Crassadoma multistriata (Poli, 1795)
POLI, J. X. 1795. Testacea utriusque Siciliae eorumque historia et anatome tabulis aeneis illustrata. Tomus Secundus. 75-264 p., i-lxxvi, pls. 19-39. Regio Typographeio, Parma.[p. 164, pl. 28, fig. 14]
1795 Ostrea multistriata Poli, 1795
1853 Pecten tinctus Reeve, 1853
1853 Pecten textilis Reeve, 1853
1853 Pecten effulgens Reeve, 1853
1878 Pecten nimius Fontannes, 1878
1898 Pecten aculeatulus Almera & Bofill, 1898
1853 Pecten tinctus Reeve, 1853
1853 Pecten textilis Reeve, 1853
1853 Pecten effulgens Reeve, 1853
1878 Pecten nimius Fontannes, 1878
1898 Pecten aculeatulus Almera & Bofill, 1898
J. X. Poli, 1795, plate 28.
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«Testae characteres. Concha ovata, aequivalvis, radiis circiter quinquaginta exilissimis, confertis, muricatis; auriculis inaequalibus, cardine subobliquo.
Testae descriptio. Concha ovata, aequivalvis, ac aequilatera. Valvae tenues radiis circiter quinquaginta, exilissimis, densatis discriminantur, qui, perinde ac testa universa, aculeis exiguis, atque eonfertis, nonnisi lente vitrea conspiciendis, vel contrectatu sentiendis, horrescunt. Auriculae inaequales: cardo vix obliquus. Tota concha cinnabarina, vel rosea, punctis albescentibus depicta est. Inter Ostream hanc, et Variam tanta adfinitas intercedit, ut nonnisi ob radiorum numerum, atque aculeorum magnitudinem differant. Haec, licet rariuscula, cum illa, et Sanguinea promiscue vivit, eumdemque Animantem includit.» JOSEPHUS XAVERIUS POLI, 1795
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«Discussion. The specimens are ornamented with about 60 narrow ribs, which are bifurcated in the RV and composed of two intercalating sets of different strength in the left valve; moreover, they are characterised by anti-marginal microsculpture in the rib interspaces, a deep byssal notch and 7 scaly ribs on the strongly protruding anterior ear of the right valve. Thus, the specimens can be clearly attributed to Talochlamys multistriata (Poli, 1795), a long-lived, highly variable species that is the only representative of its genus in European Neogene deposits. We follow Dijkstra & Kilburn (2001) in combining this species with the genus Talochlamys Iredale, 1929. The latter authors proved the previous recombination by Waller (1993, 1996) with the NE Pacific genus Crassadoma Bernard, 1986 to be erroneus.
Distribution. This is a common shallow water species in the Mediterranean, Paratethys and SE Atlantic since the Burdigalian (Lower Miocene). Today it occurs in the Mediterranean and along the temperate eastern Atlantic coast, and in the SW Indian Ocean where it is restricted to South Africa (Dijkstra & Kilburn, 2001). It lives byssally attached to primary and secondary hardgrounds from the subtidal zone to the inner continental shelf (Dijkstra & Kilburn, 2001).» HARZHAUSER, M., M. REUTER, O. MANDIC, S. SCHNEIDER W. E. PILLER & M. BRANDANO. 2013. "Pseudo-Sarmatian" mollusc assemblages from the Early Messinian oolite shoals of Sicily (Italy). Rivista Italiana di Paleontologia e Stratigraphia, 119 (3): 351-386, pls.1-4. [p. 369]
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Talochlamys multistriata (Poli, 1795); M. Hartzhauser et al., 2013, "Pseudo-Sarmatian" mollusc assemblages from the Early Messinian oolite shoals of Sicily, plate 3, figure 3.
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«Description:
Medium sized, fragile, inequilateral and inequivalve shell. Left valve about 50% flatter than right one. Disc drop-shaped, asymmetrical, elongated on the anterior side. Ornament consisting of about forty radial ribs, which are irregularly stronger or weaker. They become about as broad as the intercostal spaces and they are covered by a large number of sharp, triangular, hollow spines. Concentric omament is lacking, other than some growth lines. Anterior auricle with rather shallow byssal notch, about twice as broad as posterior one. Together they comprise two thirds of the corrplete shell length. Area between disc and anterior auricle covered with irregular, scaly concentric ornament. Auricle with about seven strong radial ribs, which becor¡e heavier near the upper rnargin. There, they are covered with scales. Posterior auricle markedly concave against the disc, lacking scales in between. About five weak ribs are present on this auricle; they lack scales and spines. Hinge line straight along anterior ear, curving downward at posterior end. Cardinal crura very clear. Ligarrent pit bluntly triangular. Ctenoliurn with five clear teeth. Outside rib ornament only visible in the interior near the ventral margin. Muscle impression rather large and oval shaped. Discussion: GIANUZZI-SAVELLI et al. (2001) clearly showed the difference between this species and Crassadoma pusio (LINNAEUS, 1758), which is an irregularly shaped species, adhering to substrates like white coral. Occurrence: Crassadoma m. multistriata (LINNAEUS, 1758) is found at Doel in the Kattendijk Formation basal gravel. It is a very common species in the Kattendijk Fonnation of Kallo, especially in the Petaloconchus level. Frorn the basal crag of the Oorderen Sand Member however, it is replaced by the next subspecies [Crassadoma multistriata harmeri (Van Regteren Altena, 1937)] . The distribution in the British and Dutch Pliocene of both subspecies is not yet fully clear, but both were found in Dutch beach material. The oldest form of the C. pusio-group is Crassadoma pusio perstriata (SACCO, 1897), which is found in the Early and Middle Miocene of the Mediterranean and France C. multistriata is also present in the Middle Miocene of the western Paratethys, as demonstrated by KAUTSKY (1928), FRIEDBERG (1936) and HÖRNES (1870), but the species is missing in the eastern part according to STUDENCKA et al. (1998). It is unclear to which subspecies the paratethyan material slrould be assigned. In any case, C. m. multistriata is present from the French Late Miocene onward. It is also found in Pliocene deposits frorr the Iberian peninsula and from the Mediterranean. No Miocene records are known from the North Sea basin, the species occurs there only in the Early Pliocene. Recent C. multistriata is known from the British Isles, along the European and West-African coast to Cape of Good Hope and from the Mediterranean; it lives on coarse sand and gravel, between 10 and 180 rn. Atlantic populations seem to live fixed on substrates, while the Mediterranean ones are free swimrning. No specirnens shaped as their substrate have however been found in Kallo, as would be expected atnong attached Pectinidae.» MARQUET, R., P. MOERDIJK & F. A. D. VAN NIEULANDE. 2002. The Neogene Amphineura and Bivalvia (Protobranchia and Pteromorphia) from Kallo and Doel (Oostvlaanderen, Belgium). Paleontos, 2: 99pp., 34 plates. [p. 58]
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Crassadoma multistriata multistriata (Poli, 1795); R. Marquet et al., 2002, The Neogene Amphineura and Bivalvia from Kallo and Doel, plate 28. figure 1.
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«Remarks [Talochlamys multistriata (Poli, 1795), comb. n.]: The present species is variable in outline and sculpture, and often distorted or deformed from its habit of nestling in crevices.
Southeastern Atlantic and South African specimens usually have a narrower umbonal angle (ca. 80-85°) and larger anterior auricles with more numerous radial riblets (ca. 12–17) than typical specimens from Mediterranean waters, but sculpture and microsculpture are identical. Intermediate variation is also observed (see Waller 1993: 213). Although Waller (1993) also recorded T. multistriata from ‘off southern Mozambique’, based on material housed in the USNM, our data does not indicate a range extending anywhere that far north or into the tropical waters of SE Africa. Perhaps this material is mislocalised or based on examples of the superficially similar Laevichlamys deliciosa. Although multistriata has been referred to Chlamys by most authors (see synonymy), it lacks the shagreened interstitial microsculpture of that genus. Recently Waller (1993) transferred multistriata to Crassadoma Bernard, 1986, in the subfamily Chlamydinae. The latter genus occurs in the northeastern Pacific, and no fossil or Holocene Crassadoma species appear to be known from the Indo-West Pacific region (Waller 1993). Adults of Crassadoma are cemented by the RV, and species are sculptured with prominent widely spaced intercostal commarginal lamellae; intercostal antimarginal striae are only produced on the flanks of the ribs near the posterior margin, most prominently on the RV. Talochlamys species are known from the Holocene of the Indo-Pacific (Dijkstra 1993: 24-28; Beu 1995: 17-19). In this genus antimarginal intercostal striae are developed throughout ontogeny and closely spaced intercostal commarginal lamellae are present at least in the early radial growth stage. Similar characters occur in multistriata. Valves dredged in 300-420 m, mainly off Transkei, are doubtlessly derived from a Pleistocene regression; they tend to be slightly atypical in their more prominent commarginal lamellae in the early radial stage, and their smaller radial riblets.» DIJKSTRA, H. H. & R. N. KILBURN. 2001. The family Pectinidae in South Africa and Mozambique (Mollusca: Bivalvia: Pectinoidea). African Invertebrates, 42: 263-321. [p. 302]
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Talochlamys multistriata (Poli, 1795); H. H. Dijkstra & R. N. Kilburn, 2001, The family Pectinidae in South Africa and Mozambique, figures 38, 39.
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«Types.— Poli's (1795) work on the living bivalves of Sicily was based largely on his own extensive shell collection (Dance, 1966: 95; Kohn, 1988: 39), which apparently has not been preserved. Previous authors who have discussed the taxonomy of this well-known species in detail, e.g. Bucquoy et al. (1887: 104), Sacco (1897: 6), and Roger (1939: 165), have not mentioned type specimens, possibly because Poli provided an illustration the identity of which has never been questioned. Following the International Code of Zoological Nomenclature [Art. 74(b)] and the example of Kohn (1988: 39), the specimen represented by the figure in Poli (1795, Pl. 28, Fig. 14) is herein selected as the lectotype.
The types of the three species of Reeve (1 853) listed in the synonymy were examined at The Natural History Museum, London. All are represented by syntype series. In the interest of nomenclatural stability, lectotype designations are as follows: Pecten tinctus Reeve, syntypes, two complete shells and a single right valve. The specimen of height 32.5 mm, length 27.5 mm, and convexity of the complete shell 13.0 mm, BMNH 1981247/1 is herein selected as the lectotype (Figs. 6e,f), because it is apparently the specimen that Reeve figured. The paralectotypes are BMNH 1981247/2-3. Pecten effulgens Reeve, syntypes, two complete shells. The darker of the two, BMNH 1993039/1, height 18.8 mm, length 15.0 mm, is represented in Reeve's figure 156 and is herein selected as the lectotype (Figs. 6g,h). This taxon was recently incorrectly placed in the synonymy of P. cruentatus Reeve, 1853, by Rombouts (1991: 27). Reeve's P. cruentatus is a Mimachlamys that is closely related to and possibly a junior synonym of the Indo-Pacific Mimachlamys senatoria (Gmelin, 1791). Pecten textilis Reeve, syntypes, a single right valve (Fig. 6j) and single left valve (Fig. 6i). The left valve, BMNH 1993040/1, height 24.9 mm, length 20.2 mm, is represented in Reeve's fig. 174 and is selected herein as the lectotype. Type locality.— Sicily.
Diagnosis.— Byssate, non-cemented Crassadoma of small size (less than 40 mm in height); ribs introduced continuously throughout ontogeny without distinct clustering or ordering; 70 to 80 continuously scaly ribs and riblets present at distal margin of mature shells; inner surface of shell inside pallial line lacking foliated calcite throughout ontogeny.
Morphological variation.— The only significant geographic variation in Crassadoma multistriata occurs along the Atlantic and Indian Ocean coasts of southern Africa, where specimens tend to have narrower umbonal angles (as narrow as 80º) and correspondingly higher height to length ratios (as high as 1.34). Some authors have considered these narrow forms to be a distinct species, Chlamys tincta (Reeve, 1853) (Figs. 6e, f). The two forms, however, overlap in shell narrowness and are identical in details of ribbing and microsculpture.
Some authors have thought that Crassadoma multistriata becomes cemented in the northern part of its range along the Atlantic coast of France and have therefore treated this species and C. pusio as synonyms (see following discussion). On the basis of the evidence on hand, however, I have not been able to substantiate intergradation of these taxa. Bucquoy et al. (1887: 104) noted the presence of both regular and distorted forms in single samples from Brest, France, but illustrated a regular specimen that was still within the size range of the pre-cementation stage of C. pusio. Shell distortion in the absence of cementation is not a diagnostic feature, because it occurs in many independent lineages of byssate, nestling chlamydoid pectinids. In C. multistriata, distortion is common among many specimens in the Atlantic, including specimens at both the northern and southern limits of its geographic range. Pre-cemented C. pusio, however, can generally be distinguished from C. multistriata in the same size range using criteria summarized below. Comparison.— Crassadoma multistriata (Figs. 6a-j) closely resembles its western Atlantic counterpart, Caribachlamys sentis (Figs. 6m-p), in shell shape, color, and the
lack of a foliated-calcite transgression on the inner shell surface in the umbonal region. The former, however, has a normal prodissoconch (Fig. 5a), whereas that of the latter has a prodissoconch dominated by the PI stage (Figs. 7a,g). The umbonal region of the disk of C. multistriata is more inflated and less flattened than that of C. sentis, and the byssal fasciole of C. multistriata generally has a deeply incised groove whereas that of C. sentis does not. Crassadoma multistriata differs from C. pusio (Figs. 6k,l) in lacking cementation and foliated-calcite umbonal transgressions throughout ontogeny. In C. pusio cementation and attendant changes in morphology begin at shell heights between about 12 and 25 mm. The pre-cementation growth stage of C. pusio closely resembles shells of C. multistriata of similar size. Even at this early stage, however, the two species can be distinguished by two features. First, in C. multistriata, there is no transgression of foliated calcite from the hinge region ventralward across the region inside the pallial line at any stage of growth. In C. pusio, foliated calcite generally begins to form on the inner shell surface at the dorsal edge of the umbonal region at a shell height of about 17 mm in right valves and about 13 mm in left valves, generally before cementation begins. In mature shells over most of the geographic range of C. pusio, this foliated calcite may extend ventrally at least to the level of the top of the adductor scar. Secondly, the beak of the left valve of C. multistriata has only weak microsculpture, particularly near the distal margin of the preradial stage (Fig. 5d); microsculpture at this same stage is stronger in C. pusio, consisting of distinct, generally discontinuous antimarginal striae and pits (Fig. 5e). Crassadoma multistriata also resembles C. harmeri (Regteren Altena, 1937) of the Plio-Pleistocene of western Europe and Great Britain. The fossil species differs in reaching a larger size (commonly exceeding a height of 70 mm), in having a minor foliated-calcite transgression on the inner shell surface in the umbonal region of each valve, and in having a distinct anterior-posterior trending ridge on the inner surface of its right anterior auricle. Living habits.— Crassadoma multistriata lives byssally attached to hard objects on the substrate at shallow shelf depths from below low tide level to at least 100 m in normal marine environments. Dead shells, particularly of juveniles, have been dredged from depths as great as 700 m. The species is apparently eurythermal and possibly has been ecologically generalized throughout much of its history. Blondel and Demarcq (1990: 250), in a study of the Early and Middle Miocene (late Burdigalian to early Langhian) fossil record of northern Tunisia, refer to the species as eurytopic.
Geographic range.— Crassadoma multistriata has an enormous latitudinal range, occurring from the Brittany coast of France southward into the Mediterranean and thence southward along the African coast to southernmost South Africa (Nicklbs, 1955). The species occurs throughout the Mediterranean as well as in the Madeira, Canary, and Cape Verde Islands. It is also present in the central South Atlantic at St. Helena (USNM 124060 and 764331). Along the southern and southeastern coasts of Africa, C. multistriata is abundantly represented in USNM collections from False Bay, South Africa, to southern Mozambique (USNM 764201 and 764219) in the Indian Ocean.
Stratigraphic range.— Lower Miocene to present.
Sacco (1897: 9) showed the stratigraphic range of "Chlamys" multistriata as extending as far down as the Tortonian (Upper Miocene) and that of its lineage antecedent, "Chlamys" tauroperstriata Sacco, 1897, sensu stricto, as extending as far down as the lowermost Miocene (Aquitanian). Cox (1927: 42-43) thought that "Chlamys" pusio (which he used as a senior synonym of Chlamys multistriata) was "well established in Lower Miocene times" and was present in the Miocene of Persia. Roger (1937: 167) noted that "Chlamys" multistriata is common in the Lower Miocene (Burdigalian) in the Mediterranean region from the Rône Valley to the Vienna Basin. It is generally thought that the species has a Mediterranean origin (Lauriat-Rage, 1981: 43). The stratigraphic history of the species in the eastern Atlantic outside of the Mediterranean, however, is not precisely known."» WALLER, T. R. 1993. The evolution of Chlamys (Mollusca: Bivalvia: Pectinidae) in the tropical western Atlantic and eastern Pacific. American Malacological Bulletin, 10 (2): 195-249. [p. 212-214]
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Crassadoma multistriata (Poli, 1795); T. R. Waller, 1993, The evolution of Chlamys, figures 5a,d,g (above); figures 6c-j (below).
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