Terminal Lobes Research Articles

Morphological and molecular characterization of Glossidium pedatum Looss, 1899 and Orientocreadium batrachoides Tubangui, 1931 from sharptooth catfish, Clarias gariepinus (Burchell, 1822)

The superfamily Plagiorchioidea has a considerable number of genera and species with great uncertainty of their phylogenetic position. The objectives of the current study were to specifically describe the morphology and determine for the first time the phylogenetic position of Glossidium pedatum and Orientocreadium batrachoides. Examination of G. pedatum using conventional light and scanning microscopy techniques revealed undescribed features related to the digestive system, the presence of papillae-like lateral lappets, and terminal lobes covered with backwardly directed spines. Orientocreadium batrachoides revealed a pharynx that is four lobed anteriorly. Both the large (28S) and small (18S) subunits of the ribosomal genome, analysed through Bayesian inference and maximum likelihood, were used to genetically characterise these species. Phylogenies indicate that G. pedatum does not fit well into any known family within the Plagiorchioidea, as currently indicated in various systematic structures based on morphology. However, G. pedatum was closely related to Haematoloechidae according to analyses of 18S and 28S rDNA. Based on 28S rDNA, O. batrachoides formed a well-supported clade with Orientocreadium pseudobagri within the family Orientocreadiidae. In turn, Orientocreadiidae is closely related to Leptophallidae. The current study provides essential information that could be helpful to assign the family for Glossidium in future studies. Characterisation of life-cycle stages may be necessary to fully elucidate the systematic position of G. pedatum.

Daily bathymetric surveys document how stratigraphy is built and its extreme incompleteness in submarine channels

Turbidity currents are powerful flows of sediment that pose a hazard to critical seafloor infrastructure and transport globally important amounts of sediment to the deep sea. Due to challenges of direct monitoring, we typically rely on their deposits to reconstruct past turbidity currents. Understanding these flows is complicated because successive flows can rework or erase previous deposits. Hence, depositional environments dominated by turbidity currents, such as submarine channels, only partially record their deposits. But precisely how incomplete these deposits are, is unclear. Here we use the most extensive repeat bathymetric mapping yet of any turbidity current system, to reveal the stratigraphic evolution of three submarine channels. We re-analyze 93 daily repeat surveys performed over four months at the Squamish submarine delta, British Columbia in 2011, during which time >100 turbidity currents were monitored. Turbidity currents deposit and rework sediments into upstream-migrating bedforms, ensuring low rates of preservation (median 11%), even on the terminal lobes. Large delta-lip collapses (up to 150,000 m3) are relatively well preserved, however, due to their rapidly emplaced volumes, which shield underlying channel deposits from erosion over the surveyed timescale. The biggest gaps in the depositional record relate to infrequent powerful flows that cause significant erosion, particularly at the channel-lobe transition zone where no deposits during our monitoring period are preserved. Our analysis of repeat surveys demonstrates how incomplete the stratigraphy of submarine channels can be, even over just 4 months, and provides a new approach to better understand how the stratigraphic record is built and preserved in a wider range of marine settings.

Ice Thickness Estimation from Geophysical Investigations on the Terminal Lobes of Belvedere Glacier (NW Italian Alps)

: Alpine glaciers are key components of local and regional hydrogeological cycles and real-time indicators of climate change. Volume variations are primary targets of investigation for the understanding of ongoing modifications and the forecast of possible future scenarios. These fluctuations can be traced from time-lapse monitoring of the glacier topography. A detailed reconstruction of the ice bottom morphology is however needed to provide total volume and reliable mass balance estimations. Non-destructive geophysical techniques can support these investigations. With the aim of characterizing ice bottom depth, ground-penetrating radar (GPR) profiles and single-station passive seismic measurements were acquired on the terminal lobes of Belvedere Glacier (NW Italian Alps). The glacier is covered by blocks and debris and its rough topography is rapidly evolving in last years, with opening and relocation of crevasses and diffuse instabilities in the frontal sectors. Despite the challenging working environment, ground-based GPR surveys were performed in the period 2016–2018, using 70-MHz and 40-MHz antennas. The 3D ice bottom morphology was reconstructed for both frontal lobes and a detailed ice thickness map was obtained. GPR results also suggested some information on ice bottom properties. The glacier was found to probably lay on a thick sequence (more than 40 m) of subglacial deposits, rather than on stiff bedrock. Week deeper reflectors were identified only in the frontal portion of the northern lobe. These interfaces may indicate the bedrock presence at a depth of around 80 m from the topographic surface, rapidly deepening upstream. Single-station passive seismic measurements, processed with the horizontal-to-vertical spectral ratio (HVSR) method, pointed out the absence of sharp vertical contrast in acoustic impedance between ice and bottom materials, globally confirming the hypotheses made on GPR results. The obtained results have been compared with previous independent geophysical investigations, performed in 1961 and 1985, with the same aim of ice thickness estimation. The comparison allowed us to validate the results obtained in the different surveys, supply a reference base map for the glacier bottom morphology and potentially study ice thickness variations over time.

Late Quaternary geomorphology and sedimentary processes in the Zambezi turbidite system (Mozambique Channel)

The morphology and present-day sediment distribution of the Zambezi turbidite system was investigated using new bathymetric and sub-bottom profiler data as part of the PAMELA research project. The Zambezi turbidite system is composed of two depositional systems: a channelized fan (the Zambezi Fan) and a semi-confined fan (in the lntermediate Basin). The Zambezi Fan includes the Zambezi Valley, which is deeply incised in the Mozambique Channel and is more than three times as large and deep as the great Tanzanian and North Atlantic Mid-Ocean channels. The erosion in the Zambezi Valley is evidenced by its V-shaped morphology and the existence of a U-shaped thalweg affected by several generations of incisions. Based on echo facies and cores from literature, sediments of the Zambezi Fan are dominantly coarse-grained and fine-grained overbank deposits are infrequent. The distal portion of the Zambezi Fan is a main depositional area where typical transparent wedged-shape seismic bodies are interpreted as terminal lobes. Seismic facies in the Intermediate Basin are thought to represent mostly fine-grained turbidites intercalated with infrequent coarse-grained sheet-like turbidites. Hydrodynamic circulation (from surface eddies to the deep circulation of NADW) appears to have a great impact on the Mozambique Channel sedimentation and is suggested (1) to be involved in the delivery of the Zambezi River sediments along the Mozambique margin, (2) to entrain the upper suspended load of turbidity currents, contributing to the absence of fine-grained sedimentation and (3) to contribute to the erosion of the valley flanks leading to the exceptionally great dimensions of the valley.

A database solution for the quantitative characterisation and comparison of deep-marine siliciclastic depositional systems

Abstract Comparative analyses of deep-marine sedimentological studies are hindered by the wide variety in methods of data collection, scales of observation, resolution, classification approaches and terminology. A relational database, the Deep-Marine Architecture Knowledge Store (DMAKS), has been developed to facilitate such analyses, through the integration of deep-marine sedimentological data collated to a common standard. DMAKS hosts data on siliciclastic deep-marine system boundary conditions, and on architectural and facies properties, including spatial, temporal and hierarchical relationships between units at multiple scales. DMAKS has been devised to include original and literature-derived data from studies of the modern sea-floor, and from ancient successions studied in the subsurface and in outcrop. The database can be used as a research tool in both pure and applied science, allowing the quantitative characterisation of deep-marine systems. The ability to synthesise data from several case studies and to filter outputs on multiple parameters that describe the depositional systems and their controlling factors enables evaluation of the degree to which certain controls affect sedimentary architectures, thereby testing the validity of existing models. In applied contexts, DMAKS aids the selection and application of geological analogues to hydrocarbon reservoirs, and permits the development of predictive models of reservoir characteristics that account for geological uncertainty. To demonstrate the breadth of research applications, example outputs are presented on: (i) the characterisation of channel geometries, (ii) the hierarchical organisation of channelised and terminal deposits, (iii) temporal trends in the deposition of terminal lobes, (iv) scaling relationships between adjacent channel and levee architectural elements, (v) quantification of the likely occurrence of elements of different types as a function of the lateral distance away from an element of known type, (vi) proportions and transition statistics of facies in elements and beds, (vii) variability in net-to-gross ratios among element types.

Two new species of Elwendia (Apiaceae) from Uzbekistan

Two new species of Apiaceae are described as new to science, Elwendia bucharica from the Hissar Range (Pamir-Alay) and E. ugamica from the Ugom Range (Western Tian-Shan). Both species are related to E. capusii. Elwendia bucharica is distinguished by the short terminal lobes of leaves, number of bracts, shape of pedicels, and number of secretory ducts in petals. Elwendia ugamica is distinguished by the short terminal lobes of stem leaves, terminal umbels of lateral branches, shape of stylopods, and shape of styles.

Depositional history of the western Nile Delta, Egypt: Late Rupelian to Pleistocene

The availability of onshore and offshore three-dimensional seismic surveys facilitated detailed seismic sequence-stratigraphic interpretation of a large swath of the western Nile Delta evolution since the late Oligocene. The resulting sequence-stratigraphic framework is calibrated against more than 60 wells. The interpretation of repetitive sequence boundaries, that is, unconformities, on seismic sections was constrained by high-resolution abundance and diversity within biostratigraphic data sets and lithofacies-stacking patterns interpreted from well logs. Our series of depositional facies maps reflect environments of undifferentiated lowstand and transgressive systems tracts, that is, depositional elements interpreted between the lower bounding unconformity surface (sequence boundary) and maximum flooding surface above. These typically constitute terrestrial distributary channels and floodplains landward of strike-aligned lowstand deltas and marine shoreline deposits at and over the relict shelf break area of the underlying sequence boundary. Basinward deep-marine shales, slope channels, splays, fans, and terminal channel lobes define the remainder of the deposition over the rather extensive deep-marine slope apron region of the western Nile Delta. Incised valleys, canyons, and broad slope channels often confine any of the above-mentioned depositional facies at the lower bounding unconformity of each sequence.

Neocarus spelaion sp. n. (Parasitiformes, Opilioacaridae), a new species of cave dwelling Neocarus from Minas Gerais state, Brazil

A new cave dwelling species of the genusNeocarus(Parasitiformes: Opilioacarida: Opilioacaridae) is described from adult females and males collected in Minas Gerais state, southeast Brazil. Five or sixd-type setae on palps, females with pregenital area hairless, genital setae smooth, cylindrical ovipositor with two terminal lobes, and males with genital and pregenital setae variable in shape, some being smooth and pointed, others ribbed and pointed, are the combinations of characters that define the new species.

The Tectonically Controlled San Gabriel Channel–Lobe Transition Zone, Catalina Basin, Southern California Borderland

Abstract High-resolution geophysical data across the Catalina Basin, offshore southern California, USA, reveal a complex channel–lobe transition zone (CLTZ) and provide an opportunity to characterize an entire seafloor CLTZ in a tectonically active and confined-basin setting. The seafloor morphology, distribution of depositional and erosional features, and location of depocenters in the CLTZ are controlled by shifting confinement and seafloor gradient related to inherited basement structures, active faults, and basin margins. Below a Holocene hemipelagic drape, the Catalina Basin is dominated by CLTZ and lobe sedimentation from the San Gabriel Channel, with lesser accumulations from local sediment sources limited to basin margins. The San Gabriel Channel is structurally confined as it enters the Catalina Basin and appears unable to avulse; it continues into the basin as a channel that rapidly widens, decreases in relief, and becomes scoured at its margins. A CLTZ is imaged between the confined San Gabriel channel and its terminal lobes deposited > 50 km into the basin. Narrow, apparently disconnected channels with knickpoints occur throughout the proximal and mid-CLTZ and are concentrated near basement highs and basin-bounding Quaternary-active dextral strike-slip faults. A field of small-scale erosional crescent-shaped scours (∼ 100 m length, ∼ 200 m width, up to ∼ 10 m relief across ∼ 30 km2 region) occurs above a partially buried basement high that creates perturbations in seafloor gradient. Likewise, above a buried basement structure that locally increases seafloor gradient (up to 0.4°), the distal CLTZ may contain sediment waves (∼ 2–4 m wave height and ∼ 200–300 m wavelength) that are smaller than many other CLTZ examples. This study of the San Gabriel CLTZ in Catalina Basin provides high-resolution geophysical data coverage of a complete CLTZ and illustrates a tectonically controlled end-member CLTZ from the modern seafloor.

A depositional model for deep‐lacustrine, partially confined, turbidite fans: Early Cretaceous, North Falkland Basin

AbstractThis paper presents a model of facies distribution within a set of early Cretaceous, deep‐lacustrine, partially confined turbidite fans (Sea Lion Fan, Sea Lion North Fan and Otter Fan) in the North Falkland Basin, South Atlantic. As a whole, ancient deep‐lacustrine turbidite systems are under‐represented in the literature when compared with those documented in marine basins. Lacustrine turbidite systems can form extensive, good quality hydrocarbon reservoirs, making the understanding of such systems crucial to exploration within lacustrine basins. An integrated analysis of seismic cross‐sections, seismic amplitude extraction maps and 455 m of core has enabled the identification of a series of turbidite fans. The deposits of these fans have been separated into lobe axis, lobe fringe and lobe distal fringe settings. Seismic architectures, observed in the seismic amplitude extraction maps, are interpreted to represent geologically associated heterogeneities, including: feeder systems, terminal mouth lobes, flow deflection, sinuous lobe axis deposits, flow constriction and stranded lobe fringe areas. When found in combination, these architectures suggest ‘partial confinement’ of a system, something that appears to be a key feature in the lacustrine turbidite setting of the North Falkland Basin. Partial confinement of a system occurs when depositionally generated topography controls the flow‐pathway and deposition of subsequent turbidite fan deposits. The term ‘partial confinement’ provides an expression for categorising a system whose depositional boundaries are unconfined by the margins of the basin, yet exhibit evidence of internal confinement, primarily controlled by depositional topography. Understanding the controls that dictate partial confinement; and the resultant distribution of sand‐prone facies within deep‐lacustrine turbidite fans, is important, particularly considering their recent rise as hydrocarbon reservoirs in rift and failed‐rift settings.

Gullies and debris-flows in Ladakh Himalaya, India: a potential Martian analogue

Abstract We conducted comparative morphological analysis of gullies within two high-latitude Martian craters (Domoni and Maricourt) in the northern hemisphere of Mars with (1) the debris-flow gully systems in the Ladakh Himalaya and (2) Istok Crater in the southern mid-latitudes of Mars where water-bearing debris-flow deposits have been previously reported. Our findings suggest that the debris-flow landforms preserved on gully and alluvial fans in the Ladakh Himalaya are potential analogues for the deposits preserved over the equator-facing slopes of Domoni and Maricourt Craters. Further, we found that the morphological attributes of channels and deposits (including overlapping terminal lobes, levées, tongue-shaped/lobate deposits and broad/small depositional deposits) within both the study craters and Istok Crater are similar. As a result, the studied craters emerge as additional sites in which possible evidence of water-bearing debris-flows are preserved on Mars. By comparison to our Earth analogue, we further propose that episodic melting of snow accumulated within the sheltered alcoves is the most likely source of water for the formation of such gullies. Taken together, our findings suggest that debris-flow may not be a rare process in gully formation on Mars and evidence may be preserved in other unexplored areas.

Application of spectral decomposition and neural networks to characterise deep turbidite systems in the outer fold and thrust belt of the Niger Delta

ABSTRACTWe have applied a wavelet‐based spectral decomposition scheme and a multi‐layered feed‐forward neural network to interpret turbidite depositional systems from three‐dimensional reflection seismic data and well logs for a prospective hydrocarbon zone in the outer fold and thrust belt of the Niger Delta. The goal was to overcome difficulties in interpreting depositional systems from deep sections of the Field, occasioned by loss of seismic resolution with depth and the sparse distribution of wells.The decomposition scheme allowed us to delineate multiple depositional systems not apparent on the conventional seismic amplitude display. These systems include linear channel systems with terminal splay lobes, a sinuous channel system and its abandoned meander loops, and sediment wave features in overbank areas. Delineated channel morphologies and transport directions varied both laterally and vertically and were possibly dependent upon the disposition of the pre‐thrusting paleo‐seafloor. Terminal splay lobes are fragmented and coincident with the locations of topographic lows, which are possibly related to the initial configurations of the oceanic basement below. Predicted porosity and resistivity distributions have morphologies that correlate well with the mapping provided by the spectral decomposition scheme. The property distributions indicate that reservoir prone systems in the Field and possibly within the outer fold and thrust belt are composed primarily of channel systems, both linear and sinuous, and their associated splay lobes. The channel systems appear vertically stacked, and this situation possibly increases the potential success rate for exploration wells in the region. Beyond channel limits, redistributive bottom currents varying rapidly in speed and direction apparently encouraged the dispersal of sand‐rich sediments to form sediment waves.Despite the limited well control, the methodology significantly aided our interpretation. It proved effective at revealing the distribution of reservoir prone facies within the Field and provided insight into the dominant factors that controlled deposition within the Field.

Tidal current-dominated depositional environments in the central-northern Yellow Sea as revealed by heavy-mineral and grain-size dispersals

This study confirms that the fine sand-sized detritus in the central-northern Yellow Sea is chiefly derived by the Yellow River and explains the Holocene Yellow River dispersal system and the preservation of transgressive deposits by heavy-mineral and grain-size analyses. Micas, which are sensitive to hydraulic sorting, offer an effective key for identifying the dispersal of Holocene Yellow River-derived fine-grained sediments. The heavy-mineral compositional changes are attributed to hydraulic sorting by different marine dynamics and various mixing with additional local transgressive deposits of miscellaneous provenance. The effects of hydraulic sorting are dominated by Holocene tidal currents and by foreshore waves during the rapid transgression, respectively. The former results in obvious enrichments of garnet and common stable species such as Ti oxides, tourmaline, and titanite, whereas the latter seems more remarkable for the compositional changes, with further depletion of epidote, actinolite/tremolite and zoisite/clinozoisite. The central Yellow Sea mud deposit and the alongshore muddy zone off the southern Liaodong Peninsula are opposite to each other as a pair of structurally symmetric coalesced terminal lobes far away from the high-energy strait between Cape Chengshan and Changsan-got. The Haiyang subaqueous clinoform as another terminal lobe is revealed by a heavy-mineral index, which represents an extremity of deposits accumulated by the modern Yellow River-derived sediments off the southwestern Shandong coast. A small mud patch is revealed, roughly corresponding to the central regime of the amphidromic system of principal M2 constituent. The tidal current-dominated depositional pattern proposed here emphasizes the importance of time–velocity asymmetry of tidal currents. Such a dynamic mechanism is primarily responsible for the dispersal of the modern Yellow River-derived sediments when they are entrained from the Bohai Sea to the South Yellow Sea through the Bohai Strait and the strait between Cape Chengshan and Changsan-got.

Molecular phylogeny of the genus Rhabdosciadium (Apiaceae) with description of a new species R. anatolyi from Hakkâri province, eastern Turkey

Six species of the genus Rhabdosciadium (Apiaceae) were studied by molecular phylogenetic analysis. The taxonomic status of each of them has been confirmed, the genus Rhabdosciadium turns out as a well-supported monophyletic group closely related to the genera Aegopodium, Caropodium, Carum, Falcaria, Fuernrohria, Gongylosciadium, Grammosciadium s.s., Hladnikia, Olymposciadium, etc. Rhabdosciadium anatolyi sp. nov. is described and illustrated as a new species from Hakkâri province, eastern Turkey. It differs from the other taxa of the genus, in addition to its unique geographical range, in the large terminal leaf lobes with regularly serrated margin, mainly ternate primary basal segments of leaves, and long internodes.

Organic carbon transfer and ecosystem functioning in the terminal lobes of the Congo deep-sea fan: outcomes of the Congolobe project

Organic carbon transfer and ecosystem functioning in the terminal lobes of the Congo deep-sea fan: outcomes of the Congolobe project

Semenovia gyirongensis (Apiaceae), a new species from Xizang, China.

Based on morphology and molecular data, a new species Semenovia gyirongensis Q.Y.Xiao & X.J.He, from Gyirong County, Xizang, China, is described and illustrated. It is morphologically most similar to S. malcolmii (Hemsley & Pearson) Pimenov, but differs in its cylindric much-branched root, intensively branching long underground caudex with distinct nodes, narrowly ovate to ovate terminal leaf lobes, oblong bracts with obtuse-rounded or cuneate apex.

Palynofacies reveal fresh terrestrial organic matter inputs in the terminal lobes of the Congo deep-sea fan

The Congo deep-sea fan is directly connected to the Congo River by a unique submarine canyon. The Congo River delivers up to 2×1012gPOC/yr, a part of which is funnelled by the submarine canyon and feeds the deep-sea environments. The more distal part of the Congo deep-sea fan, the terminal lobe area, has a surface of 2500km2 and is situated up to 800km offshore at depths of 4750–5000m. It is a remarkable place to study the fate and distribution of the organic matter transferred from the continent to the deep ocean via turbidity currents. Forty-two samples were analyzed from the terminal lobes, including sites from the active channel, one of its levees and an abandoned distal channel. Samples were collected using multitube cores and push-cores using a Victor 6000 ROV, which surveyed the dense chemosynthetic habitats that locally characterize the terminal lobes. Palynofacies reveal a remarkably well-preserved, dominantly terrestrial particulate organic matter assemblage, that has been transferred from the continent into the deep-sea by turbidity currents. Delicate plant structures, cuticle fragments and plant cellular material is often preserved, highlighting the efficiency of turbidity currents to transfer terrestrial organic matter to the sea-floor, where it is preserved. Moreover, the palynofacies data reveal a general sorting by density or buoyancy of the organic particles, as the turbulent currents escaped the active channel, feeding the levees and the more distal, abandoned channel area. Finally, in addition to aforementioned hydrodynamic factors controlling the organic matter accumulation, a secondary influence of chemosynthetic habitats on organic matter preservation is also apparent. Palynofacies is therefore a useful tool to record the distribution of organic matter in recent and ancient deep-sea fan environments, an important topic for both academic and petroleum studies.

Cold-seep-like macrofaunal communities in organic- and sulfide-rich sediments of the Congo deep-sea fan

Methane-rich fluids arising from organic matter diagenesis in deep sediment layers sustain chemosynthesis-based ecosystems along continental margins. This type of cold seep develops on pockmarks along the Congo margin, where fluids migrate from deep-buried paleo-channels of the Congo River, acting as reservoirs. Similar ecosystems based on shallow methane production occur in the terminal lobes of the present-day Congo deep-sea fan, which is supplied by huge quantities of primarily terrestrial material carried by turbiditic currents along the 800km channel, and deposited at depths of up to nearly 5000m. In this paper, we explore the effect of this carbon enrichment of deep-sea sediments on benthic macrofauna, along the prograding lobes fed by the current active channel, and on older lobes receiving less turbiditic inputs. Macrofaunal communities were sampled using either USNEL cores on the channel levees, or ROV blade cores in the chemosynthesis-based habitats patchily distributed in the active lobe complex.The exceptionally high organic content of the surface sediment in the active lobe complex was correlated with unusual densities of macrofauna for this depth, enhanced by a factor 7–8, compared with those of the older, abandoned lobe, whose sediment carbon content is still higher than in Angola Basin at same depth. Macrofaunal communities, dominated by cossurid polychaetes and tanaids were also more closely related to those colonizing low-flow cold seeps than those of typical deep-sea sediment. In reduced sediments, microbial mats and vesicomyid bivalve beds displayed macrofaunal community patterns that were similar to their cold-seep counterparts, with high densities, low diversity and dominance of sulfide-tolerant polychaetes and gastropods in the most sulfidic habitats. In addition, diversity was higher in vesicomyid bivalve beds, which appeared to bio-irrigate the upper sediment layers. High beta-diversity is underscored by the variability of geochemical gradients in vesicomyid assemblages, and by the vesicomyid population characteristics that vary in density, size and composition. By modifying the sediment geochemistry differently according to their morphology and physiology, the different vesicomyid species play an important role structuring macrofauna composition and vertical distribution. Dynamics of turbiditic deposits at a longer temporal scale (thousands of years) and their spatial distribution in the lobe area also resulted in high heterogeneity of the “cold-seep-like communities”. Dynamics of chemosynthetic habitats and associated macrofauna in the active lobe area resembled those previously observed at the Regab pockmark along the Congo margin and rapid succession is expected to cope with high physical disturbance by frequent turbiditic events and huge sedimentation rates. Finally, we propose a model of the temporal evolution of these peculiar habitats and communities on longer timescales in response to changes in distributary channels within the lobe complex.

Validating the systematic placement of Eriosynaphe in the genus Ferula (Apiaceae: Scandiceae: Ferulinae) linked with the description of Ferula mikraskythiana sp. nov. from Romania

The genus Eriosynaphe had a peculiar taxonomic history by having been considered also as member of the genus Johrenia in addition to originally having been established in Ferula. It has traditionally been regarded as monotypic and no previous molecular study examined its phylogenetic position. Based on sequences of the nrDNA ITS region, here we show that Eriosynaphe is ‘deeply’ nested in one of the well supported and repeatedly recognised clades of Ferula, thus arguing for its return to the genus Ferula. Additionally, a new species, Ferula mikraskythiana endemic to the Dobrogea region of southeastern Romania is described in the present paper. This species, with its overall habit and mericarp structure, closely resembles Eriosynaphe longifolia though it differs from the latter by its much larger stature, the morphology of the leaf terminal lobes and a distinct phenology. Moreover, F. mikraskythiana is a narrow endemic to a region beyond (westward to) the wide distribution range of E. longifolia.

Two new species of Cossura (Cossuridae, Annelida) from the terminal lobes of the Congo River deep-sea fan

Two new species of Cossura Webster & Benedict, 1887 were found in material collected during sampling from the terminal lobes of the Congo deep-sea fan. They were described using light and scanning electron microscopy. Cossura platypus sp. nov. has 15–17 thoracic chaetigers, a prostomium longer than it is wide, with a widely rounded anterior margin, an abruptly expanded posterior prostomial ring the same length as the peristomium, without a mid-ventral notch, a branchial filament attached to the midlength of chaetiger 3, and a pygidium with three anal cirri. Cossura platypus sp. nov. is similar to C. brunnea Fauchald, 1972 but differs in the shape of the prostomium, which is widely rounded anteriorly in C. platypus sp. nov. and is broadly triangular in C. brunnea; furthermore, C. platypus sp. nov.is uniformly pale, whereas C. brunnea has dark pigmentation. Cossura candida Hartman, 1955 differs from C. platypus sp. nov. in the conical shape of the prostomium and 24–35 thoracic chaetigers. Cossura flabelligera sp. nov. has 16–19 thoracic chaetigers, a conical prostomium, and a branchial filament arising from the posterior part of chaetiger 2; the entire body, including the chaetae, is covered by a thick mucous sheath similar to the tunic of flabelligerids. Cossura flabelligera sp. nov. resembles C. longocirrata Webster & Benedict, 1887 in the position of the branchial filament, the shape of the prostomium, and the number of thoracic chaetigers; it differs in having a thick mucous sheath. This character seems to be unique for the Cossuridae.