FIGURE 2.

Schematic drawing of the musculotendinous system (MTS) of different body regions in Astronesthes sp. (MNHN 2000 0576, 118 mm SL). (a) Myoseptum of V24 at 0,43L. ENTB and EPTB present. ECT present. (b) Myoseptum of V31 at 0,55L. The ENB and EPB are proximally forked. The antero‐medial branch (ENTB/EPTB) of the forked intermuscular is attached to the neural arch epaxially and the parapophysis hypaxially, whereas the antero‐lateral branch of the forked bony element represents an ossification in the lateral tendon and extends from the DAC/VAC to the DPC/VPC. ECT present. (c) Myoseptum of V46 at 0,80L. Intermuscular ossification represents the lateral tendon bone (LTB) epaxially and hypaxially extending from the anterior cones (DAC/VAC) into the posterior cones (DPC/VPC). (d) Caudal tendons that insert on caudal‐fin rays and represent LTs of V50–V56. (e) Overview of the different body regions and their MTS. Abbreviations: DAC, dorsal anterior cone; DPC, dorsal posterior cone; ECT, epicentral tendon; ENTB, epineural tendon bone; EPTB, epipleural tendon bone; F.NL, foramen for the nervus lateralis; HM, horizontal midline; LT, lateral tendon; LTB, lateral tendon bone; MT, myorhabdoid tendon; R, rib; RMTs, tendons within red muscle bundles; VAC, ventral anterior cone; VPC, ventral posterior cone