This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier’s archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright http://www.elsevier.com/copyright Author's personal copy Paleontology, sedimentology and paleoenvironment of a new fossiliferous locality of the Jurassic Cañadón Asfalto Formation, Chubut Province, Argentina Oscar F. Gallego a,*, Nora G. Cabaleri b, Claudia Armella b, Wolfgang Volkheimer c, Sara C. Ballent d, Sergio Martínez e, Mateo D. Monferran a, Diego G. Silva Nieto f, Manuel A. Páez g aMicropaleontología, Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste y Área Paleontología, Centro de Ecología Aplicada del Litoral, Consejo Nacional de Investigaciones Científicas y Técnicas, C.C.128, C.P. 3400 Corrientes, Argentina b Instituto de Geocronología y Geología Isotópica, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina c Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales, Centro Científico e Tecnológico, Consejo Nacional de Investigaciones Científicas y Técnicas, C.C. 330, 5500 Mendoza, Argentina dDivisión Paleontologia Invertebrados, Facultad de Ciencias Naturales y Museo, Pasaje Teruggi s/n, Paseo del Bosque, La Plata 1900; Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina eDpto. Evolución de Cuencas, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay f Servicio Geológico Minero Argentino, Instituto de Geología y Recursos Minerales, Av. Julio A. Roca 651, 10� Piso, C1067ABB Buenos Aires, Argentina gComisión Nacional de Energía Atómica, Regional Patagonia, C.C. 178, Parque Industrial, 9100 Trelew, Chubut, Argentina a r t i c l e i n f o Article history: Received 15 September 2009 Accepted 8 November 2010 Keywords: Paleontology Sedimentology Late Jurassic Cañadón Asfalto Formation Patagonia Argentina Palabras Clave: Paleontología Sedimentología Jurásico Tardío Formación Cañadón Asfalto Patagonia Argentina a b s t r a c t A new Late Jurassic assemblage of “conchostracans”, ostracods, bivalves and caddisfly cases from the locality “Estancia La Sin Rumbo”, Chubut Province (Patagonia, Argentina) is recorded. The fossils occur in theupper part of anoutcropping45mthickvolcaniclastic lacustrine sequence of yellowish tuffs and tuffites of the Puesto AlmadaMember,which is the uppermember of the CañadónAsfalto FormationwithU/Pb age of 161 � 3 Ma. The sequence represents one sedimentary cycle composed of a (lower) hemicycle of expansion and a (higher) hemicycle of contraction of the water body. The invertebrates lived in small freshwater bodies during the periods of expansion of the lake. The occurrence of a great number of small spinicaudatans, associated with mud-cracks, is evidence of dry climatic conditions and suggests several local mortality events. The spinicaudatan record of the fushunograptideorthestheriid (component of the Eosestheriopsis dianzhongensis fauna) and the presence of Congestheriella rauhutiGallego and Shen, suggest a Late Jurassic (Oxfordian to Tithonian) age. Caddisfly cases are recorded for the first time in the Cañadón Asfalto Basin. � 2010 Elsevier Ltd. All rights reserved. r e s u m e n Se presenta una nueva asociación de “conchostracos”, ostrácodos, bivalvos y capullos de tricópteros del Jurásico Tardío de la localidad “Estancia La Sin Rumbo”, provincia del Chubut (Patagonia, Argentina). Los fósiles se hallaron en la parte superior de una secuencia volcaniclástica lacustre de tobas y tufitas amarillas de 45 m de espesor, del Miembro Puesto Almada, que es el miembro superior de la Formación Cañadón Asfalto, con una edad radimétrica (U/Pb) de 161 � 3 Ma. La secuencia representa un ciclo sedimentario compuesto de un hemiciclo (inferior) de expansión y un hemiciclo (superior) de contracción del cuerpo de agua. Los invertebrados mencionados vivieron en pequeños cuerpos de agua dulce durante los períodos de expansión del lago. La presencia de un gran número de pequeños “con- chostracos”, asociados con grietas de desecación, indica condiciones de clima seco y sugiere varios eventos locales de mortandad. El registro de “conchostracos” “fushunográptidos-orthoestheriidos” (componentes de la fauna de Eosestheriopsis dianzhongensis) y la presencia de Congestheriella rauhuti Gallego y Shen, sugieren una edad jurásico tardío (Oxfordiano a Tithoniano). Capullos de tricópteros son registrados por primera vez en la Cuenca de Cañadón Asfalto. � 2010 Elsevier Ltd. All rights reserved. * Corresponding author. Tel./fax: þ54 3783 454417. E-mail addresses: ofgallego@live.com.ar (O.F. Gallego), cabaleri@ingeis.uba.ar (N.G. Cabaleri), armella@ingeis.uba.ar (C. Armella), volkheim@mendoza-conicet.gov.ar (W. Volkheimer), sballent@fcnym.unlp.edu.ar (S.C. Ballent), smart@fcien.edu.uy (S. Martínez), monfdm@gmail.com (M.D. Monferran), dsilva@mecon.gov.ar (D.G. Silva Nieto), paez_manuel@yahoo.com (M.A. Páez). Contents lists available at ScienceDirect Journal of South American Earth Sciences journal homepage: www.elsevier .com/locate/ jsames 0895-9811/$ e see front matter � 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.jsames.2010.11.001 Journal of South American Earth Sciences 31 (2011) 54e68 Author's personal copy 1. Introduction Previous records of Jurassic invertebrates from Patagonia, Argentina (Tasch and Volkheimer, 1970; Vallatti, 1986) are from the lower section (Las Chacritas Member) of the Cañadón Asfalto Formation, at the classical localities situated south of the Cerro Cóndor village (Fig. 1). Gallego et al. (2010) described Con- gestheriella rauhuti Gallego and Shen, the first spinicaudatan from the upper section (Puesto Almada Member) of the same unit. Earlier records of Jurassic continental invertebrate faunas from Argentina are known only from two Patagonian areas (Deseado Massif: La Matilde Formation, and Extra-andean Chubut: Cañadón Asfalto Formation). Piatnitzky (1933, 1936), Feruglio (1949) and Frenguelli (1949) reported the first Jurassic invertebrates (as “Estheria“ sp.) from Chubut and Santa Cruz provinces (for more data see Gallego, 1994). The first descriptions of spinicaudatans from the Cañadón Asfalto Formation are those of Tasch and Volkheimer (1970). At the moment, fourteen species of Jurassic spinicauda- tans have been described, ten of them from the Cañadón Asfalto Formation (Tasch and Volkheimer, 1970; Vallatti, 1986; Gallego, 1994 and Gallego et al., 2010). In 1994, one of us (WV) and Helga Smekal (Bariloche Paleon- tological Association) collected samples at the locality “Estancia La Sin Rumbo”, near the Chubut provincial road N� 12 (km 88.7), 41 km north of Cerro Cóndor village (GPS 43� 160 49.2” S, 69� 070 45.3” W) (Fig. 1). These original samples include spinicaudatans, bivalve and gastropod mollusks, ostracods and rare trichopteran fossil cases. They are assigned to the Cañadón Asfalto Formation. Their exact stratigraphic provenance was unresolved until now. During December 2007 and March 2009, our research team carried out detailed collections and the study of the sedimentary sequence. The first studies of the Cañadón Asfalto Formation of Extra- andean Patagonia in the middle Chubut river valley are those of Piatnitzky (1936), who named this sequence “Estratos con Estheria” (Beds with Estheria). Later on, Flores (1948) described it as “Sección Esquistosa de la Serie Porfírica” (Schistosy Section of the Porphy- ritic Series). Feruglio (1949) included it into the upper section of the Complex of Sierra de Olte, making up part of the “Chubutense”. Frenguelli (1949) performed the first studies of the fossil flora of this unit, indicating a Callovian-Oxfordian age, by comparison with the Middle to Upper Jurassic La Matilde Formation. Stipanicic et al. (1968) defined it formally as the Cañadón Asfalto Formation and Nullo (1983) divided it into a lower and an upper section. Later Silva Nieto et al. (2003) divided the formation into the Las Chacritas and Puesto Almada members. Detailed stratigraphic descriptions were realized by Cabaleri et al. (2008b) and Cabaleri et al. (2010b). In earlier papers (Figari and Courtade, 1993; Rauhut, 2006) the Cañadón Calcáreo Formation (Proserpio, 1987) is correlated with the upper part of the Cañadón Asfalto Formation (“Estratos de Almada”; Musacchio, 1995, p. 180). New palynologic and radio- metric data indicate a Late Jurassic age for the Puesto Almada Member and an Early Valanginian age for the middle section of the Cañadón Calcáreo Formation (Cabaleri et al., 2010b,c; Volkheimer et al., 2009). Homovc et al. (1991), Figari and García (1992), Figari and Courtade (1993), Figari et al. (1992, 1996) interpreted the tec- tosedimentary evolution of the Cañadón Asfalto Basin as different stages (youth and mature) of a half-graben basin. These authors distinguish four megasequences corresponding to different moments of the rift system. They include in the Megasequence II the Cañadón Asfalto Superior Formation, the Cañadón Calcáreo Formation and the “Estratos de Almada” with an age from Middle Kimmeridgian to Middle Hauterivian for Figari y Courtade (1993, p. 68) and Middle Kimmeridgian-Berriasian for Figari (2005, p. 39). Later, Silva Nieto et al. (2002a, b) published the geologic map of Cerro Cóndor and a genetic-structural analysis of the Cañadón Asfalto Formation, defining a pull-apart type basin for the area of Cerro Cóndor. Cabaleri and Armella (1999, 2005), and Cabaleri et al. (2005, 2006, 2008a, 2010a,b) and Silva Nieto et al. (2007) pre- sented a detailed study of the Cañadón Asfalto Formation, its depocenters, paleoenvironments and paleoclimates. The important paleontologic record of the Cañadón Asfalto Formation was the object of important publications, including the analysis of the taphofloras (Stipanicic et al., 1968; Stipanicic and Bonetti, 1969; Cortés and Baldoni, 1984; Baldoni, 1990; Escapa et al., 2008). Assemblages of palynomorphs were studied by Volkheimer et al. (2008) and invertebrates by Tasch and Volkheimer (1970), Vallatti (1986), Gallego (1994), Genise et al. (2002), Gallego and Cabaleri (2005) and Gallego et al. (2010). Calcareous microfossils were studied by Musacchio et al. (1990) and Musacchio (1995). The vertebrate record of the Cañadón Asfalto Formation was recently reviewed by Volkheimer et al. (2008, p. 90). The objectives of this paper are to communicate a new locality of paleontological and sedimentologic interest in the Cañadón Asfalto Basin (Puesto Almada Member of the Cañadón Asfalto Formation), with first records of insect (caddisfly) fossil cases, associated with spinicaudatans, ostracods and bivalve mollusks and to define the paleoenvironments during the silting of the Cerro Cóndor Depo- center and characterize the border of the paleolake. 2. Geologic setting In Extraandean Chubut, several depocenters have been described for the Cañadón Asfalto Basin (Cabaleri et al., 2006; Silva Nieto et al., 2007) and interpreted as pull-apart type basins. The sequences representing the fillings of these depocenters consist of lacustrine limestones (Cabaleri and Armella, 1999), associated with pyroclastic deposits and basaltic rocks of the Las Chacritas Member (Silva Nieto et al., 2003; Cabaleri et al., 2008a,b; 2010a,b). The silting of the depocenters is principally represented by tuffs, intercalated with laminated rhythmites, pelites and sandstones of the Puesto Almada Member. The pre-Mesozoic basement (Fig. 2) is composed by Precambrian metamorphic and intrusive rocks of the Cushamen Formation and Late Paleozoic mesosilicic plutonites of the Mamil Choique Formation and equivalents. These formations are unconformably covered by the fluvio-deltaic deposits of the Las Leoneras Formation and equivalents (Depositional Cycle 0 of Figari et al., 1992) and, in the study area, by mesosilicic to basic volcanites of the Lonco Trapial Formation (Lesta and Ferello, 1972), of early Middle Jurassic age, from which Silva Nieto (2005) obtained a radiometric age (K/Ar) of 173.1 � 9.4 Ma (Aalenian). At this locality, the Puesto Almada Member (Cañadón Asfalto Formation) is unconformably covered by Cretaceous sandstones and quartzitic conglomerates of the Campanian/Maastrichtian Paso del Sapo Formation (Lesta and Ferello, 1972), of marine littoral origin and also corresponding to braided rivers of a deltaic plain. This sequence interfingers laterally with fossiliferous sandstones, pelites and gray and greenish claystones of estuarine environ- ments, corresponding to the Lefipán Formation (Lesta and Ferello, 1972). During the Cretaceous (BarremianeCampanian) new extensional forces produced the fracturing, basculating and rota- tion of blocks, together with the reactivation of pre-existing faults (Figari and Courtade, 1993), initiating a new subsidence of the basement, regulating the deposition of the Chubut Group (Mega- sequence III; Figari, 2005), and producing an angular unconformity over the Cañadón Asfalto Formation. The facies of the filling of these basins correspond to prograding fluvial cycles of the Los Adobes Formation (Barremian; Codignotto et al., 1979). The posterior thermal subsidence and a pyroclastic cycle of large areal O.F. Gallego et al. / Journal of South American Earth Sciences 31 (2011) 54e68 55 Author's personal copy Fig. 1. Location map and geologic sketch of the Cerro Cóndor area. O.F. Gallego et al. / Journal of South American Earth Sciences 31 (2011) 54e6856 Author's personal copy extension correspond to the Cerro Barcino Formation (Aptian to Campanian; Codignotto et al., 1979). The Paleogene of the study area is represented by tuffs and yellowish-white sandy tuffites of the Sarmiento Group, of Oligo- cene age and by Miocene basalts of the El Mirador Formation. The Quaternary is characterized by Pleistocene piedmont deposits and Holocene alluvial, colluvial, eolian and landslide deposits (Fig. 1). 3. Sedimentology In the studied locality crops out a 45 m sequence of tuffs and tuffites of the upper Member (Puesto Almada Member) of the Cañadón Asfalto Formation. The tuffs are prevailing (Fig. 3). The base is covered. In the lower section a sequence of 5.8 m of tuffites can be recognized, forming beds of up to 3 m of thickness. There are thin intercalations of claystones withmud-cracks. The only recognizable structures are wave stratifications and scarse borings. This tuffite has a complex microstructure in which can be distinguished a groundmass composed by amorphous tuffaceous material, ceo- lites and carbonatic cement. The moderately sorted particles (30%) are angular, middle grained, composed by plagioclase, orthoclase, quartz and fragments of volcanic glass and amorphous tuffy material of brown-yellowish color, with disperse oxids of Fe (Fig. 4A). Fig. 2. Generalized stratigraphic chart of the northwestern part of the Cerro Cóndor depocenter, showing the position of the studied section (Puesto Almada Member of the Cañadón Asfalto Formation) and the section at the type locality of the Puesto Almada Member at Estancia El Torito locality. At Estancia La Sin Rumbo locality is outcropping the lowermost part of the Puesto Almada Member, while at the type locality is outcropping the upper part of the members. O.F. Gallego et al. / Journal of South American Earth Sciences 31 (2011) 54e68 57 Author's personal copy Fig. 3. Columnar section of the Puesto Almada Member of the Cañadón Asfalto Formation at the “Estancia La Sin Rumbo” locality. O.F. Gallego et al. / Journal of South American Earth Sciences 31 (2011) 54e6858 Author's personal copy Levels of clear brown-yellowish tuff (1.40 m), disposed in beds of 30e40 cm, showing a complex laminated structure with a vitreous microcrystalline groundmass, with microaggregates of clay continuing upwards. The particles are pumaceous fragments, fresh and angular crystals of plagioclase, quartz, orthoclase and concentric radial carbonatic ooids (Fig. 4B). Above these levels of tuff, and with an erosive contact, a chan- nelled deposit of sandy tuffites continues, forming a lens of 8 m of length and a thickness varying between 3.40 m and 1.60 m, with oblique stratification, which pinches out at the edges. The micro- structure is massive; the groundmass, of clear brown color, is composed of amorphous tuffaceous material, clay, devitrificated Fig. 4. Photomicrographs of the lithofacies and a hand sample present in the Puesto Almada Member. A: Groundmass amorphous tuffaceous material, iron oxides, plagioclase, orthoclase, quartz and volcanic glass fragments. CASN1. B: Pumiceous fragment in contact with quartz; plagioclase, orthoclase rounded in vitreous groundmass. CASN2. C: Intraclast, siliciclasts, vitreous groundmass and argillaceous microgranules. CASN3. D: Microstructure complex with a lamination produced by the differential content of argillaceous material. The groundmass is homogeneous, composed by glass with fluidal structure and aligned microgranules of clay. CASN5. E: Fine levels of tuffites of red color. CASN 6. F: Hand sample with the mudcraks and spinicaudatans (MPEF-PI1187). CASN 6. G: Root bioturbation. CASN4. H: Microstructure complex, the groundmass is homogeneous. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article) O.F. Gallego et al. / Journal of South American Earth Sciences 31 (2011) 54e68 59 Author's personal copy glass and carbonatic cement. The medium-grained clasts (45%) are well sorted, angular to rounded and composed of quartz, ortho- clase, plagioclase, microcline, micas, carbonatic intraclasts and rounded vitroclasts of microcrystalline silica, pumaceous fragments and argillaceous microgranules (Fig. 4C). A sequence of 34 m of tuffs, deposited in beds of 0.50e1.0 m, of yellowish brown color, wave stratification, bottommarks andmud- cracks continues upwards. There are characteristic intercalations of thin and fine discontinuous black pumaceous levels. The micro- structure is complex, with a lamination produced by the differential content of argillaceous material. The groundmass is homogeneous, composed of glass with fluidal structure and aligned microgranules of clay (Fig. 4D). In the above described sequence the intercalations of fine levels of 4e20 cm of tuffites of red color (Fig. 4E) are characteristic, with bottommarks, mud-cracks (Fig. 4F) and root bioturbation (Fig. 4G). Their microstructure is complex and the groundmass is homoge- neous (Fig. 4H), with argillaceous material of circular birefringent fabric and crumbs of disperse iron oxides. The clasts are fine sand (20%), with moderate sorting, composed of subangular and sub- rounded crystals of quartz, orthoclase, plagioclase and pumaceous fragments (Fig. 4E). 4. Paleontology and age 4.1. Paleontology 4.1.1. Insects The insect recordof the studied section is composed of immature stages of Trichoptera, commonly known as caddisflies. The fossils reported here are composed of trichopteran larval cases (Genise et al., 2002; Monferran et al., 2008, 2009). The Order Trichoptera is the second largest lineage of aquatic insects based on the total species number (11,500 extant and 642 fossil species, Grimaldi and Engel, 2005; Ivanov and Sukatsheva, 2007). This group has small free-flying adult forms with moth-like feature. The aquatic (rarely semiaquatic or terrestrial) larval forms can live free or make larval cases to protect themselves. These cases may be constructed with different kinds of materials (fragmentary or complete) including plants (leaves, stems and seeds), animals (ostracod and spinicau- datan carapaces or snail and bivalve shells, fish scales or bones) and minerals (sand or clay grains). The selection of the construction material is mainly conditioned by the availability in the environ- ment or with larval preferences. Recent trichopteran larval forms inhabit both lentic and lotic (with water currents) environments. The fossils reportedhere are preserved as imprints or compressed moulds. The cases are mainly constructed by fragments of carapaces or less frequently complete carapaces of spinicaudatans (fushu- nograptids), complete ostracod valves (mainly Penthesilenula sary- tirmenensis) and sand grains. The composition of the constructed material is monotypic; in these examples they only use spinicauda- tan, ostracod and sand grains. Thus they are tentatively assigned to different ichnogenera respectively: Conchindusia Vialov and Sukatcheva (Fig. 5A,G), Ostracindusia Vialov (Fig. 5B,H) and Terrin- dusia Vialov (Fig. 5I) (Monferran et al., 2008, 2009). These kinds of fossils are studied as traces or ichnofossils; rarely are they preserved with the body inside them, making it difficult to attribute them to particular extant families. The taxonomic position of the case builder cannot be determined with certainty at a level lower than suborder, based on the case structure. The oldest larval caddisfly cases are found in the Middle Jurassic of Siberia and Mongolia. Some of them resemble the tubes of the modern Suborder Hydropsychina, and others show no differences from the cases of the Suborder Phryga- neina (Sukatsheva, 1998; Ivanov and Sukatsheva, 2007). 4.1.2. Spinicaudatans Since the description of the spinicaudatan faunas of the Caña- dón Asfalto Formation by Tasch and Volkheimer (1970) and Vallatti (1986), our knowledge on this group of bivalved crustaceans has increased noticeably. Seven species have been described in the mentioned papers, but now more than fourteen species are recor- ded in the Depocenter Cerro Cóndor (Gallego and Cabaleri, 2005; Gallego et al., 2010). The new localities are: “Estancia El Torito”, “Puesto Limonao”, “Cañadón de los Chivos”, “Cañadón Los Loros”, “Cañadón Las Chacritas”, “Cañadón Asfalto”, “Cañadón Lahuincó”, “Cañadón Miyanao” and in this contribution “Estancia La Sin Rumbo”. This fauna is mainly composed of species of the families Euestheriidae and Eosestheriidae and secondarily Afrograptidae and Anthronestheriidae. Gallego et al. (2010) restudied the speci- mens described by Vallatti (1986) from the Cerro Bayo locality, at the east of Puesto Almada (now: Estancia El Torito), and assigned them to the Family Afrograptidae (Congestheriella rauhuti). This species occurs together with species of the families Anthro- nestheriidae (Pseudestherites sp.) and Euestheriidae. The beds that crop out in the Sierra de la Manea and Cañadón de los Chivos localities also carried this fauna. The spinicaudatans Euestheriidae Euestheria volkheimeri, Fushunograptidae “Lioestheria” sp., Eosestheriidae E. taschi, “L.” patagoniensis and, in addition, a new species have been recognized from the Las Chacritas Member. In the Puesto Almada Member the identified spinicaudatans are: Eosestheriidae, Afrograptidae Con- gestheriella rauhuti, Anthronestheriidae Pseudestherites sp. and Euestheriidae Euestheria (Gallego and Cabaleri, 2005; Gallego et al., 2010). The spinicaudatans studied from this new locality are characterized by: ovate outline, small dimensions (3e3.8 mm length and 2.2e3 mm width; width/length ratio 0.5e0.97), short and arched dorsal margin, anterior and posterior margins with equal convexity and length, subcentral umbo and growth bands ornamented with irregular thick radial lirae with numerous thin cross-bars (knit lattice-like reticulation with small punctae) in the dorsal-medium (upper third) of the carapace, changing to straight thick radial lirae with few cross-bars restricted to the upper half of the growth band in the ventral third of carapace and terminal radial lirae are expanding into subtriangular shape part. The morpho- logical features (outline and ornamentation) and size of the cara- pace, allow us to assign this species probably to the Family Fushunograptidae (orthestheriids) (Fig. 5A,C). The fushunograptid of the studied locality is related to older species such as “Liograpta” zavattieri Gallego from the Cerro de Las Cabras Formation (Middle Triassic; Gallego, 1999), “Lioestheria” striolatissima Rusconi from the Potrerillos-Cacheuta formations (Upper Triassic; Gallego, 1999) and probably also to Polygrapta troncosoi Gallego from the Upper Triassic La Coipa and Río Biobío beds from Chile (Gallego and Covacevich, 1998; Gallego et al., 2005). It is also related to Middle/Upper Jurassic fushunograptid species, as “Lioestheria” malacaraensis Tasch from the La Matilde Formation (Middle-Upper Jurassic; Tasch, 1987) from Argentina and Orthestheria (Migransia) ferrandoi Herbst from Tacuarembó Formation (Upper Jurassic -Lower Cretaceous; Shen et al., 2004) from Uruguay. The Fushunograptidae (orthestheriid) spinicaudatan from “Estancia La Sin Rumbo” locality may represents a new genus and species of the family. Nevertheless, these specimens are somewhat approaching to Qinghaiestheria Wang from the Upper Jurassic Hongshuigou Formation in Qinghai (northwestern China) and Penglaizheng Formation in Sichuan (southwestern China) (Wang, 1983; Shen and Chen, 1982; Li, 2004) in its ornamentation, but the latter has serrated structure along the lower margin of the growth lines. O.F. Gallego et al. / Journal of South American Earth Sciences 31 (2011) 54e6860 Author's personal copy 4.1.3. Ostracods The ostracods of the studied section are moderately preserved. They are abundant,mostly thin shelled and large to very large in size. The association is of low diversity and is composed of articulated valves (closed carapaces) filled with material that does not allow for observation of internal features. Specimens preserved as internal moulds are also frequent. Three genera have been identified, each represented by a single species: Penthesilenula sarytirmenensis (Sharapova) of Mandelstam (1947) (Fig. 5D), Theriosynoecum bar- rancalensis minor (Musacchio et al., 1990) and Mandelstamia sp. (Fig. 8). The genus Penthesilenula Rossetti and Martens, 1998 (Dar- winuloidea, Darwinulidae) comprises two species groups: the incae- group and the africana-group. Penthesilenula sarytirmenensis is a large-sized darwinulid (more than 0.900 mm in length), with an elongate carapace and with the posterior part broadly enlarged and nearly straight, the left valve overlapping the right one along the entire periphery and the external surface smooth. A pointed caudal internal tooth in the left valve (which characterizes the incae-group) is not visible in the studied carapaces. The species has beendescribed from the Middle Jurassic of the Mangishlaka Peninsula, ex USSR (Mandelstam, 1947) and also was recognized from the Middle and Late Jurassic of several localities in China (Li, 1985; Zheng, 1995; among others) and south-eastern India (Govindan, 1975). In Argentina,Musacchio et al. (1990) andMusacchio (2001) recognized Fig. 5. Invertebrate fauna from “Estancia La Sin Rumbo” locality, Puesto Almada Member, Cañadón Asfalto Formation (Extraandean Patagonia, Argentina). A: Fushunograptid spinicaudatan and Conchindusia, MPEF-PI 1178. B: Penthesilenula sarytirmenensis and Ostracindusia, MPEF-PI 1179. C: Fushunograptid, MPEF-PI 1180. D: Penthesilenula sar- ytirmenensis, MPEF-PI 1181. E: Fushunograptid and Penthesilenula sarytirmenensis MPEF-PI 1182. F: cf. Diplodon MPEF-PI 1183. G: Conchindusia, MPEF-PI 1178. H: Ostracindusia, MPEF-PI 1185. I: Terrindusia, MPEF-PI 1186. J: Gastropoda indet MPEF-PI 1184, Scale bars: A, B, E, F, G-J. ¼ 5 mm, C ¼ 1 mm, D ¼ 0.5 mm. O.F. Gallego et al. / Journal of South American Earth Sciences 31 (2011) 54e68 61 Author's personal copy it from the Late Jurassic of “Estratos de Almada”, El Barrancal (near to Paso de Indios) and El Capricho (near to Cerro Cóndor), Chubut Province. Theriosynoecum barrancalensis minor (Cytheroidea, Lim- nocytheridae) is large in size (0.800e0.900 mm in length), dimor- phic, subrectangular in lateral view, with obliquely rounded anterior margin, very compressed anterior peripheral area and truncated posterior margin; subtriangular to pyrifom in dorsal view. Lateral surface reticulate, with numerous diminute papillae and with longitudinal striae along the ventral area. It presents a conspicuous anterior subcentral sulcus and a less deep second sulcus in front of it. This species is recognized from the Late Jurassic of “Estratos de Almada”, El Barrancal (near to Paso de Indios) and El Capricho (near Cerro Cóndor), Chubut Province, Argentina (Musacchio et al., 1990; Musacchio, 2001). The genus Mandelstamia Ljubimova (1955) (Cytheroidea) is known from the Late Jurassic of Europe, ex USSR and southwestern Asia. Mandelstamia sp. (often as moulds) is elon- gate oval in lateral view, with straight dorsal margin, feeble anterior subcentral sulcus and lateral surface covered with small tubercles. Musacchio (2001) mentioned Mandelstamia in Late Jurassic sedi- ments from a locality near to Gan Gan (Chubut Province). Populations of Penthesilenula sarytirmenensis and Ther- iosynoecum barrancalensis minor comprise large numbers of adults and of juvenile instars corresponding to the early ontogeny of the species. 4.1.4. Mollusks The mentions of mollusks from the Cañadón Asfalto Formation are those of Volkheimer (in Tasch and Volkheimer, 1970, p. 19) and Martínez et al. (2007). The first authors note the gastropod Pota- molithus and the bivalve Palaeomutela from some beds of the Las Chacritas Member, while the second group mentions the bivalves cf. Diplodon, Sphaeridae and Corbiculidae of the Las Chacritas Member and cf. Diplodon and the gastropod “Viviparus” of the Puesto Almada Member. In the studied section, cf. Diplodon and a large indeterminant gastropod are found (Fig. 5F,J). Specimens are small, preserved as moulds, without signs of fractures. Valves are of rather uniform size, dissarticulated, mostly parallel to the stratification surface, with random orientation, forming concentrations (one or two beds about 1 cm thick). Since they are moulds, abrasion cannot be properly evaluated but it seems not to have been important enough to leave some evidence. It is difficult to establish the proportion of convexity of valves up or down, because the moulds suffered some compression. According to the visualization or not of growth bands, there are present both modalities. The bivalves are comparable to Diplodon, based on overall morphology; but lack important characters such as the hinge, umbonal sculpture, ormuscle scars, obligate to be cautious with the identification. Shape and size are very homoplasic characters in the Unionoida (Parodiz and Bonetto, 1963; Graf, 2001), and there is a high intraspecific variation of shell shape (e.g. Ortmann, 1920). 4.2. Age Age is based on lithostratigraphic correlation, biostratigraphic evaluation of the invertebrate record and radiometric dating. 1) Lithostratigraphic correlation with well-dated sections out- cropping in nearby areas within the same depocenter Cerro Cóndor The lithology and sedimentary characteristics of the studied section are comparable to those of the type section of the Puesto Almada Member of the Cañadón Asfalto Formation, illustrated in Fig. 7, taking into account that the type locality corresponds to a more central position in the depocenter, with a major participa- tion of fine grained sediments deposited in deeper areas of the lake, while the “Estancia La Sin Rumbo” area represents amarginal facies with prevailing tuffites and tuffs (Fig. 3). 2) Biostratigraphic evaluation of the invertebrate record registered in the studied section (Fig. 8). The spinicaudatan association of Euestheriidae and Eosesther- iidae (from the Las Chacritas Member) support a Middle to Late Jurassic age for the bearing levels. In change, the association of Congestheriella rauhuti (Afrograptidae), Pseudestherites sp. (Anthronestheriidae), and Fushunograptidae (from the Puesto Almada Member) indicates a Late Jurassic (or even somewhat younger) age for the bearing sequence. The spinicaudatan fauna from this locality reports the probable presence of a new genus and species of the Family Fushunograptidae, which resembles the genus Qinghaiestheria. Fushunograptids (Qinghaiestheria sichuanensis Chen and Shen, Q. chuanzhongensis Chen and Shen, Q. suboblonga Chen and Shen and Orthestheria sp.) are secondary components of the typical Late Jurassic “Eosestheriopsis dianzhongensis fauna” of Fig. 6. Block diagram of the “Estancia La Sin Rumbo” locality. In the first plane, the position of the lake. The surrounding of the lake represents the silting of the basin (without scale). O.F. Gallego et al. / Journal of South American Earth Sciences 31 (2011) 54e6862 Author's personal copy Fig. 7. Columnar section of the Puesto Almada Member at the type locality (Estancia El Torito). O.F. Gallego et al. / Journal of South American Earth Sciences 31 (2011) 54e68 63 Author's personal copy the middle Jehol biota from Asia (Chen, 1999; Chen et al., 2007; Li, 2004; Li et al., 2007). Qinghaiestheria was originally recorded from the Hongshuigou Formation (Mangya, Qinghai) and also occurs in the Penglaizhen Formation (Sichuan Basin, southwestern China). Both are considered to be of Late Oxfordian in age. It is approaching to Polygrapta biaroensis Defretin-Lefranc (ascribed to Migransia by Chen and Shen, 1977) from the Upper Jurassic Stanleyville Series (Congo Basin, Africa) in its shape, growth line with serrated structure and radial lirae. The Hongshuigou Formation yields Sinoestheria, which strongly resembles Palaeolimnadiopsis lombardi Defretin-Lefranc (Stanleyville Series), in its large and thin carapace, recurved postero-dorsal margin, large polygonal reticulation and stout growth line with a row of tubercles. The Stanleyville Series is dated as Kimmeridgian in age (Defretin-Lefranc, 1967). Fig. 8. Range chart showing the stratigraphic distribution of the spinicaudatan species (and others related from northern South America and Africa), caddisfly case ichnogenera and ostracod species from the Middle-Upper Jurassic from Patagonia, Argentina. Spinicaudatan: Orthestheria (Migransia) malacaraensis from the La Matilde Formation (Deseado Massif, Argentina), Congestheriella lualabensis ancestral form and Nemestheria (Zhestheria) sp. from the Cañadón Calcáreo Formation (Extraandean Patagonia, Argentina); Congestheriella olsoni from La Quinta Formation (Venezuela); Congestheriella sp. from the Barro Basin (Brazil), Congestheriella rauhuti from Cañadón Asfalto and Cañadón Calcáreo formations (Extraandean Patagonia, Argentina), Pseudestherites spp. from other stratigraphic units from Extraandean Patagonia (Argentina); Fushunograptidae (“orthestherid”) from the Cañadón Asfalto Formation (Extraandean Patagonia, Argentina) and Congestheriella lualabensis from the Stanleyville Series (Central Africa). Caddisfly cases: Conchindusia, Ostra- cindusia and Terrindusia ichnogenera from the Cañadón Asfalto (Extraandean Patagonia, Argentina) and La Matilde formations (Deseado Massif, Argentina) including the distri- bution of other known species of the world. Ostracods: Penthesilenula sarytirmenensis, Theriosynoecum barrancalensis minor and Mandelstamia sp. O.F. Gallego et al. / Journal of South American Earth Sciences 31 (2011) 54e6864 Author's personal copy The two ostracod species of the studied section belong to the Theriosynoecum barrancalensis Zone of Late Jurassic age (Musacchio, 1989, 2001; corresponding toMegasequence II:mature hemigraben, Figari, 2005). This ostracod zone, originally named Bisulcocypris barrancalensis, is herein renamed Theriosynoecumbarrancalensis. The genus Bisulcocypris Pinto and Sanguinetti is currently referred to as a junior synonym of Theriosynoecum Branson (see Do Carmo et al., 2004 and references herein). Due to theuncertain identificationof thebivalves (cf.Diplodon sp.) they are not useful for biostratigraphic considerations. Anyway, the known fossil record does not contradict the proposed age. The genus is known at least since the Middle Jurassic in Argentina (La Matilde Formation;MortonandHerbst, 2001), and is recordedalso in the Late Jurassic-Early Cretaceous Tacuarembó Formation of Uruguay (Martínez et al., 1993; Perea et al., 2009). The considerations about the uncertainty of the identification taking into account only overall shape must be applied also in these last cases. In North America, is recorded in the Triassic (Good, 1989 and references). Finally, the spinicaudatan genus Qinghaiestheria was recovered from the Penglaizhen and Hongshuigou formations (Late Jurassic, China), also the last formation yields a Palaeolimnadiopseids spi- nicaudatan. In addition, similar associations are recorded in the Stanleyville Series (Kimmeridgian, Late Jurassic, Africa) and the La Matilde Formation (Callovian-Oxfordian, Middle to Late Jurassic) from Patagonia Argentina. In the Puesto Almada Member (at the Estancia Fossati locality) is recorded an undescribed species of the Family Palaeolimnadioseidae. Also, the previous data offer new evidence for the paleontological and paleobiogeographical spini- caudatan relationships between central Africa and South America (ASA province) as suggested by Gallego and Martins-Neto (2006) and Gallego et al. (2010). This assemblage allows us to compare our association with the “Eosestheriopsis dianzhongensis fauna” (Chen et al., 2007; Li, 2004) and the other fauna mentioned above that support a Late Jurassic age for the bearing levels (Puesto AlmadaMember, Cañadón Asfalto Formation). The range chart (Fig. 8) shows the distribution of the spinicau- datans and related forms, adding the range of the three ichnoge- nera of the caddisfly fossil cases and the ostracod species from the Puesto Almada Member (Cañadón Asfalto Formation). All data of the chronologic distribution support an Oxfordian - Tithonian age for this Member. 3) Radiometric dating (K/Ar) based on studies of idiomorphic biotites of volcanic tuffs. Radiometric dating (K/Ar) of biotites from a thin layer of volcanic tuffs (Age: 147.1�3.3 Ma from the upper part of the Puesto Almada Member at its type locality indicates a Tithonian age (Koukharsky, M. in Cabaleri et al., 2010a). The new U/Pb age (161 � 3 Ma) in zircons present in tuffites of the Puesto Almada Member from the locality “Estancia La Sin Rumbo” suggests that the sedimentation began during the Oxfordian (Cabaleri et al., 2010b). 5. Paleoenvironmental model The studied profile shows a simple environmental evolution, exemplified by deposits of tuffs and tuffites dissected by channelled tuffitic sandstones. The sedimentary regime of the basin was modified by an important pyroclastic supply. The pyroclastic deposits are the product of ash fall and input of this fluvially reworked material into the water body. The lithologic character indicates that the pyroclastic material (Tiercelin, 1991) may have been deposited inmarginal areas of the Cerro Cóndor paleolake and represents a gradual silting of the depocenter (Fig. 6). The facies pattern is reflected by the presence of water levels which register a cycle of expansion (or high lake level) and contraction of the lake (Fig. 3). The major episode of expansion is documented in the basal 10 m of the section, interrupted by brief episodes of contraction, with the characteristic systems of mud-cracks. Expansion is rep- resented by levels of tuffites and channelled tuffitic sandstones, produced by transport during the input of water in the marginal areas. These conditions are demonstrated by the presence of sedi- ments reworked by waves of low energy (Platt and Wright, 1991) and the presence of bottommarks which indicate soft currents. The input of water is produced by tractive currents and the input of sediments by small streams (creeks). The fine grained levels of claystones would indicate crevasse splays on the marginal areas, temporarily exposed and later covered by littoral facies. In the lower hemicycle (expansion) can be observed rare horizontal borings (Scoyenia ichnofacies) in tuffitic levels. Zhang et al. (1998) observed that these borings are originated during the low level of the lake, but they are preserved during the moments of flooding and expansion of the water body under conditions of low energy, characteristic for marginal lacustrine facies. The contraction is prevailing in the upper 35 m of the section and is interrupted by brief episodes of expansion. During the contraction the water level begins to be reduced by increasing aridity and silting, due to the high pyroclastic supply, which produced the filling of the lake. The change to dry climatic condi- tions is indicated by desiccation of the marginal areas and the development of a system of mud-cracks, which are frequent in the levels of fine grained sediments, previously remobilized by soft waves. It can be deduced that the climate is modifying gradually towards dryer conditions in the upper parts of the section. The spinicaudatans are the most abundant (freshwater) inver- tebrate group recorded in the Cañadón Asfalto Formation, as well as in the La Matilde Formation (Middle to Late Jurassic of the Deseado Massif). They inhabit small and temporary water bodies and littoral areas of lakes, with freshwater to brackish water conditions and water temperatures from 13� to 25 �C. They can survive under extreme values as 1� or 41 �C and pH conditions from neutral to alkaline. The record of spinicaudatans is shared by both strati- graphic units of the Cañadón Asfalto Formation (Las Chacritas and Puesto Almada members). These taxa differ in morphologic features of the carapace, but mainly in their dimensions, probably related to an environmental (ecologic) control. The fauna of the Las Chacritas Member, composed by Eustheriidae and Eosestheriidae, is characterized by large spinicaudatans with multiple and wide spaced growth lines, which correspond with large-deep perennial water bodies, where those populations could develop. The absence of fish records in this sequence implies the minor predator-prey pressure supported by the spinicaudatan assemblage. On the other hand, the fushunograptid from the “Estancia La Sin Rumbo” locality with one of the smallest carapace sizes in the Cañadón Asfalto fauna, probably shows a response to the high fish diversity recor- ded in other coetaneous levels of this formation (Bordas, 1942; Bocchino, 1967; López-Arbarello et al., 2002; López-Arbarello, 2004). Nevertheless, another possibility is that this carapace size may be related to a shallow ephemeral and marginal water body, occasionally with high energy impact as suggests the sedimento- logic analysis. The dry climatic conditions indicated by the presence of mud-cracks are also supported by the co-occurrence with a great number of small spinicaudatans in these levels, which suggest a mass mortality event (Fig. 4F). The taphonomic evidence indicates that the caddisfly cases are autochthonous. Theyoriginated in a shallowmarginal lake systemof the upper Cañadón Asfalto Formation (Puesto Almada Member), underwarm and semiarid environmental conditions. In this context O.F. Gallego et al. / Journal of South American Earth Sciences 31 (2011) 54e68 65 Author's personal copy it is interesting to mention the observation of Jarzembowski (1995) of the uncommon presence of the caddisflies in the Wealden of England, consistent with a warm climate and some salinity. At the “Estancia La SinRumbo” locality, both ichnogeneraConchindusia and Ostracindusia are preserved together with ostracods and spinicau- datan valves used by them for constructing their cases. Penthesilenula and Theriosynoecum are typical fresh water ostracods. Recent Penthesilenula have been found in awide range of aquatic environments, but including semi-terrestrial and terrestrial habitats. The type species P. incae is bottom-dweller, especially abundant in coarse-grained sediments rich in organic matter. It has also been found in shallowhot springs, pools and channels in largely dry lakes, rich in algae and of 10e20 cm depth, at the southern Altiplano in Perú, Bolivia andArgentina (Rossetti et al.,1996; Laprida et al., 2006). Other living species of Penthesilenula have been recovered from both saturated and unsaturated terrestrial habitats, such as leaf litter in forests (Pinto et al., 2004). These characteristics agree with the low diversity of the association and the fact that the percentage of the total individuals made up by the two most abundant species (P. sarytirmenensis and T. barrancalensis minor) reaches near 90% of the total of specimens, which characterizes freshwater associations (Whatley, 1983). The presence in both species of large numbers of adults and of juvenile instars well back into the ontogeny of the species can be interpreted as the product of a lowenergy regime, typified (inmodernanalogues) byHistogramof Type A of Whatley (1983). The studied microfauna is mainly composed of carapaces (articulated valves). It is argued that, if high percentages of adult specimens are articulated, these have not been subject to any great amount of post-mortem transportation (which is valid in our study of the Cañadón Asfalto Formation) or this indicates rapid burial before biologic activity and/or tissue decay which can bring about disarticulation. However, the fact that certain species have been encountered as carapaces and others as valves, as demonstrated by Whatley (1988) may be due to biologic and morphologic reasons of the species in question rather than tapho- nomic ones. Also, there exists the strong possibility that the adductor muscles (which close the valves) of some species contract on death while in others they relax. Darwinulids, as many fresh- water species, reproduce by parthenogenesis. They are brooders (eggs and the first two or three instars are retained in the carapace). For that reason it is important how tightly the valves can close. They have marginal structures such as internal teeth (in the left valve in Penthesilenula) which prevent them from closing toomuch and thus crushing eggs and juveniles and the brood pouch becomes obscured (Martens et al., 2002). However, closing valves must be safe enough to prevent them from opening which would cause the death of the animal and progeny. Unionoids are fresh water bivalves, and ideally live with inter- mediate current velocities, where the fine fraction of sediment is present but water is clean and well oxygenated, pH slightly basic, substrate stable, and depth up to 7e10 m (Good, 2004 and refer- ences; C. Clavijo pers. com., 2009). They are shallow infaunal filter feeders and fish must be present in the habitat for hosting their parasitic glochidia. In Mesozoic times they may have been depre- dated by lungfish. Taphonomical data (rather thin concentrationswith size sorting, dissarticulation, not fragmentation nor abrasion, random orienta- tion, presence of stable and instable positions), plus the sedimen- tological evidence of currents discussed above, indicate that the valve concentrations represent a death assemblage, deposited by currents of moderate energy not far fromwhere the bivalves lived, and in a relative short time spam after their death. The stressing conditions of this marginal lacustrine area would be also suggested by the total absence of fish remains in contrast to the records of the Puesto Almada Member in other localities as “Estancia El Torito”, “Puesto Limonao”, “Cañadón Los Chivos” and “Sierra de la Manea”, where the environmental conditions of the paleolake were adequate for the survival of an abundant fish fauna. These conditions include availability of nutrients, suitable pH, relatively constant water temperatures throughout the day and year and sufficient water depth in order to avoid extreme oscilla- tions of water temperature. In the Upper Jurassic Penglaizhen Formation (China), Li (2004) reported an association of the fushunograptid spinicaudatan Qinghaiestheria with the freshwater-brackish ostracods (darwin- uloids and Damonella). Li (2004) mentioned other occurrences of spinicaudatans (Euestheria, Neopolygrapta, and Dendrostracus) with fresh to brackish water taxa (freshwater gastropods Viviparus and Valvata, bivalve Unio, freshwater-brackish bivalve Neomiodon) in the Middle Jurassic Great Estuarine Group (Kildonnan Member, Lealt Shale Formation, Scotland), inhabiting lagoonal waters yielding relative palaeosalinities of 0e4&. All of the mentioned spinicaudatans share the presence of small punctae in their growth bands, which are useful for osmoregulationwhen the salinity of the water changes. This morphological feature allowed Li (2004) to propose that possible Qinghaiestheria and associated invertebrate could survive in freshwater-brackish environmental conditions. 6. Conclusions At “Estancia La Sin Rumbo” locality, 41 km north of the Cerro Cóndor village, a 45 m thick sequence of yellowish tuffs and tuffites of the Puesto Almada Member of the Cañadón Asfalto Formation crops out. Corresponding to the Megasequence II (mature hemi- graben) of Figari et al. (1992) and Figari (2005), it rests on the volcanic Lonco Trapial Formation of early Middle Jurassic age. The section shows a cyclic expansion-contraction of the lake basin. The expansion hemicycle is represented in the lower half of the section and includes eight episodes of contraction. The hemicycle of contraction includes episodes of expansion, which are more frequent in the upper part of the profile. Contraction is shown by the predominance of volcanic tuffs, deposited in the context of the silting of the Cerro Cóndor Depocenter. The tuffites of the upper part of the section contain several levels bearing spinicaudatans, ostracods, mollusks (bivalves) and larval stages of the first records of fossil Trichoptera cases in the Cañadón Asfalto Formation. The fossils mentioned lived in small bodies of water during the periods of expansion of the lake, when a major input of water to the basin was indicated by the presence of thin levels of fossiliferous tuffites. The dry climatic condition is indicated by the occurrence of great numbers of spinicaudatans preserved in levels with mud-cracks, suggesting several local mortality events, and also by the smallest size of carapaces of the spinicaudatan specimens. The fauna from “Estancia La Sin Rumbo” locality (spinicaudatan fushunograptid, ostracods, and caddishfly cases) adding the stressed warm and dry climatic situation probably could suggest that the conditions of the Puesto Almada Member lake are varying from fresh to brackish water. Also, freshwater conditions are indicated by the distributions of ostracods, reaching the two most abundant species: Penthesile- nula sarytirmenensis and Theriosynoecum barrancalensis minor, nearly 90% of the total of specimens. Taphonomic data of unionoid bivalves plus sedimentologic evidence of currents, indicate that the valve concentrations represent a death assemblage, deposited by currents of moderate energy not far fromwhere the bivalves lived, and in a relatively short time span after their death. The tapho- nomic evidence suggests that the caddisfly cases are autochtho- nous and that they lived in marginal environments of the lake system. The record of the spinicaudatan fushunograptid, adding others from the Puesto Almada Member (as Congestheriella rauhuti) and O.F. Gallego et al. / Journal of South American Earth Sciences 31 (2011) 54e6866 Author's personal copy a new U/Pb age (161 � 3 Ma) in zircons present in tuffites support a Late Jurassic age (Oxfordian to Tithonian) for this Member of the Cañadón Asfalto Formation. The caddisfly cases of the ichnogenera Conchindusia and Terrindusia are shared by two Middle-Upper Jurassic formations of Patagonia: the CañadónAsfalto Fm. and the La Matilde Fm. Both units also share other fossil invertebrates as the spinicaudatans (Fushunograptidae and Palaeolimnadiopseidae), bivalvemollusks (“Diplodon”, Corbiculidae andSphaeridae,Diplodon simplex and D. matildensis), gastropods, ostracods (Darwinulidae) and insect body fossils (Order Coleoptera and Hemiptera). The shared record of fossil invertebrates between the Cañadón Asfalto and theLaMatilde formations suggests notonlya coetaneous timeof deposition, but also similar environmental conditions. Acknowledgements This study was supported by the grants PIP 5760 and 5581 of CONICET. We acknowledge Dr. Jorge Genise (MEF-CONICET) for his help with the study of the trichopteran fossil cases, Drs. Shen Yanbin and Gan Li (Nanjing, China) for their helpful comments on the spinicaudatan taxonomy, and toMrs. Irene Ibarra andMr. Pedro Germán Fernández for allowing us fieldwork in the “Estancia La Sin Rumbo”. CNEA (Comisión Nacional de Energía Atómica) was helpful with logistic support at Campamento Los Adobes, Mr. Alejandro Hansen and Mrs. Ana María Flores for logistic support at Estancia Flores. Mr. Gabriel Giordanengo and Mr. Gustavo Barrios prepared the digital figures and Mr. Eduardo Llambias the thin sections. Thanks to Dr. P. Narváez and Dr. Tom DeVries and two anonymous reviewers of the journal for the critical reading of the manuscript. References Baldoni, A.M., 1990. Tafofloras del Jurásico medio de la Patagonia Extraandina. In: Volkheimer, W. (Ed.), Bioestratigrafía de los Sistemas Regionales del Jurásico y Cretácico de América del Sur. Comité Sudamericano del Jurásico y Cretácico, Mendoza 2, 313e353. Bocchino, A., 1967. Luisiella inexcutata gen. et sp. nov. (Pisces, Clupeiformes, Dus- sumieriidae) del Jurásico superior de la provincia del Chubut, Argentina. Ameghiniana 4, 91e100. Bordas, A.F.,1942. Peces del Cretácico del Río Chubut (Patagonia). Physis 19, 313e318. Cabaleri, N.G., Armella, C., 1999. Facies lacustres de la Formación Cañadón Asfalto (Caloviano-Oxfordiano), en la quebrada Las Chacritas, Cerro Cóndor, provincia del Chubut. Revista de la Asociación Geológica Argentina 54, 375e388. Cabaleri, N.G., Armella, C., 2005. Influence of a biohermal belt on the lacustrine sedimentation of the Cañadón Asfalto Formation (Upper Jurassic, Chubut province, southern Argentina). Geologica Acta 3, 205e214. Cabaleri, N.G., Armella, C., Silva Neto, D.G., 2005. Saline lakes of Cañadón Asfalto Formation (Middle-Upper Jurassic), Cerro Cóndor, Chubut province (Patagonia), Argentina. Facies 51, 350e364. Cabaleri, N.G., Armella, C., Silva Nieto, D., Volkheimer, W., 2006. Paleoambientes sedimentarios de la Formación Cañadón Asfalto (Jurásico Superior) en los depocentros de Cerro Cóndor y Gastre - Gan Gan Provincia del Chubut. 4� Congreso Latinoamericano de Sedimentología y 11� Reunión Argentina de Sedimentología. Resúmenes, San Carlos de Bariloche. 64. Cabaleri, N.G., Silva Nieto, D.G., Armella, C., Gallego, O.F., Cagnoni, M.C., Ramos, A.M., Panarello, H.O., 2008a. Estratigrafía de la Formación Cañadón Asfalto (Jurásico Superior) localidades tipo: río Chubut medio, Depocentro de Cerro Cóndor, Cuenca de Cañadón Asfalto, Patagonia, Republica Argentina. Actas XVII Con- greso Geológico Argentino, San Salvador de Jujuy. Resúmenes. 821e822. Cabaleri, N.G., Volkheimer, W., Armella, C., Gallego, O., Silva Nieto, D., Paez, M., Cagnoni, M., 2008b. Continental Aquatic Environments of the Jurassic in Extraandean Patagonia. XII Reunión Argentina de Sedimentología. Resúmenes, Buenos Aires. 47. Cabaleri, N.G., Volkheimer, W., Armella, C., Gallego, O., Monferrán, M., Cagnoni, M., Silva Nieto, D., Páez, M., 2010a. Humedales jurásicos y del J/K en la Cuenca Cañadón Asfalto, río Chubut medio, Argentina. 4� Simposio Argentino del Jurásico. Resúmenes, Bahía Blanca. 33. Cabaleri, N.G., Volkheimer, W., Armella, C., Gallego, O.F., Silva Nieto, D.G., Cagnoni, M.C., Ramos, A.M., Panarello, H.O., 2010b. Estratigrafía, análisis de facies y paleoambientes de la Formación Cañadón Asfalto: Jurásico, depocentro de Cerro Cóndor, río Chubut medio, Patagonia, Republica Argentina. Revista de la Asociación Geológica Argentina 66, 349e367. Cabaleri, N., Volkheimer, W., Silva Nieto, D., Armella, C., Cagnoni, M., Hauser, N., Matteini, M., Pimentel, M.M., 2010c. U-Pb ages in zircons from las Chacritas and Puesto Almada members of the Jurassic Cañadón Asfalto Formation, Chubut province, Argentina. VII South American Symposium on Isotope Geology, Brasilia. 190e193. Chen, P.J., 1999. Distribution and spread of the Jehol Biota. Palaeoworld 11, 1e6 (in Chinese with English abstract). Chen, P.J., Shen, Y.B., 1977. On the discovery of Afrograptidae (Conchostraca) in Zhejiang with its significance. Acta Palaeontologica Sinica 16, 81e94 (in Chinese with English abstract). Chen, P.J., Li, G., Batten, D.J., 2007. Evolution, migration and radiation of late Mesozoic conchostracans in East Asia. Geological Journal 142, 391e413. Codignotto, J., Nullo, F., Panza, J.L., Proserpio, C., 1979. Estratigrafía del Grupo Chubut entre Paso de Indios y Las Plumas, provincia del Chubut, Argentina. 7� Congreso Geológico Argentino, Neuquén. Actas 1, 471e480. Cortés, J.M., Baldoni, A., 1984. Plantas fósiles jurásicas del sur del Río Chubut medio. 9� Congreso Geológico Argentino, Buenos Aires. Actas 4, 432e443. Defretin-Lefranc, S., 1967. Étude sur les Phyllopodes du Bassin du Congo. Annales Musee Royal de L’Afrique Centrale Tervuren, Belgique. Serie Sciences Geo- logiques 56, 1e122. Do Carmo, D.A., Rafael, R.M.L., Vilhena, R.M., Tomassi, H.Z., 2004. Redescrição de Theriosynoecum silvai e Darwinula martinsi, Membro Crato (Formação Santana), Cretáceo Inferior, bacia do Araripe, NE Brasil. Revista Brasileira de Paleontologia 7, 151e158. Escapa, I.H., Sterli, J., Pol, D., Nicoli, L., 2008. Flora y tetrápodos del jurásico de la Formación Cañadón Asfalto en el área de Cerro Cóndor, provincia de Chubut. Revista de la Asociación Geológica Argentina 63, 613e624. Feruglio, E., 1949. Descripción geológica de la Patagonia. Dirección General de Yacimientos Petrolíferos Fiscales, Buenos Aires. 1, 1e334. Figari, E., 2005. Evolución tectónica de la cuenca de Cañadón Asfalto (zona del Valle Medio del Río Chubut). PhD Thesis, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, (Unpublished), 1e176. Figari, E.G., Courtade, S.F., 1993. Evolución tectosedimentaria de la Cuenca de Cañadón Asfalto, Chubut, Argentina. 12� Congreso Geológico Argentino y 2� Congreso de Exploración de Hidrocarburos, Buenos Aires. Actas 1, 66e77. Figari, E.G., García, D.G., 1992. Depósitos continentales en el Cerro Fortín. Análisis litofacial y arquitectónico de estos depósitos, aflorantes en la localidad citada, Chubut, Argentina. Boletín de Informaciones Petroleras 9, 2e8. Figari, E.G., Courtade, S.F., Homovc, J.F., 1992. Estructura de la Cuenca Cañadón Asfalto, provincia del Chubut. Yacimientos Petrolíferos Fiscales, Buenos Aires (Unpublished), 1e66. Figari, E.G., Courtade, S.F., Constantini, L.A., 1996. Stratigraphy and tectonis of Cañadón Asfalto basin, lows of Gastre and Gan Gan, north of Chubut province, Argentina. In: Riccardi, A.C. (Ed.), Advances in Jurassic Research, 1-2. Transtec Publications, Zurich, pp. 359e368. Flores, M.A., 1948. Investigaciones geológicas en el río Chubut medio, entre los cerros Cóndor y Pavada (Territorio Nacional del Chubut). Yacimientos Petrolí- feros Fiscales, Buenos Aires (Unpublished), 1e72. Frenguelli, J., 1949. Los estratos con “Estheria” en el Chubut (Patagonia). Revista de la Asociación Geológica Argentina 4, 11e24. Gallego, O.F., 1994. Conchóstracos Jurásicos de Santa Cruz y Chubut, Argentina. Ameghiniana 31, 333e345. Gallego, O.F., 1999. Estudio Sistemático de las Faunas de Conchostracos Triásicos de la República Argentina, PhD thesis, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, (Unpublished), 1e210. Gallego, O.F., Cabaleri, N., 2005. Conchóstracos de la Formación Cañadón Asfalto (Jurásico Medio e Superior): analisis preliminar de su distribución estrati- gráfica. Ameghiniana 42 ((supl.) 51R. Gallego, O.F., Covacevich, V., 1998. Conchostracos Triásicos de las Regiones de Anto- fagasta, Atacama y Coquimbo, Chile. Revista Geológica de Chile 25, 115e137. Gallego, O.F., Martins Neto, R.G., 2006. The Brazilian Mesozoic conchostracan faunas: its geological history as an alternative tool for stratigraphic correlations. Geociências 25, 231e239. Gallego, O.F., Martins Neto, R.G., Nielsen, S., 2005. Conchostracans and insects from the Upper Triassic of the Biobío river (“Santa Juana formation”) from Chile. Revista Geológica de Chile 31, 293e311. Gallego, O.F., Shen, Y.B., Cabaleri, N.G., Hernández, M., 2010. The genus Con- gestheriella Kobayashi, 1954 (Conchostraca, Afrograptioidea): redescription and new combination to Isaura olsoni Bock from Venezuela and a new species from Argentina (Upper Jurassic). Alavesia 3, 11e24. Genise, J.F., Gallego, O.F., Melchor, R.N., de Valais, S., 2002. Capullos fósiles de tri- cópteros (Conchindusia isp.) (Insecta) construidos con valvas de conchóstracos del Jurásico de la Patagonia, Argentina. VIII Congreso Argentino de Paleon- tología y Bioestratigrafía. Resúmenes, Corrientes. 93. Good, S.C., 1989. Nonmarine Mollusca in the Upper Triassic Chinle Formation and related strata of the western Interior: systematics and distribution. In: Lucas, S.G., Hunt, A.P. (Eds.), Dawn of the Age of Dinosaurs in the American Southwest. New Mexico, Museum of Natural History, pp. 233e247. Good, S.C., 2004. Paleoenvironmental and paleoclimatic significance of freshwater bivalves in the Upper Jurassic Morrison Formation, western Interior, USA. Sedimentary Geology 167, 163e176. Govindan, A., 1975. Jurassic freshwater ostracods from the Kota limestone of India. Palaeontology 18, 207e216. Graf, D.L., 2001. A phylogenetic perspective on the evolution of the Unionoida (Mol- lusca Bivalvia Palaeoheterodonta): using pattern to test hypotheses of macroevo- lutionary process. Ph.D. Dissertation, University of Michigan, Biology Department. Grimaldi, D., Engel, M.S., 2005. Evolution of Insects. Cambridge University Press, New York. O.F. Gallego et al. / Journal of South American Earth Sciences 31 (2011) 54e68 67 Author's personal copy Homovc, J.F., Figari, E.G., Courtade, S.F.,1991. Geología de la CuencadeCañadónAsfalto. Provincia del Chubut. Yacimientos Petrolíferos Fiscales, Buenos Aires. 1e27. Ivanov, V.D., Sukatsheva, I.D., 2007. Order Trichoptera. In: Rasnitsyn, A.P., Quicke, D.L.J. (Eds.), History of Insects. Springer, The Netherlands, pp. 199e220. Jarzembowski, E.A., 1995. Fossil caddisflies (Insecta: Trichoptera) from the early Cretaceous of southern England. Cretaceous Research 16, 695e703. López-Arbarello, A., 2004. The record of Mesozoic fishes from Gondwana (excluding India and Madagascar). In: Arriata, G., Tintori, A. (Eds.), Mesozoic Fishes 3. Systematics, Paleoenvironments and Biodiversity. Vrelag Dr. Friedrich Pfgeil, Munich, pp. 549e624. López-Arbarello, A., Arratia, G., Codorniú, L., 2002. Coccolepids from South America and the early history of Chondrostei. Journal of Vertebrate Paleontology 22, 80Ae81A. Laprida, C., Díaz, A., Ratto, N., 2006. Ostracods (Crustacean) from thermal waters, southern Altiplano, Argentina. Micropaleontology 52, 177e188. Lesta, P., Ferello, R., 1972. Región extraandina de Chubut y norte de Santa Cruz. In: Leanza, A. (Ed.), Geología Regional Argentina. Academia Nacional Ciencias Córdoba, Córdoba, pp. 601e653. Li, Z.W., 1985. Middle Jurassic ostracods from the Longjiagou Formation of Gahai, Gansu. Acta Micropaleontologica Sinica 2, 257. Li, G., 2004. Discovery of Qinghaiestheria from the Upper Jurassic Penglaizhen Formation in Sichuan, southwestern China. Journal of Asia Earth Sciences 24, 361e365. Li, G., Shen, Y.B., Batten, D.J., 2007. Yanjiestheria, Yanshania and development of the Eosestheria conchostracan fauna of the Jehol biota in China. Cretaceous Research 28, 225e234. Ljubimova, P.S., 1955. Ostracodes of the Mesozoic deposits in the Volga-Ural region. Trudy Instituta Geologicheskikh Nauk, Akademiya Nauk Ukraynskoy, USSR. VNIGRI (Russian Petroleum research Institute of Geological Prospecting) (New Series), 84, 3e189. [In Russian]. Mandelstam, N.I., 1947. Ostracods of the Middle Jurassic deposits of the Man- gishlaka peninsula. (eastern side of the Caspian). In: Trudy Instituta Geo- logicheskikh Nauk, Akademiya Nauk Ukraynskoy, USSR (Ed.), Mikrofauna, Petroleum occurrence, Caucasus, Emba and central Asia. VNIGRI (Russian Pet. Res. Inst. Geol. Prospecting), Leningrad-Moscow 239e259. [In Russian]. Martínez, S., Figueiras, A.J., Da Silva, S., 1993. A new unionoid (Mollusca, Bivalvia) from the Tacuarembó Formation (Upper Triassic- upper Jurassic), Uruguay. Journal of Paleontology 67, 962e965. Martínez, S., Gallego, O.F., Cabaleri, N., 2007. Nueva fauna de moluscos de la For- mación Cañadón Asfalto (Jurásico Medio a Superior) Chubut, Argentina. Ame- ghiniana 44 (supl.) 96R. Martens, K., Rossetti, G., Horne, D.J., 2002. How ancient are ancient asexuals? Proceedings Royal Society London B. 270, 723e729. Monferran, M.D., Genise, J.F., Gallego, O.F., 2008. Capullos fósiles de Tricópteros del Jurásico Medio a Superior de la Patagonia Argentina. VII Congreso Argentino de Entomología, Huerta Grande. Resúmenes, Córdoba. 230. Monferran, M.D., Gallego, O.F., Genise, J.F., 2009. Nuevos datos sobre los capullos fósiles (Trichoptera) del Jurásico de la Patagonia Argentina. Comunicaciones Científicas y Tecnológicas. Universidad Nacional del Nordeste. http://www. unne.edu.ar. Morton, L.S., Herbst, R., 2001. Nuevas especies del género Diplodon Spix (Bivalvia, Unionidea) del Jurásico Medio (Formación La Matilde), provincia de Santa Cruz, Argentina. Revista del Museo Argentino de Ciencias Naturales 3, 159e164. Musacchio, E.A., 1989. Biostratigraphy of the Non-marine Cretaceous of Argentina based on Calcareous Microfossils. In: Wiedmann, J. (Ed.), Cretaceous of the western Tethys. Third Internacional Cretaceous Symposium, Tübingen , 1987, Proceedings, 811e851. Musacchio, E.A., 1995. Estratigrafía y micropalentología del Jurásico y el Cretácico en la comarca del Valle Medio del Río Chubut, Argentina. 6� Congreso Argentino de Paleontología y Bioestratigrafía, Trelew. Actas, 179e187. Musacchio, E.A., 2001. Relaciones paleobiogeográficas de los ostrácodos no marinos del Jurásicoyel CretácicodePatagonia. ActaGeologica Leopoldensia 24, 293e310. Musacchio, E.A., Beros, C., Pujana, E.I., 1990. Microfósiles continentales del Jurásico y Cretácico del Chubut y su contribución a la bioestratigrafía de la Cuenca del Golfo de San Jorge. Argentina. In: Volkheimer, W. (Ed.), Bioestratigrafía de los Sistemas Regionales del Jurásico y Cretácico de América del Sur. Comité Sudamericano del Jurásico y Cretácico, Mendoza 2, 355e383. Nullo, F., 1983. Descripción geológica de la Hoja 45c, Pampa de Agnia, provincia del Chubut. Servicio Geológico Nacional, Boletín, Buenos Aires. 199, 1e94. Ortmann, A.E., 1920. Correlation of shape and station in freshwater mussels (Naiades). Proceedings of the American Philosophical Society 59, 269e312. Parodiz, J.J., Bonetto, A.A., 1963. Taxonomy and zoogeographic relationships of the south American Naiades (Pelecypoda: Unionacea and Mutelacea). Malacologia 1, 179e213. Perea, D., Soto, M., Veroslavsky, G., Martínez, S., Ubilla, M., 2009. A late Jurassic fossil assemblage in Gondwana: biostratigraphy and correlations of the Tacuarembó Formation, Parana basin, Uruguay. Journal of South American Earth Sciences 28, 168e179. Piatnitzky, A., 1933. Informe preliminar sobre reconocimientos geológicos en la región del Río Chubut. Yacimientos Petrolíferos Fiscales, Buenos Aires (Unpublished), 1e36. Piatnitzky, C., 1936. Informe preliminar sobre el estudio geológico de la región situada al norte de los lagos Colhué Huapi y Musters. Yacimientos Petrolíferos Fiscales, Buenos Aires (Unpublished), 1e120. Pinto, R.L., Rocha, C.E.F., Martens, K., 2004. On the genus Penthesilenula Rossetti and Martens, 1998 (Crustacea, Ostracoda, Darwinulidae) from (semi-) terrestrial habitats in São Paulo State (Brazil), with the description of a new species. Journal of Natural History 38, 2567e2589. Platt, N., Wright, V., 1991. Lacustrine carbonates: facies models, facies distributions and hydrocarbon aspects. In: Anadon, P., Cabrera, Ll., Kelts, K. (Eds.), Lacustrine Facies Analysis. Special Publications International Association of Sedimentology 13, 57e74. Proserpio, C.A., 1987. Descripción geológica de la Hoja 44 e, Valle General Racedo. Dirección Nacional de Minería y Geología, Boletín 201, Buenos Aires. 1e102. Rauhut, O.W.M., 2006. A brachiosaurid sauropod from the late Jurassic Cañadón Calcáreo Formation of Chubut, Argentina. Fossil Record 9, 226e237. Rossetti, G., Martens, K., 1998. Taxonomic revision of the Recent and Holocene representatives of the Family Darwinulidae (Crustacea, Ostracoda), with a description of three new genera. Bulletin de l’Institut Royal des Sciences Naturelles de Belgique. Biologie 65, 55e110. Rossetti, G., Martens, K., Mourguiart, P., 1996. On Darwinula incae Delachaux, 1928. A Stereo Atlas of Ostracod Shells 23, 57e66. Shen, Y.B., Chen, P.J., 1982. Jurassic and Cretaceous conchostracans from Sichuan- Basin. In: Continental Mesozoic Stratigraphy and Palaeontology in Sichuan basin of China, Part II, Paleontological Professional Papers. People’s publishing House of Sichuan, Chengdu (In Chinese with English abstract). 392e415. Shen, Y.B., Gallego, O.F., Martínez, S., 2004. The conchostracan subgenus Orthes- theria (Migransia) from the Tacuarembó Formation (Late Jurassic e ?Early Cretaceous, Uruguay), with notes on its geological age. Journal of South American Earth Sciences 16, 631e638. Silva Nieto, D.G., 2005. Hoja Geológica 4369-III, Paso de Indios. Escala 1:250.000. Boletín del Instituto de Geología y Recursos Minerales. Servicio Geológico Minero Argentino 265, 1e72. Silva Nieto, D.G., Cabaleri, N.G., Salani, F.M., 2003. Estratigrafía de la Formación Caña- dón Asfalto (Jurásico Superior) provincia del Chubut. Ameghiniana 40 (supl.) 46R. Silva Nieto, D., Cabaleri, N., Salani, F., Coluccia, A., 2002a. Cañadón Asfalto, una cuenca de tipo “Pull Apart” en el área de Cerro Cóndor, Provincia del Chubut. 15� Congreso Geológico Argentino, Calafate. Actas, 238e243. Silva Nieto, D., Cabaleri, N., Salani, F., Márquez, M., González Díaz, E., Coluccia, A., 2002b. Hoja Geológica 4369-27 Cerro Cóndor, Provincia del Chubut. Escala 1:100.000. Boletín del Instituto de Geología y Recursos Minerales. Servicio Geológico Minero Argentino 328, 1e68. Silva Nieto, D., Cabaleri, N., Armella, C., Volkheimer, W., Gallego, O., 2007. Hipótesis sobre la evolución tecto-sedimentaria de la Formación Cañadón Asfalto, Pro- vincia del Chubut. Ameghiniana 44 (supl.) 67R. Stipanicic, P.N., Bonetti, M., 1969. Posiciones estratigráficas y edad de las principales floras jurásicas argentinas. II) Floras doggerianas y málmicas. Ameghiniana 7, 101e118. Stipanicic, P.N., Rodrigo, F., Baulíes, O., Martínez, C., 1968. Las formaciones pre- senonianas en el denominado Macizo Nordpatagónico y regiones adyacentes. Revista de la Asociación Geológica Argentina 23, 67e98. Sukatsheva, I.D., 1998. The lower Cretaceous caddisfly (Trichoptera) case assem- blages. Proceedings of the First International Palaeoentomologial Conference, Moscow. 163e165. Tasch, P., 1987. Fossil Conchostraca of the southern Hemisphere and continental Drift. Paleontology, biostratigraphy and dispersal. Geological Society of America Memoir 165, 1e290. Tasch, P., Volkheimer, W., 1970. Jurassic Conchostracans from Patagonia. The University of Kansas Paleontological Contributions 50, 1e23. Tiercelin, J.J., 1991. Natural resources in the lacustrine facies of the Cenozoic rift basins of East Africa. In: Anadón, P., Cabrera, Ll., Kelts, K. (Eds.), Lacustrine Facies Analysis. Special Publications International Association of Sedimentology, Oxford, United Kingdom 13, 3e37. Vallatti, P., 1986. Conchostracos jurásicos de la Provincia del Chubut, Argentina. 4� Congreso Argentino de Paleontología y Bioestratigrafía, Mendoza. Actas 4, 29e38. Volkheimer, W., Quattrocchio, M., Cabaleri, N.G., García, V., 2008. Palynology and paleoenvironment of the Jurassic lacustrine Cañadón Asfalto Formation at Cañadón Lahuincó locality, Chubut province, central Patagonia, Argentina. Revista Española de Micropaleontología 40, 77e96. Volkheimer, W., Gallego, O.F., Cabaleri, N.G., Armella, C., Narvaez, P., Silva Nieto, D.G., Paez, M.A., 2009. Stratigraphy, palynology, and conchostracans of a Lower Cretaceous sequence at the Cañadón Calcáreo locality, Extra-Andean central Patagonia: age and palaeoenvironmental significance. Cretaceous Research 30, 280e282. Wang, S.E., 1983. Some Jurassic-Cretaceous conchostracans from Qinghai. Acta Palaeontologica Sinica 22, 460e467. Whatley, R., 1983. The Application of Ostracoda to Palaeoenvironmental Analysis. In: Maddocks, R.F. (Ed.), Applications of Ostracoda. University Houston Geo- sciences, Houston, pp. 51e77. Whatley, R., 1988. Population Structure of Ostracods: Some General Principles for the Recognition of Palaeoenvironments. In: De Deckker, P., Colin, J.P., Peypouquet, J.P. (Eds.), Ostracoda in the Earth Sciences. Elsevier, The Netherlands, pp. 245e256. Zhang, G., Buatois, L.A., Mángano, M.G., Aceñolaza, F.G., 1998. Sedimentary facies and environmental ichnology of a Permian playa-lake complex in western Argentina. Palaeogeography, Palaeoclimatology, Palaeoecology 138, 221e243. Zheng, S.Y., 1995. Nonmarine Triassic and Jurassic ostracods from Tarim Basin. Acta Palaeontologica Sinica 34, 729e730. O.F. Gallego et al. / Journal of South American Earth Sciences 31 (2011) 54e6868