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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O.A. Lebedev. A new tetrapod from Russia<br />
83<br />
Fig. 2. Jakubsonia livnensis gen. <strong>and</strong> sp. nov., interorbital fragment of the skull roof, PIN 2657/<br />
346. A, dorsal view; B, ventral view.<br />
Jakubsonia livnensis Lebedev, sp. nov.<br />
Etymology. After the town of Livny.<br />
Holotype. PIN 2657/346, the interorbital part of the skull roof, including the frontals,<br />
anterior part of the parietals <strong>and</strong> almost complete postfrontals preserved in natural<br />
contact.<br />
Diagnosis. As for the genus.<br />
Locality <strong>and</strong> horizon. Gornostayevka quarry, SW of the Livny Town, Oryol Region,<br />
Central Russia, ? triangularis-crepida Zone of the St<strong>and</strong>ard conodont scale, Zadonskian<br />
Regional Stage, Lower Famennian, Upper Devonian.<br />
Description <strong>and</strong> comparisons. Skull. The holotype PIN 2657/346, a fragment of the<br />
interorbital part of the skull roof (Fig. 2) includes the frontals, anterior part of the<br />
parietals <strong>and</strong> completely preserved postfrontal from the left side <strong>and</strong> its anterior half<br />
from the right side preserved in natural contact. The dorsal side of this fragment is<br />
ornamented with pit-<strong>and</strong>-ridges sculpturing characteristic of all known Devonian<br />
tetrapods. The pits are more <strong>un</strong>iform in size <strong>and</strong> isometric at the parietals <strong>and</strong> the<br />
postfrontals; in the central part of the frontals they are much deeper, <strong>and</strong> their outline is<br />
irregular. In the anterior part of the frontals these pits even partly merge forming a short<br />
deep groove.<br />
The anterior, frontal part of the holotype slopes ventrally with respect to the parietal<br />
part at an angle of approximately 20º. The frontals <strong>and</strong> parietals are fused without any