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Share to Facebook Share to Twitter Share to Linkedin ‘Lungfish’ would have been a common sight in the Devonian period, about 400 million years ago. ..
. [+] Remarkably, six species of this ancient ichthyo-class have survived to present-day. Here they are.
getty The Devonian period of prehistory, spanning from about 420-360 million years ago, is sometimes referred to as the “Age of Fishes” due to the explosion of fish species that evolved during this time. After diverging from sharks and rays , fish from this period, and those that followed, evolved into two distinct classes: ray-finned fish and lobe-finned fish. Ray-finned fish are the ancestors of what we would normally think of as a fish today–defined by folding “accordion-like” fins that provide superior thrust-to-weight ratios for movement.
Swordfish, perch, puffers, seahorses, flounder, walleye, carp and salmon all fall into the ray-finned fish category. The other class of fish, referred to by scientists as lobe-finned fish, were much more common in prehistory than they are today. At present, only two species groups survive: coelacanths and lungfish.
However, they are just as fascinating as the fish we typically envision. The ancient coelacanth , for instance, was presumed extinct for sixty million years until it was miraculously rediscovered off the coast of South Africa in the 1930s. Lobe-finned fish have paired pectoral and pelvic fins that are fleshy and supported by a central bone structure, resembling limbs more closely than the fin rays of ray-finned fish.
This unique fin structure suggests a closer evolutionary relationship to the ancestors of terrestrial vertebrates, which is supported by other lines of evidence as well. Lobe-finned fish may well have been among the first vertebrate animals to make the transition from sea to land. What adds credibility to this theory is the fact that lungfish, the other surviving species group of lobe-finned fish, possess both lungs and gills, allowing them to breathe underneath and above water.
Here are the six extant species of lungfish, along with some of the characteristics that make them so unique and, possibly, the direct ancestors of all land-living vertebrates, from frogs, turtles and hawks to lions, chimpanzees and even humans. 1. Queensland Lungfish The Queensland lungfish is the only species of lungfish native to Australia.
getty MORE FOR YOU Google Chrome Deadline—You Have 72 Hours To Update Your Browser U.S. May Get Northern Lights On Monday Night As ‘Strong’ Aurora Predicted Samsung Updates Millions Of Galaxy Phones To Stop Users Leaving The Queensland lungfish, native to the freshwater rivers and lakes of Queensland, Australia, is one of the most primitive living fish species.
It has a robust, cylindrical body that can reach lengths of up to four feet. Its appearance is somewhat prehistoric, with a broad, flattened head and large, paddle-like pectoral and pelvic fins that give it a somewhat awkward but distinctive swimming style. While they have gills and can breath underwater, the Queensland lungfish also has a single lung that enables it to breathe air, which is vital for survival in oxygen-poor waters.
This lungfish’s unique and relatively unchanged morphology over millions of years offer valuable insights into early vertebrate evolution. Its adaptation to both gill and lung respiration allows it to thrive in various aquatic environments. The Queensland lungfish is also known for its long lifespan and slow growth.
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render(randId); }); })(); 2. South American Lungfish The South American lungfish is the only species of lungfish native to South America. getty The South American lungfish can be found primarily in the swampy, slow-moving rivers and wetlands of the Amazon Basin.
It has an elongated, eel-like body that can grow to about the same size as its relative, the Queensland lungfish. This species has a distinctive appearance with smooth, scaleless skin and long, filamentous pectoral and pelvic fins that resemble limbs more than typical fins. Its ability to breathe air is facilitated by two well-developed lungs, allowing it to survive in oxygen-depleted waters.
Unlike the Queensland lungfish, which is a facultative air-breather, the South American lungfish must breathe air to survive. During dry seasons, the South American lungfish can enter a state of estivation , where it buries itself in the mud and secretes a mucus cocoon to retain moisture. This adaptation enables it to survive prolonged periods of drought.
3. Marbled Lungfish The marbled lungfish is one of four lungfish species native to Africa. getty The marbled lungfish is native to the freshwater systems of East and Central Africa.
It is characterized by its distinctive marbled patterning, which varies from individual to individual, providing effective camouflage in its natural habitat. This lungfish has an elongated, slender body that can reach up to six feet in length. Its long, filamentous fins and smooth skin are adapted for navigating through dense aquatic vegetation and muddy substrates.
Marbled lungfish have two well-developed lungs for air-breathing, which is crucial during the dry season when water levels drop and oxygen levels decrease. They are also capable of entering a state of estivation, where they form a protective cocoon in the mud to survive until conditions improve. This survival strategy showcases their ability to endure extreme environmental fluctuations and is one of the many reasons lungfish have persisted for millions of years.
4. Gilled Lungfish The gilled lungfish is the smallest species of extant lungfish. opencage.
info, CC BY-SA 2.5 , via Wikimedia Commons The gilled lungfish is found in East Africa and is distinguished by its relatively small size compared to other lungfish species, growing up to around two feet in length. It features an elongated body with long, filamentous fins and smooth skin, adapted for navigating through its aquatic environment.
An example of a lungfish in estivation, nestled in a burrow beneath a dried-up water source. getty Like other lungfish, during periods of drought, the Gilled lungfish can enter estivation by encasing itself in a mucous cocoon within the mud. This adaptation allows it to conserve moisture and energy until the water levels rise again.
5. West African Lungfish The West African lungfish can remain in estivation for up to a year. By Gőtehal.
jpg: Mathaederivative work: Bff - Gőtehal.jpg, CC BY 2.5, https://commons.
wikimedia.org/w/index.php?curid=10700741 The West African lungfish is distributed across freshwater habitats throughout sub-Saharan Africa, including rivers and floodplains.
It grows to around three feet in length. This species has a robust, elongated body with long, filamentous fins that are adapted for navigating through its often turbid and slow-moving aquatic environment. The West African lungfish also exhibits a distinctive mottled coloration that aids in camouflage.
Like other lungfish, the West African lungfish possesses both gills and a pari lungs (except the Queensland lungfish, which has a single lung), enabling it to thrive in low-oxygen environments. 6. Spotted Lungfish Illustration of a spotted lungfish attacking a frog.
De Agostini via Getty Images The spotted lungfish is native to the freshwater systems of Central Africa, such as the Congo River basin. It is characterized by a striking pattern of spots or speckles on its body, which helps it blend into the muddy and vegetated environments where it resides. This lungfish typically reaches lengths of up to four feet and has a slender, elongated body with long fins that facilitate movement through dense aquatic vegetation.
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