Earth:Cratoraricrus

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Cratoraricrus is an extinct genus of centipedes in the family Scolopendridae containing the species Cratoraricrus oberlii. It was described by paleontologist Heather M. Wilson in 2003, becoming the fourth known Mesozoic centipede. The Nova Olinda Member of the Early Cretaceous Brazilian Crato Formation, where the remains were found, is known for its excellent preservation of terrestrial arthropods, including other centipede genera, which are otherwise rare in the fossil record. The type specimen is 54 millimeters (2.1 in) long, with parts of the head missing, making the presence or absence of eyes unclear. The paleoenvironment in which it was preserved may have been subject to hypersaline conditions. A variety of other arthropods have been discovered from the Crato Formation, along with fishes, pterosaurs, turtles, and various types of plants.

Discovery and naming

Extent of the Santana Group, to which the Crato Formation belongs, in blue

Cratoraricrus was described by paleontologist Heather M. Wilson in 2003. The type species was named Cratoraricrus oberlii, with the genus name in reference to the Early Cretaceous Brazilian Crato Formation, where the remains were found, and the Latin words rar (lit. thin) and crus (lit. leg). The specific epithet was in honor of its collector, Urs Oberli. Wilson remarked on the overall rareness of centipedes in the fossil record, but described the Nova Olinda Member (the part of the Crato Formation where Cratoraricrus was found) as a Konservat-Lagerstätte for terrestrial arthropods, where three out of the four known Mesozoic centipede taxa at the time had been found. She also stated that all known Mesozoic centipedes, including Cratoraricrus, are indistinguishable from modern centipedes.[1]

Description

The type specimen of Cratoraricrus oberlii was noted for its bisegmented tarsi (the furthest part of the leg from the body), paramedian (near the middle of the body) sternal grooves, and slim ultimate legs (an anatomical feature unique to centipedes). The preserved remains include the head and 21 leg-bearing segments. From the front of the head to the end of the last segment, it is 54 millimeters (2.1 in) long. Parts of the tergite (upper portions) of segments 18, 19, and 20 are missing. Parts of the head and the tergite of the forcipules (venom-injecting organs unique to centipedes) are also missing, revealing internal structures and the mouthparts under the head, although most of the head has been filled in by minerals, obstructing the rest of the internal and ventral portions. Parts of the mandibles and a few pieces of the right antenna are preserved, while the presence or absence of eyes is unclear.[1]

Each leg possesses six podomeres (segments), of which only three are preserved for the ultimate legs. One of the podomeres of the ultimate legs, known as the prefemur, was interpreted as having had numerous spines. All podomeres are long and slender, with a length approximately five times their width.[1]

Classification

Wilson placed Cratoraricrus in the family Scolopendridae within the order Scolopendromorpha.[1] In 2006, Cratoraricrus oberlii was reported to be one of only two scolopendrid centipede species known from the Mesozoic (along with Velocipede betimari) and the better understood of the two,[2] while as of December 2025, a catalog of fossil centipedes published in the journal Arthropoda lists an additional record of indeterminate scolopendrid remains from Burmese amber (though it also lists Velocipede as incertae sedis).[3] Researchers Jahnavi Joshi and K. Praveen Karanth of the Indian Institute of Science selected Cratoraricrus as one of three fossil centipedes used to calibrate their molecular clock estimates of the diversification of scolopendrid centipedes of South India.[4]

Paleoecology

Other arthropods collected from the Crato Formation; from top left, a whip scorpion, an orthopteran, an odonate, and three hemipterans

The paleoenvironment of the Crato Formation was originally interpreted as a saline lake, though some 2000s authors proposed a marine environment.[5] A 2017 study supported the earlier interpretation of a saline lake given the lack of marine fossils,[5] while a 2020 study argued that the site represents a freshwater environment given the presence of freshwater taxa, but that the area would have been subject to frequent hypersaline and alkaline conditions.[6] The Crato Formation is dated to the Aptian,[1][5][6] while the Nova Olinda Member has been suggested to be latest Aptian to early Albian in age.[1] Other arthropods include the centipedes Velocipede and Fulmenocursor; many winged insects; and rarely spiders, whip spiders, whip scorpions, scorpions, and a japygid (a member of the order Diplura of non-insect hexapods). Some of the best-preserved non-arthropod remains include fishes, pterosaurs, and turtles.[6] Plants include angiosperms, ferns, and gymnosperms, and there is evidence of a wide range of interactions between plants and insects, including insect galls, feeding along the leaf margin, leaf mining, oviposition, and skeletonization (stripping away of most of the leaf).[7] Stromatolites as high as 100 centimeters (3.3 ft) have been found in one Nova Olinda quarry.[5]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Wilson, Heather M. (2003). "A New Scolopendromorph Centipede (Myriapoda: Chilopoda) from the Lower Cretaceous (Aptian) of Brazil". Journal of Paleontology 77 (1): 73–77. ISSN 0022-3360. https://www.jstor.org/stable/4094718. Retrieved 22 January 2026. 
  2. ↑ Edgecombe, Gregory D.; Giribet, Gonzalo (1 January 2007). "Evolutionary Biology of Centipedes (Myriapoda: Chilopoda)". Annual Review of Entomology 52 (1): 151–170. doi:10.1146/annurev.ento.52.110405.091326. 
  3. ↑ Cadenas-Amaya, Suzzet; Riquelme, Francisco; Hernández-Patricio, Miguel; Cupul-Magaña, Fabio (26 December 2025). "The Global Fossil Record of Chilopoda". Arthropoda 4 (1): 1. doi:10.3390/arthropoda4010001. 
  4. ↑ Joshi, Jahnavi; Karanth, K. Praveen (September 2011). "Cretaceous–Tertiary diversification among select Scolopendrid centipedes of South India". Molecular Phylogenetics and Evolution 60 (3): 287–294. doi:10.1016/j.ympev.2011.04.024. 
  5. ↑ 5.0 5.1 5.2 5.3 Warren, Lucas Veríssimo; Varejão, Filipe Giovanini; Quaglio, Fernanda; Simões, Marcello Guimarães; Fürsich, Franz Theodor; Poiré, Daniel Gustavo; Catto, Bruno; Assine, Mario Luis (January 2017). "Stromatolites from the Aptian Crato Formation, a hypersaline lake system in the Araripe Basin, northeastern Brazil". Facies 63 (1). doi:10.1007/s10347-016-0484-6. 
  6. ↑ 6.0 6.1 6.2 Varejão, Filipe Giovanini; Silva, Victor Ribeiro; Assine, Mario Luis; Warren, Lucas Veríssimo; Matos, Suzana Aparecida; Rodrigues, Mariza Gomes; Fürsich, Franz Theodor; Simões, Marcello Guimarães (2021). "Marine or freshwater? Accessing the paleoenvironmental parameters of the Caldas Bed, a key marker bed in the Crato Formation (Araripe Basin, NE Brazil)". Brazilian Journal of Geology 51 (1). doi:10.1590/2317-4889202120200009. 
  7. ↑ Filho, Edilson Bezerra dos Santos; Adami-Rodrigues, Karen; Lima, Flaviana Jorge de; Bantim, Renan Alfredo Machado; Wappler, Torsten; Saraiva, Antônio Álamo Feitosa (9 August 2019). "Evidence of plant–insect interaction in the Early Cretaceous Flora from the Crato Formation, Araripe Basin, Northeast Brazil". Historical Biology 31 (7): 926–937. doi:10.1080/08912963.2017.1408611. 

Wikidata ☰ Q137948234 entry



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