Tosapecten Kobayashi & Ichikawa, 1949
KOBAYASHI, T. & K. ICHIKAWA. 1949. Tosapecten, gen. nov. and other Upper Triassic Pectinidae from the Sakawa basin in Shikoku, Japan. Japanese Journal of Geology and Geography, 21 (1-4): 163-176, pI. 5. [p. 166]
S. Ros-Franch, A. Márquez-Aliaga & S. E. Damborenea, 2014, Comprehensive database on Induan (Lower Triassic) to Sinemurian (Lower Jurassic) marine bivalve genera and their paleobiogeographic record, figure 36.
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«Genus TOSAPECTEN Kobayashi & Ichikawa, 1949b, p. 166
Type species.— Pecten (Velopecten) suzukii Kobayashi, 1931, p. 258.
Remarks.— Although Kobayashi and Ichikawa (1949b) proposed Tosapecten within the family Pectinidae, Cox and others (1969) considered it to be a subgenus of Weyla Böhm, 1922. Currently, almost all authors (Hayami, 1975; Milova, 1976; J. Chen, 1982a; Okuneva, 1985; Damborenea, 1987b; Tanaka, 1989; Waller in Waller & Stanley, 2005; Waller, 2006) regard it as a distinct genus, separate from Weyla.
According to Waller (in Waller & Stanley, 2005), Tosapecten includes two subgenera, T. (Tosapecten) and T. (Indigiropecten) Trushchelev, 1984. Stratigraphic range.— Upper Triassic (Carnian–Rhaetian) (Kobayashi & Ichikawa, 1949b; Milova, 1976). Cox and others (1969) stated that the genus was known from the Upper Triassic of Japan. Subsequently, it was also reported from Siberia (Kobayashi & Tamura, 1983b). It was known throughout the Carnian and Norian in Japan (see paleogeographic distribution, below). We lack information on the Siberian records; we could only check the Norian occurrence in Okuneva (1985). Milova (1976) reported Tosapecten subhiemalis wittnburgi n. subsp. from upper Norian–Rhaetian beds. Some biostratigraphic papers mentioned the presence of Tosapecten from latest Triassic times (Kurushin, 1990; Polubotko & Repin, 1990; Zakharov & others, 1997), referring to Tosapecten efimovae Polubotko, 1966.
Paleogeographic distribution.— Circumpacific and Boreal (Fig. 36). Tosapecten was mainly distributed through the northern Circumpacific and Boreal domains.
Circumpacific domain: Late Triassic: Carnian of Japan (Nakazawa, 1952; Ando, 1988); Carnian–Norian of Japan (Kobayashi & Ichikawa, 1949b; Tokuyama, 1959b; Hayami, 1975; Tanaka, 1989; Onoue & Tanaka, 2005); Norian of Japan (Nakazawa, 1963), ?Oregon (United States) (Newton in Newton & others, 1987; Newton, 1988). Boreal domain: Late Triassic: Carnian of northeastern Russia (Bychkov & others, 1976), Primorie (Kiparisova, 1972); Norian of Siberia (Okuneva, 1985); Norian–Rhaetian of northeastern Russia (Milova, 1976); Rhaetian of northeastern of Siberia (Bychkov & others, 1976; McRoberts, 2010). Paleoautoecology.— B, E, S, Epi, Sed; By. In all species assigned to Tosapecten, a byssal notch is observed, and they have unequal auricles (see description and figures in the published literature, listed above). Like most pectinids, they lived epibyssate.
Mineralogy.— Bimineralic (Carter, 1990a, p. 260). There are no data on Tosapecten shell microstructure. Bimineralic mineralogy is assumed, as in the other members of the family Pectinidae.»
ROS-FRANCH, S., A. MÁRQUEZ-ALIAGA & S. E. DAMBORENEA. 2014. Comprehensive database on Induan (Lower Triassic) to Sinemurian (Lower Jurassic) marine bivalve genera and their paleobiogeographic record. Paleontological Contributions, 8: 3-219, figs. 1-61. [p. 103, 104]
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