The Late Silurian anaspid genus Rhyncholepis from Oesel, Estonia, and Ringerike, Norway

"Re-examination and further preparation of the original material of the Silurian anaspid Saarolepis oeselensis (Robertson) from the Ludlovian Paadla Formation of Oesel, Estonia, has led to the discovery of an almost complete and uncrushed head of this species. In the structure of its cranial and ventral (gular) shields the Oesel form closely resembles the well-known Rhyncholepis parvulus Kiaer from the Upper Silurian of Ringerike, southern Norway, and it must now be assigned to that genus, with the suppression of Saarolepis (Robertson). There are sufficient differences of specific importance between the forms from Norway and from Oesel to justify the retention of Rhyncholepis oeselensis (Robertson) as a separate species, the second of this genus to be recognized. Details are also given of the discovery of well-developed, paired, ventrolateral finfolds in the Norwegian species, R. parvulus Kiaer, reinforcing earlier evidence that the presence of such fins is the rule rather than the exception in anaspids"