Terebratalia tisimana (Nomura et Hatai, 1936)   Diestothyris tisimana Nomura, Hatai, 1936: 131–134, text-figs. 1–10. Tisimania tisimana Hatai, 1938: 203. Diestothyris (Tisimania) tisimana Hatai, 1940: 274–275, pl. 4, figs. 1–4, 7, 9. Terebratalia coreanica occidentis Konzhukova, 1957: 29–31, pl. 3, figs. 1–12, pl.4, figs. 1–4. Terebratalia coreanica ochotica Konzhukova, 1957: 31–35, pl. 4, figs. 5–8, pl. 5, figs. 1–4. Terebratalia coreanica beringiana Konzhukova, 1957: 35–36, pl. 5, figs. 5–8. Terebratalia tisimana Zezina, 1970: 446–449. Terebratalia (Tisimania) tisimana Zezina, 1997: 66–67, figs. 41, 42. Description. Shell of gray colour with length up to 42 mm has thick valves, pores are very dense. Anterior commissure is straight (rectimarginate). Deltidial plates do not meet each other and foramen is open anteriorly. Outer surface of shell is smooth with concentric lines of growth at the anterior part. Pedicle collar is wide, striped with longitudinal lines. Dental plates are weakened near the bottom of pedal valve. Cardinal process is narrow, transversal and covered with small numerous furrows. Middle septum does not reach hinge margin and stretches anteriorly up to half of the brachial valve. Distribution. The species is distributed from the Povorotny Cap (Peter the Great Bay) to the north along the coast of Asia to Shelikhov Bay. It is known well near western and eastern coast of Kamchatka, around Middle and Northern Kuril Islands, near the Commander Islands and off the Unimak (Aleutian Islands). References: The World Register of Marine Species
Terebratalia coreanica (Adams et Reeve, 1850)  Terebratula coreanica Adams, Reeve, 1850: 71, pl. 21, fig. 3; Davidson, 1887: 81–83, pl. 13, figs. 3–4. Terebratalia coreanica Dall, 1920: 345. Terebratalia coreanica coreanica Konzhukova, 1957: 27–28, pl.2, figs. 8–15. Description. Shells are up to 46 mm in diameter, round or oval in length direction. Brachial valve is concave along middle line, pedal valve has proper keel-shaped prominence. Deltidial plates are triangular, they meet each other anteriorly but never conjunct. Shell is entirely orange-red or is coloured with white and red radial rays. Concentric lines of growth are marked with intensive red tint. Distribution. Geographic range of the species is stretched along Pacific coast of Asia from Quingdao (China) to Rynda Bay (Primorye), the species is known also near southern-east coast of Sakhalin and near the Japanese Islands from the Tsugaru Strait to the Korea Strait. A single specimen was found near the coast of Primorye (Rynda Bay) without data on the depth (Konzhukova, 1957). Ecological data. The species lives at the depths of 13–287 m. References: The World Register of Marine Species
Coptothyris adamsi Davidson, 1871   Terebratula grayi Davidson, 1852: 76 (preocc. Davidson, 1848, fide Allan, 1947). Magasella adamsi Davidson, 1871: 307. Waldheimia grayi Davidson, 1886: 54, pl. 10, fig. 4. Coptothyris grayi Thomson, 1927: 247; Markovskaya-Avdeeva, 1976: 113, figs. 264, 265. Coptothyris adamsi Allan, 1947: 497–498; Zezina, 1997: 68. Description. Large roughly ribbed shells, variable in shape from round or almost pentagonal to semicircular and triangular, from oval to transversely stretched. Hinge margin is straight or slightly curved, being longer or shorter than the width of shell. Beak is short, almost straight, foramen is large transversely oval, deltidial plates are triangular disjunct, usually destructed. Side ribs of beak are well expressed and form triangular almost plain area. Rough radial ribs bifurcate near the shell margins, concentric growth-lines are well seen marked out with intensive rose colour on the general yellowish background of shell. Cardinal process is narrow transversal, hinge platform fused with middle septum, which reaches half of shell-length in young specimens, but is reduced in adults. Free loop in adults stretches anteriorly to 4/5 of the length of brachial valve. Distribution. The species is known around the Japanese Islands from southern shores of Hokkaido to Kyushu and along continental slopes of Asia from the Korea Straight to 48° N (Konzhukova, 1957). Ecological data. Vertical range is 2–353 m. The species is known well in Peter the Great Bay from Furugelm Island to Povorotnyi Cap at the depths of 3–20 m, but it is not numerous. Maximal density 4 sp./m2 is found in Vostok Bay at the of depth 3–4 m. Beautiful shells of the species often become a prey of tourists and fanciers of marine rarities. At the same time, the species is subtropical endemic with confined geographic range, and its ontogenesis has principal significance for systematics. So Coptothyris adamsi is included in the Red Book of Russian Federation (Zezina, 2001). References: The World Register of Marine Species
Genus Terebratalia Beecher, 1893Type species: Terebratula transversa Sowerby, 1846 (recent north-Pacific species). Shells are smooth. Anterior commissure is straight (rectimarginate) or convex to pedal valve (sulcate). Deltidial plates are usually disjunct, rarely meet each other but never conjunct. Pedicle collar is short overhung; dental plates are weak. There are thickenings between margins of hinge-sockets and cardinal process. Descending branches of brachial loop have thin connection with median septum during all life of specimen. Systematic of the genus is not studied well. There are two species in Russian waters of the Sea of Japan: Terebratalia coreanica and T. tisimana. Key to species of the genus Terebratalia 1(2). Shells are gray (sometime rose-pink) without any traces of radial design T. tisimana 2(1). Shells are orange and red with intensive red fan-shaped radial rays T. coreanica
Genus Coptothyris Jackson, 1918Type species: Magasella adamsi Davidson, 1871. Shells are round or transversely oval in plan, multiplicate, with rough irregular radial ribs. Pedal valve is more convex than brachial one, which can be plane and even concave. Anterior commissure is convex to pedal valve (sulcate). Hinge margin is long and slightly curved. Dental plates are strong. Middle septum in brachial valve is reduced in adults. Loop of brachial skeleton is ribbon-shaped and free. There is a single recent species in the genus.
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