Fishes part 1 - Pisces

Class Pisces

• Evolution of fishes happened mainly through the development of WHAT. Therefore, the fishes are considered the earliest WHAT.

• Gnathostomes translates as “WHAT”.

• Earliest fishes are known from the WHAT, and they evolved from WHAT ancestors.

Class Pisces

• Evolution of fishes happened mainly through the development of JAWS. Therefore, the fishes are considered the earliest GNATHOSTOMES.

• Gnathostomes translates as “JAWED MOUTH”.

• Earliest fishes are known from the MIDDLE SILURIAN, and they evolved from AGNATHAN ancestors.

Class Pisces

• Aquatic vertebrates adapted to WHAT, WHAT and WHAT environments.

Class Pisces

• Aquatic vertebrates adapted to MARINE, BRACKISH and FRESHWATER environments.

Class Pisces

• Respiration is mostly through WHAT, but some taxa evolved WHAT-like structures and were/are capable to breath WHAT oxygen.

Class Pisces

• Respiration is mostly through GILLS, but some taxa evolved LUNG-like structures and were/are capable to breath ATMOSPHERIC oxygen.

Class Pisces

• Reproduction is mainly through numerous WHAT

Class Pisces

• Reproduction is mainly through numerous UNPROTECTED EGGS

Class Pisces

• High magnitude WHAT variability

• Some species are capable to live WHAT and other evolved WHAT capabilities over relatively short distances

• The diversity is extremely high, and more than 35 orders are recognized in the modern faunas

Class Pisces

• High magnitude MORPHOLOGICAL variability

• Some species are capable to live INLAND and other evolved FLIGHT capabilities over relatively short distances

• The diversity is extremely high, and more than 35 orders are recognized in the modern faunas

Find fishes through WHAT, WHAT or WHAT

Find fishes through TEETH, SCALES or BONY PLATES

Otoliths = WHAT

Otoliths = Mineralized parts of the internal ear used for body balance

Subclass Acanthodii

• The body has a general aspect resembling the WHAT; informally, they were called ‘WHAT’.

• WHAT – WHAT

• The skeleton is mostly WHAT, seemingly indicating a primitive nature.

Subclass Acanthodii

• The body has a general aspect resembling the SHARKS; informally, they were called ‘SPINY SHARKS’.

• MIDDLE SILURIAN – LOWER PERMIAN.

• The skeleton is mostly CARTILAGINOUS, seemingly indicating a primitive nature.

Subclass Acanthodii

• The paired fins (WHAT and WHAT) present a WHAT base.

• One anterior bony spine occurs both in the WHAT and WHAT fins.

• The body is covered by WHAT but never evolved a WHAT.

• They have no WHAT

Subclass Acanthodii

• The paired fins (ABDOMINAL and PECTORALS) present a BONY base.

• One anterior bony spine occurs both in the PAIRED and UNPAIRED fins.

• The body is covered by SMALL SCALES but never evolved a CEPHALIC SHIELD.

• They have no SCALES

Acanthodii - Acanthodes

• Lower HWAT

• WHERE

Acanthodii - Acanthodes

• Lower PERMIAN

• Germany

Acanthodii - Diplacanthus

• middle WHAT

• WHERE

Acanthodii - Diplacanthus

• middle DEVONIAN

• Scotland

Acanthodii - Gyracanthus

• Upper WHAT

• WHERE

Acanthodii - Gyracanthus

• Upper CARBONIFEROUS

• England

Subclass Placodermi

• Placoderms are the most diverse and numerous fishes (dominant) of the WHAT.

• Stratigraphical range: WHAT – WHAT.

• Evolved a strong WHAT, which in some representatives extends over the WHAT fins.

Subclass Placodermi

• Placoderms are the most diverse and numerous fishes (dominant) of the DEVONIAN.

• Stratigraphical range: UPPERMOST SILURIAN – DEVONIAN.

• Evolved a strong CEPHALIC SHIELD, which in some representatives extends over the PECTORAL fins.

Subclass Placodermi

• In general, the placoderms present morphological resemblances with the WHAT and WHAT agnathans.

• Placoderms evolved probably from AGNATHAN ancestors.

• They were apex WHAT

• Placoderms are subdivided into two groups: WHAT and WHAT.

Subclass Placodermi

• In general, the placoderms present morphological resemblances with the OSTRACODERM and HETEROSTRACAN agnathans.

• Placoderms evolved probably from AGNATHAN ancestors.

• They were apex PREDATORS

• Placoderms are subdivided into two groups: ARTHRODIRES and ANTIARCHS.

Arthrodires

• Almost exclusively WHAT, rarely adapted to WHAT environments.

• Stratigraphical range: WHAT.

• Evolved a WHAT with plates connected in WHAT, which confer it a high levels of WHAT.

• Up to WHAT meters in length.

Arthrodires

• Almost exclusively MARINE, rarely adapted to FRESHWATER environments.

• Stratigraphical range: DEVONIAN.

• Evolved a CEPHALIC SHIELD with plates connected in POINTS, which confer it a high levels of FLEXIBILITY.

• Up to TEN meters in length.

WHAT - apex predator of the Athrodires

DUNKLEOSTEUS - apex predator of the Athrodires

Antiarchs

• Occur mostly in WHAT environments.

• The anterior part of the body is protected by a WHAT consisting of WHAT plates, which extend over the WHAT fins.

• WHAT swimmers in WHAT waters.

• Up to WHAT meters in length

Antiarchs

• Occur mostly in FRESHWATER environments.

• The anterior part of the body is protected by a CEPHALIC SHIELD consisting of ORNAMENTED plates, which extend over the PECTORAL fins.

• SLOW swimmers in SHALLOW waters.

• Up to TWO meters in length

Antiarch

WHAT - Devonian

Antiarch

COCCOSTEUS - Devonian

WHAT - Most frequent Antiarch in the fossil record

Bothriolepis - Most frequent Antiarch in the fossil record (Upper Devonian + Cananda)

WHAT - rare antiarch

Gemündina - rare antiarch

Subclass Chondrichthyes

• The group of fishes with the longest stratigraphical range: WHAT - WHAT.

• The skeleton is mostly WHAT, but the teeth are WHAT, and vertebrae can present an WHAT.

• Includes WHAT, WHAT and WHAT.

Subclass Chondrichthyes

• The group of fishes with the longest stratigraphical range: UPPER SILURIAN - HOLOCENE.

• The skeleton is mostly CARTILAGINOUS, but the teeth are BONY, and vertebrae can present an INCIPIENT OSSIFICATION.

• Includes SHARKS, CHIMAERAS and RAYS.

Subclass Chondrichthyes

• WHAT organisms, adapted to living within the WHAT or in the proximity of the WHAT (WHAT sharks).

• The modern representatives are exclusively WHAT, but in the geological past they adapted occasionally to WHAT environments.

Subclass Chondrichthyes

• NEKTIC organisms, adapted to living within the WATER COLUMN or in the proximity of the SUBSTRATE (BATHOID sharks).

• The modern representatives are exclusively MARINE, but in the geological past they adapted occasionally to FREASHWATER environments.

WHAT - freshwater shark

LEBACANTHUS - freshwater shark

WHAT and WHAT are bathoid sharks

Spathibatis and Squatina are bathoid sharks

Subclass Chondrichthyes

• The representatives of this group evolved probably from WHAT ancestors.

• Throughout their evolutionary history, the group remained quite conservative relative to the WHAT skeleton.

• The earliest diversification dates back in the WHAT times.

• Most WHAT fish today

Subclass Chondrichthyes

• The representatives of this group evolved probably from AGNATHAN ancestors.

• Throughout their evolutionary history, the group remained quite conservative relative to the CARTILAGINOUS skeleton.

• The earliest diversification dates back in the DEVONIAN times.

• Most DIVERSE fish today