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Updated: May 19, 2026
06:27
Assaying Predatory Feeding Behaviors in Pristionchus and Other Nematodes
Published on: September 4, 2016
A non-feeding pilidium with apparent prototroch and telotroch
Svetlana A Maslakova1, George von Dassow
1Oregon Institute of Marine Biology, Oregon Institute of Marine Biology, Charleston, Oregon. svetlana@uoregon.edu
Summary
Researchers discovered a novel, reduced pilidium larva in nemerteans that resembles a trochophore. This finding challenges the understanding of invertebrate larval evolution and the conserved nature of the trochophore form.
Area of Science:
- Marine Biology
- Developmental Biology
- Evolutionary Biology
Background:
- The nemertean pilidium larva is typically long-lived and planktotrophic, making it difficult to compare with other invertebrate larval forms.
- The evolutionary origins and homologies of invertebrate larvae, particularly the trochophore, remain a significant area of research.
Purpose of the Study:
- To describe a novel, reduced, lecithotrophic pilidium larva that superficially resembles a trochophore.
- To investigate the metamorphosis of this unique larval form and its phylogenetic placement.
Main Methods:
- Morphological observation of the pilidium-like larva and its metamorphosis.
- Molecular phylogenetic analysis using COI and 16S rRNA gene sequences.
Main Results:
- A reduced, lecithotrophic pilidium larva was identified, exhibiting catastrophic metamorphosis with self-devouring.
- Phylogenetic analysis revealed the larva belongs to an undescribed lineiform nemertean species.
- The larva's morphology and metamorphosis challenge existing notions of larval ground plans.
Conclusions:
- The discovery of this novel pilidium larva provides new insights into nemertean larval diversity and evolution.
- This finding contributes to the ongoing debate on whether the trochophore is a conserved larval ground plan or a result of convergent evolution.
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