The Coelacanth: A Living Fossil

Coelacanths: An Enigmatic Species

Coelacanths are curious kind of fish that is represented by two species of fish comprising the Indonesian coelacanth (Latimeria menadoensis), and African coelacanth (Latimeria chalumnae). The type of fish live around deep-water of African and Indonesian caves off the coasts and are characterized as lobe-fined fish. They are approximately two meters in length and do not resemble any living fish on earth. Furthermore, the fish has a unique bicaudal tail and hinge on the top of its skull which facilitates to expand its gape. They also have fleshy limb-like fins and skeletal supporting structures. Understanding the body features and nervous system is an integral part in biology that has contributed to the understanding of the complex human body functions. Upon discovering coelacanth, the researchers analyzed the gene sequencing of the fish to build an evolutionary tree of terrestrial and marine animals including the human body (Robinson & Amemiya, 2014).

Unique Features of the Coelacanth

The coelacanth has been attributed to unique features among the living fish. For instance, the presence of a rostral organ in the snout which is part of the electrosensory structure and an intracranial hinge or joint found in the skull which facilitates the front portion of the cranium to swing upwards thus enlarging the gape of the mouth (Robinson & Amemiya, 2014). The unique feature does not exist in other living vertebrates. Anatomical feature including fluid-filled notochord is also a unique and primitive feature in vertebrate. The unique feature underlies the spinal cord thus extending the length of the body demonstrating vertebrates that are fully developed or does not have bony centra (Larhammar & Bergqvist, 2013).

The Coelacanth’s Role in Human Evolution

The scientists articulate that an ancestor of lungfish about 420 million years ago played an integral role in generating the link between the two types of animals which, therefore, provides insights in understanding the complexity of human evolution and development. The African Coelacanth is considered the closest living fish that is related to tetrapod. Consequently, the genomic information on the type of fish is significant in studying land adaptations during the evolution and development of vertebrates including human beings. The African Coelacanth is well-known for its morphological similarity to its fossil ancestors thus being referred to as the living fossil as it has not shown substantial evolution over a long time (Larhammar & Bergqvist, 2013). In particular, the fish’s retrogenes can serve as a critical investigation and implications for scientists to gain novel insights into the evolution and development of Coelacanths and thus water-to-land vertebrates adaptations (Du & He, 2015).

Coelacanth’s Contributions to Understanding the Human Genome

Furthermore, analyzing and scientific studies of Coelacanth’s early diverging lineage mainly, the retention of its receptors from its ancestral jawed vertebrate has provided sufficient knowledge for researchers to discover that human genome has lost three of its seven receptors during its evolution and development. The receptors demonstrate the typical characteristics of vertebrates (Du & He, 2015). Moreover, studies of the Coelacanths indicate that the species had a local duplicate of PYY genes known as a pancreatic polypeptide that was formerly identified in tetrapod. Consequently, the duplication occurred in early during the sarcopterygian lineage. Therefore, findings ascertaining the ancient complexity of the human body and how it functions showing that mammals have lost more NPY receptor as compared to another vertebrate lineage. However, the Coelacanth has all three peptides that are found in tetrapod has retained the innate receptors that have shown no losses or gains (Berquist, Galinsky, Kajiura, & Frank, 2015).

Coelacanth: The Missing Link and Beyond

In conclusion, it is evident that coelacanth is the missing link to the tetrapod yet its evolutionary relationship has been controversial over the years. There have been numerous confounding ideologies spawning from unusual features displayed by coelacanths. However, it is apparent that having comprehensive insights regarding the evolution and development of coelacanths is critical in understanding the evolution and functioning of the complex human body and other vertebrates. Therefore, scientists use this information in understanding the water-to-land adaptations of mammals by using discoveries of Coelacanth researches.

References

Berquist, R., Galinsky, V., Kajiura, S., & Frank, L. (2015, March 11). The Coelacanth Rostral Organ is a Unique Low-Resolution Electro-dectetor that facilitates the Feeding Strike. Scientific Reports, 5(8962). doi:10.1038/srep08962

Du, K., & He, S. (2015, November 10). Evolutionary Fate and Implications of Retrocopies. BMC Genomics. doi:10.1186/s12864-015-2178-9

Larhammar, D., & Bergqvist, C. (2013, March 8). Ancient Grandeur of the Vertebrate Neuropeptide Y System Shown by the Coelacanth Latimeria Chalumnae. Frontier in Neuroscience , 7(27). doi:10.3389/fnins.2013.00027]

Robinson , M., & Amemiya, C. (2014, January). Coelacanths. Current Biology, 24(2), 62-63. doi:10.1016/ELSEVIER_CM_POLICY