Atraktoprion podolicus, Szaniawski & Drygant, 2014

Szaniawski, Hubert & Drygant, Daniel, 2014, Early Devonian scolecodonts from Podolia, Ukraine, Acta Palaeontologica Polonica 59 (4), pp. 967-983 : 978-980

Atraktoprion podolicus sp. nov.

Fig. 8A–H, M.

Etymology: In reference to its type region Podolia, Ukraine.

Holotype: Right MI, ZPAL Sc8./14.1 (Fig. 8F).

Type locality: Ivanye Zolote, Podolia, Ukraine.

Type horizon: Upper part of the Ivanye Horizon, middle part of the section 76, Pragian.

Material. —4 right MI (two of them incomplete) and 6 left MI (ZPAL Sc.8/4.18, 4.19, 4.20, 7.15, 8.4, 8.24, 11.1, 14.1, 14.3, 14.4), samples S.Zo.4, S.Vy.3, S.I.Z.4, 10, 16, 18, S.Uste.2,

Fig. 8. SEM micrographs of atraktoprionid and skalenoprionid scolecodonts from Lower Devonian of Podolia: Chortkiv Horizon, section 70 (A, B, G, → K), section 71 (J); Ivanye Horizon, section 58 (M), section 76 (C, D, E, F, H, I); Borshchiv Horizon, section 48 (L); Silurian–Devonian transition beds, section 64 (N, O). A–H, M. Atraktoprion podolicus sp. nov., Middle Lochkovian–Lower Pragian. A–D. Left MI. A. ZPAL Sc.8/4.19; sample S.Zo.4, in dorsal view. B. ZPAL Sc.8/4.20, sample S.Zo.4, in ventral view. C. ZPAL Sc8/14.3, sample S.Uste.2, in oblique dorsal (C

1

) and dorsal (C

2

) views. D.

ZPAL Sc.8/11.1, sample S.IZ.10, in dorsal view. E. ZPAL Sc.8/7.15, sample S.IZ.18, in dorsal view. F. ZPAL Sc.8/14.1, holotype, sample S .IZ.4, right

MI in lateral (F 1) and dorsal (F 2) views. G. ZPAL Sc.8/4.18, sample S.Zo.4, incomplete and deformed right MI in dorsal view. H. ZPAL Sc.8/14.4, sample S.IZ.4, incomplete right MI in dorsal view. M. ZPAL Sc.8/8.24, sample S.IZ.16, right MI in dorsal view. I. Atraktoprion ? sp. A, Middle Lochkovian, ZPAL Sc.8/5.4, sample S.Vy.3, left MI in dorsal (I 1) and right lateral (I 2) views. J, K. Atraktoprion ? spp., Middle Lochkovian. J. ZPAL Sc.8/4.17, sample S.Zo.2, right MII in dorsal (J 1) and right lateral (J 2) views. K. ZPAL Sc.8/2.3, sample S.Kh.1, left MII in dorsal view. L. Skalenoprion sp. , Lower Pragian, ZPAL Sc.8/10.1, sample S.Za.11, incomplete right MI in dorsal view (L 1) and posterior, inner part (L 2). N, O. Skalenoprion sp. A . N. ZPAL Sc8/13.2, sample S.Dn.1, left MI in dorsal view (anterior portion of the hook broken off during preparation). O. ZPAL Sc8/13.1, sample S.Dn.1, right MI in dorsal view.

from Chortkiv and Ivanye horizons, Middle Lochkovian– Pragian, Podolia.

Diagnosis. —Right MI wide, with wide bight extending for about 0.4 of the jaw length. Hook stout with apical part bent posteriorly. Inner margin beneath the hook slightly convex, denticulated. Outer margin nearly straight, directed postero-laterally. Left MI with outer margin slightly oval, inner margin beneath the hook nearly straight, denticulated, posterior margin directed postero-medially. Inner wing in the anterior part wide, narrowing posteriorly.

Description. —Right MI about two times longer than wide. Length of both complete specimens below 0.5 mm. Hook stout with apical part bent posteriorly. Denticulated inner margin bears 8–10 posteriorly inclined denticles. First 3 to 4 of them slightly increase in size posteriorly and the rest decrease. Outer margin beneath the hook nearly straight, directed postero-laterally. Bight very wide with anterior margin oval shaped. Shank short, nearly triangular. Left MI with hook slightly longer than 1/3 of the jaw length. Inner, denticulated, margin slightly convex, bears 8–9 denticles differentiated in size, similarly as in right MI. Outer margin slightly convex. Posterior margin directed postero-medially, slightly concave in the middle part. Inner wing begins at the level of the second denticle, wide in the anterior part, gradually narrows posteriorly. The posteriormost portion of the jaw sub-triangular, with vertical concavity in the middle. Opening of the pulp cavity long, extends to the basal part of the hook.

Comparisons. —Right MI is most similar to Leptoprion ? sp. described by Tonarova et al. (2012) from Ludlow of Prague Basin but is narrower from it and has slightly less curved hook. It is also similar to the Middle Devonian jaws described by Stauffer (1939) as Arabellites anatinus but differs from them with smaller hook and narrower shank. Left MI is somewhat similar to Arabellites elegans Hinde, 1879 (illustrated also by Eriksson 2008: fig 1.11) but differs from it by less curved hook, larger number of denticles and triangular posterior end. Both MI of the new species are somewhat similar to those of Atraktoprion eudoxus Szaniawski, 1968 from the Permian of Poland, but right MI of the new species has smaller hook and left MI differ in shape of posterior portion.