Paper Number: 4128
Taxonomic remarks and stratigraphic implications of Cloudina species in Neoproterozoic strata
Adôrno, R. R1,2; Carmo, D. A.1; Denezine, M.1; Walde, D. H. G.1;Guimarães, E. M. 1; Vieira, L.C. 1; Boggiani, P.C. 3; Rodriguez, C.G. 1
1 Instituto de Geociências–Universidade de Brasília-UnB, rodrigo.adorno@cprm.gov.br
2CPRM/SGB–Serviço Geológico do Brasil.
3Instituto de Geociências. Universidade de São Paulo.
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The Tamengo Formation is mainly composed of dark, organic rich limestones and marls with occasional Cloudina [1; 2; 7;]. The Cloudina genus is represented by seven species restricted to the uppermost Ediacaran strata: 1. Cloudina lucianoi (Beurlen & Sommer, 1957) (Tamengo Formation, Brazil), 2. Cloudina hartmannae Germs, 1972 (Nama Group, Namibia), 3. Cloudina riemkae Germs, 1972 (Nama Group, Namibia), 4. Cloudina waldei Hann & Pflug, 1985 (Tamengo Formation, Brazil), 5. Cloudina lijiagouensis Zhang, Li & Dong, 1992 (Denging Formation, China), 6. Cloudina sinensis Zhang, Li & Dong, 1992 (Denging Formation, China), 7. Cloudina carinata Cortijo et al., 2010 (Membrillar olistostrome, Spain). Herein is presented an update concept about two species of Cloudina, their occurrences and respective stratigrhaphic distribution discussing a possible synonymy: C. hartmannae and the C. lucianoi. The occurrences of Cloudina lucianoi in the Tamengo Formation and Cloudina hartmannae in the Nama Group are discussed herein under evolutive aspect, in order to clarify the taxonomic concept and discuss a correlation between Ediacaran strata.
Despite the existence of the seven valid species of Cloudina, most publications are addressing occurrences of this genus does not reach the specific classification, restricting only the designation Cloudina sp. or just Cloudina. In the Tamengo Formation the Cloudina occurrences have been attributed to Cloudina lucianoi (Beurlen & Sommer, 1957) and Cloudina waldei Hann & Pflug, 1985. This second species, Cloudina waldei is lacking cone-in-cone structure so, it deserves to be replaced for other genus. Cloudina hartmannae is herein considered to be junior synonyms of Cloudina lucianoi. They share with the valid species, size, shape, outline and, additionally, stratigraphic distribution restricted to the upper Edicaran. Size and position of superposition of the cone-in-cone exoskeleton structure differs Cloudina lucianoi of Cloudina riemkae and Cloudina carinata. In these two last species, the superposition of cone-in-cone structure is restricted to the upper portion of each nested cone. On considering comparison with the two species from China, Cloudina lijiagouensis and Cloudina sinensis, both species are under revision by colleagues from China.
The detailed review of Cloudina hartmannae in progress shows that this species is a junior synonym of Cloudina lucianoi. This new concept leads to admit that Cloudina lucianoi was a cosmopolitan species, with occurrences confirmed in Namibia, South Africa, USA, Mexico, Brazil, Paraguay, Siberia and China and possible in Uruguay, Oman, Canada and Spain.
References:
[1] Almeida, F.F.M.de (1965). Boletim da Divisão de Geologia e Mineralogia-DNPM 117:1-11.
[2] Beurlen, K, and Sommer, F.W., (1957). Boletim DNPM, 168:1-35.
[3] Boggiani, P.C., et al., (1998) Rev. IG São Paulo 19(1/2):31/41.
[4] Cortijo, I., et al., (2010) Precambrian Research, 176:1-10.
[5] Germs, G.J.B. (1972) American Journal of Science, 272:752-761.
[6] Warren et al., (2014) Geology, 42(5):391–394.
[7] Zaine, M., (1991). Ph.D. Thesis, Universidade de São Paulo, Brazil.