| Genus Rakvereprion Mierzejewski, 1978 |
| Type species: Staurocephalites? balticus Eisenack, 1975 |
| Diagnosis: " Jaw apparatus of placognath type with symmetric posterior part consisting of right and left MI, basal and laeobasal plates. Anterior part of the apparatus unknown. MIr almost straight, slightly bent outwards in its anterior part, elongate. Basal plate elongate, compressed laterally, equal in length to MIr, adhering to its outer margin. MIl and laeobasal plate forming mirror images of MIr and basal plate." (Mierzejewski 1978, p. 279). |
| Remarks. -The type species of the genus has been tentatively assigned by Eisenack (1975) to the genus Staurocephalites Hinde, 1879. Actually, however, the latter name is nomen dubium. |
| Kielan-Jaworowska (1966) mentioned an undescribed apparatus with its MI resembling MI and MII of Xanioprion Kielan-Jaworowska, attached one to the other; the apparatus was assigned to Xanioprion sp. One may claim that Rakvereprion is closely related to Xanioprion, the main differences being in the wholeness of the apparatus elements in the former genus, while they are split transversally in the latter one. In fact, Rakvereprion appears intermediate between the Mochtyellidae and Xanioprionidae. |
| References: |
| Eisenack, A. 1975. Beiträge zur Anneliden-Forschung. - Neues Jahrbuch für Geologie und Paläontologie Abhandlunge, Monatshefte, 150 (2), 227-252. |
| Kielan-Jaworowska, Z. 1966. Polychaete jaw apparatuses from the Ordovician and Silurian of Poland and a comparison with modern forms. - Palaeontologia Polonica 16, 1-152. |
| Mierzejewski, P. 1978. New placognath Eunicida from the Ordovician and Silurian of Poland. - Acta Geologica Polonica 28, 2, 273-281. |
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