Wedge Clam Research Articles

MORPHOLOGICAL AND MOLECULAR CHARACTERIZATION OF Donax faba (BIVALVIA: DONACIDAE) OBTAINED FROM KUTANG BEACH, LAMONGAN, INDONESIA

ARTICLE HIGLIGHTSThis study revealed 19 morphological variations of edible wedge clams, Donax faba (Bivalvia: Donacidae), from Kutang Beach, Lamongan, Indonesia, which has significant role as part of coastal ecosystem.This reseach also highlights the DNA barcoding of Donax faba based on COI gene (Cytochrome C Oxidase Subunit I).The average genetic distance of the research samples was 0.46%, while the value of this parameter between the research samples and the ingroup was found to be 1.51%. ABSTRACTDonax faba is a type of wedge clams with significant ecological and economic roles, as well as variations in color, pattern, and morphometric properties. Recently, a particular population of unidentified D. faba was reported from Kutang Beach, Lamongan, Indonesia. Therefore, this research aimed to assess the morphological variations and molecular characteristics of D. faba obtained from Kutang Beach based on COI gene. A total of 288 samples were collected during the lowest tide for morphological characterization of the color, pattern, and morphometrics of the shells. Additionally, molecular characterization was conducted based on the composition of nucleotide bases and amino acids of COI gene, genetic distance, as well as the relationships. The results showed that D. faba had 19 morphological variations, among which the most dominant type contained a whitish exterior with brown spots and a whitish purple interior. The average genetic distance of the samples was 0.46%, while the value was calculated as 1.51% between the samples and the ingroup. Automatic Barcode Gap Discovery (ABGD) analysis performed using a prior maximal distance of 0.001 showed the separation of these species into distinct categories.

Resource partitioning of a Mexican clam in species-poor Baltic Sea sediments indicates the existence of a vacant trophic niche

Invasive species are often generalists that can take advantage of formerly unexploited resources. The existence of such vacant niches is more likely in species-poor systems like the Baltic Sea. The suspension feeding wedge clam, Rangia cuneata, native to estuarine environments in the Gulf of Mexico, was sighted for the first time in the southeastern Baltic in 2010 and a few years later in the northern Baltic along the Swedish coast. To explore possible competition for food resources between R. cuneata and the three native clams inhabiting Baltic shallow soft bottoms, stable isotope and fatty acid analyses were conducted. There was no overlap between R. cuneata and any of the native species in either stable isotope or fatty acid niches. This suggests efficient partitioning of resources; multivariate analyses indicate that separation was driven mainly by δ13C and by fatty acids reflecting diatoms and cyanobacteria, respectively (e.g. 16:1ω7 and 18:3ω3). R. cuneata reflected seasonal variation in phytoplankton more than other clams reflecting higher trophic plasticity. In conclusion, the addition of R. cuneata to the Baltic shallow soft bottoms suggests the existence of a vacant trophic niche in these sediment habitats, however the long-term effects on other species and nutrient cycling requires further studies focusing on the population dynamics of R. cuneata and its impact on the Baltic Sea ecosystem.

Study of the dynamics of the microbial communities in the wedge clam Donax trunculus (Linnaeus, 1758) from the Bulgarian aquatory of the Black Sea

In the present work, we investigated the dynamics of the microbial communities in the wedge clam Donax trunculus (Linnaeus, 1758) from the Bulgarian coastal waters of the Black Sea. The samples were collected in the period of January 2020 until December 2022 from Arkutino, Ahtopol, Obzor and Tsarevo. The BIOLOG system was used for microbiological determination. In our investigation were isolated the following microorganisms: Enterococcus cancerogenus, Enterococcus hirae, Escherichia vulneris, Citrobacter farmeri, Acinetobacter gyllenbergii, Enterococcus hirae, Escherichia vulneris, Enterobacter cloacae, Escherichia hermannii, Pseudomonas mendocina, Pseudomonas fulva, Pseudomonas alcaligenes, Pseudomonas putida, Acinetobacter johnsonii, Acinetobacter gyllenbergii, Enterococcus hirae, Escherichia vulneris, Enterococcus gallinarum, Citrobacter sedakii, Pseudomonas putida, Streptococcus lugdunensis, Enterococcus casseliflavus, Vibrio cincinnatiensis, Vibrio alginolyticus, Vibrio parahaemolyticus, Enterococcus hirae, Streptococcus aureus, Staphylococcus lugdunensis and Enterococcus casseliflavus. During the winter period, we detected the presence of Pseudomonas sp. – P. alcaligenes, P. putida, and A. gyllenbergii. In the autumn months we isolated C. sedakii, C. farmeri, A. gyllenbergii, A. johnsonii, P. fulva and E. casseliflavus. In the spring, E. cancerogenus, E. hirae and Pseudomonas mendocina were found. During the summer, the highest biodiversity of microorganisms - E. hirae, E. vulneris, E. cloacae, E. gallinarum, P. putida, V. cincinnatiensis, V. alginolyticus, V. parahaemolyticus, S. aureus, E. hermannii and S. lugdunensis were registered. Although our three-year research showed that some species are permanent and others are transient, we tend to accept the conclusion that there is only a transient microbiota in mussels and it changes depending on environmental conditions or is a result of pollution of the Black Sea.

Annual Reproductive Cycle and Meat Yield of the Wedge Clam Donax trunculus Linnaeus, 1758 from Black Sea

Annual Reproductive Cycle and Meat Yield of the Wedge Clam Donax trunculus Linnaeus, 1758 from Black Sea

Management and ecology of the wedge clam (Donax trunculus) in the NW Mediterranean Sea: The case of Ebro Delta (NE Spain)

The wedge clam (Donax trunculus) is one of the most prized clam species fished in the EU. Clam fisheries have experienced a dramatic decline during the last decades on Spanish coasts resulting in the progressive closure of fishing grounds. The Ebro Delta (NW Mediterranean Sea) is one of the few areas of the Spanish coast where there is still some fishing activity. In this context, the main objectives of this study were: to provide novel data on the ecology of this species and to analyse the management of D. trunculus fisheries in the Ebro Delta. The results showed a depth segregation phenomenon and suggested that D. trunculus performs two migrations during its benthic life cycle, i.e., (1) the settlement of planktonic larvae occurs more intensely in the deepest part of its bathymetric distribution, where the survival was more intense. As clams progressively increase in size, they move to shallower areas; (2) adults tend to move back to the deepest part of their bathymetric distribution as they increase in size. The management of D. trunculus has improved significantly in the last decade. However, some issues are still unsolved (e.g., fishing gear limits are unclear; population boundaries do not coincide with political boundaries). Moreover, the shallower areas where juveniles are located concentrate the highest fishing pressure over the stock.

Recreational harvesting of the wedge clam (Donax trunculus) in southern Portugal: Characterization of the activity based on harvesters’ perception and local ecological knowledge

This study was the first attempt to characterize the recreational harvesting of the wedge clam (Donax trunculus). For this purpose, 403 face-to-face interviews were performed in the summers of 2018 and 2019 in southern Portugal. The majority of the harvesters frequented the selected beaches during holidays and collected wedge clams as a hobby for an appetizer. The respondents reported an inter-annual variation in their catches of wedge clam with a decreasing abundance in 2018 followed by a recovery in 2019, but with more recreational harvesters collecting undersized individuals. Although most harvesters declared to consume D. trunculus, only a few bought wedge clams being the clams’ size a secondary factor in their valorization. The majority of the recreational harvesters did not know the species' minimum conservation reference size nor the legally allowed maximum daily catch. It was estimated that recreational harvesters can collect 13 tonnes of wedge clams during the summer season along the southeastern coast of Algarve. Even though manual harvesting is not an efficient fishing technique, the lack of selectivity of harvesters can eventually compromise the resilience of D. trunculus populations. Despite most respondents affirmed to get informed about marine biotoxins, most surveys were done during periods of interdiction for shellfish harvesting. The present results revealed that the population is still unaware of the health risks of consuming shellfish contaminated with biotoxins. Educational activities and awareness campaigns are required to further inform recreational harvesters about the regulations in force for this activity and the sanitary threats of marine biotoxins.

Seasonal Variations in the Trace Elements and Mineral Profiles of the Bivalve Species, Mytilus galloprovincialis, Chamelea gallina and Donax trunculus, and Human Health Risk Assessment.

This study aimed to provide data on selected toxic (Cd, Pb and Ni), essential (Cr, Cu, Fe, Mn and Zn) and microelement (Na, K, Ca and Mg) concentrations in edible tissues of the Mediterranean mussel (Mytilus galloprovincialis), striped venus clam (Chamelea gallina) and the wedge clam (Donax trunculus). Samples were collected from the Black Sea (Bulgaria) four times over, a period of one year (2022). In comparison with the maximum permissible levels set by the EU and USFDA, all elemental concentration found in the bivalve species were lower than the prescribed limits. An estimation of the dietary metal intake through calculation of the target hazard quotients (THQ), hazard index (HI) and target risk (TR) was performed. The target hazard quotient (THQ) for individual metal and HI for combined metals were lower than 1, indicating no health risk for consumers due to the intake of either individual element or combined ones. The target risk value for toxic inorganic Pb and Cr was below 10-6, indicating no carcinogenic risk. According to these results, the consumption of these bivalve species is completely safe for human health.

The wedge clam (Donax trunculus) hand-operated fishery in the NW Mediterranean Sea: Landings, catch composition, damage rates and impact of fishing activity

The bivalve wedge clam Donax trunculus is a highly valued species in Spain, but wild stocks have decreased in the Mediterranean region in recent decades. Internal demand exceeds the existing supply derived from local production. Hand-operated dredge fishery is still important in some coastal areas of Spain, such as the Ebro Delta (NE Spain). However, scientific information is lacking on most aspects of this fishery which is essential for its sustainable management. In this context, this study aimed to provide the first characterization of the hand-operated dredges fishery; evaluate the damage of this fishery on the megabenthic fauna; and analyze the impact of the fishing activity on the wedge clam. Our results indicate that landings declined dramatically since the mid-1990s and the main causes for this decline are postulated. Fishing effort was highly seasonal, being more intense from March to September. The discard fraction was very small (5.74% in abundance and the 3.74% in biomass) and 61.93% of the discards did not suffer damage. Clam fishing activity had an impact on recruit density in the short term (3 months), but not on recruit size and commercial fraction density, biomass and size. Our results provide tools for a better management of this type of fisheries.

Testing macroecological hypotheses in sandy beach populations: the wedge clam Donax hanleyanus in South America

Large-scale spatial and temporal variability in environmental conditions may result in differences in life-history traits, population demography, and abundance of sandy-beach species. We analyzed the effects of salinity, chlorophyll a (chl a), and sea surface temperature (SST) on population parameters of the wedge clam Donax hanleyanus from 75 South American sandy beaches covering a 15° latitudinal range. Generalized modeling results showed that between-beach differences in abundance, population structure, growth performance, productivity, mortality, and individual shell mass were mainly explained by salinity fluctuations, with chl a and SST as secondary contributors, overriding, in most cases, local habitat features (Dean’s parameter, grain size, slope). Our results provide valuable insights into macroscale ecological processes, setting a basis to delineate conservation guidelines at large spatial scales that respond to the potential effects of climate variability and change on sandy beach populations.

Integrated biomarker responses and metal contamination survey in the wedge clam Donax trunculus from the Atlantic coast of Morocco.

In Morocco, the marine environment has always been a major occupation for socioeconomic activities (industry, tourism, urbanization, etc.). Thus, this work displays a case study of Taghazout coast in the central Atlantic part of the country, which becomes the center of several development projects, such as the touristic resort Taghazout Bay. In the aim to assess the health status of this coastal ecosystem, a multi-indicator approach based on the response of biomarkers in the wedge clam Donax trunculus was adopted during two years (2016/2017). The undertaken investigations on the response of biomarkers (AChE, GST, MDA, and CAT) in the sentinel species D. trunculus showed an activation of defense mechanisms in this bivalve, which would imply exposure to chemical stress in this ecosystem. The monitoring of seasonal bioaccumulation of cadmium (Cd), lead (Pb), and copper (Cu) by D. trunculus indicates that the bivalves collected have been exposed to these metal sources in the study area. In addition, the correlation study has reported a significant effect of environmental parameters on biomarker response. Overall, the multi-indicator approach has clearly revealed the health status of Taghazout coast registered in a coastal urbanization.

Uptake of Microplastics in the Wedge Clam Donax trunculus: First Evidence from the Mediterranean Sea

The Mediterranean Sea is affected by microplastic contamination, and several methods have been developed to investigate the degree of environmental plastic pollution. Among these, the use of bioindicators is strongly suggested, and in particular bivalves are sensitive sentinel organisms of the level of microplastic contamination. The wedge clams Donax trunculus is an important edible species for the Mediterranean, area but only rudimentary knowledge is available about microplastic contamination in this species, and no data are available about this topic in the Mediterranean Sea. Therefore, the main aim of this study was to investigate the microplastic accumulation in the wedge clam and in different water samples (seawater and purged water) in the Tyrrhenian Coast from September to June. The microplastics found were characterized by color, shape, and polymer type through micro-FTIR. For the first time, the microplastic contamination in wedge clams of the Mediterranean Sea was recorded. In September was recorded the highest concentration of microplastics in wedge clams (0.56 MPs/individual). Only microfiber shapes of different colors and types of polymers were found in both wedge clams and water samples. Polyethylene terephthalate was the most common polymer in wedge clams, while a diversified composition was found in water samples. The most common size both in wedge clams (42.8%) and water samples (≥50%) was in the range 0.1–1 mm. Our results highlight the presence of microplastics in an edible species widely commercialized in the Mediterranean Basin and the possibility of using this species to assess microplastic pollution.

The wedge clam Donax trunculus Linnaeus, 1758 (Bivalvia Donacidae) as bioindicator for monitoring of the Annaba gulf (Algeria): measurements of lipid and malondialdehyde rates during the reproduction (Spring 2021)

The wedge clam Donax trunculus Linnaeus, 1758 (Bivalvia Donacidae) as bioindicator for monitoring of the Annaba gulf (Algeria): measurements of lipid and malondialdehyde rates during the reproduction (Spring 2021)

Seasonal variations and human health risk assessment of trace elements in the bivalve ecosystem in the Sea of Marmara

ABSTRACT Twelve trace elements were studied in four economically important bivalve molluscs (Mediterranean mussel, manila clam, striped venus clam, and truncated wedge clam) from the southern Marmara Sea for seasonal bioaccumulation and human health risk assessment. According to the findings, Fe and Zn were the most accumulative and element concentrations changed considerably (P < 0.05) between seasons and species. Daily, weekly, monthly intake and target hazard quotients of the trace elements were estimated and compared with maximum limits. The results revealed that consuming these bivalve molluscs from the southern Marmara Sea could be considered safe for human consumption. Nevertheless, further monitoring is needed in order to better follow the development in time of elemental pollution due to increasing environmental pressure on the Marmara Sea basin, together with research on other different bioaccumulative organisms.

First report and molecular analysis of population stability of the invasive Gulf wedge clam, Rangia cuneata (G.B. Sowerby I, 1832) in the Pomerian Bay (Southern Baltic Sea)

Native to the Gulf of Mexico, Gulf wedge clam (Rangia cuneata) has been successfully invading Baltic Sea since first introduction with ballast waters in 2010. In this study, we report new occurrence sites in the Pomeranian Bay and in the brackish water of the Szczecin Lagoon. We aimed to describe the structure and stability of the new population of Gulf wedge clam using ecological indicators (i.e. condition index, length-at-age) and a molecular approach targeting first cytochrome oxidase subunit (COX1) fragments. The study showed an age structure dominated by adult clams (aged 4+), rather than the often reported juveniles. We found that the condition of the R. cuneata population in the Pomeranian Bay is characteristic of the expansion model after bottleneck. Genetic analyses indicated low nucleotide (π = 0.00387 ± 0.00012) and haplotype (h = 0.79 ± 0.018) diversity. A haplotype network inferred by a median-joining method showed lack of haplotype H6 (Chesapeake Bay, NW Atlantic) and numerous individuals with haplotype H1 (Gulf of Mexico). Demographic parameters (non-significant Tajima’s D = 2.058, Fu’s Fs = 2.298, Fu and Li’s D* = 1.195, and significant Fu and Li’s F test = 1.757) suggested that the population underwent a moderate population bottleneck, while analysis of mismatch distribution showed a bimodal shape which may imply population admixture as a consequence of “allelic surfing”. Moreover, we concluded that R. cuneata has successfully invaded the basin of the LNG terminal, although our study proved non-linear growth of this species.

Trace metal accumulation in tissues of wedge clams from sandy habitats of the Bulgarian Black Sea coast

The aim of the present study was to carry out an initial screening of trace metals bioaccumulation in soft tissues of the wedge clam (Donax trunculus Linnaeus, 1758) from different localities of the Bulgarian Black Sea coastal area and to evaluate the bioindicator potential of this species. Wedge clams were collected in June and September 2020 from sublittoral sandy habitats at different localities of the Bulgarian Black Sea coast. Soft tissues of individual clams were digested with nitric acid followed by ICP-OES analytical determination. The content of trace metals in the wedge clams differed significantly amongst localities. Higher metal content was present in wedge clams from Sveti Vlas, Shkorpilovtsi, Slanchev Bryag, Ahtopol and Kranevo. The highest values of lead (Pb) (2.51 mg/kg) and cadmium (Cd) (0.32 mg/kg) were found in samples from Sveti Vlas and the highest concentration of copper (Cu) (34.12 mg/kg), iron (Fe) (269.52 mg/kg) and nickel (Ni) (0.32 mg/kg) were detected in wedge clams from Shkorpilovtzi. Maximum content of chromium (Cr) (0.58 mg/kg) was present in samples from Slanchev Bryag, together with high values of Fe. The highest concentration of zinc (Zn) (18.04 mg/kg) together with high values of Cr and Fe were measured in wedge clams from Irakli. In conclusion, the wedge clams from the localities known to have higher coastal inflows and touristic pressures, i.e. Varna, Shkorpilovtzi, Sveti Vlas, Slanchev Bryag and Ahtopol accumulated significantly higher metal elements in their tissues. Only few significant seasonal differences in the concentration of metal elements in wedge clams were present and the observed seasonal variations were probably connected to the hydrological parameters of the ecosystems. The wedge clam D. trunculus is a suitable bioindicator for assessment and monitoring of metal pollution in the Bulgarian Black Sea environment.

State of the antioxidant defense system in wedge clams from Bulgarian Black Sea as a measure of resistance to environmental impacts

Pollution and climate change can induce oxidative stress (OS) in aquatic organisms. Reduced activity or incoordination between antioxidant enzymes in marine bivalves may cause cellular impairment with effects on higher levels of ecological organization. The present study aims to assess the condition factor and the activity of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione-S-transferase (GST), and glutathione concentration (GSH) in soft tissues of Donax trunculus (Linnaeus, 1758) as indicators of the state of marine ecosystems along the Bulgarian Black Sea coast. The wedge clams were sampled manually from different localities in June and in September. The activity of antioxidant enzymes and GSH concentrations varied both seasonally and among localities. Higher values of GSH, SOD and GPx were registered in wedge clams collected in autumn compared to those collected in summer. In wedge clams higher activity of the major phase II detoxification enzyme GST was observed in summer at localities with intensive tourism, suggesting an activation of the cell detoxification processes, presumably in response to increased environmental pressure. In conclusion, the observed presence of elevated enzyme activities suggested activation of the antioxidant protection system of the wedge clams in response to environmental pressure, indicating their ability to cope with induced OS and adapt to local conditions, and thus maintain ecosystem health.

Assessment of PAHs accumulation in Donax trunculus (Linnaeus, 1758) (Bivalvia, Donacidae) from the Bulgarian Black Sea Coast

Anthropogenic pollution of marine ecosystems is one of the main sources of polycyclic aromatic hydrocarbons (PAHs). Marine bivalves are often used as bioindicators of environmental pollution due to their wide distribution and capability of xenobiotic bioaccumulation. The aim of the present study was to assess the presence of PAHs in soft tissues of wedge clams Donax trunculus (Linnaeus, 1758), collected from sublittoral sandy habitats at different locations off the Bulgarian Black Sea coast. Wedge clams from the different locations showed variations in the content of accumulated PAHs’ compounds. The concentrations of PAHs were measured by gas chromatography system with mass spectrometry detection. The total PAHs content (sum of 13 PAHs’ compounds) measured was in the range from 5.59 to 50.50 ng/g wet weight and was comparable with other European studies. The compounds phenanthrene and fluorene were most abundant in all analyzed samples. The results showed that low molecular weight (LMW) PAHs (2 and 3 aromatic rings) were predominant, accounting for 91% of the total PAHs levels, while high molecular weight (HMW) PAHs (4–5- and 6- rings) presence was 8.9% on average. The ratio LMW/HMWPAHs was higher than one, suggesting predominant pollution of petrogenic origin. The concentrations of benzo (a)pyrene did not exceed the limit set in EC Regulation although it was detected in 20% of the analyzed samples. In conclusion, maximum overall PAHs content was found in clams from Arkutino, while minimum PAHs content was present in samples from Elenite. The Sum PAH4 (sum of four polycyclic aromatic hydrocarbons: benzo[a]pyrene, chrisene, benzo[a]anthracene, and benzo[b]fluoranthene) in the wedge clams for all localities studied was below legislation limits. Data from the present research can be used for assessing pollution levels in the marine environment and also risk of human exposure to PAHs using D. trunculus as bioindicator species.

Seasonal variations of the microflora of wedge clam Donax trunculus (Linnaeus, 1758) from the region of Arkutino (Bulgarian Black Sea aquatory)

The main goal of the present study was to investigate the impact of the state of the environment on the microbiota of the wedge clam Donax trunculus (Linnaeus, 1758) from the region of Arkutino (Bulgarian Black Sea aquatory). The species Enterococcus hirae was isolated during the summer (from May to August). The species P. mendocina prefers the warmer months and the species P. alcaligenes the colder ones. The temperature followed a course of decrease during the period September 2020 to January 2021, followed by a slow increase from February 2021. Comparing May 2020 with May 2021, it became evident that in 2021 the temperature was 1.5 °C lower. We can say that the number of the species P. alcaligenes was twice as high in May 2021. It is likely that this species preferred lower optimum temperatures and constant other parameters. For the species Enterococcus hirae such dependence was not observed - the number remained constant in May, but with increasing temperature the number of microorganisms decreased during the summer months. The species seemed to preferably develop at pH 7.78. The species A. gyllenbergii preferably grows at temperatures between 20.3–25.7 °C and the optimal temperature was 25.7 °C. For C. farmeri the optimum conditions were temperature 26.2 °C and pH 7.3. The species E. vulneris was probably related not only to the increase in water temperature, but also to the anthropogenic factor, as it was found only in July.

Description of a New Species of Bacciger (Digenea: Gymnophalloidea) Infecting the American Gizzard Shad, Dorosoma cepedianum (Lesueur, 1818), and Molecular Characterization of Cercaria rangiae Wardle, 1983, with Molecular Phylogeny of Related Digenea

A new species of Bacciger Nicoll, 1914, is described from the digestive tract of the American gizzard shad, Dorosoma cepedianum (Lesueur), in some inland waterways of Mississippi, and in Mobile Bay, Alabama, U.S.A. This now represents the only nominal species in the genus from the northwest Atlantic Ocean or inland tributaries of eastern North America north of Mexico. Two potentially close relatives that range in the northwest Atlantic Ocean are Baccigeroides ovatus (Price, 1934) Cutmore, Bray and Cribb, 2018, and Pseudobacciger manteri Nahhas and Cable, 1964. The new species differs from Bo. ovatus mainly by having the genital pore opening immediately anteriad from the ventral sucker rather than far anteriad from it at the pharynx level, and from P. manteri mainly by having a distinct cirrus sac rather than having the terminal genitalia free in the parenchyma. The 3 genera are currently classified in the Faustulidae Poche, 1926. Although life cycles are unknown for the American species, evidence from life history of the related species Bacciger bacciger (Rudolphi, 1819) Nicoll, 1914, and Pseudobacciger harengulae (Yamaguti, 1938) Nahhas and Cable, 1964, combined with molecular phylogenetic evidence, indicate that the studied digeneans likely have a nonoculate trichocercous cercaria. We discovered sporocysts containing nonoculate trichocercous cercariae we identified as Cercaria rangiae Wardle, 1983, infecting the viscera of the Gulf wedge clam, Rangia cuneata (G. B. Sowerby I), in the Pascagoula River, Mississippi, U.S.A. We generated the internal transcribed spacer 2 (ITS2) region and a portion of the 28S rDNA gene from the new species and C. rangiae. Dissimilarity at both sequences demonstrated that the stages were not conspecific. Bayesian inference analyses applied separately to the ITS2 region, and the partial 28S rDNA gene, resulted in trees with similar topology, both depicting the new species and C. rangiae as sister taxa. The possible identity of C. rangiae and the phylogenetic relationships among species of Bacciger and related genera are discussed. We consider Bacciger lesteri Bray, 1982, and Bacciger sprenti Bray, 1982, incertae sedis in the Microphalloidea Ward, 1901. All other species of Bacciger, and species belonging in Pseudobacciger Nahhas and Cable, 1964, and Baccigeroides Dutta, 1995, are transferred from the Faustulidae to the Gymnophalloidea Odhner, 1905, where their familial affinities remain incertae sedis.

The wedge clam Donax trunculus L., 1758 as a bioindicator of microplastic pollution

This study describes the use of D. trunculus as a bioindicator of microplastic (MPs) pollution due to beach urbanization related to the development of the Taghazout Bay tourist resort in Morocco. In six sites located on the coast, MPs densities ranged from 1.75 to 5.93 items per gram of D. trunculus wet weight. MPs contamination was significantly influenced spatiotemporally by the urbanization degree in the area. The shapes found were fibers (90.5%) and fragments (9.5%). The Fourier Transform Infrared Spectroscopy (FTIR) analysis reported two polymers: polyethylene (65%) and polypropylene (35%). MPs colors were dark and light, with a predominance of light blue (23.8%). The species ingested different sizes of MPs, mainly the 0.1 and 0.5 mm fractions. Scanning Electron Microscope coupled with an energy dispersive X-ray analyzer (SEM/EDX) revealed weathered MPs with chemical elements adhered to their surface (Cu, Fe, Mg, S, Cl, etc.). The results of this study recommend the use of D. trunculus as a new bioindicator of MPs pollution following an urban change in the coastal scenery. Also, a sustainable coastal management must be implemented in the study area.