To title page of Tertiary Marine Pelecypods of California and Baja California
[Please cite as follows: Moore, E.J., 2002, Family Cardiidae, in Tertiary marine pelecypods of California and Baja California, Chapter F: http://www.cmug.com/~chintimp/Cardiidae.htm, 21 p., 2 pl.]
Family CARDIIDAE
Subfamily CARDIINAE
Genus ACANTHOCARDIA Gray, 1851
"Oblique-quadrate; cardinal teeth in left valve partially fused at base; ribs nodose to spinose." (Moore, 1969, p. N585)
Geographic range.--Europe, North and South America, eastern Pacific.
Geologic range.--Cretaceous to Holocene.
Subgenus ACANTHOCARDIA
Ribs spinose.
Geographic range.--Southern Europe, Mediteranean, eastern Pacific.
Geologic range.--Oligocene to Holocene.
Acanthocardia (Acanthocardia) reedi (Loel and Corey)
Plate 3, figure 1; Plate 3; Plate 3 caption
Cardium (Acanthocardia) reedi Loel and Corey, 1932, p. 213, pl. 37, fig. 3.
Original description.--"Several specimens of a small, sharply triangular ribbed (24) Cardium corresponding to the Acanthocardia were collected at various localities in the upper Vaqueros and Temblor transition zones of the La Panza Mountains, eastern San Luis Obispo County. Material is scant but the species is constant in small size and the distinctive triangular ribs."
Holotype.--UCMP 31772.
Type locality.--UC A-504. "Figured specimen collected from the Vaqueros-Temblor transition zone at Anderson Creek, La Panza Mountains, with a transitional faunule including Turritella inezana altacorona n. var., and T. ocoyana s.s." San Luis Obispo County, Calif. Vaqueros Formation, Oligocene and Miocene.
Occurrence in California.--Oligocene and Miocene: Temblor and Vaqueros Formations (Loel and Corey, 1932).
Genus ACANTHOCARDIA?
Subgenus ACANTHOCARDIA?
Acanthocardia? (Acanthocardia?) kirkensis Clark
Plate 3, figure 2; Plate 3; Plate 3 caption
Cardium kirkensis Clark, 1918, p. 140, pl. 12, fig. 5.
Original description.--"Shell small, inequilateral; beaks fairly prominent and rather strongly prosogyrous, anterior dorsal slope very slightly concave; posterior dorsal slope straight, about equal in length to the anterior slope; anterior end broadly and regularly rounded; posterior end broadly subtruncate, the lower angle of the truncation being obscure. Surface sculptured by from seventeen to twenty V-shaped, nodose, radial ribs, with interspaces averaging somewhat wider than the width of the ribs. Growth lines rather fine."
Holotype.--UCMP 11165.
Type locality.--UC 2033. Contra Costa County, Calif. Kirker Tuff, Oligocene.
Comparison.--"This species appears to be quite unique, differing from any of the known Recent or fossil cardiums of the West Coast." (Clark, 1918, p. 140)
Geographic range.--Middle California.
Geologic range.--Oligocene.
Occurrence in California.--Oligocene: Kirker Tuff (Clark, 1918).
Subgenus AGNOCARDIA Stewart, 1930
"Ribs numerous, flat-topped, with hollow, A-shaped spines." (Moore 1969, p. N585)
Geographic range.--North and South America.
Geologic range.--Eocene to Miocene.
Acanthocardia (Agnocardia) sorrentoensis (M.A. Hanna)
Plate 4, figure 5; Plate 4; Plate 4 caption
Cardium sorrentoensis M.A. Hanna, 1927, p. 285-286, pl. 41, figs. 10, 12, 14.
Trachycardium (Agnocardia) sorrentoense (M.A. Hanna). Vokes, 1939, p. 76.
Original description.--"Shell of moderate size, well inflated; margins rounded in general, not prominently truncated; beak only moderately prominent; surface of type badly weathered but crossed by coarse, equal sized ribs, about forty-six in number which are separated by interspaces about as wide as the ribs.
"Paratype 31002 shows the sculpturing very well. The ribs of this specimen are very slightly wider than the interspaces. Both the ribs and interspaces are squared. On the tops of the ribs are numerous chevron-shaped spines, with the apex of the chevron pointing toward the beak. Ribs which bear the chevron spines usually alternate with ribs which bear very much smaller node-like spines. This, however, is not always the case for in certain instances several ribs bearing the larger spines are adjacent. Usually the smaller nodes are more numerous to the rib than the larger spines, but both always for[m] a single row on a particular rib. With the material at hand no hinge could be exposed. Dimensions. Type: Length 36 mm., altitude 33 mm. Paratype 31001: Altitude 33 mm., length broken."
Holotype.--UCMP 31000.
Type locality.--UC 3795. San Diego County, Calif. Rose Canyon Shale, Eocene.
Comparison.--"Less oblique than A. (Acanthocardia); spines on ribs weak to obsolete, especially anteriorly." (Moore, 1969, p. N585).
Occurrence in California.--Paleocene: Cerros Shale Member, Lodo Formation (Vokes, 1939); Eocene: Rose Canyon Shale (M.A. Hanna, 1927)
Geographic range.--Southeast Asia, Africa, Europe, North and South America.
Geologic range.--Paleocene to Eocene.
Acanthocardia (Schedocardia) brewerii brewerii (Gabb)
Cardium brewerii Gabb, 1864, p. 173, pl. 24, fig. 155. Arnold, 1907b, pl. 39, fig. 5. McLaughlin and Waring, 1915, fig. 14. Waring, 1917, p. 92, pl. 14, fig. 9. Anderson and Hanna, 1925, p. 165-166, pl. 1, fig. 3. Clark, 1929, pl. 12, fig. 7.
Plagiocardium (Schedocardia) brewerii (Gabb). Stewart, 1930, p. 256-258, pl. 12, fig. 6. Turner, 1938, p. 52-53, pl. 9, figs. 6, 7. Vokes, 1939, p. 75, pl. 11, figs. 1-4. Stewart, 1946, pl. 11, fig. 20.
Plagiocardium brewerii (Gabb). Merriam and Turner, 1937, table 2.
Loxocardium (Schedocardia) brewerii (Gabb). Weaver, 1943, p. 153-154, pl. 35, figs. 15, 16, 18; pl. 38, figs. 1, 9; pl. 104, fig. 12.
Cardium (Trachycardium) brewerii brewerii (Gabb). Kleinpell and Weaver, 1963, p. 201-202, pl. 34, figs. 1,2.
Acanthocardia (Schedocardia) brewerii (Gabb). Givens, 1974, p. 48-49, pl. 1, fig. 17. Squires, 1984, p. 49, figs. 12a-b.
Acanthocardia brewerii (Gabb). Givens and Kennedy, 1979, table 4. Deméré, Sundberg, and Schram, 1979, pl.2, fig. 10.
Cardium modestum Conrad, 1855, p.11, pl. 2, fig. 15.
Original description.--"Shell moderate in size, subequilateral, subquadrate, a little wider than long; beaks central, strongly incurved; hinge-line nearly straight; anterior and basal margins forming a regular curve; posterior end abruptly truncated. Surface, in advance of a rounded, umbonal ridge, regularly convex; posterior slightly concave and sloping rapidly towards the posterior margin; ornamented by about 25 uniform subflattened ribs, with perfectly flat interspaces; the surface of these ribs is sometimes plain, sometimes faintly grooved longitudinally; the interspaces are creased by numerous minute squamose lines, which occasionally are visible on the ribs themselves."
Lectotype.--ANSP 4560 (Stewart, 1930, p. 257); of modestum USNM 1864.
Type locality.--East of north end of Grapevine Canyon, Kern County, Calif. Tejon Formation, Eocene. Of modestum, San Diego County, Calif. Presumably Eocene.
Supplementary description.--"Although rarely observed all the ribs of this species have large spines but they are either worn away before entombment, or, if preserved, are broken away with the matrix when the fossil is exposed." (Stewart, 1930, p. 257)
Occurrence in California.--Paleocene: Martinez (Kew, 1924) and Silverado (Woodring and Popenoe, 1945) Formations; Eocene: Avenal Sandstone (Stewart, 1946), Juncal (Givens, 1974; Squires, 1987), and Llajas (Squires, 1984) Formations, Matilija Sandstone (Page and others, 1951; Givens, 1974), and Tejon Formation (Arnold, 1907b; Stewart, 1930) ; Eocene and Oligocene: Gaviota Formation (Dibblee, 1950) and Sacate-Gaviota undifferentiated (Weaver and Kelinpell, 1963).
Acanthocardia (Schedocardia) brewerii robusta (Weaver and Kleinpell)
Cardium (Trachycardium) brewerii robusta Weaver and Kleinpell, 1963, p. 202, pl. 34, fig. 3.
Original description.--"Specimens not known to occur outside the Middle Gaviota are distinguished from the typical subspecies principally by their giant size; some of them measure more than four inches in height as well as in length. The surface is decorated with 22 radial ribs. The hinge line was not available."
Holotype.--CAS/SU 9290. (Missing and probably never deposited by Weaver.)
Type locality.--UC B-7010, Santa Barbara County, Calif. Middle Gaviota Member, Eocene and Oligocene.
Occurrence in California.--Eocene and Oligocene: Gaviota Formation (Weaver and Kleinpell,1963).
Acanthocardia (Schedocardia) brewerii hartleyensis (Clark and Woodford)
Plate 3, figure 11; Plate 3; Plate 3 caption
Cardium brewerii Gabb. Dickerson, 1916, p. 426, 427, 430, 444. Not Cardium brewerii Gabb, 1864.
Cardium brewerii Gabb, n. subsp. Clark, 1921, p. 158.
Cardium (Pingecardium) hartleyensis Clark and Woodford, 1927, p. 94, pl. 15, fig. 11.
Plagiocardium (Schedocardia) brewerii (Gabb) hartleyense (Clark and Woodford). Vokes, 1939, p.75-76, pl. 11, fig. 7.
Original description.--"Shell small, fairly heavy, about as high as long; beaks prominent and central, strongly incurved. Cardinal margins straight, about equal, ventral edge strongly and regularly arcuate; posterior end marked by a broad and abrupt truncation. Surface sculptured by about 22 fairly broad, prominent, flat-topped ribs with flat interspaces which are about equal to or slightly wider than the ribs, surface also covered by rather prominent, somewhat overlapping, incremental lines; those on the type are best preserved in the interspaces. An obscure, almost obsolete, umbonal ridge extending to the lower angulation of the truncated end, the surface being rather abruptly depressed posterior to this line, anterior to this the line of convexity is regular. Hinge not exposed. Dimensions: Height 9 mm., length, 9mm."
Holotype.--UCMP 31277.
Type locality.--UC 3609. Contra Costa County, Calif. Meganos Formation, Paleocene.
Comparison.--"Cardium hartleyensis belongs to the same subgenus as C. breweri Gabb, with which it might be confused. It differs from C. breweri in being smaller; the surface is not so strongly depressed posterior to the umbonal angle or ridge, and it has a smaller number of ribs, the typical C. breweri having about 25 ribs, and this species having only 21 or 22." (Clark and Woodford, 1927, p. 94)
Occurrence in California.--Paleocene: Cerros Shale Member, Lodo (Vokes, 1939) and Meganos (Clark and Woodford, 1927) Formations; Paleocene and Eocene: Santa Susana Formation (Vokes, 1939).
Subfamily TRACHYCARDIINAE
Genus TRACHYCARDIUM Mörch, 1853
"Shell robust, ovate, equilateral. Height greater than length. Sculpture of strong radial ribs, spinose on all or part of surface. Hinge plate strong, straight, short." (Coan, Scott, and Bernard, 2000, p. 361)
"The subgenus Trachycardium s.s., which has sculpture of imbricated scales over most of the surface but is nodose laterally, is not present in the northeastern Pacific." (Coan, Scott, and Bernard, 2000, p. 361)
Geographic range.--Tropical America and California.
Geologic range.--Eocene to Holocene.
Habitat.--Shallow seas.
Subgenus TRACHYCARDIUM
"Sculpture of imbricating scales over entire shell, reduced to beads anteriorly." (Moore, 1969, p. N586)
Geographic range.--North, Central, and South America.
Geologic range.--Oligocene to Holocene.
Trachycardium (Trachycardium) schencki (Wiedey)
Cardium schencki Wiedey, 1928, p. 143-144, pl. 17, figs. 3, 4.
Trachycardium schencki (Wiedey). Keen and Bentson, 1944, p. 35.
Cardium vaquerosensis Arnold. Arnold, 1910, p. 57, pl. 9, fig. 2. Not Cardium vaquerosensis Arnold, 1908.
Original description.--"Shell moderately large, subcircular in outline, slightly inequilateral, and gently to quite convex. The anterior dorsal margin is not long, but is straight and broadly rounded at the extremity. The basal margin is very broadly rounded to the posterior dorsal extremity, which is subtruncate. Posterior dorsal margin quite long, slightly concave or straight in outline, with a slight concavity from the umbo to the outer margin of the posterior dorsal area, running from under the beaks to the extremity of the shell. Umbones moderately large, prominent, elevated, with the beaks small, sharply pointed, strongly incurved, and perceptibly prosogyrous. The sculpture consists of thirty prominent ribs of flatly rounded cross section, with narrower interspaces. Incremental sculpture obscured. The breadth of the shell is slightly less than the length."
Holotype.--USNM 165598.
Type locality.--USGS 4631. Fresno County, Calif. Temblor Formation, Oligocene and Miocene.
Comparison.--"C. vaquerosensis Arnold can be readily distinguished from this new form [schencki] by the more cordate appearance of the shell, sharper and more prominently elevated umbones, which extend considerably above the hinge line, and in the smaller number of ribs of the Vaqueros species." (Loel and Corey, p. 144)
Occurrence in California.--Oligocene and Miocene: Temblor Formation (Loel and Corey, 1932; Eaton, 1941); Miocene: Santa Margarita (Dickinson, 1969) and Topanga (Keen and Bentson, 1944) Formations.
Trachycardium (Trachycardium) vaquerosensis (Arnold)
Cardium (Trachycardium) vaquerosensis Arnold, 1908, p. 378-379, pl. 34, fig. 3. Not Cardium vaqueroensis Arnold, 1910, p. 57, pl. 9, fig. 2. Loel and Corey, 1932, p. 213, pl. 37, fig. 1; fig. 38, fig. 3.
Original description.-"Shell attaining a length of over 100mm; nearly as high as long, subcircular in outline, very convex, quite thick; umbo prominent, protruding above hinge-line, subcentral, turned slightly toward anterior extremity; anterior extremity regularly rounded, posterior one somewhat flattened, forming two faint angles, the lower one of which is connected with the umbo by quite a pronounced angle in the surface of the shell, upper angle about two-fifths length of shell from umbo. Sculpture consists of about 34 tall, squarish ribs separated by deep channeled interspaces about equal in width to the ribs; the ribs become less and less conspicuous toward the ends of the shell; incremental sculpture well developed, and making a convex bow upward toward the umbo on top of each rib. Hinge and interior probably similar to C. quadrigenarium."
Holotype.--USNM 165457.
Type locality.--"One mile [1.6 km] above confluence of Mindego Cr. and Alpine Cr.", [NE 1/4 sec. 24, T. 7 S., R. 4 W., Santa Cruz Quad.], San Mateo County, Calif." Vaqueros Formation, Oligocene and Miocene.
Supplementary description.--"This large, few-ribbed (34) Cardium, having wide distribution in the Vaqueros formation, is variable in outline. In some regions this form does not attain large size and may be mistaken for a new species." (Loel and Corey, 1932, p. 214).
Comparison.--"This species [vaquerosensis] is doubtless the precursor of C. quadrigenarium Conrad, from the Pleistocene and Recent fauna, but differs from the latter in being bilaterally more symmetrical on account of being less produced in the ventro-posterior region, having only about three-fourths as many ribs (34 instead of about 45), having narrower, steeper sided ribs and a more prominent angle extending from umbo to posterior extremity. It differs from C. quadrigenarium Conrad, var. fernandoensis Arnold, from the lower Pliocene, by being much larger, more convex, having more prominent umbones, and having fewer, wider, deeper, steeper-sided interspaces. Named for the Vaqueros formation, of which it is believed to be characteristic." (Loel and Corey, 1932, p. 213)
Geographic range.--Middle to southern California.
Geologic range.--Oligocene and Miocene.
Occurrence in California.--Oligocene and Miocene: Buttonbed and Carneros Sandstone Members, Temblor (Addicott, 1973) and Vaqueros (Arnold, 1908) Formations; Miocene: Tierra Redonda (Durham, 1965) and Topanga (Takeo Susuki, written commun., 1978) Formations.
Trachycardium (Trachycardium) arcumbona (Wiedey)
Plate 4, figure 8; Plate 4; Plate 4 caption
Cardium arcumbona Wiedey, 1928, p. 142-143, pl. 17, fig. 5.
Trachycardium arcumbona (Wiedey). Keen and Bentson, 1944, p. 33.
Original description.--"Shell of moderate size, subquadrate in outline, slightly inequilateral, and only gently convex. Anterior dorsal margin is concavely rounded under the beak and convexly rounded toward the extremity, with the anterior dorsal area separated from the main body of the shell by a distinct shoulder from the beak to the extremity. This area is nearly straight and is well flattened. Anterior extremity quite sharply rounded, with the base broadly convex; posterior dorsal extremity apparently moderately rounded; posterior dorsal margin not long and sloping quite straight from the beak. Umbo not large, but prominent, elevated, incurved, with a tendency to be angular. Beak small, slightly anterior, sharp, gently elevated, and distinctly prosogyrous. The sculpture consists of about twenty broadly rounded ribs, wider than the interspaces. Length, about 35 mm.; breadth, 32 mm.; thickness of a single valve, about 14 mm."
Holotype.--SDNM 31.
Type locality.--SU 432. San Luis Obispo County, Calif. Temblor Formation, Oligocene and Miocene.
Comparison.--"This new species [arcumbona] differs from other known forms of the West Coast fossil Cardiums in the possession of the distinctive flattening of the anterior dorsal area, anterior to the prominent shoulder in that part of the valve." (Wiedey, 1928, p. 143)
Occurrence in California.--Oligocene and Miocene: Temblor Formation (Wiedey, 1928; Eaton, 1941).
Trachycardium (Trachycardium) woodringi (Loel and Corey)
Plate 3, figure 16; Plate 3; Plate 3 caption
Cardium (Trachycardium) woodringi Loel and Corey, 1932, p. 214, pl. 37, fig. 2.
Original description.--"Shell medium size, moderately convex; valves equilalteral, equivalve, suborbicular, with but moderately inflate[d], low umbones; posterior dorsal margin but gently arched, meeting posterior margin in obtuse angle; margins otherwise evenly regularly rounded; surface sculptured by about 22 narrow, flat, squarish ribs. Height, 30 mm.; length, 31 mm.; thickness (left valve), 13 mm."
Holotype.--UCMP 31774.
Type locality.--UC A-495. San Luis Obispo County, Calif. Vaqueros Formation, Oligocene and Miocene.
Comparison.--"It [woodringi] is distinct from C. (T.) vaquerosensis Arnold, to which species it is nearest related, in its constant ten or more fewer ribs." (Loel and Corey, 1932, p. 214)
Occurrence in California.--Oligocene and Miocene: Vaqueros (Arnold, 1908; Loel and Corey, 1932) Formation.
Subgenus DALLOCARDIA Stewart, 1930
"Shell large, with strong radial ribs, spinose, sometimes firilled posteriorly. Spines on anterior slope on anterior sides of ribs, those on central and posterior slopes on posterior sides of ribs." (Coan, Scott, and Bernard, 2000, p. 361)
Geographic range.--North and South America.
Geologic range.--Oligocene to Holocene.
Trachycardium (Dallocardia) quadragenarium quadragenarium (Conrad)
C[ardium]. quadragenarium Conrad, 1837, p. 230, pl. 17, fig. 5.
Laevicardium (Trachycardium) quadragenarium (Conrad). Grant and Gale, 1931, p. 306, pl. 19, fig. 15.
Trachycardium quadragenarium Conrad. Fitch, 1953, p. 55, fig. 21. Abbott, 1974, p. 483, fig. 5551. Morris and others, 1980, p. 370, fig. 15.27.
Cardium (Dallocardia) quadragenarium Conrad. Hertlein and Grant, 1972, p. 259-260, pl. 46, figs. 18, 20, 23.
Trachycardium (Dallocardia) quadragenarium (Conrad). Woodring, 1938, p. 53, pl. 9, fig. 1.
Trachycardium (Dallocardia) quadragenarium (Conrad, 1837). (Coan, Scott, and Bernard, 2000, p. 362, pl. 75)
Original description.--"Shell cordate, subequilateral, ventricose, thick; ribs forty to forty-two, prominent, subangular, flattened at the sides with a series of small tubercles, which, on the anterior side, are largest, and placed in the middle of the ribs, but elsewhere on the posterior angular margin of the ribs; umbo broad, prominent; beaks not oblique; tubercles elevated on the posterior slope; colour pale yellow, with fulvous spots and zones; posterior margin direct, deeply serrate. Height three inches."
Holotype.--Location unknown.
Type locality.--"Inhabits near Sta. Barbara; rare." Holocene.
Supplementary description.--"Shell solid, inflated, ovate to rhomboidal. Sculpture of more than 40 strong, closely spaced, radial ribs, with small thorn-like spines, stronger on the lateral and ventral parts of the shell.***Shell margins deeply crenulate. Length to 150 mm." (Coan, Scott, and Bernard, 2000, p. 362)
Occurrence in California.--Miocene: Cierbo (Weaver, 1949) and Neroly Sandstones, San Pablo Group (Hall, 1960), Pancho Rico (Durham and Addicott, 1966), Santa Margarita, and Temblor (Grant and Gale, 1931) Formations; Miocene and Pliocene: Etchegoin (Clark, 1915) and Towsley (Kern, 1973) Formations; Pliocene: Niguel (J.G. Vedder, written commun.,1978) and San Diego (Hertlein and Grant, 1972) Formations; Pliocene and Pleistocene: Fernando (Soper and Grant, 1932; Kennedy, 1975), Merced (Martin, 1916), Pico (Waterfall, 1929; Winterer and Durham, 1962), San Pedro (Oldroyd, 1924), and Saugus (Waterfall, 1929; Givens, 1991) Formations; Pleistocene: unnamed strata at Potrero Canyon, (Valentine, 1956), Newport Bay (Kanakoff and Emerson, 1959), Torrey Pines Park (Valentine, 1960), California and at Bahía San Quintin, Baja California Norte (Jordan, 1926) and Baja California Sur (Emerson, 1980).
Habitat.--Living middle California to Baja California Sur. From intertidal zone to 135 m; in sandy mud with the edges of the valves projecting above the surface. In sloughs and sheltered waters of the open coast. (Hertlein and Grant, 1972, p. 259) "In the intertidal zone to 50 m, in sand or mud of bays and offshore." (Coan, Scott, and Bernard, 2000, p. 362)
Trachycardium (Dallocardia) quadragenarium fernandoensis (Arnold)
Plate 3, figures 17, 19; Plate 3; Plate 3 caption
Cardium quadragenarium Conrad, var. fernandoensis Arnold, 1907, p. 535, pl. 48, figs. 2, 2a.
Laevicardium (Trachycardium) quadragenarium var. fernandoense (Arnold). Grant and Gale, 1931, p. 307.
Trachycardium (Dallocardia) fernandoensis (Arnold). Keen and Bentson, 1944, p. 34.
Original description.--"Shell smaller than the typical form, oval, ventricose; umbones central, prominent, turned only slightly anteriorly; surface sculptured with about thirty-six prominent, subangular radiating ridges roughened over the anterior and posterior portions of the shell by prominent pointed tubercles on the posterior angle; those ridges near the posterior margin are less prominent, but are nodose for nearly their whole length."
Holotype.--USNM 164947.
Type locality.--"Elsmere Canyon, near Pacific Coast Oil Company's well, 2 1/2 miles [4.0 km] southeast of Newhall, Los Angeles County, California." Pico Formation, Pliocene and Pleistocene.
Comparison.--"This variety [fernandoensis] is more oblique, has narrower umbones, is relatively less in diameter, and has fewer and less prominently spinose ribs than the typical [quadrigenarium] form." (Arnold, 1907, p. 535)
Comments.--Bernard (1983, p. 38) synonymized fernandoensis with quadragenarium.
Occurrence in California.--Pliocene and Pleistocene: Fernando Formation (Arnold, 1907).
Trachycardium (Dallocardia) sagaseri Adegoke
Plate 3, figure 15; Plate 3; Plate 3 caption
Trachycardium sagaseri Adegoke, 1969, p. 116-117, pl. 3, figs. 4, 6, 8.
Original description.--"Shell medium sized to large, elongate, slightly oblique and inequilateral, similar to T. fernandoense (Arnold); outline elongate oval; beaks fairly prominent, centrally located, incurved and very slightly prosogyrous; anterior dorsal margin short, about one-fifth height of shell, gently concave, with rather inconspicuous lunule; posterior dorsal margin straight, about half height of shell; ventral margin evenly but sharply rounded giving a lobelike appearance; surface ornamented by about 28 prominently elevated ribs, interspaces slightly narrower than ribs; rib profile subacutely rounded."
Holotype.--UCMP 36686.
Type locality.--UC D-1134. Fresno County, Calif. Etchegoin Formation, Miocene and Pliocene.
Comparison.--"T. sagaseri n. sp. differs from T. quadragenarium (Conrad) and T. fernandoense (Arnold) by its 28 ribs in contrast to 40 to 42 and 36 ribs in Conrad's and Arnold's species respectively." (Adegoke, 1969, p. 117)
Occurrence in California.--Miocene and Pliocene: Etchegoin Formation (Adegoke, 1969).
Trachycardium (Dallocardia) senticosum (Sowerby)
Cardium senticosum Sowerby, 1833, p. 84.
Cardium (Dallocardia) senticosum Sowerby. Hertlein and Strong, 1947, p. 147-148. Olsson, 1961, p. 246-247, pl. 37, fig. 3.
Trachycardium (Dallocardia) senticosum (Sowerby, 1833). Keen, 1971, p. 153, fig. 362.
Original description.--"Card. testii suborbiculari, compressiusculii, albidi, purpurascenti-fusco variegatd; costis radiautibus 39-40, tredecim anticis anticè graniferis; demum 2-3 utrinque graniferis; reliquis posticè angulatis, graniferis, granis obliquis, posteriorbus majoribus; interstitis omnibus angustis, transervsim striatis; latere postico ringente, dentibus marginalibus validis purpurascentibus: long. 1.5, lat. 1.1, alt. 1.5 poll."
Holotype.--BM(NH)?
Type locality.--"ad Sanctam Elenam, Americae Meridionalis."
Supplementary description.--"Shell subcircular to subovate, with moderately convex valves. The ribs are small and usually number about 35. Imbrication of the ribs is formed by relatively small scales, sometimes partly spinous on the posterior slope and confined mostly to the marginal areas, the middle ribs smooth." (Olsson, 1961, p. 247)
Occurrence in California.--Miocene: Topanga Formation (Schoellhamer and others, 1981)
Habitat.--Found in sandy mud at from 6 to 12 fathoms [11 to 22 m] (Sowerby, 1833, p. 84); 5 to 25 m (Bernard, 1983, p. 38). Living Pacific side of Baja California Sur and the whole Gulf of California to Peru.
Genus PAPYRIDEA Swainson, 1840
"Shell longer than high, gaping at both ends, ribs spinose; hinge short; posterior margin notched." (Moore, 1969, p. N588)
Geographic range.--West Indies; southern California, and Baja California Sur.
Geologic range.--Miocene to Holocene.
Papyridea crockeri (Strong and Hertlein)
Cardium (Papyridea) crockeri Strong and Hertlein, 1937, p. 161-162, pl. 34, figs. 1, 2, 7, 10.
Papyridea crockeri (Strong and Hertlein). Olsson, 1971, p. 249, pl. 38, figs. 5-5b.
Original description.--"Shell ovate, a little longer than high, beaks nearly central; posterior gape distinct; anterior dorsal margin with a narrow depressed area; sculptured with forty-eight low, flattened, radiating ribs with much narrower interspaces, strongest at the posterior end, becoming narrower toward the anterior end; of these ribs twelve on the posterior end and eighteen on the anterior end are imbricated by small, pointed folds, more or less worn off toward the beaks, central ribs smooth, exterior yellowish white with short patches of red arranged in irregular concentric zones on the ribs; interior white, stained with reddish toward the beaks on the anterior side; margins creulated; ligament external, strong, short; hinge with one cardinal and two laterals in each valve. The type measures: length, 46.8 mm., height, 42 mm., thickness of the two valves, 29 mm."
Holotype.--CAS 6969.
Type locality.-CAS 27,588. Dredged in Lat. 24°14' to 24°18'N., Long 118°28' to 111°29' W., about 13 miles [11 km] southeast of Cabo Tosco, Isla Santa Margarita, Baja California Sur. Holocene.
Comparison.--"This species [crockeri] differs from Cardium (Papyridea) aspersum Sowerby, in possessing a more convex shell, which has a more rounded outline***The anterior plate on the hinge, which bears a groove and lateral tooth, is longer than the corresponding plate in Cardium aspersum." (Strong and Hertlein, 1937, p. 162)
Occurrence in California.--Miocene and Pliocene: Imperial Formation (Powell, 1988)
Habitat.--Living Baja California Sur.
Subfamily FRAGINAE
Genus AMERICARDIA Stewart, 1930
"Shell quadrate, with high, wide umbones. Ribs flat-topped; interspaces with commarginal striations. Intritacalx with numerous arched commarginal threads on ribs, some stronger, scale-like. Cardinal teeth strongly unequal; anterior laterals a little closer to cardinals than are posterior laterals." (Coan, Scott, and Bernard, 2000, p. 359)
Comments.--Woodring (1982, p. 642) stated that although Americardia is usually assigned subgeneric rank under Trigoniocardia, treatment of both as genera is justified.
Geographic range--Living: Central America; fossil: Baja California Sur.
Geologic range.--Miocene to Holocene.
Americardia guanacastense (Hertlein and Strong)
Cardium (Americardia) guanacastense Hertlein and Strong, 1947, p. 140.
Original description.--"Shell somewhat cordate, the beaks somewhat attenuated, rounded anteriorly, truncated posteriorly, umbos angulated posteriorly and sloping abruptly downward, the median portion of the posterior area concave; sculptured with about 30 narrow, flat-topped ribs of which about 20 occur anterior to the posterior umbonal angulation and about 10 posterior to it, ribs and interspaces crossed by fine concentric imbrications; hinge with 2 cardinals, the anterior the larger, and 2 laterals which are double in the left valve; exterior yellowish-white and pinkish and with somewhat irregularly concentric blotches of brown, the interior white. The type measures: height (beak to base), 25 mm.; length, approximately, 22 mm. Another specimen, a right valve, measures: height, 46 mm.: length, 36 mm."
Holotype.--CAS.
Type locality.--Culebra Bay, Province of Guanacaste, Costa Rica. Holocene.
Comparison.--"The shell of this species [guanacastense] is in general shape similar to that of Cardium biangulatum but it is proportionately higher and narrower, has about 30 radial ribs which are narrower***" (Hertlein and Strong, 1946, p. )
Occurrence in California.--Miocene and Pliocene: Imperial Formation (Powell, 1988).
Habitat.--10 to 150 m (Bernard, 1983). Living Gulfo de California to Peru.
Americardia biangulata (Broderip and Sowerby)
Plate 4, figures 1-4; Plate 4; Plate 4 caption
Cardium biangulatum Broderip and Sowerby, 1829, p. 367. Jordan, 1936, p. 133.
Fragum biangulatum (Broderip and Sowerby). Grant and Gale, 1931, p. 312.
Americardia biangulata (Broderip and Sowerby). Durham,1950, p. 79, pl. 19, figs. 7,13.
Americardia biangulata (Broderip and Sowerby, 1829) Coan, Scott, and Bernard, 2000, p. 359, pl. 75.
Trigoniocardia (Trigoniocardia) biangulata (Broderip and Sowerby). Olsson, 1961, p. 251, pl. 37, figs. 6 6a.
Trigoniocardia (Americardia) biangulata (Broderip and Sowerby, 1829). Keen, 1971, p. 157, fig. 570.
Original description.--"C. testâ turgidâ, obliquê subcordatâ, antice' rotundatâ, potice' biangulatâ; costis radiantibus longitudinaliter striatis, anticis subcrenatis, posticis rugulosis; interstitiis punctatis; long. 9/10, lat. 6/10, alt. 8/10, poll."
Holotype.--BM(NH)?
Type locality.--
Supplementary description.--"Shell of medium size, with prominent, convex umbones and well rounded anterior side. Ribs low, rounded, close-set, the narrow interspaces closely and regularly cross-threaded. (Olsson, 1961, p. 251)
"Shell thick; posterior end truncate. Sculpture of about 26 broad, flat, imbricate radial ribs; interspaces with fine commarginal lirae." (Coan, Scott, and Bernard, 2000, p. 359)
Occurrence in Baja California.--Pliocene: Comandú and Marquer Formations (Durham, 1950); Pleistocene: Palos Verdes Sand (Mount, 1975), unnamed sediments in Baja California Norte (Jordan, 1926; Kanakoff and Emerson, 1959) and Sur (Hertlein, 1934; Durham, 1950).
Habitat.--Intertidal to 155 m (Keen, 1971, p. 157; Bernard, 1983, p. 38). Fairly common on sublittoral gravel near rock (McLean, 1978). Living Santa Cruz Island, California, to Ecuador. In the intertidal zone to 100 m (Coan, Scott, and Bernard, 2000, p. 359)
Genus NEMOCARDIUM Meek, 1876
"Sculpture of radial ribs and striae, usually stronger on posterior slope; central slope sometimes nearly smooth; ribs on posterior slope often spinose; inner ventral margin crenulate." (Coan, Scott, and Bernard, 2000, p. 360)
Subgenus NEMOCARDIUM
"Quadrate, ribbing of posterior slope much coarser than on remainder of shell, marginal crenulations changing abruptly in size at boundary between posterior and central slopes." (Keen, 1954)
Geographic range.--Almost cosmopolitan but not found living in the northeastern Pacific.
Geologic range.--Cretaceous to Holocene.
Nemocardium (Nemocardium) linteum (Conrad)
Plate 3, figure 5; Plate 3; Plate 3 caption
Cardium linteum Conrad, 1855, p. 3, 9. 1857, pl. 2, fig. 1. Anderson and Hanna, 1925, p. 166-167, pl. 3, fig. 3.
Cardium (Nemocardium) linteum Conrad. Kleinpell and Weaver, 1963, p. 202, pl. 34, fig. 4.
Nemocardium linteum (Conrad). Stewart, 1930, p. 275-277, pl. 8, fig. 6. Turner, 1938, p. 52, pl. 10, fig. 10. Vokes, 1939, p. 76-77, pl. 11, figs. 6, 9. Weaver, 1943, p. 159-160, pl. 38, fig. 3. Stewart, 1946, pl. 11, fig. 19. Moore, 1968, pl. 13d. Zinsmeister, 1974, p. 97-98, pl. 9, figs. 7-9. Zinsmeister, 1983, pl. 2, fig. 7. Givens and Kennedy, 1979, table 4. Squires, 1984, p. 49-50, fig. 12c. Squires, 1987, p. 65, 67, fig. 113. Squires, Cox, and Powell,1988, p. 185, fig. 8. Squires, 1988, p. 19. Squires and Demetrion, 1992, p. 42, fig. 121.
Nemocardium (Nemocardium) linteum (Conrad). Givens, 1974, p. 49.
Cardium cooperi Gabb, 1864, p. 172, pl. 24, figs. 154, 154a. Hanna, 1927, p. 285, pl. 41, figs. 6, 7.
Cardium dalli Dickerson, 1913, p. 289, pl. 14, figs. 4a-c. Not Cardium dalli Heilprin, 1887.
Cardium marysvillensis Dickerson, 1916, p. 482, [new name for Cardium dalli Dickerson, 1913, preoccupied].
Cardium (Protocardium) marysvillensis Dickerson. Clark and Woodford, 1927, p. 94, pl. 15, fig. 12.
Original description.--"Cordate, ventricose subequilateral, with closely arranged radiating lines, umbonal slope subcarinated; posterior submargin with closely arranged smooth striae, fine, but much larger than those of the disk." (linteum)
Holotype.--USNM 1834; ANSP 4468 (cooperii); UCMP 11756 (dalli).
Type locality.--Grapevine Canyon, Kern County, Calif. Domengine Formation (Squires, 1987, p. 65), Eocene. Of cooperi, Contra Costa County, Calif. Martinez Formation, Paleocene. Of dalli, Marysville Buttes, Sutter County, Calif. Marysville Formation, Eocene
Occurrence in California.--Paleocene: Martinez (Gabb, 1864) and Goler (Squires and others, 1988) Formations; Eocene: Bateque (Squires and Demetrion, 1992), Domengine, Juncal (Givens, 1974; Squires, 1987), Llajas (Squires, 1984), Matilja (Givens, 1974) , and Tejon (Arnold, 1906).Formations, and Rose Canyon Shale (Arnold, 1907b; Moore, 1968).
Nemocardium (Nemocardium) lorenzanum (Arnold)
Plate 3, figures 6, 18; Plate 3; Plate 3 caption
Cardium cooperi lorenzanum Arnold, 1908, p. 366, pl. 33, fig. 6.
Cardium cooperi Gabb lorenzanum Arnold. Arnold, 1909, p. 4, fig. 17. Weaver, 1912, p. 18.
Cardium lorenzanum Arnold. Clark, 1915, p. 14, 18. Clark, 1918, p. 141. Tegland, 1933, p. 116-117, pl. 7, figs. 16, 17.
Original description.-- "Shell attaining a length of only about 14mm; somewhat longer than high; end view of both valves together has a cordate appearance; outline of a single valve subcircular; shell very convex, thin; umbo small, prominent, turned slightly forward, projecting beyond dorsal margin; dorsal margin straight for short distance under umbo, bends off slightly more angularly posteriorly than it does anteriorly; extremities broad and regularly rounded, as is also the base; surface sculptured by fine incremental lines and by numerous fine radiating lines, those over the posterior end being larger and more prominent than those on the remainder of the shell, and distinctly separated from the latter by a faint angle in the surface of the shell extending from umbo to posterior ventral margin. Margin minutely crenulate. Lunule faint or lacking. Dimensions: Length 14mm; altitude 12.5mm; diameter of single valve, 4.5mm."
Holotype.--USNM 165444.
Type locality.--USGS 4063. Porter, Chehalis County, Wash. Lincoln Creek Formation, Eocene to Miocene.
Supplementary description.--"***on the major portion of the shell the ribs are broad, flattened, and separated merely by an incised line; on the posterior end they are narrow, high, separated by interspaces equal to width of ribs." (Tegland, 1933, p. 117)
Occurrence in California.--Eocene and Oligocene: San Lorenzo Formation (Arnold, 1908); Oligocene: Kirker Tuff (Clark, 1918); Miocene(?): San Ramon Formation (Clark, 1918).
Subgenus KEENAEA Habe, 1951
Resembling Nemocardium (Pratulum) but with secondary concentric sculpture on posterior slope. (Moore, 1969, p. N589)
"Shell thin, with discrepant sculpture; ribs on anterior and central slopes low, rounded and crowded; ribs on posterior slope higher, with wider interspaces and commarginal lirae." (Coan, Scott, and Bernard, 2000, p. 360)
Geographic range.--Japan and western North America.
Geologic range.--Oligocene to Holocene.
Nemocardium (Keenaea) centifilosum (Carpenter)
Plate 3 , figures 3, 4; Plate 3; Plate 3 caption
Cardium (?modestum, var.) centifilosum Carpenter, 1864, p. 611, 642. 1866, p. 209.
Cardium centifilosum Carpenter. Dall, 1874, p. 297.
Protocardia centifilosa (Carpenter). Arnold, 1903, p. 142.
Cardium (Protocardia) centifilosum Carpenter. Packard, 1918, p. 267, pl. 20, figs. 2a-2d.
Laevicardium (Nemocardium) centifilosum (Carpenter). Grant and Gale, 1931, p. 311, pl. 19, figs. 9, 10.
Pratulum centifilosum (Palmer). Woodring and others, 1946, p. 85, pl. 33, figs. 10, 11.
Nemocardium (Keenaea) centifilosum (Carpenter). Palmer, 1958, p. 91-92, pl. 10, figs. 7-11. Hertlein and Grant, 1972, p. 263-264, pl. 46, figs. 4, 5, 10, 15.
Original description.--"Probably = modestum, Ad. & Rve.; but rounder, ribs sharper and more distant."
Holotype.--USNM 15262.
Type locality.--Catalina Island, Calif., Holocene (Palmer, 1958, p. 92).
Supplementary description.--"Shell ovate, thin and inflated. Sculpture of posterior slope cancellate, with about 20 radial ribs, separated from central slope by a raised radial rib. Central and anterior slopes with 40 or more flat, fine, radial riblets. Umbones prominent, subcentral. Inner margin finely crenulate. Length to 25 mm." (Coan, Scott, and Bernard, 2000, p. 361)
Comparison.--"It [centifilosum] differs from L. substriatum in its stronger ribbing, in its posterior cancellate sculpture, and in its orbicular shape. L. substriatum is slightly elongated at the posterior ventral portion, and the radial sculpture is very low and inconspicuous." (Grant and Gale, 1932, p. 311)
Occurrence in California.--Miocene: Modelo Formation (Wright, 1948); Miocene and Pliocene: Capistrano Formation (Kern and Wicander, 1974); Pliocene: San Diego Formation (Hertlein and Grant, 1972); Pliocene and Pleistocene: Fernando Formation (Eldridge and Arnold, 1907; Soper and Grant, 1932); Pleistocene: Lomita Marl Member and Timms Point Silt Member, San Pedro Formation (Woodring and others, 1946).
Habitat.--30 to 150 m. Living Alaska to Baja California Sur. (Coan, Scott, and Bernared, 2000, p. 361)
Subgenus LOPHOCARDIUM Fischer, 1887
"Fragile, sculpture of faint sinuous radial and concentric threads; periostracum forming laminar keel at junction of posterior and central slopes; cardinal teeth well developed, lateral teeth obsolescent." (Moore, 1969, p. N589)
Geographic range.--Southern California, Central America, and South America.
Geologic range.--Eocene(?); Miocene to Holocene.
Nemocardium (Lophocardium) gurabicum (Maury)
Protocardia gurabica Maury, 1917, p. 213, pl. 36, fig. 10.
Protocardia (Lophocardium) gurabica Maury. Olsson, 1922, p. 229, pl. 27, figs. 7-9.
Lophocardium gurabicum (Maury). Woodring, 1982, p. 645-646, pl. 114, figs. 1, 2, 6.
Original description.--"Shell resembling the Vicksburgian Oligocene P. diversa Conrad, but differing in the following respects:- (1) the posterior sculpture in diversa consists of about twenty to twenty-five very sharply defined, highly raised, radiating threads with wider interspaces; in our fossil there are about forty-three crowded, flattened, slightly wavy threads with interspaces much narrower, reduced to mere lines; (2) in diversa the ending of the posterior sculpture is defined simply by a slightly heavier radiating thread in our shell its termination is defined by a fine but sharp carination extending from the umbonal region to the base, the posterior slope of this carination forming a smooth band marked only at frequent intervals by fine, oblique raised growth-striae; (3) the posterior region is very slightly undulate in diversa but markedly so in our fossil, there being two sulci with a fold between; (4) the sculpture over the central part of our shell is much finer and more delicate, consisting of fine radial and concentric lines; and anteriorly the concentric lines are sharper than in diversa. Length 24, approximate altitude 21, diameter 18 mm."
Holotype.--Paleo. Res. Institute.
Type locality.--Río Gurabo at Los Quemados, Dominican Republic. Gurabo Formation, Miocene.
Supplementary description.--"Large, broadly ovate, height less than length, inequilateral, posterior end more extended than anterior, and valves gaping. Umbo high and strongly inflated. Lunule narrow, inflated. Sculpture finely reticulate, ribs slightly stronger and slightly more widely spaced than concentric threads. Sculpture of posterior slope like that of remainder of valve and slope not set off by thin radial lamella. Left anterior cardinal tooth strong; posterior cardinal tooth minute. Left posterior lateral tooth suppressed as compared with anterior lateral tooth. Right hinge unknown." (Woodring, 1982, p. 646)
Comparison.--"L. gurabicum is distinguished from the two surviving species in the eastern Pacific Ocean [annettae and cumingii] by the absence of a thin radial lamella setting off the posterior slope and by the presence, at least on the left valve, of a weak posterior lateral tooth and a strong anterior lateral tooth. The hinge of no other fossil specimen is known." (Woodring, 1982, p. 646)
Occurrence in California.--Miocene and Pliocene: Imperial Formation (Powell, 1988)
Subfamily LAEVICARDIINAE
Genus LAEVICARDIUM Swainson, 1840
"Radial ribs weak, obscure on posterior slope, smooth or rarely nodose. (Coan, Scott, and Bernard, 2000, p. 259)
Geographic range.--Europe, Atlantic, Pacific.
Geologic range.--Eocene to Holocene.
Subgenus LAEVICARDIUM
Smooth, nongaping; cardinals unequal.
Geographic range.--Europe, western Atlantic, eastern and western Pacific.
Geologic range.--Eocene to Holocene.
Laevicardium (Laevicardium) elenense (Sowerby)
Cardium elenense Sowerby, 1840, p. 6, no. 73, fig. 58; 1841, p. 109.
Cardium (Laevicardium) elenense Sowerby. Hertlein and Strong, 1947, p. 145-146.
Laevicardium elenense (Sowerby). Durham, 1950, p. 80, pl. 19, figs. 2, 12. Keen, 1971, p. 160, fig. 379.
Laevicardium (Laevicardium) elenense (Sowerby). Olsson, 1961, p. 256, pl. 38, figs. 2, 2a.
Original description.--"Card. testâ tenui, laevi, ovali, posticè subacuminatâ pallide fulvâ, fusco et purpureo minutè maculatâ, intùs fuscâ rubro fasciatâ; umbonibus inconspicuis, purpureo maculatis."
Holotype.--BM(NH)?
Type locality.--"ad Sanctam Elenam" [Santa Elena, Equador].
Supplementary description.--"The shell is generally small (less than 20 mm., high), obliquely subovate, the posterior-dorsal slope narrowly flattened, its margin straight. Surface smooth, polished, but weakly rayed.***Strength of the radial ribbing is variable." (Olsson, 1961, p. 256)
Geologic range.--Miocene to Holocene.
Occurrence in the Californias.--Miocene and Pliocene: Imperial Formation (Powell, 1988); Pliocene: Comandú and Marquer Formations (Durham, 1950); Pleistocene: Unnamed strata, Baja California Sur (Hertlein, 1934; Durham, 1950).
Habitat.--Rare intertidally, mainly offshore in depths to 90 m. (Keen, 1971, p. 160) Living Golfo de California to northern Peru.
Subfamily CLINOCARDIINAE
Genus CLINOCARDIUM Keen, 1936
"Shell oblique to elliptical, inflated. Sculpture of radial ribs and commarginal lirae. Periostracum thin, adherent, occasionally hirsute on ribs. Umbones prominent, prosogyrate. Hinge plate wide." (Coan, Scott, and Bernard, 2000, p. 351).
Geographic range.--North Pacific and northwest Atlantic.
Geologic range.--Miocene to Holocene.
Subgenus CLINOCARDIUM
"Ribs tubercular, weaker on posterior slope; periostracum smooth." (Coan, Scott, and Bernard, 2000, p. 351)
Clinocardium (Clinocardium) praeblandum Keen
Plate 3, figure 14; Plate 3; Plate 3 caption
Cardium quadrigenarium Conrad. Clark, 1915, pl. 47, fig. 3. Not C. quadragenarium (Conrad).
Cardium praeblandum Keen, 1954, p. 15-16, pl. l, figs. 1, 6; text figs. 5, 6.
Original description.--"Trigonal, subequilateral, ventricose; dorsal margins joining ventral in a broad curve; ventral margin arcuate; umbones low, beaks slightly inturned; sculpture of 35 to 40 smooth radial ribs (40 on holotype), faintly defined on posterior slope; ribs in cross section arched, interspaces linear."
Holotype.--UCMP 14836.
Type locality.-- "West end of Las Trampas Ridge near Walnut Creek, Concord Quad., Contra Costa Co., California." Briones Sandstone, San Pablo Group, Miocene.
Comparison.--"Because of the numerous ribs, this species [C. praeblandum] and C. pristinum Keen***have been confused by authors with the Recent Trachycardium (Dallocardia) quadragenarius, a form that has well-developed spinose ribs on the posterior slope and a relatively short, straight hinge. In outline, number of ribs, and degree of ventricosity this new species agrees well with the Recent C. blandum (Gould) but differs in being considerably larger, an average C. blandum having a height of about 25 mm." (Keen, 1954, p. 16)
Occurrence in California.--Miocene: Briones Sandstone, San Pablo Group (Keen, 1954).
Clinocardium (Clinocardium) pristinum Keen
Clinocardium pristinum Keen, 1954, p. 16-17, pl. 1, figs. 9, 15; text figs. 7, 8.
Original description.--"Trigonal, inequilateral, ventricose; posterior dorsal margin straight, sloping downward at an angle of 140°; ventral and anterior margins broadly rounded; beaks at the anterior third, moderately inturned below the prominent, strongly curved umbones; ligamental area long, escutcheon faintly outlined; lunule absent; sculpture of 42-48 radial ribs (46 on holotype); ribs on the posterior slope tending to be obsolete; in cross section ribs flattened at the top, sloping at an angle of about 45° to the narrow interspaces; hinge as in C. nuttalli Conrad, with 2a and 3b strong, 2b and 3a weak."
Holotype.--UCMP 14838.
Type locality.--"Southwest part of Shell Ridge, near Walnut Creek, Concord Quad., Contra Costa Co., California." Neroly Sandstone, San Pablo Group, Miocene.
Comparison.--"This species [C. pristinum] resembles C. nuttalli and C. meekianum in its obliquity and high umbones, but it has 10 to 15 more ribs and is relatively longer for its height." (Keen, 1954)
Occurrence in California.--Miocene: Cierbo and Neroly Sandstones, San Pablo Group (Keen, 1954).
Clinocardium (Clinocardium) meekianum meekianum (Gabb)
Cardium meekianum Gabb, 1866, p. 27, pl. 7, fig. 46. Arnold, 1908, p. 400, pl. 36, fig. 1. Arnold, 1910, p. 140, pl. 17, fig. 7. Clark, 1929, pl. 43, fig. 3.
Cerastoderma meekianum (Gabb). Stewart, 1930, p. 262-263, pl. 13, fig. 5.
Laevicardium (Cerastoderma) meekianum (Gabb). Grant and Gale, 1931, p. 310.
Clinocardium meekianum (Gabb). Keen, 1954, p. 327. Faustman, 1964, p. 119.
Clinocardium (Clinocardium) meekianum meekianum (Gabb). Roth, 1979, p. 301-303, pl. 5, figs. 7, 12.
Original description.-- "Shell, resembling C. corbis (Californianum and Nuttallii) but oblique; beaks large, strongly incurved and pointed forwards; anterior end prominent and broadly rounded; posterior end abruptly truncated and very oblique. Surface marked by 22 large radiating ribs; these ribs, in the young shell, are acute, becoming rounded as it increases in size, and ultimately becoming distinctly flattened on top; they are crossed by irregular, curved, subsquamose plates which towards the beaks lose their lamellar character, and are represented by little tubercles; the posterior face of the shell is not costate, or the ribs are represented by only a few indistinct radiating lines; the interspaces between the ribs are narrow and flat, or concave."
Holotype.--ANSP 4497.
Type locality.--Eagle Prairie, Humboldt County, Calif. Wildcat Group, Pliocene and Pleistocene.
Supplementary description.--"Clinocardium meekianum meekianum has from 21 to 27 large radiating ribs, exclusive of obscure ribs on the posterior slope; most specimens, however, have either 22 or 23 ribs." (Roth, 1979)
Comparison.--"This species [meekianum] differs from C. coosensis (Dall) in being more oblique, in having fewer radiating ribs, and in the lack of sculpture on the submargins." (Weaver, 1942, p. 157)
Comments.--Roth (1979) described two new subspecies of Clinocardium meekianum in manuscript.
Occurrence in California.--Miocene and Pliocene: Etchegoin (Arnold, 1910; Martin 1916) and Tahana Member, Purisima (Addicott, 1969) Formations; Pliocene: Falor (Manning and Ogle, 1950), and Ohlson Ranch (Peck, 1960) Formations; Pliocene and Pleistocene: Merced (Arnold, 1908; Glen, 1959), and Rio Dell (Roth, 1979) Formations.
Clinocardium (Clinocardium) meekianum myrae Adegoke
Plate 3, figure 9; Plate 3; Plate 3 caption
Clinocardium meekianum (Gabb) myrae Adegoke, 1969, p. 117-118, pl. 3, figs. 7, 9; pl. 7, fig. 6.
Original description.--"Shell medium sized to large; oblique, inequilateral, rather elongate postero-ventrally, with a variable but generally roughly trigonal outline; posterior margin long and straight, slopes off at an angle of about 45; anterior dorsal margin short, about half length of posterior dorsal margin, lunule inconspicuous; beaks prominently developed, incurved and strongly prosogyrate, shell ornamented by 28 to 30 broadly rounded ribs with narrow interspaces and wavy concentric growth lines; concentric lamellae well developed on ribs of larger, adult specimens."
Holotype.--USNM 495345.
Type locality.--UC 250. Fresno County, Calif. Etchegoin Formation, Miocene and Pliocene.
Supplementary description.--"This new subspecies [myrae] is characterized by its elongate trigonal outline, strongly convex valves with 28 to 30 radiating ribs.***Clinocardium meekianum (Gabb) has about 22 ribs, C. corbis (Martyn) 37 and C. coosense (Dall) 44 to 49." (Adegoke, 1969, p. 118)
Comparison.--"All specimens of Clinocardium***from the Etchegoin Formation of the Coalinga region are grossly similar to typical C. meekianum but differ primarily by having at least 28 ribs." (Adegoke, 1969, p. 118)
Occurrence in California.--Miocene and Pliocene: Etchegoin Formation (Adegoke, 1969).
Clinocardium (Clinocardium) coosense (Dall)
Cardium (Cerastoderma) coosense Dall, 1909, p. 118, pl. 13, figs. 3, 4.
Cardium coosense Dall. Arnold, 1910, p. 30.
Laevicardium (Cerastoderma) corbis (Martyn) var. coosense (Dall). Grant and Gale, 1931, p. 308.
Cerastoderma coosense (Dall). Weaver, 1942, p. 158.
Clinocardium coosense (Dall). Keen, 1954, p. 21.
Original description.--"Shell rounded, inflated, moderately thick, with prominent adjacent incurved umbones; anterior dorsal slope short, with a cordate smooth polished space (representing a lunule?) in front of them; posterior slope longer, with an elongate, rather narrow lanceolate escutcheon inclosing the ligamental nymphs (in the figured specimen 11.5 mm. long); base and ends rounded; surface with a well-marked polished periostracum which is frequently preserved in the fossils; sculpture of about 45 (44 to 49) radial ribs separated by narrower, partly channeled interspaces; the ribs on the anterior third of the shell are subangular, and the interspaces narrower, those on the posterior and middle part are flatter with the interspaces wider and more distinctly channeled; all the ribs are crossed by more or less evident incremental lines, and these are emphasized at three or four resting stages on the disk; the margins are slightly crenulated by the sculpture. Altitude, 50 mm.; latitude, 48.5 mm.; diameter, 36.5 mm., in the figured specimen."
Holotype.--USNM 153933.
Type locality.--Coos Bay, Oregon. Empire Formation, Miocene.
Comparison.--"C. meekianum is much more oblique [than coosense] and has the sculpture absent on the submargins; its ribs are also fewer." (Dall, 1909, p. 118)
"This species [coosense] may be distinguished from C. corbis (Martyn) in the larger number and greater prominence of the radiating ribs, and from C. meekianum in having a larger number of ribs. In the latter species the submarginal areas lack radial sculpture." (Weaver, 1942, p. 158)
Occurrence in California.--Miocene and Pliocene: Etchegoin and Purisima Formations (Grant and Gale, 1931); Pliocene and Pleistocene: Merced Formation and Wildcat Group (Grant and Gale, 1931).
Clinocardium (Clinocardium) nuttallii (Conrad)
Plate 4, figures 6, 7; Plate 4; Plate 4 caption
C[ardium]. nuttallii Conrad, 1837, p. 229, pl. 17, fig. 3.
Cerastoderma nuttallii (Conrad). Stewart, 1930, p. 259-260.
Clinocardium nuttalii (Conrad). Keen, 1936, p. 120. Fitch, 1953, p. 57, fig. 23. Addicott, 1966, p. C4, pl. 3, fig. 1. Hertlein and Grant, 1972, p. 261-262, pl. 46, fig. 21. Morris and others, 1980, p. 371, fig. 15.29.
Clinocardium (Clinocardium) nuttallii (Conrad, 1837). Coan, Scott, and Bernard, 2000, p. 351).
Cardium corbis (Martyn) of West Coast authors. Not Martyn 1788.
Cardium (Cerastoderma) corbis Martyn. Oldroyd, 1924, p. 142, pl. 34, figs. 1a, 1b.
Laevicardium (Cerastoderma) corbis Martyn. Grant and Gale, 1931, p. 307, pl. 19, figs. 14, 17.
Original description.--"Shell ovate-triangular, ventricose, thick; ribs thirty-four, regularly rounded, with prominent arched striae; umbo narrowed; summit very prominent; posterior slope much depressed; posterior margin straight, oblique, simply undulate; ligament margin declining; basal margin regularly arcuate; colour white; epidermis yellowish brown; lateral teeth thick and prominent; margin profoundly serrate. Height, three and a half inches."
Holotype.--ANSP 54036 (Keen, 1936)
Type locality.--"Inhabits muddy salt marshes, a few miles from the estuary of the Columbia River."
Supplementary description.--"Shell large; mature specimens decidedly longer posteriorly, with beaks nearer posterior end; younger specimens more equilateral. Sculpture of about 30 strong, rounded, radial ribs, nodose where crossed by commarginal riblets.***Hinge plate narrow; teeth prominent. Inner margin deeply crenulate. Length to 140 mm." (Coan, Scott, and Bernard, 2000, p. 351)
Comparison.--"Clinocardium nuttallii differs from the well known Pliocene species, C. meekianum Gabb, in the less oblique outline, less abrupt posterior truncation and in the more numerous, narrower radial ribs (about 34 rather than about 28) which continue on over the posterior truncation." (Hertlein and Grant, 1972, p. 261)
Occurrence in California.--Miocene: San Pablo Formation (Clark, 1915); Miocene and Pliocene: Etchegoin (Nomland, 1917) and Purisima (Martin, 1916) Formations; Pliocene and Pleistocene: Fernando (Arnold, 1907b; Eldridge and Arnold, 1907), Merced (Martin, 1914; Glen,1959), San Pedro (Arnold, 1903), and Santa Barbara (Grant and Gale, 1931) Formations; Pleistocene: Unnamed strata Baja California Norte (Valentine and Meade, 1961).
Habitat.--From low tide to 55 m (Hertlein and Grant, 1972, p. 261). Rare to relatively common, in mud or muddy sand of bays, sloughs, and estuaries***(Morris, 1980, p. 371) Intertidal to 30 m (Bernard, 1983, p. 39). Occasionally to 180 m in mud and sand, sometimes in dense colonies (Coan, Scott, and Bernard, 2000, p. 351). Living Bering Sea to San Diego, California.
Genus CLINOCARDIUM?
Subgenus CLINOCARDIUM?
Clinocardium? (Clinocardium?) dickersoni (Clark)
Plate 3, figures 7, 8; Plate 3; Plate 3 caption
Cardium dickersoni Clark, 1918, p. 140, pl. 13, figs. 11, 18.
Original description.--"Shell small, ventricose, subcircular, subequilatral; beaks central, not very conspicuous, slightly prosogyrous. Dorsal slopes straight or nearly so, the anterior slope apparently being somewhat the longer; posterior end broadly subtruncate; anterior end broadly and evenly rounded. Surface sculptured by about thirty prominent radial ribs, with interspaces averaging about the width of the ribs; tops of ribs on uneroded specimens V-shaped. Surface also covered by medium fine incremental lines, which on the less eroded portions of the shell are rather strongly imbricated."
Holotype.--UCMP 11207.
Type locality.--UC 1131. Contra Coasta County, Calif. San Ramon Formation, Miocene(?).
Comparison.--"This species [dickersoni] is very similar in outline and sculpturing to Cardium lincolnensis Weaver; it is somewhat smaller and lacks the narrow thread-like rib, described by Weaver [1916, p. 40] as occurring in the interspaces. Otherwise the two are very similar." (Clark, 1918, p. 140)
Occurrence in California.--Miocene(?): San Ramon Formation (Clark, 1918).
Subgenus KEENOCARDIUM Kafanov, 1975
"Beaks low; ribs about 28-65 in number; nodular tubercula absent on ridges of ribs***" (Kafanov, 1975)
Clinocardium (Keenocardium) lispum Roth and Talmadge
Clinocardium aff. C. pristinum Keen. Faustman, 1964, p. 120, pl. 1, fig. 7.
Clinocardium lispum Roth and Talmadge, 1975, p. 3-8, Fig. 1.
Clinocardium (Keenocardium) lispum Roth and Talmadge. Roth, 1979, p. 309.
Original description.--"A large, compressed, inequilateral Clinocardium with very numerous, fine, flat-topped ribs separated by linear interspaces.
"Shell moderately thick, ovate-trigonal, inequilateral, compressed, longer anteroposteriorly than high; beaks moderately inflated, strongly prosogyrous, situated about one-quarter of the distance from anterior extremity; surface sculptured with (on holotype) 59 smooth, rounded to flat-topped radial ribs, with the narrow interspaces linear over most of the disk but at posterior angulation and on extreme anterior portion of shell approaching the width of the ribs; ribs crossed by weak concentric threads near ventral margin. Posterior angulation marked by two or three more prominent ribs. Ribs on posterior slope not markedly weaker than remainder but more angular in section, the posterior facet of each rib sloping more gently than the anterior. Interior of valve reflecting surface sculpture. Hinge line long, hinge teeth not exposed in any specimens seen. Length of holotype 59.0 mm., height 51.6 mm., convexity (one valve) 15.7 mm."
Holotype.--UCMP 14152.
Type locality.--UC B-7643. NW 1/4, SE 1/4 sec. 5, T. 1 N., R. 1 E., Scotia, Calif. quadrangle (15 minute series, 1950 ed.). Rio Dell Formation, Wildcat Group, Pliocene and Pleistocene. Northern California.
Comparison.--"It [Clinocardium lispum] is clearly separable from Clinocardium pristinum. That species***has from 42 to 48 radial ribs and is more tumid and more nearly trigonal than C. lispum. ?Cardium (Cerastoderma) cf. corbis (Martyn) of Etherington (1931, page 77, plate 5, figure 11) from the Miocene Astoria Formation of Washington,***differs from C. lispum in being more orbicular, higher than long, and in having fewer ribs.
"Clinocardium hopkinsi Kanno, 1971, from the Poul Creek formation, upper Oligocene to lower Miocene of Alaska, may be the species most similar to Clinocardium lispum. It has fine, rather flat-topped radial ribs and concentric threading which is most strongly expressed near the margin. The beaks of C. hopkinsi, however, are less strongly prosogyrous than those of C. lispum, its ribs number about 40, and it is more nearly equilateral." (Roth and Talmadge, 1979)
Occurrence in California.--Pliocene and Pleistocene: Rio Dell Formation, Wildcat Group (Roth, 1979).
Clinocardium (Keenocardium) blandum (Gould)
Plate 3, figures 12, 13; Plate 3; Plate 3 caption
Cardium blandum Gould, 1850, p. 276. 1852, p. 418. 1859 [1861], pl. 36, figs. 534, 534a.
Clinocardium blandum (Gould). Keen, 1954, p. 21. Faustman, 1964, p. 119, pl. 1, figs. 11.
Clinocardium (Keenocardium) blandum (Gould). Roth, 1979, p. 309-310.
Clinocardium (Keenocardium) blandum (A.A. Gould, 1850). Coan, Scott, and Bernard, 2000, p. 353-354, pl. 73.
Original description.--
Holotype.--
Type locality.--
Supplementary description.--"Shell medium-sized, oval, somewhat longer posteriorly, inflated. Sculpture of numerous (about 45), low ribs sometimes overlain by feeble comarginal riblets; interspaces generally narrow. Folds on posterior slope weak. Beaks more inflated than in C. californiense***Inner shell margins shallowly crenulate. Length to 50 mm." (Coan, Scott, and Bernard, 2000, p. 353-354)
Comparison..--"Clinocardium blandum differs from C. lispum in its smaller size, lesser number of ribs, and greater prolongation of the posterior end." (Roth, 1979, p. 310)
Comments.--Coan, Scott, and Bernard (2000, p. 354) said they could not distringuish C. fucanum from C. blandum.
Geographic range.--Living: Pribilof Islands to middle California (Coan, Scott, and Bernard, 2000, p. 354); fossil: northern California.
Geologic range.--Pliocene to Holocene.
Occurrence in California.--Pliocene and Pleistocene: Rio Dell Formation (Roth, 1979).
Habitat.--10 to 50 m (Bernard, 1983); 20 to 80 m (Coan, Scott, and Bernard, 2000, p. 354). Living Pribilof Islands to middle California.
[Last updated June 28, 2002.]
To title page of Tertiary Marine Pelecypods
of California and Baja California
PAGE
PAGE 50
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