Spondylus serratus H. Woods, 1901
WOODS, H. 1899-1903. A monograph of the Cretaceus Lamellibranchia of England. Vol. I: 1-232, pls. 1-42. Paleontological Society Monograph. The Paleontographical Society. [p. 124, pl. 21, figs. 6a-6c, 7a-7c]
1901 Spondylus serratus H. Woods, 1901
H. Woods, 1899-1903, plate 21.
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«Description.— Shell rounded, outline rather irregular, slightly inequilateral; height and length nearly equal.
Right valve flattened or slightly concave, with numerous parallel, concentric, and spiny laminae and faint radial ribs. Left valve moderately convex, except in small forms; ornamented with numerous small ribs, which are of equal size except on the earlier parts of the shell, where new ribs are being introduced; all the ribs bear many small spines, placed regularly, but on the old parts of the shell the ribs may be nearly smooth. The grooves are broader than the ribs, moderately deep, and crossed by well-marked but somewhat irregular, transverse, thread-like ribs. Ears with four or five ribs. Measurements:
(1) Upper Chalk (Uintacrinus-bed), Devizes Road, Salisbury.
(2) Upper Chalk, locality unknown. (3) Upper Chalk (Uintacrinus-bed) , Newgate, Thanet. Affinities.— This is similar in form to S. latus, but is distinguished by the small and regular spines, and the broader grooves between the ribs. S. Royanus, d'Orbigny,¹ differs from this species in having stronger ribs at regular intervals, and in being proportionately higher.
S. asper, Goldfuss,² is similar in form, but the spines are coarser, fewer, and less regular. S. occultus, Greinitz,³ is a very small (7 mm.) form, which may be closely related to S. serratus, but the ribs appear to be more unequal and to bear tubercles which are in contact, instead of spiny processes distinctly separated from one another. Remarks.— This is a very rare species; I have seen only five examples which could be definitely referred to it. Distribution.— Marsujntes-zone (Uintacrinus-bed) of Devizes Road, near Salisbury, and the Thanet coast.» ¹ ' Pal. Franç. Terr. Crét.,' vol. iii (1847), p. 671, pl. cccclx, figs. 1-5.
² ' Petref. Germ.,' vol. ii (1836), p. 96, pl. cvi, fig. 1. ³ "Das Elbthalgeb. in Sachsen" (' Palaeontographica,' vol. xx, pt. 1). p. 207, pl. xlvi. fig. 1. HENRY WOODS, 1901
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Description. Distinguished from other Spondylus species by its regular pattern of ribs, which is quite different from that seen in other species, and by its concentrically aligned fine tubercles or small spines. Distinguished from S. latus by its broader intercostal grooves and ribbed ears.
Remarks. A free-living species in its adult stages. Occurrence. Santonian, U. socialis and M. testudinarius zones; Wiltshire and Kent; rare. CLEEVELY, R. J. & N. J. MORRIS. 2002. Introduction to molluscs and bivalves. In A. B. Smith & D. J. Batten (Eds.): Fossils of the Chalk, 99-160. The Paleontological Association. London. [p. 134]
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Spondylus serratus Woods; R. J. Cleevely & N. J. Morris, 2002, Introduction to molluscs and bivalves, plate 22, figures 7, 8.
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