Remopleurididae Hawle & Corda, 1847

Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed’s Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, Zootaxa 5162 (4), pp. 301-356 : 328

Family Remopleurididae Hawle & Corda, 1847

Remopleuridid gen. et sp. indet.

Figs 8.7 , 10

1917 Remopleurides aff. latus Olin ; Reed, p. 41, pl. 6, figs 9,10.

Material. Cranidium, Fig. 8.7 ( Reed, 1917, pl. 6, fig. 9), GSI 11884 ; free cheek, Fig. 8.10 (Reed, pl. 6, fig. 10), GSI 11885 ; both specimens from the Shihtien Formation (Darriwilian) at Pupiao, western Yunnan.

Discussion. Reed (1917, p. 41) compared this species with one from the Chasmops limestone of Norway. Reed’s illustration of the cranidium shows the usual thin, arched glabellar furrows of remopleuridids; the cast figured here taken from the mould does not show such furrows, which are therefore probably visible only on the internal mould. We assume following Reed that the free cheek belongs with the cranidium, although the eye seems to be deeper than usual, and its inner profile does not closely match that of the palpebral lobes on the cranidium. However, the latter could be transversely extended through modest distortion. The number of remopleuridid genera in China has been increased as the former Remopleurides sensu lato has been subdivided. Zhou et al. (2016) recognised Hexacopyge and Disloboaspis alongside Remopleurides itself, in the Pagoda Formation, for example. Details of the hypostome are crucial to discriminate these clades, and since that feature is lacking in Reed’s collection it must remain in open nomenclature.

Figures

FIGURE 8. (1–6) Birmanites yunnanensis (Reed) from the Shihtien Formation (Darriwilian), Pupiao, Baoshan Prefecture, western Yunnan, China. 1. Librigena (original of Reed 1917, pl. 7, fig. 3), GSI 11892. 2. Pygidium (original of Reed 1917, pl. 7, fig. 6), GSI 11895. 3. Pygidium (original of Reed 1917, pl. 7, fig. 8), GSI 11897. 4. Librigena (original of Reed 1917, pl. 7, fig. 5), GSI 11894. 5. Articulated specimen (original of Reed 1917, pl. 6, fig. 12), GSI 11887. 6. Cephalon (original of Reed 1917, pl. 6, fig. 14), GSI 11889. (7, 10) Remopleuriidae gen. et sp. indet. (Reed) from the Shihtien Formation (Darriwilian), Pupiao, Baoshan Prefecture, western Yunnan, China. 7. Cranidium, (original of Reed 1917, pl. 6, fig. 9), GSI 11884. 10. Librigena (original of Reed 1917, pl. 6, fig. 10), GSI 11885. (8) Dolerobasilicus? sp. (Reed), Pygidium (original of Reed 1915, pl. 7, fig. 3), GSI 11535, Lower Naungkangyi Beds, Nawa, northern Shan State, Myanmar. (9) Nileus sp., Hypostome (original of Reed 1917, pl. 8, fig. 5), GSI 11904, Shihtien Formation (Darriwilian), Pupiao, Baoshan Prefecture, western Yunnan, China. (11, 12) Niobe sp. (Reed). 11a, b. Pygidium (original of Reed 1915, pl. 5, fig. 14), GSI 11516, Hwe Mawng Beds (uppermost Katian), Nati, northern part of Shan State, Myanmar, original and retrodeformation. 12. Pygidium (original of Reed 1917, pl. 6, fig. 11), GSI 11886, Shihtien Formation (Darriwilian), Shidian, Baoshan Prefecture, western Yunnan, China. Scale bars = 5 mm for 1–6, 8, 9; = 2 mm for 7, 10–12)

FIGURE 10. (1, 2) Lonchodamas? sp. (Reed) from the Li-Lu Formation (Katian), Lilu, northern Shan State, Myanmar. 1a, b. Pygidium (original of Reed 1915, pl. 5, fig. 6), GSI 11508, original and retrodeformation. 2. Cranidium (refigured from Reed 1915, pl. 5, fig. 5), GSI 11507. (3, 6) Lonchodamas shanensis (Reed) from the Hwe Mawng Beds (uppermost Katian), northern Shan State, Myanmar. 3. Pygidium (original of Reed 1915, pl. 5, fig. 3), GSI 11505, Hwe-hok. 6. Cranidium (original of Reed 1915, pl. 5, fig. 2), GSI 11504, Mong Ha. (4) Dionide hybrida (Reed), Cephalon (original of Reed 1915, pl. 5, fig. 7), GSI 11509, Hwe Mawng Beds (uppermost Katian), Hwe-hok, northern Shan State, Myanmar. (5, 8) Ovalocephalus? sp. indet. (Reed) from the Li-Lu Formation (Katian), Mân-ngai, northern part of Shan State, Myanmar. 5. Cranidium (original of Reed 1915, pl. 8, fig. 17), GSI 11563. 8. Thorax (original of Reed 1915, pl. 8, fig. 21), GSI 11567. (7) Pliomerina martellii (Reed), Cranidium (original of Reed 1917, pl. 8, fig. 15), GSI 11915, Shihtien Formation (Darriwilian), Pupiao, Baoshan Prefecture, western Yunnan, China. (9) Prionocheilus liluensis (Reed), Cranidium (original of Reed 1915, pl. 8 figs 6 and 7), GSI 11554, Li-Lu Formation (Katian), Lilu, northern Shan State, Myanmar. (10, 13) Ovalocephalus sp. (Reed) from the Li-Lu Formation (Katian), Lilu, northern Shan State, Myanmar. 10. Pygidium (original of Reed 1915, pl. 8, fig. 9), GSI 11556. 13. Cephalon; not previously figured; no GSI catalogue number. (11, 12) “Calymene” oldhami (Reed) from Lower Naungkangyi Beds (probable Darriwilian), Mâ Shio, northern Shan State, Myanmar. 11. Cephalon and thorax (original of Reed 1915, pl. 8, fig. 11), GSI 11558. 12. Cephalon and partial thorax (original of Reed 1915, pl. 8, fig. 10), GSI 11557. Scale bars = 2 mm for 1–3, 6, 8–13; = 5 mm for 4, 5; = 1 mm for 7.