RESUMEN
We present a DNA barcoding study on the insect order Orthoptera that was generated in collaboration between four barcoding projects in three countries, viz. Barcoding Fauna Bavarica (Germany), German Barcode of Life, Austrian Barcode of Life and Swiss Barcode of Life. Our data set includes 748 COI sequences from 127 of the 162 taxa (78.4%) recorded in the three countries involved. Ninety-three of these 122 species (76.2%, including all Ensifera) can be reliably identified using DNA barcodes. The remaining 26 caeliferan species (families Acrididae and Tetrigidae) form ten clusters that share barcodes among up to five species, in three cases even across different genera, and in six cases even sharing individual barcodes. We discuss incomplete lineage sorting and hybridization as most likely causes of this phenomenon, as the species concerned are phylogenetically young and hybridization has been previously observed. We also highlight the problem of nuclear mitochondrial pseudogenes (numts), a known problem in the barcoding of orthopteran species, and the possibility of Wolbachia infections. Finally, we discuss the possible taxonomic implications of our barcoding results and point out future research directions.
Asunto(s)
Código de Barras del ADN Taxonómico , Ortópteros/clasificación , Ortópteros/genética , Animales , Austria , ADN Bacteriano/genética , Complejo IV de Transporte de Electrones/genética , Alemania , Cooperación Internacional , Suiza , Wolbachia/genéticaRESUMEN
Biodiversity loss is mainly driven by human activity. While concern grows over the fate of hot spots of biodiversity, contemporary species losses still prevail in industrialized nations. Therefore, strategies were formulated to halt or reverse the loss, driven by evidence for its value for ecosystem services. Maintenance of the latter through conservation depends on correctly identified species. To this aim, the German Federal Ministry of Education and Research is funding the GBOL project, a consortium of natural history collections, botanic gardens, and universities working on a barcode reference database for the country's fauna and flora. Several noticeable findings could be useful for future campaigns: (i) validating taxon lists to serve as a taxonomic backbone is time-consuming, but without alternative; (ii) offering financial incentives to taxonomic experts, often citizen scientists, is indispensable; (iii) completion of the libraries for widespread species enables analyses of environmental samples, but the process may not hold pace with technological advancements; (iv) discoveries of new species are among the best stories for the media; (v) a commitment to common data standards and repositories is needed, as well as transboundary cooperation between nations; (vi) after validation, all data should be published online via the BOLD to make them searchable for external users and to allow cross-checking with data from other countries.
Asunto(s)
Biodiversidad , Código de Barras del ADN Taxonómico , Bases de Datos Genéticas , Animales , Países Desarrollados , Alemania , Adhesión a Directriz , Humanos , Cooperación Internacional , Bibliotecas , Reproducibilidad de los ResultadosRESUMEN
We present the first comprehensive DNA barcoding study of German reptiles and amphibians representing likewise the first on the European herpetofauna. A total of 248 barcodes for all native species and subspecies in the country and a few additional taxa were obtained in the framework of the projects 'Barcoding Fauna Bavarica' (BFB) and 'German Barcode of Life' (GBOL). In contrast to many invertebrate groups, the success rate of the identification of mitochondrial lineages representing species via DNA barcode was almost 100% because no cases of Barcode Index Number (BIN) sharing were detected within German native reptiles and amphibians. However, as expected, a reliable identification of the hybridogenetic species complex in the frog genus Pelophylax was not possible. Deep conspecific lineages resulting in the identification of more than one BIN were found in Lissotriton vulgaris, Natrix natrix and the hybridogenetic Pelophylax complex. A high variety of lineages with different BINs was also found in the barcodes of wall lizards (Podarcis muralis), confirming the existence of many introduced lineages and the frequent occurrence of multiple introductions. Besides the reliable species identification of all life stages and even of tissue remains, our study highlights other potential applications of DNA barcoding concerning German amphibians and reptiles, such as the detection of allochthonous lineages, monitoring of gene flow and also noninvasive sampling via environmental DNA. DNA barcoding based on COI has now proven to be a reliable and efficient tool for studying most amphibians and reptiles as it is already for many other organism groups in zoology.
Asunto(s)
Anfibios/clasificación , ADN/genética , Reptiles/clasificación , Anfibios/genética , Animales , Biodiversidad , Código de Barras del ADN Taxonómico , Alemania , Filogenia , Reptiles/genéticaRESUMEN
The microanatomy and ultrastructure of the excretory system of an undescribed mesopsammic gastropod of the genus Hedylopsis have been examined by means of semithin serial sections, reconstructions, and transmission electron microscopy. The functional metanephridial system comprises a monotocardian heart with a single ventricle and auricle in a spacious pericardium as well as a single, large kidney. Podocytes in the auricular epicardium represent the site of ultrafiltration and formation of the primary urine, whereas the flat epithelium of the kidney with extensive basal infoldings, large vacuoles and the apical microvillous border indicates modification of the primary filtrate. Solitary rhogocytes (pore cells) represent additional loci of ultrafiltration with an identical fine-structure as those of the podocytes (meandering slits with diaphragms covered by extracellular matrix). The presence of podocytes situated in the epicardial wall of the auricle is regarded as plesiomorphic for the Opisthobranchia and is confirmed for the Acochlidia for the first time. Kidney and rectum both open into a small, yet distinct mantle cavity. Within the Acochlidia this condition represents a plesiomorphic character only known from one further Hedylopsis species until now. Special cells (here termed microvillous pit-cells) with a presumed absorptive function are interspersed between the epithelial cells of the mantle cavity. They are mainly characterized by a prominent invagination of the apical border with densely arranged, very large microvilli. The presence of a mantle cavity that has been lost in all other acochlidian genera supports the systematic placement of the Hedylopsidae at the base of the Achochlidia.
RESUMEN
This study presents the first detailed account of the larval and early post-metamorphic development of a scaphopod species, Antalis entalis, since 1883. Special reference is given to the expression pattern of an engrailed protein during the formation of the embryonic (protoconch) and adult shell (teleoconch). We found that in the trochophore-like larva the engrailed protein is expressed in shell-secreting cells at the margin of the protoconch close to the mantle edge. During metamorphosis the growth of the protoconch and expression of the engrailed protein along its margin stop and the teleoconch starts to form. These data suggest a different genetic background regarding protoconch and teleoconch formation in the Scaphopoda and possibly all Conchifera, thus inferring a different evolutionary origin of both organs. The single anlage of the scaphopod protoconch contradicts earlier hypotheses of a monophyletic taxon Diasoma (Scaphopoda + Bivalvia), which has been mainly based on the assumption of a primarily bilobed shell in both taxa. Comparative data on engrailed expression patterns suggest nervous system patterning as the basic function of engrailedin the Bilateria. However, there are several independent gain-of-function events, namely segment compartmentation in the Annelida and Arthropoda, protoconch formation in the Mollusca, skeletogenesis in the Echinodermata, and limb formation in vertebrates. These findings provide further evidence that homologous genes may act in very different pathways of bilaterian body plan formation in various animal phyla.
Asunto(s)
Proteínas de Homeodominio/metabolismo , Moluscos/crecimiento & desarrollo , Animales , Evolución Biológica , Regulación del Desarrollo de la Expresión Génica , Larva/crecimiento & desarrollo , Larva/metabolismo , Larva/ultraestructura , Microscopía Electrónica de Rastreo , Microscopía Fluorescente , Moluscos/metabolismo , Moluscos/ultraestructuraRESUMEN
The microanatomy and ultrastructure of the excretory system of Pneumoderma sp. (Gymnosomata) and Creseis virgula Rang, 1828 (Thecosomata) have been investigated by means of semithin serial sections, reconstructions and transmission electron microscopy. The studies revealed a functional metanephridial system consisting of a heart with a single ventricle and auricle in a pericardial cavity and a single kidney in both species. Podocytes in the atrial wall of the pericardial epithelium are the site of ultrafiltration, whereas the flat epithelium of the kidney with numerous basal infoldings and a dense microvillous border on the luminal surface suggests modification of the ultrafiltrate. In Pneumoderma sp., additional loci of ultrafiltration with identical fine structure (meandering slits with diaphragms covered by extracellular matrix) occur in the solitary rhogocytes (pore cells). The presence of podocytes situated on the atrial wall in representatives of two higher opisthobranch taxa contradicts former ideas on the loss of the primary site of ultrafiltration in the ancestors of the Opisthobranchia.
Asunto(s)
Células Epiteliales/ultraestructura , Moluscos/ultraestructura , Animales , Riñón/ultraestructura , Microscopía Electrónica , Pericardio/ultraestructuraRESUMEN
The microanatomy and ultrastructure of the larval excretory system of Patella vulgata L., 1758 has been examined by means of semithin and ultrathin serial sections, reconstructions, and transmission electron microscopy. The protonephridial system appears after torsion and consists of two terminal flame bulbs with narrow, ciliated ducts. Whereas the polyciliary terminal cells (cyrtocytes) are only slightly asymmetrically placed below the mantle cavity, the distal excretory ducts and their openings show remarkable asymmetry due to torsion. Further larval ultrafiltration sites with identical fine-structure (meandering slits with diaphragms covered by extracellular matrix) are present in the solitary rhogocytes (pore cells). The presence of larval protonephridia is regarded as plesiomorphic for Mollusca and the Trochozoa (Spiralia) as a whole and the specific conditions (asymmetry, simplicity) in Patella are probably plesiomorphic for the Gastropoda.
Asunto(s)
Moluscos/ultraestructura , Animales , Riñón/ultraestructura , Larva/ultraestructura , Moluscos/clasificaciónRESUMEN
Whole-mount technique using fluorescent-labelled phalloidin for actin staining and confocal laser scanning microscopy as well as semi-thin serial sectioning, scanning and transmission electron microscopy were applied to investigate the ontogeny of the various muscular systems during larval development in the limpets Patella vulgata L. and P. caerulea L. In contrast to earlier studies, which described a single or two larval shell muscles, the pretorsional trochophore-like larva shows no less than four different muscle systems, namely the asymmetrical main head/foot larval retractor muscle, an accessory larval retractor with distinct insertion area, a circular prototroch/velar system, and a plexus-like pedal muscle system. In both Patella species only posttorsional larvae are able to retract into the shell and to close the aperture by means of the operculum. Shortly after torsion the two adult shell muscles originate independently in lateral positions, starting with two fine muscle fibres which insert at the operculum and laterally at the shell. During late larval development the main larval retractor and the accessory larval retractor become reduced and the velar muscle system is shed. In contrast, the paired adult shell muscles and the pedal muscle plexus increase in volume, and a new mantle musculature, the tentacular muscle system, and the buccal musculature arise. Because the adult shell muscles are entirely independent from the various larval muscular systems, several current hypotheses on the ontogeny and phylogeny of the early gastropod muscle system have to be reconsidered.
Asunto(s)
Moluscos/embriología , Músculos/anatomía & histología , Animales , Larva/anatomía & histología , Larva/crecimiento & desarrollo , Larva/ultraestructura , Microscopía Electrónica de Rastreo , Microscopía Fluorescente , Músculos/embriología , Músculos/ultraestructuraRESUMEN
"Remane-Hennigian systematists" still reject parsimony analysis for phylogenetics, because homology or apomorphy analyses are not included. In contrast, "pattern cladists" regard homology as a deductive concept after applying a parsimony test of character congruence. However, as in molecular phylogeny, selection of "good" characters is always done on the basis of an a priori homology analysis. The distribution criterion of homology-"homologous characters have identical or hierarchical distribution"-is the basis of parsimony analysis. Because this criterion also might fail in cases of genealogical reticulation or concerted homoplasy, character congruence is not a strict test but another probabilistic criterion of homology. A synthetic approach is proposed for phenotypic analysis with application of a priori criteria of homology. The resulting a priori probabilities of homology serve as criteria for selection and weighting of characters (very low = not selected/poor/mediocre/good/Dollo characters). After application of a parsimony algorithm the final cladogram decides homology estimations.
Asunto(s)
Evolución Molecular , Modelos Biológicos , Filogenia , Algoritmos , Modelos Genéticos , Modelos EstadísticosRESUMEN
The aesthetes of Leptochiton algesirensis (Capellini, 1859) and Leptochiton cancellatus (Sowerby, 1840) consist of six to eight microaesthetes surrounding one macroaesthete. The monocellular microaesthetes include many microtubules, neurosecretory vesicles, and unperforated, subsidiary caps. Basally they are in contact with tiny nerve processes via probably electrical synapses. Each macroaesthete consists of a perforated apical cap and various cell types: flattened peripheral cells, various types of mucous cells, and three or four monociliary sensory cells. Although lacking photoreceptors, the aesthetes of Leptochiton algesirensis combine storage-secretory and sensory functions. The latter function is confirmed by positive immunoreactions against (neuro-)tubulin and synaptophysine. The high degree of structural and functional similarity between polyplacophoran aesthetes and the analogous caeca of brachiopods is demonstrated.
Asunto(s)
Moluscos/química , Moluscos/ultraestructura , Animales , Ojo/química , Ojo/ultraestructura , FMRFamida , Inmunohistoquímica , Hormonas de Invertebrados/química , Neuropéptidos/química , Serotonina/química , Sinaptofisina/química , Tubulina (Proteína)/químicaRESUMEN
The larger gastropod taxa are characterized by distinctive cleavage patterns. The cell stage at which the mesentoblast is formed appears to be crucial. In none of the taxa is it formed earlier than the 24- and not later than the 63-cell stage. A heterochronic shift from late to early mesentoblast formation appears to coincide with successive steps in gastropod evolution. Comparison of the early cleavage patterns appears to be a powerful method for investigating the evolutionary relations between major gastropod taxa.