Mode of life of the macrofossils from the cabeças formation (Devonian), Parnaíba Basin, Brazil

SESSIONS OF THE ACADEMIA BRASILEIRA DE CIÊNCIAS

SUMMARY OF COMMUNICATIONS

PALEONTOLOGICAL TOPICS

ALEXANDER W. A. KELLNER (ORGANIZER)

MODE OF LIFE OF THE MACROFOSSILS FROM THE CABEÇAS FORMATION (DEVONIAN), PARNAÍBA BASIN, BRAZIL

CLEBER F. DA SILVA ¹AND DEUSANA M.C. MACHADO ²

¹Estagiário do Laboratório de Comunidades Paleozóicas, Departamento de Ciências Naturais, ECB, CCBS, UNI-RIO, Av. Pasteur 428, Urca, Rio de Janeiro - RJ.

²Laboratório de Comunidades Paleozóicas, Departamento de Ciências Naturais, ECB, CCBS, UNI-RIO, Av. Pasteur 428, Urca, Rio de Janeiro - RJ.

Presented by DIOGENES DE ALMEIDA CAMPOS

The Cabeças Formation belongs to the Canindé Group and corresponds to the Devonian depositional sequence of the Parnaíba Basin. This unit is divided in two members, from base to top: Passagem and Oeiras. The Passagem Member is of marine-deltaic origin and yielded the macrofossils studied here; the Oeiras Member is afossiliferous and was deposited under fluvio-deltaic conditions. Fifteen taxa of the twenty-five known from the Passagem Member were found in the studied samples, as follows: six brachiopods, six bivalves, one trilobite and one tentaculitid. Besides those, five additional ones are reported for the first time in this unit: two brachiopods (lingulid and Terebratulidae indet.), one inderminated bivalve and two crinoids [Hexacrinites (?) sp. and Pentagonostipes (?) sp.]. These species fell under seven modes of life: (1) reclined epibenthic suspension feeders, represented by Pleurochonetes comstocki (Rathbun 1874) and Mucrospirifer (?) pedroanus (Rathbun 1874); (2) attached epibenthic suspension feeders, represented by Pustulatia(?) curupira (Rathbun 1874), Mutationellinae indet. D, Rhipidothyrididae sive Mutationellidae indet. B, Rhipidothyrididae sive Mutationellidae indet. D, Terebratulidae indet., Hexacrinites (?) sp. and Pentagonostipes (?) sp.; (3) infaunal suspension feeders, represented by Grammysioidea lundi (Clarke 1899), Grammysioidea sp. A and Tentaculites sp. (cf. T. eldregianus Rathbun 1874); (4) semi-infaunal suspension feeders, represented by Spathella pimentana (Rathbun 1874); (5) infaunal deposit feeders, represented by Cucullella triquetra (Conrad 1841), Nuculites (Nuculites) aff. N. (N) oblongatus (Conrad 1841) and Palaeoneilo sp. A; (6) mobile epibenthic predator, represented by Metacryphaeus meloi (Carvalho et al. 1997); and (7) mobile epibenthic herbivore, represented by Plectonotus derbyi (Clarke 1899). These habits and their abundance agree with the previous suggestion that the Cabeças Formation was deposited in a shallow marine environment near the coast with moderated disturbance from marine currents. — ( December 20, 2001 ).

Publication Dates

• Publication in this collection
  17 July 2002
• Date of issue
  June 2002