320-321), possibly using information on the specimen label of Salar virginalis, was fundamentally accurate in stating that Utah

Creek was a tributary of Rio Grande del Norte; if collections had been made in a neighboring stream, it is not unlikely that specimen labels would have noted that this waterway was also a tributary of the Rio

Grande. The adjacent Utah and Cottonwood Creeks are tributaries of Trinchera Creek (or River) which flows into northern Rio Grande River (see also U.S. Department of the Interior, Geological Survey [1973], SUCKERS OF UTAH LAKE 7

State of Colorado [map]). Cyprinella lugubris, C. ludibunda, and Bryttus (=Lepomis [Jordan and Gilbert

1882: 479]) humilis, collected in 1853 (Girard 1858: 21-22, 271-272), could have been taken from this

Cottonwood Creek, but most likely were collected from another (Beckwith 1854: 17) mentioned by Snyder

(1922) which traversed the Santa Fe Trail 27 km from Lost Spring. Contra Girard (1857a, 1858: 271-272),

Girard (1857b: 199) reported that the provenances of C. lugubris and C. ludibundus were unknown.

In Utah Lake forms of the generosus I platyrhynchus taxonomic complex, scales are smaller cranially than caudally, the head bears conspicuous mucous tubes, head length / total length (HL/TL) = 17.4-21.4%, the number of rays in the anal fin (A) = 7 (+ 2 rudimentary rays [at least in generosus]), the number of scales along the lateral line (Su) = 79-87, the number of longitudinal rows of scales above the lateral line

(S.) = 14-17, and the number of scale rows below the lateral line (SO = 11-14 (Girard 1857a, b: 174, 1858:

221-222, Cope 1876, Cope and Yarrow 1876: 673-675, 678, Jordan and Gilbert 1882: 123, Snyder 1922).

There are 4-5 rows of papillae in the distended lower lip and 2 in the upper lip (Jordan and Gilbert 1882).

Labial folds are pronounced and tuberculate; a notch exists where the posterior fold, which is deeply incised caudally, joins the anterior fold; lips have a horny tomium (cutting edge) due to a cartilaginous sheath that at least covers the labial commissure (Cope 1876, Cope and Yarrow 1876, Snyder 1916).

Although some of their traits are alike, body depth (BD) / TL = 13.5% in platyrhynchus but 17.4% in jarrovii; the number of dorsal-fin rays (D) = 11 in the former but 9 or 10 in the latter; the muzzle was depressed and very protuberant in the former but was tapered dorsally and only slightly protrusive in the latter; eye diameter (ED) / interorbital width = 60% in the former but 50% in the latter; predorsal length

= 47.0% in the former and 50.4% in the latter (Cope 1876, Cope and Yarrow 1876: 673-675, Jordan and

Gilbert 1882: 123). The light brown jarrovii had dusky spots and blotches, a faint abdominal stripe, and red fins; examples of platyrhynchus taken about Provo had a dusky dorsum and pinkish-yellow venter (Cope

1876, Cope and Yarrow 1876). In platyrhynchus, the orbit's superior border was indented, the caudal fin

(C) was openly emarginate, pectoral fins (P1) extended caudad halfway to the pelvic fins (P2), the latter did not reach the vent (see Fig. 1), and the sheathed labial commissure was transverse and abruptly angular laterally. In jarrovii, the sharp-edged sheath was convex rostrally. Labial folds were discoid-infundibular GREAT BASIN NATURALIST 8 in pbtyrhynchus, and narrow rostrally in jarrovii. Although some of the substantive differences between the

107-mm M. jarrovii and the 168-mm platyrhynchus may be related to age and the shriveled state of the platyrhynchus type mentioned by Jordan (1886), it is unlikely that they all are. Furthermore, the shriveled exemplar of platyrhynchus may not have been shrunken when Cope (1976) described this taxon, which was based also on several other syntypes. In A. generosus, predorsal length -,-..; 50%, and P2 originated ventrad to the caudal Vs of the dorsal fin; the distance from the snout's tip to P2 = 55.0% in platyrhynchus and

55.7% in M. jarrovii (Girard 1857a, b: 174, 1858: 221-222, Cope 1876, Cope and Yarrow 1876: 673-675,

678). generosus had a thick skull lacking a frontoparietal fontanelle; platyrhynchus had a thin skull bearing a rimiform (slit-like) fontanelle (Cope and Yarrow 1876: 678, Snyder 1916, 1922). Thus, generosus likely

platyrhynchus, but may = jarrovii (e.g., both generosus and jarrovii were squat, and in both, D = 10).

Mayden et al. (1992) regarded "Catostomus platyrhynchus" as polytypic. Utah examples must be reexamined.

It is crucial to be able to identify the larval Mountain Sucker so that it can be differentiated from the endangered (Lowe et al. 1990) June Sucker during recovery-program surveys. Analyses of supposed larval

June Sucker habitats that were undertaken in June of 1982-1984 were in vain; larval suckers that were collected from lower Provo River in those years (not 1982, 1983, and 1986 as Radant et al. [1987: 8, 10] mistakenly indicated) and sent to the Colorado State University Larval Fish Laboratory for identification were all determined to be Mountain Suckers. Moreover, those larvae that were garnered from Provo River in 1985 and placed in an isolated body of water for rearing were later identified as Mountain Suckers

(Radant et al. 1987: 10). Shirley (1983) described the ontogeny of the putative June Sucker via illustrations and textual data. However, almost all of the collected metalarvae (final larval stage) and juveniles, as well as some of the younger larvae upon which his analysis was based, were actually Mountain Suckers (Snyder and Muth 1988: 3). Snyder and Muth's (1988: 26-27, figs. 8-15, 37-43) identification guide demonstrates that the amount of melanistic pigment on the upper back and mid-ventral line of the larval June Sucker and

Utah Sucker (Catostomus ardens) is generally less than that in the larval Mountain Sucker. In the first 2 larval stages, the number of myomeres between the tip of the snout and the vent was 36 ± 1 (n = 22) in the Mountain Sucker but 38 ± 1 (n = 13) in the June Sucker; predorsal length in the 3rd and 4th (last) SUCKERS OF UTAH LAKE 9

larval stages were 48 ± 1% (n = 10) and 49 ± 1% (n = 12) of body length (BL), respectively, in the June

Sucker but 50 ± 1% (n = 11) and 51 ± 1% (n = 9) of BL, respectively, in the Mountain Sucker;

dorsal-fin lengths in those larval stages were 13 ± 1% (n = 9) and 17 + 1% (n = 9) of BL, respectively,

in examples of the Mountain Sucker, 15 ± 1% (n = 5) and 19 ± 1% (n = 12) of BL, respectively, in the

Utah Sucker, and 17 ± 1% (n = 5) and 22 ± 2% (n = 12) of BL, respectively, in the June Sucker (Snyder

and Muth 1988: tables 6, 11, 16). The sums of myomeres existing between the tip of the snout and the

origin of the dorsal finfold in the 1st and 2nd larval stages were 12 ± 1 (n = 10) and 12 ± 0 (n = 5),

respectively, in the Utah Sucker, but 15 ± 1 in both stages (n = 13) of the June Sucker (Snyder and Muth

1988: tables 6 and 11). In juveniles of the Mountain Sucker and Utah Sucker, the mouth and mandibles

migrate caudally as the young fish matures such that the mouth becomes inferior; contrariwise, the mouth

and mandibles of the June Sucker move little (Snyder and Muth 1988: figs. 16-17, 30-31, 44-45).

Unknown catostomid. This fish from Utah Lake resembled C. ardens but had a wider lower lip with 8-10

rows of smaller, coarse, irregular papillae (Jordan and Gilbert 1881). The dorsal lobe of the large C was

% the length of the head. This form's very long P1 were almost as long as its head, and P2 extended caudad

to the vent (Jordan and Gilbert 1881). The breast was almost scaleless. Unlike other Utah Lake catostomids,

the free posterior margins of the gill membranes formed a broad fold across the narrow isthmus, as in

Coitus. Jordan and Gilbert (1881) opined that if the structure of the isthmus were to persist during continued

growth and development, this form probably ought to be regarded as a member of a distinct genus. Fil 5. 014,,J 3 item, Utah Sucker Catostomus ardens (burning low-mouth: Latin ardens, burning or flaming; in reference to a

bright rosy lateral band appearing on males at least in the breeding season). Cope and Yarrow (1876: 679)

synonymized a specimen called Catostomus guzmaniense (sp.) that Henry Crecy Yarrow and H. W.

Henshaw had collected at Utah Lake in July 1872, with Catostomus (Acomus) guzmaniensis (Girard 1857b:

173) whose syntypes had been taken in Janos River, a tributary of Guzman Lake in Chihuahua Province,

Mexico (Cope and Yarrow 1876), far removed from Bonneville Basin. Later, guzmaniensis became

subsumed within Pantosteus (= Notolepidomyzon = Catostomus) plebeius (Jordan 1891: 20, Jordan et al.

1930: 104, Robins et al. 1991). Jordan and Gilbert (1881), who originally described Catostomus ardens, GREAT BASIN NATURALIST 10 suspected that guzmaniense was an example. Since 1881, there has been no mention of it. A comparison of the Utah Sucker with other Utah Lake catostomids is provided for larvae and juveniles above in the section on the Exceptional Sucker / Mountain Sucker, and for adults in the next section on the Webug Sucker.

Webug Sucker Chasmistes fecundus (fecund yawner: Greek chasmao, to yawn or gape; Latin fecundus, fecund). Four specimens or specimen lots of putative Catostomus fecundus that had been acquired in Utah

Lake by H. C. Yarrow and H. W. Henshaw in 1872 were described and compared with Catostomus

(Acomus) generosus by Cope and Yarrow (1876: 678-679). Upon examination of some exemplars of

"fecundus", Jordan (1878a, b: 149-151) concluded that they belonged to an undescribed genus which he differentiated from Catostomus and named Chasmistes. Then in the addendum to the latter treatise, Jordan

(1878b: 219-220) indicated that after reexamining Cope and Yarrow's (1876: 678-679, plate 32) textual description and drawing of fecundus, his notes on those authors' "typical" specimens of fecundus, and the exemplars on which his description of the genus Chasmistes was based, Jordan concluded that the examples of Chasmistes belonged to a species distinct from fecundus which he named liorus. Hence, Jordan's (1878a, b: 149-151) description of fecundus actually refers to liorus. Later, Jordan (1882: 129) provided a substantive characterization offecundus. Although Jordan (1878b: 219-220) had earlier supplied information on the Webug Sucker after it had been differentiated from the June Sucker, most of that report was a reiteration of Cope and Yarrow's (1876: 678-679) description. After analyzing a specimen at the U.S.

National Museum which Jordan (1878b) considered to be typical of fecundus, he affirmed that fecundus belonged to the genus Catostomus rather than Chasmistes. Ironically, the mouth of that particular exemplar was in poor condition so he was unable to evaluate its lips. Jordan (1878b: 149-150) had previously noted that the mouth and lips are of "singular" importance in differentiating Chasmistes from Catostomus. Jordan

(1878b: 219-220) assigned 2 specimens or 2 lots of specimens from the U.S. National Museum that had been collected at Utah Lake by Yarrow and Henshaw, to fecundus. Subsequently, the Webug Sucker was known as Catostomus fecundus (Jordan and Gilbert 1881, 1882, Jordan 1891, Jordan and Evermann 1896a:

180-181) until it was again placed in the genus Chasmistes (Jordan and Evermann 1896b: 240, 1898: 2794,

Jordan et al. 1930: 108). Tanner (1936) believed that there was but 1 species of sucker in Utah Lake which SUCKERS OF UTAH LAKE 11 he referenced as Catostomus fecundus. However, his view later changed. Lowder (1951: 1), one of Tanner's students, inspected 6783 suckers for his thesis project. Finally, after surveying = 6700 of these fish, Lowder

(1951) concluded that they actually belonged to 3 species, and took measurements of individuals that were subsequently caught. Another student under Tanner's advisement (Stubbs 1966: 6, 10) inspected > 1000 catostomids, identifying a few Webug and Utah Suckers as well as numerous June Suckers. In taxonomically categorizing mature adult ( 3 yr of age) specimens, Stubbs (1966: 1-4, 11) referred to their descriptions by Cope and Yarrow (1876: 678-679), Jordan and Gilbert (1881), Jordan and Evermann (1896a: 179-183), and perhaps Jordan (1891); he did not allude to the generic or specific treatments of these forms by Jordan

(1878b: 149-151, 219-220) and Jordan and Gilbert (1882: 128-129, 131-132). Stubbs' (1966: iii, 11, tables

1-3) thesis advisor verified his identifications, and ultimately 25 specimens representing the 3 year-round catostomids of Utah Lake were selected for detailed osteological examinations. Stubbs (1966: 52) referred to the Webug Sucker as Catostomus fecundus as his advisor had done (Tanner 1936), but concluded that it is much more closely related to the June Sucker than to the Utah Sucker, and that the Webug and June

Suckers have a common immediate ancestor, thus corroborating the position of Jordan and Evermann

(1896b, 1898) and Jordan et al. (1930) that fecundus belongs in the genus Chasmistes. Based on Miller and

Smith's (1981: 11) contention that fecundus is not a distinct taxon, Robins et al. (1991) did not include it in their checklist of North American piscine species. Miller and Smith (1981), who did not make reference to Jordan and Evermann (1896b, 1898), Jordan et al. (1930), Lowder (1951), or Stubbs (1966), alluded to the Webug Sucker as Catostomus fecundus as Jordan and Evermann (1896a) had done.

Note that the description of Chasmistes (Jordan 1878b: 149-150) leads to the inference that it was based on both the Webug and June Suckers even though this description was restated by Jordan and Gilbert (1882:

131), and to a large extent by Jordan and Evermann (1896a: 182), during the period that the genus was considered to be monotypically represented by the June Sucker. Some generic traits that are detailed in that description such as "anal fin high (deep), reaching caudal", "pectorals rather long, not quite reaching ventrals (pelvic fins)", and "eyes ... high up, rather posterior" conform to characterizations of the Webug GREAT BASIN NATURALIST 12

Sucker rather than the June Sucker (see below). The ascription of an evenly lobed tail to Chasmistes by the generic description is not warranted by the recorded features of either sucker.

It was Stubbs' (1966: 8, 51) view that the shape of the head and snout, and the position of the mouth are the external features that best differentiate the 3 year-round catostomids of Utah Lake. With reference to the anterior dorsum's contour, Stubbs (1966: 29, fig. 42) noted that the dorsal surface of the Webug

Sucker is "moderately decurved" rostrad from its back which, according to Jordan (1881), is "a little elevated". Jordan and Gilbert (1881, 1882: 129), Jordan (1891), and Jordan and Evermann (1896a: 180-181) reported that the dorsal surface of the Webug Sucker is regularly decurved from the nape to the base of the premaxillary spines which project rostrally on roughly a horizontal plane to form a markedly protuberant snout (see Fig. 4). Rostrad to its dorsal fin, the dorsal profile of the June Sucker is almost horizontal, according to Stubbs (1966: 29; contra Fig. 6). Fig. 6 shows that the front and back of the June Sucker's head are roughly on the same horizontal plane, unlike the head of the Webug Sucker (Fig. 4) and especially the Utah Sucker (Fig. 3, contra Fig. 2). From a more detailed perspective (Jordan 1878b: 149-150, Jordan and Gilbert 1881, 1882: 131, Jordan and Evermann 1896a: 182), the June Sucker's head is dorsally concave or depressed, low at the nape, and highest at the tip of the prominent upturned snout and its caudal extremity. The interorbital span is markedly convex in the Webug Sucker, but very broad and nearly flat in the June Sucker (Jordan and Gilbert 1881, 1882: 132, Jordan and Evermann 1896a: 183). In the Utah

Sucker, the premwdllae are scarcely elevated above the level of the mandibles (Fig. 3, contra Fig. 2; Jordan

1881). In the Webug Sucker, the caudal peduncle is long and thin, and the lower lobe of the slender, moderately forked tail is longer and wider than the upper (contra Fig. 4); the June Sucker's lower lobe is also the longer one, but its caudal peduncle is rather stout (contra Fig. 6) (Jordan 1878b: 149-150, Jordan and Gilbert 1881, 1882: 129, 131-132; Jordan and Evermann 1896a: 180-181, 183, 1902: 54-55, 1934:

54-55). In the Utah Sucker, the lobes of the short and broad tail (Fig. 3, contra Fig. 2) are roughly even

(Jordan and Gilbert 1881, 1882: 128-129, Jordan 1891, Jordan and Evermann 1896a: 179-180, 1902: 52-53,

1934: 52-53). From the characteristics of Utah Lake catostomids, Stubbs (1966: 44-45, plate 5) deduced that the Utah Sucker is the most elongate and fusiform with the narrowest back and shoulders, and that the June SUCKERS OF UTAH LAKE 13

Sucker has the broadest back and shoulders. Jordan and Gilbert's (1881) account confirms that the June

Sucker is bulky at the shoulders. Although the publications of Jordan and Gilbert (1881, 1882) and Jordan and Evermann (1896a, 1902) corroborate that the Utah Sucker has a rather elongate, subfusiform body with a dorsally convex and subconic head, they also indicate that the slightly elevated back of this species is wide.

According to the description of Chasmistes (Jordan 1878b: 149-150, Jordan and Gilbert 1882: 131), the June Sucker's mucous-channeled head is widest dorsally, and has sides that may be directed somewhat ventromediad. Jordan (1881) and Jordan and Evermann (1896a: 179-180, 1902: 52-53, 1934: 52-53) stated that the Utah Sucker's head is broad, at least dorsally. Stubbs (1966: 44-45, plate 5) noted that the Utah

Sucker has the smallest (cuneate or subconic) head (Fig. 3, contra Fig. 2). Recorded HLs of Utah Lake suckers are on a crude average, relatively smallest for the Webug Sucker at 20-25% (Cope and Yarrow

1876: 678-679, Jordan and Gilbert 1882: 129, Jordan and Evermann 1896a: 180-181, Stubbs 1966: derived from table 7) of BL. HL/BL = 22.9-29.4% (mode of =27%) in the June Sucker (Jordan and Gilbert 1882:

132, Jordan and Evermann 1896a: 183, 1902: 54-55, 1934: 54-55, Stubbs 1966; plate 5, Miller and Smith

1981: mean derived from table 1), and 20.0-27.3% (Jordan and Gilbert 1881, 1882: 128-129, Jordan 1891,

Evermann 1893: 42, Gilbert and Evermann 1895, Jordan and Evermann 1896a: 179-180, 1902: 52-53,

Stubbs 1966) in the Utah Sucker. The front of the Utah Sucker's small (ED/HL = 14-19%) eye (Fig. 3, contra Fig. 2) lies = midway in the head (Jordan and Gilbert 1881, 1882, Evermann 1893, Gilbert and

Evermann 1895, Jordan and Evermann 1896a: 179-180, 1902: 52-53). In the Webug Sucker, the eye is the same size but is positioned slightly caudad to the mid-head (Jordan and Gilbert 1881, 1882: 129, Jordan and

Evermann 1896a: 180-181). Jordan and Gilbert (1881) averred that rostrocaudally, the small (ED/HL =

11-17%) eye of the June Sucker exists exactly at the midpoint of the head's side (Jordan and Gilbert 1881,

Jordan and Gilbert 1882: 132, Jordan and Evermann 1896a: 183, Miller and Smith 1981: table 1). SL/HL

= 42.9% in the June Sucker and 40.0-44.4% in the Utah Sucker; BD/BL = = 20% in the June Sucker,

20.0-22.7% in the Utah Sucker, and 22.2% in the Webug Sucker (Jordan and Gilbert 1881, 1882: 128-129,

132, Evermann 1893, Gilbert and Evermann 1895, Jordan and Evermann 1902: 52-55, 1934: 52-55). In the

Utah Sucker, the thick, very wide, and pendent upper lip comprises 4-5 (Jordan 1891), 4-8 (Jordan and GREAT BASIN NATURALIST 14

Evermann 1896a: 179-180, 1902: 52-53), or 8 (Jordan and Gilbert 1881, 1882: 128-129) rows of coarse, irregular papillae that may be largest in the 2nd and 3rd rows from the lingual side; the lower lip, composed of 2 narrowly spaced lobes, is very broad, and deeply incised medially across its entire width. The Webug

Sucker's pendent, rather smooth, and somewhat protrusive upper lip contains 4 rows of large, coarse papillae, and a wide medial gash separates the 2 lobes of the lower lip which bear 6 rows of papillae; lips of the June Sucker are smooth and nonpapillose or nearly so (Jordan 1878b, 1891, Jordan and Gilbert 1881,

1882: 129, 131, Jordan and Evermann 1896a: 180-182, Holden et al. 1974, Shirley 1983). The rather protrusive upper lip of the June Sucker is very thin; each of the widely separated lobes of the medially incised lower lip lies laterad to a mandible, is weakly folded with slightly uneven plicae, and narrows rostrally to become a medial rim (Jordan 1878b, Jordan and Gilbert 1881, 1882: 131, Jordan and Evermann

1896a: 182, Shirley 1983). Holden et al. (1974) claimed that the June Sucker's upper lip is concealed by an overhanging snout. This sucker's robust mandibles, which 35-45% of HL and become proportionately

0 0 larger with age, form angles of 45 and 315 with the craniocaudal axis (Jordan 1878b, Jordan and

Gilbert 1881, 1882, Jordan and Evermann 1896a). In the Webug Sucker, large mandibles form angles of

60° and 300° with that axis (Jordan and Gilbert 1881, 1882: 129, Jordan and Evermann 1896a: 180-181), or are almost as oblique as those of the June Sucker (Jordan 1891). Smaller mandibles bordering the Utah

Sucker's inferior mouth are horizontal (perpendicular to the body axis) or only slightly oblique, and measure

< 1/3 of HL (Jordan and Gilbert 1881, 1882: 128-129, Jordan 1891, Jordan and Evermann 1896a: 179-180,

1902). The very large mouth of the June Sucker and the smaller mouth of the Webug Sucker are terminal or subterminal (Jordan 1878b, 219, 1891, Jordan and Gilbert 1882: 131, Jordan and Evermann 1896a: 182,

Sigler and Sigler 1987: 239-241, Page and Burr 1991: 167-168).

Stubbs (1966: 44-45) related that the Utah and Webug Suckers have relatively high fins and that the

June Sucker has the smallest fins (Figs. 3-4, 6). In partial corroboration, Jordan and Gilbert (1881) affirmed that the anal fin is deep in the Webug Sucker (Fig. 4), and very deep and long in the Utah Sucker, reaching the base of C caudally (Fig. 3, contra Fig. 2). Jordan and Gilbert (1882: 128-129) and Jordan and Evermann

(1896a: 179-180, 1902: 52-53, 1934: 52-53) characterized the anal fin of the Utah Sucker as long rather than SUCKERS OF UTAH LAKE 15 deep. Jordan and Gilbert (1881, 1882: 129, 132) and Jordan and Evermann (1896a: 180-181, 1902: 54-55,

1934: 54-55) confirm that the Webug Sucker's anal fin is deep, and the June Sucker's ventral fins are small

(Figs. 4 and 6). Jordan (1891) mistakenly indicated that the June Sucker's fins are large. Jordan (1891) stated that the Webug Sucker's ventral fins are long; indeed, the relatively long P1 certainly extend >1/2 the distance between their origin and that of P2 (Jordan and Gilbert 1881, 1882: 129, Jordan and Evermann

1896a). The Utah Sucker's P1 are short and broad, and its squat P2 do not reach the vent caudally (Fig. 2;

Jordan and Gilbert 1881, 1882: 128-129, Jordan 1891, Jordan and Evermann 1896a: 179-180, 1902: 52-53,

1934: 52-53). In the Webug Sucker, the dorsal fin's anterior ray is about twice the height of the posterior ray, and longer (Jordan and Gilbert 1881, 1882: 129; Jordan and Evermann 1896a: 180-181) or almost as long (Jordan 1891) as that fin's basal length (Fig. 4). In the June Sucker, the anterior ray is about twice the height of the posterior ray and 83% (Jordan 1891) or 100% (Jordan and Gilbert 1881, 1882: 132, Jordan and Evermann 1896a: 183, 1902: 54-55) of the basal length (Fig. 6). The height of the anterior ray of the

Utah Sucker's dorsal fin is only 1.5 times that of the posterior ray and 75-100% of that fin's basal length

(Fig. 3, contra Fig. 2; Jordan and Gilbert 1882: 128-129, Jordan 1891, Jordan and Evermann 1896a:

179-180, 1902: 52-53). Jordan and Gilbert (1881) noted that the free margin of the June Sucker's dorsal fin is almost straight, but Jordan (1891) related that it is slightly concave (Fig. 6).

According to Jordan and Gilbert (1881, 1882: 129), the Webug Sucker is dusky dorsally due to dense dark stippling, and pallid or silvery ventrally. Jordan (1891) noted that it is rather pale. In the June Sucker, the olive dorsum is so profusely and darkly stippled or mottled that it appears dusky; the venter is pallid or white, and the fins are pale except at their fuliginous tips (Jordan and Gilbert 1881, 1882: 132, Jordan 1891,

Jordan and Evermann 1896a: 183). The Utah Sucker has a dusky dorsum that is blotched with black, sides that are vaguely spotted, a white venter, and fins or ventral fins that are mottled with fuliginous (Jordan

1881, 1891, Jordan and Gilbert 1882: 128-129, Jordan and Evermann 1896a: 179-180). Rockwood (1873) commented that the general coloration of this species varies from crimson to dark green. The Utah Sucker is darker than the Webug Sucker (Jordan 1891) and the June Sucker (Rockwood 1873), but at least anteriorly, the male (Jordan and Gilbert 1881, 1882: 128-129, Jordan and Evermann 1896a: 179-180) or breeding male (Sigler and Sigler 1987) possesses a bright rosy lateral band. GREAT BASIN NATURALIST 16

The adult Utah Sucker of Utah Lake had a TL of 46 cm (Jordan and Gilbert 1881, 1882: 128-129,

Jordan and Evermann 1896a: 179-189), a modal mass of =0.7 kg, and a maximal mass of = 2.3 kg

(Rockwood 1873). In the 1800s, the June Sucker's TL typically = 46 cm (Jordan and Gilbert 1881, 1882:

132, Jordan and Evermann 1896a: 183). Jordan (1891) stated that its maximal mass = 1.4 kg. Because there has been little recruitment of young into the June Sucker population in recent years, this taxon's average size has been continually increasing (Gutermuth and Lentsch 1993: 2-3, Gutermuth et al. 1993: 2, 14-15, table 3). The mean mass of 126 suckers (of which 81% were June Suckers) that were netted in Utah Lake in 1978-1979 was 1.6 kg (Radant and Sakaguchi 1981b: 141). Mean mass = 2.4 kg among 35 spawning

June Suckers in 1991 (Gutermuth and Lentsch 1993: table 1, omitting the captive specimen), and 2.3 kg among 57 spawning June Suckers in 1992 (Gutermuth et al. 1993). Mean TL among 45 male and 51 female

June Suckers within Utah Lake in 1978-1979 = 50 cm and 55 cm, respectively (overall X = 52 cm) (Radant and Sakaguchi 1981b). In both 1991 (n = 36) and 1992 (n = 56), mean TL of spawners = 53 cm for males and 57 cm for females (Gutermuth and Lentsch 1993: 8, Gutermuth et al. 1993: 8). Jordan (1878b), Jordan and Gilbert (1881, 1882), Jordan (1891), and Jordan and Evermann (1896a) declared that with a TL of

30-33 cm and a mass normally < 0.5 kg, the Webug Sucker is the smallest year-round catostomid of Utah

Lake. Stubbs' (1966: tables 1-3) data corroborate that the BL of the Webug Sucker (X = 25 cm, n = 5) is appreciably < that of the Utah Sucker (X = 38 cm, n = 9) and June Sucker (X = 40 cm, n = 11), although

Lowder (1951: tables 1-5) indicated that the BL of the Webug Sucker (X = 28 cm, n = 18) is > that of the Utah Sucker (X = 24 cm, n = 19) but < that of the June Sucker (X = 32 cm, n = 8).

The validity of Lowder's (1951) data on Utah Lake catostomids hinges on his ability to initially differentiate them correctly based principally on the use of mouth and head morphologies (see Stubbs 1966:

6). In identifying the Webug Sucker, Lowder (1951: 17-18) apparently relied heavily on the only published characterization of this species reproduced in his thesis (Cope and Yarrow 1876: 678-679), which ironically did not refer to mouthparts. Lowder (1951: 44) relied on Jordan (1878b: 149-150) for the description of

Chasmistes (he mistakenly put "pp. 219" at the end of his citation of Jordan's [1878b] article). Stubbs

(1966: 7-8) noted that the configuration, papillosity, and plication of lips, which Lowder (1951) had largely SUCKERS OF UTAH LAKE 17

(1966: 7-8) noted that the configuration, papillosity, and plication of lips, which Lowder (1951) had largely employed to differentiate catostomids, are inconstant. Lowder (1951) did not allude to the characterizations of Utah Lake suckers made by Jordan and Gilbert (1882: 128-129, 131-132) and Jordan (1891). Lowder

(1951: 11) described only 1 ideal representative specimen from each of the 3 year-round catostomid taxa.

He did not statistically compare the 25 measurements and enumerations that he made on 45 collected specimens, and did not delineate any morphometric, enumerative, or gross anatomical boundaries that he might have used in assigning a sucker to 1 of the 3 species. Lowder (1951: 1, 9, 10, tables 1-5), who claimed to have inspected 6782 netted suckers in 1950-1951 and to have performed complete measurements on .-=', 100 of them (dimensions of 45 specimens are recorded), "recognized" near the end of his field survey of year-round Utah Lake catostomids that there were 3 species. Lowder (1951: 1, 7, 9) repeatedly alluded to the presence of 3 suckers, and devoted the body of his treatise to the presentation of morphologic data for the 3 forms. Lowder (1951: 15-16) affirmed that the Webug Sucker's short mandible, inferior mouth, and papillose lips clearly place it in Catostomus. But Lowder (1951: 42) later attested that the catostomids exhibited a continuum of lip and head traits that included all transitional stages of the features that had been described for these forms, concluding "that there is either two genera and three species or one genus and one species of suckers in Utah Lake." Then, Lowder (1951: 42) avowed that there must be 2 sucker species present because the June Sucker spawns in April and the Utah and Webug Suckers spawn in June.

The June Sucker derives its name from the month during which its spawning activity has most often peaked

(see Cope and Yarrow 1876: 678, Jordan 1878b: 150-151, Jordan 1891, Stubbs 1966: 49, Radant and

Sakaguchi 1981b: 144, 146-148, 150, Radant and Shirley 1987: 12-15, Radant et al. 1987: 1-2, 21, fig. 7,

Modde and Muirhead 1990: 4-5, 1994, Gutermuth and Lentsch 1993: table 1, Gutermuth et al. 1993: Figs.

6-7, Holden et al. 1994: 19, 27, U.S. Fish and Wildlife Service [USFWS] 1995: 8). The Webug Sucker also likely spawns in June (Cope and Yarrow 1876: 678-679, Jordan 1878b: 219-220). The Utah Sucker breeds in March (Jordan 1891), late March and early April (Stubbs 1966: 49, Radant and Salcaguchi 1981b: 144),

April (Radant et al. 1987: 2), or April-May (Holden et al. 1994: 19). Reiterating the existence of a GREAT BASIN NATURALIST 18

There is a question whether Lowder (1951) accurately identified Utah Lake suckers. His 3 representative specimens of the Utah Sucker, Webug Sucker, and June Sucker conveniently had mandibles with ideal conformations (Jordan 1878b: 149-150, Jordan and Gilbert 1881, 1882: 128-129, 131, Jordan and

Evermann 1896a: 179-183), forming angles of 90° and 270°, 60° and 300°, and 45° and 315°, respectively, with the body's craniocaudal axis. Lowder (1951: 15-16) attested that the Webug Sucker's general appearance, short mandible, and inferior mouth, as well as its thick lips covered with spongy papillae, clearly place it in Catostomus. Although the mouth of the Webug Sucker is not big, its mandibles, similar to those of the June Sucker, are large and long ( =36% of HL) (Jordan and Gilbert 1881, 1882: 129, Jordan

1891, Jordan et al. 1896a: 180-181). Since Jordan and Evermann (1896b: 240, 1898: 2794) and Jordan et al. (1930: 108) decided to place fecundus back in the genus Chasmistes, it may be assumed that the position of the Webug Sucker's mouth approximates that described for the genus (i.e., terminal) (Fig. 4, contra

Fig. 5; Jordan and Gilbert 1882: 131, Jordan et al. 1896a: 182). More specifically, Jordan (1878b: 219) asserted that the conformations of the mouth and snout in the Webug and June Suckers are "very similar".

Robert Rush Miller and Carl L. Hubbs had a notion that the Webug Sucker was a hybrid of the Utah and June Suckers (Sigler and Miller 1963: 164-165, Holden et al. 1974). Perhaps Miller and Smith (1981) attempted to confirm that suspicion. Their hypotheses have engendered uncertainty about the ancestry of the contemporaneous June Sucker and the legitimacy of the Webug Sucker as a distinct species, and have been accepted (usually uncritically) by most authors who have alluded to their monograph (Radant and Sakaguchi

1981a: 11, b: 135, 136, 139, Snyder and Muth 1988: 3, Modde and Muirhead 1990: 1, Gutermuth and

Lentsch 1993: 2-3, Holden et al. 1994: 19, 23, Utah Lake Fish Management Advisory Team 1994: 16, 31, but see USF'VVS 1995: 1, 3). Miller and Smith (1981: 9, 11) postulated that Catostomus fecundus was a hybrid of Catostomus ardens and Chasmistes liorus prior to a severe drought that continued from 1932-1935 and left Utah Lake almost dry during the winter of 1934-1935 (see Tanner 1936). They proposed that a self-perpetuating hybrid distinct from the apparently non-reproducing hybrid, Catostomus fecundus, arose from the same parental Utah and June Suckers during the period of extreme low water in Utah Lake, but that this form belongs to a different genus than its pre-drought sister hybrid, C. fecundus. The putative SUCKERS OF UTAH LAKE 19 post-drought hybrid was named Chasmistes liorus mictus (Miller and Smith 1981: 15, 17). One of its parents, Chasmistes liorus Ilona, is supposedly extinct; the other parent, Catostomus ardens, is extant. It is remarkable that partially on the basis of anatomical measurements of only 3 pre-drought and 9 post-drought specimens of the June Sucker, and the inspection of 6 exemplars of the Webug Sucker, Miller and Smith (1981: 11, table 1) contended that the original form of the June Sucker no longer survives, that

"it is unlikely that Catostomus fecundus ever existed as a distinct species in (Utah) (L)ake", and that the existing June Sucker is a self-propagating intergeneric (not interspecific) hybrid. These authors did not refer to the investigations of Lowder (1951) and Stubbs (1966) involving at least the cursory inspection of thousands of Utah Lake suckers. Photographs presented in their report render some of their hypotheses suspect. The hippocrepiform mouth of a specimen of Miller and Smith's (1981) Chasmistes liorus mictus

(Fig. 9C) resembles the hippocrepiform mouth of the single displayed specimen of C. 1. liorus (Fig. 7A), rather than the lunate mouth of another supposed example of C. 1. mictus (Fig. 7B). Moreover, the mouth of the latter mictus appears smooth whereas the mouth of two other examples of putative mictus (Figs. 9B and 9C) are papillose. In contrasting gill-raker counts, Miller and Smith (1981: table 3) examined larger samples of 14 supposed liorus and 32 mictus, as well as 18 C. ardens, and found little morphologic overlap taxonomically. Five photographs depicted the gill rakers of liorus to be rather amorphous, those of mictus to be compactly columnar, and those of fecundus to be sparsely columnar (Miller and Smith 1981: fig. 8).

Comparisons of 22 anatomical lengths in 3 specimens of pre-drought and 9 examples of post-drought June

Suckers revealed 3 dimensions that did not interspecifically overlap (Miller and Smith 1981: table 1). These measurements of predorsal length, HL, and ED were assessed in somewhat larger samples of 8 pre-drought and 19 post-drought June Suckers, and showed little inter-sample overlap (Miller and Smith 1981: table 2).

With respect to the distance between the occiput and the origin of the dorsal fin, the greatest length recorded in 9 post-drought suckers was only 0.1% > the shortest length registered in 3 pre-drought suckers (31.5% of BL - represented by 2 pre-drought individuals) (Miller and Smith 1981: table 1). However, this length and predorsal length measure, to an appreciable extent, the same dimension. Miller and Smith (1981) performed a series of measurements and enumerations only on Utah Lake's pre- and post-drought June GREAT BASIN NATURALIST 20

Suckers. Except with respect to 1 trait, they did not compare putative Chasmistes 1. liana and C. 1. mictus with Catostomus ardens to determine whether the dimensions or counts in mictus were intermediate. Also, they did not attempt to match specimens and recorded traits of putative C. 1. mictus with exemplars and recorded characteristics of the Webug Sucker to assess whether these forms might be synonymous. After measuring anatomic lengths, assessing the number and structure of gill rakers, counting scales, and analyzing head and mouth anatomies, Miller and Smith (1981), without performing statistical tests on their small samples, concluded that predorsal and caudal-peduncle lengths, mouth shape, lip papillosity, scale counts, and gill-raker shape and density, as well as head, mandibular, and ocular sizes in the putative ancestral and hybrid forms of the June Sucker are different. In totality, data on these forms from all sources (see herein) do not show clear morphological differences; gill-raker counts are the most discriminating.

Lowder (1951: 41) attested that scale enumerations among the 3 year-round catostomids of Utah Lake completely overlap. The following data show, contra Miller and Smith (1981: 15), that scale counts are too variable to be of taxonomic value in distinguishing Utah Lake suckers. Reported values of Sll for pre-drought

June Suckers were 61 (Jordan and Gilbert 1881), 63 (Jordan and Gilbert 1882: 132, Jordan and Evermann

1896a: 183, 1902: 54-55, 1934: 54-55), 66 (Jordan 1891), but also 55-64 (Miller and Smith 1981: 12). In post-drought June Suckers, these quantities were 62-68 (2 = 64.4, n = 7) (Stubbs 1966: table 6), 60-70

(Miller and Smith 1981: 15), and 62-69 (2 = 65.2, n = 8) (Lowder 1951: table 1). Su in the Webug Sucker

= 60 (Cope and Yarrow 1876: 678-679, Jordan and Gilbert 1881, 1882: 129), 64 (Jordan 1891, Jordan and

Evermann 1896a: 180-181), 64-70 (2 = 67.4, n = 10) (Stubbs 1966), but also 65-72 (2 = 68.3, n = 18)

(Lowder 1951: tables 4-5). In the Utah Sucker, Su = 65 (Jordan and Gilbert 1881, 1882: 128-129), 61-69

(2 = 66.1, n = 10) (Stubbs 1966), 63-71 (Jordan 1891), 66-71 (67.8 + 2.1, n = 6) (Gilbert and Evermann

1895), 70-72 (Jordan and Evermann 1896a: 179-180, 1902: 52-53, 1934: 52-53), but also 61-79 (2 = 67.3, n = 18) (Lowder 1951: tables 2-3). S. in the pre-drought June Sucker = 7 (Jordan 1881), 9 (Jordan and

Gilbert 1882: 132, Jordan and Evermann 1896a: 183, 1902: 54-55), and 9-11 (Miller and Smith 1981: 12);

S. in the post-drought June Sucker equaled 10-13 (2 = 11.6, n = 8) (Lowder 1951: table 1) and 11-14

= 12.4, n = 12) (Stubbs 1966: table 5). In the Webug Sucker, S. = 8 (Jordan and Gilbert 1881, 1882: SUCKERS OF UTAH LAKE 21

129; Jordan and Evermann 1896a: 180-181), 10 (Cope and Yarrow 1876: 678-679), 10-12 (g = 11.1, n = 10) (Stubbs 1966), but also 11-14 (g = 12.3, n = 18) (Lowder 1951: tables 4-5). S. in the Utah Sucker

= 9 (Jordan and Gilbert 1881, 1882: 128-129), 10 (n = 2; Gilbert and Evermann 1895), 10-13 (g = 11.8, n = 10) (Stubbs 1966), 12 (Jordan and Evermann 1896a: 179-180, 1902: 52-53), and 10-14 (g = 11.9, n =

18) (Lowder 1951: tables 2-3). St, in the pre-drought June Sucker = 8 (Jordan and Gilbert 1882: 132, Jordan and Evermann 1896a: 183, 1902: 54-55), 9 (Jordan and Gilbert 1881), and 8-10 (Miller and Smith 1981:

12). In the post-drought June Sucker, Sb = 8-11 (g = 9.2, n = 12) (Stubbs 1966) and 9-12 (g = 10.2, n =

8) (Lowder 1951: table 1). Sb in the Webug Sucker = 8 (Jordan and Gilbert 1881, 1882: 129, Jordan and

Evermann 1896a: 180-181), 8-9 (g = 8.8, n = 5) (Stubbs 1966), 10 (Cope and Yarrow 1876: 678-679), but also 10-14 (g = 11.3, n = 18) (Lowder 1951: tables 4-5). Cope and Yarrow (1876) recorded that S.

± Sb = 19 in the Webug Sucker. In the Utah Sucker, ST, = 8 (n = 2; Gilbert and Evermann 1895), 8-10

(g = 9.1, n = 10) (Stubbs 1966), 9 (Jordan and Gilbert 1881, 1882: 128-129), 12 (Jordan and Evermann

1896a: 179-180, 1902: 52-53), but also 9-14 (g = 10.9, n = 18) (Lowder 1951: tables 2-3). Hence, authors in the 1800s generally recorded higher scale counts for June and Webug Suckers than those in the 1900s.

The lowest value of Su that Miller and Smith (1981: 12) reported for pre-drought June Suckers (=55) is by far the lowest. The magnitude and variability of Lowder's (1951: tables 1-5) scale counts are high.

Lowder (1951: 41) related that neither D nor A is unique for any year-round Utah Lake catostomid, and without evidence, maintained that the lengths of these fins are dependent on gender and reproductive condition. Jordan and Gilbert (1881, 1882: 128-129, 132), Gilbert and Evermann (1895), and Jordan and

Evermann (1896a: 179-183, 1902: 52-55, 1934: 52-55) concurred that A = 7 in these 3 catostomids. Cope and Yarrow (1876: 678-679) recorded that A = 8 (+ 1 rudimentary ray) in the Webug Sucker. Lowder

(1951: tables 1-5) recorded that A = 7 in 1 June Sucker and 8 in 7 others. In the pre-drought June Sucker,

D = 11 (Jordan and Gilbert 1881, 1882: 132, Jordan and Evermann 1896a: 183, 1902: 54-55, 1934: 54-55) and 13 (Jordan 1891). In the dorsal fin of the post-drought June Sucker, Stubbs (1966: table 5) found 11-13

(mode of 12) rays and Lowder (1951: table 1) counted 12-13 (mode of 12) rays. The number of dorsal-fin rays in the Webug Sucker has been registered as 11 (Jordan and Gilbert 1881, 1882: 129), 11-12 (Jordan GREAT BASIN NATURALIST 22

1891, Jordan and Evermann 1896a: 180-181), 12-13 (Cope and Yarrow 1876: 678-679, Lowder 1951: tables

4-5 [mode of 12]), and 13-14 (mode of 13) (Stubbs 1966). In the Utah Sucker, D = 12-13 (Jordan and

Gilbert 1881, 1882: 128-129; Jordan 1891, Gilbert and Evermann 1895, Jordan and Evermann 1896a:

179-180, 1902: 52-53, 1934: 52-53, Lowder 1951: tables 2-3 [mode of 12], Stubbs 1966). Hence, recorded fin-ray number, which has increased with time in all 3 species, is not a useful discriminator of these suckers.

Noteworthily, not all of the traits of Lowder's (1951) Webug Sucker were intermediate between those of the June Sucker and the Utah Sucker. For example, the basal length of the dorsal fin as a percentage of

BL was 16.3% (n = 18) in the Webug Sucker, 17.9% (n = 8) in the June Sucker, and 18.2% (n = 19) in the Utah Sucker; the length of the anal fin's base / BL was 7.6% (n = 18) in the Webug Sucker, 8.2% (n =

19) in the Utah Sucker, and 9.0% (n = 8) in the June Sucker (Lowder 1951: tables 1-5). Note, however, that Jordan and Gilbert (1881, 1882: 128-129, 132), Jordan and Evermann (1896a: 179-181, 183), and

Stubbs (1966: 44-45) indicated that these fins are shortest in the June Sucker. Stubbs (1966: 49-50) proclaimed that, of the > 1000 specimens belonging to 3 catostomid species that he examined, "not one was identified as an intermediate" although each taxon possessed some characters that were. For example, mouth and lip characters in the Webug Sucker, dorsal-rib morphology in the Utah Sucker, and the anteroposterior positioning of the articular process within the tripus (see below) of the June Sucker were intermediate

(Stubbs 1966). The treatment of catostomids given earlier in this section indicates that the Webug Sucker is not intermediate in body mass, eye position, or the relative lengths of the body, head, and P1. Other examples of non-intermediacy in this sucker are the shape and relative size of the dorsal spine complex, length and shape of the anterior ramus of the tripus, and length of the first vertebral centrum (= 0.52% in the Utah Sucker, 0.56% in the June Sucker, and 0.63% of BL in the Webug Sucker; Stubbs 1966: table 4).

Smith (1983) claimed that "hybrid" June Suckers that were taken by Carl L. Hubbs and Vasco Tanner in the 1940s were smaller with a more inferior mouth and more papillose lips than pre-drought forms. Since the nonhybrid June Sucker has a large, oblique mouth with smooth lips, and the Utah Sucker has a much smaller mouth with papillose lips (see above), it follows, assuming hybridism in the contemporary June

Sucker, that a moderately small and moderately oblique mouth (an intermediate condition) would have SUCKERS OF UTAH LAKE 23 greater papillosity than a very large and oblique mouth. Notwithstanding, the hmate mouth shown in Miller and Smith's (1981) fig. 7B appears smoother than the larger hippocrepiform mouths in figs. 7C and 9C.

Thus, the mouth of the putative example of mictus in fig. 7B is intermediate in shape but not in lip papillosity. Several more examples of morphologic non-intermediacy are revealed by internal traits of Utah

Lake suckers (Stubbs 1966). Non-intermediate attributes for the Webug Sucker or Chasmistes liorus mictus are inconsonant with the position of Miller and Smith (1981) that these forms are hybrids of the June and

Utah Suckers. Miller and Smith (1981: 17) affirmed that "The hybrid origin hypothesis... would be rejected if the characteristics of mictus were inconsistent with hybrid-like intermediacy between Chasmistes liorus and Catostomus ardens". Gel electrophoretic studies have demonstrated that a form that was presumed to be a hybrid of the Cui-ui (Chasmistes cujus) and Tahoe Sucker (Catostomus tahoensis) because of its intermediate mouth and head morphologies, is actually a variant of the Cui-ui (USFWS 1995: 3). This finding suggests that members of Chasmistes are pleomorphic or genetically polymorphic.

Stubbs (1966) attested that most external morphologic characters are ineffectual in differentiating the year-round catostotnid residents of Utah Lake. Examples are scale density and the number of fin rays (see above). Stubbs (1966: 7) affirmed that in distinguishing Utah Lake suckers, it is important to consider a complex of characters, internal as well as external. Seeking anatomies that would more efficaciously distinguish these fishes, Stubbs (1966: 8) investigated the Weberian mechanism because its features are unique in Catostomidae, and had been used to define specid'as well as higher-level taxa within the family.

He discovered that there are many interspecific differences in the configuration and size of the components of the Weberian mechanism. Stubbs (1966: 42, 52) found that intraspecific variability in the morphology of the Weberian mechanism is greatest in the relatively wide-ranging Utah Sucker and less in the Webug and

June Suckers which are endemic to the Utah Lake ecosystem. Conformations and sizes of the parts of the

Weberian mechanism are most constant in the Webug Sucker.

The Weberian mechanism comprises the pars audit= (auditory part) which indirectly connects the swim bladder to the membranous labyrinth of the inner ear, and the pars sustentaculum (support part). The latter constitutes the part of the anterior vertebral column that sustains and protects the pars auditum, and GREAT BASIN NATURALIST 24 provides an attachment for muscles extending from the caudal cranium, pectoral girdle, cranial swim bladder, and vertebral elements that are caudad to the pars sustentaculum. The pars auditum is composed of four paired ossicles, the claustra, scaphia, tripi, and intercalaria (Stubbs 1966: 9). Claustra (Latin, claustrum, gateway, or a bolt or bar that secures a gate) are patelliform ossicles measuring 5 2.2 by 5 3.0 mm that lie at the anterior gateway to the Weberian apparatus (see Stubbs 1966: 21, plate 2). They articulate with the anterodorsal facet of the first vertebral centrum and the anteroventral margin of the second neural arch. The claustrum bears an articular condyle which Stubbs (1966: fig. 30) depicted graphically as being relatively longest in the Webug Sucker. Scaphia, measuring <3.6 by < 5.0 mm, extend craniocaudally from the claustra to the intervertebral space between the first and the second (comprising the fused second and third) centra. The scaphium, which in Latin means concavity (e.g., vessel or basin), derives its name from its cyathiform concha stapedis which is shallower in the Utah Sucker than the Webug and June Suckers. The scaphium bears (1) a dentate dorsal process that inserts in connective tissue at the ventrolateral juncture of the second and third neural arches, (2) a relatively large, obtuse, and peg-like ventral process that projects almost perpendicularly from the medial surface of the concha to insert into deep pits on the dorsolateral surface of the first vertebral centrum, and (3) a meager, blunt posterior process (Stubbs 1966: 22-23). The dorsal process is very acute and attenuated in the June Sucker, caniniform in the Utah Sucker, and gently peaked in the Webug Sucker (Stubbs 1966: 22, 31, 37, plate 4). Contrary to Stubbs' (1966: plate 4) graphical depiction of scaphia bearing a very short ventral process in the Webug Sucker and a more prominent one in the June Sucker, the textual description of this ossicle (1966: 31) reveals that the ventral process is larger and blunter in the Webug Sucker. Despite its much shorter appearance graphically, the length of the ventral process in the Webug Sucker is 1.5 times the length of the dorsal process (Stubbs

1966: 22-23, fig. 31). In the Utah Sucker, the lengths of the two processes are approximately equal (Stubbs

1966: 37, fig. 22). From the posterior process which protrudes from the center of the lateral surface of each concha stapedis, an interossicular ligament passes to the anterior ramus of the tripus and provides an abode for the intercalarium (Stubbs 1966: 23). Fenestrated tripi measuring <7.5 by 5 18.6 mm, continue caudally and slightly ventrally from the dorsolateral surface of the first centrum to the mid-ventral part of the fifth SUCKERS OF UTAH LAKE 25 centrum (Stubbs 1966: 25, 32, 38). The tripus (three-foot: Latin tri-, three; Greek pous, foot) apparently derives its name from 3 of its parts: (1) anterior ramus, (2) posterior ramus, and the (3) articular process that protrudes from the body (the fourth part of the tripus) both dorsally and ventrally, but is continuous medially where it inserts into two dorsocaudally-directed grooves on the lateral surface of the third vertebral centrum (Stubbs 1966: 25, plate 4). Of particular significance are the interspecific differences in the configuration of the tripus from a lateral perspective. From this aspect, the rami are approximately horizontal in the Webug Sucker (Stubbs 1966: 26, fig. 32); the anterior ramus is markedly decurved (dorsally convex) in the June Sucker but recurved (dorsally concave) in the Utah Sucker; and the posterior ramus is recurved in the June Sucker but decurved in the Utah Sucker (Stubbs 1966: 33, 39, figs. 25, 34). The tripus possesses a dorsal fossa that is more craniad than caudad in position. In the Webug Sucker, the base of this scalene dorsal fossa lies near the origin of the dorsal articular process (Stubbs 1966: 25, fig. 28). The triangular dorsal fossa in the June Sucker is clearly distinguishable by its attenuated dorsal vertex which projects so far dorsally that it reaches well into the dorsal articular process (Stubbs 1966: 32, fig. 39). In the Utah

Sucker, the large, trapezoid dorsal fossa is differentiable because it protrudes cranially the greatest distance.

Ventrally, the tripi of the three year-round catostomids of Utah Lake can be discriminated easily. In the

Webug Sucker, there is a large, quadrangular ventral fossa that extends far into the posterior ramus, or two large fossae that are separated by a dividing brace that originates at the base of the ventral articular process

(Stubbs 1966: 25, fig. 27). The bulk of the irregular ventral fossa in the June Sucker is situated in the body but is considerably prolonged into the posterior ramus (though not as much as in the Webug Sucker) and extends well into the ventral articular process (this extension is not shown graphically) (Stubbs 1966: 32-33, fig. 38). Multiple small fossae exist craniad to the large ventral fossa of this species. In the Utah Sucker, the shallow, triangular, ventral fossa is restricted to an area at, and slightly craniad to, the base of the articular process (Stubbs 1966: 38, fig. 19). The articular process exists only slightly craniad to the midpoint of the tripus in the Webug Sucker, much closer to the tip of the anterior ramus than to the tip of the posterior ramus in the June Sucker, and very close to the tip of the anterior ramus in the Utah Sucker

(Stubbs 1966: 25, 33, 38, plate 4). The anterior ramus of the tripus, which is connected to the scaphium via GREAT BASIN NATURALIST 26 an interossicular ligament, is longest and most slender in the Webug Sucker (Stubbs 1966: 25-26, plate 4).

The base of the body of the intercalarium (intercalary ossicle) is embedded within or saddled over the mid-ventrocaudal portion of that ligament. Intercalaria measure <2.6 mm in length, and consist of a proximal body or manubrium (Latin, handle or haft) and a distal shaft that may bear a dorsal flange (Stubbs

1966: 24). In the Webug Sucker, the intercalarium is a blocked ell whose caudal (outside) angle is almost perpendicular; this ossicle is broadly crescentic in the June Sucker and distinctively falcate in the Utah

Sucker (Stubbs 1966: plate 4). The shaft ascends from the manubrium to embed in the fibrous connective tissue covering the dorsolateral surface of the second vertebral centrum (Stubbs 1966: 24). Of systematic importance, according to Stubbs (1966: 38), the shaft in the Utah Sucker uniquely lacks a dorsal flange.

Distally, the shaft of the June Sucker is cochlear (spoon-shaped) (Stubbs 1966: 32).

With regard to the pars sustentaculum of the Weberian mechanism, the anatomy of vertebra 2 is interspecifically discriminating. Its neural arch, isolated from the corresponding centrum, is scutiform in the

Webug Sucker, ephippioid (saddle-shaped) in the June Sucker, and lachrymiform in the Utah Sucker (Stubbs

1966: 15, 28-29, 34-35, plates 1-2). In the Webug Sucker, dorsal ribs (also called transverse processes) that are proximally wide, project laterally from centrum 2 and also slightly dorsocaudally, becoming flattened and cultriform distally (Stubbs 1966: 15, plates 1-3). Two tiny apophyses on the proximal anterodorsal margin of the dorsal rib project medially to the mid-lateral surface of centrum 1 (Stubbs 1966: 15). The ventral surfaces of dorsal ribs in the Webug Sucker are broadly joined medially with the ventral (pleural) ribs of vertebra 2. Vertebra 3 lacks dorsal or ventral ribs (Stubbs 1966: 16). The pleural ribs of vertebrae

2 and 4 fuse in all 3 catostomids to form large wings (Stubbs 1966: 16, 29, 35, plates 1-3). The distance between the extremities of the dorsal ribs in the Webug Sucker is short, averaging .-.. 2/3 the width of its relatively squat 4th pleural ribs (Stubbs 1966: 16, plates 1-3). Dorsal ribs of the June Sucker are much more dorsocaudally angled than those of the Webug Sucker, and the distance between their extremities is much greater, averaging >90% of the distance between the termini of the 4th pleural ribs (Stubbs 1966: 16, plate

3). In this species, the dorsal rib is substantially fused ventrally with pleural rib 2, and the latter is joined with pleural rib 4 (Stubbs 1966: 29, plate 3). The configuration of the Utah Sucker's dorsal ribs (projecting SUCKERS OF UTAH LAKE 27 laterad and only slightly caudad) and the distance between their extremities (X ..--.- 84% of the extreme width of the pleural ribs) is intermediate (Stubbs 1966: 35). Its dorsal ribs, in contrast to those of the other 2 suckers, are not as broadly fused with the 2nd pleural ribs, and the 2nd and 4th pleural ribs are not as extensively joined. In all 3 taxa, the pleural ribs of vertebra 2 extend laterally but also ventrocaudally and do not join medially on the ventral surface of centrum 2 (Stubbs 1966: 16, 31, 45). Contrariwise, pleural ribs of vertebra 4 fuse medially to form a transverse plate which lies ventrad to the mid-ventral surface of centrum 4 in the Webug and June Suckers but ventrad to the cranioventral portion of centrum 4 in the Utah

Sucker (Stubbs 1966: 20, 31, 36). From pyramidal cavities in the dorsolateral surfaces of centrum 4, pleural ribs extend ventrolaterally in the Utah and Webug Suckers but ventrocaudally in the June Sucker (Stubbs

1966: 19-20, 30-31, 36, plates 1-3). Prominent ridges exist on the pleural ribs except in their craniad portion. The mean distance between the distal extremities of the 4th pleural ribs = 11.35% of mean BL in the Webug Sucker, 11.64% in the Utah Sucker, and 11.78% in the June Sucker (Stubbs 1966: derived from tables 1-4). The massive neural spine complex of vertebra 3 projects caudad and is cultriform dorsally

(Stubbs 1966: 17). Overall, it is scapuloid and caudally acute in the Webug Sucker, sagittate in the June

Sucker, and broadly sagittate in the Utah Sucker (Stubbs 1966: plates 1-2). In the Webug Sucker this complex is relatively short, extending caudad to a point midway between neural spines 6 and 7; it continues caudally to the apex of neural spine 7 in the June and Utah Suckers (Stubbs 1966: 17, 29, 35).

June Sucker Chasmistes liorus (smooth-bordered yawner, in reference to its large, oblique gape with lips devoid of papillae: Latin Bo, to smooth [Greek leios, smooth]; Greek oros, border or margin). As Jordan

(1878b: 219-220) explained in an addendum, the form described under the rubric of Chasmistes fecundus on pages 150-151 of the same treatise, is actually C. liorus. There are 37-53 (X --:--; 44) gill rakers on the first branchial arch of the June Sucker (Miller and Smith 1981: see table 3). In males, the anal fin and the lower lobe of C are tuberculate (Jordan and Gilbert 1881). The parietal fontanelle is very large (Jordan 1878b,

Jordan and Gilbert 1882, Jordan and Evermann 1896a). Other traits of the June Sucker are compared with those of other year-round catostomids of Utah Lake in the section on the Webug Sucker (see above). SUCKERS OF UTAH LAKE 27 laterad and only slightly caudad) and the distance between their extremities (X 84% of the extreme width of the pleural ribs) is intermediate (Stubbs 1966: 35). Its dorsal ribs, in contrast to those of the other 2 suckers, are not as broadly fused with the 2nd pleural ribs, and the 2nd and 4th pleural ribs are not as extensively joined. In all 3 taxa, the pleural ribs of vertebra 2 extend laterally but also ventrocaudally, and do not join medially on the ventral surface of centrum 2 (Stubbs 1966: 16, 31, 45). Contrariwise, pleural ribs of vertebra 4 fuse medially to form a transverse plate which lies ventrad to the mid-ventral surface of centrum 4 in the Webug and June Suckers but ventrad to the cranioventral portion of centrum 4 in the Utah

Sucker (Stubbs 1966: 20, 31, 36). From pyramidal cavities in the dorsolateral surfaces of centrum 4, pleural ribs extend ventrolaterally in the Utah and Webug Suckers but ventrocaudally in the June Sucker (Stubbs

1966: 19-20, 30-31, 36, plates 1-3). Prominent ridges exist on the pleural ribs except in their craniad portion. The mean distance between the distal extremities of the 4th pleural ribs = 11.35% of mean BL in the Webug Sucker, 11.64% in the Utah Sucker, and 11.78% in the June Sucker (Stubbs 1966: derived from tables 1-4). The massive neural spine complex of vertebra 3 projects caudad and is cultriform dorsally

(Stubbs 1966: 17). Overall, it is scapuloid and caudally acute in the Webug Sucker, sagittate in the June

Sucker, and broadly sagittate in the Utah Sucker (Stubbs 1966: plates 1-2). In the Webug Sucker this complex is relatively short, extending caudad to a point midway between neural spines 6 and 7; it continues caudally to the apex of neural spine 7 in the June and Utah Suckers (Stubbs 1966: 17, 29, 35).

June Sucker Chasmistes liorus (smooth-bordered yawner, in reference to its large, oblique gape with lips devoid of papillae: Latin ho, to smooth [Greek leios, smooth]; Greek oros, border or margin). As Jordan

(1878b: 219-220) explained in an addendum, the form described under the rubric of Chasmistes fecundus on pages 150-151 of the same treatise, is actually C. liorus. There are 37-53 (X -Az 44) gill rakers on the first branchial arch of the June Sucker (Miller and Smith 1981: see table 3). In males, the anal fin and the lower lobe of C are tuberculate (Jordan and Gilbert 1881). The parietal fontanelle is very large (Jordan 1878b,

Jordan and Gilbert 1882, Jordan and Evermann 1896a). Other traits of the June Sucker are compared with those of other year-round catostomids of Utah Lake in the section on the Webug Sucker (see above). GREAT BASIN NATURALIST 28

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Sucker larvae and early juveniles. Contribution 37 of the Larval Fish Laboratory, Colorado State

University, Fort Collins. Publication No. 88-8, Utah Department of Natural Resources, Division of

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SNYDER, J. 0. 1916. Notes on a collection of fishes made by Dr. Edgar A. Mearns from rivers tributary

to the Gulf of California. Proceedings of the United States National Museum 49: 573-586 + plates 76

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---. 1922. Notes on some western fluvial fishes described by Charles Girard in 1856. Proceedings of the

United States National Museum 59: 23-28. GREAT BASIN NATURALIST 34

STUBBS, W. J. 1966. The Weberian osteology of three Utah Suckers (Catostomidae). Unpublished master's

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U.S. FISH AND WILDLIFE SERVICE. 1995. Recovery plan for June Sucker (Chasmistes liorus): draft.

Utah Department of Natural Resources, Division of Wildlife Resources, for Region 6, U.S. Department

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UTAH LAKE FISH MANAGEMENT ADVISORY TEAM. 1994. Overview of Utah Lake fish management

studies: draft. Unpublished report. Utah Department of Natural Resources, Division of Wildlife

Resources, Salt Lake City. 52 pp. FIGURE LEGENDS

Fig. 1. Pantosteus (= Catostomus) platyrhynchus. From Cope and Yarrow (1876: Plate 29, Fig. 3).

Fig. 2. Catostomus ardens. From Evermann (1893: Plate 18, Fig. 3).

Fig. 3. Catostomus ardens. From Jordan and Evermann (1900: Plate 34, Fig. 84).

Fig. 4. Catostomus (= Chasmistes) fecundus. From Cope and Yarrow (1876: Plate 32, Fig. 1).

Fig. 5. Catostomus fecundus. From Cope and Yarrow (1876: Plate 32, Fig. lb).

Fig. 6. Chasmistes liorus. From Jordan and Evermann (1900: Plate 34, Fig. 85).