Article,
A giant stem-group chaetognath
Affiliations
- [1] Korea Polar Res Inst, Div Earth Sci, Incheon 21990, South Korea [NORA names: South Korea; Asia, East; OECD];
- [2] Univ Sci & Technol, 217 Gajeong Ro, Daejeon 34113, South Korea [NORA names: South Korea; Asia, East; OECD];
- [3] British Geol Survey, Nicker Hill, Keyworth NG12 5GG, England [NORA names: United Kingdom; Europe, Non-EU; OECD];
- [4] British Geol Survey, Nicker Hill, Keyworth NG12 5GG, England [NORA names: United Kingdom; Europe, Non-EU; OECD];
- [5] British Geol Survey, Nicker Hill, Keyworth NG12 5GG, England [NORA names: United Kingdom; Europe, Non-EU; OECD];
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Abstract
Chaetognaths, with their characteristic grasping spines, are the oldest known pelagic predators, found in the lowest Cambrian (Terreneuvian). Here, we describe a large stem chaetognath, Timorebestia koprii gen. et sp. nov., from the lower Cambrian Sirius Passet Lagerstatte, which exhibits lateral and caudal fins, a distinct head region with long antennae and a jaw apparatus similar to Amiskwia sagittiformis. Amiskwia has previously been interpreted as a total-group chaetognathiferan, as either a stem-chaetognath or gnathostomulid. We show that T. koprii shares a ventral ganglion with chaetognaths to the exclusion of other animal groups, firmly placing these fossils on the chaetognath stem. The large size (up to 30 cm) and gut contents in T. koprii suggest that early chaetognaths occupied a higher trophic position in pelagic food chains than today.