Figure 4: Alignment and homology of anterior appendages in the lobopodian O. ferox and among extant panarthropods.

Homologous appendages are depicted by corresponding colour. Vertical dotted lines indicate segmental borders. Black and checked ovals represent ocelli and compound eyes, respectively. Alignment of head segments in tardigrades is based on the assumption of serial homology of the stylet with distal leg portions²⁰. Note that segmental identity and homology of the arthropod labrum is discussed controversially^30,31,33,40. Dark-grey hatched area in the diagram on mandibulate arthropods indicates segments that do not contribute to adult mouth formation. Note that non-homologous segments and structures are involved in adult mouth apparatuses in O. ferox and different groups of extant panarthropods. af, antenniform appendage; at, antenna; at1, first antenna; at2, second antenna (indicated by a dotted line, as it occurs only in crustaceans); ch, chelicera; ic, intercalary segment (limbless in myriapods and hexapods); jw, jaw; lb, labrum (question mark highlights the uncertain segmental identity and homology of this structure); le, walking limbs/lobopods; md, mandible; mx, maxilla; pb, proboscis; pp, pedipalp; sp, slime papilla; st, stylet.