Azumapecten farreri (Jones & Preston, 1904)
JONES, S. K. H. & H. B. PRESTON. 1904. List of Mollusca collected during the Commission of H.S.M. "Waterwitch" in the China Seas, 1900-1903, with descriptions of New species. Proceedings of the Malacological Society of London, 6: 138-151. [p. 149, text fig.]
1850 Pecten asperulatus Adams & Reeve, 1850
1861 Pecten laetus Gould, 1861
1904 Pecten farreri Jones & Preston, 1904
1932 Chlamys farreri nipponensis Kuroda, 1932 [nomen novum pro Pecten laetus Gould, 1861]
1932 Chlamys farreri akazara Kuroda, 1932
1993 Chlamys nantiensis Bernard, Cai & Morton, 1993 [nomen novum pro Pecten laetus Gould, 1861]
1861 Pecten laetus Gould, 1861
1904 Pecten farreri Jones & Preston, 1904
1932 Chlamys farreri nipponensis Kuroda, 1932 [nomen novum pro Pecten laetus Gould, 1861]
1932 Chlamys farreri akazara Kuroda, 1932
1993 Chlamys nantiensis Bernard, Cai & Morton, 1993 [nomen novum pro Pecten laetus Gould, 1861]
Pecten laetus, GouId; M. Yokoyama, 1922, Fossils from the upper Musashino of Kazusa and Shimosa, plate 14, figure 26.
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«Shell orbicular, equilateral, scaly, the left valve somewhat more convex than the right, the former bearing 10 coarse costae, the latter about 25, between which, on both valves, appear numerous finer riblets; auriculae very unequal, the anterior large, descending in a curve, the posterior comparatively small, forming approximately an obtuse-angled triangle, both sculptured with scaly riblets; colour dirty white, banded and mottled, especially on the left valve, with rich purple brown. Long. 81, lat. 75 mm.
Hab.— Shi Tao, Shantung. The nearest ally of this handsome species appears to be Pecten Iaetus from Japan, from which, however, it differs in being somewhat more orbicular, in the greater number of the costae in both valves, on which the scales are much smaller and further apart, and in the shape of the auriculae, the anterior being considerably more curved, while the posterior descends more abruptly and without the curve noticeable in P. Iaetus.»
SURGEON K. HURLSTONE JONES & H. B. PRESTON, 1904
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«Remarks. Further type material is housed in other museums: Two syntypes BMNH 1903.12.20.6–7 (pairs of articulated valves, of which the largest shell is the figured specimen in the original description); syntype MNHN (not registered, pair of articulated valves); two syntypes NMW 19.141.794 (pairs of articulated valves).
The current taxonomic position of this species is Azumapecten farreri (Jones & Preston, 1904), placed in the family Pectinidae. It lives along the coasts of northern China, Korea, and eastern Russia and in Japanese waters in littoral and sublittoral depths.» DIJKSTRA, H. H. & F. KÖHLER. 2008. An annotated catalogue of Recent Pectinoidea (Mollusca, Pectinidae and Propeamussiidae) type material in the Museum of Natural History, Humboldt University, Berlin. Zoosystematics and Evolution, 84 (1): 31-44, figs. 1-4. [p. 37]
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Syntype of Pecten (Chlamys) farreri ZMB Moll. 55.347; H. H. Dijkstra & F. Köhler, 2008, An annotated catalogue of Recent Pectinoidea (Mollusca, Pectinidae and Propeamussiidae) type material in the Museum of Natural History, Humboldt University, Berlin, figure 3a.
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«Chlamys farreri (Jones & Preston, 1904) (PI. 2, Figs . 7, 8), which is considered to be a valuable scallop species in Japan (Ventilla, 1982, p. 326), superficially resembles members of the C. islandica complex in form and size but differs in a number of respects. The shell of C. farreri tends to be modified in relation to its enlarged byssal opening. Both anterior auricles are enlarged in dorsoventral dimension, particularly the left anterior auricle, which serves as a shield over the deep byssal notch below the right anterior auricle. The entire shell tends to be somewhat opisthocline, appearing as though it is twisted around the byssal opening. The right valve is less convex than the left and may indeed be quite flat, showing irregularities that indicate close apposition to the substrate. C. farreri is known to live attached by its byssus to rocks and gravel from the tide mark down to 60 m (Kuroda, et al., 1971) in contrast to C. islandica, which tends to live in deeper water and is possibly more mobile. (Gruffydd (1976) determined that every member of a population of C. islandica in Norway moved on the average of once every 31 days.) C. farreri also differs from members of the C. islandica complex in the details of its ribbing pattern and most importantly in its lack of a foliated calcite reentry within the pallial line on its shell interior. As stated in the preceding section on morphology, a foliated calcite reentry appears to be an adaptation to life in cool water. The absence of this reentry in C. farreri suggests that this species probably originated in a warmer water environment and has only recently become adapted to a cooler regime.
The species name Chlamys farreri (Jones & Preston, 1904) was originally based on a specimen from the Chinese coast (Shantung Province) and was thought by Jones and Preston (1904) to be distinguishable from members of a very similar species in Japan. Kuroda (1932) subsequently named the Japanese populations as two subspecies, C. farreri nipponensis in southern Japan and C. farreri akazara in northern Japan. Later workers (Masuda, 1962; Kuroda, et al., 1971) have synonymized Kuroda's Japanese subspecies but continue to recognize the Japanese populations as distinct from C. farreri, sensu stricto, along Chinese coasts. Masuda (1962) gave the range of "C. nipponensis" as from 31° N to 44° N in the Japan Sea, and Kuroda, et al. (1971) mentioned the presence of this subspecies in Korea and North China. My own study of variation among Japanese and Chinese specimens suggests that all of these can be regarded as a single species, C. farreri, because of morphological intergradation. The nearest living relatives of C. farreri are quite clearly C. squamata (Gmelin, 1791), a common species ranging from southern Japan through the Philippines and Indonesia, and C. livida (Lamarck, 1819), which occurs mainly off eastern and southern Australia. Both of these species share with C. farreri the large byssal notch and associated shell features, including flattening and common distortion of the right valve. The entry of C. farreri into cooler waters at the northern end of its range appears to have been accomplished in the late Pliocene, this being the lower end of its strati graphic range in Japan (Masuda, 1962).» WALLER,
T. R. 1991. Evolutionary relationships among commercial scallops
(Mollusca: Bivalvia: Pectinidae). In: Shumway S. E. (ed.), Scallops:
biology, ecology and aquaculture. Developments in Aquaculture and
Fisheries Science, Elsevier, Amsterdam, 21: 1-73, pls. 1-8. [p. 23, 24]
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Chlamys farreri (Jones & Preston, 1904); T. R. Waller, 1991, Evolutionary relationships among commercial scallops, plate 2, figures 7, 8.
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Remarks: — Chlamys farreri (Jones and Preston) (Kuroda, 1932, p. 91, fig. 109), a Recent species of Shantung, China, is related to the present species, but it can be distinguished from nipponensis by its very unequal radial ribs which are more prominently scaled in the right valve and by the left valve having the radial ribs very unequal in strength. The present species is also related to Chlamys iwakiana (Yokoyama), but it has less inflated right valve, larger number of somewhat unequal radial ribs in which some radials divide into two or three, rather distinct, finely scaled riblets ventrally, the auricles which are a little inclined anteriorly upwards, and by the left valve having the unequal, prominent radial ribs.
The present species was first described by Kuroda as a subspecies of Chlamys farreri (Jones and Preston) (1904) for the specimens hitherto recorded under the name of Chlamys laetus (Gould) in Japan. At the same time Kuroda described Chlamys farreri akazara as a northern form of nipponensis. However, by the examination of numerous specimens the writer considers that Kuroda's akazara is a synonym of nipponensis, though the surface sculptures of the northern from of nipponensis somewhat differ from those of the southern form in the strength of the radial ribs. The occurrence of this species is restricted to the Late Pliocene to Recent. Therefore, from the morphological characters it seems that Chlamys iwakiana or Chlamys daishakaensis may be the ancestral form of the present species. Type locality: -- Japan. Recent. Distribution: -- Shibikawa formation, Akita Prefecture; Setana formation (upper), Hokkaido; Naganuma and Miyata formations, Kanagawa Prefecture; Katori, Umegase, Narita, Sanuki and Kiyokawa formations, Chiba Prefecture; Hiratoko formation, Ishikawa Prefecture; Tokyo formation, Tokyo Metropolis, etc.; Living in the Pacific (31° -42°N.) and Japan Sea (36°-44°N.): Late Pliocene to Recent. Occurrence: -- Few in the medium-grained sandstone of the Shibikawa formation; common in the sand and granule of the Hiratoko formation. MASUDA,
K. 1962. Tertiary Pectinidae of Japan. Science Reports of the Tohoku
University [2nd. Series - Geology], 33 (2): 117-238, pls. 18-27. [p. 181]
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Chlamys nipponensis (Kuroda); K. Masuda, 1962, Tertiary Pectinidae of Japan, plate 20, figure 10.
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