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

More documents

Recommendations

Info

124 ADVANCES IN PALAEOICHTHYOLOGY Fig. 1. Nostolepis alifera sp. nov. SEM micrographs of scales (A-G), crown views, anterior upwards, and thin section photos (H-L). A, LIGG 25-A-2570; B, LIGG 25-A-2568; C, LIGG 25-A-2632; D, LIGG 25-A-2571; E, LIGG 25-A-2549; F, holotype, LIGG 25-A-2550; G, LIGG 25-A-2553; H-J, vertical transverse section of a scale like that in Fig. 1G. Thin section 3758. H, general view; I, details of the right, and J, of the left crown and bordering base parts; K-L, vertical transverse section through the anterior part of a holotype-like scale. Thin section 3759. K, general view; L, the left part at higher magnification. Lūžņi-4 borehole, depth 197.0 (A-B, H-J), 197.2 (C), 207.0 (D, K-L) and 189.8 (E-G) m. m. Přidoli, Jūra Regional Stage, Garzde Beds of the Targale Formation. Abbreviations: avc, ascending vascular canal, b, bone, bmd, bone-like mesodentine, cvc, circular vascular canal, gl, growth lamella, oc, osteocyte cavity, rvc, radial vascular canal. Scale bars: 0.1 mm.
J. Valiukevičius. Silurian acanthodians from Lūžņi-4 125 Fig. 2. Nostolepis alifera sp. nov. Histological structure of a scale like that in Fig. 1B. Vertical longitudinal section. Thin section 3760. A, general view; B, detail of the scale primordium; C, detail of the posterior part of neck with the neck/base junction; D, detail of the central part of crown. Lūžņi-4 borehole, depth 207.0 m. Přidoli, Jūra Regional Stage, Garzde Beds of the Targale Formation. Abbreviations: avc, ascending vascular canal, b, bone, gl, growth lamella, oc, osteocyte cavity, rvc, radial vascular canal, sg, Stranggewebe, sl, Stranglacuna. Scale bars: 0.1 mm. Description. Morphology. Most (flank) scales have posteriorly elongated rhomboidal to elipsoidal crowns from 0.28 to 0.85 mm long. Rare specialized varieties have triangular crowns. The crown plate slopes down slightly anteriorly. A clear elevated triangular medial area and lower lateral areas are distinguished on the crowns. The medial area carries five to eight sub-parallel anterior ridges with rounded crests that fade out at about half of crown length (Fig. 1 C, E-F). Some scales have unevenly long medial ridges of which some point to or converge with the longest central ridges at the posteriormost crown part (Fig. 1 B, G). Short anterior bifurcation of ridges occurs rarely. The medial crown area sometimes has a wide deep central groove (Fig. 1 G). The lateral crown areas contain one to two ridges extending the whole crown length (Fig. 1 D, G) or short, more numerous oblique ridgelets which converge with the longest medial ridges posteriorly (Fig. 1 A-B). The scale bases are rhomboidal (except for specialized varieties, see Fig. 1 D), slightly (Fig. 1 K) to moderately convex, and separated from the necks by a clear rim. The necks are short anteriorly because of the downsloping crown, and frequently contain large pores (up to five basally on each side, see Fig. 1 C).
Page 1 and 2:
LATVIJAS UNIVERSITĀTES RAKSTI 679.
Page 3 and 4:
LATVIJAS UNIVERSITĀTES RAKSTI 679.
Page 5 and 6:
Contents Ervīns Lukševičs and Ģ
Page 7 and 8:
ACTA UNIVERSITATIS LATVIENSIS, 2004
Page 9 and 10:
Ervīns Lukševičs, Ģirts Stinkul
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Olga Afanassieva. Microrelief on th
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
D.K. Elliott, E. Mark-Kurik, E.B. D
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
C.G.Miller, T. Marss, H. Blom. New
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
ACTA UNIVERSITATIS LATVIENSIS, 2004
Page 59 and 60:
H.-P. Schultze, T. Marss. Revisitin
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74: H.-P. Schultze, T. Marss. Revisitin
Page 79 and 80: ACTA UNIVERSITATIS LATVIENSIS, 2004
Page 81 and 82: O.A. Lebedev. A new tetrapod from R
Page 99 and 100: ACTA UNIVERSITATIS LATVIENSIS, 2004
Page 101 and 102: E. Lukševičs, I. Zupiņš. Sedime
Page 121 and 122: J. Valiukevičius. Silurian acantho
Page 123: J. Valiukevičius. Silurian acantho
Page 149 and 150: V. Pernegre, V. Dupret. Biostratigr
Page 159 and 160: Ž. Žigaite. New telodont from Tuv
show all

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

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?