Camptonectes virgatus (Nilsson, 1827)
NILSSON, S. 1827. Petrificata suecana formationis cretaceae, descripta et iconibus illustrata a S. Nilsson. Pars prior, vertebrata et mollusca sistens. Londini Gothrum, Ex Officina Berlingiana. viii, 37 p., pls. 1-10. [p. 22, pl. 9, fig. 15]
1820 Pectinites excentricus Schlotheim, 1820 [nomen oblitum]
1827 Pecten virgatus Nilsson, 1827
1842 Pecten jugleri Hahenow, 1842
1843 Pecten curvatus Geintz, 1843
1846 Pecten divaricatus Reuss, 1846
1850 Pecten besseri Alth, 1850
1869 Pecten althi Fabre, 1869 [nomen novum pro Pecten besseri Alth, 1850]
1882 Pecten dichotomus Seguenza, 1882
1889 Pecten fulminifer Holzapfel, 1889
1906 Pecten (Camptonectes) kalkowskyi Petrascheck, 1906
1934 Pecten hierichuntinus Blanckenhorn, 1934
1940 Pecten woodsi Tavani, 1940
1977 Camptonectes perlucidus Sobetski, 1977
1827 Pecten virgatus Nilsson, 1827
1842 Pecten jugleri Hahenow, 1842
1843 Pecten curvatus Geintz, 1843
1846 Pecten divaricatus Reuss, 1846
1850 Pecten besseri Alth, 1850
1869 Pecten althi Fabre, 1869 [nomen novum pro Pecten besseri Alth, 1850]
1882 Pecten dichotomus Seguenza, 1882
1889 Pecten fulminifer Holzapfel, 1889
1906 Pecten (Camptonectes) kalkowskyi Petrascheck, 1906
1934 Pecten hierichuntinus Blanckenhorn, 1934
1940 Pecten woodsi Tavani, 1940
1977 Camptonectes perlucidus Sobetski, 1977
S. Nilsson, 1827, plate 9.
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«P. testa suborbiculari, striata; striis mediid ramosis per per dichotomiam sensim divisis, lateralibus divergentibus arcuatis; auriculis inaequalibus reticulato striatis. Diam. 12-18 mm. (Tab. nostra IX. fig. 15.)
Parvulus hic Pectinites inter pulcherrimos est eorum qui in formatione cretacea obveniunt. Quoad formam & magnitudinem similis est Pectini pulchello; costulae parvae frequentissimae subrugosae, in media testa longitudinales, ramosae, per dichotomiam sensim multiplicatae; juxta latera vero magis arcuatae. Auriculae inaequales, reticulatim striatae; margine rostri aItero recto, altero concavo. Locus: Obvenit ad Balsberg & Mörby; sed inter rariores esse videtur.» SVEN NILSSON, 1827
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«v* 1827 Pecten virgatus Nilsson: 22, pl. 9, fig. 15.
v. 1972a Camptonectes (Camptonectes) virgatus (S. Nilsson); Dhondt: 18, pl. 2, fig. 1. (cum syn.) v. 1977 Camptonectes virgatus (Nilsson); Sobetski: 65, pl. 4, fig. 16. v. 1977 Camptonectes perlucidus Sobetski: 66, pl. 4,fig.17. · 1981 Camptonectes (Camptonectes) virgatus (Nilsson); Tzankov: 101, pl. 45, fig. 1. v. 1982 Camptonectes virgatus (Nilsson); Dhondt: 81. v? 1982 Camptonectes curvatus (Geinitz); Sobetski: 113, pl. 11, fig. 19. · 1985 Camptonectes (Camptonectes) virgatus (Nils.); Freneix and Viaud: 203, pl. 1, fig. 10. · 1986 Camptonectes (Camptonectes) virgatus (Nilsson); Abdel-Gawad: 151, pl. 32, fig. 16. v. 1987 Camptonectes virgatus (Nilsson); Dhondt: 67, pl. 3, fig. 3. Material. A single external cast, fram Drain Vequée.
Dimensions. UPD 11.5 mm, W 9.8 mm.
Remarks. The typical diverging ornamentation is beautifully preserved on this specimen.
Distribution. From Cenomanian to latest Maastrichtian, virtually world-wide, but generally more common in coarser than in finer sediments, also found in the Maastrichtian stratotypical area.»
DHONDT, A. V. & J. W. M. JAGT. 1996. Late Creatceous macrofauna from the Hautes Fagnes area (NE Belgium). Annales de la Societé géologique de Belgique, 119 (1): 39-53, pls. 1, 2. [p. 44]
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Camptonectes vlrgatus (Nilsson, 1827); A. V. Dhondt & J. M. W. Jagt, 1996, Late Creatceous macrofauna from the Hautes Fagnes area (NE Belgium), plate 2, figure 1.
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«Material: One incomplete right valve (E88: L = 34 mm) from Pinei, Lago di S. Croce.
Discusion: The typical diverging camptonectid striae are clearly visible on the specimen, but the punctae are more difficult to recognize. As in the Gosau (Dhondt, 1987), the specimen from the Lago di S. Croce area is large for the species and the divergent and punctate striation (camptonectid ornamentation) is of the "fine" type, such as also found on African specimens (Dartevelle and Freneix, 1957).
Distribution: Generally more common in coarse deposits, and only rarely found in chalks. It occurs from Cenomanian to Maastrichtian and has a world-wide distribution, but has not previously been described from the latest Coniacian-earliest Campanian rudist formations of the eastern Venetian Prealps (Text-fig. 2).»
DHONDT, A. V. & I. DIENI. 1993. Non-rudistid bivalves from Late Cretaceous rudist limestones of NE Italy (Col di Schiosi and Lago di S. Croce areas). Memorie di Scienze Geologiche, 43: 165-241, pls. 1-20, text-figs. 1-18. [p. 188]
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Camptonectes virgatus (Nilsson, 1827); A. Dhondt & I. Dieni, 1993, Non-rudistid bivalves from Late Cretaceous rudist limestones of NE Italy (Col di Schiosi and Lago di S. Croce areas), plate 4, figure 12.
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«Description
Diagnosis. — Small to medium-sized Camptonectes species with orbicular, rather convex, acline valves with very unequal auricles. Sculpture: consists of dichotomous radial striae which diverge from the umbo towards the pallial and side margins; they diverge from the middle of the disc more or less along the U. P. D.. The diverging striae are traversed by concentric growthlines. The complete shell surface is divided into small rectangles. At the intersection-points between concentric and diverging striae lie the Camptonectes-punctae. The number of striae, both concentric and radial is extremely variable. The sculpture is the same on both valves. Right valve: anterior auricle: winglike and elongated; the sculpture is the same as on the disc, but the radial striae are straight and almost parallel to the hinge margin; the concentric striae start at the margin, curve and follow the byssal sinus; the same sculpture is found on all the auricles, but it is not as clearly visible on the others. Posterior auricle: smaller, and obtuse at its outer angle. Left valve: anterior auricle; almost rectangular at its outer angle; Posterior auricle: smaller and obtuse at its outer angle. Discussion
Variability:
The variability in size is very wide but, not equally so in all strata: in the Hervian (Campanian) near Aachen the largest specimens reach a U. P. D. of more than 35 mm but in Maastricht the largest specimens are only 25 mm high. Large specimens are also known from the Cenomanian Czech strata, but the Cenomanian French strata yield only small specimens. Synonymy: In the museum of the von Humboldt University of Berlin I saw the specimen labelled «Original von Schlotheim, Pecten excentricus, Petrefactenkunde». It comes from Aachen; HENNIG, 1897 stated that it is a Pecten virgatus NILSSON. In the Staatliches Museum in Dresden I saw the holotype of Pecten curvatus GEINITZ: GEINITZ's figure (pI. 3, fig. 13) is not like the typespecimen which is a «Steinkern» and which has little of the original sculpture left; as far as can be seen it is a Camptonectes virgatus. The type-specimens of Pecten jugleri are lost. In the collections of the University of Greifswald many specimens from Rügen make an objective opinion possible of that taxon: all specimens from Rügen have auricles with a normal C. virgatus shape and sculpture. On most specimens, however, the discs seem smooth. On a few specimens the C. virgatus-ornamentation is visible near the side margin too. It seems that the Rügen specimens are typical C. virgatus specimens but that the discs are worn off, and the ornamentation only remains visible where it has always been more clearly visible, namely on the auricles and on the areas. The original of Pecten fulminifer HOLZAPFEL is probably lost in the partial destruction of the «Preussische Geologische Landesanstalt» in Berlin during the Second World War. In the Museum d'Histoire naturelle in Paris there is one specimen from the Hervian in Vaals (ColI. DE VIBRAYE): it bears the elevated structures which HOLZAPFEL considered to be specific for P. fulminifer. On checking this specimen carefully I noticed that the elevated structure is the result of the silicification which took place after the fossilisation. The elevated parts can be very easily removed without damaging the fossil and what is left is a normal C. virgatus. HOLZAPFEL pointed out that in C. virgatus the range of variability in size and sculpture is very wide. I came to the same conclusion; hence, I consider that Pecten (Camptonectes) kalkowskyi PETRASCHECK is a large C. virgatus; some C. virgatus specimens from Aachen almost reach the size given for C. kalkowskyi by PETRASCHECK. The specimens described by LEHNER as Pecten (Camptonectes) virgatus var. occultestriatus (in the Bayerische Staatsammlung in Munich) are real C. virgatus by their shape and sculpture. Pecten divaricatus REUSS and Pecten besseri ALTH (non ANDREZEJOWSKI) (= P. althi FAVRE) are within the variability range of C. virgatus. This is also true for Pecten (Camptonectes) sp. WOODS, 1906 (= Pecten kaffraria RENNIE, 1930 and Camptonectes woodsi TAVANI, 1940 (objective synonyms), the sculpture is fine, much more so than on NILSSON's figures, but not very different from certain finely ornamented specimens from Maastricht. Most African specimens have a fine sculpture, and thus it is probably true that they are a different "variety" as proposed by E. DARTEVELLE & S. FRENEIX (C. virgatus var. kaffraria). A. VON KOENEN, 1897, described two species from the Cretaceous of Mungo in Cameroon which probably belong with C. virgatus: Pecten productus (p. 20, pI. 3, f. 17) and P. kamerunensis (p. 20, pI. 3, f. 14 a-b, 15 a-b). Pecten (Camptonectes) cf. curvatus as described in R. A. REYMENT, pI. 7, f. 10, is in the B. M. (L 82956). It comes from the Odukpaniformation of the neighbourhood of Calabar (Nigeria). It is very badly preserved and cannot be determined specifically. It is a Camptonectes because some parts have retained the typical ornamentation. Pecten projectus TATE, 1867 (p. 155, pI. 9, f. 6) from the South African Upper Cretaceous is probably a C. virgatus; no decision can be reached without the original or topotypical material. Pecten concentricepunctatus REUSS, 1845 (p. 28, pI. 39, f. 8): undoubtedly a Camptonectes species with very fine sculpture; whether this species is specifically different from finely ornamented C. virgatus (NILSSON) or from C. striatopunctatus (ROEMER) I have not been able to decide. Pecten occultestriatus ZITTEL, 1866 (p. 109, pI. 17, f. 6 a-c) seems to be identical with the preceding taxon and the problem is the same. ZITTEL's type-material is in Vienna (fig. 6 a & c in the Geologische Bundesanstalt and f. 6 b in the Naturhistorisches Museum). On specimens of C. virgatus from Edward's Pit, Mousehold, Norwich, B. mucronata zone (B. M.) and from Balsberg (Sweden), Campanian (Lund) a concentric, slightly elevated macrosculpture is visible; these concentric ridges could here too be the result of the fossilisation process. In the North American Cretaceous several species have been described which closely resemble C. virgatus. A few examples: Camptonectes burlingtonensis (GABB, 1860) see B. WADE, 1926, p. 63, pI. 20, f. 5, 6, 10, 11) has a more pronounced concentric ornamentation than on most C. virgatus-specimens. C. argillensis (CONRAD, 1860) see B. WADE, 1926, p. 62, pI. 20, f. 8, 9): on figures this species cannot be differentiated from specimens of C. virgatus from Norwich and Balsberg. Both species are from the Campanian-Maastrichtian. C. martinensis (STEPHENSON, 1952, p. 80, pI. 19, f. 1-4) C. ellsworthensis (STEPHENSON, 1952, p. 80, pI. 19, f. 5, 6) C. moodyi (STEPHENSON, 1952, p. 79, pI. 19, f. 8, 9) These 3 species are from the Texan Cenomanian; from the descriptions and figures no real specific differences can be found and they seem to be almost identical with the specimens from Le Mans (also Cenomanian). Differentiation: C. virgatus and C. striatopunctatus are very similar and likely to be very closely related; C. virgatus is probably the direct descendant of C. striatopunctatus. C. striatopunctatus dies out at the end of the Albian and C. virgatus appears at the beginning of the Cenomanian. The main difference between the two species is that the average C. striatopunctatus has a much finer and less clearly visible ornamentation: on most specimens it is only visible under magnification. As an illustration of the grade of difference between C. virgatus and C. striatopunctatus PERVINQUIERE's, 1912 opinion is reproduced: "Avec ZITTEL et HOLZAPFEL, j'estime qu'il est impossible de separer les formes cenomaniennes des senoniennes; d'autre part, il y a tous les passages entre Ie mode a cotes tres fines et Ie mode a cotes relativement larges. Bien des Mollusques actuels nous montrent, au sein de la meme espece, des differences comparables a celles qu'on observe entre formes du Cretace superieur, et meme entre celle-ci et P. striato-punctatus. Au fond, c'est la meme espece qui a vecu pendant tout Ie Cretace». C. virgatus is the only species with C.? milleri (SOWERBY) amongst Cretaceous Camptonectes species with really macroscopic diverging striae. For the differentiation between C. virgatus and C. ? milleri: see under C. ? milleri. Generic attribution: Pecten virgatus NILSSON bears the Camptonectes-sculpture and does not have any sculpture apart from concentric and very pronounced diverging radial lines and thus this species undoubtedly belongs to the genus Camptonectes and its correct name is Camptonectes (Camptonectes) virgatus (NILSSON).» DHONDT, A. V. 1972. Systematic revision of the Chlamydinae (Pectinidae, Bivalvia, Mollusca) of the European Cretaceous. Part 1: Camponectes. Bulletin de l’Institut Royal des Sciences Naturelles de Belgique, 48 (3): 1-60, pls. 1, 2. [p. 27-30]
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Camptonectes (Camptonectes) virgatus (S. Nilsson, 1827); A. V. Dhondt, 1972, Systematic revision of the Chlamydinae of the European Cretaceous, Part 1: Camponectes, plate 2, figures 1a-1c.
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