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Ž. Žigaite. New telodont from Tuva and Mongolia 163
Fig. 3. Talimaalepis rimae gen. et sp. nov., cephalo-pectoral scale, horizontal longitudinal thin
section (B is part of A). Lake Basin outcrop No 21, north west Mongolia; Chargat Formation,
Salhit Regional Stage, Upper Llandovery – Wenlock, Lower Silurian. Thin section No 80, Institute
of Geology and Geography, Lithuania. Abbreviations: a – anastomoses; dc – thin dentine canals;
spc – single pulp canal; thdc – thick dentine canals. Scale bars: 100 µm.
canal makes a substantial difference, as in Helenolepis scales, there are three or more
pulp canals, subject to a number of crown segments (Karatajūte-Talimaa 1978, p. 236,
Fig. 14). Sparse anastomoses of usually straight dentine canals make the histology of
the scales closer to that of genus Loganellia. Scales with sensory pore canal system
elements are described in Family Phlebolepididae, Loganelliidae, Shieliidae,
Boothialepididae, Turiniidae, and in Furcacaudifrmes (Gross 1968, Märss 1979, Miller
and Märss 1999, Märss 1999, Märss and Miller 2004, Turner 1991, Wilson and Caldwell
1998). On the basis of a different central part of the crown, and shorter lateral areas, as
well as the presence of a single pulp canal, the taxon can be ascribed neither to genus
Loganellia, nor to Helenolepis.
Distribution. Apart of the type locality, remains of Talimaalepis rimae gen. et sp. nov.
are found in several localities of the Central Tuva: outcrop Kyzyl-Tchiraa (Kyzyl-Tchiraa
Formation, Kyzyl-Tchiraa Regional Stage, upper Llandovery), outcrop Elegest
(Dashtygoi Formation, Dashtygoi Regional Stage, upper Wenlock), Kadvoj sequence
(Tchergak Formation, Angatchi and Dashtygoi regional stages, upper Llandovery and
upper Wenlock).
1/247, cephalo-pectoral scale; J, LGI M-1/243, cephalo-pectoral scale; K, LGI M-1/245, cephalopectoral
scale; L, LGI M-1/229, cephalo-pectoral scale; M, LGI M-1/219, precaudal scale; N,
LGI M-1/249, pinnal scale; O, LGI M-1/221, pinnal scale. Scale bars: A, B, 100 µm; C, D, F, G,
J, L, 200 µm; E, H, I, N, 300 µm; O, 400 µm; K, M, 500 µm.