Silurian atrypide brachiopods from Yass, New South Wales

Figures & data

Fig. 1. Chart showing the stratigraphic distribution of atrypide taxa in the Yass Syncline. Dashed lines represent intervals of non-occurrence (those extending from the bottom of the chart are of taxa also known from Wenlock levels in the Canberra-Yass region). Arrows indicate uncertainty in range, usually because of poorly located early collections. The single very poorly located specimen tentatively assigned to G. (Gracianella) is not shown. Symbols for members within formations are (in ascending order): OCS — O'Briens Creek Sandstone, CL — Cliftonwood Limestone, EL — Euralie Limestone, ECS — Excursion Creek Sandstone, GRL — Gums Road Limestone, TS — Tullerah Sandstone, BL — Bowspring Limestone, BS — Barrandella Shale, HL — Hume Limestone, YS — Yarwood Siltstone, RHM — Rainbow Hill Member.

Fig. 2. Atrypa sp. cf. A. dzwinogrodensis Kozłowski, 1929. A, AMF29280, juvenile shell. B, AMF29279, clearly showing abrupt change in rib size and spacing. C, AMF29198, figured Mitchell & Dun 1920, pl. XV, fig. 7. D, AMF29199, figured Mitchell & Dun, pl. XV, fig. 6. A & B labelled ‘Silverdale’, Silverdale Fm or basal Black Bog Shale; C & D labelled ‘near Silverdale’, Bowspring Limestone Member. Letters d , l , v , p , a , here and in subsequent Figures, indicate the same shell in dorsal, lateral, ventral, posterior and anterior views. All ×2.

Fig. 3. Atrypa sp. cf. A. dzwinogrodensis Kozłowski, 1929. Plots of Ls and Ts Against Ws, and the ratio L(Wmax)/Ls against Ls.

Fig. 4. Atrypa sp. cf. A. dzwinogrodensis Kozłowski, 1929. A, AMF29281, large shell with partly preserved marginal flange, figured Mitchell & Dun 1920, pl. XVI, fig. 20. B, AMF129699, incomplete juvenile ventral internal mould. C, D, AMF28675, dorsal internal mould in dorsal and posterior views. A labelled ‘Silverdale’, B – D ‘Hattons Corner’, Silverdale Fm or basal Black Bog Shale. Letters d , l , v , p , a  — dorsal, lateral, ventral, posterior, and anterior views. All ×2.

Fig. 5. Reticulatrypa pulchra (Mitchell & Dun, 1920). A, AMF29353, lectotype, figured by Mitchell & Dun (1920, pl. XVI, figs 14, 15). B, ANU46437, latex replica of ventral exterior. C, AMF29354, paralectotype, figured by Mitchell & Dun 1920, pl. XIV, fig. 19). D, E, AMF27790, ventral external mould showing rib structure. F, AMF29352, paralectotype, figured by Mitchell & Dun (1920, pl. XVI, fig. 15). G, ANU46435, latex replica of juvenile dorsal interior. H, CPC38992, ventral internal mould. I, J, AMF25836, dorsal internal mould and latex replica. A, C, F labelled ‘Limestone Creek near Silverdale’, Hume Limestone Member or basal Black Bog Shale; B, loc. KC47, H, loc. GOU46, Yarwood Siltstone Member; D, E labelled ‘near Bowning’, probably basal Black Bog Shale; G, loc. KF, I, J labelled ‘Hattons Corner, LTB’, lower Black Bog Shale. Letters d , l , v , p , a  — dorsal, lateral, ventral, posterior, and anterior views. A, C, D, F, H – J ×2, B, G ×4, E ×5.

Fig. 6. Reticulatrypa pulchra (Mitchell & Dun, 1920). Plots of Ls and Ts against Ws, and the ratio L(Wmax)/Ls against Ls.

Fig. 7. Atrypina (Atrypina) sp. cf. A. latesinuata Rong & Yang, 1974. A, B, ANU46440, latex replicas of ventral and dorsal exteriors. C, ANU46444, latex replica of dorsal exterior. D, E, ANU46439, latex replicas of ventral exterior and interior. A – C loc. KE, D – E loc. KC48; Yarwood Siltstone Member. All ×8.

Fig. 8. Atrypina (Atrypina) sp. cf. A. latesinuata Rong & Yang, 1974. Plot of Ls against Ws, including (crosses) data for A. (A.) latesinuata from Rong & Yang 1981.

Fig. 9. A – D, Gracianella (Gracianella) kausi kausi (Strusz, 1982). A, B, CPC20518, holotype, in dorsal and ventral views. C, CPC20473, paratype, latex replica of ventral interior. D, CPC20475, paratype, latex replica of dorsal interior. Walker Volcanics, Canberra. E – O, Gracianella (Gracianella) kausi yassensis n.ssp. E, ANU15607, paratype, latex replica of ventral interior. F, G, ANU 15606, holotype, latex replica of ventral interior in dorsal and oblique views. H, I, ANU46449, paratype, latex replicas of dorsal exterior and interior. J, ANU46454, paratype, latex replica of dorsal interior. K, ANU46446, paratype, latex replica of dorsal exterior. L, ANU15603, paratype, latex replica of dorsal interior. E – L, loc. KC, Yarwood Siltstone Member. M, CPC39015, dorsal internal mould. N, ANU46459, latex replica of ventral interior. O, ANU46462, latex replica of dorsal interior. M – O, loc. KF (GOU52), lower Black Bog Shale. All ×8.

Fig. 10. Gracianella (Gracianella) kausi (Strusz, 1982). Plots of Ls and Ld against Ws for subspecies kausi (dots) and yassensis (crosses).

Fig. 11. Gracianella (Gracianella)? sp. AMF131514 in dorsal, lateral, ventral, posterior and anterior aspects, ×8. Hattons Corner near Yass, horizon uncertain.

Fig. 12. Gracianella (Sublepida)? sp. A, B, ANU46465, latex replicas of ventral exterior and interior. C, ANU46464, latex replica of ventral interior. Loc. KE, Yarwood Siltstone Member. All ×8.

Fig. 13. Gen. et sp. indet. cf. Becscia. AMF129835, ventral internal mould and latex replica, ×8. ‘Bowning’, probably Rainbow Hill Member.

Fig. 14. Spirigerina mitchelli sp. nov. A, B, AMF28570, ventral internal mould and latex replica. C, CPC39028, partly silicified shell in dorsal view. D, paratype AMF129717, juvenile shell. E, paratype AMF29173, figured by Mitchell & Dun (1920, pl. XVI, fig. 2). F, paratype AMF29171, figured Mitchell & Dun pl. XVI, fig. 3. G, holotype AMF51717, figured by Mitchell & Dun (1920, pl. XVI, fig. 4). H, paratype AMF51716, figured by Mitchell & Dun (1920, pl. XVI, fig. 1). I, paratype AMF29172, figured by Mitchell & Dun (1920, pl. XV, fig. 16). J, paratype AMF29174, figured by Mitchell & Dun (1920, pl. XVI, fig. 5). K, ANU46466, latex replica of ventral interior. L – N, ANU9720, latex replica of ventral interior in dorsal and anterodorsal views. A, B labelled ‘Bowning’, horizon uncertain; C, loc. GOU48, Yass Fm; D – J labelled ‘Limestone Creek, east of Bowning’ lower Black Bog Shale; K – N, loc. KC48, Yarwood Siltstone Member. Letters d , l , v , p , a —dorsal, lateral, ventral, posterior, and anterior views. A – J, L ×2, K, M, N ×4.

Fig. 15. Spirigerina mitchelli sp. nov. Plots of Ls against Ws and Ts against Ls.

Fig. 16. Atrypoidea (Atrypoidea) australis (Dun, 1904). A, MMF4014, lectotype, Molong (shell not whitened). B, AMF29197, lectotype of Atrypoidea angusta Mitchell & Dun, 1920, labelled ‘Gurnett's’, Yass district (locality and horizon unknown). Letters d , l , v , p , a  — dorsal, lateral, ventral, posterior, and anterior views. Both ×1.5.

Fig. 17. Atrypoidea (Atrypoidea) australis (Dun, 1904). A – G show development and variability during growth. A, AMF129757. B, AMF129771. C, AMF129758. D, AMF129770. E, AMF29183, figured by Mitchell & Dun (1920, pl. XIV, figs 1 – 2). F AMF29184, figured by Mitchell & Dun (1920, pl. XIV, figs 3 – 4). G, AMF29186, figured by Mitchell & Dun (1920, pl. XIV, fig. 18). H, paralectotype AMF46736 (dorsal valve and ventral umbo heavily eroded), figured by Dun (1904, fig. 3e). I, CPC24009, figured by Strusz (1984, fig. 14). J, CPC39038. K, L, ANU9736, latex replicas of ventral exterior and interior. M, ANU15626, latex replica of dorsal interior. N, ANU15609, latex replica of dorsal interior. O, P, ANU9735, latex replica of ventral interior in dorsal and anterodorsal views, showing strongly developed vascular imprints. A-E, H Molong, Molong Limestone; G, Hattons Corner, Silverdale Fm?; I, J, loc. GOU49, Yass Fm.; K – N, loc. KC21, Yarwood Siltstone Member; O, P, loc. KC51, upper Black Bog Shale. Letters d , l , v , p , a  — dorsal, lateral, ventral, posterior, and anterior views. A – H, J – L, O – P ×1.5; I ×6; M, N ×4.

Fig. 18. Atrypoidea (Atrypoidea) australis (Dun, 1904). A, AMF29200, figured by Mitchell & Dun (1920, pl. XIV, fig. 27 as A. angusta). B, AMF29188, figured by Mitchell & Dun (1929, pl. XIV, fig. 14 as A. australis). C, AMF17432, labelled A. australis. D, AMF14215, labelled A. australis. A – C, Hattons Corner, Silverdale Fm?; D, Glenbower, Glenbower Fm. Letters d , l , v , p , a  — dorsal, lateral, ventral, posterior, and anterior views. All ×1.5.

Fig. 19. Atrypoidea (Atrypoidea) australis (Dun, 1904). A, AMF29185, figured Mitchell & Dun 1920, pl. XIV, fig. 29 as A. angusta. B, AMF29196, figured by Mitchell & Dun (1920, pl. XIV, figs 25 – 26 as A. angusta). C, AMF29195, figured by Mitchell & Dun (1920, pl. XIV, fig. 24 as A. angusta). D, AMF29193, figured by Mitchell & Dun (1920, pl. XIV, figs 8, 12 as A. australis and fig. 23 as A. angusta). E, AMF29192, figured by Mitchell & Dun (1920, pl. XIV, figs 5 –  7 as A. australis). All Molong Limestone. Letters d , l , v , a  — dorsal, lateral, ventral, and anterior views. All ×1.5.

Fig. 20. Atrypoidea (Atrypoidea) australis (Dun, 1904). Plots of Ls, and the ratios Ls/Ws, CM/Ws against Ws. Dots indicate specimens from the Molong Limestone, crosses those from the late Wenlock of the Canberra-Yass region, x for specimens from the Ludlow of Yass. an — specimens previously identified ad A. angusta (an* — lectotype); au* — lectotype, A. australis.

Fig. 21. Atrypoidea (Atrypoidea) australis (Dun, 1904). Plots against Ls of the ratios Ts/Ls, L(Wmax)/Ls, and ADAC/Ls. Symbols as in Fig. 20.

Fig. 22. Meifodia? sp. cf. M. lenticulata (Philip, 1960). A, MMF27958J, latex replica of ventral exterior. B, C, MMF27995, ventral internal mould and latex replica. D, MMF27994B, latex replica of ventral interior. E, F, MMF27993, dorsal internal mould and latex replica. G, MMF27957I, ventral internal mould. H, MMF27958, latex replicas of adjacent ventral exteriors. I, ANU46479, latex replica of ventral interior. J, MMF27981, latex replica of dorsal interior. K, L, ANU46480, latex replica of ventral interior. M, MMF27973B, latex replica of dorsal interior. A – G, I – K, M ×4; H, L ×2.

Fig. 23. Meifodia? sp. cf. M. lenticulata (Philip, 1960). Plot of Ls against Ws for Devonian M. lenticulata from Victoria (crosses), Manildra NSW (x) and Wellington NSW (o), and Silurian M. sp. cf. M. lenticulata from Yass (dots).

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