Ecological and evolutionary factors in the morphological diversification of South American spiny rats

Understanding the processes underlying morphological diversification is a central goal in ecology and evolutionary biology and requires the integration of information about phylogenetic divergence and ecological niche diversity. In the present study, we use geometric morphometrics and comparative methods to investigate morphological diversification in Neotropical spiny rats of the family Echimyidae. Morphological diversification is studied as shape variation in the skull, comprising a structure composed of four distinct units: vault, base, orognathofacial complex, and mandible. We demonstrate association among patterns of variation in shape in different cranial units, levels of phylogenetic divergence, and ecological niche diversification. At the lower level of phylogenetic divergence, there is significant and positive concordance between patterns of phylogenetic divergence and cranial shape variation in all cranial units. This concordance may be attributable to the phylogenetic and shape distances being calculated between species that occupy the same niche. At higher phylogenetic levels of divergence and with ecological niche diversity, there is significant concordance between shape variation in all four cranial units and the ecological niches. In particular, the orognathofacial complex revealed the most significant association between shape variation and ecological niche diversity. This association may be explained by the great functional importance of the orognathofacial complex.Facultad de Ciencias Naturales y Muse

Ecological and evolutionary factors in the morphological diversification of South American spiny rats

Understanding the processes underlying morphological diversification is a central goal in ecology and evolutionary biology and requires the integration of information about phylogenetic divergence and ecological niche diversity. In the present study, we use geometric morphometrics and comparative methods to investigate morphological diversification in Neotropical spiny rats of the family Echimyidae. Morphological diversification is studied as shape variation in the skull, comprising a structure composed of four distinct units: vault, base, orognathofacial complex, and mandible. We demonstrate association among patterns of variation in shape in different cranial units, levels of phylogenetic divergence, and ecological niche diversification. At the lower level of phylogenetic divergence, there is significant and positive concordance between patterns of phylogenetic divergence and cranial shape variation in all cranial units. This concordance may be attributable to the phylogenetic and shape distances being calculated between species that occupy the same niche. At higher phylogenetic levels of divergence and with ecological niche diversity, there is significant concordance between shape variation in all four cranial units and the ecological niches. In particular, the orognathofacial complex revealed the most significant association between shape variation and ecological niche diversity. This association may be explained by the great functional importance of the orognathofacial complex.Facultad de Ciencias Naturales y Muse

Gracilinanus microtarsus (Didelphimorphia: Didelphidae)

Gracilinanus microtarsus (J. A. Wagner, 1842), called the Brazilian gracile opossum, is a small didelphid that is 1 of 6 species in the genus Gracilinanus. It is a sexually dimorphic, solitary marsupial that has a highly seasonal reproductive pattern. It inhabits Atlantic rain forests and semideciduous forests interspersed in the highly seasonal cerrado (savanna-like vegetation) in southeastern and southern Brazil. It prefers locations associated with low canopy cover and it also occurs in habitats altered by anthropogenic events. The species is classified as Least Concern by the International Union for Conservation of Nature and Natural Resources. © 25 March 2010 by the American Society of Mammalogists

Ecological and evolutionary factors in the morphological diversification of South American spiny rats

Understanding the processes underlying morphological diversification is a central goal in ecology and evolutionary biology and requires the integration of information about phylogenetic divergence and ecological niche diversity. In the present study, we use geometric morphometrics and comparative methods to investigate morphological diversification in Neotropical spiny rats of the family Echimyidae. Morphological diversification is studied as shape variation in the skull, comprising a structure composed of four distinct units: vault, base, orognathofacial complex, and mandible. We demonstrate association among patterns of variation in shape in different cranial units, levels of phylogenetic divergence, and ecological niche diversification. At the lower level of phylogenetic divergence, there is significant and positive concordance between patterns of phylogenetic divergence and cranial shape variation in all cranial units. This concordance may be attributable to the phylogenetic and shape distances being calculated between species that occupy the same niche. At higher phylogenetic levels of divergence and with ecological niche diversity, there is significant concordance between shape variation in all four cranial units and the ecological niches. In particular, the orognathofacial complex revealed the most significant association between shape variation and ecological niche diversity. This association may be explained by the great functional importance of the orognathofacial complex.Facultad de Ciencias Naturales y Muse

Interaction Intimacy Affects Structure and Coevolutionary Dynamics in Mutualistic Networks

The structure of mutualistic networks provides clues to processes shaping biodiversity [1-10]. Among them, interaction intimacy, the degree of biological association between partners, leads to differences in specialization patterns [4, 11] and might affect network organization [12]. Here, we investigated potential consequences of interaction intimacy for the structure and coevolution of mutualistic networks. From observed processes of selection on mutualistic interactions, it is expected that symbiotic interactions (high-interaction intimacy) will form species-poor networks characterized by compartmentalization [12, 13], whereas nonsymbiotic interactions (low intimacy) will lead to species-rich, nested networks in which there is a core of generalists and specialists often interact with generalists [3, 5, 7, 12, 14]. We demonstrated an association between interaction intimacy and structure in 19 ant-plant mutualistic networks. Through numerical simulations, we found that network structure of different forms of mutualism affects evolutionary change in distinct ways. Change in one species affects primarily one mutualistic partner in symbiotic interactions but might affect multiple partners in nonsymbiotic interactions. We hypothesize that coevolution in symbiotic interactions is characterized by frequent reciprocal changes between few partners, but coevolution in nonsymbiotic networks might show rare bursts of changes in which many species respond to evolutionary changes in a single species. © 2007 Elsevier Ltd. All rights reserved

ATLANTIC EPIPHYTES: a data set of vascular and non-vascular epiphyte plants and lichens from the Atlantic Forest

Epiphytes are hyper-diverse and one of the frequently undervalued life forms in plant surveys and biodiversity inventories. Epiphytes of the Atlantic Forest, one of the most endangered ecosystems in the world, have high endemism and radiated recently in the Pliocene. We aimed to (1) compile an extensive Atlantic Forest data set on vascular, non-vascular plants (including hemiepiphytes), and lichen epiphyte species occurrence and abundance; (2) describe the epiphyte distribution in the Atlantic Forest, in order to indicate future sampling efforts. Our work presents the first epiphyte data set with information on abundance and occurrence of epiphyte phorophyte species. All data compiled here come from three main sources provided by the authors: published sources (comprising peer-reviewed articles, books, and theses), unpublished data, and herbarium data. We compiled a data set composed of 2,095 species, from 89,270 holo/hemiepiphyte records, in the Atlantic Forest of Brazil, Argentina, Paraguay, and Uruguay, recorded from 1824 to early 2018. Most of the records were from qualitative data (occurrence only, 88%), well distributed throughout the Atlantic Forest. For quantitative records, the most common sampling method was individual trees (71%), followed by plot sampling (19%), and transect sampling (10%). Angiosperms (81%) were the most frequently registered group, and Bromeliaceae and Orchidaceae were the families with the greatest number of records (27,272 and 21,945, respectively). Ferns and Lycophytes presented fewer records than Angiosperms, and Polypodiaceae were the most recorded family, and more concentrated in the Southern and Southeastern regions. Data on non-vascular plants and lichens were scarce, with a few disjunct records concentrated in the Northeastern region of the Atlantic Forest. For all non-vascular plant records, Lejeuneaceae, a family of liverworts, was the most recorded family. We hope that our effort to organize scattered epiphyte data help advance the knowledge of epiphyte ecology, as well as our understanding of macroecological and biogeographical patterns in the Atlantic Forest. No copyright restrictions are associated with the data set. Please cite this Ecology Data Paper if the data are used in publication and teaching events. © 2019 The Authors. Ecology © 2019 The Ecological Society of Americ

Biologia reprodutiva de Artibeus lituratus (Olfers, 1818) (Chiroptera: Phyllostomidae)

Some aspects of the reproductive biology of Artibeus lituratus are reported. The bats examined were collected monthly at the Estação Florestal Experimental Eng. Agr. Mario Xavier located at the Antiga Estrada Rio - São Paulo, Km 51, Seropedica, RJ. Histological sections were obtained from vagina, uterus, oviducts and ovaries in females and accessory glands, testis and epididymis in males. A lituratus is a monovular species since only one corpus luteum was found in each ovary and both ovaries are functional. A particular aspect is the engorgement of the oviductal epithelium with a PAS - substance during pre and pos ovulatory period. This engorgement can be restricted to one of the oviducts. The distal epithelium of vagina has a glandular appearance with cells reacting positively to the PAS procedure. Spermatogenesis seems to be continuous throughout the year since every adult male had active spermatogenesis in the testis and the epididymis packed with spermatozoa. Accessory glands consisted of paired Cowper's glands, a bilobulated seminal vesicle and a single prostate. Secretory blebs resulting from apocrine secretion were noticed in the lumina of tubules of seminal vesicle. Reproductive pattern seems to be seasonal poliestry since lactant females were collected with early embryos in uterus, and late pregnat and lactant females were found during the rainiest months of the year.CAPESEstuda os aspectos morfológicos da biologia reprodutiva e o padrão do ciclo reprodutivo anual de Artibeus lituratus. Os animais foram capturados na Estação Experimental Florestal Eng. Agr. Mário Xavier, situada no Km 51 da Antiga Estrada Rio-São Paulo, Seropédica, RJ. Foram efetuados cortes histológicos dos ovidutos, ovários e útero nas fêmeas e dos túbulos seminíferos, epidídimo, duto deferente e glândulas anexas nos machos. A vagina de A. lituratus apresentou, no terço distal, um epitélio glandular (PAS +), provavelmente mucosecretor, sendo que parece não haver referências à existência de epitélio glandular na vagina de mamíferos. O epitélio tubal apresentou acúmulo de substâncias (PAS -), principalmente ao nível da ampola e istmo nos períodos pré- e pós-ovulatório. Este acúmulo ocorreu nos dois ovidutos ou apenas em um, sendo que, neste caso, o acúmulo deu-se no oviduto correspondente contendo os maiores folículos em crescimento ou corpo amarelo recém-formado. A lituratus é uma espécie monovular, visto que somente um corpo amarelo foi encontrado em cada ovário. As glâdulas anexas do aparelho reprodutivo masculino consistem de glândulas de Cowper pares, vesícula seminal bilobulada e próstata simples. Há, na luz da vesícula seminal, corpúsculos esféricos semelhantes aos assinalados em espécies da família Pteropodidae. O ciclo reprodutivo parece ser do tipo poliéstrico estacional, pois observamos fêmeas lactantes e simultaneamente prenhes, com embriões em início de desenvolvimento no útero. O caráter estacional foi reconhecido pela captura de fêmeas em prenhez avançada e em lactação durante os períodos mais chuvosos do ano. A espermatogênese é contínua ao longo do ano visto que todos os machos adultos apresentavam espermatogênese ativa nos túbulos seminíferos e espermatozóides no epidídimo

The nested structure of marine cleaning symbiosis: is it like flowers and bees?

In a given area, plant–animal mutualistic interactions form complex networks that often display nestedness, a particular type of asymmetry in interactions. Simple ecological and evolutionary factors have been hypothesized to lead to nested networks. Therefore, nestedness is expected to occur in other types of mutualisms as well. We tested the above prediction with the network structure of interactions in cleaning symbiosis at three reef assemblages. In this type of interaction, shrimps and fishes forage on ectoparasites and injured tissues from the body surface of fish species. Cleaning networks show strong patterns of nestedness. In fact, after controlling for species richness, cleaning networks are even more nested than plant–animal mutualisms. Our results support the notion that mutualisms evolve to a predictable community-level structure, be it in terrestrial or marine communities

Relationships among didelphid marsupials based on sequence variation in the mitochondrial cytochrome B gene

Variation in the mitochondrial cytochrome b gene (nucleotide and amino acid sequences) is evaluated for 9 genera and 15 species of American opossums in the family Didelphidae, using the American caenolestid rat opossum Lestoros and the New Guinean peroryctid bandicoot Echimypera as outgroups. Phylogenetic analyses (parsimony and distance) strongly support the monophyly of the Didelphidae and delineate two major clades; (1) Didelphis and Philander are strongly aligned sister taxa, with Metachirus weakly but consistently associated with them, and (2) Marmosa plus Micoureus, with Monodelphis falling outside that pair. The genera Marmosops, Caluromys, and Glironia exhibit varied relationships, depending upon the method of analysis and data (DNA or amino acid sequences) used, but generally are placed individually or in combinations near or at the base of the didelphid radiation. Some aspects of these relationships are consistent with current taxonomic views, but others are in marked contrast. Specifically, a clade comprised of the mouse opossums Marmosa, Micoureus, and Marmosops is strongly rejected by log-likelihood analysis, contrary to expectations from some current classifications. Also, the woolly opossums Caluromys and Glironia also do not form a sister-taxon relationship, as suggested by their placement in a subfamily separate from the remaining didelphids examined. However, such a relationship cannot be rejected from log-likelihood analyses. The relationships suggested from cyt-b sequences are strongly concordant with those based on DNA-DNA hybridization analyses. In addition to systematic and phylogenetic properties, molecular evolution of the didelphid cytochrome b gene sequence is characterized according to nucleotide bias and rate differentials at each codon position and across the entire sequence. © 1996 Plenum Publishing Corporation