The Pirabas formation (Early Miocene from Brazil) and the Tropical Western Central Atlantic Subprovince
A Formação Pirabas do Brasil (Mioceno inferior) e a subprovíncia tropical do Atlântico Noroeste Central
Orangel Aguilera SocorroI, Eduardo Tavares PáesII
IMuseu Paraense Emílio Goeldi/Ministério da Ciência, Tecnologia e Inovação. Belém, Pará, Brasil
IIUniversidade Federal Rural da Amazônia. Belém, Pará, Brasil
ABSTRACT
The Neogene Tropical Western Central Atlantic-South American faunal assemblage from the Pirabas Formation (Early Miocene) has specific and unique features, which distinguishes it from the rest of the Proto-Caribbean Subprovince in diversity, paleoceanographic condition and ecosystems. Principal component analysis (PCA) distinguished three groups of localities with similar faunas (Group A: ilha de Fortaleza, Colônia Pedro Teixeira and Praia de Fortalezinha; Group B: Estação Agronômica, ilha de Marajó, Turiacu, Baixo Parnaíba, Aricuru and Salinópolis; Group C: Capanema B-17 Mine) and five different depositional facies (surf zone, beach, lagoons, tidal channel and tidal delta), in agreement with previous geological studies showing heterogeneous paleoenvironments among the outcrops. These heterogeneous lithostratigraphic sequences suggest different members, and may be related to different ages along the Pirabas sequence. The Neogene Northwestern Atlantic Subprovince is erected to encompass this entire geographical area.
Keywords: Neogene. Pirabas. Paleoecology. Paleobiogeography. Proto-Caribbean.
RESUMO
A assembleia da fauna Neógena Tropical Sul Americana da Formação Pirabas (Mioceno inferior) possui características específicas e únicas que a distinguem do resto das subprovíncias Proto-Caribenhas em diversidade, condições paleoceanográficas e ecossistemas. A análise de componentes principais distingue três grupos de localidades com faunas similares (Grupo A: ilha de Fortaleza, colônia Pedro Teixeira e praia de Fortalezinha; Grupo B: Estação Agronômica, ilha de Marajó, Turiaçu, baixo Parnaíba, Aricuru e Salinópolis; Grupo C: Mina B-17, Capanema) e cinco diferentes fácies deposicionais (zona de arrebentação, praia, lagoa, canal de maré e delta de maré), corroborando estudos geológicos prévios, que mostram uma série de paleoambientes heterogêneos nestes afloramentos. Essa sequência litológica heterogênea sugere a presença de vários membros, que poderiam ser correlacionados a diferentes idades ao longo da sequência da Formação Pirabas. A denominação de subprovíncia tropical do Atlântico Noroeste Central é proposta para o Neógeno dessa área geográfica.
Palavras-chave: Neógeno. Pirabas. Paleoecologia. Paleobiogeografia. Proto-Caribe.
]]> INTRODUCTION
Since the 19th century, the fossiliferous limestone studied by Ferreira Penna (1876) has yielded a high species diversity from the exclusively Cenozoic deposits (Figure 1) along the northern Atlantic coast of South America in Brazil (Pará, Maranhão and Piauí states).
The early contributions of White (1887) and Maury (1925) were the basal references on the Pirabas Formation (Early Miocene from Brazil), particularly in mollusk, bryozoan and coral research, followed by the contributions of Petri (1954, 1957) on foraminifera, Beurlen (1958), Brito (1971, 1972, 1977) and Martins-Neto (2001) on crustaceans, Santos (1958, 1967) on echinoids, Santos & Travassos (1960) and Santos & Salgado (1971) on fishes, Paula-Couto (1967) and Toledo & Domning (1989) on sirenians. Many other references, summarized in Rossetti & Góes (2004) and Távora et al. (2010) provide additional descriptions, records and/or reviews of different fossil taxa.
All of these authors suggest close relationships between the faunal assemblages from the Pirabas Formation and the Caribbean Neogene fauna, based on qualitative analysis, species co-occurrence and personal conclusions. However, based on fossil fish faunas, Aguilera et al. (2011 and in progress) conclude that the Pirabas Formation has a distant relationship with the Gatunian Province in the Caribbean region. This is true even when the Pirabas Formation is compared with the Early Miocene Husillo and Cojimar formations from Cuba, the Mao Formation from the Dominican Republic, the Cantaure and Castillo (lower section) formations from Venezuela, the Tuira Formation from Panama, the Brasso Formation from Trinidad, the Kendeace Formation from Grenada, and the Viche Formation from Ecuador.
The topics considered here are the faunal composition, the influence of the Tropical Atlantic water mass on the North Brazilian Current (Johns et al., 1998, 2002), the high tidal range (Beardsley et al., 1995; DHN, s. d.), the eustatic sea level changes (Haq et al., 1988; Carter, 1998; Kominz et al., 2008) and the sea level fluctuations in northern Brazil (Rossetti, 2001), the early Miocene age of the Pirabas Formation, and the geographic location of the Pirabas Basin previous to the present configuration of the Caribbean Sea.
The main lithostratigraphic and paleoenvironmental interpretation of the Pirabas Formation is that of Góes et al. (1990), Rossetti (2001) and Rossetti & Góes (2004). These authors present a representative vertical profile (Figure 2), synthesizing the depositional sequence and characterizing the Pirabas Formation as consisting of carbonate rocks from offshore platform deposits (grainstone and consolidated packstone, stratigraphic wackestone-packstone and laminated mudstone), littoral facies (shoreface/foreshore), marginal lagoons and restricted platform (gray to olive mudstone and conglomeratic sandstone), and mangrove estuarine lagoons (dark mudstone, massive or laminated). The Early Miocene age assignment of the Pirabas Formation follows Petri (1957), Fernandes (1984), Ferreira et al. (1978), Fernandes & Távora (1990) and Távora & Fernandes (1999).
]]>
Recent research (S. A. F. Costa, A. E. A. Santos Junior, H. M. Moraes-Santos & O. Aguilera, personal communication) described a heterogeneous lithostratigraphic sequence along a section in the Capanema B-17 Mine, and proposed five lithofacies: surf zone, beach, lagoons, tidal channel and tidal delta, which would describe an littoral system with wave and tidal influence.
These heterogeneous sequences and the faunal assemblages recorded in different outcrops suggest that different members should be recognized, and accurate geochronological research may reveal different ages within the Pirabas sequence.
Based on this heterogeneous lithostratigraphic profile and the diverse fossil record (which includes 214 invertebrates and vertebrates from 21 outcrop-localities), our objective is a quantitative analysis aimed at producing an appropriate interpretation to support future research on the context of geochronology, paleoenvironments, paleobiogeography and stratigraphic review for the Pirabas Formation.
METHODS
The data presented were taken from published literature (White, 1887; Maury, 1925; Petri, 1954, 1957; Beurlen, 1958; Santos, 1958, 1967; Santos & Travassos, 1960; Paula-Couto, 1967; Santos & Salgado, 1971; Brito, 1971, 1972, 1977; Fernandes, 1981; Toledo & Domning, 1989; Martins-Neto, 2001), including a variety of invertebrates (bryozoans, echinoids, mollusks and crustaceans) and vertebrates (sirenians and fishes), recompiled in a recent paper by Távora et al. (2010), and consulted during a general overview of the fossil collection in the Museu Paraense Emílio Goeldi (MPEG) repository. Some original taxonomic names listed by Távora et al. (2010) may need to be revised. However, the genus-level data can be used with confidence in the present analysis. The description of the local geology and stratigraphy follows Góes et al. (1990), Rossetti (2001) and Rossetti & Góes (2004). Field study of the main sections at Atalaia beach, Ponta do Castelo, Fazenda, Fortalezinha and the Capanema B-17 Mine was conducted as part of the Museu Emílio Goeldi Vertebrate Paleontology Project. The data were standardized at the generic level, as is common in this kind of study (Foote & Miller, 2007). This procedure served also to diminish distortions caused by preservation and sampling biases, endemic groups, and nomenclatural uncertainties.
]]> We grouped localities according to the outcrops studied, which are deemed good geographic and paleoenvironmental representatives of the early Miocene Pirabas Formation sections. A few samples of taxa in certain localities are biased or absent due to lack of preservation or study. The binary data matrix includes 214 fossil invertebrates and vertebrates from 21 outcrop-localities (Table 1).
One of the most important multivariate methods of data analysis is PCA (Ferreira et al., 1999; Malinowski, 1991) based on the correlation between variables. it aims to group these correlated variables, generating a new set of variables called principal components (PC) onto which the data is projected. These PC are built as linear combination of original variables and have the important property of being completely uncorrelated. The first new axis is chosen in such a direction that it maximizes the variance along the axis, the second must be chosen orthogonal to the first one and the direction to describe as much variance left as possible so on.
The Principal Components Analysis (PCA) uses the calculated covariance and variance between localities; for this reason this is a Q-PCA according to Fasham (1977). The Q-PCA analysis was run using the free software PAST (Hammer et al., 2001), and the taxonomic groups was expressed in the PCAs planes using the concentration ellipse level of 30%. Following Jackson et al. (1989), the size effect of the linear relationship between the PCA axis 1 and the relative frequency of species occurrence were established with the largest occurrence. The coefficient from each PCA are present in the Table 2.
The confidence ellipses of genera groups were formed by computing the three following quantities using the PAST software (Hammer et al., 2001), as proposed by Abdi et al. (2009): (1) the coordinates of the center of the ellipse of each group in the factorial plane (Axis II and Axis III), (2) the angle between the major axis of the ellipse and the first dimension of the plane, and (3) the relative size of the minor axis compared to the major axis of the ellipse. To perform these procedures one must set the center of the ellipse at the center of mass of the points. Thereafter, the ratio between the minor axis and the major axis is calculated as the ratio of the second eigenvalue to the first eigenvalue. Finally, the angle of rotation is given by the first eigenvector. For a 30% confidence interval, the lengths of the axes of the ellipse are set to ensure that the ellipse comprehends 30% of the points. The value of 30% was chosen for visual clarification so as to avoid overlapping the ellipses and better identify the centroids of taxonomic groups in factorial plane.
RESULTS AND DISCUSSION
The Early Miocene faunal assemblage identified in northern Brazil is called here the Proto-Caribbean Pirabas fauna (not Caribbean), based on the nature of this fauna and because the Caribbean Sea proper was only formed after the Pacific and Atlantic were completely isolated in the Pliocene (Coates et al., 1992, 2004; Coates & Obando, 1996). The paleobiogeographic model for the southern Caribbean comprises the lower Miocene-lower Pleistocene Gatunian Province and the middle Pleistocene-upper Pleistocene Caribbean Province (Landau et al., 2008). According to this system the Neogene Tropical Western Central Atlantic Subprovince can be erected to encompass this entire geographical area.
In our assessment, the Proto-Caribbean Pirabas fauna is arranged in three faunal groups and five different facies. Faunal group A, includes the isolated vector of ilha de Fortaleza (IFOR), Colônia Pedro Teixeira (CTEI), and Praia de Fortalezinha (PFORT). This group exhibits a pattern of co-occurrence and singularity of fossil faunas indicated by the assemblages of gastropods, echinoids, crustaceans and vertebrates (Figure 3, left projection). Group B includes vector from Estação Agronômica (ESTA), Salinópolis (SALI), ilha de Marajó (IMAR), Turiacu (TURI), Baixo Parnaíba (BPAR) and Aricuru (ARIC). All of these exhibit a pattern of co-occurrence of bryozoans, bivalves, and gastropods in lesser proportion (Figure 3, right projection). An independent vector from the Capanema B-17 Mine (MB17), without a significant relationship with Groups A and B, forms Group C.
]]> The close relationship among the bryozoans in Group B is clear. However, the condition in Group A is closely related to the co-occurrence of echinoids, crustaceans and vertebrates.
The facies, called previously by Petri (1957) Castelo (shallow coastal marine, reaching 30 m deep), Caneco (littoral coastal marine to transitional basin border, reaching 10 m deep) and Baunilha Grande (mangrove marginal lagoons), are the basis for review and proposing the subdivision of the Pirabas Formation according to the isolated vector or vector complex into the following five facies: Ilha de Fortaleza (IFOR), Estação Agronômica (ESTA), Aricuru (ARIC), Capanema (MB17) and Colônia Pedro Teixeira (CTEI) (Figure 3).
CONCLUSION
The Neogene Tropical Western Central Atlantic-South American faunal assemblage from the Early Miocene Pirabas Formation has specific and unique features,which distinguish it from the rest of the Proto-Caribbean Subprovince in diversity, paleoceanographic condition and ecosystems.
The proposed Tropical Western Central Atlantic Subprovince is supported by the faunal assemblage analysis for the Proto-Caribbean Pirabas Formation, which is an exclusively Cenozoic unit cropping out along the northern Atlantic coast of Brazil in South America.
As a result of the PCA analysis, three faunal groups and five different facies were observed, in agreement with previous geological studies that indicated heterogeneous paleoenvironments along the section. These heterogeneous sequences in this lithostratigraphic unit could support a division into different formal or informal members, and/or indicate different ages of parts of the Pirabas Formation.
This study showed the diagnostic faunal assemblages and priority areas for future research in taxonomy, taphonomy, geochemistry, stratigraphy needed to establish detailed relationships between the different outcrops assigned to the Pirabas Formation. The paleoenvironments and paleobiogeography must be combined with complementary geochronologic research to provide absolute age determinations.
ACKNOWLEGEDMENTS
]]> The Museu Paraense Emílio Goeldi, the Universidade Federal Rural do Pará and the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil, support this research. We thank to Daryl Domning for the early reviewing and English corrections, Maria inês Ramos, Heloísa Moraes-Santos and Maria de Lourdes Ruivo for support under the CNPq project, Francileila Jatene Cavalcante for the library assistance, the Editors Board from the Boletim do Museu Paraense Emílio Goeldi for allowing the reproduction (modified from Rossetti & Góes, 2004 and Távora et al., 2010) of the lithostratigraphic section and the outcrops map. The authors would like to thank two anonymous reviewers for comments and suggestions that improved the manuscript.
REFERENCES
ABDI, H., J. P. DUNLOP & L. J. WILLIAMS, 2009. How to compute reliability estimates and display confidence and tolerance intervals for pattern classifiers using the Bootstrap and 3-way multidimensional scaling (DISTATIS). Neuroimage 45(1): 89-95.
AGUILERA, O., M. I. RAMOS, E. PÁES, S. COSTA & M. SÁNCHEZ-VILLAGRA, 2011. The Neogene tropical American fish assemblage and the paleobiogeography of the Caribbean region. Swiss Journal of Palaeontology 130: 217-240.
BEARDSLEY, R., J. CANDELA, R. LIMEBURNER, W. GLEYER, S. J. LENTZ, B. M. CASTRO, D. CACCHIONE & N. CARNEIRO, 1995. The M2 Tide on The Amazon Shelf. Journal of Geophysical Research 100(C2): 2283-2319.
BEURLEN, K., 1958. Contribuição à Paleontología do estado do Pará. Crustáceos decápodes da Formação Pirabas. Boletim do Museu Paraense Emílio Goeldi, Nova Série Geologia 5: 1-48.
BRITO, I. M., 1971. Contribuição ao conhecimento dos Crustáceos decápodes da Formação Pirabas. I - Brachyura Brachyrhyncha. Anais da Academia Brasileira de Ciências 43(suplemento): 489-498.
BRITO, I. M., 1972. Contribuição ao conhecimento dos Crustáceos decápodes da Formação Pirabas. II - Brachyura Ocypodidae. Anais da Academia Brasileira de Ciências 44(1): 95-98.
BRITO, I. M., 1977. Novas ocorrências de cirrípedes balanomorfos na Formação Pirabas, Mioceno Inferior do Estado do Pará. Anais da Academia Brasileira de Ciências 49(3): 465-468.
CARTER, R. M., 1998. Two models: global sea-level change and sequence stratigraphic architecture. Sedimentary Geology 122(1-4): 23-36.
COATES, A. G., J. B. C. JACKSON, L. S. COLLINS, T. M. CRONIN, H. T. DOWSETT, L. M. BYBELL, P. Y. JUNG & J. OBANDO, 1992. Closure of the Isthmus of Panama: the near-shore marine record of Costa Rica and western Panama. Geological Society of America Bulletin 104(7): 814-828.
COATES, A. G., L. S. COLLINS, M.-P. AUBRY & W. A. BERGGREN, 2004. The Geology of the Darien, Panama, and the late Miocene-Pliocene collision of the Panama arc with northwestern South America. Geological Society of America Bulletin 116(11-12): 1327-1344.
COATES, A. G. & J. A. OBANDO, 1996. The geologic evolution of the Central American Isthmus. In: J. B. C. JACKSON, A. F. BUDD & A. G. COATES (Eds.): Evolution and environment in tropical America: 21-56. University of Chicago Press, Chicago.
DIRETORIA DE HIDROGRAFIA E NAVEGAÇÃO (DHN). Previsões de Maré. [s.d.]. Available at: <https:/www.mar.mil.br/dhn/chm/tabuas/index.htm>. Accessed on: November 2011.
FASHAM, M. J. R., 1977. A comparison of nonmetric multidimensional scaling, principal components and reciprocal averaging for the ordination of simulated coenoclines and coenoplanes. Ecology 58: 551-561.
FERNANDES, A. C. S., 1981. Contribuição à Paleontologia do estado do Pará - Um novo Flabellum (Anthozoa - Scleractinia) na Formação Pirabas. Boletim do Museu Paraense Emílio Goeldi, Nova Série Geologia 24: 1-7.
FERNANDES, J. M. G., 1984. Paleoecology of Formation Pirabas, Pará State. Anais da Academia Brasileira de Ciências 1: 330-340.
FERNANDES, M. J. G. & V. A. TÁVORA, 1990. Estudo dos Foraminíferos da Formação Pirabas procedentes do furo CB-UFPa-PI (85), município de Capanema, Estado do Pará. Anais do 36o Congresso Brasilerio de Geologia 1: 470-475.
FERREIRA, C. S., A. C. M. MACEDO & J. F. P. ASSIS, 1978. A Formação Pirabas no Estado do Pará. Novo registro de subsuperfície: Belém (Furo 4be-01-Pa, Cprm). Anais da Academia Brasileira de Ciências 50(3): 427.
FERREIRA, M. C., C. G. FARIA & E. T. PAES, 1999. Oceanographic characterization of northern São Paulo Coast: a chemometric study. Chemometrics and Intelligent Laboratory Systems 47: 289-297.
FERREIRA PENNA, D. S., 1876. Breves notícias sobre os sambaquis do Pará. Arquivo do Museu Nacional 1: 85-89.
FOOTE, M. & A. I. MILLER, 2007. Principles of Paleontology. 3rd ed. Freeman and Company, New York.
GÓES, A. M., D. ROSSETTI, A. NOGUEIRA & P. M. TOELDO, 1990. Modelo deposicional preliminar da Formação Pirabas no Nordeste do Estado do Pará. Boletim do Museu Paraense Emilio Goeldi, série Ciências da Terra 2: 3-15.
HAMMER, O., D. A. T. HARPER & P. D. RYAN, 2001. PAST: Paleontological Statistics Software Package for Education and Data Analysis. Palaeontologia Electronica 4(1): 9. Available at: <http://palaeo-electronica.org/2001_1/past/past.pdf>. Accessed on: October 2011.
HAQ, B. V., P. R. VALI & J. HARDENHOL, 1988. Mesozoic and Cenozoic chronostratigraphy and eustatic cycles. In: C. K. WILGUS, B. S. HASTINGS, C. A. ROSS, H. POSAMENTIER, J. VAN WAGONER, C. G. ST. C. KENDALL (Eds.): Sea Level Changes - an Integrated Approach: 71-108. Society of Economic Paleontologists and Mineralogists (Special Publication, 42), Tulsa, Oklahoma.
JACKSON, D. A., K. M. SOMERS & H. H. HARVEY, 1989. Similarity coefficients: measures of co-occurrence and association or simply measures of occurrence. The American Naturalist 133(3): 436-453.
JOHNS, W. E., T. N. LEE, R. C. BEARDSLEY, J. CANDELA, R. LIMEBURNER & B. CASTRO, 1998. Annual cycle and variability of the North Brazil Current. Journal of Physical Oceanography 28(1): 103-128.
JOHNS, W. E., T. L. TOWNSEND, D. M. FRATANTONI & W. D. WILSON, 2002. On the Atlantic inflow to the Caribbean Sea. Deep-Sea Research Part I 49: 211-243.
KOMINZ, M. A., J. V. BROWNING, K. G. MILLER, P. J. SUGARMAN, S. MIZINTSEVA & C. R. SCOTESE, 2008. Late Cretaceous to Miocene sea-level estimates from the New Jersey and Delaware coastal plain coreholes: an error analysis. Basin Research 20(2): 211-226.
LANDAU, B., G. VERMEIJ & C. MARQUES DA SILVA, 2008. Southern Caribbean Neogene palaeobiogeography revisited. New data from the Pliocene of Cubagua, Venezuela. Palaeogeography, Palaeoclimatology, Palaeoecology 257(4): 445-461.
MALINOWSKI, E. R., 1991. Factor analysis in chemistry. 3rd edition: 1-422. Wiley, New York.
MARTINS-NETO, R. G., 2001. Review of some Crustacea (1sopoda and Decapoda) from Brazilian deposits (Paleozoic, Mesozoic and Cenozoic) with descriptions of new taxa. Acta Geológica Leopoldensia 24(52-53): 237-254.
MAURY, C. J., 1925. Fósseis terciários do Brasil com descrição de novas formas Cretáceas: 1-665. Serviço Geológica e Mineralógico do Brasil (Monografia 4), Rio de Janeiro.
PAULA-COUTO, C., 1967. Contribuição à paleontologia do estado de Pará. Um sirênio na formação Pirabas. Atas do 1o Simpósio sobre a Biota Amazônica 1: 345-357.
PETRI, S., 1954. Foraminíferos fósseis da Bacia de Marajó. Boletim da Faculdade de Filosofia, Ciências e Letras da Universidade de São Paulo (Geologia) 134(11): 1-70.
PETRI, S., 1957. Foraminíferos miocênicos da Formação Pirabas. Boletim da Faculdade de Filosofia, Ciências e Letras da Universidade de São Paulo (Geologia) 216(16): 1-79.
ROSSETTI, D., 2001. Late Cenozoic sedimentary evolution in northeastern Pará, Brazil, within the context of sea level changes. Journal of South American Earth Sciences 14(1): 77-89.
ROSSETTI, D. & A. GÓES, 2004. Geologia. In: D. ROSSETTI & A. GÓES (Ed.): O Neógeno da Amazônia Oriental: 13-52. Museu Paraense Emílio Goeldi (Coleção Friederich Katzer), Belém.
SANTOS, M. E. C. M., 1958. Equinóides miocênicos da Formação Pirabas. Boletim da Divisão de Geologia e Mineralogia 179: 1-24.
SANTOS, M. E. C. M., 1967. Equinóides miocênicos da Formação Pirabas. Atas do 1o Simpósio sobre a Biota Amazônica 1: 407-410.
SANTOS, R. S. & S. TRAVASSOS, 1960. Contribuição à paleontologia do Estado do Pará. Peixes fósseis da Formação Pirabas. Monografia da Divisão de Geologia e Mineralogia, Departamento Nacional da Produção Mineral 16: 1-35.
SANTOS, R. S. & M. S. SALGADO, 1971. Contribuição à paleontologia do Estado do Pará. Novos restos de peixes da Formação Pirabas. Boletim do Museu Paraense Emílio Goeldi, Nova Série Geologia 16: 1-13.
TÁVORA, V. & J. M. FERNANDES, 1999. Estúdio de los foraminíferos de la Formación Pirabas (Mioceno Inferior), Estado de Pará, Brasil, y su correlación con faunas del Caribe. Revista Geológica de America Central 22: 63-74.
TÁVORA, V., A. A. SANTOS & R. N. ARAÚJO, 2010. Localidades fossilíferas da Formação Pirabas (Mioceno Inferior). Boletim do Museu Paraense Emílio Goeldi. Ciências Naturais 5(2): 207-224.
TOLEDO, P. M. & D. P. DOMNING, 1989. Fossil Sirenia (Mammalia: Dugongidae) from the Pirabas Formation (Early Miocene), northern Brazil. Boletim do Museu Paraense Emílio Goeldi, série Ciências da Terra 1(2): 119-146.
WHITE, C. A., 1887. Contribuições à Paleontologia do Brasil. Archivos do Museu Nacional 7: 1-273.
Autor para correspondência: ]]>
Orangel Aguilera Socorro.
Museu Paraense Emílio Goeldi/Ministério da Ciência,
Tecnologia e Inovação.
Coordenação de Ciências da Terra e Ecologia.
Departamento de Geociências.
Av. Perimetral, 1901 – Terra Firme. Belém, PA, Brasil.
CEP 66077-830.
(orangel.aguilera@gmail.com)
Recebido em 19/09/2011
Aprovado em 03/04/2012