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Home , Basking shark, Chimaera, Holocephali, Sand shark

13.4.2016

ICHTHYOLOGY

CHONDRICHTHYES (, , rays, skates)

MILOSLAV PETRTÝL – [email protected]

CHONDR- (cartilage) + ICHTHYS ()

SHARK ATTACK IN NEWS HOW REAL IS THE RISK?!

• over 200 cases (50 lethal) unprovoked attack by great white …worldwide

In New York 10x more people is bitten by other people than sharks worldwide Long term statistics: 1 death by drown to 3,5 mil water activities 1 shark attack to 11,5 mil water activities

1995 - 2003 along costline of USA 1857 people killed by lightning. In the same period 740 shark attacks – 22 lethal. http://www.flmnh.ufl.edu/fish/sharks/statistics/trends.htm

SWIMMING SEASON IS COMING! RISK FOR THE SHARKS?! • Overfishing (70-100.000.000 sharks/year) • High demand for shark fin from Asian countries

Hamish Jolly – designer of „anti-shark suit“ video at: TED.com

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PHYLOGENY

CHONDRICHTHYES

Monophyletic group

Time scale divergence of groups Inoue et al. 2010 - Evolutionary Origin and Phylogeny of the Modern Holocephalans

EVOLUTION CHONDRICHTHYES

• Over 450 milion year of evolution (200 mil. Before dinosaur • Rare fissilization due to cartilage skeleton structure (except of teeth)

HOLOCEPHALI

• Hammerhead sharks (Sphyrnidae) are most are most advnaced Common ancestor

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SPECIES RICHNESS COMMON CHARACTERISTICS WORLD DISTRIBUTION • Water (marine) organisms • Cartilage (not real bones) • Rare fissilization except teeth • Hydrodynamic body, size range, 20 cm – 18 m • Body covered with plakoid scales (homologic with teeth) 30 sp. • Mostly 5 oponings (up to 7) Sharks 430 sp. • Internal fertilization Skates, rays 540 sp. • asymmetric „heterocercal“ caudal fin (tail)

(NELSON 2007)

Chimaeriformes PHYLOGENETIC TREE Heterodontiformes Orectolobiformes Pristiophoriformes Galeomorphi Squatiniformes Squalomorphi Hexanchiformes Neoselachii Echinorhiniformes Carcharhiniformes Squaleomorphi Squaliformes Lamniformes Elasmobranchii Galeomorphi Squatiniformes Orectolobiformes Pristiophoriformes Heterodontiformes Torpediniformes vymřelé bazální linie Pristiformes Batoidea

Stiassny et al. (1996) a Craft & Donoghue (2004)

SPECIES DETERMINATION

• Presence/absence of fin

• Shape and dimensions of fins

• Presence/absence of spines

• Presence/absence of

anal fin • Presence/absence of eye lid

• Size and position of jaws

• Number and size of gill openings

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a) HOLOCEPHALI family: 2 - 20: Chimaera, CHIMAERIFORMES Worldwide, ♂head clasper, toxic D spine ♂ • Absence of ribs, stomach and spiracle family: Callorhynchidae • Oviparious – similar to the shark egg (chimérovkovití) • „holocephali“ upper jaw joint firmly with the skull 1 - 4 South hemisphere • Sexual dimorfism (males: pterygopod, tentaculum) • Plate-like teeth (whole-life)

• Skiny family: (pachimérovití) • Poisonous spine 3 - 6: , , - worldwide

DISTRIBUTION Subclass - ELASMOBRANCHII

• Pacific, Atlantic a Indian ocean • Over 900 sp. Chondrichthyes • Temperate zone – tropical zone • Carcharhiniformes more than ½ of sharks, mostly sub- • Mostly below 200 m (depth) tropic and tropic • Pelagic types live in open ocean Lamniformes (mako, great white, , ) • Squaliformes deeper water of norhern hemisphere • Rays of group Rajoidei mostly in deeper waters • Myliobatoidei shallow water of tropics

Chimaera monstrosa callorynchus Rhinochimaera atlantica

Selachii – modern sharks WORLD DISTRIBUTION

• Continental shelf versus deep sea species • Torpedo-lie body shape • Elongated rostrum (head) • Lower (inferior) mouth • Mostly 5 gill openings

Centroscyllium fabricii Squalus acanthias

Zdroj: http://atlanticsharks.org

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Angelshark Longnose „great white“ Squatina squatina Pristiophorus cirratus

worldwide distribution (except antarctic/arctic)

: Rajiformes - Skates (Rajidae) REYS - BATOIDEA Two-parts pelvic fins Robust tail without spine Presence of bigger scales aligned along body in raws • Compressed, flattened body Little caudal fin

• Mostly benthic

• Lower mouth order: Myliobatiformes - Rays and stingrays (Dasytidae + Potamotrigonidae) One-part pelvic fins • Mostly 5 gill openings Narrow elongated tail with spine Absence of bigger scales aligned along body in raws Often bright colors on body • Bigger visible spiracle

What is „FISH“ JAWLESSS Cartilaginous ANATOMY - PHYSIOLOGY

JAWED Cartilaginous Bony

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GENERAL ANATOMY OF GENERAL ANATOMY ‐ shark

Lampreys

Elasmobranchs Shark+skates

Cartilaginous skelet Strong jaw Pelvic and pectoral fins are paired Scales - placoid Reproduction organ of male 5-7 gill openings Developed senses Bony fish One or two dorsal fins Heterocercal caudal fin

CARTILAGINOUS SKELETON

CARTILAGINOUS SKELETON CARTILAGINOUS SKULL • neurocranium • heterocerkal tail (caudal fin) • viscerocranium • Jaws consits of pair cartilage • Caudal fin is the „engin“ for motion upper=palatoquadratum • Pair limbs with inner skeleton lower=mandibulare

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Expected morpho-evolution of jaws from arches SKULL - JAWS • Shape of teeth – function for biting and cutting (chop) • Robust heavy head – dynamic biting

Common ancestor with 9 gill arches - 3. a 4. become in shape of jaws • Hyostilic skull – protrusion of jaws from to skull

INTERNAL ANATOMY INTERNAL ANATOMY

INTERNAL ANATOMY INTERNAL ANATOMY

MALE MALE

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INTERNAL ANATOMY BLOOD CIRCULATION • Only one circuit (whole body) • Four-part heart FEMALE

The McGraw-Hill Companies, 2009

DIGESTIVE TRACT RESPIRATION • Respiration and swimming •„SPIRAL VALVE“ • Through the mouth (sharks) • Through the spiracle (rays) 7 4 4

SENSES 2/3 of brain capacity serves for perception

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smell – drop of blood in the swimming • Hearing 10 - 800 Hz (human 20-20.000 Hz). pool „stereo-smell“ • Electroreceptors – Lorenzi ampule, Sight – long-sighted sense of bioelectric field of pray tapetum lucidum improved night vision

Eye lens is spherical – focusing by its movement Second lid – for protection (predator, prey defense) • Mechanoreceptory lateral line

ELECTRIC FIELD LOCOMOTION – MOVEMENT - SHAPE

Torpediniformes – 60 species • Swimming muscles are attached to elastic skin – that 30 amper with 50 - 200 volts (eq. of hair dryer) makes effect of rubber band. It makes swimming easier Adapted muscle tissue (saving of energy).

• Asymmetric vs symmetric tail • mako, great white) similar body shape as pelagic predátory fish (tuna) (55 km/h)

• Extrémní asymmetry in tresher shark

• Flat body of rays and skates – bentic species

CAUDAL FIN - TAILS STRATEGIE „NULOVÉ HMOTNOSTI“

• Absence of gass bladder + enlarged filled with oil (squalen) – 25% of total body mass – 4 m shark has 80 litres of oil – 9 m shark has over 2000 litres • Density (in comparison with water) • Compressiblity – very low (like water)

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WHY TO EAT SHARK LIVER METABOLISM

• 90 tabs 30EUR • Slow metabolism in comparison with (bony fishes) • Fish needs 2-3x more of oxygen and 4x more of food. • „lazy“ benthic species – vs. termoregulation of pelagic sp. • Slow growht vs life span (up to 60 years) hard to estimate the age when bone is absent

OSMOREGULATION ISOOSMOTIC SHARKS

• Hypoosmotic sea fish • Isoosmotic sharks holds part of urine and TMAO (trimetylaminoxid) in body tissue (blood). They don‘t need to dring water!!

• Smell of dead shark 

ENVIRONMENT - HABITAT

• Mostly marine ECOLOGY - ETHOLOGY • Some in freshwater Potamotrygoninae a Dasyatidae. • Bullshark (Carcharhinus leucas) and saw-fish (Pristis perotteti)

• Mostly up to 200m, some in deeper water (up to 4000m). • In general in deeper water is lack of Zeb Hogan food. Resources are restricted.

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FOOD SPECIALISATION FOOD SPECIALISATION 1) OPEN-WATER HUNTER (, , Alpias, • 4 types of teeth – regarding the food (pray) Squalus, , Carcharodon) • Some species up to 30 000 teeth during lifetime.

2) -FEEDER (Cetorhinus, Rhincodon, rejnoci- Myliobatidae)

3) BENTHIC PREDATOR (Heterodontus, Scyliorhinus, Pristiophorus, Squatina, většina rejnoků)

FOOD SPECIALISATION REPRODUCTION

• Internal fertilization – vivparous or oviparous • Hunting technique • Male reproduction organ – pterygopods = claspers –Saw-fish –Elektricray – Thresher shark – Manta – – Basking shark

40% ovoparous – ancestral reproduction type REPRODUCTION Pregnancy up to 24 m just a few offsprings = K-strategy

Eggs of sharks and rays Egg of chimaera

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REPRODUCTION REPRODUCTION

– oophagye – (thresher, mako, great-white) – embryophagye – () – Placental feeding - Carcharhinidae, Sphyrnidae (mammal like!!) – Uterine fluid Myliobatoidae, manta (milk-like substance)

• Females with 3x thicker skin than males

SIZE – MYTH AND REALITY REPRODUCTION • „Virgin birth“ – facultativve partenogenesis of sharks?? • Extinct Carcharodon ?! (30/15m)

• Sphyrna tiburo in captivity Chapman, D. D., Shivji, M. S., Louis, E., Sommer, J., Fletcher, H., & Prodöhl, P. A. (2007). Virgin birth in a hammerhead shark. Biology letters,3(4), 425-427. 18 cm •Saw-fish(Pristis pectinata) Fields, A. T., Feldheim, K. A., Poulakis, G. R., & Chapman, D. D. (2015). Facultative parthenogenesis in a critically endangered wild . Current Biology, 25(11), R446-R447.

Reconstruction by Bashford Dean in 1909 https://commons.wikimedia.org/w/index.php?curid=25031119 https://commons.wikimedia.org/w/index.php?curid=4387521

SIZE

Etmopterus perryi (20 cm, 150g) dwarf shark Rhincodon typus (18 m, 12 t), biggest „fish“

Bigger body is safer (protection against predators)

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SIZE PLANKTON FEEDER • 12-16m/20 t • Biggest white shark female: 6,4 m, 3312 kg • Cuba, 1945

RARITY REFERENCES • Gaisler, Zima: Zoologie Obratlovců brasiliensis •Roček: Historie obratlovců Bioluminiscence, spoon-like bite • Holtz Thomas: www.geol.umd.edu/~tholtz/ 15-19 cm • www.Wikipedia.org The smalliest one • www.fishbase.org Lamniformes „homoiothermy“ • www.amnh.org/learn/pd/sharks_rays • www.elasmo-research.org/ Life-span – 70+ Squalus acanthias () • www.tolweb.org/tree/ Speed - Isurus oxyrinchus 55km/h • www.shark.ch • www.palaeos.com Bioluminiscence: Etmopterus spinax, • http://www.elasmodiver.com/ pelagios

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