Three-Dimensionally Preserved Integument Reveals Hydrodynamic Adaptations in the Extinct Marine Lizard Ectenosaurus (Reptilia, Mosasauridae)
Squamation. (A) External view of imbricating and obliquely arrayed scales (FHSM VP-401-01). Note underlying phosphatized dermal fiber bundles oriented parallel to the long axis of the animal. Black and white arrow indicates anterior. (B) External view of a flattened, rhomboidal scale (FHSM VP-401-01). Note presence of a distinct central keel. (C) External view of a three-dimensional, ovoid scale (FHSM VP-401-01). The parallel furrows adjacent to the central keel probably represent artifacts of preservation. (D) Medial surface of a rhomboid scale (FHSM VP-401-08) showing the interior ridged support of the ß-layer of the epidermis (arrows). Note medially inclined scale hinge (arrowheads). (E) Medial surface of an ovoid scale (FHSM VP-401-08) showing the supportive sculpturing of the ß-layer of the epidermis (arrows). Note folded scale hinge (arrowheads). Inset, inside of a Varanus gouldi body scale (MZLU L867/3039) showing supportive sculpturing (arrows) similar to that seen in Ectenosaurus. Scale bars, (A) 2 mm and (B–E) 0.5 mm.