DOI: 10.1590/23174889201500020001 FAST TRACK COMMUNICATION A new genus and species of enantiornithine bird from the Early Cretaceous of Brazil Um novo gênero e espécie de Ave enantiornithine do Cretáceo Inferior do Brasil Ismar de Souza Carvalho1*, Fernando E. Novas2, Federico L. Agnolín2,3, Marcelo P. Isasi2,3, Francisco I. Freitas4, José A. Andrade5 ABSTRACT: The fossil record of birds in Gondwana is almost res- RESUMO: No Gondwana, o registro fóssil de aves está praticamente tricted to the Late Cretaceous. Herein we describe a new fossil from restrito ao Cretáceo Superior. Neste estudo é descrito um novo fóssil da the Araripe Basin, Cratoavis cearensis nov. gen et sp., composed of an Bacia do Araripe, Cratoavis cearensis nov. gen. et sp., composto por um articulated skeleton with feathers attached to the wings and surroun- esqueleto articulado com penas conectadas às asas e circundando o corpo. ding the body. The present discovery considerably extends the tempo- A presente descoberta amplia consideravelmente o intervalo temporal de ral record of the Enantiornithes birds at South America to the Early registro das aves Enantiornithes na América do Sul ao Cretáceo Inferior. Cretaceous. For the first time, an almost complete and articulated ske- Pela primeira vez, um esqueleto articulado e quase completo de uma ave leton of an Early Cretaceous bird from South America is documented. do Cretáceo Inferior da América do Sul é documentado. KEYWORDS: Cratoavis cearensis nov. gen et sp.; Araripe Basin; PALAVRAS-CHAVE: Cratoavis cearensis nov. gen. et sp.; Bacia do Fossil bird. Araripe; Ave fóssil. INTRODUCTION enantiornithine birds from Presidente Prudente locality (Alvarenga & Nava 2005), and indeterminate birds from In South America, the Cretaceous avian record is com- Jales locality (Azevedo et al. 2007), both coming from posed of several taxa, including basal ornithothoracine the Adamantina Formation (Turonian-Santonian, Bauru birds, enantiornithes, and derived ornithurines, includ- Group). More recently, Candeiro et al. (2012) reported ing Neornithes-like taxa (Walker 1981, Alvarenga & from the Late Maastrichtian, fragmentary specimens refer- Bonaparte 1992, Chiappe 1993, 1996, Chiappe & Calvo able to indeterminated birds and enantiornithes from the 1994, Clarke & Chiappe 2001, Agnolin & Martinelli Marília Formation, at the Minas Gerais State. 2009, Agnolín 2010). Regarding the regional record, in There are also few reports concerning fossil birds from Brazil, only sparse mentions have been made up to the the Araripe Basin. All the available data comes from the date. Only three reports of Cretaceous birds are known for Santana Formation, Crato Member. Kellner (2002), Kellner the entire country, including unpublished indeterminate et al. (1991, 1994), Martins-Neto and Kellner (1988) and 1Geology Department, Universidade Federal do Rio de Janeiro – UFRJ, Rio de Janeiro (RJ), Brazil. E-mail: [email protected] 2Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’, Consejo Nacional de Investigaciones Científicas y Técnicas – CONICET, Buenos Aires, Argentina. E-mail: [email protected]; [email protected] 3Fundación de Historia Natural ‘Félix de Azara’, Universidad Maimónides, Buenos Aires, Argentina. E-mail: [email protected] 4Geopark Araripe, Crato (CE), Brazil. E-mail: [email protected] 5Departamento Nacional da Produção Mineral, Crato (CE), Brazil. E-mail: [email protected] *Corresponding author Manuscript ID: 30304. Received: 05/18/2015. Approved: 05/19/2015. 161 Brazilian Journal of Geology, 45(2): 161-171, June 2015 Cratoavis cearensis: a Cretaceous bird from Brazil Martill and Filgueira (1994) described feathers and plumes Piauí States (Martill 1993, Viana & Neuman 1999). with fi ne details such as colour patterns preserved as dark Th is lithostratigraphic unit is considered a fossil Lagerstätte, and light transverse bands. Although they are generally due the large amount and quality of its fossil preservation. assigned as belonging to Aves, probably are derived from Th e Crato Member fossils probably represent one of the several diff erent taxa, including some non-avian thero- most well-known terrestrial fl ora and fauna from the Aptian pod clades, such as Oviraptorosauria, Troodontidae or time. In fact, a large amount of faunistic remains has been Dromaeosauridae (Naish et al. 2007). On the other hand, described, including worms, insects, spiders, fi shes, basal osteological remains are restricted to two specimens. Th e fi rst lizards, turtles, crocodiles, non-avian dinosaurs and pos- one, an unlabelled specimen from Senckenberg Museum sible birds (see Martill et al. 2007). (Frankfurt, Germany) presents presumed carpal bones Th e Crato Member comprises essentially laminated associated with three asymmetrical feathers. Th e second, carbonate strata with some inter-bedded levels of fi ne held in a private collection in Japan, consists of a poorly sandstones, marls and clays. Th is succession is interpreted preserved articulated specimen, with an incomplete skull, as a lacustrine environment, in a rift basin context, that vertebrae, ilium, a possible ischium and a probable left constituted an important area for an abundant endemic hindlimb. Naish et al. (2007) considered that this second biota. Th e climate was at that time hot and arid. Th e con- specimen presents neural spines of the dorsal vertebrae and nection between South America and Africa as a single, the morphology of the centre of the dorsal vertebrae that large continental block did not allow a higher humidity, suggest a relationship with the euenantiornithines. More in what was the continental interior. During the time recently, Carvalho et al. (2015) described a nearly com- interval of the carbonate succession, where the new bird plete skeleton and associated feathers of a still unnamed species was found, occurred many important environmen- enantiornithine bird from the Crato Member (Santana tal changes. Th e climate gradually became more humid, Formation - Aptian, Araripe Basin). Th e association of as the tectonic events that drove the separation of South feathers and the almost complete skeleton points it as an America and Africa led to the origin of the equatorial exceptional fossil bird from the Early Cretaceous deposits. Atlantic Ocean (Carvalho 2004, Carvalho & Pedrão 1998, Th e aim of the present paper is to coin a new name for Medeiros et al. 2014). this specimen, as well as to make some comparisons with Th e distribution of the laminated limestones of Crato other enantiornithine birds. Member throughout the Araripe Basin, allowed Martill et al. (2007) to estimate the depositional area as a water body with a minimum extent of some 18,000 km2. Th e brack- GEOLOGICAL CONTEXT ish water was an alkaline environment, in which occurred some hypersaline stages represented by carbonates with Th e southern hemisphere was deeply changed during pseudomorphs of halite crystals. Menon and Martill (2007) the Early Cretaceous times. Th e intense tectonic activity, observed that the lack of reworked horizons within as related to the initial stages of the Gondwanic crust rup- much as 13 meters of laminite suggests considerable water turing, led to the disappear, but also to the fl ourish of new depth and deposition probably under anoxic botton water. ecological niches. Th ese events are registered in the interior Th e integration of lithological and petrographic evidences of Northeastern region of Brazil, in intracratonic basins by Heimhofer et al. (2010) indicates that the bulk of Crato developed along pre-existing Precambrian structural trends. Member limestone was formed via authigenic precipita- One of these sedimentary areas is the Araripe Basin, which tion of calcite from within the upper water column, most has 12,200 km2 and its Early Cretaceous history spans from probably induced and/or mediated by phytoplankton and Berriasian to Albian times (Fig. 1). Th is basin was mainly picoplankton activity. Th e isotopic evidence indicates a fi lled, during Early Cretaceous, with clastic and chemical shift from closed to semi-closed conditions towards a more rocks (Carvalho 2000). Th e lithostratigraphy of the basin open lake system during the onset of laminate deposition has been discussed by many authors (Beurlen 1963, 1971; of the Crato Member. Cavalcanti & Viana 1992, Assine 1992, Ponte 1992, Martill Th e dating of this interval was presented by Rios-Netto 1993, Martill & Wilby 1993, Viana & Neuman 1999, et al. (2012). The biostratigraphical framework to the Assine 2007). Alagoas Stage, based on palynological analyses proceeded Th e new fossil was collected in the Crato Member on 167 samples from 14 wells drilled at the Eastern portion (Aptian) of Santana Formation (Fig. 2). Th e outcrops are of the Araripe Basin, showed only the P-270.2 and P-280.1 distributed around Chapada do Araripe plateau, in the subzones of Regali and Santos (1999). Th ese subzones are southern Ceará, western Pernambuco and south-eastern assigned to the late Aptian (119 – 113 Ma). 162 Brazilian Journal of Geology, 45(2): 161-171, June 2015 Ismar de Souza Carvalho et al. m 11 Carbonate fine sandstone Marl 10 Laminated Limestone Massive Calcareous (Matracão) 9 Cratavis cearensis Gastropods 8 Fishes Insects 7 Plants Halite pseudomorphs Climbing ripples 6 5 4 3 2 1 Figure 1. Location map of the Araripe Basin in the context of the Cretaceous Brazilian Northeastern intracratonic basins and stratigraphical profi le from the location where the fossil was collected.