A biorobotic pectoral fin was developed and used to study how the flexural rigidities of fin rays within a highly deformable fish fin affect the fin's propulsive forces. The design of the biorobotic fin was based on a detailed analysis of the pectoral fin of the bluegill sunfish (Lepomis macrochirus). The biorobotic fin was made to execute the kinematics used by the biological fin during steady...

Acanthoplesiops cappuccino is described from the 16.4 mm SL holotype collected from Jeddah, Saudi Arabia, Red Sea. The following combination of characters distinguishes it from congeners: dorsal-fin rays XVIII,4; anal-fin rays VII,4; pectoral-fin rays 18; caudal fin not connected to last rays of dorsal and anal fins by membrane; and caudal peduncle with a pale yellowish brown bar, which extends...

Females often choose to associate with males that have exaggerated traits. In fishes, this may reflect an overall preference for larger size in a potential mate. Female zebrafish (Danio rerio) prefer males with larger bodies but not longer fins. The availability of mutant and transgenic strains of zebrafish make this a unique model system in which to study the role of phenotypic variation in so...

The fact that some organisms are able to regenerate organs of the correct shape and size following amputation is particularly fascinating, but the mechanism by which this occurs remains poorly understood. The zebrafish (Danio rerio) caudal fin has emerged as a model system for the study of bone development and regeneration. The fin comprises 16 to 18 bony rays, each containing multiple joints a...

Scaling studies for an actively controlled curvature robotic pectoral fin are presented in detail. Design, development, and analysis of the fin are conducted using a combination of computational fluid dynamics tools and experimental tests. Results include a Generation 2 (Gen2) fin design with approximately 3x more surface area and a slightly larger aspect ratio compared with our Generation 1 (G...

Swimming movements in boxfishes were much more complex and varied than classical descriptions indicated. At low to moderate rectilinear swimming speeds (<5 TL s(-1), where TL is total body length), they were entirely median- and paired-fin swimmers, apparently using their caudal fins for steering. The pectoral and median paired fins generate both the thrust needed for forward motion and the con...

Studies of the kinematics of the pectoral fins in fishes have focused on fins as devices for propulsion or maneuvering. Studying pectoral fin function in benthic fishes is an opportunity to understand how the fins are used in a broader range of fin-based behaviors, especially those involving substrate contact. Morphological specializations of the pectoral fins, hypothesized adaptations for subs...

Ray-finned fishes actively control the shape and orientation of their fins to either generate or resist hydrodynamic forces. Because of the emergent mechanical properties of their segmented, bilaminar fin rays (lepidotrichia), and actuation by multiple muscles, fish can control the rigidity and curvature of individual rays independently, thereby varying the resultant forces across the fin surfa...

Two species of dwarfgoby are described from the Ryukyu Islands, Japan. Eviota flebilis n. sp. belongs to cephalic sensory-pore system pattern 2 (lacking only IT pore), has a dorsal/anal fin-ray formula of 8/7, unbranched pectoral-fin rays, the 5th pelvic-fin ray 12.9% of the 4th, a distinctive narrow, red-orange line under the eye, and a dark vertical line at the caudal-fin base. Eviota specca ...