Developmental constraints on fin diversity

Abstract

The fish fin is a breathtaking repository full of evolutionary diversity, novelty, and convergence. Over 500 million years, the adaptation to novel habitats has provided landscapes of fin diversity. Although comparative anatomy of evolutionarily divergent patterns over centuries has highlighted the fundamental architectures and evolutionary trends of fins, including convergent evolution, the developmental constraints on fin evolution, which bias the evolutionary trajectories of fin morphology, largely remain elusive. Here, we review the evolutionary history, developmental mechanisms, and evolutionary underpinnings of paired fins, illuminating possible developmental constraints on fin evolution. Our compilation of anatomical and genetic knowledge of fin development sheds light on the canalized and the unpredictable aspects of fin shape in evolution. Leveraged by an arsenal of genomic and genetic tools within the working arena of spectacular fin diversity, evolutionary developmental biology embarks on the establishment of conceptual framework for developmental constraints, previously enigmatic properties of evolution.

Morphological evolution and diversity of pectoral fin skeletons in teleosts

“…The four proximal radials are largely conserved in the species we examined. These findings follow the “four-basal rule”, which describes the constraint on the number of proximal radials and seems to arise in the stem and crown groups of teleosts (De Pinna, 1996; Johnson and Patterson, 1996; Arratia, 1999; Enny et al ., 2020). Some species have modified pectoral fin morphology such that the shape of the extremity is extremely wide and enlarged, but there is no change in the number of proximal radials.…”

“…Fish fins have also evolved to show morphological variations in their skeletons. In chondrichthyans (such as shark and ray) and basal actinopterygians (such as sturgeon, gar and amia), the number of radial bones differs between species, and the skeletal variations give rise to specialization of fin size and shape as seen in pectoral fins of skates and rays (Jessen, 1972; Dillman and Hilton, 2015; Riley, Cloutier and Grogan, 2017; Enny et al ., 2020). On the other hand, fishes in the derived and largest group (Teleostei) of the actinopterygians, teleosts, are thought to have a relatively conserved pattern of fin skeletal elements.…”

Investigation of osteogenesis changes in medaka larvae reared in normal gravity, simulated-microgravity and hypergravity environments

“…Additionally, the present results showed that the fins grew upward in medaka exposed to the hypergravity environment. The tail fin has been shown to have an optimal shape (Zhiqiang and Chuijie 2013), with its structure remodeled according to specific types of fin motion (Enny et al 2020) and the angle of the caudal fin having an effect on thrust production (Matta et al 2019). Thus, the present finding of an upward-facing fin phenotype may indicate that the morphology of the medaka fin has an ability to change to adapt to a hypergravity environment.…”

New Species Can Broaden Myelin Research: Suitability of Little Skate, Leucoraja erinacea

“…Sequences of many non-mammalian genomes, including elasmobranchs [ 5 , 6 , 7 , 8 ], gar [ 9 ], coelacanth [ 10 ], lamprey [ 11 , 12 ] and hagfish [ 13 ], coupled with the absence of an extra genome duplication characteristic of teleost fish and amphibians offer distinct possibilities. Additionally, slow evolutionary rates in many species [ 9 , 14 , 15 , 16 ] coupled with expanding uses in developmental and molecular biology [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ], taken as a whole, make expansions to new species attractive. Undoubtedly, accompanying additions of new animal models will emerge techniques and approaches that will strengthen and re-enforce these choices and provide opportunities to test these concepts.…”