The southernmost record of a Neuryurini Hoffstetter, 1958 (Mammalia,Xenarthra, Glyptodontidae)

In this contribution we document the southernmost and probably the oldest record of the tribe Neuryurini (Glyptodontidae). The southernmost record of this tribe outside of Patagonia is Neuryurus sp. from Lujanian sediments (Luján Formation, late Pleistocene–early Holocene) at Quequén Grande River (Buenos Aires Province, Argentina). The first and only previous record of a specimen of the Neuryurini in Patagonia was reported from the upper levels of the Puerto Madryn Formation (Huayquerian SALMA, late Miocene), exposed in Península Valdés (Chubut Province, Argentina). The new specimen described here and assigned to an indeterminate Neuryurini was recovered at Estancia La Peninsular (Santa Cruz Province, Argentina). This locality has been recognized in geological studies as part of the Santa Cruz Formation (Santacrucian SALMA, late early Miocene), but there have been no fossils described from this site until now. Therefore, the new specimen represents, with the two confirmed records of Glyptodon Owen and Panochthus Burmeister (both from the Quaternary), the only non-Propalaehoplophorinae glyptodontids reported for Santa Cruz Province.     

Decapod Crustacea from the Agrio Formation (Lower Cretaceous) of the Neuquén Basin,Argentina

Abstract: Two species of decapod crustacean are recorded from the Agua de la Mula Member of the Agrio Formation (Upper Hauterivian – Lower Barremian) of the Neuquén Basin of west‐central Argentina, namely Astacodes falcifer Bell and a new species of Palaeohomarus, P. pacificus. The preservation of the specimens is exceptional, some showing delicate compound eyes and a stridulatory apparatus, features rarely found in fossil forms. Many specimens are preserved articulated inside calcareous nodules, within dark‐grey shales. The lobster‐bearing sediments accumulated in a low‐energy marine environment and diagenetic mineralization occurred very rapidly, prior to significant decay, thus allowing exceptional preservation of specimens. Palaeohomarus was a rare genus in the Cretaceous with a palaeogeographic distribution restricted to the Mediterranean Tethys, the eastern USA and Madagascar, while Astacodes falcifer has been recorded only from Speeton (eastern England) and Neuquén.     

Late Jurassic ichthyosaurs from the Neuquén Basin,Argentina

Late Jurassic ichthyosaurs are well represented in the Tithonian of the Neuquén Basin, in northwestern Patagonia, Argentina. Most of the ichthyosaur material from the Neuquén Basin was originally identified as Ophthalmosaurus. Recently, the new ichthyosaur genus Caypullisaurus was described, based on an almost complete mature specimen from Cerro Lotena. Some material previously referred to Ophlhalmosaurus has been referred to the new genus. However, both genera are present in the Tithonian of the Neuquén Basin. The discovery of an articulated forefin in Cajón de Almanza (near Loncopue, Neuquén) confirms the presence of Ophthalmosaurus in the uppermost Tithonian of the Neuquén Basin.     

Taxonomic and biostratigraphic re-evaluation ofPerisphinctes internispinosus Krantz, 1926 (Upper Jurassic, Ammonoidea)

The lectotype ofPerisphinctes internispinosus Krantz, 1926, type species ofWindhauseniceras Leanza, 1945, from the upper Middle Tithonian of Cerro Lotena (Neuquén-Mendoza Basin, Argentina) is designated. The type series, housed in the Paläontologisches Institut der Universität Bonn, was originally illustrated by hand-drawings of two of the eleven specimens. The lectotype is illustrated by a photograph for the first time. The specimen is probably a large microconch; the most likely corresponding macroconch appears to beH. aff.steinmanni (Steuer, 1897) from Cerro Lotena.Windhauseniceras internispinosum is the index and guide species of theInternispinosum Biozone, upper Middle Tithonian, most probablyPonti Zone in age. The occurrence in Arroyo del Yeso (Mendoza) below a succession ofMicracanthoceras species includingM. mirum (Leanza, 1945) which is very close toM. microcanthum, strongly supports this correlation. The species occurs throughout the Neuquén-Mendoza Basin and probably also in the Tarapacá Basin, Northern Chile.     

A New Species of Ctenomys (Rodentia: Ctenomyidae) from Patagonia Related to C. sociabilis

The genus Ctenomys includes a high number of taxa, with at least ten species from Patagonia and three recently described species for northeastern Chubut Province (Argentina). Ctenomys sociabilis is a social species of the genus Ctenomys and is currently distributed in the surrounding area of Sierra Cuyin Manzano (Neuquén Province), with a recently extinct population that occurred in Laguna Nahuelquir (Cushamen, Chubut Province). Molecular analyses have placed C. sociabilis at the base of Ctenomys clade, as the sister species to all other Ctenomys. Based on a morphological assessment (qualitative and quantitative) and DNA sequencing, we describe a new species of Ctenomys from Esquel, Chubut Province. Phylogenetic analysis shows the new species to be closely related to C. sociabilis, with evidence of solitary behavior. This new species is the first reported to be closely related phylogenetically to Ctenomys sociabilis at the base of the Ctenomys phylogeny. We provide anatomical comparisons between the new species and other species of Ctenomys from Patagonia, especially C. sociabilis.

     

Valanginian and Hauterivian marine ostracods from Patagonia (Argentina): Correlations and palaeogeography

Some Early Cretaceous ostracod assemblages from the Neuquén Basin (West Central Argentina) share taxa with roughly coeval faunas previously reported from South Africa. Five assemblages are dealt with, from which two are proposed as formal biostratigraphic zones. The age of the assemblages is gauged in the frame of the global time scale taking into account previous information from nannofossil and ammonite studies. Otherwise, the Hauterivian ostracods from the Fontana Lake area (Andes Patagónicos) show noticeable differences regarding the Neuquén assemblages, both at the specific and the generic taxonomical composition. These differences seem of interest to ponder the relevance of the mentioned similarities between West Central Argentina and South Africa. The hypothesis of (Reyment, R.A., Tait, E.A., 1972. Biostratigraphical dating of the early history of South Atlantic Ocean. Philosophical Transactions of the Royal Society of London B 164, 5–95.), suggesting free faunal interchange between the last mentioned regions, is discussed in the framework of the diachronic evolution of the sea-floor expansion of the South Atlantic and their structural consequences.     

New record of anoplocephalid eggs (Cestoda: Anoplocephalidae) collected from rodent coprolites from archaeological and paleontological sites of Patagonia,Argentina

Results of paleoparasitological examination of rodent coprolites collected from archaeological and paleontological sites from Patagonia, Argentina, are present. Each coprolite was processed, rehydrated, homogenized, spontaneously sedimented and examined using light microscope. Coprolites and eggs were described, measured and photographed, and were compared with current faeces of Lagidium viscacia. Eggs with morphological features, attributed to an anoplocephalid cestode were found in samples collected from Cueva Huenul 1 (36°56′45″S, 69°47′32″W, Neuquén Province, Holocene) and Los Altares Profile (43º53′35″S, 68º23′21″W, Chubut Province, Late Holocene). These are the first findings of this anoplocephalid from faecal material from patagonic rodents.     

Nutritional and ecotoxicological aspects of the acidotolerant alga Keratococcus rhaphidioides (Chlorophyta): a potential candidate for algal mediated bioremediation of extremely acidic waters

Journal of Applied Phycology - The green alga Keratococcus rhaphidioides was isolated in axenic culture from water samples of the extremely acid Lake Caviahue (Neuquén, Argentina). The lake pH...     

An exceptional storm accumulation of nautilids in the Lower Cretaceous of the Neuquén Basin,Argentina

Cichowolski, M., Pazos, P.J., Tunik, M.A. & Aguirre‐Urreta, M.B. 2011: An exceptional storm accumulation of nautilids in the Lower Cretaceous of the Neuquén Basin, Argentina. Lethaia, Vol. 45, pp. 121–138. An exceptional accumulation of nautilid shells of the species Cymatoceras perstriatum (Steuer) is reported and described in the Lower Cretaceous Agrio Formation of the Neuquén Basin (west‐central Argentina). The bed represents a storm deposit in a shallow‐water environment within the mid‐ramp. The evidences of a storm‐related origin of the bed come from the petrographic analysis and taphonomic features of the shells, specially the sedimentary infill pattern. The shells are dispersed in patches within the stratum, without any orientation relative to the bedding plane. It is proposed that the shells were floating after the death of the animals, although most of them have an almost complete living chamber. The presence of some heavily encrusted shells suggests that there is a mixing of specimens with different drift times. A variety of factors related to the origin of such high number of nautilid shells are discussed, including a transgressive stand system tract, the possible existence of a gregarious behaviour, changes in salinity and wind directions. □Lower Cretaceous, Nautilids, Neuquén Basin, shell accumulation, storm deposit.     

Taphonomy and palaeoecology of Hauterivian–Barremian nerineoid shell beds from the Neuquén Basin,west‐central Argentina

Nerineoid shell beds are described for the first time from Lower Cretaceous deposits of southern South America. These come from carbonates near the top of the Agrio Formation in southern Mendoza Province, west‐central Argentina. To envisage the origin of the nerineoid shell beds, a taphonomic study was carried out, which indicated that these represent within‐habitat time‐averaged, primary sedimentological concentrations with a secondary biogenic imprint related to a relatively high local production of nerineoid shells. The associated palaeoenvironments were studied through a facies analysis of the carbonate succession including the shell beds. The carbonates were deposited in a homoclinal ramp system and depict a shallowing upward trend from mid to inner ramp. The individuals lived and accumulated in oolitic shoals within the inner ramp, in a shallow, well‐lit, high‐energy setting above fair‐weather wave base. Substrate was oxygenated and loose. The nerineoids are shown to belong to one species of the genus Eunerinea, and through the functional morphology of the shells they are tentatively interpreted as infaunal or semi‐infaunal. It is suggested that the recorded monospecific nerineoid shell beds indicate that the palaeoenvironmental conditions may have been favourable for the development of abundant populations of these gastropods in the northern part of the Neuquén Basin during a short time interval in the Hauterivian–Barremian boundary. This could have been related to a brief warming episode, but other factors may have also been involved. □Argentina, Early Cretaceous, Gastropods, nerineoids, Neuquén Basin, shell beds, taphonomy.     

Brote de histoplasmosis en la provincia de Neuquén,Patagonia Argentina

BackgroundIn Argentina, there are no reports of autochthonous cases of histoplasmosis in the southern regions of the country.AimTo report a histoplasmosis outbreak in Zapala town, Province of Neuquén, Patagonia Argentina.MethodsWe evaluated the clinical and epidemiological characteristics of 5 patients involved in the outbreak. Environmental studies were conducted to determine the source of infection. The genetic profile of Histoplasma capsulatum strains isolated from the index case (IC) were compared with clinical isolates from Argentinean patients not related to the outbreak, using RAPD-PCR with primers 1281-1283.ResultsThe patients were residents of Zapala, and had not visited other geographical areas before. All patients had an influenza-like syndrome, and X-ray revealed disseminated micronodular images throughout the lung parenchyma. The IC needed specific antifungal therapy; the remaining 4 patients had mild symptoms, and did not require therapy. All of them had a good clinical outcome. Strains of H. capsulatum isolated from blood culture and lung biopsy of the IC showed a genetic profile different from other strains analyzed. The presence of the fungus in the environment was demonstrated by the detection of anti-Histoplasma antibodies in BALB/c mice inoculated with soil obtained in a culvert where workers had dug up earth after a landslide.ConclusionsThis outbreak suggests the histoplasmosis endemic area is under the 38° S parallel. Patients from Neuquén, Patagonia Argentina, with compatible symptoms of histoplasmosis should be tested, regardless of their travel or exposure history.     

Morphological trends and environment: a case study on Early Cretaceous Myophorelloidea (Bivalvia,Trigoniida) from Neuquén Basin,Argentina

Trigoniide clams were conspicuous components of bivalve faunas in shallow seas during most of the Mesozoic. Morphological trends in different features of shell shape and ornamentation of three related species of myophorelloids from the Agrio Formation (Early Cretaceous of Neuquén Basin, Argentina) that inhabited environments of different hydrodynamic energy conditions are explored in this study by means of a detailed morphometric analysis. Four hydrodynamic energy categories were established for depositional environments, from most (1), to least (4), energetic. General shell shape was characterized by measurements of height, length and width. New quantitative methods were developed to evaluate the distribution of costae along the marginal carina and the divergence of costae along the flank. Morphometric variables were detrended with respect to size, to avoid ontogenetic variability in further analyses. Relative width of the shell increases as environments become higher in hydrodynamic energy; this unusual trend may be interpreted as an anchoring/stabilizing strategy developed by the lineage in shallow marine environments. Trends in ornamentation correspond to more densely distributed costae in environments of higher hydrodynamic energy, a pattern that improves substrate penetration.     

Distributional patterns of the species of <Emphasis Type="Italic">Valeriana</Emphasis> (Valerianaceae) in southern South America

Distributional patterns of Valeriana species from southern South America were analyzed. We prepared a database with the records of 40 species from Argentina and Chile south of 33°S, obtained from herbarium specimens, published taxonomic studies and field trips. We undertook a track analysis and a parsimony analysis of endemicity (PAE), the latter with 134 grid cells of 1.5° latitude by 1.5° longitude. Three generalized tracks and one node were obtained, and three areas of endemism were identified. These general patterns of distribution in Valeriana were used to infer possible vicariance and dispersal events that might have shaped them. We identified a center of diversification in Central Chile and the Argentinean province of Neuquén. It represents a complex area that is related to both the Central Chilean and Subantarctic subregions.     

The occurrence of Cavia tschudi (Rodentia,Caviidae) in the Southwest of Salta Province,Argentina

The first record of Cavia tschudi Fitzinger, 1857 for the subandean area of Salta Province, Argentina, is herein presented.

This species presently inhabits the subandean area of the provinces of Tucumán and Jujuy. The materials are composed of two mandibles coming from an archaeological site, which had been occupied ca. 1480 AD, at 2300 m a.s.l.     

Studies on uroporphyrinogen decarboxylase from Chlorella kessleri (Trebouxiophyceae, Chlorophyta)

Uroporphyrinogen decarboxylase (UroD) (EC 4.1.1.37) is an enzyme from the tetrapyrrole biosynthetic pathway, in which chlorophyll is the main final product in algae. This is the first time that a study on UroD activity has been performed in a green alga (Chlorella). We isolated and partially purified the enzyme from a Chlorella kessleri (Trebouxiophyceae, Chlorophyta) strain (Copahue, Neuquén, Argentina), and describe for the first time some of its properties. In C. kessleri, the decarboxylation of uroporphyrinogen III occurs in two stages, via 7 COOH and then 6 and 5 COOH intermediates, with the decarboxylation of the 7 COOH compound being the rate-limiting step for the reaction. Cultures in the exponential growth phase showed the highest specific activity values. The most suitable conditions to measure UroD activity in C. kessleri were as follows: 0.23-0.3 mg protein/mL, approximately 6-8 micromol/L uroporphyrinogen III, and 20 min incubation time. Gel filtration chromatography and Western blot assays indicated that UroD from C. kessleri is a dimer of approximately 90 kDa formed by species of lower molecular mass, which conserves enzymatic activity.     

Two new Neotropical species of Perithreticus Vaillant 1973 (Diptera: Psychodidae,Psychodinae)

The genus Perithreticus is recorded for the first time from Central America and the Caribbean. Two new species are described and figured: P. arboscandens Kvifte & Andersen, n. sp. from Zurquí, San José Province, Costa Rica and P. guantanamera Kvifte & Andersen, n. sp. from Alexander von Humboldt National Park, Guantánamo Province, Cuba. The generic diagnosis is emended to accommodate the newly described species, and a key to the males of the Perithreticus species of the world is presented.     

Encrusting patterns and life habit of Mesozoic trigonioids: a case study of Steinmanella quintucoensis (Weaver) from the Early Cretaceous of Argentina

Luci, L. 2010: Encrusting patterns and life habit of Mesozoic trigonioids: a case study of Steinmanella quintucoensis (Weaver) from the Early Cretaceous of Argentina. Lethaia, 10.1111/j.1502‐3931.2009.00210.x. Trigonioid bivalves of the genus Steinmanella Crickmay are abundant at the top of the Vaca Muerta Formation, Neuquén Basin of Argentina, of Early Valanginian age. The species Steinmanella quintucoensis (Weaver) is frequently encrusted by oysters, serpulids and mytilids. Oysters are the most conspicuous encruster, followed by serpulids and then mytilids. A taphonomic, palaeoecological and taxonomic analysis was performed on the encrusting fauna of S. quintucoensis. An analysis of encrusting preference was performed on the basis of differences in ornamentation of the host shell, which was divided in a strongly tubercled flank and a smoother ribbed corselet and escutcheon zone. A higher encrustation frequency was found for the corselet and escutcheon zone, over the larger flank. Possible explanations are differences in the sculpture of each part of the valve, closeness to the respiratory openings of the host, and relation to life position of the trigonioids. In this respect, a palaeoecological analysis of the life position of the genus Steinmanella was made on the basis of functional morphology, encrustation patterns and comparison with related fossil forms as well as living representatives, finding that the most suitable position to explain encrustation patterns and functional morphology is one with the flanks below the water–sediment interface, and the corselets exposed above the substrate. □Early Cretaceous, encrustation, Neuquén Basin, trigonioids.     

Pupal and larval-pupal parasitoids (Hymenoptera) obtained fromAnastrepha Spp. andCeratitis capitata (Dipt.: tephritidae) pupae collected in four localities of Tucuman province,Argentina

Pupal and larval-pupal parasitoids were obtained from 5 % of the 1,413 tephritid puparia collected in four localities of the Tucumán province, Argentina, from April, 1991 to April, 1993.Ceratitis capitata (Wiedemann) was attacked byPachycrepoideus vindemmiae (Rondani) (Pteromalidae), a pupal parasitoid, andAganaspis pelleranoi (Brèthes) (Eucoilidae), a larval parasitoid.Anastrepha spp. were attacked byDoryctobracon areolatus (Szépligeti) (Braconidae), a larval parasitoid, and also byA. pelleranoi. Information about parasitism, percentage of emergence of tephritid species and pupal viability in different localities is provided.     

Contribution to the Knowledge of the Pre-imaginal Stages of Neotropical Hydrobiosidae (Trichoptera): Metachorema griseum Schmid

Mature larvae and pupae of Metachorema griseum Schmid are described for the first time. The known distribution of the genus includes the province of Neuquén in Argentina and central and southern Chile. The distinctive characters of the larvae of this genus are: (1) prothoracic sternite consisting of a wide subrectangular central sclerite and a pair of elongated lateral sclerites, (2) anterior femora with a narrow basodistal process, (3) anterior tibia and tarsus fused and (4) anal prolegs with a short lateral sclerite with basal spine and claws simple with ventral spine and two ventral setae.