•First records of Solenogastres from the hadal zone (>6000 m).•First phylogeny of Northwest Pacific Solenogastres reveals conflict with traditional taxonomy.•Little faunal overlap between ...investigated regions and depth zones.•Bathymetric range of >6000 m in an Acanthomeniidae species (bathyal to hadal depths).•Molecular evidence for dispersal between landward and seaward side of the Kuril-Kamchatka Trench.
Solenogastres (Mollusca, Aplacophora) form a common part of the benthic malacofauna in the deep sea, but their diversity in the Northwest Pacific is poorly understood. In this study, we analyze the systematics and distribution of Solenogastres sampled during the Kuril-Kamchatka Biodiversity Studies II expedition to the hadal Kuril-Kamchatka Trench, in the framework of previous expeditions to the shallow bathyal areas of the Japanese coast, the abyssal Kuril Basin in the Sea of Okhotsk, and the open abyssal plain of the Northwest Pacific. This unique dataset from adjacent regions extending from bathyal to hadal zones, enables us to study bathymetric and geographic distribution ranges in this neglected deep-sea clade for the first time. Our applied species delineation in these taxonomically challenging aplacophoran molluscs relies on an integrative approach, combining scleritome characters with molecular analyses. A first molecular phylogenetic study based on two mitochondrial markers reveals conflict with traditional systematics and suggests the need to revise at least two polyphyletic families and the polyphyletic order ‘Cavibelonia’. In total, 192 specimens could be grouped within 60 candidate species, which present a surprisingly rich abyssal fauna and includes the first representatives of Solenogastres at hadal depths. We found a high proportion of singletons and little faunal overlap between the investigated regions and depths, suggesting that the diversity of the abyssal and hadal Solenogastres is not entirely determined by source-sink dynamics from the bathyal slope. Rather, there is evidence for abyssal source populations, supporting the presence of endemic abyssal and potentially even hadal species. Our molecular data reject the Kuril-Kamchatka Trench as an insurmountable barrier of dispersal for Solenogastres, with one species present at both sides of the trench. Remarkably, one species from the Kuril-Kamchatka Trench shows a vertical distribution extending over more than 6,000 m. Overall, our study more than doubles the global number of solenogaster species from abyssal depths, provides first records of a unique hadal solenogaster fauna and delivers valuable insights into distribution ranges of these deep-sea molluscs.
Gastropods are among the most diverse animal clades, and have successfully colonized special habitats such as the marine sand interstitial. Specialized meiofaunal snails and slugs are tiny and ...worm-shaped. They combine regressive features - argued to be due to progenetic tendencies - with convergent adaptations. Microscopic size and concerted convergences make morphological examination non-trivial and hamper phylogenetic reconstructions. The enigmatic turbellarian-like Rhodopemorpha are a small group that has puzzled systematists for over a century. A preliminary molecular framework places the group far closer to the root of Heterobranchia - one of the major gastropod groups - than previously suggested. The poorly known meiofaunal Helminthope psammobionta Salvini-Plawen, 1991 from Bermuda is the most worm-shaped free-living gastropod and shows apparently aberrant aspects of anatomy. Its study may give important clues to understand the evolution of rhodopemorphs among basal heterobranchs versus their previously thought origin among 'higher' euthyneuran taxa.
We describe the 3D-microanatomy of H. psammobionta using three-dimensional digital reconstruction based on serial semithin histological sections. The new dataset expands upon the original description and corrects several aspects. Helminthope shows a set of typical adaptations and regressive characters present in other mesopsammic slugs (called 'meiofaunal syndrome' herein). The taxonomically important presence of five separate visceral loop ganglia is confirmed, but considerable further detail of the complex nervous system are corrected and revealed. The digestive and reproductive systems are simple and modified to the thread-like morphology of the animal; the anus is far posterior. There is no heart; the kidney resembles a protonephridium. Data on all organ systems are compiled and compared to Rhodope.
Helminthope is related to Rhodope sharing unique apomorphies. We argue that the peculiar kidney, configuration of the visceral loop and simplicity or lack of other organs in Rhodopemorpha are results of progenesis. The posterior shift of the anus in Helminthope is interpreted as a peramorphy, i.e. hypertrophy of body length early in ontogeny. Our review of morphological and molecular evidence is consistent with an origin of Rhodopemorpha slugs among shelled 'lower Heterobranchia'. Previously thought shared 'diagnostic' features such as five visceral ganglia are either plesiomorphic or convergent, while euthyneury and a double-rooted cerebral nerve likely evolved independently in Rhodopemorpha and Euthyneura.
Determining the size of the German insect fauna requires better knowledge of several megadiverse families of Diptera and Hymenoptera that are taxonomically challenging. This study takes the first ...step in assessing these "dark taxa" families and provides species estimates for four challenging groups of Diptera (Cecidomyiidae, Chironomidae, Phoridae, and Sciaridae). These estimates are based on more than 48,000 DNA barcodes (COI) from Diptera collected by Malaise traps that were deployed in southern Germany. We assessed the fraction of German species belonging to 11 fly families with well-studied taxonomy in these samples. The resultant ratios were then used to estimate the species richness of the four "dark taxa" families (DT families hereafter). Our results suggest a surprisingly high proportion of undetected biodiversity in a supposedly well-investigated country: at least 1800-2200 species await discovery in Germany in these four families. As this estimate is based on collections from one region of Germany, the species count will likely increase with expanded geographic sampling.
 This contribution is an update to the 2014 compilation of all supra- and (infra-) specific taxa of extant and fossil Valvatidae, a group of freshwater operculate snails near the base of ...Heterobranchia with a nearly worldwide distribution. This update includes corrections and many additions (two replacement taxon names, 21 mainly fossil taxa previously overlooked, and 37 invalid names) to the 2014 contribution and adds all newly described species (11) during the past eight years. The extensive reference list is directly linked, where possible, to the available electronic source of the cited papers. Keywords: freshwater snails, Gastropoda , taxonomy, Valvatidae
Biodiversity patterns are inherently complex and difficult to comprehensively assess. Yet, deciphering shifts in species composition through time and space are crucial for efficient and successful ...management of ecosystem services, as well as for predicting change. To better understand species diversity patterns, Germany participated in the Global Malaise Trap Program, a world-wide collection program for arthropods using this sampling method followed by their DNA barcode analysis. Traps were deployed at two localities: "Nationalpark Bayerischer Wald" in Bavaria, the largest terrestrial Natura 2000 area in Germany, and the nature conservation area Landskrone, an EU habitats directive site in the Rhine Valley. Arthropods were collected from May to September to track shifts in the taxonomic composition and temporal succession at these locations.
In total, 37,274 specimens were sorted and DNA barcoded, resulting in 5,301 different genetic clusters (BINs, Barcode Index Numbers, proxy for species) with just 7.6% of their BINs shared. Accumulation curves for the BIN count versus the number of specimens analyzed suggest that about 63% of the potential diversity at these sites was recovered with this single season of sampling. Diversity at both sites rose from May (496 & 565 BINs) to July (1,236 & 1,522 BINs) before decreasing in September (572 & 504 BINs). Unambiguous species names were assigned to 35% of the BINs (1,868) which represented 12,640 specimens. Another 7% of the BINs (386) with 1,988 specimens were assigned to genus, while 26% (1,390) with 12,092 specimens were only placed to a family. These results illustrate how a comprehensive DNA barcode reference library can identify unknown specimens, but also reveal how this potential is constrained by gaps in the quantity and quality of records in BOLD, especially for Hymenoptera and Diptera. As voucher specimens are available for morphological study, we invite taxonomic experts to assist in the identification of unnamed BINs.
Molluscs Haszprunar, Gerhard; Wanninger, Andreas
Current biology,
07/2012, Letnik:
22, Številka:
13
Journal Article
Recenzirano
Odprti dostop
People often associate the animal phylum ‘Mollusca’ with their most species-rich or popular subgroups: gastropods (snails, whelks, slugs, and limpets), bivalves (mussels and clams), and cephalopods ...(the pearl boat Nautilus, sepias, squids and octopuses, and the many fossil ammonites and belemnites). Of these, the gastropods, with more than 100,000 extant species, comprise about 80% of all molluscs and are by far the most diverse group within the phylum. The remaining classes, the aplacophoran Solenogastres (or Neomeniomorpha) and Caudofoveata (or Chaetodermomorpha), the Polyplacophora (chitons), Monoplacophora (or Tryblidia or Tergomya), and Scaphopoda (tusk-shells), are known to a much lesser extent (Box 1), but add significantly to the variability of the molluscan bauplan and to our understanding of molluscan phylogeny and evolution.
Substantial parts of the European and German insect fauna still remain largely unexplored, the so-called "dark taxa". In particular, midges (Diptera) and parasitoid wasps (Hymenoptera) are abundant ...and species-rich throughout Europe, yet are often neglected in biodiversity research. One such dark taxon is Microgastrinae wasps (Hymenoptera: Braconidae), a group of parasitoids of lepidopteran caterpillars with 252 species reported in Germany so far. As part of the German Barcode of Life Project GBOL III: Dark Taxa, reverse DNA barcoding and integrative taxonomic approaches were used to shed some light on the German Fauna of Microgastrinae wasps. In our workflow, DNA barcoding was used for molecular clustering of our specimens in a first step, morphological examination of the voucher specimens in a second step, and host data compared in a third step. Here, 30 species are reported for the first time in Germany, adding more than 10% to the known German fauna. Information for four species is provided in a new Holarctic context, reporting them for the Nearctic or, respectively, Palaearctic region, and 26 additional country records are added from sequenced material available in the collections accessible to us. Molecular clusters that show signs of discrepancies are discussed. Results show that we are just scratching the tip of the iceberg of the unexplored Microgastrinae diversity in Germany.
The Lepetelloidea, a clade of small limpet‐shaped gastropods, can be used as a case study in continental margin and deep‐sea diversification. Lineages in this clade have been found associated with a ...combination of different substrates, including hydrothermal vents, seeps, wood, whale carcasses, polychaete tubes, chondrichthyan egg cases, seagrass rhizomes, algal holdfasts, crab carapaces, and sponges. Members of one lepetelloidean family, Lepetellidae, live on or inside empty tubes of members of the polychaete genus Hyalinoecia. The detailed morphology of a Mediterranean species, Lepetella sierrai Dantart & Luque 1944, was reconstructed in three dimensions from serial semi‐thin sections and compared with that of eleven other members of Lepetellidae. The hermaphroditic lepetellid limpets possessed a ciliated seminal groove, distinct testis and ovary with a common distal gonoduct, and a seminal receptacle containing mature sperm. A unique alimentary tract, with huge esophageal pouches, no true stomach, an extensive multilobed midgut, and short intestine, was present. Additionally, a bacteriocyte system throughout the entire mantle rim was revealed via light and transmission electron microscopy. This is the first recognized evidence for intracellular microbial symbiosis in lepetelloidean limpets. Semi‐thin sections showed evidence of a parasite, potentially a chitonophilid copepod, penetrating the body wall of the limpet. Hypotheses about reproductive biology, feeding, and symbiosis are presented based on anatomical features and knowledge of the habitat described herein.
Solenogastres (Mollusca) have a quite uniform bodyplan and an evolutionary history with few shifts out of their deep-water habitat and beyond their epibenthic lifestyle. Consequently, few clades ...inhabit the shallow subtidal mesopsammon; only Meiomeniidae (order Pholidoskepia) is entirely restricted to this habitat. What was initially designed as a comparative microanatomical redescription of Meiomeniidae to explore the diversity of this clade with its unique evolution, developed into a taxonomic nightmare of cryptic, co-occurring lineages: three out of four valid species of Meiomeniidae co-occur in coarse sands in the Bermuda archipelago and were re-collected at the respective type localities. We analyzed the material combining three-dimensional (3D) reconstructions from histological serial sections and ultrastructural data, providing novel insights into meiomeniid anatomy and discussing potential phylogenetic implications. However, not all collected material could be unambiguously assigned to known lineages of mesopsammic Solenogastres. In addition to meiomeniids, we discovered another co-occurring, externally highly cryptic but anatomically distinguishable lineage. It is provisionally placed within Dondersiidae, but its taxonomic assignment remains problematic due to an exclusive character mosaic and a unique foregut gland complex. Our study reveals the risk of creating chimeric taxa in small-bodied Solenogastres, as morphological characters needed for species delineation cannot be extracted from single individuals, while conspecifity based on external features is risky to assume with cryptic species co-occurring. Molecular markers will be needed to reliably retrieve Meiomeniidae from their current Bermuda Triangle of taxonomy and to proceed in solenogaster taxonomy confronted with a wealth of poorly known lineages especially in meiofaunal forms.
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