Arthropods arose suddenly (Talk.Origins)
Source: No source given.
CreationWiki response: (Talk.Origins quotes in blue)
1. Anomalocaris, from the Cambrian and Precambrian, has a pair of segmented appendages, indicating arthropod affinities, but it also seems to have lobopod legs. The related Opabinia also apparently had lobopod legs. Other rare Cambrian and Precambrian fossils show some promise of shedding more light on relationships. For example, Spriggina, another Precambrian animal, has a head shield similar to trilobites.
- A comparison of Anomalocari and arthropods; particularly millipedes; strongly suggest that Anomalocaris should be classified as an Arthropod. Most likely Anomalocaris was simply an aquatic Arthropod. Their lobopod legs are a mosaic trait, but nothing objectively transitional.
- A comparison of Opabinia and arthropods strongly suggest that Opabinia should be classified as an Arthropod. Most likely Opabinia was simply an aquatic Arthropod. Their lobopod legs are a mosaic trait, but nothing objectively transitional.
- Spriggina had more than just a trilobite's head shield but the same basic body structure. The main difference seems to be that Spriggina had a longer body. Most likely Spriggina were just long trilobites.
- Reference: Vendian Animals: Spriggina
All three so-called transitional types seem to be arthropods, two of which have a single mosaic trait. So thank you Talk.Origins for proving this claim 100% correct.