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Xenognath type of polychaete jaw apparatuses

Piotr Mierzejewski & Grażyna Mierzejewska

Acta Palaeontologica Polonica 1975, 20, 3, 437-444
[abstract, p. 437]
A new type of ?eunicid jaw apparatuses designated xenognath is described; it differs from previously known jaw apparatuses in having the denticulated ridges in compound jaws perpendicular to apparatus axis. It includes the Ordovician genus Archaeoprion nov., assigned to a new family Archaeoprionidae.
Archaeoprion quadricristatus Mierzejewski & Mierzejewska, 1975
Nearly complete jaw apparatus devoid of ridges IV; venral view of the right jaw and lateral view of the left one.
Specimen derived from the erratic boulder (Baltic coast, Caradoc).
      Diagnosis (p. 441) of Archaeoprion:

Almost triangular, plate-like compound jaws. Each jaw with four denticulated ridges. Denticulated ridge I lowermost, sometimes smooth. Denticulated ridge IV with chisel teeth. Pseudocarrier delicate, longer than jaws.
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Dimensions of the holotype: lenght 0.355 mm, width 0.178 mm.
Archaeoprion quadricristatus
left compound jaw
right compund jaw
Dorsal view of the xenognath jaws apparatus
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