Macro-photographic (A, B, D) and fluorescent (C) images of Cindarella eucalla. A Dorsal view of YKLP 17360. B Dorsal view of YKLP 17363a. C Close-up of hypostome in B. D Ventral view of YKLP 17373. Abbreviations: ant, antenna(e); ca, caeca; el, exopod lobe (shaft); Cn, Post-antenna cephalic appendage number; exo, exopod; ey, eye(s); gut, gut content/trace; hs, head shield; tn, tergite number. Scalebar: 1 cm in A and B, 2 mm in D, 1 mm in C. Figure 1—figure supplement 1. Macro-photographic images of Cindarella eucalla. A Dorsal view of YKLP 17363b. B Dorsal view of YKLP 17364. C Dorsal view of YKLP 17375. Abbreviations: ant, antenna(e); Cn, post-antenna cephalic appendage number; ey, eye(s); gut, gut content/trace; hs, head shiled; tn, tergite number; r, right; l, left. Scalebar: 5 mm.

Schematic diagram of eye movements in Cindarella eucalla. Gray area indicates head shield, dashed line indicates putative head shield, deep purple area indicates eye, doted area indicates putative eye in A and C. A Outline of head shield and eyes in three specimens of Cindarella eucalla (Left to right): YKLP 17371, YKLP 17368 and YKLP 17366. B Schematic diagram of eye movements in A. C Outline of head shield and eyes in two specimens of Cindarella eucalla (Left to right): YKLP 17365, YKLP 17368. D Schematic diagram of eye movements in A and C. Not to scale. Figure 2—figure supplement 1. Head shield and eyes of Cindarella eucalla. A YKLP 17366, Dorsal view. B YKLP 17368, dorsal view. C YKLP 17367, dorsal view. D YKLP 17365, dorsal view. E YKLP 17376, dorsal view. F YKLP 17373, dorsal view. G YKLP 17372, dorsal view. Scalebar: 2 mm in G, 5 mm in A, D and F, 1 cm in B, C and E. Figure 2—figure supplement 2. Outline of head shield (half) and eyes in Cindarella eucalla specimens. Gray area indicates head shield, dashed line indicates putative head shield, deep purple indicates eye, doted area indicates putative eye. A YKLP 17371. B YKLP 17368. C. YKLP 17366. D YKLP 17362 (flipped horizontal). E YKLP 17367. F YKLP 17376 (flipped horizontal). G YKLP 17365. H YKLP 17373. I YKLP 17372 (flipped horizontal). Not to scale.

Digital anatomy of Cindarella eucalla (YKLP 17369) based on X-ray tomographic data processed in Drishti v2.4. A YKLP 17369a, dorsal view. B YKLP 17369a, left antenna and eye, dorsal view. C overlap of head shield (in red) and trunk tergites (in cyan) within the dashed box in A. D YKLP 17369b, Ventral view, body and appendages digitally extracted from rocks. E Anterior sclerite and hypostome within the dashed box in D with the second and third left cephalic appendages romoved, ventral view (flipped horizontally). The dashed lines indicate two longitudinal sections in E1 and E2. E1–E2 two longitudinal sections (flipped horizontally) indicated in E. The arrowheads indicate separated sclerites posited anterior to first post-antennal appendage pair. Abbreviations: ann, antennal segment number; ant, antenna(e); ans, antennal scale; asc, anterior sclerite; Cn, post-antennal cephalic appendage number; exi, exite(s); ey, eye(s); hs, head shiled; tn, tergite number; Tn, trunk appendage number; l, left; r, right. Scalebar: 5 mm in A, 2 mm in D, 1 mm in B, 0.2 mm in E, no scalebar in C, E1 and E2. Figure 3—figure supplement 1. Macro-photographic (A and C) and fluorescent (B and D) images of Cindarella eucalla (YKLP 17369). A and B YKLP 17369a, dorsal view. C and D YKLP 17369b. Abbreviations: tn, tergite number. Scalebar: 5 mm.

Digital anatomy of Cindarella eucalla (YKLP 17369b) based on X-ray tomographic data processed in Drishti v2.4. A Dorsal view of the first right trunk appendage. B Dorsal view of the third left trunk appendage, red arrows indicate spines on terminal claw of endopods. C Dorsal view of the seventh left trunk appendage, red arrows indicate spines on terminal claw of endopods. D Ventral view of the eleventh right trunk appendage. E Dorsal view of left posterior trunk appendages. Abbreviations: el, exopod lobe; en, endopod; lm, lamella(e); exi, exite(s); hs, head shiled; pdn, endopod podomere number; pt, protopodite; st, seta(e); tc, terminal claw; tn, tergite number; Tn, trunk appendage number; l, left; r, right. Scalebar: 1 mm in A–E. Figure 4—figure supplement 1. Macro-photographic (A, C) and fluorescent (B, D) images of Cindarella eucalla (YKLP 17369). A YKLP 17374, dorsal view. B close-up of trunk appendages within the dashed box in A. C YKLP 17362, dorsal view. D close-up of a trunk exopod within the dashed box in C. Abbreviations: el, exopod lobe/shaft; ey, eye; hs, head shield; lm, lamella(e); Tn, trunk appendage number; tn, Tergite number; l, left; r, right. Scalebar: 1 cm in A, 5 mm in C, 2 mm in B, 1 mm in D.

Digital anatomy of Cindarella eucalla (YKLP 17370) based on X-ray tomographic data processed in Drishti v2.4. A Overview, ventral, with dorsal exoskeleton partially removed. B anterior structures beneath the head shield within the dashed box in A, with anterior sclerite, hypostome and mouth painted in different colours respectively. C Ventral view of the third left cephalic appendage. D Ventral view of the second and third right cephalic appendages, with the exopods and endopods painted in different colours. Abbreviations: ant, antenna(e); asp, axial spine(s); Cn, post-antennal cephalic appendage number; hy, hypostome; pdn, endopod podomere number; lm, lamella(e); pt, protopodite; sp, spine(s); tc, terminal claw; Tn, trunk appendage number;l, left; r, right. Scalebar: 2 mm in A and B, 1 mm in C, 0.5 mm in D.

Macro-photographic picture (A) and results from X-ray tomographic data processed in Drishti v2.4 (B, C), YKLP 17361. A Overview, dorsal. B Overview, ventral. C Ventral view of the second left trunk appendage. Abbreviations: ant, antenna(e); Cn, post-antennal cephalic appendage number; el, exopod lobe (shaft); ey, eye(s); gd, gut diverticula(e); hy, hypostome; pdn, endopod podomere number; pt, protopodite; sp, spine(s); tc, terminal claw; Tn, appendage number; tn, tergite number; l, left; r, right. Scalebar: 1 cm in A and B, 2 mm in C. Figure 6—figure supplement 1. Outline of trunk tergites and ventral segments (gut trace or appendage boundaries). A YKLP 17361. B YKLP 17362. C ELRC 18505. Abbreviations: tn, tergite number. Scalebar: not to scale.

Macro-photographic picture (A, C) and results from X-ray tomographic data processed in Drishti v2.4 (B, D). A Overview of YKLP 17370, dorsal view. B Dorsal (left) and ventral (right) views of the posterior trunk in A hide in the rock. C Overview of YKLP 17371, dorsal view. D Dorsal (left) and ventral (right) views of posterior trunk in C hide in the rock. Abbreviations: ant, antenna(e); anu?, putative anus; asp, axial spine(s); Cn, post-antennal cephalic appendage number; ey, eye(s); gut, gut content/trace; hs, head shield; psp, pleural spine(s); Tn, tergite number. Scalebar: 1 cm in C, 2 mm in A, 1 mm in B and D.

Three-dimensional Blender model of Cindarella eucalla. A Overview in dorsal view with the head shield transparent. B Overview in ventral view. C Biramous appendage in ventral view. D Biramous appendage in ventral view. E Last four trunk tergites with axial spines in antero-lateral oblique view. F Overview in lateral left view. Not to scale.

Results of parsimony and Bayesian phylogenetic analyses. All trees depict a strict consensus. Multiple species within the same genus are indicated as a single genus and marked in bold, Xandarellids are in blue, purple asterisks indicate Cindarella eucalla. A Equal weight parsimony, 159 most-parsimonious trees, 274 steps, consistency index (CI) = 0.391, retention index (RI) = 0.712). B Implied weight parsimony, k = 3, 4, 5, 281 steps, CI = 0.381, RI = 0.700. C Implied weight parsimony, k = 10, 40 most-parsimonious trees, 276 steps, CI = 0.388, RI = 0.709. D MrBayes. Setting: Mk model, four runs, 10 000 000 generations, 1/1000 sampling resulting in 10 000 samples, 25% burn-in resulting in 7500 samples retained. Figure 9—figure supplement 1. Strict consensus trees from parsimony analyses on Artiopoda showing common synapomorphies mapped. The numbers 0 to 92 below the branches represent 93 characters sequentially used for phylogenetic analysis. A Equal weight, 159 trees, CI=0.391, RI=0.712, 274steps. B Implied weight, k=3, 43 trees, CI=0.381, RI=0.700, 281 steps. C Implied weight, k=10, 40 trees, CI=0.388, RI=0.709, 276steps.

Macro-photographic images of Cindarella eucalla. A Dorsal view of YKLP 17363b. B Dorsal view of YKLP 17364. C Dorsal view of YKLP 17375. Abbreviations: ant, antenna(e); Cn, post-antenna cephalic appendage number; ey, eye(s); gut, gut content/trace; hs, head shiled; tn, tergite number; r, right; l, left. Scalebar: 5 mm.

Head shield and eyes of Cindarella eucalla. A YKLP 17366, Dorsal view. B YKLP 17368, dorsal view. C YKLP 17367, dorsal view. D YKLP 17365, dorsal view. E YKLP 17376, dorsal view. F YKLP 17373, dorsal view. G YKLP 17372, dorsal view. Scalebar: 2 mm in G, 5 mm in A, D and F, 1 cm in B, C and E.

Outline of head shield (half) and eyes in Cindarella eucalla specimens. Gray area indicates head shield, dashed line indicates putative head shield, deep purple indicates eye, doted area indicates putative eye. A YKLP 17371. B YKLP 17368. C. YKLP 17366. D YKLP 17362 (flipped horizontal). E YKLP 17367. F YKLP 17376 (flipped horizontal). G YKLP 17365. H YKLP 17373. I YKLP 17372 (flipped horizontal). Not to scale.

Macro-photographic (A and C) and fluorescent (B and D) images of Cindarella eucalla (YKLP 17369). A and B YKLP 17369a, dorsal view. C and D YKLP 17369b. Abbreviations: tn, tergite number. Scalebar: 5 mm.

Macro-photographic (A, C) and fluorescent (B, D) images of Cindarella eucalla (YKLP 17369). A YKLP 17374, dorsal view. B close-up of trunk appendages within the dashed box in A. C YKLP 17362, dorsal view. D close-up of a trunk exopod within the dashed box in C. Abbreviations: el, exopod lobe/shaft; ey, eye; hs, head shield; lm, lamella(e); Tn, trunk appendage number; tn, Tergite number; l, left; r, right. Scalebar: 1 cm in A, 5 mm in C, 2 mm in B, 1 mm in D.

Outline of trunk tergites and ventral segments (gut trace or appendage boundaries). A YKLP 17361. B YKLP 17362. C ELRC 18505. Abbreviations: tn, tergite number. Scalebar: not to scale.

Strict consensus trees from parsimony analyses on Artiopoda showing common synapomorphies mapped. The numbers 0 to 92 below the branches represent 93 characters sequentially used for phylogenetic analysis. A Equal weight, 159 trees, CI=0.391, RI=0.712, 274steps. B Implied weight, k=3, 43 trees, CI=0.381, RI=0.700, 281 steps. C Implied weight, k=10, 40 trees, CI=0.388, RI=0.709, 276steps.