FIGURE 1. Map of Northwest Germany with the place of discovery (Bocholt) in North Rhine Westfalia State near the Dutch border.
FIGURE 2. Extract of the Cenozoic stratigraphy of the Lower Rhine area (modified from Hiss, 2013). The mysticete periotics were found in deposits of the Biemenhorst subformation (red font).
FIGURE 3. Schematic drawings of a generalised mysticete periotic bone showing the measurements taken from the Bocholt fossils (see: Description).
FIGURE 4. Right periotic bone of Balaenomorpha ‘type Bocholt A’ (MB.Ma. 51619) in (A) ventral, (B) dorsal, (C) medial, (D) lateral, and (E) posterior view.
FIGURE 5. Left periotic bone of Balaenomorpha ‘type Bocholt B’ (MB.Ma. 51618) in (A) ventral, (B) dorsal, (C) medial, (D) lateral, (E) anterior, and (F) posterior view.
FIGURE 6. Right periotic bone of the referred specimen (MB.Ma. 51621) of Balaenomorpha ‘type Bocholt B’ in (A) ventral, (B) dorsal, (C) anterior, (D) posterior, and (E) dorsomedial view.
FIGURE 7. Fundus of the internal acoustic meatus (FIAM). (A) Schematic diagram after Gaillard (2022) showing the accurate positions of crista transversa (synonymous with crista falciformis) and crista verticalis (synonymous with Bill’s bar), (B) FIAM of Tursiops truncatus , ZMB_MAM 27159, showing pathways of CN VII and CN VIII, with labels colour code related to A, (C) FIAM of Tursiops truncatus, ZMB_MAM 27159, marked by blue ellipse.
Remarks: opening of CN VII = passage for Nervus facialis; CN VIIIc = passage for Nervus cochlearis, CN VIIIvs = passage for superior division of vestibular nerve (Nervus utriculoampullaris), CN VIIIvi = passage for inferior division of vestibular nerve (Nervus sacculoampullaris), Ni = passage for Nervus intermedius.
FIGURE 8. FIAM in Eomysticetus whitmorei , ChM PV4253, from deep inside (A) to ‘surface’ (C). For innervation, see remarks of Figure 7.
FIGURE 9. FIAM in Parietobalaena palmeri , USNM 13874, from deep inside (A) to ‘surface’ (C). For innervation, see remarks of Figure 7.
FIGURE 10. FIAM in Balaenoptera borealis, ZMB_MAM 77323, from deep inside (A) to ‘surface’ (C). For innervation, see remarks of Figure 7.
