Northeastern Buenos Aires Province Research Articles

New bivalve burrows from the mid-Holocene of northeastern Buenos Aires Province (Argentina): ichnotaxonomy and ethology

Oblongichnus vulpesi n. isp. is herein described as amygdaloid, oval or cleft-shaped burrows with a lining of variable thickness and an oblong to quadrangular elongated shaft from the mid-Holocene of the Destacamento Río Salado Member. Valves of the solenid bivalve species Solen tehuelchus were found within the burrows, indicating that this razor clam is the tracemaker. This new finding corroborates the validity of Oblongichnus and previous interpretation that the burrow was produced by infaunal, filter feeding bivalves with a foot of very limited horizontal movements. We found that the origin of oblong elongate bivalves may be dated back to the Ordovician, while an infaunal radiation likely occurred during late Paleozoic. We interpret that O. vulpesi was made in a moderate energy subtidal marine setting during the last marine highstand.

Survey of potential parasitoids (Hymenoptera) of Drosophila suzukii (Diptera: Drosophilidae) in Buenos Aires province, Argentina

Drosophila suzukii (Matsumura) is a pest that affects a great variety of fruit crops. The objective of this work was to learn about the diversity of parasitoids (Hymenoptera) that might be associated with SWD in fruit crops located in northeastern Buenos Aires province, Argentina. Species were identified as Euxestophaga argentinensis Gallardo, Ganaspis pelleranoi (Brèthes), Leptopilina boulardi (Barbotin, Carton & Kelner-Pillault), Hexacola bonaerensis Reche (Cynipoidea, Figitidae), Trichopria anastrephae (Costa Lima) (Diaprioidea, Diapriidae) and Pachycrepoideus vindemmiae (Rondani) (Chalcidoidea, Pteromalidae). Leptopilina boulardi, E. argentinensis and T. anastrephae were reported for the first time in the Buenos Aires province.

Tropical Kingbird (Tyrannus melancholicus) feeding a fledgling with Blue Passionflower (Passiflora caerulea) fruit

The Tropical Kingbird (Tyrannus melancholichus) feeds mostly on flying insects, but it can also supply its diet with other arthropods, fruits, and even small vertebrates. Despite being one of the most common birds in the Neotropics, knowledge about its foraging behavior is scarce. In December 2020, we observed and videotaped an adult feeding a fledgling with pulp and seeds of Blue Passionflower (Passiflora caerulea) in Ranchos, northeastern Buenos Aires province, Argentina. The whole event lasted 3:37 min. This is the first time that this foraging and breeding behavior is reported for the Tropical Kingbird.

Pleistocene Ophiomorpha nodosa from Buenos Aires, Argentina: Paleoenvironmental implications for ghost shrimp trace fossils along South America

Ophiomorpha nodosa Lundgren1891 is described from Puente de Pascua Formation Late Pleistocene of northeastern Buenos Aires province. The pelletal morphology and the base of ramifications of O. nodosa burrows are compared with mid-Holocene, Late Pleistocene Pehuen-Có locality and southern Brazil records. The preservation between sites differs in the degree of erosion and weathering, in situ or ex situ provenance, fragmentary shafts with or without branching and degree of cementation. These comparisons between sites suggest that different environmental conditions have generated the accumulation of trace fossils in transgressive and highstand depositional environments from foreshore through offshore. Neoichnological observations ascribe the burrowing of Ophiomorpha to ghost shrimps. For South American records Audacallichirus (formerly Sergio) mirim Rodrigues and Hödl, 1990 has been suggested as the producer, due to the similarity in morphology between modern and fossil burrows, and geographic distribution of ghost-shrimps. Finding of a widespread ichnotaxon possibly produced by the same taxon in different environmental conditions in the southwestern Atlantic suggests behavioral plasticity. The paleoenvironment of Puente de Pascua Formation in the level with Ophiomorpha burrows is interpreted a tidal flat in intertidal to subtidal depositional environments and relatively calm waters.

Molecular detection of Rickettsia bellii in Ixodes loricatus (Acari: Ixodidae) ticks associated with rodents from Buenos Aires province, Argentina

The aim of this study was the detection of Rickettsia in ticks of sigmodontine rodents from Northeastern Buenos Aires province, Argentina. A total of 222 rodents were captured collecting 10 ticks identified as Ixodes loricatus Neumann, which were analysed by the real-time PCR and conventional PCR techniques. DNA of Rickettsia bellii was detected in nymphs obtained from the rodents Akodon azarae Fischer, Oxymycterus rufus Fischer and Deltamys kempi Thomas. This is the first report of R. bellii infecting I. loricatus in Argentina and the first report of this bacterium associated with ticks of sigmodontine rodents

First Record of the Co-Occurrence of Platyxanthid and Varunid Crabs from Mid-Holocene Deposits of Northeastern Buenos Aires Province, Argentina. Paleoenvironmental Implications

Fossil fingers of crabs (Decapoda, Brachyura) coming from mid-Holocene deposits, Cerro de la Gloria, and Destacamento Rio Salado members, from northeastern Buenos Aires, Argentina are herein described. These fossil fingers represent the first record of Danielethus crenulatus, and the first record of varunids from the Canal 15 site. The specimens show diagnostic features and confirm the presence of subtidal-intertidal crabs at least from the mid-Holocene marine transgressive and regressive system tracts. This study also suggests that D. crenulatus could have been represented by large populations as in modern environments since food items (mollusks) were abundant during the mid-Holocene. Moreover, varunids, which feed on detritus, might also have had availability of organic matter during the late Quaternary according to previous fossil fauna records from other sites of Buenos Aires Province and Uruguay, because the coastal plains were extensively developed. These crabs constitute important food items for a diverse fauna and modify the substrate allowing the settlement of a varied coastal flora and fauna.

Possible ghost-shrimp burrows from the mid-Holocene of northeastern Buenos Aires, Argentina: Implications for breeding and postlarval settlement behavior

Large and tiny Ophiomorpha nodosa Lundgren, 1891 and Thalassinoides suevicus Rieth, 1932, and the postlarval chamber Maiakarichnus currani, are described from the mid-Holocene Destacamento Río Salado Member (northeastern Buenos Aires province, Argentina). Large specimens of O. nodosa consist of variably bifurcated horizontal galleries, connected in some cases by vertical shafts, and lined with pellets of different shape. Large T. suevicus are fewer and possess smooth outer walls. The smaller burrows of O. nodosa and T. suevicus are only a few centimeters from or even embedded in, the outer wall of the larger burrows, and are interpreted as the first settlement traces. A revised diagnosis of the spheroidal chamber M. currani, connected with O. nodosa and probably with T. suevicus, is submitted. The probable producer of these burrows and chambers is the ghost-shrimp Audacallichirus mirim. Morphological descriptions and burrowing behavior of A. mirim in modern and fossil populations from Argentina and Brazil suggest that this producer is represented at a higher level of ichnological abundance than previously recorded.

Molecular detection and identification of Rickettsia felis in Polygenis (Siphonaptera, Rhopalopsyllidae, Rhopalopsyllinae) associated with cricetid rodents in a rural area from central Argentina.

The aim of this study was to detect and identify the presence of Rickettsia in fleas associated with cricetid rodents from northeastern Buenos Aires Province, Argentina. Sixteen fleas belonging to three species of Polygenis were collected from 56 cricetid rodents and analyzed for the presence of Rickettsia performing the conventional polymerase chain reaction (PCR) technique. Only one specimen of Polygenis (Polygenis) axius axius collected from Oxymycterus rufus was positive for Rickettsia felis using the gltA gene, and to ompA gene. This is the first report of R. felis in a Rhopalopsyllidae flea from Argentina, and the first detection of this bacterium in P. (P.) a. axius. Since both, O. rufus and P. (P.) a. axius, are common in areas close to humans, and enzootic cycle of R. felis is not fully understood, the results herein obtained might be of epidemiological importance. Further studies are needed in order to analyze the capacity of the species of Polygenis to transmit R. felis.

Bryozoans and borings from Destacamento Río Salado Member (Buenos Aires Province, Argentina): Systematics and palaeoenvironment

This study describes and discusses bryozoan taxa and borings associated with carbonate fragments and bioclasts from Destacamento Río Salado Member, Canal de las Escobas Formation, mid-Holocene of northeastern Buenos Aires Province, Argentina. Three species of encrusting bryozoans were found co-occurring with borings: Biflustra puelcha, Conopeum reticulum and Electra arcuata comb. nov. In addition, bilaminar fragments of Hippomonavella charrua showing considerable surface abrasion were also found among the carbonate clasts. C. reticulum, formerly regarded as a cryptogenic species in Argentine harbours, is present in the Southwest Atlantic at least since the mid-Holocene, so it should be considered as a native species in the area. Borings comprise Gastrochaenolites isp., Trypanites isp., Maeandropolydora isp., Entobia isp. and Caulostrepsis isp. The co-occurrence of bryozoans and borings suggests that the carbonate fragments were transported from an abrasion platform when they were already bored, and then they were encrusted by the bryozoans at the study site, a tidal flat depositional environment.

The melittofauna and its floral associations in a natural riparian forest in Buenos Aires province, Argentina

This study estimates the diversity, abundance and floral associations of native wild bees present in a nature reserve in Buenos Aires, Argentina. The study included monthly sampling from September to April for two consecutive seasons (2011–2013). Bees were collected using entomological nets and pan traps along transects in the reserve area. A total of 1102 specimens belonging to 87 wild bee species/morphospecies in 37 genera of five families were collected. The families with the highest numbers of species were Apidae, followed by Halictidae and Megachilidae. A total of 63 species/morphospecies of plants belonging to 20 families were visited by bees. Asteraceae received the most visits, followed by Fabaceae and Onagraceae. Wild bee/plant interactions were studied through niche breadth and niche overlap. The highest values for niche breadth were found in two social species (Bombus pauloensis and Augochlora amphitrite) and niche overlap was predominantly low among bee species. Our results suggest that the nature reserve “Reserva Natural Integral Punta Lara” in northeastern Buenos Aires Province, Argentina, is an important natural area that supports a diverse community of wild bees.

El registro paleoambiental del Pleistoceno tardío al presente en la Laguna de Lobos, Buenos Aires, Argentina

Se caracterizó el medio físico del ambiente, la fisiografía, régimen hidrológico y la historia geológica de la cubeta lagunar. La geología superficial está representada por seis unidades litoestratigráficas y dos pedoestratigráficas, que abarcan del Pleistoceno temprano al tardío y del Holoceno medio al presente. La más antigua, la Formación Ensenada, constituye el sustrato regional, sobre el cual se ubican cuatro unidades eólicas, las Formaciones Buenos Aires, La Postrera I, III y IV, los Geosuelos Sin Nombre y Puesto Berrondo y el Aluvio reciente. Los sedimentos colmatantes fueron obtenidos mediante perforaciones, reconociéndose siete unidades litoestratigráficas (cinco subácueas y dos subaéreas). Las subácueas corresponden a la Formación Luján, Miembros La Chumbiada, Lobos, Río Salado y Monte (Pleistoceno tardío al Holoceno tardío) y al Aluvio reciente. Los depósitos subaéreos a las Formaciones La Postrera I y IV del Pleistoceno tardío y Holoceno tardío-tardío, respectivamente. La excavación de la cubeta se inició en la etapa seca del ?Bonaerense?, la posterior alternancia climática: seco-húmedo facilitó la evolución. Las etapas secas se caracterizaron por deflación, generación de cubetas, sabkhas o lagos salados, precipitación de sales y acumulación de depósitos eólicos. En las húmedas predominó la sedimentación y la pedogénesis. De esta manera, el conjunto de depósitos posteriores a la Formación Ensenada está representado por cinco episodios de clima seco, que abarcan del Glacial Temprano a la Pequeña Edad de Hielo y cinco húmedos, cuyas acumulaciones límnicas conforman los cuatro miembros de la Formación Luján, el aluvio actual y los suelos sincrónicos S4, S1 y S0.

Southernmost record of Yellow-headed Vulture, Cathartes burrovianus Cassin, 1845 (Cathartiformes, Cathartidae), in Buenos Aires province, Argentina

We report the southernmost record of Yellow-headed Vulture, Cathartes burrovianus, in Punta Piedras, north-eastern Buenos Aires province, Argentina. This record implies the presence of this species in a new habitat: the Pampas ecoregion. Considering this and other records in Argentina and Uruguay, the species distribution could be extending south from its known range.

Recent changes in animal and plant distribution in the southern extreme of the Paranaense biogeographical province (northeastern Buenos Aires province, Argentina): ecological responses to climate change?

La region norte de la provincia de Buenos Aires, en Argentina, sufrio un incremento ininterrumpido de los valores de precipitaciones y temperatura durante las ultimas decadas. El objetivo de la presente contribucion es analizar los efectos de dicho cambio climatico en la distribucion de la fauna y flora local. El analisis resulto en el reconocimiento de corrimientos en la distribucion de un total de 117 especies. Estos cambios fueron representados por una expansion hacia el sur progresiva de especies presentes tipicamente en areas subtropicales. Como todos estos cambios tienen una orientacion y direccion similar, e incluyen un gran numero de plantas y animales con diferentes requerimientos ecologicos, se concluye que estos cambios de distribucion geografica son probablemente una respuesta a la alteracion climatica.

Parasitism by Botflies Philornis Sp. on European Starlings Sturnus vulgaris, an Exotic Bird in Argentina

We studied the parasitism of the exotic European starling Sturnus vulgaris by native botflies Philornis spp. in Argentina. We installed thirty nest boxes in the northeastern Buenos Aires province in the 2010–2011 breeding season. In the first brood, subcutaneous larvae of Philornis (Muscidae) parasitised 34 nestlings (89.4%) of 11 clutches (91.6%) and only three nestlings fledged. In the second brood, Philornis parasitised 15 (48.3%) nestlings of seven clutches (70%) and all the nestlings died. Compared to the mortality of other Neotropical birds parasitised by Philornis, the mortality in European starling nests is the highest found in the region. Our results show that the studied population of European starling suffers a high level of parasitism by Philornis, although this factor was not directly associated with the high mortality of starling nestlings. The fact that most non-parasitised nestlings also died indicates that other factors are also affecting nestling survival. Experiments that allow us to isolate the effect of Philornis from other variables would be needed to evaluate the impact of botfly larvae on starling nestlings.

Stability and change through time in the dialects of a Neotropical songbird, the Rufous-collared Sparrow

Behavioural characters that are learned can show temporal variation resulting from changes introduced in new generations during the learning process. The song of the Rufous-collared Sparrow (Zonotrichia capensis) shows significant geographical variation associated with habitat, delimiting song dialects. To study the temporal stability or change in dialects of Rufous-collared Sparrows at a microgeographical scale, we compared recordings made at Reserva El Destino, in north-eastern coastal Buenos Aires Province, Argentina, during 1987 and 2000 with recordings made during 2010 and 2011. We found that the geographical boundaries of the dialects remained stable over the period of 24 years. As we did not detect gross changes in the habitat of the study area over that period, we conclude that habitat is an important factor in maintaining geographical boundaries of dialects. Within the dialects, variation in some variables detected between 1987 and 2000 persisted to 2010–11 whereas other variables showed reversal over that period. These findings are consistent with the hypothesis that some changes in song were the result of neutral variation, whereby changes resulting from random factors, such as copying error, could have been maintained or introduced across generations. Our results show that comparing more than two points in time is fundamental to a better understanding of temporal variation of song and its possible causes.

A new species of Castianeira Keyserling (Araneae, Corinnidae) from Buenos Aires, Argentina

A new species of the spider genus Castianeira (Araneae: Corinnidae) from Argentina, C. coquito, is described on the basis of male and female specimens collected in northeastern Buenos Aires Province and the Ciudad Autónoma de Buenos Aires, Argentina. This new species is characterized by its diminutive size and by the very globose copulatory bulb with a thick neck. It is the sixth species of the genus reported for the country.

Uso de hábitat por aves en rellenos sanitarios del noreste de la provincia de Buenos Aires, Argentina

(Palabras clave: residuos, gaviotas, palomas, ambientes disturbados, antropizacion y avifauna, rellenos sanitarios) ABSTRACT. Habitat use by birds in landfills of northeastern Buenos Aires province, Argentina: Rubbish dumps and landfills are attractive sites for different species of opportunistic birds which can increase their populations on the food supplement offered by organic waste. These birds can act like vectors of diseases or polluting agents, damage agriculture, increase the risk of bird strikes, and have negative effects on other species through competition or predation. The goals of this work are to identify and quantify the species of birds and their habitat use within three landfills of the northeast of the Buenos Aires province, and to determine the importance of the waste amount deposited on these variables during two consecutive winter periods. Total bird abundance was different between landfills in both winters, and gulls predominated in the three landfills. North 3 landfill had the greater abundance of gulls and doves. Wading birds were significantly more abundant in Gonzalez Catan Landfill, and the birds of prey had similar abundances in the three landfills in both periods. In both periods, the gulls were abundant in all habitats of three landfills, whereas only the abundance of doves in North 3 landfill was related to the final waste disposition sites and to the near edge (<200m) area. Exposed waste in surface was positively correlated with total bird abundance and the abundance of doves, which are themselves related to the daily amount waste deposited. Reduction of the organic portion and waste handling during the final disposition, habitat management around the final disposition sites, together with both passive and active direct control methods would reduce the abundance of birds in landfills and their negative potential effects on man and the environment.

Taphonomic Analysis of Micromammal Remains from Striped Owl (Pseudoscops clamator) Pellets in Northeastern Buenos Aires Province, Argentina: Implications for Archaeological Sites Formation

AbstractThe main objective of this study was to determine the taxonomic and taphonomic characteristics of the micromammal remains recovered from pellets of Pseudoscops clamator (striped owl), collected at three localities in northeastern Buenos Aires Province, Argentina (Punta Lara Natural Reserve, 34°49'02,6''S, 58°03'03,9''W; Costanera Sur Ecological Reserve, 34°36'6,44" S, 58°21'33,22" W; Los Robles Park, 34°40'22,03''S, 58°52'18,88''W). The main taphonomic variables (e.g. evidence of digestive action, breakage patterns and relative abundance of skeletal elements) suggest that this owl mainly produces intermediate to moderate modification. On the other hand, P. clamator preyed mainly upon large‐sized (&gt;150 g) micromammals (e.g. Lutreolina crassicaudata, Cavia aperea, Holochilus brasiliensis and Rattus sp.), and to a lesser degree on medium‐ (50–150 g) and small‐sized species (&lt;50 g) (e.g. Scapteromys aquaticus, Calomys sp., Oligoryzomys flavescens, Akodon azarae and Mus musculus). Fossil assemblages with a dominance of large‐sized micromammals are commonly associated with humans as agents of accumulation. However, this study demonstrates that this owl produces assemblages with abundant large‐sized micromammals, which introduces an equifinality problem. In that sense, digestive corrosion marks, breakage patterns and the relative abundance of skeletal remains are the main attributes to differentiate P. clamator from humans, as agents of accumulation. Finally, our results might serve as an analytical model for the taphonomic interpretation of the fossil record of micromammals from paleontological and archaeological sites, which fall within the distributional range and habitat of P. clamator. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Abnormalities in amphibian populations inhabiting agroecosystems in northeastern Buenos Aires Province, Argentina

The occurrence of abnormalities in amphibians has been reported in many populations, and its increase could be related to environmental pollution and habitat degradation. We evaluated the type and prevalence of abnormalities in 5 amphibian populations from agroecosystems with different degrees of agricultural disturbance (cultivated and reference areas). We detected 9 types of abnormalities, of which the most frequent were those occurring in limbs. The observed prevalence of abnormality in assessed populations from cultivated and reference areas was as follows: Rhinella fernandezae (37.1 and 10.2%, respectively), Leptodactylus latrans adults (28.1 and 9.2%) and juveniles (32.9 and 15.3%), and Hypsiboas pulchellus (11.6 and 2.8%). Scinax granulatus populations did not show abnormalities. Pseudis minuta, which was only detected in the reference area, exhibited a prevalence of 13.3%. For R. fernandezae, L. latrans, and H. pulchellus, generalized linear mixed models showed that prevalence of abnormalities was significantly higher (p < 0.05) in cultivated than in reference areas. L. latrans juveniles were more vulnerable to abnormalities than adults (p < 0.05). The presence of abnormalities in some species inhabiting different agroecosystems suggests that environmental stress factors might be responsible for their occurrence. While we detected pesticides (endosulfan, cypermethrin, and chlorpyrifos) and lower dissolved oxygen levels in ponds of the cultivated area, no data are currently available on how other factors, such as injuries from predators and parasite infections, vary by land use. Further research will be necessary to evaluate possible causes of abnormalities detected in the present study mainly in the context of factor interactions.

Presencia del género Ctenomys (Rodentia, Ctenomyidae) en el noreste de la provincia de Buenos Aires, Argentina

Presence of the genus Ctenomys (Rodentia, Ctenomyidae) in northeastern Buenos Aires province, Argentina. The genus Ctenomys found at the locality of Lima, in the northeastern region of Buenos Aires province, is reported in this paper. The finding of specimens of this genus is located more than 150 kilometers to the North of previous mentions for the province, being possible its adcription to C. talarum or to any other species from the mesopotamian region of Argentina. Previous papers indicate the presence of fossil Ctenomys in several localities in northern Buenos Aires province, and suggest that the genus disappeared from this region before the XIXth century. Thus, the record of living Ctenomys in northeastern Buenos Aires province provide new interesting clues about the biogeography of this genus in the area.