Paläontologische Zeitschrift

, Volume 51, Issue 3–4, pp 271–287

A redescription of the Middle Cambrian wormAmiskwia sagittiformis Walcott from the Burgess Shale of British Columbia

  • S. Conway Morris
Article

Abstract

Amiskwia sagittiformis Walcott is redescribed on the basis of the five available specimens. The dorsoventrally compressed body consists of a head bearing a pair of prominent tentacles and a trunk with lateral and caudal fins. A gut with subterminal openings, cerebral ganglia, nerve cords, blood vessels and muscles have been identified with varying degrees of confidence. An active pelagic mode of life is considered probable. The rejection by earlier workers of this worm from the arrow-worms (Chaetognatha) is confirmed, but their identification of it as a nemertean (Nemertea) cannot be supported owing to the absence of critical data. The systematic position ofA. sagittiformis remains unresolved.

Zusammenfassung

Amiskwia sagittiformis Walcott wird auf der Basis von fünf erhältlichen Exemplaren neu beschrieben. Der dorsoventralisch komprimierte Körper besteht aus einem Kopf mit einem Paar hervorstehender Fühler und einem Rumpf mit Seiten- und Schwanzflossen. Ein Darm mit subterminalen Dffnungen sowie Gehirnganglien, Nervenstränge, Blutgefäße und Muskeln konnten mit variierendem Sicherheitsgrad identifiziert werden. Eine aktive pelagische Lebensform wird als wahrscheinlich angenommen. Die Abgrenzung dieses Wurms von den Pfeilwürmern (Chaetognatha), die in früheren Arbeiten unternommen wurde, wird bestätigt, aber deren Klassifizierung als Nemertinen (Nemertea) kann aufgrund fehlender kritischer Daten nicht aufrechterhalten werden. Die systematische Einordnung derA. sagittiformis bleibt weiterhin ungelost.

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Copyright information

© E. Schweizerbart’sche Verlagsbuchhandlung 1977

Authors and Affiliations

  • S. Conway Morris
    • 1
  1. 1.Sedgwick MuseumCambridgeEngland

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