Eopecten abjectus (Phillips, 1829)
PHILLIPS, J. 1829. Illustrations of the Geology of Yorkshire or a description of the strata and organic remains of the Yorkshire coast. Printed for the author, by Thomas Wilson and Sons, High-ousegate. 192 pp. York. [p. 129, pl. 9, fig. 37]
1829 Pecten abjectus Phillips, 1829
1863 Hinnites gradus Bean in Lycett, 1863
1863 Hinnites gradus Bean in Lycett, 1863
«2. DIAGNOSIS
Distinguished from E. spondyloides by the tendency for two median costae to be considerably larger and bear tubercles. Distinguished from E. velatus by the tendency for intercalary costae to rapidly gain the same height as original costae.
3. DESCRIPTION
Essentially very similar to E. spondyloides apart from the diagnostic features. The number of costae on the left valve is however usually much smaller (e. g. 40 at H: 53.5, OUM J2291) at equivalent size,and convexity, although very variable, is usually much higher (CL : 21.5 at H; 58, BM 70686). The maximum height is 127.5 mm (GPIT).
4. DISCUSSION
PHILLIPS' (1829) figure of 'Pecten' abjectus in the first edition of Geology of Yorkshire is a poor illustration of a coarsely ornamented Eopecten. There is little sign of the larger tubercle-bearing costae diagnostic of the species described in Section 3. The figure in the second edition (1835), while undoubtedly of the same specimen, is considerably clearer and yields a costal count of 36 at H: 37. This is a reasonable value for the species described in Section 3 and well below the lower limit of variation in E. spondyloides, the only species with which there is any possibility of confusion. The original specimen seems to have been lost (see above) but in the hght of the above evidence it can be assumed to have been a variant of the species described in Section 3 with relatively undeveloped median costae. The majority of subsequent usage of PHILLIPS' specific name (see Synonymy) has been for representatives of the species described in Section 3 thus there would be good grounds for designating as neotype a typical example of this species.
One of the figures (pl. 14, fig. 3) of 'H.' abjectus in MORRIS and LYCETT (1855) depicts a specimen with the more numerous and regular costae charactenstic of E. spondyloides. LISSAJOUS (1910) states that the specific name gradus BEAN dates from the latter's paper in Ann. Mag. Nat. Hist. (1839). However, there is no reference to the species in this paper and the earliest reference to it would therefore appear to be in LYCETT (1863), where a specimen which clearly belongs to E. abjectus, is described and figured as 'P.' gradus BEAN. 'Spondylus' tuberculosus GOLDFUSS and secondary usages of this specific name are discussed under E. spondyloides. Inadequately characterised secondary references to synonymous species are excluded from the synonymy because of the possibility of misapplication to E. spondyloides. They may be traced in OPPEL(1858), ROTHPLETZ (1886), SCHLIPPE (1888), KILIAN and GUEBHARD (1905), HENNIG (1924), LANQUINE (1929), PARENT (1940), CHANNON (1950) and J.-C. FISCHER (1969).» 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. 159, 160]
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Eopecten abjectus (Phillips 1829); A. L. A. Johnson, 1984, The palaeobiology of the bivalve families Pectinidae and Propeamussiidae in the Jurassic of Europe, plate 6, figures 3, 5, 6, 8, 9, ? figure 1.
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