Reedocalymene unicornis ( Reed, 1917 )

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 : 337

Reedocalymene unicornis ( Reed, 1917)

Figs 12.1–6 , 8 , 10

1917 Calymene unicornis sp. nov.; Reed p. 52–54, pl. 8, figs 10–13.

1951 Reedocalymene unicornis ( Reed, 1917) ; Kobayashi, p. 45, pl. 4, figs 12–14.

1975 Reedocalymene unicornis ( Reed, 1917) ; Lu, p. 447.

2002 Reedocalymene unicornis ( Reed, 1917) ; Turvey, p. 55.

2005 Reedocalymene unicornis ( Reed, 1917) Turvey , p. 550.

Material. Lectotype (selected by Turvey, 2005): damaged cephalon, Figs 12.1-3 ( Reed, 1917, pl. 8, fig. 10), GSI 11913. Additional type material: cephalic fragments, Figs 12.5 /8 and 12.10/6 ( Reed, 1917, pl. 8, figs 12,11 respectively), GSI 11912; pygidium, Fig. 12.4 ( Reed, 1917, pl. 8, fig. 13), GSI 11911? All material from the Shihtien Formation (Darriwilian) at Pupiao, western Yunnan.

Discussion. Reed (1917) described the limited material of this species in some detail, and new cast material does not greatly enhance our knowledge. The lectotype is more distorted than Brock’s original drawing suggests, and the upward curvature of the anterior pro/jection shown by Reed (1917, pl. 8, fig. 10a, GSI 11913) may have been exaggerated by this. However, the comparatively laterally expanded L1 on the glabella is probably a real feature, which is not so clear on the original drawing. This differs from other species assigned to the genus by Lu (1975) that have a uniformly deeply parabolic glabellar outline. In this respect R. unicornis more closely resembles species that have been assigned to Calymenesun and Vietnamia (see Turvey, 2002). However, it is possible that deformation may have contributed to this distinction. A very incomplete cranidium shows the outline of the posterior fixed cheek. A backwardly displaced free cheek with a narrow border is best displayed on Reed’s pl. 8, fig. 11; we have not been able to cast this specimen, nor the only example of a pygidium ( Reed, 1917, pl. 8, fig. 13) reproduced here. The imperfect thorax and pygidium from Pupiao figured by Reed (1917, pl. 8, fig. 14) is refigured here ( Fig. 12.7 ). It is likely to belong to a reedocalymenine, and possibly to Reedocalymene rather than Neseuretinus . However, the pygidial pleural ribs appear to be more pronounced than is the case with the pygidium assigned with more certainty to R. unicornis by Reed (1917, pl. 8, fig.13), and its assignment must remain uncertain.

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.

FIGURE 12. (1–6,8,10) Reedocalymene unicornis (Reed) from the Shihtien Formation (Darriwilian), Pupiao, Baoshan Prefecture, western Yunnan, China. 1–3. Cranidium (original and refigured of Reed 1917, pl. 8, fig. 10a,b), GSI 11913. 4. Pygidium (refigured from Reed 1917, pl. 8, fig. 13), GSI 11911?. 5. Partial cranidium (original of Reed 1917, pl. 8, fig. 12); GSI 11912?. 6. Partial cranidium (refigured from Reed 1917, pl. 8, fig. 11), GSI 11912?. 8. Partial cranidium (refigured from Reed 1917, pl. 8, fig. 12), GSI 11912?. 10. Partial cranidium (original of Reed 1917, pl. 8, fig. 11), GSI 11912?. (7) Reedocalymene? sp. (Reed), Thorax and pygidium (original of Reed 1917, pl. 8, fig. 14), GSI 11914, Shihtien Formation (Darriwilian); Pupiao, Baoshan Prefecture, western Yunnan, China. (9,11–15) Neseuretinus aff. birmanicus (Reed) from the Li-Lu and Pupiao formations (Katian). 9. Cranidium (lectotype, original of Reed 1906, pl. 5, fig. 27), GSI 8341, Kunkaw, northern Shan State, Myanmar. 11. Cranidium; CMC IP 91532, Pupiao, Baoshan Prefecture, western Yunnan, China. 12. Pygidium and partial thorax, CMC IP 91533, Pupiao, Baoshan Prefecture, western Yunnan, China. 13. Pygidium, CMC IP 91534, Pupiao, Baoshan Prefecture, western Yunnan, China. 14, 15. Pygidium (original of Reed 1915, pl. 8, fig. 5), GSI 11553, Loikok, northern part of Shan State, Myanmar, dorsal and right lateral views. Scale bars = 2 mm for 1–6, 8–10, 12–15; = 5 mm for 7, 11.