Plesiopecten subspinosus (Schlotheim, 1820)
SCHLOTHEIM, E. F. VON. 1820. Die Petrefactenkunde auf ihrem jetzigen Standpunkte durch die Beschreibung seiner Sammlung versteinerter und fossiler Überreste des Thier- und Pflanzenreichs der Vorwelt erläutert. lxii, 437 p. Becker'schen Buchhandlung. Gotha, 1820. [p. 223]
1820 Pectinites subspinosus Schlotheim, 1820
1833 Pecten novemplicatus Münster in Goldfuss, 1833
1850 Pecten orontes Orbigny, 1850
1850 Pecten hedonia Orbigny, 1850
1850 Lima bellula Orbigny, 1850
1857 Pecten bouchardi Oppel, 1857
1862 Pecten sarmerensis Étallon in Thurmann & Étallon, 1862
1878 Pecten oromedon Loriol, 1878
1912 Chlamys (Aequipecten) bouillerieri Cossmann, 1912
1923 Plesiopecten fusciaensis Lissajous, 1923
1833 Pecten novemplicatus Münster in Goldfuss, 1833
1850 Pecten orontes Orbigny, 1850
1850 Pecten hedonia Orbigny, 1850
1850 Lima bellula Orbigny, 1850
1857 Pecten bouchardi Oppel, 1857
1862 Pecten sarmerensis Étallon in Thurmann & Étallon, 1862
1878 Pecten oromedon Loriol, 1878
1912 Chlamys (Aequipecten) bouillerieri Cossmann, 1912
1923 Plesiopecten fusciaensis Lissajous, 1923
Pecten subspinosus Schlotheim; A. Goldfuss,1833-1840, Petrefacta Germaniae, pIate 100, figures 4a-4c.
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«Mehrere Exemplare in Hornstein, gleichfalls von Amberg (12 Ex.).
In der Form dem vorhergehenden ziemlich ähnlich nur viel kleiner, und höchstens nur einen Zoll im Durchmesser erreichend, mit verhältnismäßig ziemlich breiten, mit gekörnten Querstrichen versehenen Ohren. Von flacherer Wölbung als der vorhergehende. Beyde Hälften gleichförmig gewölbt, die Rippen stark hervorspringend, spitzwinklich zulaufend, und mit kleinen Dornen besetzt. Die sehr feinen eng zusammen stehenden erhabenen Querrippen sind nur in den Zwischenfurchen sichtbar, und veranlassen, daß man Einkerbungen oder vertiefte Punkte in den Zwischenfurchen wahrzunehmen glaubt. Ein darunter befindliches zum Theil verkieseltes Exemplar ist unter den Hornsteinversteinerungen merkwürdig. Er scheint in der dortigen Gegend ziemlich häufig zum Vorschein zu kommen.»
ERNST FRIEDRICH VON SCHLOTHEIM, 1820
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«Description. Equivalve, equilateral, moderately inflated shell. Specimens preserved either as internal moulds or with abraded shell, which carries 20 to 25 radial ribs. In rare cases, these ribs exhibit an angular cross-section, and carry a faint line at their crest. Anterior auricles larger than posterior ones, well demarcated from disc. Right anterior auricle carrying several radial riblets crossed by numerous commarginal lamellae.
Remarks. The angular ribs place the specimens firmly into Spondylopecten (Plesiopecten) subspinosus as defined by Johnson (1984).» FÜRSICH, F. T. & Y. PAN. 2014. Callovian-Oxfordian (Jurassic) bivalves from the Kamar-e-Mehdi Formation of east-central Iran. Beringeria, 44: 3-50, pls. 1-16, text figs. 1-3. [p. 34]
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Spondylopecten (Plesiopecten) subspinosus (Schlotheim, 1820); F. T. Fürsich & Y. Pan, 2014, Callovian-Oxfordian (Jurassic) bivalves from the Kamar-e-Mehdi Formation of east-central Iran, plate 11, figures 1-5.
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«The 12 syntypes originally described by Schlotheim(1820) as 'Pectinites' subspinosus were subsequently added to such that the Schlotheim collection (HM) now contains 18 specimens under this specific name (Dr. J. HELMS, pers. comm., 1978). The specimens are variably preserved and it is not certain which constitute the syntypes. However, all appear to be referable to the species described in Section 3 and this fact together with the unambiguousness of the description (see Section 1) can leave little doubt as to SCHLOTHEIM's hypodigm. Accordingly one of the 18 specimens (HM MB-M. 25.4; PI. 3, Fig. 1) is herein designed as lectotype and a further 6 specimens (HM MB-M. 25.1-3, 5-7) are selected as paralectotypes.
The single observed type ot 'Lima' Bellula D'ORBIGNY (MNO 3737) and the sole observed type of 'P.' Hedonia D'ORBIGNY (MNO 2421) with 12 and 13 plicae respectively, together with the two syntypes of 'P.' Orontes D'ORBIGNY (MNO 3766) with 11 and 13 plicae, all fall within the range of plical variation in S. (PI.) subspinosus and can be distinguished on no other count. Similarly, 'P.' lykosensis KRUMBECK and 'Chlamys' ('Aequipecten') Bouillerieri COSSMANN, both with 11 plicae, cannot be accorded a specific distinction. Although the figure of 'P.' aequiplicatus TERQUEM shows 15 plicae and is similar to Pseudopecten (Ps.) veyrasensis the text specifies 12 plicae and spinose ornament as is characteristic of S. (PI.) subspinosus. Some subsequent applications of TERQUEM's specific name by authors who may have examined the type material appear tobear out the latter assignation (e. g. LENTINI [1973] for forms with 10 plicae and DECHASEAUX [1936] for forms with 12 plicae and spines). However, COSSMANN's (1904) usage is for a form with 16 plicae which is probably referable to Ps. (Ps.) dentatus and it is thus conceivable that 'P. ' aequiplicatus TERQUEM could represent the extremes of variation in the latter species. Unfortunately discussion of the taxonomic position of 'P. ' aequiplicatus is hampered by the fact that the presence or absence of the cardinal crura diagnostic of Spondylopecten has yet to be demonstrated in either the specimens cited in the bibliographic references above or in museum specimens from comparable horizons (Lias) examined by the author (however see Section 5). For the same reason the taxonomic position of 'P. ' novemplicatus MÜNSTER (a species founded on a fragmentary specimen from the Lias which must have onginally possessed about 12 plicae) is also uncertain. 'P. ' Bouchardi OPPEL was originallv erected for forms differing from typical S. (Pl.) subspinosus only by their greater convexity and stronger plicae. STAESCHE (1926), in maintaining a specific distinction, added that such forms were also characterised by wider sulci lacking in comarginal ornament but failed to recognise that all four features are correlates of relatively large size, as is clearly illustrated by his figured specimen (H: 20.9). 'Pl.' fusciacensis LISSAJOUS, erected for large specimens (Hmax: 27) lacking comarginal ornament in the sulci, is similarly inseparable from S. (Pl.) subspinosus and since the development of intercalary plicae appears to be another correlate of large size (YIN, 1931), 'P. ' Sarmerensis ÉTALLON cannot be accorded a specific distinction on this basis. 'P. ' Oromedon in LORIOL only differs from S. (PI.) subspinosus by its more rounded plicae. This is almost certainly the result of abrasion. 'P. ' lottii GEMMELLARO and DI BLASI was erected for a single specimen from the L. Lias resembling S. (Pl.) subspinosus in its convexity and Ps. (Ps.) veyrasensis in its number of plicae (15). STAESCHE (1926) has suggested that it may represent a transitional form between the two species (but see Section 10).» JOHNSON, A. L. A. 1984. The palaeobiology of the bivalve families Pectinidae and Propeamussiidae in the Jurassic of Europe. Zitteliana, 11: 1-235, pls. 1-11. [p. 86]
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Spondylopecten (Plesiopecten) subspinosus (Schlotheim, 1820); A. L. A. Johnson, 1984, The palaeobiology of the bivalve families Pectinidae and Propeamussiidae in the Jurassic of Europe, plate 3, figures 1-5, 6?, 7?
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