Superclass Crustacea

Class Ostracoda-

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-Species Descripions-


Beyrichia bella Walcott, 1884 - Description from Walcott, 1884

Beyrichia bella Walcott, 1883, p. 7, pl. 17, fig. 11; Walcott, 1884, p. 213, pl. 17, figs. 11, 11a; Bassler, 1915, p. 120.

Description: Carapace large as compared with associated species. The hinge line is straight and shorter than the length of the valves, each end projecting. The center of the valve is strongly convex, and separated from the margin by a narrow channel; a strong deep sulcus crosses the valve obliquely from the dorsal to the ventral margin, separating a large convex lobe on the anterior half: a second sulcus, not as deep as the anterior, crosses the posterior third of the dorsal margin, and unites with the anterior sulcus two-thirds of the distance between the dorsal and ventral margins, separating a subtriangular lobe adjoining the dorsal border and a narrower elongate strongly convex lobe on the posterior portion; this lobe is crossed by a transverse furrow near the dorsal end, which separates a small depressed lobe within the postero-dorsal angle. Surface finely granulose under a strong magnifying power.


            Beyrichia bella, MCZ 109611                  
MCZ 109611: Holotype, 3mm long

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Ctenobolbina ciliata (Emmons, 1855) - Description from Ulrich and Bassler, 1908

Beyrichia ciliata Emmons, 1855, p. 219, text fig. 74c; Miller, 1875, p. 351; Lesley, 1889, p. 89; Jones, 1890, p. 19, pl. 3, 4, figs. 12-16, 16-18.
Beyrichia tumifrons Hall, 1871, p. 7, pl. 4, fig. 11; Hall, 1872, p. 231, pl. 8, fig. 11; Miller, 1874, p. 119, 354; Hall and Whitfield, 1875, p. 102, pl. 4, fig. 8.
Ctenobolbina ciliata Ulrich, 1890, p. 108, pl. 7, figs. 1a, b; Andersson, 1893, p. 128; Ruedemann, 1901, p. 575, pl. 2, figs. 8, 9; Ulrich and Bassler, 1908, p. 282, text fig. 7, pl. 40, fogs. 1, 2; Grabau and Shimmer, 1910, p. 353, text fig. 1660 t, t’; Wade, 1911, p. 452; Bassler in Zittel, 1913, p. 738, fig. 1425e; Bassler, 1915, p. 297; Ulrich and Bassler, 1923, p. 310, 311, text fig. 20 (fig. 4); Foerste, 1924, p. 252, pl. 45, fig. 2; Kirk, 1928, p. 419.

Description of Genus: Carapace small, usually less than 2mm in length, subquadrate or subovate in outline, the hinge line long and straight; posterior two-fifths more or less decidedly bulbous or subglobular in the typical section of the genus, but in the C. subcrassa section the corresponding parts of the carapace are smaller and usually of lesser thickness than certain portions in front of it. In the latter section a small node (the homologue of the median lobe of Beyrichia) is sometimes distinguishable on the inner slope of the posterior lobe. One deep, long, narrow, generally curved and more or less oblique sulcus extends from the middle of the dorsal edge toward the post-ventral angle, occasionally reaching the border. Area in front of median sulcus either simply convex or divided by a shallower furrow usually paralleling the main sulcus. Valves equal, the free edges thick, the contact margins generally concealed, partly or wholly, in a lateral view, by a variously modified overhanging border. Surface granulose, smooth, or punctate.


      Ctenobolbina ciliata, MCZ 145794 Ctenobolbina ciliata, MCZ 145795        
MCZ 145794: 2.5mm wide
MCZ 145795: 1.5mm wide

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Eoleperditia sp. Swartz, 1949 - Description from Benson et al., 1961

Description of Genus: Nonsulcate, unornamented, thickshelled; right valve overlapping margin of left valve, non-denticulate hinge, no marginal flattening; large adductor muscle scar composed of numerous secondary scars, other muscle scars and venose lines commonly present, lacking subocular chevron mark, prongs on inner margin of right valve.


            Eoleperditia sp., MCZ 145792                  
MCZ 145792: 8mm wide

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Leperditid - Description from Benson et. al, 1961

Description of Order: Hinge long, straight; shell thick, well calcified; surface usually smooth, some some finely ornamented to nodose; valves strongly unequal to subequal; adductor muscle scar large, composed of numerous secondary elements.


            Leperditid, MCZ 145793                  
MCZ 145793: 3.5mm wide

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Tetradella subquadrans Ulrich, 1890 - Description from Ulrich and Bassler, 1908.

Tetradella subquadrans Ulrich, 1890, p. 115, text figs. 2a-c; Ulrich and Bassler, 1908, p. 307, pl. 39, figs. 1-3; Bassler, 1915, p. 1264.

Description of Genus: Family Tetradellidae. Carapace small, 1mm to 2mm long, equivalved, never tumid, somewhat oblong, varying from subquadrate to subovate, with the hinge line straight. Valves depressed-convex, deeply trisulcate, the furrows separating four more or less sharply elevated ridges. As a rule the ridges connect ventrally, but are quit distinct at their dorsal extremities, the result being a semielliptical submarginal ridge with two simple or double, equal or unequal, and less curved ridges within the closed space. These inner ridges commonly unite with the ventral part of the marginal ridge and extend upward from it toward the dorsal edge, the posterior one often failing to reach it. Free margins usually with a simple flattened border, which in certain cases extends beyond and conceals thickened contact edges. Surface of valves usually smooth, occasionally minutely granose.


            Tetradella subquadrans, MCZ 145797                  
MCZ 145797: 1mm wide

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