Pseudopecten veyrasensis (Dumortier, 1864)
DUMORTIER, E. 1864. Études
Paléontologiques sur les Dépots Jurassiques du Bassin du Rhone. Première
Partie. Infra-Lias. F. Savy, Éditeur. Paris. 1-187 p., pls. 1-30. [p. 163, pl. 24, fig. 15]
1855 Pecten aequiplicatus Terquem, 1855
1864 Pecten veyrasensis Dumortier, 1864
1869 Pecten julianus Dumortier, 1869
1869 Pecten humberti Dumortier, 1869
1878 Pecten heterotus Gemmellaro & Di Blasi in Gemmellaro, 1878
1878 Pecten isoplocus Gemmellaro & Di Blasi in Gemmellaro, 1878
1886 Pecten seguenzae Di Stefano, 1886
1864 Pecten veyrasensis Dumortier, 1864
1869 Pecten julianus Dumortier, 1869
1869 Pecten humberti Dumortier, 1869
1878 Pecten heterotus Gemmellaro & Di Blasi in Gemmellaro, 1878
1878 Pecten isoplocus Gemmellaro & Di Blasi in Gemmellaro, 1878
1886 Pecten seguenzae Di Stefano, 1886
E. Dumortier, 1864, plate 24.
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«Testa orbiculari, compressa, costata, costis circa 13 angulatis, latis, rugis transversis impressis, quae in medio costarum angulosae sursum ascendunt, intervallis profunde impressis, foraminatis.
Dimensions: longueur 20 millim., largeur 20 millim., épaisseur 5 millim. ½, ouverture de l'angle apicial 93°. Coquille arrondie, épaisse, portant environ 13 côtes, grosses, carénées, ornées de rides saillantes, en chevrons, dont le sommet est dirigé en haut. Les sillons qui séparent les côtes sont étroits et profonds, et comme les chevrons qui ornent ces côtes viennent s'y rencontrer, il en résulte que ces sillons ne sont qu'une série de petites cavités resserrées entre les extrémités de ces chevrons. Entre la dernière côte et le bord de la coquille il existe une petite aréa, ornée de stries transverses. Le bord cardinal est droit. — L'oreille antérieure grande, ornée de stries verticales sinueuses et fortement échancrée pour le passage du byssus: oreille postérieure...... La coquille est fortement sinueuse dans la région palléale. Ce Pecten est précieux, parce que, grâce à sa livrée riche et compliquée, il est toujours reconnaissable, même dans ses fragments. Il paraît spécial aux dépôts de l'Ardèche: je l'ai recueilli à Veyras, dans les couches remplies de tiges du Neuropora socialis, si remarquables de cette localité. Localité: Veyras. r. Explication des figures: Pl. XXIV, fig. 15, Pecten Veyrasensis, de Veyras, grossi deux fois. De ma collection.» EUGÈNE DUMORTIER, 1864
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«2. AMENDED DIAGNOSIS
Distinguished from Ps. (Ps.) dentatus and Ps. (Ps.) equivalvis by the lower modal number of plicae (14 cf. 17/18 and 22 respectively) and from the latter also by the vertically striated disc flanks and down-sulcal tongueing of the comarginal striae.
3. AMENDED DESCRIPTION
Essentially similar to Ps. (Ps.) dentatus, differing only by the diagnostic feature (see Section 2), the ränge of plical variation (12-15, text fig. 62) and by the tendency to develop a rectilinear plical form on the shell interior (Pl. 2, Fig. 21). The maximum height is 74.5 mm (GPIG).
4. DISCUSSION
The specific name applicable to the range of forms making up the left-hand peak of text fig. 62 is a matter of some uncercainty. Apparently, the earliest description of a species within the 12-15 plicae ränge is 'Pecten' aequiplicatus TERQUEM. Although the text specifies the relatively uncommon number of 12 plicae the figure illustrates a more typical specimen with 15 plicae. However, TERQUEM also referred to small spines on the left valve and subsequent applications of the name, by authors who may have had access to the type material, have been to forms with 12 plicae and spines (DECHASEAUX, 1936) or 10 plicae (LENTINI, 1973) which suggest that 'P. ' aequiplicatus is a poorly figured junior synonym of Spondylopecten (Plesiopecten) subspinosus. In contrast, COSMANN (1904) has figured a specimen with 16 plicae under TERQUEM's species which suggests that 'P.' aequiplicatus is an extreme variant of Ps. (Ps.) dentatus. In view of this ambiguous usage and in the lack of knowledge concerning the whereabouts of the type material, it seems best to rule out TERQUEM's species as a candidate for the name of the species described in Section 3. The next available name is 'P. ' Veyrasensis DUMORTIER. The original description (see Section 1) specifies 13 plicae although the figure shows a more typical number of 14. DUMORTIER's species 'P.' Julianus and 'P.' Humberti, with 12 and 14 plicae respectively, fall within the ränge of variation and exhibit no other distinguishing features.»
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. 78]
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Pseudopecten (Pseudopecten) veyrasensis (Dumortier 1864); A. L. A. Johnson, 1984, The palaeobiology of the bivalve families Pectinidae and Propeamussiidae in the Jurassic of Europe, plate 2, figures 19-21.
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