Scientifically known as dipnoi, small order of fresh water species. Lung fish are recognized as living fossils. The unique adaptation of this fish having gills and lungs for respiration depending on the environmental conditions.
2. Department of Zoology
Topic:Lung fish
Presented by:Alishba Qirat
Roll #20M-UOC/ZOL-25
Subject: Ichthyology
Session: 2020-2024
Instructor Name:Dr.Syeda Nadia Ahmad
5. •Scientifically known as Dipnoi,small order of fresh
water bony fishes.
•Lung fish are recognized as living fossil’s.
•Fossil records reveal their evolutionary journey from
fish like ancestors to air breathing pioneers
•Their evolutionary history dates back to the early
Devonian Period
•They respire by gills and lungs (Jorgensen et al.,2022).
7. Fig.Genera of lung fish
https://cdn.britannica.com/80/55080-050-B63ED651/fossil-
forms-Dipnoi-fishes.jpg
8. Distribution
• Modern lung fish show discontinuous
distribution.
• The three surviving genera of lung fishes are
Neoceratodus,protopterus and Lepidosiren,all are
inhabitants of River.
• Neoceratodus(Australian lungfish) is found only
in Burnett and Mary rivers of Queens-land in
Australia.
• Protopterus(African lungfish) lives in large lakes
and rivers of tropical Africa.
• Lepidosiren(South American lungfish) found in
river Amazon and paraguay basin in South
America (Jorgensen et al.,2022).
10. Morphology
• Early members:long, with a thick, lumpy scale, a lobe, and
a higher degree of cranial ossification.
• Visible evolutionary trends include reduced ossification, a
shorter head area and a shorter body.
• Teeth:
• Special, two large thick plates with the tip of their teeth
pointing forward
• Use it to smash the crustaceans of underwater animals
(Webb et al.,2021).
11. Respiratory System
• Highly specialized respiratory system
• Their lungs are connected to the larynx and
pharynx without a trachea.
• The lungs of lungfish are subdivided into
numerous smaller air sacs, maximizing the
surface area available for gas exchange.
• Most extant lungfish species have two lungs,
with the exception of the Australian lungfish,
which only has one.
• The lungs of lungfish are homologous to the
lungs of tetrapods (Zhang et al.,2023).
12. General affinities with fishes
• Spindle shaped,eel-like body
• Body covered with Cycloid scales
• Presence of paired fins
• Diphycercal caudual fins
• Persistent notochord
• Lateral line Sense organs
• Branchial respiration
• Skull with little ossification
Fig.Cycloid Scales
https://www.uploads
.2017://image.png
13. Differences
• Have many characters with
modern amphibians close to and
different from other fishes
• Mouth communicates with nasal
cavity
• American lungfish has double
lung, heart two chambered
• Lung fish are closest living
relatives of tetrapods than to
coelacanths (Graham et
al.,2022).
Fig.Lung fish relation
with tetrapods
https://encrypted-
tbn0.gstatic.com/images
14. Behavior of lung fishes
• Show parental as well as migratory
behavior
• Carnivorous in nature,Voracious
• African lungfish-guard their eggs and
young ones.
• Capable of surviving in both water and
mud
• During dry season- burrow in mud
• When conditions improve, resume their
aquatic lifestyle (Hossain,2021).
15. Unique Facts of Lung fish
Adaptations
• Breathing adaptations-posses both gills and
primitive lungs
• In summer when they are dry,often hide in the mud
for summer sleep until the rainy season comes.
• This helps the lungfish to escape the dry
environment and promote the ethnic reproduction
• Shows Estivation-including the excretion of a
mucus “cocoon” and digestion of the fish’s own
muscle tissue to obtain nutrients.
• African lungfish can aestivate for 4 years
(Zhang,2022)
16. Importance
• The economic importance of lungfish is slight
• Ecological importance-Apex predator
• Culture and culinary Importance-As a symbol of
fertility,strength and longevity
• As a traditional food source:South American lungfish
• Biomedical Research –Model organism
• Ecotourism and education
17. Recent Research findings
• Recently scientists have been studying about
• Formation of lungfish bone- found similar to
early human limbs
• Leave the body recently is a bone ,some small
branches at the top of bone
• These small branches extend outward-Fins are
formed
• That bone look alike human finger or toe
• Research on the neurophysiology of lungfish
provides insights into the neural mechanisms
underlying their unique behaviors and
physiological adaptations. (Amaral,2023).
18. Conservation status
• Lungfish face threats from:
• Habitat loss
• Pollution ,and
• Overexploitation
• Conservation efforts aimed at preserving
their natural habitats are essential for
Ensuring the long-term survival of
lungfish populations (Wang
&Zhang,2023).
19. References
• Amaral, D. B., & Schneider, I. (2023). Fins into
limbs: Recent insights from sarcopterygian fish.
Genesis, 56(1), e23052.
• Wang, Q., & Zhang, H. (2023). “Conservation
genetics of endangered lungfish populations.”
Conservation Genetics, 15(4), 330-345.
• Graham, J. B., Wegner, N. C., & Miller, L. A.
(2022), Breathing air in air: in what ways might
extant amphibious fishes teach us about early
tetrapods?. Integrative and Comparative Biology,
57(1), 25-38.
