Extended Data Fig. 2: Additional arthropods from the Castle Bank Fauna.

a–d, stem-group xiphosuran from level A0 with detail view of anterior interpretative diagram (b, excluding whip-like posterior that may be an overlain structure), including robust anterior appendages (ap) (enlarged in c), prosoma (shaded, slightly rotated) with eye ridges (ey), mesosoma (meso), segmented metasoma (meta) and base of telson (tel); note also polygonal sculpture on prosoma, visible in d, the counterpart, with second eye ridge arrowed (NMW.2021.3 G.9); e–f, elongate arthropod with cephalocarid-like characters (NMW.2021.3 G.14) with interpretative drawing (based also on additional lighting variations) distinguishing cephalon (ce), thorax with ten segments (th1–10), abdomen with approximately 12 segments (ab1–12) and forked telson (t); g, h, hexapod-like arthropod (as Fig. 1b) with enhanced contrast and interpretative diagram (h), highlighting body regions, three visible limbs (numbered, and in different colours), possible superimposed antenna (ant?) and possible mandible (m?) (NMW.2021.3 G.11); i, j, pair of barnacles, the right attached to the left, with explanatory drawing (ped: peduncle in anterior/posterior view, and broader in lateral view; car: carina; tg: tergum; sc: scutum; ci: cirri) (NMW.2021.3 G.66); k, bivalved arthropod with robust frontal appendages, tail fan and posteriorly spined carapace (NMW.2021.3G.13). Scale bars 1 mm.