Biology:Lichenoides

Lichenoides is an extinct genus of eocrinoid echinoderms that lived during the Middle Cambrian. It is endemic to West Gondwana, and has been found in what is now Bohemia and Spain.

Description

Lichenoides is an eocrinoid with an ovoid to nearly circular theca. In place of the more typical stem, the aboral surface ends with a varying number of small platelets. Brachioles are singular or split into a pair just above the base.

Ecology

L. priscus, the type species, occurs in deeper water, lower energy sediments, while L. vadosus is found in shallower water, higher eneregy sediments. The genus has been interpreted as a soft sediment sticker in the past, but more recent work with additional specimens has led to it being re-interpreted as a hard substrate attacher.

Phylogeny

Lichenoides the type genus of the family Lichenoididae (sometimes misspelled Lichenoidae). Lichenoididae is crownward from the Lyracystidae and Eocrinidae within the order Gogiida but basal to all other eocrinoids and other blastozoans that are more derived than gogiids as shown in the following cladogram, after Nardin et al. 2017 with slight modifications:

Blastozoa	Lepidocystidae   Kinzercystis     Vyscystis     Lepidocystis       Felbabkacystidae Felbabkacystis       Lyracystis         Akadocrinus     Gogia     Sinoeocrinus     Ubaghsicystis         Lichenoides       Trachelocrinus     Ridersia     (derived Blastozoa)

References

Works cited

• Nardin, Elise; Lefebvre, Bertrand; Fatka, Oldřich; Nohejlová, Martina; Kašička, Libor; Šinágl, Miroslav; Szabad, Michal (2017). "Evolutionary implications of a new transitional blastozoan echinoderm from the middle Cambrian of the Czech Republic". Journal of Paleontology 91 (4): 672–684. doi:10.1017/jpa.2016.157. Bibcode: 2017JPal...91..672N. (Note: This source misspells "Lichenoididae" as "Lichenoidae" and "Lepidocystidae" as "Lepidocystoidae", both contrary to the Treatise on Invertebrate Paleontology, Part S, Echinodermata 1, and includes Lyracystis in Eocrinidae while both PBDB and IRMNG place it in its own family together with Eocrinidae in Gogiida; as this paper does not formally reassign Lyracystis, the more broadly accepted Gogiida interpretation is shown here.)
• Parsley, Ronald L.; Prokop, Rudolf J. (2004). "Functional morphology and paleoecology of some sessile Middle Cambrian echinoderms from the Barrandian region of Bohemia". Bulletin of Geosciences 79 (3): 147–156. http://www.geology.cz/bulletin/fulltext/AParsley.pdf. 
• Smith, Andrew B.; Zamora, Samuel; Javier Álvaro, J. (2013). "The oldest echinoderm faunas from Gondwana show that echinoderm body plan diversification was rapid". Nature Communications 4. doi:10.1038/ncomms2391. 
• Zamora, Samuel; Deline, Bradley; Javier Álvaro, J.; Rahman, Imran A. (2017). "The Cambrian Substrate Revolution and the early evolution of attachment in suspension-feeding echinoderms". Earth-Science Reviews 171: 478–491. doi:10.1016/j.earscirev.2017.06.018. 
• Zamora, Samuel; Lefebvre, Bertrand; Javier Álvaro, J.; Clausen, Sébastien; Elicki, Olaf; Fatka, Oldrich; Jell, Peter; Kouchinsky, Artem et al. (2013). "Cambrian echinoderm diversity and palaeobiogeography". Early Palaeozoic Biogeography and Palaeogeography. Geological Society, London, Memoirs. 38. pp. 157–171. doi:10.1144/M38.13. 

Wikidata ☰ Q6543238 entry