Organism · Animals
Louisella pedunculata
Source time context (not species duration) · ≈ 539–487 Ma
Inferred life reconstruction
Louisella pedunculata
Overview
Louisella pedunculata is a Cambrian worm with an eversible proboscis in front of a ringed trunk. Rows of small projections are described on the trunk. Its overall outline and several surface structures can be examined together.[1][2]
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Key facts
A museum caption for one specimen gives its length as 30 cm. Repeated small rings and projections extend along a long body outline.[1]
Time and place
Louisella pedunculata is known from the Walcott Quarry on Fossil Ridge. This is Middle Cambrian material from a locality in present-day British Columbia, Canada. The entire Cambrian spanned approximately 540–490 million years ago.[1][4][5][6]
The time range describes source context, not the complete duration of this species.
Size, form and skeleton
Rings and two rows of papilla-like projections are described on the trunk. A toothed proboscis lies at the front, while the rear end is described as lacking spines. Proboscis, trunk, and rear end can be read separately in sequence.[1][2]
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Habitat and reproduction
How were small surface projections arranged alongside the rings? Comparative research explains that long, slender projections on the ventral rear trunk do not correspond one-to-one with trunk rings. Comparing these two repeated structures is rewarding.[3]
Fossil discovery
The abstract of a 1977 study of fossil priapulids and a museum account describe two rows of trunk projections. Later comparative research addressed their positions and relationship to the rings. These studies divided the repeated structures of one body in different ways.[1][2][3]
References
- The Burgess Shale: Louisella pedunculata
- Conway Morris (1977) — A study of fossil priapulids
- Comparative study by Shi et al. — Trunk projections of Louisella
- International Commission on Stratigraphy (2024) — Geological time chart
- Royal Ontario Museum — The Burgess Shale locality today
- Royal Ontario Museum — Waptia fieldensis
- Paleobiology Database — Age of fossil-bearing strata of Selkirkia
- Royal Ontario Museum — Selkirkia columbia
Research questions
What changes when rings and small projections are followed separately? Markings surrounding the trunk and longitudinal rows of projections show different arrangements. This observation seeks differences between similarly repeated structures.[1][3]
Observation
Move your gaze from the front proboscis to the ringed trunk. Examining the two rows of small projections and the rear end in sequence reveals the front-to-back and surface organization of the long body.[1][2]
Related organisms
Selkirkia columbiaAnimalsSource time context (not species duration) · ≈ 510 MaTubes and proboscises of Cambrian worms
Explore the different records of bodies and time preserved by these two organisms. Louisella pedunculata is a Cambrian worm with an eversible proboscis in front of a ringed trunk. Rows of small projections are described on the trunk. It is known from the Walcott Quarry on Fossil Ridge, a Middle Cambrian locality in present-day British Columbia, Canada. Selkirkia columbia is a Cambrian worm whose body lies inside a tube open at both ends. Its anterior region and proboscis extend toward the front opening. Its specimens USNM 57624 and GSC 45330b come from the Walcott Quarry on Fossil Ridge in present-day British Columbia, Canada.