Why is it difficult to place marella in any o the subphyla of living anthropods?

Marella, an extinct genus from the Cambrian period, presents challenges in classification due to its unique morphological features that do not align neatly with the characteristics of existing subphyla of arthropods. Its body plan exhibits a combination of traits, including a flattened, lobed structure and segmented body, which complicates its placement within the traditional categories of arthropods such as crustaceans, hexapods, or myriapods. Additionally, the lack of well-preserved specimens makes it difficult to ascertain its ecological role and evolutionary relationships, leading to ongoing debates among paleontologists regarding its true classification within the arthropod lineage.