UTRECHT MICROPALEONTOLOGICAL BUllETINS

(LINDSTROM), emend. herein (see PI. 8, fig. 9). It differs from the latter in
the following points:
- The cusp is more strongly reclined and straighter.
- The antero-basal extension is relatively smaller.
- The oral edge is much longer and less convex.
Regional occurrence: At Kopingsklint the species was found from the base
of the Bruddesta Formation up to a level at about 0.50 m. over that base. In
section 6 it was found in an interval from 0.50 m. up to 1.00 m. above the
base of the Bruddesta Formation. Near Horns Udde it occurs in an interval
from 0.10 m. up to about 0.90 m. above the base of the Bruddesta
Formation.
Biostratigraphic range: Prioniodus crassulus was found in the Prioniodus
crassulus Assemblage Zone and in the Prioniodus navis/Prioniodus crassulus
AsseJ!1blageZone (fig. 15).
Prioniodus deltatus (LINDSTROM), emend. VAN WAMEL, herein
(PI. 8, figs. 1-9)
Acodus deltatus LINDSTROM, 1955a, p. 544, PI. 3, fig. 30.
Drepanodus latus LINDSTROM, 1955a, p. 564, PI. 3, figs. 22, 23.
Acodus deltatus altior LINDSTROM, 1955a,p. 544, PI. 3, figs. 27-29.
Distacodus rhombicus LINDSTROM, 1955a, p. 556, PI. 3, figs. 35, 36.
Trichonodella longa minor LINDSTROM, 1955a, p. 601, PI. 6, figs. 16-19.
Oistodus linguatus LINDSTROM, 1955a, p. 577, PI. 3, figs. 39-41.
Prioniodina diprion LINDSTROM, 1955a, p. 587, PI. 5, fig. 43.
Remarks: This multi-element species is usually composed of undenticulated
elements. Their basic plans are quite comparable with those of the denticulated
elements of other species of the genus Prioniodus PANDER, emend.
herein. Occasionally, denticle-like configurations of the keels may occur. See
for example PI. 8, figs. 3, Sa, band 7.
The prioniodiform element (see PI. 8, fig. 1) is Acodus deltatus
LINDSTROM, 1955. The form variation in this element is rather large. For a
differential diagnosis with the prioniodiform element of Prioniodus crassulus
(LINDSTROM), emend. herein, see the description of the latter species on
page 83.
The prioniodinaform element (PI. 8, fig. 2) is Drepanodus latus
LINDSTROM, 1955. Prioniodina diprion LINDSTROM, 1955, is considered
as a rather sparse variant of the prioniodinaform element, with denticle-like
modifications of the oral keel (PI. 8, fig. 3).
The gothodiform element (PI. 8, fig. 4) is Acodus deltatus altior
LINDSTROM, 1955.