Four new species of Pilargidae (Annelida: Pilarginae) from the Gulf of Thailand

Four new species belonging to the Family Pilargidae, Ancistrosyllis kornkanokae sp. nov., A. nakkaritae sp. nov., Cabira saithipae sp. nov., and C. thailandica sp. nov. were collected from 9–27 m depth in soft sediments in the Songkhla Sea, Gulf of Thailand. Ancistrosyllis kornkanokae sp. nov. can be distinguished from other species in the genus by the presence of a small median antenna on the prostomium; two pairs of elongate tentacular cirri; and short limbate neurochaetae with unidentate curved pointed tips. Ancistrosyllis nakkaritae sp. nov. is characterized by having a conspicuous median antenna and elongate lateral antennae longer than palps; and short limbate neurochaetae with bifid tips. While Cabira saithipae sp. nov. is characterized by the presence of the first notopodial hook at chaetiger eight, large, conical papillae ont chaetigers 7–17 and the presence of both short, recurved tipped and short, curved tip chaetae in anterior chaetigers. Cabira thailandica sp. nov. is distinguished from other species in the genus by the first notopodial hooks occurring at chaetiger seven and the presence of long, non-limbate capillary neurochaetae with bidentate tips. Updated keys to the genera Ancistrosyllis and Cabira are also provided.

Feeding behaviour and the operculum in Olividae (Gastropoda): the case of Callianax biplicata (G. B. Sowerby I, 1825)

Olividae are marine gastropods living as predators or scavengers on soft sediments. The complex prey handling behaviour of large predatory species includes the storage of food in a pouch formed temporarily by bending and contraction of the posterior foot. Such metapodial pouches had been observed only in Olividae that lack an operculum, prompting the hypothesis that the folding of the metapodium into a pouch biomechanically required the absence of the operculum. Here we report metapodial pouch formation in an operculate olivid, Callianax biplicata (formerly Olivella biplicata). Since the operculum is too small to close the shell aperture in mature C. biplicata, a protective function seems unlikely. The operculum may rather serve as an exoskeletal point for muscle attachment, but may also represent a ‘vestigial organ’ in the process of evolutionary reduction, or an ontogenetic remnant functional at early life stages but not at maturity. Consequently, our observations refute the notion that only inoperculate olivids can form pouches, but not necessarily the idea that the ability to form a metapodial pouch evolved in parallel with operculum reduction

First record and range extension of the transversely-dividing azooxanthellate coral Truncatoflabellum mortenseni Cairns and Zibrowius, 1997 (Scleractinia, Flabellidae) in the Persian Gulf, Western Indo-Pacific Ocean

In the Persian Gulf, Azooxanthellate Scleractinia remain understudied compared to their symbiotic counterparts. Here, we report the presence of azooxanthellate coral Truncatoflabellum mortenseni (Cairns & Zibrowius, 1997) for the first time in Iranian deep waters. This species was found on soft sediments at depths of 83 and 101 m. Given this report, the distribution range of T. mortenseni, previously known to exist only in the Indonesian-Philippine regions, is now expanded to the Persian Gulf.

Human impacts

Coastal soft sediments are closely linked to human activity both on the land and at sea and consequently they are subjected to a wide array of human impacts. Looking for some general patterns in the consequences of impacts, this chapter identifies a range of different ecological changes as a result of direct impacts and then moves to address indirect effects. The chapter looks at the connections between local and global impacts focussing on eutrophication, fishing impacts, sediment run-off from land and plastic pollution. This leads to an introduction into the challenges of addressing multiple stressor effects, cumulative effects and the stress and disturbance-induced homogenisation of seafloor habitats and communities. The history of impact in coastal ecosystems often means that we have no appreciation for what has been lost in terms of biodiversity and ecosystem function. The chapter emphasises that to address the challenges of human-induced changes in soft sediments, we need good knowledge of how seafloor ecosystems function and how ecological systems as a network of interactions respond to change.

A new species of alpheid shrimp tentatively assigned to Salmoneus Holthuis, 1955 (Decapoda: Caridea) from the Ryukyu Islands, Japan

A new alpheid shrimp species, provisionally assigned to the genus Salmoneus Holthuis, 1955, is described and illustrated on the basis of three specimens extracted from intertidal soft sediments on seagrass beds at Iriomote Island, southern Ryukyu Islands, Japan. Salmoneus singularis n. sp. is highly distinctive within the genus in having a pair of postorbital spines on the carapace, otherwise showing some affinities to the species of the S. gracilipes Miya, 1972 group. The possession of paired spines on the dorsolateral surface of the carapace is shared with several members of Triacanthoneus Anker, 2010, which is undoubtedly closely related to Salmoneus. However, the new species cannot be placed in Triacanthoneus because of the absence of a mid-dorsal spine on the carapace.

Soft Sediment Characterization using Seismic Techniques at Beni Suef City, Egypt

It is well known that the local geological characteristics in terms of topographic setting and the existence of soft sediments over bedrock may affect earthquake waves and cause seismic amplification. These effects are called “site effects”. Microtremors which provide an efficient practical tool for site effects estimation were recorded at 43 sites in Beni Suef City, Egypt. The recorded seismic signals were analyzed using the Horizontal-to-Vertical Spectral Ratio (HVSR) method. The targeted site parameters are the fundamental frequency ( f0) and the corresponding amplitude of seismic waves ( A0). Selected H/V curves with clear peak frequency have been inverted to infer the S-wave velocity profile of the underlying sediments. Information about subsurface sediments needed for the inversion process was extracted from available boreholes data. Moreover, the estimated values of f0 and A0 have been used for a preliminary calculation of the seismic vulnerability index ( Kg) which represents an indicator of soil liquefaction potentiality in the event of future earthquakes at the study area. The estimated H/V curves reveals significant variations in f0 and A0 parameters, reflecting variations in the soil characteristics (thickness and type) at the study area. The estimated values of f0 are (0.4–3.7 Hz), and commonly decrease from east to west. The A0 values vary from flat H/V curves (without any clear peak) at rock sites to 7.8 near to the Nile River and in the cultivated areas. The obtained velocity profiles could investigate S-wave structure down to 200 m depth. The estimated Kg varies from 10 to more than 50 μstrain/gal. The highest Kg values are noticed in the west and northwest in the study area were the soft sediments exist with considerable thickness, while the smallest Kg values are noticed in the south east where limestone and stiff soil occur near the ground surface.