Kettnerites ŽEBERA, 1935 emend. Šnajdr 1951

Tonarová, Petra & Introduction, 2008, Revision Of Kettnerites Žebera, 1935 (Scolecodonta, Silurian Of The Barrandian Area, Czech Republic): Preliminary Results, Acta Musei Nationalis Pragae Series B 64 (2 - 4), pp. 185-192 : 188

Genus Kettnerites ŽEBERA, 1935 emend. Šnajdr 1951

1964 Kettnerites ŽEBERA ; Tasch and Stude, p. 649, 651

1971 Kettnerites ŽEBERA ; Jansonius and Craig, p. 280, pl. 1

1973 Kettnerites ŽEBERA ; Tasch, p. 459

1985 Kettnerites ŽEBERA ; Männil and Zaslavskaya, p. 117-118

1991 Kettnerites ŽEBERA ; Bergman, p. 249, 253

1999 Kettnerites ŽEBERA ; Eriksson, p. 403

2004 Kettnerites ŽEBERA ; Eriksson et al., p. 269, 278, 281, 283, 284, tab. 1

2008 Kettnerites ŽEBERA ; Eriksson, p. 629, 631, 632

T y p e s p e c i e s: Kettnerites kosoviensis ŽEBERA,

1935.

L o c u s t y p i c u s: Prague Basin, Teplá-Barrandian

Region, Czech Republic.

S t r a t u m t y p i c u m: ”Budňany Limestone” after the original designation of Žebera (1935), Požáry Formation, Přídolí, Silurian.

D i a g n o s i s ( Žebera 1935, p. 95, translation of the Czech and French versions):

Specimens with a sharply terminated posterior base that is largely elongated (= shank). Middle part of the lower margin is thickenned or with a mound that compose a spur. The anterior part of the base merges into one prominent full tooth (= fang) that is followed by smaller denticles. The fang (first and largest denticle) of the genus Kettnerites resembles that of the genus Arabellites (maxillae I) but they differ in the sharply terminated posterior part of the base.

E m e n d e d d i a g n o s i s ( Šnajdr 1951, p. 260-261):

Jaw apparatus composed of one pair of mandibles and of seven asymmetrical maxillary plates with a pair of carriers.

Anteriorly the mandibles have a broad anterior part (frontal plate), which posteriorly terminates as elongated, gradually narrowing basal shafts. On the ventral side, in the anterior part is an oblique, raised plate, from which a carinate rim continues in the direction towards the farthest ends of the shafts.

The carriers are elongated, of conical shape, with an irregularly convex anterior margin, with distinctly bent lateral margins. In the original position they overlap somewhat anteriorly.

The forceps are asymmetrical, carinate, and attached to the carriers; anteriorly they have a characteristic hook, and their inner margin has for almost the whole of its length, minute conical denticles. On the upper side of the jaws, a strong rim runs along the anterior and outer lateral margins. In the posterior part of the right forceps is a curved basal plate of irregular shape, which fills the gap in the basal part of the forceps at the outer lateral margin.

The asymmetrical dental plates are characterised by their characteristic triangular shape and by a shank on the outer lateral margin, approximately at half the length of the jaw. The shape and number of denticles on the inner margin differs greatly.

The unpaired piece is also triangular, with some unequally long denticles on the inner lateral margin.

The paragnaths are also asymmetrical, with an approximately square shape, with a row of minute denticles on the inner margin of the jaw and with a distinctly thinning outer lateral margin.