Janupecten polemicus (Marwick, 1928)
MARWICK, J. 1928. The Tertiary Mollusca of the Chatham Islands including a generic revision of the New Zealand Pectinidae. Transactions and Proceedings of the New Zealand Institute, 58 (4): 432-506. [p. 451]
1928 Serripecten polemicus Marwick, 1928
Pecten hochstetteri; A. Zittel, 1864, Fossile Mollusken und Echinodermen aus Neu-Seeland, plate 11, figures 5a, 5b.
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«When Zittel (1864, p. 50) deseribed P. hochstetteri, he had material belonging to two species, the first with two smooth, shining valves, the second with the left valve finely concentrically striated and the right with obsolete radials. That this was so can be proved by several lines of evidence. Thus his figures, supposed to show a right and a left valve are really of two right valves. Also in his description he says the left valve is " laevigata, interdum striis concentricis ornata." This includes the two species, for the shell with a radially ribbed right valve always has a concentrically striated left valve, not a smooth one; though, as pointed out to me by Dr. Finlay, this could refer to weathered material of the ribbed species. The localities given by Zittel are Whaingaroa and Aotea, Auckland; and Cape Farewell, Nelson. At Whaingaroa and Aotea both species occur, but at Cape Farewell only the smooth shell is found. The evidence of the localities alone shows that two species were confused; and since the locality is a vital part of a description, it cannot be assumed that Zittel's description applies to only one species. Further, Zittel said that the left valve was smooth or concentrically striate, and the right valve weakly ribbed. The statement, as it stands, applies to the ribbed shell accurately enough; but quite possibly this agreement is apparent only. Whether Zittel regarded the byssal notch as anterior or posterior is not clear. At the time he wrote, opinion was divided on the subject, and the descriptions of other species in the "Novara" publication are not conclusive. The evidence afforded by P. athleta, however, seems to indicate that Zittel's left valve was what we call the right. Also, fig. 5a of P. hochstetteri, said by him to be a left valve, shows the byssal sinus plainly, whereas in the original of fig. 5b the ears are badly broken. This tends to show that the smooth right valve figured by Zittel was used by him for his description of the supposed "left" valve, and was not mistaken by him for a true left valve in the modern sense. At all events, there can be no doubt that Zittel handled two species and that his description and figures include both. Therefore, when Hutton (1873, p. 30) selected the shell with two smooth valves as hochstetterii and expressly excluded the ribbed shell he was quite within his rights, and the choice cannot be altered. His reference is "Zittel, Voy. Novara, Palae., .p. 50, pI. XI, f. 5a, not 5b." This course was approved by Tate (1886, p. 114) who correctly stated that the shell having a ribbed valve was apparently related to P. yahlensis T.-Woods.
Hutton's deliberate choice of the smooth shell for P. hochstetteri was overlooked by Park (1905, p. 485) who took it for granted that P. hochstetteri should refer to the ribbed one (Zittel, pl. 11, f. 5b) and gave the name Pseudamussium huttoni to the smooth. P. huttoni is therefore a synonym of P. hochstetteri and the latter must be used. The species with a weakly-ribbed right valve and a concentrically lined left one being without a name, Serripecten polemicus is proposed, and a specimen from loc. 993, coast, section 70, block 19, Whaingaroa Survey District, is chosen as type.» JOHN MARWICK, 1928
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