Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash...
Transcript of Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash...
![Page 1: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/1.jpg)
Lecture 3 - Early Fishes
1. Early Chordates
2. Conodonts
3. Early Vertebrates
4. Jawless fishes
5. Agnatha/ Gnathostomes junction
6. Placoderms
7. Chondrichthyes
![Page 2: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/2.jpg)
most primitivechordates?
Early Chordates
Urochordates(tunicates and salps)
Cephalochordates(lancelets)
notochord: stiffening rod that provides support• crucial to vertebrate
embryological development
- lack vertebrae, brain, image forming eyes, & heart
![Page 3: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/3.jpg)
Cephalochordates are sister to vertebrates • embrace your inner lancelet!
![Page 4: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/4.jpg)
Craniata (= Vertebrates)Synapomorphies:Cranium present
Cartilage or bone or both are present
Heart chambered
Neural crests
![Page 5: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/5.jpg)
Conodonts
• 600 – 200 mybp
• “elements” were abundant in fossil beds
• Not until 1980’s did we find fossilized soft body parts
• cartilaginous head skeleton
![Page 6: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/6.jpg)
Agnatha - Jawless Fishes
Agnatha • appeared 530 mybp• previously given superclass
status• now recognized as
paraphyletic• Myxinomorphs now
considered separate in own superclass
• still used as informal adjective for jawless fishes
![Page 7: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/7.jpg)
Agnatha – Ostracoderms
• Name means “shell-skinned” referring to bony shield that covered head and thorax
• heavily armored
• first ossified bones evolve
• jawless & no pelvic fin
![Page 8: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/8.jpg)
Ostracoderms are paraphyletic
…making “ostracoderm” a false designation
• likely 4 superclasses of jawless fishes
![Page 9: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/9.jpg)
Hagfishes - Class Myxini
81 speciesLive deep – scavengers & predatorsStrictly marine• isoosmotic - no osmoregulation
![Page 10: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/10.jpg)
Hagfishes - Class Myxini
• 4 rudimentary hearts
• 70-200 pairs of slime glands
• eye spots
• lack vertebrae
![Page 11: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/11.jpg)
Rasping tongue
![Page 12: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/12.jpg)
Hagfish feeding
![Page 13: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/13.jpg)
Hagfishes - Class MyxiniReproduction….?• cash prize for information on the reproduction of
Myxine glutinosa remains unclaimed since 1854 from the Royal Danish Academy of Sciences
Development• No larval stage, direct development
from eggs
![Page 14: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/14.jpg)
Lampreys - Class Petromyzontida
~ 41 speciesOsmoregulate - found in freshwater and oceanLarval stage called ammocoeteAmmocoete undergo metamorphosis Ammocoete filter feeds
![Page 15: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/15.jpg)
Lampreys
![Page 16: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/16.jpg)
Lampreys
Reproduction• semelparous• males build nest • eggs hatch after 12-14 days and ammocoete
emerges• ammocoete burrows into mud or silt in river or
stream, with head emerged filter feeding• can stay like this for up to seven years
Non-parasitic spp.• form spp. pairs with parasitic spp.
![Page 17: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/17.jpg)
Agnatha - Gnathostomata Junction
Gnathostomes: jawed vertebrates
![Page 18: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/18.jpg)
Agnatha - Gnathostomata Junction
Gnathostomes: jawed vertebrates
![Page 19: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/19.jpg)
Agnatha - Gnathostomata Junction
Synapomorphies:
• Jaws modified from gill arches
• Paired limbs
• Vertebral centra usually present
Gnathostomes: jawed vertebrates
![Page 20: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/20.jpg)
![Page 21: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/21.jpg)
Previously thought that a shark like ancestor gave rise to all jawed vertebrates but this fossil debunks that hypothesis• characteristics of both Placoderms and Osteichthyans
![Page 22: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/22.jpg)
Entelognathus primordialis
![Page 23: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/23.jpg)
Entelognathus primordialis,
![Page 24: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/24.jpg)
Placoderms“Plate-skinned”
• fresh & salt water
• arose ~430 mybp
• disappeared ~350 mybp
![Page 25: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/25.jpg)
Synapomorphies:
Head and shoulder girdles with dermal bony plates
Five gill arches
Placoderms
- evolved towards reduced armament
![Page 26: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/26.jpg)
Chondrichthyes - Cartilaginous fishes• arose ~420 mybp
![Page 27: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/27.jpg)
Chondrichthyes - Cartilaginous fishes
• extant cartilaginous fishes
![Page 28: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/28.jpg)
Synapomorphies:
• Cartilaginous skeleton, not ossified
• Skull with no sutures
Chondrichthyes - Cartilaginous fishes
![Page 29: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/29.jpg)
Synapomorphies (cont’d):
• Internal fertilization with claspers
• High blood concentration of urea
Chondrichthyes - Cartilaginous fishes
![Page 30: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/30.jpg)
Reproduction
oviparous: lay eggs• ~40% species
viviparous: live birth• ~10% species• placental attachment
ovoviviparous: egg hatches internally and give live birth• ~50% species• ancestral state
Chondrichthyes - Cartilaginous fishes
![Page 31: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/31.jpg)
Split into two subclasses:
Elasmobranchii(sharks & rays)
Holocephali(ratfishes)
Chondrichthyes - Cartilaginous fishes
![Page 32: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/32.jpg)
Holocephali
• “whole-head”
• oviparous
![Page 33: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/33.jpg)
Holocephalans - Chimaeras - Ratfish
Synapomorphies:Gill cover over 4 gill openings
Upper jaw fused to cranium
![Page 34: Lecture 3 - Early Fishes...Jul 03, 2016 · Hagfishes - Class Myxini Reproduction….? • cash prize for information on the reproduction of Myxine glutinosa remains unclaimed since](https://reader033.fdocuments.us/reader033/viewer/2022060908/60a285f4fe5ef015a5252e59/html5/thumbnails/34.jpg)
Holocephalans - Chimaeras - Ratfish
- more speciose in the past
Some species possess head claspers