Comprehensive Description
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Inglês
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fornecido por Smithsonian Contributions to Zoology
Alasmidonta (Pressodonta) viridis (Rafinesque, 1820)
Unio viridis Rafinesque, 1820:293. [Type-locality: Ohio River, Kentucky River, and small rivers adjacent to the Kentucky River. Original material lost; neotype selected herein. See remarks.]
Unio calceolus Lea, 1830:265, pl. 3: fig. 1. [Type-Locality: “Ohio.” The lectotype (Lea's figured specimen), herein selected, is in the Smithsonian Institution collection of mollusks (USNM 86261) and is labelled “Ohio.”]
Alasmidonta truncata Conrad, 1835:73. [A nomen nudum credited by Conrad to Say, with Unio calceolus Lea declared as a synonym. Say never published the name, however, so Conrad is its author and it is an objective synonym of Unio calceolus Lea.]
Margaritana deltoidea Lea, 1838:43, pl. 13: fig. 38. [Type-locality: “Ohio River, near Cincinnati [and] Scioto [River].” The lectotype, herein selected, is Lea's figured specimen and is in the Smithsonian Institution collection of mollusks (USNM 86215); it is labelled “Scioto River, Ohio. Dr. Kirtland.”]
Calceola angulata Swainson, 1840:382. [Based on Lea's original figure of Unio calceolus and therefore an objective synonym of Unio calceolus Lea, 1827.]
Margaritana minor Lea, 1845:163 [Latin description and localities only]; 1848:82, pl. 8: fig. 26 [the same, with English description, remarks, and illustrations added]. Type-locality: “Tennessee [and] North Carolina.” The lectotype, herein selected, is Lea's figured specimen and is in the Smithsonian Institution collection of mollusks (USNM 86224); it is labelled “N.C. Budd.”]
Alasmidonta calceolus danielsi Baker, 1928:187, pl. 69: fig. 2; pl. 72: fig. 7–11. [Type-locality: “Moots Creek, White Co[unty], Ind[iana].” Holotype in the Museum of Natural History of the University of Illinois, catalog number Z-14301a (Franzen, 1956:27).]
Alasmidonta calceolus magnalacustris Baker, 1928:188; pl. 69: fig. 3; pl. 72: fig. 12–16. [Type-locality: “Sturgeon Bay, [Lake Michigan], Door Co[unty], Wis[consin].” Holotype in the Museum of The Wisconsin Geological and Natural History Survey, University of Wisconsin, catalog number 933A (Franzen, 1957:33).]
THE SHELL
DESCRIPTION.—Shell variable, ovate, subquadrate or subtriangular; up to 56 mm long, 36 mm high, and 23 mm wide (most specimens are much smaller); slightly thickened anteriorly (up to 3 mm thick) and slightly thinner posteriorly, but not fragile. Anterior margin semicircular and evenly rounded; ventral margin flatly curved, nearly straight, or somewhat concave posterior of center; posterior margin sharply rounded or bluntly pointed below and obliquely flattened (or slightly concave in some specimens) above; junction of posterior margin and dorsal margin angular; and dorsal margin rather short and broadly convex throughout or, in some specimens, concave anteriorly. Maximum inflation above the midline and at center of shell or at posterior ridge. Beaks not inflated, located about 28% to 33% of the distance from anterior to posterior, and projecting only a little above the hinge line in most specimens. Posterior ridge rounded (almost angular above in some specimens), quite prominent, somewhat inflated (especially above), and extending to the posterior point. Posterior slope rather narrow and flattened or concave near the margin. Growth increments marked by concentric low wrinkles and grooves and by clearly apparent lines of growth. Additional postjuvenile sculpturing consisting of an obscure radial ridge dorsal to the posterior ridge and, on some specimens, a few short, raised threads on the posterior slope perpendicular to the lines of growth. Periostracum somewhat glossy and yellowish brown with broad and narrow, wavy green rays. In some specimens the greenish rays are very wide leaving only narrow yellowish rays between them. Rays visible in adults as well as in juveniles. Ligament rather short, of moderate thickness, and brown to blackish.
Hinge teeth well-developed but quite small and incomplete. Pseudo-cardinal teeth stumpy or pyramidal, erect, serrated, irregular, buttressed below, and numbering 1 in the right valve and (in most specimens) 1 in the left, although in some specimens only a socket occurs in the left valve. Interdental projection in the left valve prominent, elevated, irregular, and confluent with the pseudocardinal tooth or even enveloping it and forming a single structure. Lateral teeth absent in most specimens, vestigial or moderately developed in others, and therein numbering 1 or 2 in the right valve and 2 in the left. Beak cavity hollowed out but shallow. Anterior muscle scars well impressed and prominent, pallial line lightly or strongly impressed, posterior muscle scars shallow but clearly defined and scars within beak cavity consisting of a few short, irregular, variable grooves on the back of the hinge plate and two shallow radial grooves extending anterior-ventrally and posterior-ventrally. Nacre shiny, whitish, with a bluish tinge posteriorly, and iridescent posteriorly. In some specimens a creamy suffusion extends over the central part of the shell.
Beak sculpture variable, moderately strong and composed of about 6 irregular, broad curved ridges that are gently convex or sinuate centrally (i.e. double-looped), sharply angled on the posterior ridge, and narrow, straight and crowded on the posterior slope and directed thereon back toward the umbonal apex. Beak sculpture may be seen even on most adult specimens.
VARIATION.—Alasmidonta viridis is morphologically more responsive to special habitat characteristics than any other species of its genus. Baker (1928:185–189) has shown that in Wisconsin the species attains its maximum size and thickness in large and medium-sized rivers. That is the morph described by Lea as Unio calceolus. In small creeks the species is much smaller, with a more obliquely truncated posterior. This is the morph that I believe was described in 1820 by Rafinesque as Unio viridis (see Remarks) and by Baker (1928:187) as Alasmidonta calceolus danielsi. Population samples representing the large stream morph and the small stream morph are shown in Table 5 from Little Miami River, Ohio and Mad Creek, Iowa respectively. Intermediate specimens occur in ecologically transitional localities (Baker, 1928: 188). Another ecophenotype (from large lakes) was described as such by Baker (1928:188) under the name Alasmidonta calceolus magnalacustris. This morph is more compressed and smaller than the small stream morph.
Baker has also asserted that the female is more inflated at the posterior ridge than the male in the large river morph and shorter than the male in the lake morph. This could not be confirmed from available material.
TOPOGRAPHIC ANATOMY
SPECIMEN DESCRIBED.—From Clear Fork, Mohican River, route 3 bridge, Hanover Township Ashland Co., Ohio, collected 25 May 1959 (OSUM 9656, D. H. Stansbery station 1959:57); preserved in 70% ethyl alcohol; shell length 31.9 mm, sex female (gravid).
DESCRIPTION—Mantle grayish white and covered with a fine reticulate pattern of small, pale, orange-white patches separated by grayish lines. Pallial muscles forming a grayish band and adductor muscles orange. A broken band of dark pigment runs along the edge of the mantle from the posterior ventral region to the dorsal end of the supra-anal opening. Incurrent opening 7 mm long and surrounded within the edge (and separated from the edge by a narrow lip) by densely-packed, small, round papillae; those on the inner row the longer (about 1.0 mm long and 0.2 mm wide at the base). Separation of incurrent and anal openings apparently achieved entirely by the diaphragm, although this cannot be fully determined from preserved specimens. Anal opening about 4 mm long, separated from the mantle edge by a lip, and surrounded at the edge by a single row of tiny papillae (about 0.2 mm long and 0.1 mm in diameter at the base). Mantle connection short (1.5 mm) between anal and supra-anal opening. Supra-anal opening narrow, long (7.5 mm), and without papillae.
Outer gravid demibranch of preserved specimen pale brown and inner demibranch pale yellowish brown. Outer demibranch 20 mm long, 8 mm high, 2 mm thick, pad-like, truncated posteriorly, gradually and irregularly curved ventrally, and with margin rising in a flattened curve to an acutely rounded anterior-dorsal apex. The outer tissue has about 10 radial double filaments per mm and 5 cross filaments and the underlying water tubes number 3.0 per mm. Inner demibranch 21 mm long, 9 mm high, irregularly truncated posteriorly, ventral margin flattened, anterior margin diagonally truncated, and projecting beyond the outer demibranch, especially so (4 mm) anterior-ventrally. Outer tissue with about 10 radial double filaments per mm and 5 cross filaments; water tubes about 3 per mm and every fourth water tube is wider than the rest. The inner lamina of the inner demibranch is not attached to the visceral mass. The diaphragm is open posterior to the visceral mass because the inner laminae of the inner demibranchs are not fused there; it is also sharply ridged and perforated by the ends of the water tubes.
Labial palps long-triangular; barely touching the inner demibranchs; with flatly-sigmoid ventral margin; short, straight dorsal margin; and rounded, centrally located, distal point. The outer surfaces are smooth and the inner appressed surfaces are deeply furrowed (about 6 furrows per mm at the margin). The outer palpus is attached to the mantle for about 5/6 of its length and the free ends of the palpi are subdorsally attached to each other for only 1/4 of their lengths.
The demibranchs in the gravid female specimens from the Mohican River vary in length from 55% to 63% and in width from 25% to 33% of the shell length (13 specimens). The non-gravid specimens that are presumed to be females have outer demibranchs that measure: length, 56% (both) and height 22% and 24% shell length. The presumed male has outer demibranchs that measure: length 61% and height 21% of shell length. Inner demibranchs gave the following measurements in terms of shell length: length 61% to 69%, height 28% to 35% for gravid females; length 60% and 63%, height 27% and 29% for non-gravid females; and length 64%, height 26% of shell length for the single male.
It is of interest that the population sample from Mohican River contained 15 females and only 1 male. Although hermaphroditism might be expected in a headwater species such as Alasmidonta viridis, no hermaphrodites were found among 86 sectioned specimens of it reported by van der Schalie (1970). Of course population differences in sexuality may occur.
VARIATION.—Table 6 shows that in the available material most of the observed anatomical features are variable. According to Ortmann (1912:295–6), who then had only two specimens, the mantle connection between the anal and supra-anal openings (A-SA) is almost as long as the anal opening (A), the supra-anal (SA) is only slightly longer than A-SA, the anal opening is crenulate, and the labial palps do not touch the inner demibranch. Table 6 indicates that the relative lengths of A, A-SA, and SA are variable in the Mohican River specimens and that the labial palps overlap the inner demibranchs, or touch them, in many specimens. The anal opening in this species is finely papillate with a single row of short papillae from 0.1 to 0.6 mm long.
Ortmann (1912, 1914) has also shown that the extent to which the inner lamina of the inner demibranch is connected to the visceral mass is variable. Holston River specimens that he examined had the inner lamina completely connected to the visceral mass; in some Clinch River specimens it was almost entirely connected and in others it was only partly connected; and in two Cumberland River specimens it was entirely unconnected. The Mohican River specimens recorded in Table 6 all exhibited the entirely unconnected condition.
GLOCHIDIUM
DESCRIPTION.—Glochidium short pyriform, 0.232 mm high, 0.286 mm long (parallel to hinge axis), and 0.086 valve convexity (each valve). The posterior margin is more fully rounded and more protuberant than the anterior and the apices are located slightly anteriorly of center (about 47% of the distance from anterior to posterior). The surface is finely malleated (depressions subcircular and about 3 to 8 μm wide) and even more finely pitted. A narrow area near the apex and the ventral margin is without malleations or pits and is sculptured with fine, concentric lines. The hinge is markedly concave and about 0.205 mm long. Ligament narrow and hidden at both ends by the expanded edges of the shell.
Each apical stylet is flatly recurved and bent inward, and is apparently about 70 μm long, 25 μm wide at the base, and very gradually narrowing to the apex (obscure in our partially open material). The stylets are supported on each side, for what appears to be about half its length, by a broad membrane, an expanded portion of the membrane that projects inward from the entire edge of each valve. Each stylet is covered in its exposed surface by parallel radial rows (about 4 rows near the base narrowing to about 2 rows toward the apex) of large microstylets, each about 10–12 μm long. The microstylets are principally subcircular in cross-section but with low, radial angulations. (The angulations are not acute as in A. undulata or A. marginata). On the base of the stylet the microstylets become gradually smaller and on the outer surface of the apex, and on the supporting membrane near the stylet, they are very small (<0.5 μm) and numerous.
The above description is of a glochidium (specimen B) from an adult mussel collected on 25 April 1959 from Clear Fork Mohican River, Hanover Township, Ashland Co., Ohio by D. H. Stansbery (OSUM 9656). Two other glochidia from the same adult have the following measurements: (specimen A) length 0.286 mm, height 0.235 mm, single valve convexity 0.089 mm; (specimen C) length 0.292 mm and width 0.232 mm. The hinge line of specimen A is approximately straight and that of specimen C is slightly concave (but not as concave as specimen B). The glochidia valves could not be opened completely so details of stylet morphology are still obscure.
The material available does not, of course, indicate the extent of morphological variation in the glochidia of A. viridis. Distinctive features are the relatively small size (length about 0.286 to 0.292 μm), height substantially less than length (about 80% of length), a tendency for the hinge to be concave, and a narrow stylet that has only a few (about 4 narrowing to 2) longitudinal rows of major microstylets.
LIFE HISTORY
GRAVID PERIOD.—Baker (1928:186) gives “Probably bradytictic, with mature glochidia in the fall (September).” The gravid specimen from Mohican River described above was collected on 25 April 1959 by D. H. Stansbery. A gravid period at least from September to late April is indicated but more data are surely desirable.
NATURAL HOSTS.—J.P.E. Morrison (in Clarke and Berg, 1959) has reported that Etheostoma nigrum Rafinesque (johnny darter) and Cottus bairdi Girard (mottled sculpin) are natural hosts for A. viridis.
HABITAT—“In creeks, the usual habitat of this species, calceolus [=viridis] burrows down into the sand or gravel, locating itself either in the riffles or in the pools. Occasionally, it occurs in mud along the banks. In the larger parts of the [Huron] river it occurs sparsely on sand and gravel. A few abnormally large specimens were taken from a sandy mud substratum in [a] ponded area…It is evident that…this species follows Ortmann's law—a law to the effect that certain species tend to become more obese as the size of the stream in which they live increases” (van der Schalie, 1938: 58–59).
Baker (1928:186), describing the habitat of the typical morph, writes: “Usually borrowing in streams on a sand bottom in shallow water. Also on lake shores on a sand bottom. In Sturgeon Bay [Wisconsin] on a sandy-clay bottom in 1–1.1 m of water.” For the small stream morph he gives (1928:188) the substrate as pebbles, gravel, or sand and the depth as 0.2 to 0.7 m or “shallow water,” and adds: “The usual habitat is in sand buried from sight.”
GEOGRAPHICAL RECORDS
GREAT LAKES–ST. LAWRENCE SYSTEM.—Lake Michigan Drainage: Pensaukee River, Abrams, Oconto Co., Wisc. (ANSP, USNM, MCZ). Crystal River, Waupara Co., Wisc. (MCZ). Lake Michigan shore near Milwaukee, Milwaukee Co., Wisc. (ANSP, USNM). Augusta Creek, 2 mi (3.2 km) NE of Midland Park, Kalamazoo Co., Mich., (1960, F. W. Grimm! (NMC)). Grand River, 6 mi (9.6 km) S of Jackson, Jackson Co., Mich. (NMC). Mud Creek, Phillips Road, 2 mi (3.2 km) N of Mason, Ingham Co., Mich. (1960, F. W. Grimm! (NMC)). Grand River, Lansing, Ingham Co., Mich. (ANSP). Bear Creek, Kent Co., Mich. (MCZ). Grand Rapids, Kent Co., Mich, (ANSP, USNM). Bear Lake, Muskegon Co., Mich. (USNM). Clam River, Lake Township, Missaukee Co., Mich. (OSUM). Crockery Creek, Ottawa Co., Mich. (USNM).
Lake Huron Drainage: Maitland River, Auburn, Huron Co., Ont. (NMC). Schoolcraft Lake, Grayling, Crawford Co., Mich. (ANSP). Lake Graylings, Crawford Co., Mich. (ANSP). South Branch, Tobacco River, at bridge just S of Farwell, Clare Co., Mich. North Branch, Chippewa River, Isabella Co., Mich. Prairie Creek, Hwy. 21 bridge, 1 mi (1.6 km) E of Ionia, Saginaw Co., Mich., (all 1966, C. B. Stein! (OSUM)). Saginaw River, Mich. (ANSP). Black River near Lexington, Sanilac Co., Mich. (USNM).
Lake St. Clair Drainage: Medway Creek, 5 mi (8.0 km) N of Arva, Middlesex Co., Ont. (NMC). Sydenham River, 0.5 mi (0.8 km) NNE of Coldstream, Middlesex Co., Ont. (1971, A. H. Clarke and L. R. Clarke! (NMC), empty shells). Thames River, Mitchell, Perth Co., Ont. (ANSP, MCZ).
Lake Erie Drainage: Union Lake, near Pontiac, Oakland Co., Mich. (USNM). Honey Creek, W of Ann Arbor, Washtenaw Co., Mich. (NMC). Huron River, Ann Arbor, Mich. (MCZ). Fleming Creek, Parker's Mill Station, about 5 mi (8.0 km) E of Ann Arbor, Mich. (1965, H. B. Herrington! (NMC)). Stony Creek, Monroe Co., Mich. (OSUM). St. Joe River, Hudson, Lenawee Co., Mich. (USNM). Ten Mile Creek, Sylvania, Lucas Co., Ohio (MCZ). Cedar Creek, Hwy. 6, E edge of Waterloo, De Kalb Co., Ind. (1969, D. H. Stansbery, C. B. Stein! (OSUM), empty valves). Tymochtee Creek, Hwy. 37, 0.1 mi (0.2 km) SW of Marseilles Township, Wyandot Co., Ohio (1971, R. E. Bowers! (OSUM)). Tymochtee Creek near Brownstone, Wyandot Co., Ohio (1971, R. E. Bowers! (OSUM)). Little Sandusky River near Upper Sandusky, Wyandot Co., Ohio (OSUM). West Branch Huron River near Willard, Huron Co., Ohio (1969, R. E. Bowers! (OSUM)). Grand River, 2.6 mi (4.2 km) NE of Dundalk, Dufferin Co., Ont. (1971, B. T. Kidd! (NMC); also 20 other lots from various localities in Grand River system collected by B. T. Kidd in 1971). Cox Creek, 0.6 mi (1.0 km) SE of Bethany Church, Wellington Co., Ont. (1971, B. T. Kidd! (NMC)). Irvine Creek, 3 mi (4.8 km) N of Fergus, Nichol Township, Wellington Co., Ont. and 3 other Irvine Creek localities (1971, B. T. Kidd! (NMC)). Eramosa Branch, Speed River, Guelph, Wellington Co., Ont. (1965, C. B. Stein! (OSUM); 1966, J. G. Oughton! (NMC); also 7 other Speed River lots (NMC)). Conagagique Creek tributary, 0.2 mi (0.3 km) N of Floradale, Waterloo Co., Ont. (1971, B. T. Kidd! (NMC)). Nith River, 100 yds (91 m) upstream from CNRR bridge, Blenheim Township, Oxford Co., Ont. (1971, B. T. Kidd! (NMC)).
Lake Ontario Drainage: West Branch, upper Niagara River, W of Beaver Island State Park, [Niagara Co.], N.Y. (MCZ). Dufferin Island, Niagara River, Ont. (USNM, worn valve). Old Erie Canal, Monroe Co., N.Y. (Robertson and Blakeslee, 1948). Beaver Creek, Warren, Herkimer Co., N.Y. (MCZ). Tonawanda Creek, N.Y. (MCZ). Oriskany Creek, Oriskany Falls, Oneida Co., (Clarke and Berg, 1959).
OHIO RIVER SYSTEM.—Muskingum River Drainage, Ohio: Lake Fork, Licking River, Hwy. 661, 2.2 mi (3.5 km) S of Homer, Licking Co. (1975, R. Jezerinac! (OSUM)).
Scioto River Drainage, Ohio: Whetstone Creek above McKibben Road, Gilead Township, Morrow Co. (1962, D. H. Stansbery and C. B. Stein! (OSUM)). Big River at Hwy. and 37 bridge, 5 mi (8.0 km) ESE of Delaware, Delaware Co. (1969, D. H. Stansbery! (OSUM)). Shaw Creek, Canaan Township, Morrow Co. (1962, D. H. Stansbery and C. B. Stein! (OSUM)). Alum Creek near Columbus, Frankin Co. (MCZ). Scioto River, Columbus (ANSP), and Chillicothe, Ross Co. (USNM). Yellowbud Creek near Circleville, Pickaway Co. (OSUM). Big Darby Creek, Hwy. 40 bridge, Prairie Township, Franklin Co. (1957, D. H. Stansbery! (OSUM)). Little Darby Creek: just S of Union Co., Pike Township, Madison Co. (1965, C. B. Stein!); above Hwy. 40 bridge, West Jefferson, 11.0 mi (17.6 km) ENE of London, Madison Co. (1976, D. H. Stansbery!); and 3 other 1978 Little Darby Creek localities (all OSUM). North Fork, 6 mi (9.6 km) SE of Midway, Madison Co. (1967, K. A. Jennings and R. L. Hughes, Jr.! (OSUM)). Cloudy Creek, headwaters of River Styx, Hwy. 118, NW of Wadsworth, Medina Co. (1957, D. Myer! (OSUM)). Paint Creek, Rt. 165 bridge, 3 mi (4.8 km) SSW of Good Hope, Fayette Co. (1967, K. A. Jennings and R. L. Hughes, Jr.! (OSUM)). Sugar Creek, Concord/Union Townships, Fayette Co. (OSUM).
Licking River Drainage, Kentucky: [Licking River], Falmouth, Pendleton Co. (1969, D. H. Stansbery! (OSUM); also MCZ).
Little Miami River Drainage, Ohio: Todd Fork Little Miami River between Clarksville and Morrow, Warren Co. (1977, E. Secora! (OSUM), one valve only but huge, 58.2 mm long, 38.2 mm high). East Fork Little Miami River, Blue Sky Park Road, 4.4 mi (7.0 km) NNE of Williamsburg, Clermont Co. (1973, J. M. Sears! (OSUM)). Cloverlick Creek just above mouth of Poplar Creek, 4 mi (6.4 km) SW of Williamsburg (1969, M. Trautman! (OSUM), very large, 53.0 mm long, 33.0 mm high, 23.8 mm wide). Little Miami River, Corwin, Telegraph Mill Bridge, Wayne Township, Warren Co. (1976, D. H. Stansbery! (OSUM)). Massie's Creek below falls, Cedarville Township, Green Co. (1958, G. Acker! (OSUM)).
Miami River Drainage, Ohio: Spring Creek, 4 mi (6.4 km) E of Piqua, Shelby Co. (1967, C. B. Stein! (OSUM)).
Kentucky River Drainage, Kentucky: Hanging Fork Creek, Lytle, Lincoln Co. (MCZ). Dix River, 5 mi (8.0 km) E of Stanford, Lincoln Co. (MCZ). Elkhorn Creek near Swallowfield, Franklin Co. (1950, H. D. Athearn! (MCZ)). Eagle Creek, Owen Co. (MCZ).
Harrods Creek Drainage, Kentucky: Harrods Creek at Hwy. 329 bridge, E of Prospect, Oldham Co. (1965, D. Bickel! (OSUM)) and at Rt. 1694 bridge just below mouth of Darby Creek, Oldham Co. (1966, C. B. Stein! (OSUM)).
Salt River Drainage, Kentucky: Salt Creek, Anderson Co. (1968, R. Jezerinac! (OSUM), empty shells). Rolling Fork Salt River, 1 mi (1.6 km) SW of Lebanon, Marion Co. (1958, W. J. Clench and J. Rosewater! (MCZ)). Floyds Fork Salt River, Hwy. 50 and 150 bridge, 3 mi (4.8 km) NNW of Mount Washington, Jefferson Co. (1965, D. Bickel! (OSUM), empty shells).
Green River Drainage, Kentucky: Russell Creek, Green Co. (USNM). Green River, 8 mi (12.8 km) S of Campbellsville, Taylor Co. (1958, W. J. Clench and J. Rosewater! (MCZ)) and Mumfordville, Hart Co. (1964, 1965, 1966, D. H. Stansbery! (OSUM)). Barren River (USNM) and Barren River, Hwy. 626 bridge, 9.5 mi (15.2 km) WNW of Bowling Green, Warren Co. (1969, D. H. Stansbery! (OSUM)). Nolin River, White Mills, 15 mi (24.0 km) ENE of Leitchfield, Hardin Co., (1964, C. B. Stein! (OSUM)).
Blue River Drainage, Indiana: Blue River near Fredericksburg, Washington Co. (1950, H. D. Athearn! (MCZ)).
Wabash River Drainage, Indiana: Wildcat Creek, Gray's Mill Burlington, Carroll Co. (USNM). Honey Creek, Russiaville, Howard Co. (USNM). Sixmile Creek, Blue River Township, Hancock Co. (1975, E. Secora! (OSUM)). Tippecanoe River, Delong, Fulton Co. (USNM). White River (USNM). Duck Creek, about 1 mi (1.6 km) N of Greensboro, Henry Co. (1975, E. Secora! (OSUM), empty shell). Wabash River (USNM).
CUMBERLAND RIVER SYSTEM.—Cumberland River Drainage: Cumberland River, Pineville, Bell Co., Ky. (Ortmann, 1914). Lynn Camp Creek of Laurel River, Corbin, Whitley Co., Ky. (MCZ). Stones River, Murfreesboro, Rutherford Co., Tenn. (MCZ). Harpeth River, 6 mi (9.6 km) S of Bellevue [sic, probably Bellsburg, Dixon/Cheatham Co.], Tenn. (ANSP). West Fork Red River at Bakers Mill, 7.6 mi (12.2 km) S of Pembroke, Christian Co., Ky. and 6.6 mi (10.6 km) WSW of Elkton, Todd Co., Ky. (both 1971, D. H. Stansbery! (OSUM)). Red River, Hwy. 161 bridge, 4 mi (6.4 km) NW of Barren Plain, Robertson Co., Tenn. (1969, D. H. Stansbery! (OSUM)).
TENNESSEE RIVER SYSTEM.—Powell River Drainage: Sheep Shank, Wallen Creek, Lee Co., Va. (MCZ).
Clinch River Drainage, Virginia: Clinch River, 1 mi (1.6 km) N of Tazewell, Tazewell Co. (USNM). Clinch River at Richland and at Cedar Bluff, both Tazewell Co. (Ortmann, 1914).
Holston River Drainage: Big Creek, Rogersville, Hawkins Co., Tenn. (MCZ). North Fork Holston River, Saltville, Smyth Co., Va. (Ortmann, 1914). Holston River, Tenn. (ANSP).
French Broad River Drainage, Tennessee: Big Pigeon River and French Broad River (both USNM).
Hiwassee River Drainage: Conasauga Creek, Monroe Co., Tenn. (ANSP, MCZ, OSUM).
Paint Rock River Drainage, Alabama: Larkin Fork, Paint Rock River, below county Rt. 27 bridge, 4.6 mi (7.4 km) SE of Francisco, Jackson Co. (1973, C. B. Stein and J. Frederick! (OSUM) and 1.5 mi (2.4 km) above its mouth, Jackson Co. (1966, D. H. Stansbery! (OSUM)). Estill Fork, Paint Rock River at ford, 2.9 mi (4.6 km) NNE of Estill Fork, Jackson Co. (1974, D. H. Stansbery and K. Borror! (OSUM)).
Elk River Drainage, Tennessee: Boiling Fork Creek, Cowan, Franklin Co. (ANSP, MCZ). Elk River, Estill Springs, Franklin Co. (USNM). Elk River, Hwy. 50, Marion Co., and 3 mi (4.8 km) W of Pelham, Grundy Co., Tenn. (both 1953, A. H. Clarke and L. R. Clarke! (NMC)).
Buffalo River Drainage: Buffalo River, Natchez Trace bridge, near Lapier, Lewis Co., Tenn. (1968, D. H. Stansbery and C. B. Stein! (OSUM), empty shell).
Duck River Drainage, Tennessee: Duck River below Dement Bridge, 1.8 mi (2.9 km) SE of Haley, Bedford Co. and near Tullahoma, Bedford Co. (both 1965, B. Isom and P. Yokley! (OSUM)); Shelbeyville, Bedford Co. (MCZ); and near Shelbeyville (1967, W. J. Clench and D. H. Stansbery! (OSUM)). East Rock Creek, 1.8 mi (2.9 km) NNE of Verona, Marshall Co. (1976, C. B. Stein! (OSUM)).
Main Tennessee River: Tennessee River, Jackson Co., Ala. (ANSP).
UPPER MISSISSIPPI RIVER SYSTEM.—Rock River Drainage, Illinois: Kents Creek, Winnebago Co. (MCZ). [Rock River], Rockford, Winnebago Co. (USNM).
Illinois River Drainage: Buelah Lake, near Mukwonago, Waukesha Co., Wisc. (USNM). [Kankakee River], South Bend, St. Joseph Co., Ind. (USNM). Tributary of Illinois River, Canton, Fulton Co., III. (ANSP). [Sangamon River], Athens, Menard Co., III.
Missouri River Drainage: Big Piney River, 7 mi (11.2 km) W of Licking at Hwy. 32 bridge, Texas Co., Mo. (1965, D. H. Stansbery! (OSUM)).
Meramec River Drainage: Old Mines Creek, Hwy. 21 bridge, 3.5 mi (5.6 km) W of Fertile, Washington Co., Mo. (1975, F. Schilling and H. Kemper! (OSUM)).
LOWER MISSISSIPPI RIVER SYSTEM.—White River Drainage, Missouri: Current River, Shannon Co. (MCZ) Jack's Fork, Shannon Co. (MCZ, USNM). Flat Creek near Flat Creek, Barry Co. (1974, W. H. Dieffenbach! OSUM)). James River, southern Green Co. (ANSP), 7 mi (11.2 km) NW of Ozark, Christian Co. (OSUM), Finley Creek, Linden, Christian Co. (1965, D. H. Stansbery! (OSUM)), and Galena, Stone Co. (MCZ).
Arkansas River Drainage, Missouri: Spring Creek, Lawrence Co.; Center Creek, Sarooxie, Jasper Co. (both 1964, W. H. Dieffenbach! (OSUM)). Shoal Creek, Lawrence Co. (1965, W. H. Dieffenbach! (OSUM)).
REMARKS
After much consideration I have become convinced that the well-known name Alasmidonta calceola (Lea, 1827) should be replaced by Alasmidonta viridis (Rafinesque, 1820), so I am following Morrison (1969) and Stansbery and Clench (1974), who recommended this change but who do not discuss the reasons for it.
Rafinesque's description is quite explicit. He calls attention to the small size, the obliquely truncate posterior, the heavy beak sculpturing, the buttressed pseudocardinal teeth (“dent…decurrente”), and aspects of distribution and ecology (Rare dans l'Ohio, plus commune dans le Kentucky et les petites riviers adjacentes”) which, taken together, appear to be characteristic of no other species. The phrases “de la longueur d'un pouce et demi au plus” [=the length is 1 1/2 pouce (about 38 mm) at the most] and “longueur 5/9, diameter 7/16, axe 1/3 de la largeur” [= length 5/9, diameter 7/16, and axis 1/3 of the width] are confusing, but in the early 19th century “length” was used to mean the distance from the umbone to the opposite margin, and was approximately equivalent to what is now called height. “Width” was equivalent to what is now called length.
The largest specimens of Alasmidonta “calceola” that I have seen are each 38 mm high and agree perfectly with the maximum height given by Rafinesque. One is labelled “Cincinnati, Ohio” (OSUM 8626a) and one is from Todd Fork, Little Miami River, between Clarksville and Morrow, Warren County, Ohio (OSUM 41257). Measurements of specimens from Little Miami River, Ohio (see Table 5) give ratios of H/L = 0.545–0.665 and W/L = 0.335–0.531. These are also in agreement with decimal equivalents of the ratios given Rafinesque (H/L = 0.56, W/L = 0.44). The meaning of “axe” (axis) is not clear, but it may refer to the length of the ligament and, if so, that measurement is also correct.
The identity of Unio viridis Rafinesque has been the subject of controversy for many years and I regret that the issue must be resurrected. Vanatta (1915) and Frierson (1915) both discussed a specimen in the Academy of Natural Sciences of Philadelphia (ANSP 20219), said to be from the Kentucky River, which was identified by Rafinesque in 1831 as the species he had described in 1820 as Unio viridis. Debate in the second and third decades of the twentieth century (see also Ortmann and Walker, 1922 and Frierson, 1927) centered on whether the ANSP specimen, on the one hand, and Rafinesque's original description, on the other, was referable to Lasmigona compressa (Lea, 1829) or Lasmigona subviridis (Conrad, 1834). Ortmann and Walker (1922) identified the ANSP specimen as L. subviridis but decided that Rafinesque's description did not fit either L. subviridis or L. compressa and that Unio viridis was therefore unidentifiable. Johnson and Baker (1973) confirmed the identification of the specimen seen by Rafinesque in 1831, illustrated it, and restricted the type locality to Yellow Creek, near Cincinnati, which is the type locality of Symphynota [=Lasmigona] compressa Lea (1829).
Based on a conversation with Dr. David H. Stansbery, and further consideration, it seems certain that Rafinesque made a mistake in 1831 when he identified the (now ANSP) specimen as his Unio viridis. “Kentucky River,” the locality given for that specimen, must also have been added later; it is incorrect because L. subviridis does not occur there. (L. compressa does not occur there either.) The type locality restriction by Johnson and Baker is also inappropriate because it does not lie within the area of distribution of Unio viridis originally given by Rafinesque.
In order to stabilize the nomenclature of this species, selection of a neotype is necessary. None of Rafinesque's original material of Unio viridis is available (Johnson and Baker, 1973) so another specimen, from one of Rafinesque's localities (the Ohio River), is here designated. It is catalog number 8626a in the mollusk collection of the Smithsonian Institution. It is labelled “Cincinnati, Ohio.”
The specimen was previously in the Isaac Lea Collection and was originally collected by Mr. J. Clark at an unspecified date, but certainly in the nineteenth century. Its measurements are: length 58.45 mm height (excluding the ligament) 37.70 mm, width of both valves appressed 23.73 mm, distance from umbonal apex to anterior (B-A) 16.58, and hinge plate thickness (Hp) 3.85 mm.
- citação bibliográfica
- Clarke, Arthur Haddleton. 1980. "The tribe Alasmidontini (Unionidae, Anodontinae), Part I: Pegias, Alasmidonta and Arcidens." Smithsonian Contributions to Zoology. 1-101. https://doi.org/10.5479/si.00810282.326.1
