Cryptopecten Dall, Bartsch & Rehder, 1938
DALL, W. H., P. BARTSCH & H. A. REHDER. 1938. A manual of the Recent and fossil marine pelecypod mollusks of the Hawaiian Islands. Bernice P. Bishop Museum Bulletin, 153: i-iv, 1-233, pls. 1-58. [p. 93]
«Genus CRYPTOPECTEN, new genus
Shell of medium size, orbicular, laterally compressed, moderately thin; wings subequal, byssal sinus conspicuous, with a few short lamellar denticles on the lower border. Sculpture consists of radiating ribs which are very regularly lamellose, the laminations extending ventrally where they are met by the next lamination with which they fuse. They thus enclose a series of hollow chambers.
Type: Cryptopecten alli. This group appears to have an Indo-Pacific distribution, for we have seen specimens from the Philippines and Fiji, as well as Australia. It likewise has a fossil history.» WILLIAM HEALEY DALL, PAUL BARTSCH & HARALD ALFRED REHDER, 1938
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Cryptopecten alli, new species
(pI. 23, figs. 1-4, 7). |
«Diagnosis. Small to medium-sized Aequipectinini with valves highly variable in convexity, most species circular; laterally compressed; auricles almost equal; macrosculpture of 12–25 narrow, evenly lamellose radial plicae, interspaces with delicate imbricate scales; auricles sculptured with a few radial riblets; byssal notch relatively deep, functional ctenolium well-developed; internal rib carinae prominent; hinge with prominent resilial and dorsal teeth
Distribution. Lower Miocene–Recent. Indo-West Pacific and western Atlantic, living in the littoral to bathyal zones (see also Hayami, 1984: 116).
Discussion. Hertlein (1969: N357) treated Cryptopecten as a subgenus of Chlamys Röding, 1798, placed in the suprageneric Chlamys group. He also considered Gloripallium Iredale, 1939 to be a junior synonym of Cryptopecten.
Waller (1986: 40) elevated the extant Indo-West Pacific genus Gloripallium, and placed it in Decatopectinini of Pectininae. Cryptopecten, however, has morphological characters strongly resembling those of Aequipecten Fischer, 1886, and should be placed in the tribe Aequipectinini of Pedinae. Volachlamys is removed above from Aequipectinini to tribe Mimachlamydini. Waller (2011) included Chagrepecten Waller, 2011, Gurabopecten Waller, 2011, Leptopecten Verrill, 1897, Lindapecten Petuch, 1995, and Paraleptopecten Waller, 2011 in Aequipectinini. Other genera included in Aequipectinini are Aequipecten, Argopecten Monterosato, 1899, Cryptopecten and Haumea Dall, Bartsch & Rehder, 1938, and we now add Serratovola Habe, 1951.» DIJKSTRA, H. H. & A. G. BEU. 2018. Living scallops of Australia and adjacent waters (Mollusca: Bivalvia: Pectinoidea: Propeamussiidae, Cyclochlamydidae and Pectinidae). Records of the Australian Museum, 70 (2): 113-330, figs. 1-102. [p. 298]
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«OG14: Cryptopecten: The genetic results of Matsumoto (2003) show a close relation of vesiculosus to Pecten. It may well be, that this group is wrongly placed here.
Whereas Wagner (1989) basing on type material recognized 5 IND species, Raines & Poppe (2006) only recognized 4 IND species and changed Wagner’s synonymy. From the material at hand I am neither convinced that nux is the same as guendolenae, nor that hastingsii is the same as vesiculosus (HIG99) or the same as nux nuxnux (DIJ06). Instead, Wagner’s view and his synonymy are shared.
The quite common reddish, large C. vesiculosus from EChi and Japan and the flat type species C. bullatus from Natal to Hawaii do not pose problems.
The type of C. bernardi is depicted in HIG01 B473, the type of C. hastingsii Melvill, 1888 as well B472s. Following Wagner, these are considered identical. However, the
type locality of hastingsii, Japan is erroneous. Bernardi is not known from mainland Japan, where the much larger, less inflated vesiculosus (syn. hysginoides Melvill, 1888) occurs. C. hastingsii has the characteristic shape, color and auricles of bernardi. This species has been quite commonly found in the Marquesas, at below 20 m and has recently also been found in the Philippines, Aliguay, 100 m. It is the most inflated Cryptopecten, often deep red inside. Wagner separated nux from guendolenae. C. guendolenae is a rather common species found in the Red Sea to Natal and also well known from the Philippines. This is usually multicolored, moderately inflated, and smaller than bullatus. It is depicted as nux in Raines & Goto (2006 p. 315) or in Dijkstra & Kilburn (2001 fig. 50-51).
True C. nux is also a rare species. The type is depicted in Wagner (1989 fig. 6-7). It is more inflated than guendolenae, more solid and both auricles slightly larger, internally it is glossy, deep violet, deep yellow or deep orange, generally as the rather uniform outside colors. It usually has less than 20 ribs, whereas guendolenae has typically 22 ribs. It was originally described from Marquesas, but the type locality was restricted by Wagner to the Philippines. None was encountered diving in the Marquesas, although Tröndlé and Cosel reported it from there at a depth from 60-120 m. Specimens have been seen from the Philippines and from New Guinea. It is further reported from tropical Australia.»
HUBER, M. 2010. Compendium of Bivalves. 901 pp. + 1 CD-ROM. ConchBooks. Hackenheim, Germany. [p. 626]
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«Emended diagnosis of Cryptopecten.— Shell comparatively small-sized for pectinids, with height subequal to length, nearly acline but tending to become slightly prosocline in later growth stages. Convexity of shell variable among species, but right valve commonly more strongly inflated than left, the reverse being the case in early growth stages. Byssal notch moderately deep, provided with several denticles of ctcnolium. Wings moderate in size; anterior generally larger than posterior. Anterodorsal margin nearly straight, posterodorsal margin slightly concave, especially in later stages. Apical angle moderately large for pectinids. Disk margin scarcely gaped. Disk suborbicular, ornamented with 12 to 25 strong and simple radial ribs, and in later growth stages with a few fine threads on each interspace as well. Both lateral sides of radial ribs, and sometimes interspaces, covered with fine imbricated scales which enclose narrow hollow chambers. Wings of both valves with several radial ribs without hollow chambers. Early dissoconch marked with delicate Camptonectes-like striae, occurring from much earlier stage in left valve than right and disappearing before shell attains 4 mm in height. Coloration quite variable within each species, but commonly reddish brown. Left valve more darkly pigmented than right. Byssal wing of right valve almost invariably pale. Outer ligament area comparatively thin. Resilial pit small or moderate in size.
(...)
Origin of Cryptopecten.— Little has been studied about the ancestry of genus Cryptopecten. The earliest undoubted representative of this genus so far known is C. yanagawaensis from the lower Middle Miocene of Japan in the Pacific and C. nux from the Lower Miocene of Tanzania in the Indian Ocean. The two species, I presume, may have constituted independent stocks in different regions during Early-Middle Miocene times, but it is now difficult to determine which stock is parental and what their common ancestor is.
In this connection, however, it is worthy of notice that there are several Oligocene and Early Miocene pectinids which are considerably similar to the known species of Cryptopecten in general outline and some other shell characters. Such species are especially common in the Oligocene and Miocene of Iran, east Africa and Mediterranean region. Many of them were described under the subgeneric name of Aequipecten by Cox (1927, 1930) and Eames and Cox (1956). "Aequipecten" in Eames and Cox' sense appears to be a somewhat heterogeneous group, to which they referred, for example, Chlamys townsendi and Gloripallium pallium. Nevertheless, some Oligocene and Miocene species from this region may be actually ancestral to the true Recent representatives of Aequipecten in the Mediterranean and eastern Atlantic. It is generally admitted that the marine molluscan fauna of the western Indian Ocean was intimately connected with that of the Mediterranean region until the beginning of Miocene. For example, several species of Aequipecten from the Oligocene of Iran have also been known from Palestine, Italy and south France. After Early Miocene the Tethyan seaway was probably interrupted, and the provinciality of the two sea realms seems to have become clear. On the Indian side, Aequiptecten seems to have declined after Miocene and probably is not represented by any undoubted species in the present sea. Chlamys (Aequipecten) deltoidea Cox, 1,927, from the Lower Miocene of Pemba Island, Tanzania, C. (A.) iranica Eames and Cox, 1956, from the Lower Miocene of Iran, and C. (A.) kiwazinensis Eames and Cox, 1956, and C. (A.) pseudotjaringenensis Eames and Cox, 1956, from the Middle Miocene of Iran are rather unlike typical Recent species of Aequipecten, but resemble, though probably only superficially, Cryptopecten yanagawaensis and C. vesiculosus in outline and number of radial ribs. However, these Miocene species do not show any distinct hollow structure of radial ribs as is commonly seen in Cryptopecten. Further studies of Paleogene and Miocene pectinids in the Tethyan region seem to be necessary in order to determine the phylogenetic relation between Aequipecten and Cryptopecten.» HAYAMI, I. 1984. Natural history and evolution of Cryptopecten (A Cenozoic-Recent Pectinid Genus). The University Museum, The University of Tokyo, Bulletin, 24: 1-149, pls. 1-13. [p. 90, 91, 95, 96]
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