Neithea striatocostata (Goldfuss, 1833)
GOLDFUSS, A. 1833-1840. Petrefacta Germaniae tam ea, quae in museo universitatis regiae Borussicae Fridericiae Wilhelmiae Rhenanae servantur quam alia quae cunque in museis hoeninghusiano, muensteriano aliisque extant, iconibus et descriptionibus illustrata. Zweiter Theil, 312 p., pls. 1-199. Arnz & Co., Düsseldorf [p. 55, pl. 93, figs. 2a-2g]
1833 Pecten striatocostatus Goldfuss, 1833 [partim]
1844 Pecten elegans Reuss, 1844
1847 Janira truellei Orbigny, 1847
1906 Neithea böckhi Pethö, 1906
1918 Pecten (Neithea) woodsi Woldrich, 1918
1927 Neithea philippsoni Boehm, 1927
1844 Pecten elegans Reuss, 1844
1847 Janira truellei Orbigny, 1847
1906 Neithea böckhi Pethö, 1906
1918 Pecten (Neithea) woodsi Woldrich, 1918
1927 Neithea philippsoni Boehm, 1927
A. Goldfuss, 1833-1840, plate 93.
|
«Fig. 2. a Valva sinistra adulta. Eine ältere linke Schale.
b. Pars eius aucta. Ein vergrössertes Stück derselben. c. d. Valva sinistra iuvenilis. Eine junge Schale. e. Pars lente aucta. Ein vergrössertes Stückchen. f. g. Valva dextra, a facie externa et interna. Eine rechte Schale, von aussen und innen. Pecten testa ovato-trigona inferne sexangulata concentrice lineata, valva dextra plana, ptlicis sex lineatis, sinistra convexo-gibba, costis senis elatis costulatis, binis minoribus lineisque interstitialibus interpositis, auriculis subaequalibus costulatis.
Faujas m. St. P. tab. 2A. fig. A.
E creta tofina montis St. Petri et chloritea Westphaliae. M. B. et M. M. Auch diese Art hat ganz die äussere Form der beiden vorigen, unterscheidet sich jedoch sehr deutlich durch die Beschaffenheit ihrer Rippen. Die 6 hochgewölbten Rippen der linken Schale sind durch Furchen in 3—5 kleinere abgetheilt, welche Abtheilung bei den älteren Schalen sehr verwischt, bei den Jüngern aber deutlich ausgedrückt ist. Mit zunehmendem Alter erheben sich diese Rippen immer mehr und mehr und erscheinen durch Abnutzung ganz glatt und abgerundet. Je zwischen zweien derselben liegen 2 kleinere, welche öfters durch einige Linien abgetheilt sind und zwischen ihnen findet sich eine schmale Linie. In den auf diese Weise sehr verengten Zwischenfurchen bemerkt man concentrische Querlinien, welche aber bei alten Schalen selten erhalten sind. Die rechte, flach-coneave Schale hat 6 Falten, deren Ecken am Rande vortreten. Auf ihrer inneren Fläche zeigt sie dieselben Furchen wie die vorige Art, auf der äusseren aber ist sie mit gedrängten, abwechselnd breiteren und schmäleren Linien bedeckt, welche gewöhnlich paarweise stehen und Strahlenbüschel darstellen. Diese sind gewöhnlich durch mehrere dicke Wachsthumsabsätze unterbrochen. — Findet sich im Kreidetuff zu Mastricht und in der chloritischen Kreide bei Coesfeld, Dülmen und Lemförde.»
AUGUST GOLDFUSS, 1833
|
«Discussion
— Neithea striatocostata has been recognized as a very variable species in areas where it occurs frequently, such as the Late Maastrichtian deposits near Maastricht (Netherlands) (Dhondt, 1973). In the same article I described N. sexangularis from the Campanian of the Charente as a separate species which had evolved from N. striatocostata and had similar (but more strongly developed) characteristics: more strongly prominent principal ribs, more intercostal riblets, and a wider disc. The relatively numerous material from the sections of the A 10, despite its often poor preservation, shows that in the lower and middle Campanian exposures N. striatocostata has a wider and slightly different variability than it does in the underlying Santonian and in the overlying uppermost Campanian strata. N. sexangularis is an extreme of this wide variability series: the intercostal riblets are slightly thinner and more numerous, the principal ribs are somewhat more sharply angular, especially near the ventral margin. To draw attention to this change in variability I have kept N. striatocostata and N. sexangularis as separate taxa, but do not believe that they form separate biological entities. The change in variability in the Campanian may be due to a change in environmental conditions.» DHONDT, A. V. 1985. Late Cretaceous bivalves from the A 10 exposures in Northern Aquitaine. Cretaceous Research, 6 (1-2): 33-74, figs. 1-6. [p. 43]
|
Neithea striatocostata (Goldfuss, 1833), figure 2c; Neithea sexangularis (d’Orbigny, 1847), figure 2d; A. V. Dhondt, 1985, Late Cretaceous bivalves from the A 10 exposures in Northern Aquitaine, figure 2.
|
«Synonymy.— GOLDFUSS, plate 93, figures 2 a-g: Pecten striatocostatus.
In fact figure 2, a, b, f , g belong to Neithea striatocostata, but 2, c, d, e belong to Neithea sexcostata (WOODWARD, 1833). A. D'ORBIGNY, 1847 chose and decided that "pl. 93, figures 2, a, b (exclus. fig. c, d)" belonged to Janira striatocostata. This is the first choice and thus for nomenclatorial purposes the valid one. GOLDFUSS types have intercalary ribbons rather than ribs. A. D'ORBIGNY, 1850 retracted his previous opinion: he places 508 "Janira striatocostata D'ORB., 1847¹¹. Pecten id., GOLD. 2, p. 55, pl. 93, fig. 2, Westphalie, Koesfeld, Lemford (sic)" in the 20e étage (the Cenomanian). The explanation probably lies in the fact that he associated "chloritische Kreide" with "craie chloritée" and thus it would be Cenomanian, whereas it belongs to Campanian strata. To remain consistent with himself he had to give another name to the Senonian species. This is the reason for the name Janira substriatocostata D'ORBIGNY. For nomenclature the first choice, from the Paléontologie française, remains the valid one and consequently the name from the prodrome (Janira substriatocostata) is invalid, being an objective synonym (both species have the same type). D'ORBIGNY's specimens, kept in the Muséum national in Paris, and taking into account the very wide variability mentioned above for the rib structure, do not allow us to doubt that indeed they belong to the species N. striatocostata (GOLDFUSS). The lectotype 7618 F, figured by J. ROGER N.S. 50, figures 1, a, b is a very worn specimen of the form with two well developed intercalary ribs. 7618 from Royan has been determined by ROGER (N.S. 50, 1955) as Neithea böckhi (PETHOE); as far as I can make out, it is just another specimen with 2 very developed prominent intercalary ribs, and there seems to be no reason to ascribe it to another species than N. striatocostata. (...)
Differentiation.— The only species which really shows a great similarity to N. striatocostota is Neithea sexangularis (D'ORBIGNY). The general shape is almost the same but N. sexangularis has more prominent digitations and is relatively broader. The distribution of the radial striation is also different: in N. sexangularis the close and very numerous striae delimit thin ribbons which cannot be counted and appear to be very irregularly placed.
The confusion between N. striatocostata and N. alpina which exists in German literature is the consequence of not giving sufficient importance to the radial striation on the whole shell and particularly on the areas and to the direction in which these areas are bent. More confusion is found in specimens which are very worn; those with only worn ribbons in their intervals might suggest N. atava (ROEMER). Even in the strongly corroded state a difference exists because on N. atava the areas are smooth and the auricles are smooth, equal and smaller. When the principal ribs are divided into 3, and the intercalary ribs are well developed, one could mistake N. striatocostata for N. quinquecostata (SOWERBY). As ROGER mentions on fiche 50 this has happened on plate 13, figure 10, and plate 15, figure 12 in PETHOE, 1906. It could indeed be as ROGER states, but I would like to remark that PETHOE's figures are not very good and that he explicitly states in the text that all ribs are radially striated. N. sexcostata (WOODWARD) differs from N. striatocostata by smaller auricles, relatively greater U.P.D., and much smaller average size. The other Neithea-species can easily be differentiated by the number of intercalary ribs and the absence of radial striation on their ribs.» (¹¹) D'ORBIGNY, 1847 in de prodrome is the date of the Prodrome-manuscript and not the date of the paléontologie Française, to which D'ORBIGNY gives the date 1845 or 1846 (again the date of the manuscript).
DHONDT, A. V. 1973. Systematic revision of the subfamily Neitheinae (Pectinidae, Bivavia, Mollusca) of the European Cretaceus. Mémoires du Institute Royal des Sciences Naturelles de Belgique, 176: 1-101, pls. 1-5. [p. 51, 52]
|
Neithea (Neithea) striatocostata (A. Goldfuss, 1833); A. V. Dhondt, 1973, Systematic revision of the subfamily Neitheinae of the European Cretaceus, plate 3, figures 2a-2d.
|