Bony fishes

Silurian 440 Myr Sea levels rise, two large continents form, hothouse climate. Diversification of jawless fishes, first bony fishes invasion of land by vascular plants and arthropods... 

Phylum Chordata Tunicates, sharks, bony fishes, amphibians, reptiles, birds, mammals... 

Fig. 2.18 Chemosensory pathways, Bony Fish, (a) Peripheral ON = Olfactory nv. (input axons) GL = glomerular layer ICL = internal cell layer MCI = mitral cell layer RC = ruffed cell and CF = centrifugal fibre (from Sorensen, 1998). (b) CNS interconnections (from Bardach and Villars, 1968).

Hofmann M. and Meyer D. (1995). The extrabulbar olfactory pathway — primary olfactory fibres by passing the olfactory bulb in bony fishes. Brain Behav Evol 46, 378-388. 

Altufiev, Yu. V., Geraskin P. P. (2003). Monitoring of morpho-functional status of muscle tissue of sturgeons and bony fishes of the Caspian Sea. Problems of Regional Ecology, 6, 111-124. 

Sato, A., Figueroa, F., Murray, B.W., Malaga-Trillo, E., Zaleska-Rutczynska, Z., Sultmann, H., Toyosawa, S., Wedekind, C., Steck, N. and Klein, J. (2000) Nonlinkage of major histocompatibility complex class I and class II loci in bony fishes. Immunogenet. 51, 108-116. 

Bone and teeth in mammals and bony fishes all rely on calcium phosphates in the form of hydroxyapatite [Ca5(P04)30H]2, usually associated with around 5% carbonate (and referred to as carbonated apatite). The bones of the endoskeleton and the dentin and enamel of teeth have a high mineral content of carbonated apatite, and represent an extraordinary variety of structures with physical and mechanical properties exquisitely adapted to their particular function in the tissue where they are produced. We begin by discussing the formation of bone and then examine the biomineralization process leading to the hardest mineralized tissue known, the enamel of mammalian teeth. 

By contrast, bony fish have their olfactory organs on the dorsal side of the snout at some distance from the mouth. The olfactory system in fish involves the first (olfactory) cranial nerve, while the ninth (glossopharyngeal) and other nerves serve the sense of taste. 

FIGURE 5.2 The olfactory organ in fish, (a) The nostril positions in sculpin (Cottidae) b) nostril position in spiny eel (Mastacembelidae) (c) a skin flap separates in- and outflow, an arrangement typical for bony fish (here Catastomidae) (d) the olfactory lamellae are located in the floor of the olfactory capsule (here minnow, Phoxinus). (From C. E. Bond Biology of Fishes.)... 

In fish, both taste and olfactory stimuli are waterborne. However, taste involves the seventh, ninth or tenth cranial nerves, in contrast to the first cranial nerve for smell. Elasmobranchs have their taste buds in the mouth and pharynx, but in bony fish they occur around the gills, on barbels and pectoral fins, and also scattered over the rest of the body surface. They crowd particularly in the roof of the mouth, forming the palatal organ. The taste receptor cells are arranged as a bundle to form a taste bud. Like other vertebrates, fish have receptors for sweet, sour, salty, and bitter. For instance, goldfish reject quinine-treated food pellets (Jobling, 1995). Many fish species are particularly sensitive to acidic taste characteristics. The responses of fish to amino acids will be discussed in Chapter 12. 

Not surprisingly, much research in sharks, skates and rays has focused on the responses of sharks to human body odors. Human blood attracts sharks, while sweat does not, and urine was even slightly repellent (Tester, 1963). Practitioners use whale meat and mixtures of fish meal and fish oils as shark attrac-tants. In both carnivorous and herbivorous bony fish (Osteichthyes) smell deals with prey odors, social odors, and chemical stimuli in homing, and it is mediated by the first cranial nerve, the olfactory nerve. By contrast, taste serves in detection and selection of food and avoidance of toxic food, and it employs the facial, glossopharyngeal, vagal, and hypoglossal nerves. 

Zrnn, C., Lopata, A., Visser, M., and Potter, P. C. (1997). The spectrum of allergy to South African bony fish (Teleosti). Evaluation by double-blind, placebo-controlled challenge. South Afr. Med. J. 87, 146-152. 

Kimura, S. (1983). Vertebrate skin type I collagen Comparison of bony fishes with lamprey and calf. Comp. Biochem. Physiol. 74, 525-528. 

Bony fish (winter flounder) Atlantic salmon Hepcidin-like Douglas et al. (2003)... 

Douglas, S. E., Gallant, J. W., Liebscher, R. S., Dacanay, A., and Tsoi, S. . M. (2003). Identification and expression analysis of hepcidin-like antimicrobial peptides in bony fish. Dev. Comp. Immunol. 27, 589-601. 

Ammonotelic animals most aquatic vertebrates, such as bony fishes and the larvae of amphibia... 

Ammonia is also the major nitrogenous end product in some of the simpler aquatic and marine animal forms, such as protozoa, nematodes, and even bony fishes, aquatic amphibia, and amphibian larvae. Such animals are called am-monotelic. But in many animals, NH3 is toxic, and its removal by simple diffusion is difficult. Thus, in terrestrial snails and amphibia, as well as in other animals living in environments in which water is limited, urea is the principal end product (fig. 22.6). Urea formation also helps to maintain osmotic balance with seawater in cartilagenous fishes. In such animals, most of the urea secreted by the kidney glomerulus is reabsorbed by the tubules. Indeed, the amount of nitrogen excreted by the kidneys of fishes is small com-... 

---