Fernando Carbayo

Land planarians (Platyhelminthes) as a model organism for fine-scale phylogeographic studies: understanding patterns of biodiversity in the Brazilian Atlantic Forest hotspot

The Brazilian Atlantic Forest is one of the richest biodiversity hotspots of the world. Paleoclimatic models have predicted two large stability regions in its northern and central parts, whereas southern regions might have suffered strong instability during Pleistocene glaciations. Molecular phylogeographic and endemism studies show, nevertheless, contradictory results: although some results validate these predictions, other data suggest that paleoclimatic models fail to predict stable rainforest areas in the south. Most studies, however, have surveyed species with relatively high dispersal rates whereas taxa with lower dispersion capabilities should be better predictors of habitat stability. Here, we have used two land planarian species as model organisms to analyse the patterns and levels of nucleotide diversity on a locality within the Southern Atlantic Forest. We find that both species harbour high levels of genetic variability without exhibiting the molecular footprint of recent colonization or population expansions, suggesting a long‐term stability scenario. The results reflect, therefore, that paleoclimatic models may fail to detect refugia in the Southern Atlantic Forest, and that model organisms with low dispersal capability can improve the resolution of these models.

The costs of describing the entire animal kingdom

In the otherwise excellent special issue of Trends inEcology and Evolution on long-term ecological research(TREE 25(10),2010), none of the contributors mentionedthe importance of natural history collections (NHCs) assources of data that can strongly complement past andongoing survey data. Whereas very few field surveyshave operated for more than a few decades, NHCs,conserved in museums and other institutions, comprisesamples of the Earth’s biota typically extending backwell into the nineteenth century and, in some cases,before this time. They therefore span the period ofaccelerated anthropogenic habitat destruction, climatewarming and ocean acidification, in many cases reflect-ing baseline conditions before the major impact of thesefactors.Natural history collections (NHCs) provide a rich source ofdata at thetaxic andcommunitylevels, andcan contributeto a wide range of studies [1]. These include biogeographicrange changes (spatial and/or altitudinal) [2]; phenologicalshifts (e.g. in flowering time [3]); and evolutionary change(genetic or morphological). They can also (if unsorted bulksamples are available) document changes in communitycomposition in the recent past (historical samples) andthrough deeper geological time (fossil samples). In addi-tion, museum specimens provide source material for arange of genetic, biochemical, isotopic and trace-elementstudies into organismal responses to environmentalchange (e.g. use of preserved feathers to trace changesin the diet and migration of birds [4]).NHCs comprise not only the products of opportunisticcollecting but are also (particularly in the major nationalmuseums and institutions) repositories of major surveys.The Natural History Museum (NHM) in London, UK, forexample, houses thousands of jars from the Discovery andChallenger marine expeditions that were collected at hun-dredsofstationsinthelatenineteenthandearlytwentiethcenturies. These samples provide an outstanding (andlargely untapped) resource for comparison with modernsurveydata.Collectionsmadewithacoherentandsystem-aticsamplingstrategyareinevitablymorelikelytoprovideresearch-quality material than ad-hoc or point samples.Unknown or inconsistent sampling strategy can bea problem, but this is not unique to museum collections;methodological changes or gaps also occur in long-termfielddatasetsandneedtobeaccommodatedintheanalysis[5].Of particular value, a proportion of historical and mod-ern collections comprise time-series (i.e. the same localityand/ortaxonhasbeenregularlycollectedovermanyyears).For exploration of long-term ecological responses, NHC-derived datasets can be integrated with local or regionalclimatic and other records, such as the Central EnglandTemperature Record, which is continuous back to 1659(http://hadobs.metoffice.com/hadcet/). Time-series throughmuch longer intervals of the Earth’s history are availablein palaeontological collections.Central to all such endeavours is the availability ofaccurate provenance data on the NHC material. Museumspecimenlabelsandregistersideallyindicatetheplaceanddate of collection. However, even when such information isavailable, considerable work may be required to make itaccessible for research, for example, by georeferencing(establishing the latitude and longitude of) obscureplace-names, and entering all records onto an electronicdatabase [2]. Collaboration between researchers and col-lectionsmanagersisessentialand,ifresourcesforcurationare limited, researchers should consider including collec-tions databasing into their funding proposals.Curators and collections managers, for their part, havea vital part to play in this process. Policies crucial forenabling collections-based research include:Maintaining unpicked sub-samples of bulk-sampledcollections.Prioritising databasing of collections with researchpotential.Facilitating responsible destructive sampling. Thisincludes retaining duplicate imperfect specimens forthe purpose, and simplifying paperwork.Maintaining and extending time-series through con-tinued collecting, and collaboration with modernsurveys to enable acquisition of voucher specimens.Collaboratingwithothermuseumstocreate,ultimately,an integrated global resource (e.g. through the SciCollinitiative: http://www.scicoll.org/).In a recent example embodying many of these aspects,the NHM, in a project funded by the UK Government,compiled a database on the extent of NHM and otherBritish collections potentially suitable for investigatingthe effects of ocean acidification on marine biocalcifyingorganisms. The results of the project, summarizingsamplesaccumulatedgloballyover200 years,are available

Terrestrial flatworm (Platyhelminthes: Tricladida: Terricola) diversity versus man-induced disturbance in an ombrophilous forest in southern Brazil

Terrestrial flatworms, or Terricola, are sensitive to environmentalchanges and therefore might be excellent indicators of the conservation statusof natural habitats. The present study aimed to answer two main questions: (1)is terrestrial planarian diversity affected by human disturbances, and (2) isthere any species or group of species that indicates such disturbance? The studysite, National Forest of São Francisco de Paula, Brazil, was originallycovered by a mixed ombrophilous forest, but successive reforestations andselective logging have modified the original landscape. We studied Terricoladiversity in the four main habitats in the study area: mixed ombrophilous forest(NA), ombrophilous forest with selective Araucariaangustifolia logging (N), A. angustifoliareforestation (A), and reforestation of Pinus elliottii(P). According to an increasing degree of disturbance, the habitats might beordered as follows: (NA)<(N)<(A)<(P). We conducted 24 surveys in eachhabitat over a period of 1 year. Our results indicate that: (1)Terricola diversity is inversely related to the degree of habitat disturbance;(2) there are species (Geoplana franciscana,Geoplana sp. 5, and possibly Geoplanidae 3 andNotogynaphallia guaiana) that prefer habitats located onthe extreme right along the main axis of a detrended correspondence analysisordination and therefore can be considered as indicators of well preserved,natural habitats. On the other hand there are species(Xerapoa sp. 1, Choeradoplanaiheringi, G. marginata sensu Marcus andGeoplana sp. 2) preferring more disturbed habitats, whichmay form biological indicators of such disturbances.

Two new genera of geoplaninid land planarians (Platyhelminthes : Tricladida : Terricola) of Brazil in the light of cephalic specialisations

Two new genera of geoplaninid land planarians are described. Cephalic specialisations, mainly external morphology and musculature development, partially define each genus. Cephaloflexa, gen. nov. shows some peculiar characteristics, such as a gradual narrowing of the anterior third of the body and an upwards roll of the anterior tip, the absence of eyes and sensory pits on the apex, and the existence of a retractor muscle derived from the ventral cutaneous longitudinal musculature. Geoplana bergi Graff, 1899 is allocated to Cephaloflexa and is designated as the type species. The ventral cutaneous longitudinal muscles of Supramontana, gen. nov. (monotypic), are partially sunk into the mesenchyme, thus constituting a cephalic retractor muscle. A new species of each genus is also described. The external morphology and anatomy of the cephalic region of the new genera and of Geoplana Stimpson, 1857, Choeradoplana Graff, 1896 and Issoca C. G. Froehlich, 1955 are analysed. Emendations to the diagnoses of Issoca and Choeradoplana are proposed based on cephalic differentiations. Spanish abstractSe decriben Cephaloflexa, gen. nov. y Supramontana, gen. nov., dos nuevos generos de planarias terrrestres de la subfamilia Geoplaninae, ambos caracterizados por especializaciones cefalicas, como la morfologia externa y el desarrollo muscular. Se describe una nueva especie de cada genero. Se transfiere Geoplana bergi Graff, 1899 para el genero Cephaloflexa y se la designa especie tipo. Cephaloflexa, gen. nov. presenta caracteristicas peculiares, como el tercio anterior del cuerpo muy fino, region anterior enrollada hacia el dorso, ausencia de ojos y fosetas sensoriales en el apice anterior del cuerpo, y un musculo retractor derivado de la musculatura subcutanea longitudinal ventral. Supramontana, gen. nov., genero monotipico, tiene parte de la musculatura subcutanea longitudinal ventral hundida en el mesenquima y transformada en la region anterior en un musculo retractor cefalico. Se analiza la morfologia externa y la anatomia de la region cefalica de Geoplana Stimpson, 1857, Choeradoplana Graff, 1896 e Issoca Froehlich, 1955 y se proponen enmiendas a las diagnosis de Choeradoplana e Issoca basadas en las diferenciaciones cefalicas.

Molecular phylogeny of Geoplaninae (Platyhelminthes) challenges current classification: proposal of taxonomic actions

Despite likely being the most diverse group within the Tricladida, the systematics of land planarians (Geoplanidae) has received minor attention. The most species‐rich ingroup, the subfamily Geoplaninae, is restricted to the Neotropics. The systematics of Geoplaninae remains uncertain. Unique features supporting the genera are scanty; moreover, parts of the known species have been poorly described, making comparative studies difficult. Likewise the evolutionary relationships among land planarians remain insufficiently understood. In the present study, a phylogenetic hypothesis for selected taxa of Geoplaninae based on the molecular data is presented and discussed in the light of morphological features. Our phylogenetic inference is based on the fragments of three nuclear regions (18S, 28S rDNA and EF‐1α) and a mitochondrial marker (cytochrome oxidase I) for which we considered three optimality criteria (parsimony, maximum likelihood and Bayesian inference). Although our data provide little support for most basal nodes, our phylogenetic trees show a number of well‐supported clades, unveiling morphologically homogeneous groups. According to these results, we propose to separate Geoplana into Barreirana (formerly considered a subgenus), Cratera gen. n., Imbira gen. n., Matuxia gen. n., Obama gen. n. and Paraba gen. n., emend the diagnoses of Barreirana, Geoplana, Notogynaphallia, Pasipha and Xerapoa and review the classification of the species within these genera. For Geoplana goetschi sensu Marcus, (1951), a new name is proposed.

Estado do conhecimento dos macroturbelários (Platyhelminthes) do Brasil

In the last decades, international efforts have increased, with the aim of acquiring greater knowledge on worldwide biodiversity and to propose adequate conservation policies. Brazil has joined in these efforts, as is shown by recent publications on the state of knowledge of several taxa of organisms. The macroturbellarians (Polycladida and Tricladida, Platyhelminthes) are part of one of the less studied faunal groups, not only in Brazil but also in other regions of the world. In the present study we inventoried the knowledge on the diversity of Brazilian macroturbellarians and make a comparison with that from the rest of the world. We also analyze the accomplishments of Brazilian taxonomists dealing with macroturbellarians, with regard to the world context. Our results show that almost all of the 246 described species are from the South-eastern and Southern regions. The number of species will increase significantly when new samples are undertaken in biomes and regions still little or non-sampled, as well as in already explored areas. Brazil is relatively well provided with specialists in relation to other countries. Nonetheless, in view of the high numbers of estimated diversity, new samples should concur with the academic formation of new taxonomists.

Two new species of Geoplanidae (Platyhelminthes, Tricladida, Terricola) of south Brazil

Two new species of terrestrial planarians in the family Geoplanidae, Geoplana franciscana and Notogynaphallia guaiana, from the State of Rio Grande do Sul, Brazil, are described. Both species have a multilayered lining in the female atrium. The study of specimens of N. goetschi, aimed at comparing it to N. guaiana, reveals the need for a re-description and review of N. goetschi.

A new species of terrestrial planarian (Platyhelminthes: Tricladida: Terricola) from South Brazil

Geoplana josefi sp. nov. of South Brazil is described herein. The species shows etary polymorphism. Neither youngs nor adults show the characteristic colour pattern of the mature worms. The species has a multilayered lining in the female atrium. The allopatric G. trigueira, which does not have such a lining, is similar externally and internally with adults of G. josefi, its seminal vesicle, however, being unpaired.

Insights into the origin and distribution of biodiversity in the Brazilian Atlantic forest hot spot: a statistical phylogeographic study using a low-dispersal organism.

The relative importance of the processes that generate and maintain biodiversity is a major and controversial topic in evolutionary biology with large implications for conservation management. The Atlantic Forest of Brazil, one of the world’s richest biodiversity hot spots, is severely damaged by human activities. To formulate an efficient conservation policy, a good understanding of spatial and temporal biodiversity patterns and their underlying evolutionary mechanisms is required. With this aim, we performed a comprehensive phylogeographic study using a low-dispersal organism, the land planarian species Cephaloflexa bergi (Platyhelminthes, Tricladida). Analysing multi-locus DNA sequence variation under the Approximate Bayesian Computation framework, we evaluated two scenarios proposed to explain the diversity of Southern Atlantic Forest (SAF) region. We found that most sampled localities harbour high levels of genetic diversity, with lineages sharing common ancestors that predate the Pleistocene. Remarkably, we detected the molecular hallmark of the isolation-by-distance effect and little evidence of a recent colonization of SAF localities; nevertheless, some populations might result from very recent secondary contacts. We conclude that extant SAF biodiversity originated and has been shaped by complex interactions between ancient geological events and more recent evolutionary processes, whereas Pleistocene climate changes had a minor influence in generating present-day diversity. We also demonstrate that land planarians are an advantageous biological model for making phylogeographic and, particularly, fine-scale evolutionary inferences, and propose appropriate conservation policies.

Non-destructive imaging to describe a new species of Obama land planarian (Platyhelminthes, Tricladida)

The land planarians in the genus Obama include the largest species of the Neotropical Geoplaninae. Morphological discrimination of Obama species can be difficult, as many species are morphologically similar and some present asymmetric – difficult to interpret – copulatory organs. New techniques are thus welcomed to provide faster species description and identification. Here, we study several specimens of Obama by means of mainly 2D and 3D μCT‐based images obtained through X‐ray microcomputed tomography (μCT) of a paratype, and, complementarily, histological sections of the holotype and a second paratype, which were digitized into virtual slides. Comparison of these images with traditional histological sections and descriptions of the known species of the genus allows us to conclude that our specimens constitute a new species, which we describe here. We further evaluate the phylogenetic placement of the new species using gene fragments from the mitochondrial cytochrome c oxidase subunit I and the nuclear elongation factor‐1α. Raw and derivative μCT data and virtual histological sections were deposited in an open repository (GigaDB) and are freely available. This work leads us to conclude that μCT constitutes a relatively fast, inexpensive non‐destructive method that produces results comparable to those of traditional histology, and is thus amenable for describing flatworm species.