Conus (Conchlioconus)
gradatus (Yokoyama, 1928)
Descrizione.
Yokoyama
(1928 : 338, pi. 66, figs. 3, 4) described and figured two specimens from the Pliocene of Japan as Cochlioconus
gradatus gen. et sp. nov. The new genus was not explicitly referred to any
family, but it was described as " Conus-like " and Yokoyama stated that " The
presence of a deep sutural notch reminds us of the genus Conus." Pilsbry
saw this paper and wrote to Yokoyama, drawing his attention to the similarity between Cochlioconus
and Thatcheria. Yokoyama then stated in a subsequent paper (1930) that he
regarded Thatcheria (T. mirabilis} and Cochlioconus (C. gradatus) as
congeneric, though not conspecific, the Pliocene species being more Conus-like in appearance than
the Recent form. He did not, however, change his views on the systematic
position of the genus, for he wrote (p. 406) " I think I am right in placing it near Conus.
This opinion seems to be also shared by Mr. Pilsbry as is evident from his
communication." He also stated, probably wrongly, that Angas' specimen of T.
mirabilis may be the only one now
existing [i.e., in a collection] in the whole world."
Epoca:
Pliocene
|
© The
University Museum, The University of Tokio |
Conchlioconus
gradatus
(Yokoyama, 1928)
Thatcheria
gradata (Yokoyama, 1930) Thatcheria mirabilis
(Makiyama, 1959) Syntype |
Bibliografia
·
(1) - Yokoyama, M., 1928. Journal
of the Faculty of Science, Tokyo Imperial University, sect. 2. vol. 2 (pt. 7 )