A Review of the North American Freshwater Snail Genus Pyrgulopsis

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14 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY SPECIES OF QUESTIONABLE STATUS.—Hoyia sheldoni, from Lake Michigan, also may belong in Pyrgulopsis as its shell is closely similar to eastern members of this genus. Unfortunately, only dry shells, albeit live-collected, were available for this species and details discernable from resuscitated animals were not sufficient to confidently assess the status of this taxon. I also have been unable to obtain material for assessment of generic identity of Amnicola yatesiana, which may have lived in the San Joaquin Valley, California, during recent times (Taylor, 1981) and which has been allocated to Savaginius (see Appendix 2). Western American Species Pyrgulopsis aardahli Hershler, 1989 Pyrgulopsis aardahli Hershler, 1989:179, figs. 10-14. DIAGNOSIS.—Shell ovate to broadly conical, medium-sized, umbilicate. Penial filament short, lobe very small. Penial ornament a weak, dot-like Dgl; small, circular terminal gland; and stalked ventral gland. DESCRIPTION.—Shell (Figure la) ovate to broadly conical; height, 2.6-3.4 mm; whorls, 4. Protoconch very weakly punctate. Teleoconch whorls convex, slightly shouldered; sculpture of faint growth lines. Aperture ovate, narrowly adnate to or slightly separated from body whorl. Inner lip complete, medium thickness; columellar lip very slightly reflected. Outer lip slightly prosocline. Umbilicus rimate to open. Periostracum light brown. Operculum (Figure lb,c) broadly ovate, light amber; nucleus slightly eccentric; dorsal surface strongly frilled. Attachment scar margin well thickened all around (broadly so along most of perimeter). Callus well developed. Central radular tooth (Figure 32a) with moderately indented dorsal edge; lateral cusps, S; central cusp rounded, considerably broader and slightly longer than laterals; basal cusps, 1, short, narrowly triangular, with moderate dorsal support. Basal process broad; basal sockets deep. Lateral margins thickened; neck weak. Snout dark gray-black; neck variably pigmented. Cephalic tentacles pale other than a light gray patch proximal to eyespots. Pigment sometimes concentrated along anterior edge of foot and margins of opercular lobe. Pallial roof, visceral coil dark brown-black. Ctenidial filaments, 23, tall, broad. Osphradium elongate (33%), centered well posterior to middle of ctenidial axis. Kidney opening white. Stomach caecum finger-like. Testis, 1.5 whorls, overlapping stomach to edge of style sac. Prostate gland bean-shaped to near-circular, pallial section short. Pallial vas deferens weakly kinked proximally. Penis (Figure 43a) large, extending slightly beyond mantle edge; filament short, narrow, tapering; lobe short, narrow (sometimes absent). Dgl dot-like, sometimes absent, positioned near mid-line. Terminal gland small, circular-transverse, borne on ventral surface distally (sometimes absent). Ventral gland large, elongate, borne on prominent swelling. Proximal penial filament with dark internal pigment. Ovary, 1 whorl, overlapping posterior stomach. Pallial albumen gland short. Capsule gland slightly shorter than albumen gland. Genital aperture a broad terminal slit with very short vestibule. Coiled oviduct a short horizontal twist overlapping a near circular loop. Oviduct and bursal duct join just behind pallial wall. Bursa copulatrix ovoid, medium length and width, with about 50% of length posterior to albumen gland. Bursal duct narrow, slightly shorter than bursa copulatrix, partly embedded in albumen gland anteriorly. Seminal receptacle finger-like, usually folded, short, overlapping bursal duct. TYPE LOCALITY.—Spring, Bramlette Ranch, Benton Valley, Mono County, California (T IS, R 32E, SW1/4 sec. 6). Holotype, USNM 860406; paratypes, USNM 857951. DISTRIBUTION.—Known only from type locality, upper Owens River drainage. REMARKS.—Amongst members of the group of closely similar species living in Owens Valley, California, this snail resembles P. giulianii in having a penis with highly reduced lobe and small, circular terminal gland. It differs in having a kinked pallial vas deferens and seminal receptacle positioned lateral to the ventral edge of the albumen gland. MATERIAL EXAMINED.—USNM 857951 (paratypes).
NUMBER 554 15 FIGURE 7.—Western Pyrgulopsis: a-c, P. aardahli (a, holotype, USNM 860406.3.3 mm; b, c, opercula, USNM 857951. bars = 0.45 mm, 0.42 mm); d-f, P. amargosae (d, holotype, USNM 860401, 2.3 mm; e,f, opercula, USNM 857972, bars = 0.29 mm, 0.3 mm).
Page 1 and 2: A Review of the North American Fres
Page 3 and 4: S M I T H S O N I A N C O N T R I B
Page 5 and 6: Contents Page Introduction 1 Materi
Page 7 and 8: A Review of the North American Fres
Page 9 and 10: NUMBER 554 position of coiled ovidu
Page 11 and 12: NUMBER 554 field work and laborator
Page 13 and 14: NUMBER 554 FIGURE 2.—Morphology o
Page 15 and 16: NUMBER 554 Sr Ag Dsr FIGURE 4.—Di
Page 17 and 18: NUMBER 554 11 studied the anatomy o
Page 19: NUMBER 554 13 contrasted the genus
Page 23 and 24: NUMBER 554 17 Pyrgulopsis amargosae
Page 25 and 26: NUMBER 554 19 (in T 3S, R 22E, 25,0
Page 27 and 28: NUMBER 554 21 Pratt (1977) recorded
Page 29 and 30: NUMBER 554 23 DISTRIBUTION.—This
Page 31 and 32: NUMBER 554 25 nucleus slightly ecce
Page 33 and 34: NUMBER 554 27 FIGURE 11.—Western
Page 39 and 40: NUMBER 554 33 ornament an elongate,
Page 41 and 42: NUMBER 554 35 dium centered slightl
Page 43 and 44: NUMBER 554 FIGURE 15.—Western Pyr
Page 45 and 46: NUMBER 554 Pyrgulopsis glandulosa H
Page 47 and 48: NUMBER 554 41 visceral coil black.
Page 53 and 54: NUMBER 554 copulatrix. Seminal rece
Page 55 and 56: NUMBER 554 Pyrgulopsis merriami (Pi
Page 59 and 60: NUMBER 554 or lightly pigmented on
Page 61 and 62: NUMBER 554 weakly frilled. Attachme
Page 63 and 64: NUMBER 554 lake have not yielded li
Page 65 and 66: NUMBER 554 59 REMARKS.—The small
Page 69 and 70: NUMBER 554 63 units; Dg3 small (som
Page 71 and 72:
NUMBER 554 65 Pyrgulopsis simplex H
Page 73 and 74:
NUMBER 554 67 FIGURE 26.—Western
Page 75 and 76:
NUMBER 554 69 DIAGNOSIS.—Shell ov
Page 77 and 78:
NUMBER 554 71 filament, extending s
Page 79 and 80:
NUMBER 554 FIGURE 28.—Eastern Pyr
Page 81 and 82:
NUMBER 554 75 medium length, obliqu
Page 83 and 84:
NUMBER 554 77 2e). Visceral coil li
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NUMBER 554 FIGURE 30.—Eastern Pyr
Page 87 and 88:
NUMBER 554 ANSP 61606; paralectotyp
Page 89 and 90:
NUMBER 554 83 and southeastern Ariz
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Appendix 2 Fossil Species Described
Page 93 and 94:
NUMBER 554 87 Pyrgulopsis bryantwal
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NUMBER 554 89 FIGURE 32.—Central
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NUMBER 554 FIGURE 34.—Central rad
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NUMBER 554 FIGURE 38.—Central rad
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NUMBER 554 FIGURE 44.—Penes of we
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NUMBER 554 FIGURE 52.—Penes of ea
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Abbott, R.T. 1948. A Potential Snai
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NUMBER 554 Society of Washington, 1
Page 121:
NUMBER 554 115 gyrus, Gabbia, Hydro
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A Review of the North American Freshwater Snail Genus Pyrgulopsis

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