Anais da Academia Brasileira de Ciências (2002) 74(2): 361–370 (Annals of the Brazilian Academy of Sciences) ISSN 0001-3765 www.scielo.br/aabc SESSIONS OF THE ACADEMIA BRASILEIRA DE CIÊNCIAS SUMMARY OF COMMUNICATIONS PALEONTOLOGICAL TOPICS (2) attached epibenthic suspension feeders, represented by Alexander W. A. Kellner (Organizer) Pustulatia(?) curupira (Rathbun 1874), Mutationellinae indet. D, Rhipidothyrididae sive Mutationellidae indet. B, Rhipidothyrididae sive Mutationellidae indet. D, Ter- MODE OF LIFE OF THE MACROFOSSILS FROM ebratulidae indet., Hexacrinites (?) sp. and Pentagonos- THE CABEÇAS FORMATION (DEVONIAN), PARNAÍBA tipes (?) sp.; (3) infaunal suspension feeders, represented BASIN, BRAZIL by Grammysioidea lundi (Clarke 1899), Grammysioidea 1 Cleber F. da Silva and sp. A and Tentaculites sp. (cf. T. eldregianus Rathbun 2 Deusana M.C. Machado 1874); (4) semi-infaunal suspension feeders, represented 1Estagiário do Laboratório de Comunidades Paleozóicas, De- by Spathella pimentana (Rathbun 1874); (5) infaunal de- partamento de Ciências Naturais, ECB, CCBS, UNI-RIO, Av. posit feeders, represented by Cucullella triquetra (Conrad Pasteur 428, Urca, Rio de Janeiro – RJ. 1841), Nuculites (Nuculites) aff. N. (N) oblongatus (Con- 2Laboratório de Comunidades Paleozóicas, Departamento de rad 1841) and Palaeoneilo sp. A; (6) mobile epibenthic Ciências Naturais, ECB, CCBS, UNI-RIO, Av. Pasteur 428, predator, represented by Metacryphaeus meloi (Carvalho Urca, Rio de Janeiro – RJ. et al. 1997); and (7) mobile epibenthic herbivore, repre- Presented by Diogenes de Almeida Campos sented by Plectonotus derbyi (Clarke 1899). These habits The Cabeças Formation belongs to the Canindé and their abundance agree with the previous suggestion Group and corresponds to the Devonian depositional se- that the Cabeças Formation was deposited in a shallow quence of the Parnaíba Basin. This unit is divided in two marine environment near the coast with moderated distur- members, from base to top: Passagem and Oeiras. The bance from marine currents. — ( December 20, 2001 ). Passagem Member is of marine-deltaic origin and yielded the macrofossils studied here; the Oeiras Member is afos- PALEOGEOGRAPHIC DISTRIBUTION OF NUCULITES siliferous and was deposited under fluvio-deltaic condi- CONRAD, 1841 AND CUCULLELLA McCOY, 1851 (MOL- tions. Fifteen taxa of the twenty-five known from the LUSCA/BIVALVIA) Passagem Member were found in the studied samples, as Deusana M.C. Machado1*and follows: six brachiopods, six bivalves, one trilobite and Vera M.M. Fonseca2** one tentaculitid. Besides those, five additional ones are 1 reported for the first time in this unit: two brachiopods Laboratório de Estudos de Comunidades Paleozóicas, Departa- (lingulid and Terebratulidae indet.), one inderminated bi- mento de Ciências Naturais, ECB, CCBS, UNI-RIO, Av Pasteur, valve and two crinoids [Hexacrinites (?) sp. and Pen- 428, Urca, Rio de Janeiro, RJ. 2 tagonostipes (?) sp.]. These species fell under seven Departamento de Geologia e Paleontologia, Museu Nacional / modes of life: (1) reclined epibenthic suspension feed- UFRJ, Quinta da Boa Vista s/n, São Cristóvão, Rio de Janeiro, ers, represented by Pleurochonetes comstocki (Rathbun RJ. 1874) and Mucrospirifer (?) pedroanus (Rathbun 1874); Presented by Alexander W.A. Kellner An. Acad. Bras. Cienc., (2002) 74 (2) 362 SUMMARY OF COMMUNICATIONS The genera Nuculites and Cucullella have origi- SOME DEVONIAN CHONETOIDEA (BRACHIOPODA) nated in different geographic areas, with the oldest record FROM THE AMAZON AND PARNAÍBA BASINS, found in the Llandovery (Lower Silurian). The former BRAZIL, AND THEIR STRATIGRAPHIC AND PALEO- was reported in Gondwana with two subgenera, Nu- GEOGRAPHIC IMPLICATIONS culites and Trilobonuculites, while the latter is found in Vera M.M. Fonseca1*and Avalonia. Due to environmental and tectonic factors, Deusana M.C. Machado2** those taxa became associated and distributed throughout 1Departamento de Geologia e Paleontologia, Museu Nacional / Gondwana, Avalonia, Kazakhistan and Laurussia from UFRJ, Quinta da Boa Vista s/n, São Cristóvão, Rio de Janeiro, the Late Silurian to the Late Devonian. The subgenus RJ. Trilobonuculites appeared firstly at the Pitinga Forma- 2Laboratório de Estudos de Comunidades Paleozóicas, Departa- tion, Amazon Basin, Brazil, and the subgenus Nuculites mento de Ciências Naturais, ECB, CCBS, UNI-RIO, Av Pasteur, is only recorded in the Silurian from the Tabuk Forma- 428, Urca, Rio de Janeiro, RJ. tion, Saudi Arabia. Cucullella was found in the Ross Presented by Diogenes de Almeida Campos Brook Formation of New Scotia, Canada. Since the Late Montsenetes Rachebouef and Pleurochonetes Isaac- Silurian (Ludlow), which is marked by a marine trans- son were identified in the Amazon and Parnaíba basins. gression, Trilobonuculites and Cucullella started to occur The first genus, represented by a new species, occurs in associated, invading other paleocontinents, confirmed by the Maecuru Formation (Lontra Member), at the Maecuru the presence of Cucullella in the Gondwana (Bolivia) and river (Pará State) and in the Pimenteira Formation, at Pi- Trilobonuculites in Avalonia (New Scotia). This suggests cos (Piauí State), represented by the species Montsenetes that the environment in these areas became more uniform cf. M. boliviensis Rachebouef. The second taxon is due to the rise of the sea level and the narrowing of the represented by Pleurochonetes comstocki Rathbun in the ocean Rheic. The Silurian-Devonian boundary is marked Ererê Formation, at the Monte Alegre dome (Pará State) by a marine regression followed by a new transgression, as well as in the Cabeças Formation at Picos and Oiti with maximum in the Frasian, and the collision of Aval- (Piauí State). Although benthonic organisms are not suit- onia/Baltica and Laurentia forming Laurussia. At this able for accurate dating, the presence of these genera point, the subgenus Nuculites reappeared. Still in the agrees with subsurface palynological datings that suggest Lower Devonian (Pragian-Emsian), the genus Nuculites an eifelian age for the macrofossiliferous horizons of the diversified, dominating by the subgenus Trilobonuculites, Maecuru and Ererê formations (Amazon Basin). The while Cucullella was only represented by a sole species Montsenetes species of the Maecuru Formation (simi- from Kazakhistan. In the Middle Devonian (Eifelian- lar to the Venezuelan M. notius) and the Pleurochonetes Givetian) the subgenus Nuculites predominated while species of the Ererê Formation (similar to the Bolivian P. Trilobonuculites was restricted to the Maecuru Formation anteloi) display compatible morphotypes with mesode- (Brazil). The only species of Cucullella dispersed to the vonian species of these genera. In the Parnaíba Basin oriental Laurussia and North and Occidental Gondwana. the species Montsenetes cf. M. boliviensis (Pimenteiras In the Late Devonian (Frasnian), the occurrence of these Formation) does not provide any specific age due to the taxa was restricted to the Armorican Massif, Northeastern controversy about its stratigraphical position in Bolivia. of Brazil and some doubtful occurrences in Bolivia. At However, the presence of Pleurochonetes comstocki in that time, the oceans deepened, dysaerobic and anoxic the Cabeças Formation suggests an eifelian age for the environments spread out and Gondwana and Laurus- fossiliferous horizons of the outcrops situated at the east- sia were approaching. These factors, associated with ern border of the Parnaíba Basin, where an age cannot thermal stress, led to extinction of several taxa at the Fras- be obtained by palynomorphs. The paleogeographic nian/Fammenian boundary, including those studied here. distribution of Montsenetes and Pleurochonetes shows The paleogeographic distribution of Nuculites and Cucul- changes in the connections between the Amazon and Par- lella agrees with the sea level curves and the movement naíba Basins during the Eifelian. The presence of one of the continents suggested to have taken place during species of Montsenetes similar to Venezuelan M. notius the Silurian and Devonian. — ( December 20, 2001 ). in the Amazon Basin, suggests that, during the lower ∗ E-mail: [email protected] Eifelian, the two areas had some connection, while in **E-mail: [email protected] the Parnaíba Basin the presence of Montsenetes cf. M. An. Acad. Bras. Cienc., (2002) 74 (2) SESSIONS OF THE ACADEMIA BRASILEIRA DE CIÊNCIAS 363 boliviensis indicated a connection between this area and delta systems, and was subsequently reworked by storms Bolivia. At the upper Eifelian, the Ererê Formation (Ama- and preserved in the sandstone layer where it was recov- zon Basin) and the Cabeças Formation (Parnaíba Basin) ered. — ( December 20, 2001 ). shared a significant part of their benthonic invertebrate fauna, showing a direct connection between them. One of the taxa shared is Pleurochonetes comstocki, which is THE IMPORTANCE OF FOSSIL TAXA IN THE KNOW- related to the Bolivian form P. anteloi Isaacson, suggest- LEDGE OF NEOPTERYGIAN INTERRELATIONSHIPS ing a link to the Bolivia area. — ( December 20, 2001 ). Paulo M. Brito, Lúcio P.C. Machado, ∗ Cesar R. Amaral and Diogo de Mayrinck E-mail: [email protected] Departamento de Biologia Animal e Vegetal, Universidade do **E-mail: [email protected] Estado do Rio de Janeiro. Presented by Alexander W.A. Kellner ON A FOSSIL LOBSTER (DECAPODA, MALACOS- Since the beginning of the 1970’s the Neopterygii TRACA, CRUSTACEA) FROM THE RIACHUELO FOR- are considered a monophyletic