Radula sp.

Feldberg, Kathrin, Schaefer-Verwimp, Alfons, Li, Ya & Renner, Matt A. M., 2022, Extending the diversity of the bryoflora in Kachin amber (Myanmar), with the description of Radula patrickmuelleri, sp. nov. and R. tanaiensis, sp. nov. (Jungermanniopsida, Porellales, Radulaceae), Fossil Record 25 (1), pp. 213-230 : 213

Radula sp.

Locality and horizon.

Amber mines southwest of the village of Tanai ca. 105 km north of Myitkyina in Kachin State, northern Myanmar, fossil enclosed in upper Albian-lower Cenomanian Kachin amber.

Specimen investigated.

GZG.BST.22043 ( Müller BuB4420), Geoscience Centre (GZG) at the University of Göttingen, Germany.

Remarks.

The new fossil GZG.BST.22043 is not very well preserved, and the identification is difficult. It strongly resembles R. cretacea (Fig. 4F-H ) in having smooth lobe cells (Suppl. material 1: Fig. S6E, F), quadrate to trapeziform lobules (Suppl. material 1: Fig. S6C, D, indicated by arrows), which are very small in relation to the lobes, and globose gemmae on the lobe margins (Suppl. material 1: Fig. S6F). However, the new fossil has obliquely patent leaves on the upper part of the shoot, whereas the posture of the lower leaves is not as dorsoventrally erect and more similar to R. cretacea (Figs 5F , Suppl. material 1: S6A-D). It also differs in having slightly narrower leaf lobes with a longer acuminate apex (Suppl. material 1: Fig. S6), though the obliqueness of the lobes makes this difficult to assess.

Figures

Figure 4. Radula patrickmuelleri sp. nov. and R. cretacea. A-E. R. patrickmuelleri, GZG. BST. 22041 (Mueller BuB 4395), holotype; A. Lobe cells, dorsal; B. Antical leaf margin with gemmae, dorsal; C. Detail of gemmae (smaller spherical bodies possibly represent air bubbles and debris); D. Lobe apex with large gemmae, dorsal; E. Lobe margin with gemmae in the initial stage of development, dorsal (initial periclinal cell division visible and indicated by black arrow); F-H. R. cretacea, PB 22484, holotype; F. Gametophyte with large gemmae on the lobe margins, ventral; G, H. Gemmae in different stages of development (initial anticlinal cell division visible and indicated by black arrow). The asterisks indicate selected gemmae in different stages of development.

Figure 5. Radula tanaiensis sp. nov. and R. heinrichsii Feldberg et al. A-E. R. tanaiensis, GZG. BST. 22042 (Mueller BuB 4329), holotype; A. Gametophyte, ventral; B. Lobe and lobule, ventral (lobule indicated by black arrow); C. Lower part of Radula - type branch; D. Medial lobe cells; E. Marginal lobe cells with thickened free exterior walls (indicated by white arrow); F, G. R. heinrichsii, GZG. BST. 22023 (Mueller BuB 3683), holotype; F. Gametophyte with microphyllous (amentulose) branches (indicated by asterisks), ventral; G. Lobe cells with central mamillae.