Camptostroma

Not to be confused with Camptostoma.

Camptostroma roddyi is an extinct echinoderm from the Bonnia-Olenellus Zone of the Early Cambrian Kinzers Formation near York and Lancaster, Southeastern Pennsylvania. It is the only known species in the genus Camptostroma, as other species referred to this genus "do not appear to be cogeneric."

Camptostroma Temporal range: Early Cambrian
Artist's reconstruction
Scientific classification
Kingdom:	Animalia
Phylum:	Echinodermata
Class:	†Edrioasteroidea
Genus:	†Camptostroma
Species:	†C. roddyi
Binomial name
Camptostroma roddyi Ruedemann 1933

Anatomy

In life, Camptostroma would have resembled a cupcake, with the mouth in the center of the upper surface, with ambulacra radiating from it in the 2-1-2 pattern common in early echinoderms. The ambulacra are straight in juveniles, but in larger adult specimens, ambulacra A, B, C, and E curve clockwise while ambulacrum D curves counter-clockwise. The anus is near the periphery between ambulacra C and D.

The ambulacra may have extended beyond the upper surface on stubby arms. While this diagnosis is tentative, ongoing work appears to support it.

Classification and relationships

Camptostroma roddyi fossil on display at the Smithsonian's National Museum of Natural History.

While initially considered to be a scyphozoan due to the fossil's medusoid shape, later investigation detected the presence of stereom plates with the calcitic cleavage pattern diagnostic of echinoderms.

The Treatise on Invertebrate Paleontology accepted Durham's 1966 assigment of Camptostroma to its own class, Camptostromatoidea. However, a later revision of the Treatise's classification omitted this class.

Camptostroma has since been placed in a class of basal echinoderms, the Edrioasteroids, although some recent authors only describe it as "edrioasteroid-like".

Recent research has found weak support for the recovery of Camptostroma as the sister group of the crinoids. However, other phylogenies are ambiguous regarding whether it is closer to the crinoids, eocrinoids, or eleutherozoans.

References

Works cited

• Durham, J. W. (1 September 1966). "Camptostroma, an Early Cambrian Supposed Scyphozoan, Referable to Echinodermata". Journal of Paleontology. 40 (5): 1009–1255. ISSN 0022-3360. JSTOR 1301996.
• Durham, J. Wyatt (1967). "Addendum: Camptostromatoids". In Moore, Raymond C. (ed.). Treatise on Invertebrate Paleontology, Part S: Echinodermata 1. Vol. 1. University of Kansas Press. pp. S627–S631. Retrieved 29 October 2024.
• Guensburg, Thomas E.; Mooi, Rich; Mongiardino Koch, Nicolás (2023). "Crinoid calyx origin from stem radial echinoderms". Journal of Paleontology. 97 (5): 1092–1115. doi:10.1017/jpa.2023.14.
• Guensburg, Thomas E.; Sprinkle, James; Mooi, Rich; Lefebvre, Bertrand; David, Bruno; Roux, Michael; Derstler, Kraig (2020). "Athenacrinus n. gen. and other early echinoderm taxa inform crinoid origin and arm evolution". Journal of Paleontology. 94 (2): 311–333. doi:10.1017/jpa.2019.87.
• Paul, C. R. C.; Smith, A. B. (November 1984). "The early radiation and phylogeny of echinoderms". Biological Reviews. 59 (4): 443–481. doi:10.1111/j.1469-185X.1984.tb00411.x.
• Rahman, Imran A.; Zamora, Samuel (July 2024). "Origin and early evolution of echinoderms". Annual Review of Earth and Planetary Sciences. 52: 295–320. doi:10.1146/annurev-earth-031621-113343. hdl:10141/623070.
• Sprinkle, J. (1980). "An Overview of the Fossil Record". Notes for a Short Course: Studies in Geology. 3: 15–26. doi:10.1017/S0271164800000063.
• Zamora, Samuel; Deline, Bradley; Álvaro, J. Javier; 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.