Lyriochlamys septemplicata (Nilsson, 1827)
NILSSON,
S. 1827. Petrificata suecana formationis cretaceae, descripta et iconibus
illustrata a S. Nilsson. Pars prior, vertebrata et mollusca sistens, viii, 37 p., pls. 1-10.
Londini Gothrum, Ex Officina Berlingiana. [p. 20, pl. 10, fig. 8 a, b]
1827 Pecten septemplicatus Nilsson, 1827
1833 Pecten ptychodes Goldfuss, 1833
1922 Pecten brandesi J. Böhm, 1922
1922 Pecten infractus J. Böhm, 1922
1833 Pecten ptychodes Goldfuss, 1833
1922 Pecten brandesi J. Böhm, 1922
1922 Pecten infractus J. Böhm, 1922
S. Nilsson, 1827, plate 10.
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«P. testa ovato-rotundata, subobliqua, radiatim plicata; plicis septem convexis & interstitiis longitudinaliter striatis; striis squamiferis; squamis fornicatis; auriculis inaequalibuus striatis. Long. 1¼ -2 poll. (Tab. nostr. X. fig. 8. A. B. mediocres).
Descript. Haec pulchra species, quam nullibi descriptam invenimus, dignoscitur testa ovato-rotundata, obliqua, inaequivalvi; valva altera magis, altera minus convexa; utraque radiatim plicata; plicae septem convexae, quas inter totidem concavae. Accretionis stationes duae vel tres distinctissimae sunt, & valva convexior ad illas quasi infracta. Tota testa ornatur lamellis tenuibus transversis undatis, quae tamen in speciminibus plurimis evanuerunt. In omnibus vero cernuntur striae longitudinales squamulis formicalis ornatae, quarum tres pleruinque series in unaquaque plica, & tres in interstio observantur. Hae quoque squamulae haud raro oblitteratae sunt; sed in interstitiis concavis lenticulo examinatis, vestigia earum plerumque deteguntur. Auriculae inaequales & transversim striatae. lntus inspecta testa quoque septemplicata, plicis radiantibus laevibus, margine subangulatis. Hac quoque nota dignoscitur facillime a praecedente specie cujus valva convexa intus ornatur sulcis numerosissimis. Locus: In parte septentrionali litoris Kjugestrand cum praecedente. Ad Balsberg in petra conchacea; atque in petra arenacea e regione lacus Yngsjö dicti, cum Ostrea Iunata &c. reperitur.» SVEN NILSSON, 1827
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«The name Lyriochlamys (type species, Pecten fissicosta Etheridge, 1881) was introduced by Sobetski (1977) as a subgenus of Chlamys for the purpose of accommodating species with complex ribbing patterns. Extremes of these patterns, such as in Lyriochlamys septemplicata (Nilsson, 1827), have a low number of major plicae overlain by fine radial costellae. The type species chosen by Sobetski (1977), however, does not show this extreme condition, and there seems to be a transition in ribbing complexity among species of Mesozoic "Chlamys" just as there is among Cenozoic and Holocene species.»
WALLER, T. R. & L. MARINCOVICH JR. 1992. New species of Camptochlamys and Chlamys (Mollusca: Bivalvia: Pectinidae) from near the Cretaceous/Tertiary boundary at Ocean Point, North Slope, Alaska. Journal of Paleontology, 66 (2): 215-227. [p. 223]
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Chlamys (Lyriochlamys) septemplicata (Nilsson, 1827); V. A. Sobetski, 1977, Late Cretaceous bivalve molluscs of the platform seas of southwestern USSR, plate 4, figure 3.
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«Discussion: I would like to add the following to what I wrote in 1972: the rib ornamentation varies according to the preservation state (or the growth stage on some specimens): from almost smooth near the umbo, the ribs, especially near the pallial margin, become often strongly subdivided into riblets. This applies equally to the intercostal intervals. This can clearly be seen on a specimen from near Lérida (Spain) figured in 1984 (p. 864, pl. 1, fig. 6) and on an incomplete specimen from the Hochmoos Fm.
Merklinia septemplicata has an interesting distribution: from Santonian to Maastrichtian beds it has been found in shallow (relatively warm) temperate European and Northern Tethyan exposures. The related species M. catalaunica (VIDAL) (= M. perornata [COTTREAU]) has been found in more southern Tethyan exposures at about the same stratigraphie levels. Only in Northern Spain are both species found in the same region. Occurrence and distribution: Santonian of Austria and Denmark, Campanian of Germany (Harz), and Sweden, Campanian - Maastrichtian of Belgium - the Netherlands, Bulgaria, S.W. France, Spain.» DHONDT, A. V. 1987. Bivalves from the Hochmoos Formation (Gosau-Group, Oberösterreich, Austria). Annalen der Naturhistorischen Museums in Wien, 88: 41-101. [p. 68]
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«Merklinia septemplicata (NILSSON, 1827): originally described from the Campanian of Sweden; fig. in Dhondt (1972 b, pl. 3, fig. 3 sub Lyropecten septemplicatus); widely distributed but rarely occurring from the Santonian to Late Maastrichtian: Sweden, Germany, Belgium-the Netherlands, Austria, Bulgaria.
Occurrence in Spain: Campanian: Lérida: Coil d’Ares, Montsec Section (I. Br.), Maastrichtian: Lérida: Serie V Homes Morts (Univ. Bell. coll. 3. Gallemi).» DHONDT, A. V. 1982. Some Spanish Cretaceous bivalves. Cuadernos de Geología Ibérica, 8: 847-865, pl. 1. [p. 851]
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Merklinia septemplicata (Nilsson); A. V. Dhondt, 1982, Some Spanish Cretaceous
bivalves, plate 1, figure 6.
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«The type specimen has not been very well figured by NILSSON: the measurements are U. P. D.44.9 mm, W. 41.85 mm, A. A. 86°, R number 7.
The shape is rather convex and prosocline with two concentric pronounced growth ridges and an abrupt steep transition between the second growth ridge and the pallial margin; the ribs are covered with small unevenly distributed spines. The differences between Pecten ptychodes GOLDFUSS and P. septemplicatus are probably only due to variability: the size, number of ribs and general shape are identical but the spines as drawn by GOLDFUSS seem to be far more numerous and mostly located in the intercostal intervals, whereas on NILSSON's type specimen and on all the other specimens they are limited to the ribs. It could be that GOLDFUSS (fig. 4b) does not give a good idea of the specimen since the description states explicitly that both ribs and intervals carry riblets with spines. The very convex form described by ZITTEL, for specimens from the Gosau is found on one specimen from Maastricht type area, and the type specimen also has it. This explains why it is unnecessary to consider the Gosau specimens as belonging to another species as did J. BOEHM, 1922 (Pecten infractus). L? septemplicatus differs from : — L. (A?) ternatus in having undivided rounded ribs. — L. (A?) trigeminatus in having fewer, undivided, rounded ribs and shallow intercostal intervals. The differentiation towards the other L. (A?) species on the same grounds as those indicated for differentiating those species from L. (A?) ternatus. Generic attribution: The elongated, prosocline shape and the low ribnumber make it difficult to decide whether Pecten septemplicatus NILSSON, 1827 does really belong into Lyropecten. Tentatively, because of its morphological similarity with L. (A?) ternatus and L. (A?) trigeminatus it is attributed to Lyropecten. Hence Lyropecten ? septemplicatus (NlLSSON, L827).» DHONDT, A. V. 1972b. Systematic revision of the Chlamydinae (Pectinidae, Bivalvia, Mollusca) of the European Cretaceous. Part 2: Lyropecten. Bulletin de l’Institut Royal des Sciences Naturelles de Belgique 48 (7): 1-81, pls. 1-3. [p. 63, 64]
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Lyropecten? septemplicatus (Nilsson, 1827); A. V. Dhondt, 1972, Systematic revision of the Chlamydinae of the European Cretaceous. Part 2: Lyropecten, plate 3, figure 3.
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«Die flachgewölbte, mit sieben kräftigen, gerundeten Rippen versehene, beinahe kreisförmige Schale ist bei Ilsede ziemlich häufig, kommt jedoch meistens ohne Ohren vor. Rippen und Zwischenräume sind gleich gross und werden von abwechselnd stärkeren und feineren Radialstreifen bedeckt. Die Anwachsstreifen rufen namentlich in den weniger abgeriebenen Zwischenräumen eine blättrig-schuppige , dachziegelartige Sculptur hervor.
Original in der Sammlung der Geologischen Landesanstalt.» MÜLLER, G. 1898. Die Molluskenfauna des Üntersenon von Braunschweig und Ilsede. I. Lamellibranchiaten und Glossophoren. Abhandlungen der Königlich Preussischen geologischen Landesanstalt [Neue Folge], 25: 1-142, pls. 1-18. [p. 32]
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Pecten septemplicatus Nilss.; G. Müller, 1898, Die Molluskenfauna des Üntersenon von Braunschweig und Ilsede, plate 5, figures 2a, 2b.
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