Were some dinosaurs gregarious?

A careful survey of the dinosaur footprints and trackways (identified as Eubrontes, Anchisauripus and Grallator) at the Mt. Tom site north of Holyoke, Massachusetts, and plots of their orientations reveal that an improbable percentage (70%) of the tracks are oriented in a nearparallel course. All but one of these coincident ancient traverses were probably made by the same kind of Triassic dinosaur (the footprints of which are referred to as Eubrontes). Comparable trackway orientation patterns have been reported by Albritton (1942) near Comanche, Texas for an Early Cretaceous dinosaur (iguanodobntid?) and Bird (1941, 1944) cited paralled sauporod trackways of Early Cretaceous age near the Paluxy River in Texas. Probability dictates that these sub-parallel traverses were not independent events and the presence of other deviating trackways at all three sites indicates that the trackmakers probably were not confined in their passage by physical barriers. Furthermore, the coincidental occurrence of such natural barriers at all of the sites mentioned here seems highly improbable. the combinedevidence of the Massachusetts site and the two Texas localities, together with the apparently widespread occurrence of dinosaur trackway lineation, strongly indicates gregarious habits for several different kinds of dinosaurs.     

Double invasion of Tertiary island South America by ancestral New World monkeys?

Comparative Determinant Analysis was used to characterize antigenic determinants from 69 functionally diverse serum proteins for the phylogenetic study of anthropoid cladogenesis, of which 32 homologues with 66 antigenic determinants were compared between Lagothrix lagotricha and Cebus albifrons. Nine epitopes (one each of complement factors Cls, C3, C6, C7, C9, factor B, retinol-binding protein, β₂-glycoprotein III, and histidine rich α₂-glycoprotein) defined a robust clade uniting Lagothrix lagotricha with the Old World primates Macaca, Papio and Homo to the exclusion of Cebus albifrons. This tree indicates platyrrhine paraphyly or demonstrates an accelerated antigen substitution rate of Cebus when compared with Lagothrix. Narrow phylogenetic sampling does not permit the final resolution of this problem but strongly different evolutionary rates are considered unlikely because ancestral serum protein determinants, which are plesiomorphic for Primates as an order, are equally conserved in both Cebus and Lagothrix. If platyrrhine paraphyly is correct, our molecular-immunological clock estimates a divergence date of Cebus of 52.5 × 10⁶ years before present, i.e. 6.5 × 10⁶ years before the ateline clade diverged (possibly at 46.0 × 10⁶ years BP) from catarrhine ancestors. A scenario of platyrrhine paraphyly implies the necessity for double invasion of the isolated Tertiary South American island continent by primates across open ocean, and suggests a considerably earlier phylogenetic emergence of platyrrhines than is proposed by the oldest simian fossils from the Neotropics.     

Have natural disasters created opportunities to initiate Big Cat Tourism in South America?

Livestock is the predominant biomass in terrestrial systems around the world, and conflict with livestock inventories continues to threaten large carnivore persistence in increasingly fragmented habitats. Nevertheless, social tolerance for large carnivores is increasing, as is interest in predator tourism, which can facilitate wildlife–livestock coexistence strategies. We report two case studies in which natural disasters led to a reduction in local livestock inventories, and subsequent economic hardships that in turn created opportunities for initiating predator tourism: jaguar tourism in the Pantanal of Brazil and puma tourism in the Patagonia steppe grasslands of southern Chile. Any time livestock numbers are reduced, whether through management decisions or natural disasters, may be considered opportunities to reduce dependency upon livestock and to weigh diversifying revenue streams via alternative activities, such as tourism. Livestock reductions in combination with a surge in the global demand for wildlife tourism have made jaguar and puma tourism an increasingly important economic activity for both regions. Well-managed predator tourism can be effective carnivore conservation, and if integrated among other strategies, can augment conservation agendas.     

Does Acacia dealbata express shade tolerance in Mediterranean forest ecosystems of South America?

The distribution of Acacia dealbata Link (Fabaceae) in its non-native range is associated with disturbed areas. However, the possibility that it can penetrate the native forest during the invasion process cannot be ruled out. This statement is supported by the fact that this species has been experimentally established successfully under the canopy of native forest. Nonetheless, it is unknown whether A. dealbata can express shade tolerance traits to help increase its invasive potential. We investigated the shade tolerance of A. dealbata under the canopy of two native forests and one non-native for three consecutive years, as well as its early growth and photosynthetic performance at low light intensities (9, 30, and 70 μmol m⁻²sec⁻¹) under controlled conditions. We found many A. dealbata plants surviving and growing under the canopy of native and non-native forests. The number of plants of this invasive species remained almost constant under the canopy of native forests during the years of study. However, the largest number of A. dealbata plants was found under the canopy of non-native forest. In every case, the distribution pattern varied with a highest density of plants in forest edges decreasing progressively toward the inside. Germination and early growth of A. dealbata were slow but successful at three low light intensities tested under controlled conditions. For all tested light regimes, we observed that in this species, most of the energy was dissipated by photochemical processes, in accordance with the high photosynthetic rates that this plant showed, despite the really low light intensities under which it was grown. Our study reveals that A. dealbata expressed shade tolerance traits under the canopy of native and non-native forests. This behavior is supported by the efficient photosynthetic performance that A. dealbata showed at low light intensities. Therefore, these results suggest that Mediterranean forest ecosystems of South America can become progressively invaded by A. dealbata and provide a basis for estimating the possible impacts that this invasive species can cause in these ecosystems in a timescale.     

Is genetic variability so important? Non-native salmonids in South America

Three salmonid species introduced in Patagonian national parks in Argentine have experienced different degrees of expansion. Atlantic salmon Salmo salar is restricted to a few river-lake systems and its populations have been declining over recent years. Both rainbow Oncorhynchus mykiss and brown trout Salmo trutta populations have expanded from their introduction sites and now occupy a wide range of freshwater ecosystems. Genetic variation at the same neutral markers (microsatellite loci) was examined for different populations of the three species acclimatized to the same areas, and compared with that of native populations. Founder effects denoted as reduced variability and great differentiation with respect to the native populations were detected. Significant reduction in variability has not been an obstacle for successful adaptation of rainbow and brown trout, indicating that genetic variability per se cannot be claimed as the reason for their different outcomes in the new habitats.     

Whistle variability of Guiana dolphins in South America: Latitudinal variation or acoustic adaptation?

A previous comparison of whistles using data sampled at 48 kHz suggested that certain frequency parameters vary along a latitudinal gradient. This geographical pattern may be biased because whistles sampled at higher frequencies could potentially have very different frequency contents. The current study compared the acoustic parameters of Guiana dolphin (Sotalia guianensis) whistles recorded at a higher sampling rate (96 kHz) and from groups occupying two never before sampled sites, Benevente Bay, Espírito Santo, Brazil, and Formosa Bay, Rio Grande do Norte, Brazil, with recordings of other populations in South America. By only considering data sampled at a rate of at least 96 kHz, we aimed to detect differences in whistles across locations. Contrary to previous findings, our analyses do not indicate any clear separation between northern and southern populations based on whistles, and do not corroborate the hypothesis of latitudinal acoustic variation in this species. The variation in Guiana dolphin whistle parameters found here appears to be influenced by latitude to some extent, but several other factors, including sampling method, environmental fluctuations, and social influence on vocal learning, may be confounding the detection of a geographic pattern in these whistle samples.     

Who’s afraid of perfectionist moral enhancement? A reply to Sparrow

Robert Sparrow recently argued that state-driven moral bioenhancement is morally problematic because it inevitably invites moral perfectionism. While sharing Sparrow’s worry about state-driven moral bioenhancement, I argue that his anti-perfectionism argument is too strong to offer useful normative guidance. That is, if we reject state-driven moral bioenhancement because it cannot remain neutral between different conceptions of the good, we might have to conclude that all forms of moral enhancement programs ought not be made compulsory, including the least controversial and most popular state-driven program: compulsory (moral) education. In this paper, I argue that, instead, the spirit of Sparrow’s worry should be recast in the language of the capability approach—an approach that strives to enhance people’s capabilities to develop their own conceptions of the good by restricting itself from endorsing thick conceptions of the good. The distinction made regarding thick and thin conceptions of the good helps to capture sentiments against state-driven bioenhancement programs without falling prey to the issues I raise against Sparrow’s anti-perfectionist arguments.     

Whither Latin America? Trends and challenges of science in Latin America

Science in Latin America has experienced vigorous growth in the past decade, as demonstrated by the fact that the Latin American share of the world's scientific publications increased from 1.8% in 1991-1995 to 3.4% in 1999-2003. Significant growth has also taken place in the numbers of PhDs in science and engineering (S&E) awarded in Latin American countries in recent years, including those in the natural sciences. Importantly, albeit at different rates, growth has been verified in almost all countries in the region, indicating a general effort to promote the development of S&E. In most research fields, however, the recognition or relative impact of Latin American science, as measured by the average number of citations received by published articles (CpP), is still below world averages and much lower than in developed nations. We show that average CpP values for a set of 34 representative developing and developed countries correlate significantly with gross expenditure in research and development (GERD), with gross domestic product (GDP) per capita and with the number of researchers per million inhabitants (RpM). Among those countries, Latin American nations present some of the lowest average values of CpP (<6), GERD (< or =1% of GDP) and RpM (<2,000). We also examined recent trends in scientific activity in Latin America, with focus on the natural sciences and on biochemistry and molecular biology (BMB). In terms of citation scores, publications in BMB compare favorably to those in other research fields within Latin America. At the same time, however, Latin American BMB is one of the areas for which relative impact--compared to developed nations or normalized to world averages--is lowest. These observations clearly indicate the need to establish effective policies to increase competitiveness in terms of the quality and international recognition of Latin American natural sciences in general, and BMB in particular, as opposed to merely increasing the absolute numbers of publications or the numbers of PhDs awarded in the region.     

On the spread of the Russian sturgeon Acipenser gueldenstaedtii (Acipenseriformes: Acipenseridae) in the Neotropics: A marine path to invade freshwater drainages in South America?

Acipenser gueldenstaedtii is a species of sturgeon described from Caspian Sea and Black Sea and their tributaries, occurring in the Eastern Atlantic, Europe and Middle East. This and other two sturgeon species have been accidentally introduced in the Rio Negro, Uruguay, a tributary of the Rio de La Plata. Recently, it has been demonstrated the presence and establishment of A. gueldenstaedtii widespread in the Rio Paraná basin, the largest tributary of the Rio de La Plata, corresponding to the second largest river drainage in the Neotropics. We herein register the presence of the species in the next northern freshwater drainage in South America, representing the first record for Brazil. We further discuss the possibility of dispersal through marine environments to other freshwater drainages in South America through the analysis of its documented occurrence and marine ecoregions in southwestern Atlantic.     

Out of South America? Additional evidence for a southern origin of melanopline grasshoppers

Molecular phylogenetic methods provide a useful tool for critically evaluating competing biogeographic hypotheses. This paper focuses on conjectures at the intercontinental level. An earlier phylogeographic study of the grasshopper subfamily Melanoplinae examined relationships among taxa occupying the Americas and Eurasia. The objective was to test which of three scenarios best described the subfamily's origins and patterns of intercontinental movement. It was tentatively proposed that the melanopline grasshoppers evolved somewhere in the Americas and spread to the Old World. The present article, by including additional Neotropical species, not only upholds that conjecture, but is able to identify South America as the site of origin. Phylogenetic analysis indicates a direction of dispersal: South America-->North America-->Eurasia, that is opposite to what was previously believed. This study also provides, for the first time, a preliminary molecular phylogeny of selected South American melanopline genera.     

Does morphological convergence imply functional similarity? A test using the evolution of quadrupedalism in ornithischian dinosaurs

Convergent morphologies are thought to indicate functional similarity, arising because of a limited number of evolutionary or developmental pathways. Extant taxa displaying convergent morphologies are used as analogues to assess function in extinct taxa with similar characteristics. However, functional studies of extant taxa have shown that functional similarity can arise from differing morphologies, calling into question the paradigm that form and function are closely related. We test the hypothesis that convergent skeletal morphology indicates functional similarity in the fossil record using ornithischian dinosaurs. The rare transition from bipedality to quadrupedality occurred at least three times independently in this clade, resulting in a suite of convergent osteological characteristics. We use homology rather than analogy to provide an independent line of evidence about function, reconstructing soft tissues using the extant phylogenetic bracket and applying biomechanical concepts to produce qualitative assessments of muscle leverage. We also optimize character changes to investigate the sequence of character acquisition. Different lineages of quadrupedal ornithischian dinosaur stood and walked differently from each other, falsifying the hypothesis that osteological convergence indicates functional similarity. The acquisition of features correlated with quadrupedalism generally occurs in the same order in each clade, suggesting underlying developmental mechanisms that act as evolutionary constraints.     

Convergent evolution of gigantism in damselflies of Africa and South America? Evidence from nuclear and mitochondrial sequence data

Extreme large body size is rare in modern Zygoptera (damselflies). Only the South and Central American damselfly family Pseudostigmatidae and one African species, Coryphagrion grandis, share the morphological trait of gigantism. By means of phylogenetic analyses using two mitochondrial markers (16S rDNA and ND1) and one nuclear marker (EF1) in combination with an existing morphological data set, we trace the evolution of gigantism in damselflies. Individual and combined data sets were analyzed using the maximum parsimony, minimum evolution and maximum likelihood algorithms. Regardless of the algorithm used and the data set analyzed all principal tree topologies support a monophyly of the damselfly taxa displaying giant body size. This supports the view that the evolution of gigantism in damselflies from Africa and South America is not the result of convergent evolution due to strikingly similar habitat preferences, but rather the result of close genealogical relationship. Because modern odonates evolved before the split of Africa from Gondwanaland, the proposed phylogeny suggests that C. grandis represents a Gondwana relict.     

The Evolution of the Cenozoic Terrestrial Mammalian Predator Guild in South America: Competition or Replacement?

South America was isolated from other continents during most of the Cenozoic, developing a singular mammalian fauna. In contrast to North America, Europe, Asia, and Africa, up to the late Neogene, the carnivore adaptive zone in South America was populated by crocodiles (Sebecidae), large snakes (Madtsoiidae), large birds (Phorusrhacidae), and metatherian mammals (Sparassodonta). Sparassodonta were varied and comprised a wide range of body masses (≈ 2–50 kg) and food habits. Their diversity decreased towards the late Miocene (Huayquerian Stage/Age) and the group became extinct in the “middle” Pliocene (≈ 3 Ma, Chapadmalalan Stage/Age). Several authors have suggested that the cause of this decline and extinction was the ingression of carnivorans to South America (about 6–7 Ma ago), because they competed with the Sparassodonta; although this hypothesis has been criticized in recent years. With the intention of testing the hypothesis of “competitive displacement,” we review the fossil record of South American Sparassodonta and Carnivora, collect data about diversity, estimate size and diet, and determine first and last appearances. The diversity of Sparassodonta is low relative to that of Carnivora throughout the Cenozoic with the early Miocene (Santacrucian Stage/Age) showing the greatest diversity with 11 species. In the late Miocene-middle Pliocene (Huayquerian Stage/Age), the fossil record shows overlap of groups, and the Sparassodonta’s richness curve begins to decline with the first record of Carnivora. Despite this overlap, carnivorans diversity ranged from four or fewer species in the late Miocene-Pliocene to a peak of around 20 species in the early Pleistocene (Ensenadan Stage/Age). Carnivora was initially represented by small-sized, omnivorous species, with large omnivores first appearing in the Chapadmalalan Stage/Age. Over this period, Sparassodonta was represented by large and small hypercarnivores and a single large omnivorous species. From this review of the fossil record, it is suggested that factors other than competitive displacement may have caused the extinction of the Sparassodonta.     

‘Inordinate Fondness’: A Threat to Beetles in South East Asia?

A recent report on trade in stag beetles and rhinoceros beetles in Japan highlights a number of issues of considerable importance for beetle conservation resulting from such trade over much of south east Asia. The popularity of these beetles has both positive and negative effects, and there is need for more effective control and monitoring of this trade to enhance positive values and reduce likely harm to species and habitats.