Zemes un vides zinātnes Earth and Environment Sciences - Latvijas ...

90 ADVANCES IN PALAEOICHTHYOLOGY
the popliteal from the fibular fossa in Tulerpeton (Lebedev and Coates 1995). It supports
the ventral corner of the fibular condyle and is termed here the fibular ridge (fr).
The fibular ridge limits the posterior face of the distal part of the femur ventrally
(Fig. 6D). The ventral part of this surface distally is occupied by a very large triangular
elongated fibular fossa, the size of which, as that of the popliteal fossa, exceeds the
sizes of corresponding structures in all known Devonian tetrapods.
In cross-section the distal part of the femur is shaped roughly as an equilateral
triangle, with its base slightly arched outwards (anteroventrally) at the expense of the
overhanging tibial condyle. The distal articulating surface is very well ossified, but
incompletely preserved. The only intact area is the central part of the tibial facet adjoining
the crest, which separates it from the fibular facet. The latter is completely destroyed
(Fig. 6).
Cranial bone questionably assigned to Jakubsonia livnensis gen. and sp. nov. (Fig. 8).
The posterior part of the skull roof PIN 2657/348 includes an unpaired postparietal,
the anterior part of the right tabular, right supratemporal, fragments of the right parietal
and left supratemporal. The only well preserved margin of this specimen is the posterior.
The feature which might suggest attribution of the specimen to tetrapods is the
characteristic pit-and-ridges dermal sculpturing of the same type as found in the fragment
of the interorbital part of the skull roof described above (PIN 2657/346). However, the
Fig. 8. ? Jakubsonia livnensis gen. and sp.
nov., posterior part of the skull roof, PIN
2657/348. A, dorsally, B, ventrally, C, line
drawing of B. Abbreviations: Pa, parietal;
Pp, postparietal; St, supratemporal; Ta,
tabular.