DOCSLIB.ORG

MODULE 8 BONY FISHES (Osteichthyes: Class Sarcopterygii and Class Actinopterygii)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
MODULE 8 BONY FISHES (Osteichthyes: Class Sarcopterygii and Class Actinopterygii) BONY FISHES (OSTEICHTHYES: CLASS SARCOPTERYGII AND CLASS ACTINOPTERYGII) MODULE 8 MODULE 8 BONY FISHES (Osteichthyes: Class Sarcopterygii and Class Actinopterygii) Unit 1 General Characteristics and Classification Sub-Unit 1: General Characteristics 1. The skeleton is more or less bony, notochord may persist in part and the tail is usually homocercal. 2. Skin has mucous glands and is embedded with dermal scales which are usually of three types: ganoid, cycloid or ctenoid scales. Some are without scales. 3. They possess both median and paired fins, with fin rays of cartilage or bone. 4. Mouth is usually terminal with or without teeth; jaws are present; olfactory sacs are paired and may or may not open into the mouth. 5. Respiration is by gills supported by bony arches and covered by a common operculum. 6. Swim bladder often present with or without duct connected to the pharynx. 7. The circulatory system consists of a two-chambered heart; arterial and venous systems, and characteristically four pairs of aortic arches; blood contains nucleated red cells. 8. Nervous system consists of a brain with small olfactory lobes and cerebrum; large optic lobes and cerebellum. There are ten pairs of cranial nerves and three pairs of semi- circular canals. 9. Sexes are separate although there is sex reversal in some. Gonads are paired. Fertilization is usually external. Sub-unit 2: Classification The Osteichthyes is divided into two classes: 1. Class Sarcopterygii (lobe finned fishes) 2. Class Actinopterygii (ray-finned fishes) a. Subclass Cladistia (bichirs) b. Subclass Chondrostei (Gr. chondros, cartilage + osteon, bone) e.g. sturgeons and paddlefishes AOE 1 BONY FISHES (OSTEICHTHYES: CLASS SARCOPTERYGII AND CLASS ACTINOPTERYGII) MODULE 8 c. Subclass Neopterygii (Gr. holos, entire + osteon, bone) e.g. bowfin, gars and teleosts. Unit 2 Class Sarcopterygii Members of the Sarcopterygii (G. sarkos, flesh + pteryx, fin or wing) includes the extinct rhipidistians, coelocanths and the lungfishes, which are collectively referred to as the lobe-finned fishes. The rhipidistians have a fusiform shape, two dorsal fins and a heterocercal tail. The paired fins bore sharp resemblance to tetrapod limb. They are believed to have been ancestors of ancient amphibians. The coelocanths have only one living order with two species: the West Indian Ocean coelocanth, Latimeria chalumnae (named after Majorie Courtenay- Latimer, South African Museum Director) and the Indonesian coelocanth, Latimeria menadoensis. The last coelacanth were believed to have become extinct 70 million years ago. However, in 1938, people fishing in deep water off the coast of South Africa brought up fishes that were identified as coelocanths. Since then, numerous other specimens have been caught in deep water around the Comoro Islands off Madagascar, where it was learned, native Comoran fishermen occasionally caught them with hand lines at great depths. Latimeria is large, up to 80kg, and has heavy scales. The tail is diphycercal but possesses a small lobe between the upper and lower caudal lobes, producing a three-pronged structure. Coelocanths show some degenerative features, such as more cartilaginous parts and a swim Figure 1: Latimeria chalumnae bladder that was either calcified or else persisted as a mere vestige. They also lack internal nostrils. Ancient coelocanths lived in freshwater lakes and rivers; therefore, the ancestors of Latimeria must have moved from freshwater habitats to the deep sea. AOE 2 BONY FISHES (OSTEICHTHYES: CLASS SARCOPTERYGII AND CLASS ACTINOPTERYGII) MODULE 8 The lung fishes and are represented today as three genera. All live in regions where seasonal droughts are common. The least specialized is Neoceratodus, the living Australian lungfish (from freshwaters of Queensland, Australia), which may which Figure 3: Neoceratodus may attain a length of 1.5m. This lungfish is able to survive in stagnant, oxygen-poor water by coming out and gulping air into its single lung, but it cannot live out of water. The other two genera are found in freshwater rivers and lakes of tropical Africa, Protopterus, and tropical South America, Lepidosiren. They have lost the use of gills for gas exchange and can survive when rivers and lakes are dry Figure 2: Lepidosiren by burrowing into the mud. Protopterus lives in African streams and rivers that run completely dry during the dry season (the West African lungfish is called Protopterus annectens). The fish burrows down at the approach of the dry season and secretes a copious slime that is mixed with mud to form a hard cocoon in which it aestivates until the rains return. They then emerge from their burrows to feed Figure 4: Protopterus and reproduce. Unit 3 Class Actinopterygii They are referred to as ray-finned fishes because their fins lack muscular lobes. They usually possess swim bladders, gas-filled sacs along the dorsal wall of the body cavity that regulate buoyancy. A modern classification system divides the Actinopterygii into three subclasses; these are the Cladistia (bichirs), Chondrostei, (sturgeons and paddlefishes); and the Neopterygii (gars, bowfin and teleosts). Members of the subclass Cladistia (bichirs) have long, slender bodies that are covered by rhombic ganoid scales; examples include bichirs of Nigerian freshwaters such as Polypterus senegalus and P. bichir. Polypterus has a lung-like swim bladder. The sturgeons and AOE 3 BONY FISHES (OSTEICHTHYES: CLASS SARCOPTERYGII AND CLASS ACTINOPTERYGII) MODULE 8 paddlefishes have cartilaginous skeletons. Chondrosteans have a tail with a large upper lobe. Sturgeons are large (up to 1,000kg), and bony plates cover the anterior portion of the body, heavy scales cover the tail. The sturgeon mouth is small, and jaws are weak. They feed on invertebrates using their snout and they are valued for their caviar (eggs). Paddlefishes are large freshwater chondrosteans. They have large, paddle-like rostrum that is innervated with sensory organs believed to detect weak electrical fields. They swim through the water with their large mouths open, Figure 5: (a) Bichir (b) Sturgeon filtering crustaceans and small fishes. (c) Paddlefish The Neopterygii comprise the bowfin, gars and teleosts. The bowfin, Amia (Greek name of perch- like fish) of shallow weedy waters of the Great Lakes and Mississippi Valley; the gars, Lepisosteus (garpike), of eastern North America; and the Figure 6: Bowfin teleosts or modern fishes. The teleosts have evolved into a variety of body forms today. They have a symmetrical caudal fin and a swim bladder (for hydrostatic functions) that Figure 7: Garpike has lost its connection to the digestive tract. Figure 8: Teleosts (a) Tilapia (b) Catfish (c) Sardines (d) African pike (e) Mormyrid (f) Flatfish AOE 4 BONY FISHES (OSTEICHTHYES: CLASS SARCOPTERYGII AND CLASS ACTINOPTERYGII) MODULE 8 Unit 4 Success of Bony Fishes Bony fishes have adapted themselves to nearly every available aquatic habitat. The remarkable success of bony fishes has resulted from a series of significant adaptations that have enabled them to dominate life in water. These include the swim bladder, lateral line system and gill cover. 1. Swim bladder: possession of swim bladder keeps bony fishes buoyant despite the fact that bones are heavier than cartilaginous skeleton. The swim bladder is a gas-filled sac that allows them to regulate their buoyant density and so remain suspended in water effortlessly at any depth. In most of today’s bony fishes, the swim bladder is an independent organ that is filled and drained of gases, mostly nitrogen and oxygen internally. It turns out that the gases are released from their blood. The gas flow is regulated by lactic acid, the acidity of which drives nitrogen out of the blood. The lower pH also alters the shape of the haemoglobin so that it is less able to bind oxygen. 2. Lateral line system: bony fishes possess a fully developed lateral line system, which consist of a series of sensory organs that project into a canal beneath the surface of the skin. Movement of water past the fish forces water through the canal. The sensory organs are deflected by the slightest movement of water over them. Nerve impulses from these sensory organs permit the fish to assess its rate of movement through water, sensing the movement as pressure waves against its lateral line. The lateral line enables a fish to detect motionless objects at a distance by the movement of water reflected off the object. In a very real sense, this is the fish equivalent of hearing. 3. Gill cover: most bony fishes have a hard plate, called the operculum, covering the gills on each side of the head. Flexing the operculum permits bony fishes to pump water over gills. When the mouth is open, the operculum is closed thereby sealing off the exit. This increases the volume of the mouth cavity so that the water is drawn into the mouth. When the mouth is closed, the operculum opens thereby decreasing the volume of the mouth cavity, forcing water past the gills to the outside. AOE 5 BONY FISHES (OSTEICHTHYES: CLASS SARCOPTERYGII AND CLASS ACTINOPTERYGII) MODULE 8 Unit 5 Biology of Bony Fish Teleosts have internal skeleton almost completely ossified. They have developed thin cycloid scales from the thick, ganoid type of earlier fishes. There is also the absence of spiracles. Locomotion The streamlined shape of a fish and the mucoid secretions that lubricates its body surface reduce friction between the fish and the water. The buoyant properties of water also contribute to the efficiency of a fish swimming through the water. The propulsive mechanism of a fish is its trunk and tail musculature. The musculature is composed of zig-zag muscle bands (myotomes). The slimy surface of a fish reduces water friction by at least 66% as compared with the same surface from which the slime has been removed. Nutrition and the Digestive System Most fishes are carnivores that prey on various animal foods from zooplankton and insect larvae to large vertebrates.
Load more

Recommended publications
  • O2 Secretion in the Eye and Swimbladder of Fishes
    1641 The Journal of Experimental Biology 209, 1641-1652 Published by The Company of Biologists 2007 doi:10.1242/jeb.003319 Historical reconstructions of evolving physiological complexity: O2 secretion in the eye and swimbladder of fishes Michael Berenbrink School of Biological Sciences, The University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7ZB, UK e-mail: [email protected] Accepted 12 March 2007 Summary The ability of some fishes to inflate their compressible value of haemoglobin. These changes predisposed teleost swimbladder with almost pure oxygen to maintain neutral fishes for the later evolution of swimbladder oxygen buoyancy, even against the high hydrostatic pressure secretion, which occurred at least four times independently several thousand metres below the water surface, has and can be associated with increased auditory sensitivity fascinated physiologists for more than 200·years. This and invasion of the deep sea in some groups. It is proposed review shows how evolutionary reconstruction of the that the increasing availability of molecular phylogenetic components of such a complex physiological system on a trees for evolutionary reconstructions may be as important phylogenetic tree can generate new and important insights for understanding physiological diversity in the post- into the origin of complex phenotypes that are difficult to genomic era as the increase of genomic sequence obtain with a purely mechanistic approach alone. Thus, it information in single model species. is shown that oxygen secretion first evolved in the eyes of fishes, presumably for improved oxygen supply to an Glossary available online at avascular, metabolically active retina. Evolution of this http://jeb.biologists.org/cgi/content/full/210/9/1641/DC1 system was facilitated by prior changes in the pH dependence of oxygen-binding characteristics of Key words: oxygen secretion, Root effect, rete mirabile, choroid, haemoglobin (the Root effect) and in the specific buffer swimbladder, phylogenetic reconstruction.
    [Show full text]
  • Opinion Why Do Fish School?
    Current Zoology 58 (1): 116128, 2012 Opinion Why do fish school? Matz LARSSON1, 2* 1 The Cardiology Clinic, Örebro University Hospital, SE -701 85 Örebro, Sweden 2 The Institute of Environmental Medicine, Karolinska Institute, SE-171 77 Stockholm, Sweden Abstract Synchronized movements (schooling) emit complex and overlapping sound and pressure curves that might confuse the inner ear and lateral line organ (LLO) of a predator. Moreover, prey-fish moving close to each other may blur the elec- tro-sensory perception of predators. The aim of this review is to explore mechanisms associated with synchronous swimming that may have contributed to increased adaptation and as a consequence may have influenced the evolution of schooling. The evolu- tionary development of the inner ear and the LLO increased the capacity to detect potential prey, possibly leading to an increased potential for cannibalism in the shoal, but also helped small fish to avoid joining larger fish, resulting in size homogeneity and, accordingly, an increased capacity for moving in synchrony. Water-movements and incidental sound produced as by-product of locomotion (ISOL) may provide fish with potentially useful information during swimming, such as neighbour body-size, speed, and location. When many fish move close to one another ISOL will be energetic and complex. Quiet intervals will be few. Fish moving in synchrony will have the capacity to discontinue movements simultaneously, providing relatively quiet intervals to al- low the reception of potentially critical environmental signals. Besides, synchronized movements may facilitate auditory grouping of ISOL. Turning preference bias, well-functioning sense organs, good health, and skillful motor performance might be important to achieving an appropriate distance to school neighbors and aid the individual fish in reducing time spent in the comparatively less safe school periphery.
    [Show full text]
  • Updated Checklist of Marine Fishes (Chordata: Craniata) from Portugal and the Proposed Extension of the Portuguese Continental Shelf
    European Journal of Taxonomy 73: 1-73 ISSN 2118-9773 http://dx.doi.org/10.5852/ejt.2014.73 www.europeanjournaloftaxonomy.eu 2014 · Carneiro M. et al. This work is licensed under a Creative Commons Attribution 3.0 License. Monograph urn:lsid:zoobank.org:pub:9A5F217D-8E7B-448A-9CAB-2CCC9CC6F857 Updated checklist of marine fishes (Chordata: Craniata) from Portugal and the proposed extension of the Portuguese continental shelf Miguel CARNEIRO1,5, Rogélia MARTINS2,6, Monica LANDI*,3,7 & Filipe O. COSTA4,8 1,2 DIV-RP (Modelling and Management Fishery Resources Division), Instituto Português do Mar e da Atmosfera, Av. Brasilia 1449-006 Lisboa, Portugal. E-mail: [email protected], [email protected] 3,4 CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal. E-mail: [email protected], [email protected] * corresponding author: [email protected] 5 urn:lsid:zoobank.org:author:90A98A50-327E-4648-9DCE-75709C7A2472 6 urn:lsid:zoobank.org:author:1EB6DE00-9E91-407C-B7C4-34F31F29FD88 7 urn:lsid:zoobank.org:author:6D3AC760-77F2-4CFA-B5C7-665CB07F4CEB 8 urn:lsid:zoobank.org:author:48E53CF3-71C8-403C-BECD-10B20B3C15B4 Abstract. The study of the Portuguese marine ichthyofauna has a long historical tradition, rooted back in the 18th Century. Here we present an annotated checklist of the marine fishes from Portuguese waters, including the area encompassed by the proposed extension of the Portuguese continental shelf and the Economic Exclusive Zone (EEZ). The list is based on historical literature records and taxon occurrence data obtained from natural history collections, together with new revisions and occurrences.
    [Show full text]
  • Notes on the Swim-Bladder Physiology of Cod (Gadus Morhua) Investigated from the Underwater Laboratory "Helgoland"
    Helgol~inder wiss. Meeresunters. 29, 460-463 (1977) Notes on the swim-bladder physiology of cod (Gadus morhua) investigated from the underwater laboratory "Helgoland" G. SUNDNES, B. GULLIKSEN ~X~ J. MORK Biological stasjon; Trondheim, Norway ABSTRACT: In situ sampling of gas from cod swim-bladders took place during a fortnight's saturation mission with the underwater laboratory "Helgoland" in May-June I975. These samples were compared to those done by the conventional method of transporting the fish to the surface for sampling. Based upon these in-situ measurements, the mean O2-concentration was 55.7 °/0 in buoyant cod at 15 m depth. Repeated sampling of the same fish showed a change in gas composition. Compared to the conventional method of transporting fish for sampling to the surface, in-situ sampling gave results with less variation, and indicated that surface-sampling does not give the correct gas composition of buoyant fish at depth of catch. INTRODUCTION Physiological investigations of fish swim-bladder have usually been performed near the surface, i.e. at about one atmosphere pressure. It means that fish were usually brought to the surface from their natural habitat of high water pressure to reduced pressure before experiments were performed and samples taken. Even in experiments with fish in pressure chambers, the gas samples of the swim-bladder were taken at one atmosphere pressure. Gas sampIes from fish at the depth of buoyancy have rarely been reported. The development of the underwater laboratory has given marine biologists a better opportunity to work under hydrostatic pressure whereby fish are kept under "natural" experimental conditions.
    [Show full text]
  • A Guide to the Parasites of African Freshwater Fishes
    A Guide to the Parasites of African Freshwater Fishes Edited by T. Scholz, M.P.M. Vanhove, N. Smit, Z. Jayasundera & M. Gelnar Volume 18 (2018) Chapter 2.1. FISH DIVERSITY AND ECOLOGY Martin REICHARD Diversity of fshes in Africa Fishes are the most taxonomically diverse group of vertebrates and Africa shares a large portion of this diversity. This is due to its rich geological history – being a part of Gondwana, it shares taxa with the Neotropical region, whereas recent close geographical affnity to Eurasia permitted faunal exchange with European and Asian taxa. At the same time, relative isolation and the complex climatic and geological history of Africa enabled major diversifcation within the continent. The taxonomic diversity of African freshwater fshes is associated with functional and ecological diversity. While freshwater habitats form a tiny fraction of the total surface of aquatic habitats compared with the marine environment, most teleost fsh diversity occurs in fresh waters. There are over 3,200 freshwater fsh species in Africa and it is likely several hundreds of species remain undescribed (Snoeks et al. 2011). This high diversity and endemism is likely mirrored in diversity and endemism of their parasites. African fsh diversity includes an ancient group of air-breathing lungfshes (Protopterus spp.). Other taxa are capable of breathing air and tolerate poor water quality, including several clariid catfshes (e.g., Clarias spp.; Fig. 2.1.1D) and anabantids (Ctenopoma spp.). Africa is also home to several bichir species (Polypterus spp.; Fig. 2.1.1A), an ancient fsh group endemic to Africa, and bonytongue Heterotis niloticus (Cuvier, 1829) (Osteoglossidae), a basal actinopterygian fsh.
    [Show full text]
  • Fishes Scales & Tails Scale Types 1
    Phylum Chordata SUBPHYLUM VERTEBRATA Metameric chordates Linear series of cartilaginous or boney support (vertebrae) surrounding or replacing the notochord Expanded anterior portion of nervous system THE FISHES SCALES & TAILS SCALE TYPES 1. COSMOID (most primitive) First found on ostracaderm agnathans, thick & boney - composed of: Ganoine (enamel outer layer) Cosmine (thick under layer) Spongy bone Lamellar bone Perhaps selected for protection against eurypterids, but decreased flexibility 2. GANOID (primitive, still found on some living fish like gar) 3. PLACOID (old scale type found on the chondrichthyes) Dentine, tooth-like 4. CYCLOID (more recent scale type, found in modern osteichthyes) 5. CTENOID (most modern scale type, found in modern osteichthyes) TAILS HETEROCERCAL (primitive, still found on chondrichthyes) ABBREVIATED HETEROCERCAL (found on some primitive living fish like gar) DIPHYCERCAL (primitive, found on sarcopterygii) HOMOCERCAL (most modern, found on most modern osteichthyes) Agnatha (class) [connect the taxa] Cyclostomata (order) Placodermi Acanthodii (class) (class) Chondrichthyes (class) Osteichthyes (class) Actinopterygii (subclass) Sarcopterygii (subclass) Dipnoi (order) Crossopterygii (order) Ripidistia (suborder) Coelacanthiformes (suborder) Chondrostei (infra class) Holostei (infra class) Teleostei (infra class) CLASS AGNATHA ("without jaws") Most primitive - first fossils in Ordovician Bottom feeders, dorsal/ventral flattened Cosmoid scales (Ostracoderms) Pair of eyes + pineal eye - present in a few living fish and reptiles - regulates circadian rhythms Nine - seven gill pouches No paired appendages, medial nosril ORDER CYCLOSTOMATA (60 spp) Last living representatives - lampreys & hagfish Notochord not replaced by vertebrae Cartilaginous cranium, scaleless body Sea lamprey predaceous - horny teeth in buccal cavity & on tongue - secretes anti-coaggulant Lateral Line System No stomach or spleen 5 - 7 year life span - adults move into freshwater streams, spawn, & die.
    [Show full text]
  • Phylogeny of Basal Tetrapoda
    Stuart S. Sumida Biology 342 Phylogeny of Basal Tetrapoda The group of bony fishes that gave rise to land-dwelling vertebrates and their descendants (Tetrapoda, or colloquially, “tetrapods”) was the lobe-finned fishes, or Sarcopterygii. Sarcoptrygii includes coelacanths (which retain one living form, Latimeria), lungfish, and crossopterygians. The transition from sarcopterygian fishes to stem tetrapods proceeded through a series of groups – not all of which are included here. There was no sharp and distinct transition, rather it was a continuum from very tetrapod-like fishes to very fish-like tetrapods. SARCOPTERYGII – THE LOBE-FINNED FISHES Includes •Actinista (including Coelacanths) •Dipnoi (lungfishes) •Crossopterygii Crossopterygians include “tetrapods” – 4- legged land-dwelling vertebrates. The Actinista date back to the Devonian. They have very well developed lobed-fins. There remains one livnig representative of the group, the coelacanth, Latimeria chalumnae. A lungfish The Crossopterygii include numerous representatives, the best known of which include Eusthenopteron (pictured here) and Panderichthyes. Panderichthyids were the most tetrapod-like of the sarcopterygian fishes. Panderichthyes – note the lack of dorsal fine, but retention of tail fin. Coelacanths Lungfish Rhizodontids Eusthenopteron Panderichthyes Tiktaalik Ventastega Acanthostega Ichthyostega Tulerpeton Whatcheeria Pederpes More advanced amphibians Tiktaalik roseae – a lobe-finned fish intermediate between typical sarcopterygians and basal tetrapods. Mid to Late Devonian; 375 million years old. The back end of Tiktaalik’s skull is intermediate between fishes and tetrapods. Tiktaalik is a fish with wrist bones, yet still retaining fin rays. The posture of Tiktaalik’s fin/limb is intermediate between that of fishes an tetrapods. Coelacanths Lungfish Rhizodontids Eusthenopteron Panderichthyes Tiktaalik Ventastega Acanthostega Ichthyostega Tulerpeton Whatcheeria Pederpes More advanced amphibians Reconstructions of the basal tetrapod Ventastega.
    [Show full text]
  • Class Wars: Chondrichthyes and Osteichthyes Dominance in Chesapeake Bay, 2002-2012
    Class Wars: Chondrichthyes and Osteichthyes dominance in Chesapeake Bay, 2002-2012. 01 July 2013 Introduction The objective of this analysis was to demonstrate a possible changing relationship between two Classes of fishes, Osteichthyes (the bony fishes) and Chondrichthyes (the cartilaginous fishes) in Chesapeake Bay based on 11 years of monitoring. If any changes between the two Classes appeared to be significant, either statistically or anecdotally, the data were explored further in an attempt to explain the variation. The Class Osteichthyes is characterized by having a skeleton made of bone and is comprised of the majority of fish species worldwide, while the Chondrichthyes skeleton is made of cartilage and is represented by the sharks, skates, and rays (the elasmobranch fishes) and chimaeras1. Many shark species are generally categorized as apex predators, while skates and rays and some smaller sharks can be placed into the mesopredator functional group (Myers et al., 2007). By definition, mesopredators prey upon a significant array of lower trophic groups, but also serve as the prey base for apex predators. Global demand for shark and consequential shark fishing mortality, estimated at 97 million sharks in 2010 (Worm et al., 2013), is hypothesized to have contributed to the decline of these apex predators in recent years (Baum et al., 2003 and Fowler et al., 2005), which in turn is suggested to have had a cascading effect on lower trophic levels—an increase in mesopredators and subsequent decrease in the prey base (Myers et al., 2007). According to 10 years of trawl survey monitoring of Chesapeake Bay, fish species composition of catches has shown a marked change over the years (Buchheister et al., 2013).
    [Show full text]
  • Macrogyrodactylus Polypteri Malberg on Polypterus Senegalus in the Sudan
    Macrogyrodactylus polypteri Malberg on Polypterus senegalus in the Sudan Item Type article Authors Amirthalingam, C. Download date 26/09/2021 20:17:20 Link to Item http://hdl.handle.net/1834/32496 NOTES AND COMMENTS Macrogyrodactylus polypter£ Malberg on Polypterus senega/us in the Sudan POLYPTERUS is a genua of fishes which is best considered as descendent ()f the Palaeoniscid stock coming from Devonian times (400 million years ago). This genus, one of the' indigenous fishes of Africa, is of economic importance in some parts of the Sudan. In August 1962, small specimens of Polypterus senegalus Cuvier, ranging from 20 to 25 ems., collected from Jebel el Aulia on the While Nile, were introduced into a well aerated aquarium and fed on earthworms. During the first week the water was clear in the tank; nevertheless, because of the debris from the earthworms, the water was changed once or twice. The fishes appeared to be quite active and healthy and were swimming in mid-water or resting on the fl.oor of the aquarium. Occasionally they came up to the surface to take a gulp of air. In the course of the following week, the water-although changed as frequently as before-appeared to become turbid and viscous. At the end of that week, a few of the fishes were found to be lethargic, drifting with the dorsal finlets and a row or two of the dorsolateral scales exposed above the water level. On the 15th day some died. Post-mortem examination revealed that the dead fishes were heavily infected with a monogenetic trematode of the Gyrodactylid type which was later identified (by my colleague L.
    [Show full text]
  • Systematic Morphology of Fishes in the Early 21St Century
    Copeia 103, No. 4, 2015, 858–873 When Tradition Meets Technology: Systematic Morphology of Fishes in the Early 21st Century Eric J. Hilton1, Nalani K. Schnell2, and Peter Konstantinidis1 Many of the primary groups of fishes currently recognized have been established through an iterative process of anatomical study and comparison of fishes that has spanned a time period approaching 500 years. In this paper we give a brief history of the systematic morphology of fishes, focusing on some of the individuals and their works from which we derive our own inspiration. We further discuss what is possible at this point in history in the anatomical study of fishes and speculate on the future of morphology used in the systematics of fishes. Beyond the collection of facts about the anatomy of fishes, morphology remains extremely relevant in the age of molecular data for at least three broad reasons: 1) new techniques for the preparation of specimens allow new data sources to be broadly compared; 2) past morphological analyses, as well as new ideas about interrelationships of fishes (based on both morphological and molecular data) provide rich sources of hypotheses to test with new morphological investigations; and 3) the use of morphological data is not limited to understanding phylogeny and evolution of fishes, but rather is of broad utility to understanding the general biology (including phenotypic adaptation, evolution, ecology, and conservation biology) of fishes. Although in some ways morphology struggles to compete with the lure of molecular data for systematic research, we see the anatomical study of fishes entering into a new and exciting phase of its history because of recent technological and methodological innovations.
    [Show full text]
  • History of Fishes - Structural Patterns and Trends in Diversification
    History of fishes - Structural Patterns and Trends in Diversification AGNATHANS = Jawless • Class – Pteraspidomorphi • Class – Myxini?? (living) • Class – Cephalaspidomorphi – Osteostraci – Anaspidiformes – Petromyzontiformes (living) Major Groups of Agnathans • 1. Osteostracida 2. Anaspida 3. Pteraspidomorphida • Hagfish and Lamprey = traditionally together in cyclostomata Jaws = GNATHOSTOMES • Gnathostomes: the jawed fishes -good evidence for gnathostome monophyly. • 4 major groups of jawed vertebrates: Extinct Acanthodii and Placodermi (know) Living Chondrichthyes and Osteichthyes • Living Chondrichthyans - usually divided into Selachii or Elasmobranchi (sharks and rays) and Holocephali (chimeroids). • • Living Osteichthyans commonly regarded as forming two major groups ‑ – Actinopterygii – Ray finned fish – Sarcopterygii (coelacanths, lungfish, Tetrapods). • SARCOPTERYGII = Coelacanths + (Dipnoi = Lung-fish) + Rhipidistian (Osteolepimorphi) = Tetrapod Ancestors (Eusthenopteron) Close to tetrapods Lungfish - Dipnoi • Three genera, Africa+Australian+South American ACTINOPTERYGII Bichirs – Cladistia = POLYPTERIFORMES Notable exception = Cladistia – Polypterus (bichirs) - Represented by 10 FW species - tropical Africa and one species - Erpetoichthys calabaricus – reedfish. Highly aberrant Cladistia - numerous uniquely derived features – long, independent evolution: – Strange dorsal finlets, Series spiracular ossicles, Peculiar urohyal bone and parasphenoid • But retain # primitive Actinopterygian features = heavy ganoid scales (external
    [Show full text]
  • Growth and Reproductive Parameters of Polypterus Senegalus Cuvier 1829 in Eleiyele Lake
    New York Science Journal 2016;9(11) http://www.sciencepub.net/newyork Growth and reproductive parameters of Polypterus senegalus Cuvier 1829 in Eleiyele Lake Adedolapo Abeke Ayoade and Juliet Avwesuruo Akponine Department of Zoology, University of Ibadan, Oyo State, Nigeria. *Corresponding author E-mail: [email protected] Phone Number: +234-8033855807 Abstract: The Senegal bichir, Polypterus senegalus Cuvier 1829 is of commercial importance as food and ornamental fish. This study describes the growth pattern and aspects of reproductive biology for the species in the Eleyele Lake, Nigeria. One hundred and twenty nine specimens were collected from October, 2010 to April, 2011. For each individual, the total length, standard length and body weight were measured also aspects of reproductive biology (gonadosomatic index, fecundity, egg diameter) were determined. All the LWRs showed strong correlations (r> 0.75, p>0.05). The b value obtained varies with body size and higher value was recorded for the smaller size group. The mean K for the combined sexes was 0.536 0.007. Absolute fecundity ranged between 622 (for specimen with TL = 16.4 cm; total weight = 21.61 g) and 2593 eggs (for specimen with TL = 27.7 cm; total weight = 120.62 g). The frequency polygons of the egg diameter suggest the species is a multiple spawner. [Adedolapo Abeke Ayoade and Juliet Avwesuruo Akponine. Growth and reproductive parameters of Polypterus senegalus Cuvier 1829 in Eleiyele Lake. N Y Sci J 2016;9(11):27-31]. ISSN 1554-0200 (print); ISSN 2375-723X (online). http://www.sciencepub.net/newyork. 5. doi:10.7537/marsnys091116.05.
    [Show full text]