Pelvic fins in teleosts: structure, function and evolution

Abstract

The pelvic fins of teleosts are paired appendages that are considered to be homologous to the hind limbs of tetrapods. Because they are less important for swimming, their morphology and function can be flexibly modified, and such modifications have probably facilitated the adaptations of teleosts to various environments. Recently, among these modifications, pelvic-fin loss has gained attention in evolutionary developmental biology. Pelvic-fin loss, however, has only been investigated in a few model species, and various biological aspects of pelvic fins in teleosts in general remain poorly understood. This review summarizes the current state of knowledge regarding pelvic fins, such as their structure, function and evolution, to elucidate their contribution to the considerable diversity of teleosts. This information could be invaluable for future investigations into various aspects of pelvic fins, which will provide clues to understanding the evolution, diversity and adaptations of teleosts.

Selection of landmarks and semilandmarks in fishes for geometric morphometric analyses: a comparative study based on analytical methods

“…For example, needlefishes use their characteristic compact set of fins to alter the flows created by body movement, a defining feature of their locomotion strategy (Liao 2002); in burrowing eels, the caudal fin is intimately related to their digging ability (De Schepper et al 2007); whereas in pelagic eels the presence of a continuous fin resulting from the confluence of dorsal, caudal and anal fins improves swimming performance (Tytell and Lauder 2004); or flying fishes, which possess extremely long pectoral fins that enable gliding flights out of the water after self-propelled jumps to escape predators or to save locomotion costs (Davenport 1994). In addition, benthic species in contact with the substratum, such as frogfishes or many scorpionfishes, use synchronized movements of pectoral and pelvic fins to move over the substrate or to maintain static positions in defensive, alert or rest behaviours (Gosline 1994, Yamanoue et al 2010, or transformations of pelvic fins into suction discs that help to the adherence on the substrate occurs in gobies (Schoenfuss and Blob 2003). The reduction or modification of pelvic fins used during aggressive or courtship behaviours are also common in balistoids (Yamanoue et al 2010), as well as the occurrence of spines in pelvic, dorsal and median fins for defence and propulsion purposes in gasterosteids and scorpionfishes (Gosline 1994).…”

“…In addition, benthic species in contact with the substratum, such as frogfishes or many scorpionfishes, use synchronized movements of pectoral and pelvic fins to move over the substrate or to maintain static positions in defensive, alert or rest behaviours (Gosline 1994, Yamanoue et al 2010, or transformations of pelvic fins into suction discs that help to the adherence on the substrate occurs in gobies (Schoenfuss and Blob 2003). The reduction or modification of pelvic fins used during aggressive or courtship behaviours are also common in balistoids (Yamanoue et al 2010), as well as the occurrence of spines in pelvic, dorsal and median fins for defence and propulsion purposes in gasterosteids and scorpionfishes (Gosline 1994). By contrast, the identification of species by including the position of fins (morphospace 2) clearly influenced the morphospace distribution.…”

“…Other anatomical parts, such as pelvic and pectoral fins or sensorial organs (barbels or illicia), are not usually included because they are not rigid structures and are difficult to preserve intact, and it is often difficult to define homologous positions of these structures between species (Bookstein 1991, Chakrabarty 2005. However, it has been demonstrated that these structures are key factors in many fish behaviours (Yamanoue et al 2010), such as movement and body position (Zuanon et al 2006), prey capture (Laurenson et al 2004) and receiving chemical stimuli (Kasumyan 2011), so they are important in the functional and ecological role of species within communities. Although many researchers currently question their use in landmark methods, claiming that they are not solid structures, that they have highly variable positions that are difficult to standardize, or even that some of them are absent (Chakrabarty 2005), fins have been applied in evolutionary (Friedman 2010, Dornburg et al 2011), phylogenetic (Vergara-Solana et al 2014, ecological (Wainwright et al 2002, Lombarte et al 2012, Farré et al 2015 and biodiversity studies (Farré et al 2013).…”

The origins of adipose fins: an analysis of homoplasy and the serial homology of vertebrate appendages

“…However, natural selection readily purges fishes of their fins. For example, pelvic fins have been lost at least 80 times in teleosts alone [72]. The maintenance of adipose fins for millions of years and the discovery of unanticipated structural complexity in some fins [15,19] implies functionality.…”

Testing otolith morphology for measuring marine fish biodiversity

“…rotated, translated and scaled landmark coordinates). Thus, the RW represents a set of specific morphological characteristics allowing the analysis of particular morphological attributes (Rohlf and Marcus 1993;Kassam et al 2002;Zelditch et al 2003). The geometric morphological analysis was performed independently for each species, obtaining a consensus (average) configuration from all otolith samples in the database.…”