Formation of dermal skeletal and dental tissues in fish: a comparative and evolutionary approach

Abstract

Osteichthyan and chondrichthyan fish present an astonishing diversity of skeletal and dental tissues that are often difficult to classify into the standard textbook categories of bone, cartilage, dentine and enamel. To address the question of how the tissues of the dermal skeleton evolved from the ancestral situation and gave rise to the diversity actually encountered, we review previous data on the development of a number of dermal skeletal elements (odontodes, teeth and dermal denticles, cranial dermal bones, postcranial dermal plates and scutes, elasmoid and ganoid scales, and fin rays). A comparison of developmental stages at the tissue level usually allows us to identify skeletogenic cell populations as either odontogenic or osteogenic on the basis of the place of formation of their dermal papillae and of the way of deposition of their tissues. Our studies support the evolutionary affinities (1) between odontodes, teeth and denticles, (2) between the ganoid scales of polypterids and the elasmoid scales of teleosts, and (3) to a lesser degree between the different bony elements. There is now ample evidence to ascertain that the tissues of the elasmoid scale are derived from dental and not from bony tissues. This review demonstrates the advantage that can be taken from developmental studies, at the tissue level, to infer evolutionary relationships within the dermal skeleton in chondrichthyans and osteichthyans.

Structure and mechanical properties of selected protective systems in marine organisms

“…While scales can vary greatly in size, shape and arrangement from species to species, they have been classified into three relevant general groups: placoid, elasmoid (with two sub-groups: cycloid and ctenoid) and cosmoid [13,180]. A fourth group, ganoid scales, is rare and only reported in predominantly freshwater fish such as gars [187] and bichirs [181] and, as a Adapted from: (a) [180], (b) [13,188], (c) [13]. result, will not be discussed here.…”

“…25b) are found on many cartilaginous fish, including sharks and rays. In shark species, they are specified as odontodes, where they display a "tooth-like" appearance [188]. They consist of an outer layer with large vascular spaces and a lamellar inner layer [189].…”

Genetic and developmental basis of cichlid trophic diversity

“…Evolution and development of cichlid tooth shape Dentition figures prominently in discussions of adaptive radiation in groups as distinct as hominids and teleosts (McCollum and Sharpe, 2001;Sire and Huysseune, 2003). The observation that differences in tooth shape may be controlled by changes at a small number of loci suggests that this character has the potential to respond rapidly to selection.…”

Postembryonic staging of wild‐type goldfish, with brief reference to skeletal systems

“…Comparative studies of ontogenetic process require not only embryonic, but also postembryonic staging tables, as several important morphogenetic processes which form characteristic features of each species (for example, internal and external skeletal structures and scale patterns) are known to proceed during postembryonic stages (Arratia et al, 1990, 1991; Cubbage and Mabee, 1996; Schilling and Kimmel, 1997; Van der Heyden and Huyssune, 2000; Van der Heyden et al, 2000; Witten et al, 2001; Yelick and Schilling, 2002; Mabee et al, 2002; Bird and Mabee, 2003; Sire and Huysseune, 2003; Webb and Shirey, 2003; Elizondo et al, 2005; Sire and Akimenko, 2004; Thorsen and Hale, 2005; Patricia et al, 2007; Patterson et al, 2008; Parichy et al, 2009; Kimmel et al, 2010; Budi et al, 2011; Bensimon‐Brito et al, 2012). However, at present there is no widely available postembryonic developmental staging table for goldfish, in practice.…”