#rebellatrix

Polar Rebellatrix - Veiled Sea

Endless Ocean Luminous, Nintendo Switch

Cambrian baby

Devonian baby

Triassic baby

By Tas Dixon

Etymology: Rebel

First Described By: Wendruff and WIlson, 2012

Classification: Biota, Archaea, Proteoarchaeota, Asgardarchaeota, Eukaryota, Neokaryota, Scotokaryota, Opimoda, Podiata, Amorphea, Obazoa, Opisthokonta, Holozoa, Filozoa, Choanozoa, Animalia, Eumetazoa, Parahoxozoa, Bilateria, Nephrozoa, Deuterostomia, Chordata, Olfactores, Vertebrata, Craniata, Gnathostomata, Eugnathostomata, Osteichthyes, Sarcopterygii, Actinistia, Coelacanthiformes, Rebellatricidae

Status: Extinct 

Time and Place: 252 to 247 million years ago, from the Induan to the Olenekian of the Early Triassic.

Rebellatrix is only known from British Columbia.

Physical Description: Rebellatrix is a coelacanth like no other. Its body is a more elongate and slender than other coelacanths, and each fin (which, being a sarcopterygian, has a fleshy “limb” for the base) has a reduced rays. But its most distinctive feature is its tail. In living coelacanths, the caudal fin forms a broad, continuous shape. It is formed from three lobes: a large upper and lower lobe, and one tiny one in the middle at the tip of the tail. In Rebellatrix, however, the upper and lower lobes have greatly expanded, projecting far posteriorly and forming pointed shapes. This gives the tail a half-moon shape, similar to tuna or some sharks. The body was covered with ridged scales and bore a complex lateral line system. The head shape is unknown, but here we’ve restored it as pikelike based on its inferred ecology.

Diet: Rebellatrix was likely an active predator; its diet likely consisted of smaller fish.

Behavior: Rebellatrix was unique among coelacanths in being a fast-moving pursuit predator; the shape of the tail fin is similar to those of fast oceanic predators today. Also uniquely, the elements of the tail fin have fused. This would have led to a less flexible tail than modern coelacanths, who are lazier “lurk-and-lunge” predators that use every fin except the tail fin for most movement. Rebellatrix, by contrast, used its tail as the basis of sustained, rapid movement, and used the other fins to fine-tune its swimming.

Ecosystem: Rebellatrix was found in the Sulphur Mountain Formation of Canada. At the time, the area was a continental shelf. Based on how rare Rebellatrix is, it is likely that it lived in the open sea and only occasionally visited the area. In fact, few other species are known from the same localities, but these include the coelacanthimorph Belemnocerca and the ichthyosaur Utatsusaurus.

Other: Rebellatrix shows that, contrary to popular belief, coelacanths were not evolutionarily stagnant for over 300 million years - there was some evolutionary innovations along the line. And, along with Saurichthys, Rebellatrix represents other fish filling the “active pursuit predator” niche that was dominated by sharks before the Permian-Triassic Extinction.

~ By Henry Thomas

Source (there’s only one so no cut)

Coelacanths are famous for being “living fossils”, completely disappearing from the fossil record at the end of the Cretaceous but then being rediscovered alive just 80 years ago. But although they’re often thought to have physically changed very little over the last 300 million years or so, more recent discoveries are starting to show that coelacanth body forms and lifestyles were actually more varied in the distant past.

Meet the wonderfully-named Rebellatrix divaricerca, from the Early Triassic of British Columbia, Canada (~251-247 mya). Measuring around 1.3m long (4′3″), its body shape and large symmetrical forked tail suggest it was adapted for fast swimming. Unlike its slow-moving deep-water modern relatives this coelacanth was a speedy oceanic active predator, convergently similar to tuna or some sharks.

Scintillating Dive - Veiled Sea

Endless Ocean Luminous, Nintendo Switch

Rebellatrix - Veiled Sea

Endless Ocean Luminous, Nintendo Switch

Triopticus 

By @cry-olophosaurus​ 

Versus 

By @i-draws-dinosaurs​

Rebellatrix

Click on the above links to refresh your memory about these animals! And feel free to use this post to debate and argue on what people should vote for!