Zemes un vides zinātnes Earth and Environment Sciences - Latvijas ...
Zemes un vides zinātnes Earth and Environment Sciences - Latvijas ...
Zemes un vides zinātnes Earth and Environment Sciences - Latvijas ...
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D.K. Elliott, E. Mark-Kurik, E.B. Daeschler. A revision of Obruchevia<br />
37<br />
Fig. 7. Perscheia pulla gen et sp. nov. Outline of plates with canals accentuated. A, holotype,<br />
posterior part of the dorsal plate (CMN-NUFV 101); B, dorsal plate fragment (CMN- NUFV<br />
102); C, dorsal plate fragment (CMN-NUFV 103); D, posterolateral part of dorsal plate (CMN-<br />
NUFV 104). Scale bars equal 50 mm.<br />
The internal surface (Fig. 6E) is concavo-convex, shiny <strong>and</strong> smooth. Several growth<br />
lines are present parallel to the curved margin <strong>and</strong> a number of large smooth blisters are<br />
present towards what appears to be the lateral margin of the plate. The basal layer is<br />
dense, laminar, <strong>and</strong> up to 2 mm thick.<br />
The embayment is about 55 mm long <strong>and</strong> has a ro<strong>un</strong>ded natural margin. At one end<br />
it curves towards the outer margin <strong>un</strong>til tr<strong>un</strong>cated by the broken edge, in the other it<br />
meets the broken end of the plate. Although broadly ro<strong>un</strong>ded, the margin shows three<br />
well-developed ro<strong>un</strong>ded ridges, about 5 mm across, that r<strong>un</strong> diagonally from the inner<br />
to the outer surface <strong>and</strong> terminate externally in a blister (Fig. 6G). Part of a fourth is