Anatomy of fishes pdf

Anatomy and evolution of chirocentrid fishes : Kansas Univ. The geologic range of the Chirocentridae exceeds that of other teleostean families. Where the Elasmosaurs Roamed. Williston, S. Cretaceous fishes: selachians and pycnodonts. Anatomy and Evolution of Chirocentrid Fishes. Bardack, D. Kansas Paleont. The pectoral and pelvic fins are known as the paired fins , because there are two left and right fins of each. The distal part of a fin is the outer marginal part; the proximal or basal part of a fin is that portion nearest the body.

The adipose fin is a short, fleshy, median fin situated on the caudal peduncle. Unable to display preview. Download preview PDF. While passing through the alimentary canal, the food is broken down physically and chemically and ultimately solubilized so that degraded products can be absorbed.

The absorption occurs chiefly through the wall of intestine. The undigested food and other substances within the alimentary canal such as mucus, bacteria, desquamated cells and bile pigments and detritus are excreted as faeces.

The peristaltic movement and local contractions are important and help the food to pass through the gut. The local contraction displaces intestinal contents proximally and distally. The alimentary canal of fish consists of mouth, which opens into buccopharynx, which in its turn opens into the oesophagus. In most teleost, the food reaches the mouth by sucking it by enlarging their buccal and opercular cavities.

The pressure in the buccal and opercular cavities and pressure of water around the fish, are important for sucking. It is also recorded that to produce strong negative pressure, all muscles principally involved have to exert tension near maximum isometric tension. Osse made an electromyography study of feeding in Perca and confirmed the sequence of muscle action inferred from anatomical studies and by analogy with respiration.

The mechanism of feeding behaviour in fishes is very complicated. There are generally several kinds of stimuli for feeding. The common factors affecting the internal motivation or drive for feeding include season, time of the day, light intensity, time and nature of last feeding, temperature and any internal rhythm. The visual, chemical, taste and lateral line system also control the momentary feeding act.

The interaction of these groups of factors determine when and how a fish will feed and what it will feed upon. The role of visual and olfactory factors in connection with feeding behaviour has been studied by experimental conditions by Groot He found visual, chemical and mechanical sense organs in Pleuronectidae, Soleidae, and Bothidae belongs to the family of flat fishes, Pleuronectiformes.

Soleidae are polychaet mollusc feeder, feed during night, find their food mainly by olfactory clues, but still have the capability of finding their food visually, Table 1. The barbels help the fish to locate food grubbed from soft bottom material.

Amongst teleosts, about Fish are animals that are cold-blooded, have fins and a backbone. Most fish have scales and breathe with gills. There are about 22, species of fish that began evolving around million years ago. The largemouth bass illustrated above has the typical torpedo- like fusiform shape associated with many fishes.

Fins are appendages used by the fish to maintain its position, move, steer and stop. They are either single fins along the centerline of the fish, such as the dorsal back fins, caudal tail fin and anal fin, or paired fins, which include the pectoral chest and pelvic hip fins. Fishes such as catfish have another fleshy lobe behind the dorsal fin, called an adipose fat fin that is not illustrated here.

The dorsal and anal fins primarily help fish to not roll over onto their sides. The caudal fin is the main fin for propulsion to move the fish forward. The paired fins assist with steering, stopping and hovering. Scales in most bony fishes most freshwater fishes other than gar that have ganoid scales, and catfish which have no scales are either ctenoid or cycloid.

Ctenoid scales have jagged edges and cycloid have smooth rounded edges. Ctenii are tiny, comblike projections on the exposed posterior edge of ctenoid scales. Bass and most other fish with spines have ctenoid scales composed of connective tissue covered with calcium. Most fishes also have a very important mucus layer covering the body that helps prevent infection. Anglers should be careful not to rub this "slime" off when handling a fish that is to be released. Catfish have notably hard sharp fins that anglers should be wary of.

The soft dorsal and caudal fins are composed of rays, as are portions of other fins. Rays are less rigid and frequently branched. The gills are the breathing apparatus of fish and are highly vascularized giving them their bright red cover. An operculum gill cover that is a flexible bony plate protects the sensitive gills. Water is "inhaled" through the mouth, passes over the gills and "exhaled" from beneath the operculum.

Fish see through their eyes and can detect color. The eyes are rounder in fish than mammals because of the refractive index of water and focus is achieved by moving the lens in and out, not distorting it as in mammals. Paired nostrils, or nares, in fish are used to detect odors in water and can be quite sensitive.

Eels and catfish have particularly well developed senses of smell. The mouths shape is a good clue to what fish eat.