Megapalaeolenus deprati (Mansuy, 1912)

Zhao, Wenyu, Liu, Jianni & Bicknell, Russell D. C., 2020, Geometric morphometric assessment of Guanshan trilobites (Yunnan Province, China) reveals a limited diversity of palaeolenid taxa, Palaeontologia Electronica (a 22) 23 (2), pp. 1-15 : 10-11

Megapalaeolenus deprati (Mansuy, 1912)

Figure 6

1912 Palaeolenus deprati Mansuy. Mansuy , p. 30, pl. 4, fig. 3a, b.

1941 Palaeolenus deprati Mansuy. Lu , p. 84, pl. 1, fig. 12a-c.

1965 Palaeolenus deprati Mansuy. Lu, Chang, Chu, Chien, and Hsiang , p. 83, pl. 12, fig. 10.

1966 Megapalaeolenus deprati Mansuy. Chang , p. 150

1978 Megapalaeolenus deprati Mansuy. Zhou and Lin , p. 148, pl. 24, figs. 5, 6.

1980 Megapalaeolenus deprati Mansuy. Chang, Lu, Chu, Chien, Lin, Zhou, Zhang, and Yuan , p. 232, pl. 72, figs. 2-5.

2007 Megapalaeolenus deprati Mansuy. Luo, Li, Hu, Fu, Hou, You, Pang, and Liu , p. 317, pl. 3, figs. 1-14.

2008 Megapalaeolenus deprati Mansuy. Luo, Li, Hu, Fu, Hou, Liu, Chen, Li, Pang, and Liu , p. 77, pl. 19, figs. 4-14.

2013 Megapalaeolenus deprati Mansuy. Hu, Zhu, Luo, Steiner, Zhao, Li, Liu, and Zhang , p. 101, figs. 125-129.

2014 Megapalaeolenus deprati Mansuy. Luo, Hu, Chen, Zhan, and Lu , p. 564, pl. 1, figs. 1-8; pl.

2, figs. 1-7.

Referred material. HLQ-3, HLQ-14, HLQ-19, HLQ-22, HLQ-33, HLQ-37, HLQ-39, HLQ-40, HLQ-46, HLQ-50.

Diagnosis. Megapalaeolenus with short (tr.) ocular ridges, long (exs.) palpebral lobes, subparallel to the axial furrow with a robust glabella that is expanded anteriorly, a relatively narrow (tr.) fixigena, more curved pleural spines and wider (tr.) pleural lobes.

Description. Body ovate, with a length (sag.) of 2- 3 cm. Cephalon half elliptic. Palpebral lobe consistently longer (exs.) than ocular ridge, subparallel to axial furrow. Glabella rounded and its anterior part expanded. The number of glabellar furrows is variable due to taphonomic alteration, but can be up to four. The fixigena is narrower (tr.) to equally wide compared to the librigena. The postero-lateral projection is relatively short (sag.) and wide (tr.). The number of thoracic tergites is 15. The pleural lobe is pronouncedly wider (tr.) than axial lobe. The semi-elliptical pygidium is much smaller than the cephalon and is divided into two parts by one transverse furrow. The axial lobe of pygidium is relatively wide compared to the pleural lobe.

Remarks. The geometric morphometric results show that Megepalaeolenus deprati and Palaeolenus douvillei occupy different areas of morphospace. M. deprati can be differentiated from P. douvillei by more rounded glabella, longer (sag.) palpebral lobes, shorter (tr.) ocular ridges, and more developed posterolateral projections. Additionally, pleural spines of M. deprati are more curved and its pleural lobe is pronouncedly wider (tr.) than axial lobe.

Figures

FIGURE 6. Articulated and disarticulated specimens of Megapalaeolenus deprati from the Huanglongqing Section. A. HLQ-39A. B. HLQ-19. C. HLQ-37. D. HLQ-50. E. HLQ-13. F. HLQ-33. Scale bars equal 5 mm.