The comparative morphology of the musculature controlling the pectoral free rays in scorpaenoid fishes.

Free rays are ventral pectoral fin rays (lepidotrichia) that are free of the pectoral fin webbing. They are some of the most striking adaptations of benthic fishes. Free rays are used for specialized behaviors such as digging, walking or crawling along the sea bottom.

Fin ray patterns at the fin-to-limb transition.

The fin-to-limb transition was marked by the origin of digits and the loss of dermal fin rays. Paleontological research into this transformation has focused on the evolution of the endoskeleton, with little attention paid to fin ray structure and function. To address this knowledge gap, we study the dermal rays of the pectoral fins of 3 key tetrapodomorph taxa- (Rhizodontida), (Tristichopteridae), and (Elpistostegalia)-using computed tomography.

Variation in flexural stiffness of the lepidotrichia within and among the soft fins of yellow perch under different preservation techniques.

Although the ray-finned fishes are named for their bony, segmented lepidotrichia (fin rays), we are only beginning to understand the morphological and functional diversity of this key vertebrate structure. Fin rays support the fin web, and their material properties help define the function of the entire fin. Many earlier studies of fin ray morphology and function have focused on isolated rays, or on rays from only one or two fins.

Functional implications of morphological specializations among the pectoral fin rays of the benthic longhorn sculpin.

Fin ray structure in ray-finned fishes (Actinopterygii) largely defines fin function. Fin rays convert the muscle activity at the base of the fin to shape changes throughout the external fin web. Despite their critical functional significance, very little is known about the relationship between form and function in this key vertebrate structure.

Functional implications of variation in pectoral fin ray morphology between fishes with different patterns of pectoral fin use.

In this study, I compare the morphology from the pectoral fin rays from the benthic longhorn sculpin (Myoxocephalus octodecimspinosus) to those from a species that does not use its fins for substrate contact, the yellow perch (Perca flavescens). I use CT scanning technology to compare the shape and structure of the paired hemitrichia that make up the pectoral fin rays between these species. I found that the structure of hemitrichia of the fin rays in yellow perch is consistent with previous descriptions for pelagic fishes.