Tosapecten teradensis Nakazawa, 1952
NAKAZAWA, K. 1952. A study on the pelecypod-fauna of the Upper Triassic Nabae group in the northern part of Kyoto Prefecture, Japan. Part 1. Pectinids and limids. Memoirs of the College of Sience, University of Kyoto [Series B -Geology and Mineralogy], 20 (2): 95-106, pls. 7-10. [p. 100, pl. 7, figs. 7-9]
1952 Tosapecten teradensis Nakazawa, 1952
K. Nakazawa, 1952, plate 7.
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«Description: – Shell inequivalve, almost equilateral, suborbicular. Right valve moderately convex; antero- and postero-dorsal margins arcuate upward, anterodorsal margin a little longer than posterodorsal one; posterior ear rectangular trigonal, anterior ear not preserved. Surface ornamented with 10 ribs slightly narrower than interspaces; anterior and posterior submargins provided with 3 to 4 and 2 riblets respectively, which cannot be distinguished distinctly from main ribs. Left valve slightly convex, showing almost similar outline as right valve, but dorsal margin straighter; both ears subequal, triangular. Surface ornamented with 10 to 11 fine primary ribs intercalated by secondary striae; anterior submargin narrow and distinctly elevated, posterior one narrow and flat, surface of which is ornamented with several striae.
Both valves covered with distinct, close concentric growth-lines. Dimensions :
Comparison: – This species is smaller than Tosapecten nabaensis ane the right valve is less convex, and ribs weaker; in the left valve ribs are slender and flat-topped, and interspaces far wider and even, which enable one to distinguish it from any other species of Tosapecten.
Occurrence: – Lower part of N3 bed, Terada. (Loc. No. N-304, Reg. No. JM 10011-10013).» KEIJI NAKAZAWA, 1952
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