Class SARCOPTERYGII


Common name: Lobe-finned fishes and the Tetrapods (four-legged vertebrates)
Summary:

The Sarcopterygii, the lobe-fin fishes comprise one of two living lineages of bony fishes. The other lineage is the Actinopterygii - the ray-finned fishes.

Although ray-finned fishes are the largest and most successful vertebrae lineage, one lobe-fin group was very successful and gave rise to the four-legged vertebrates - the tetrapods (including humans). One group (clade) of lobefin fishes, the Lungfishes (Dipnoi) has a fossil history dating back to the early Devonian, more than 400 million years ago. Lungfishes are the closest living sister taxon to the tetrapods.

Lobe-fins have fleshy pectoral and pelvic fins that are each joined to the body by a single bone. The pectoral fins articulate with the shoulder via the humerus (the same bone we have in our upper arm) and the pelvic fins articulate to the pelvis via the femur (our upper leg bone).

The lobe-fins first appeared in the fossil record during the Lower Devonian period, and became very successful. Today, however, there are only eight living lobe-fins: two species of coelocanth and six species of lungfish.

Author: Clement, A.M. & Bray, D.J. 2023

Cite this page as:
Lobe-fins, SARCOPTERYGII in Fishes of Australia, accessed 27 Feb 2024, https://fishesofaustralia.net.au/Home/class/7

References


Clement, A.M. & Ahlberg, P.E. 2014 The First Virtual Cranial Endocast of a Lungfish (Sarcopterygii: Dipnoi). PLoS ONE 9(11): e113898. https://doi.org/10.1371/journal.pone.0113898