Skip to main content

West African Lungfish

 Dear Fellow Readers,

This post talks about the African lungfish, specifically its classification within the Chordata phylum and its characteristics that demonstrate vestigiality.

African Lungfish/ Protopterus annectens
Phylum: Chordata

Order: Dipnoi

Family: Lepidosirenidae

Genus: Protopterus

Per the name, the African Lungfish is distributed throughout Africa. Being an obligate air breather they are seen in basins and rivers. As of today, there are only seven known species of lungfish, being found in Africa, South America, and Australia. Being abundant since the Triassic geologic period they are thought to be over 250 million years old (phylogenetically speaking).

While they do retain marginal teeth and an ossified braincase it has been significantly reduced in size due to vestigiality. This is also visible in something called the cosmine which has been lost in post-Devonian (between ~419-358 million years ago) lungfishes.

While called Lungfish they are actually able to live on land for months and sometimes even years on end.

Lungfishes are thought to be the closest living relatives to tetrapods. with a brain that demonstrates certain similarities with lissamphibians, internal nostrils, and the four similarly sized limbs like tetrapods it is easy to believe this as true. While there are other similarities 400 million years ago the evolution of limbs from fish fins happened allowing vertebrates to leave the water. This allowed tetrapods (amphibians, reptiles, birds, and mammals) to live on land.

Until next time,

Sol

Labels:

Comments

Post a Comment

Popular posts from this blog

Gymnosperms, Angiosperms, and the life cycle of all Plants

 Hello everyone, Today I decided to think about the difference between Gymnosperms and Angiosperms. While Gymnosperms do have four phylum and Angiosperms one, Phylum Anthophyta/ Flowering plants compose around 250,000 known species while Gymnosperms altogether equate to around 806 known species. The major difference between Gymnosperms and Angiosperms is that one has seeds not enclosed in chambers while the other has its seeds develop inside chambers (within flowers). With the numbers above and the inclusion of nonvascular and seedless plants, we can approximate that nearly 90% of living plant species are angiosperms. Now let's talk about the life cycle of all plants. Plants go through a process called alternation of generations between gametophytes and sporophytes. While this does not occur in charophytes (there is always an exception to the rule in biology) this type of reproductive cycle came from green algae. Basically, the process goes as such: The gametophyte produces haplo...
Post a Comment
Read more

Flatfish and Sharks

Dear Readers, This post will talk about whether several flatfish observed illustrate convergent evolution or homologous evolution. We will also discuss the difference between sharks and 'ordinary fish' and how they are easily distinguished from one another.  Flat Fish Those visible in the large monumental hall were The European Plaice/ Pleuronectes platessa and Sole/ Solea solea.  European Plaice and Solea Solea Both flatfish come from the same order being Pleuronectiformes. They are both found in similar habitats like the Mediterranean and enjoy burrowing themselves in the sandy or muddy seabed. Since they come from the same order we can hypothesize that both the Common Sole and European Plaice have a common ancestor.  Common Stingray with leopard shark directly above Unlike the two flatfish, Dasyatis pastinaca (Common Stingray) shares the same phylum with the flatfish, however not much else. Diverging into the class Chondrichthyes. Much like the flatfish they can be fou...
Post a Comment
Read more