UTRECHT MICROPALEONTOLOGICAL BUllETINS

Remarks: In our material this species show~ a vanatlOn similar to that
mentioned for Cordylodus angulatus PANDER (see p. 58). Especially the
sidewards bending of the cusp and the number of denticles may vary
strongly. As Cordylodus oklahomensis differs only from Cordylodus prion by
its sideward bending and the fact that it has only three denticles (according
to Muller, 1959) the former species name is considered to be a junior
synonym of the latter. Druce & Jones (1971, p. 69) remarked that Cordylodus
oklahomensis would be distinguishable from Cordylodus prion by the
"lateral flaring of the inner cavity lip" of the former species. As Lindstrom
(1955a, p. 553) stated already, that the base of Cordylodus prion "may be
widened at the inner side", also this feature seems to lose diagnostic value
for a differentiation.
Cordylodus lindstromi, according to its type description "is very similar to
Cordylodus angulatus and Cordylodus prion)} (Druce & Jones, 1971, p. 69)
and only the presence of additional apices below the denticles of the
posterior process would be distinctive. In one of our samples, however,
variation of Cordylodus prion was found to include variants with and others
without additional apices (see PI. 1, fig. 8 and 9). Both these forms are
considered to be within the range of variation of the species Cordylodus
prion LINDSTROM.
As in Cordylodus angulatus, specimens of Cordylodus prion are frequently
broken between the cusp and first denticle or between the first and second
denticle.
Regional occurrence: At Kopingsklint the species was found from the base
.of member Da. d 2 up to the top of member Dk 1. Between Aleklinta and
Djupvik, in the conglomerate halfway member Da. d3 , near Horns Udde in
member D h1 .
Biostratigraphic range: Codylodus prion LINDSTROM was found from the
Cordylodus angulatus/Cordylodus prion Assemblage Zone up to and including
the Drepanoistodus numarcuatus/Paroistodus amoenus Assemblage
Zone (fig. 15).
Cordylodus rotundatus PANDER, 1856
(PI. 1, fig. 14)
Cordylodus rotundatus PANDER, 1856, p. 33, PI. 2, figs. 32,33. LINDSTROM, 1955a, p. 553, PI. 5,
figs. 17-20, Fig. 3F.
Regional occurrence: At Kopingsklint the species occurs from the base of
member Da- d 2 up to and including the basal portion of member Kk l' In
section 6 from member Ka- d 1 up to the top of member Ka- d 2. Near Horns