Figure 2.

Transversal sections of the head of E. maculatus (SL = 29 mm) displaying the swim bladder-inner ear connection. Sections are based on (A) high-resolution microCT imaging and (B) histological serial sections. (A) represents a slightly oblique slice through the microCT data stack, largely adjusted to the mechanical cutting plane in (B₁). (B₂) is a detail of (B₁). The semithin section in (B₂) especially shows that the swim bladder extension is firmly attached via connective material to a thin bony lamella which directly borders on the lagena of the inner ear. The white arrowhead in (B) indicates a disruption of the swim bladder wall; an artifact not observed in the tomographic section (white arrowhead in (A)). In contrast to the tomographic section, only a small part of the otolith is left due to decalcification in the histological sections. For the section plane refer to Figure 1. Scale bars, 1 mm (A), 500 μm (B₁), 250 μm (B₂). microCT, microtomography; SL, standard length.