C. perplexa by Oksana Vernygora
Callichimaera is a species of small aquatic crustecean known from the middle Cretaceous Colombia and United States.[1] The type and only species of the genus of C. perplexa. Because it possesses a unique combination of anatomical features, it is interpreted to be the "platypus of crabs".[2]
The presence of certain features in this species, such as its large claws and swimming limbs, confirm that those the features were present in the crab lineage up to 95 million years ago.[3][4] It evolved during the Cretaceous, the whole evolution and immense diversification during the cretaceous has a whole genera of names, such as the Cretaceous Crab Revolution.[5]
Etymology[]
Paleoart - Reconstruction
The generic name Callichimaera is derived from the Ancient Greek word: (calli) meaning beautiful, and (chimaera) meaning a composite mythological animal, a reference to the bizarre forms and characteristics of this species. The specific name is derived from the Latin word (perplexus) meaning perplexing, directly referencing to the complex anatomical affinities this species display.[6]
Description[]
Callichimaera possesses features that are commonly associated with the larval crab stage called the megalopa. This includes features like large compound eyes, a small fusiform body, and thin mouth parts. However, the fossil crabs also show evidence of sexual maturity, suggesting they are adult forms.[7] This species likely evolved those larval features via a process called heterochrony. These crabs were small, with many that are nearly the size of a U.S. quarter. The crabs range in size from a few millimeters up to two centimeters, also suggesting that both juveniles and adults are present, probably indicating group/social behavior.[8]
Callichimaera-perplexa reconstruction (A and B Line drawing of dorsal)
Dorsal frontal and ocular features Callichimaera perplexa (Fossil)
Callichimaera has large paddle-like legs, it was probably an active swimmer, opposed to several crab species that predominantly living on the seafloor. The Callichimaera does not have the typical crab-like shape, something that has occurred several times among crabs since the Cretaceous. Because Callichimaera has large paddle-like legs, it was probably an active swimmer, opposed to predominantly living on the seafloor.[9]
Paleoecology[]
Callichimaera lived in a tropical environment. The fossils are rarely preserved in tropical settings in comparison to other parts of the world, making this fossil an even more unusual discovery! The Callichimaera was discovered in deposits also containing comma shrimp and caridean shrimp.[10][11][12][13][14]
Other Wiki[]
https://prehistoric-wiki.fandom.com/wiki/Callichimaera
References[]
- ↑ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6482010/
- ↑ https://news.yale.edu/2019/04/24/meet-callichimaera-perplexa-platypus-crabs
- ↑ https://www.nationalgeographic.com/science/article/how-did-crabs-evolve-crabbiness-complicated
- ↑ https://www.bbc.co.uk/newsround/48077649
- ↑ https://www.researchgate.net/figure/Dorsal-frontal-and-ocular-features-in-Callichimaera-perplexa-n-gen-n-sp-from-the_fig2_332670286
- ↑ https://www.washingtonpost.com/science/2019/04/25/behold-beautiful-nightmare-crab-that-had-wrench-like-claws-enormous-cartoonish-eyes/?noredirect=on
- ↑ https://www.theglobeandmail.com/canada/article-enigmatic-swimming-crab-fossil-offers-lessons-on-evolutions/
- ↑ http://www.sci-news.com/paleontology/callichimaera-perplexa-07128.html
- ↑ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6501934/
- ↑ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6939266/
- ↑ https://phys.org/news/2019-04-callichimaera-perplexa-platypus-crabs.html
- ↑ https://www.eurekalert.org/pub_releases/2019-04/yu-mcp042219.php
- ↑ https://www.newsweek.com/callichimaera-perplexa-platypus-crab-world-95-million-years-1404530
- ↑ https://www.zmescience.com/science/fossil-friday-crab-callichimaera-888453534/