Fig. 4 Length–maximum width plot of Belonechitina sp. 2 (circles), Belonechitina micracantha (triangles) and Belonechitina sp. 1 (crosses).

; 2. Cyathochitina campanulaeformis ; 3. Lagenochitina obeligis ; 4. Conochitina cf. poumoti ; 5. Eremochitina brevis ; 6. Eremochitina cf. brevis ; 7. Angochitina persianense sp. nov.; 8. Desmochitina ornensis ; 9. Belonechitina henryi ; 10. Belonechitina punctata ; 11. Conochitina cf

Plate 4. Figures 1, 5; 2, 6; 9, 13. Belonechitina robusta (Eisenack 1959 ; sample MG-20); Figs. 3, 7; 4, 8. Belonechitina bifurcaspina sp. nov. (sample MG-111); Figs. 10, 14; 11, 15; 12, 16; 17, 18. Belonechitina tenuicomata Paris et al., 2015 (sample MG-165); Fig. 19. Conochitina

Plate 5. Figures 1, 5, 9; 2, 6. Belonechitina capitata Eisenack 1962 ; figures 3, 7; 4, 8; 10, 14;11, 15; 12, 16. Belonechitina micracantha (Eisenack 1931 ); figures 13; 17, 21; 19, 23. Pistillachitina pistillifrons Eisenack 1939 ; figures 18, 22. Cyathochitina calix (Eisenack 1931

Plate 7 (facingpage): Chitinozoans from the Saih Nihayda Formation, Baqlah-1 (a, d-e, g-h) and an unnamed well (b-c, f, i-j) Oman. (a) Belonechitina gr. micracantha . 9231.17’. IGR 70993 (L41/4). (b) Velatachitina nebulosa . Cuttings from 9547.22’, unnamed well. IGR 70909 (K45). uncommon

Plate 5. 1–3. Belonechitina wesenbergensis brevis (Eisenack, 1959). From YYZ-01 (3) and YYZ-02 (1–2). 4–5. Eisenackitina inconspicua Vandenbroucke 2004 . From YYZ-02. 6. Angochitina sp. 1. From YYZ-06. 7–9. Belonechitina micracantha typica (Eisenack, 1959, emend. Paris 1981 ). From YYZ

Plate 2. Figures 1, 2; 13, 17. Belonechitina robusta (Eisenack 1959 ; sample MG-11); Fig. 3. Lagenochitina baltica Eisenack, 1931 (sample MG-33); Fig. 4. Calpichitina lenticularis (Bouché 1965 ; sample MG-11); Figs. 5, 9. Conochitina elegans Eisenack, 1931 (sample MG-20); Figs. 6

Plate 6. Figures 1, 4, 8; 9, 13. Belonechitina robusta (Eisenack 1959 ; sample MG-20); Figs. 2, 6; 10, 14. Belonechitina micracantha (Eisenack 1931 ) emend. Paris 1981 (sample MG-168); Figs. 3, 7. Armoricochitina nigerica (Bouché 1965 ; sample MG-151); Figs. 5, 16. Calpichitina

species names relate to those at the bottom of the figure). 1. Eremochitina brevis ; 2. Cyathochitina varennensis ; 3. Desmochitina minor ; 4. Cyathochitina campanulaeformis ; 5. Desmochitina ornensis ; 6. Belonechitina henryi ; 7. Cyathochitina protocalix ; 8. Cyathochitina calix ; 9

Plate 1. Main chitinozoan specimens: 1— Belonechitina micracantha typica (Eisenack, 1931). GSC 133469, sample 2007-PR-5 (Institut national de la recherche scientifique [INRS] 31626). Total length: 270 μm; maximum diameter: 91μm. 2— Belonechitna micracantha forma A. Geological Survey of Canada

Explanation of Plate 1 figs 1, 2 . Belonechitina tuberculata (scale bars 10 μm): 1, 310 × 120 incomplete specimen (sample NJ352) – 1a, detail of 1; 2, 350 × 110 incomplete specimen (sample NJ355) – 2a, detail of 2. figs 3, 4 . Laufeldochitina sp. A aff. striata Grahn et al

Explanation of Plate 2 figs 1, 2 . Belonechitina sp. 1: 1, 480 × 130 × 130 (sample NJ328); 2, 540 × 110 × 110 (sample NJ328). figs 3, 4 . Belonechitina sp. 2 (scale bars 10 μm): 3, 390 × 100 × 85 (sample NJ355) – 3a, detail of 3; 4, 610 × 110 × 85 (sample NJ355) – 4a, detail

Figure 16. Silurian chitinozoans from the Aizpute-41 core, Latvia. (a) Belonechitina postrobusta (Nestor); Ch 551/11924; 977.95–978.10 m; × 220. (b) Cyathochitina campanulaeformis (Eisenack); Ch 549/12103; 982.60–982.70 m; × 200. (c) Cyathochitina cf. kuckersiana (Eisenack); Ch 552/11924

Fig. 8. Diagram showing the length/width ratio (L/Dp) for Belonechitina nevillensis n. sp.

Fig. 9. Diagram showing the length/width ratio (L/Dp) for Belonechitina uniformipunctata n. sp.

Fig. 5 Chitinozoans from the lower part of the Ardwell Farm Formation at Pinmerry. ( a ) Belonechitina hirsuta (170 × 70). ( b ) Belonechitina ? robusta (190 × 73). ( c ) Hercochitina sp. (210 × 70). ( d ) Hercochitina sp. (220 × 70). ( e ) Conochitina sp. (360 × 100). All measurements