ICES IDENTIFICATION LEAFLETS FOR PLANKTON. FICHES D’IDENTIFICATION DU ZOOPLANCTON. Corystidae Samouelle, 1819 and Thiidae Dana, 1852

Families Corystidae and Thiidae comprise 13 species of burrowing crabs, and only 2 of them inhabits the ICES area. These species are Corystes cassivelaunus, belonging to the family Corystidae, and Thia scutellata in the family Thiidae. Both are warm-water species and inhabit the sublittoral zone in sandy bottoms. The larval series of the two species is known to include two phases: zoea and megalopa. The zoeal stages are the dispersal phase, and the megalopa is the dispersive and specialised recruitment phase. This leaflet provides the distinctive characteristics of the larval stages for C. cassivelaunus and T. scutellata, and illustrated keys are included to improve the identification of zoeae and megalopa stagesEn prens

Marine litter, the new plague of seas and oceans

En prens

Análisis genéticos permiten identificar y describir larvas de cangrejos marinos no conocidas hasta el momento

Peer reviewe

DNA barcoding allows identifcation of undescribed crab megalopas from the open sea

Megalopas of 15 brachyuran crab species collected in the open sea plankton, and unknown until now, were identified using DNA barcodes (COI and 16S rRNA). Specimens belonging to the families Portunidae, Pseudorhombilidae and Xanthidae (Crustacea, Decapoda, Brachyura), and corresponding to the species Achelous floridanus, Arenaeus mexicanus, Callinectes amnicola, C. arcuatus, C. ornatus, C. toxones, Charybdis (Charybdis) hellerii, Portunus hastatus, Thalamita admete, Scopolius nuttingi, Etisus odhneri, Liomera cinctimanus, Neoliomera cerasinus, Pseudoliomera variolosa, and Williamstimpsonia stimpsoni, are described and illustrated, and compared with other congeneric species previously described. We also provide a new geographical record for N. cerasinus and the most remarkable features for each species.En prens

Larval development of the pea crab Afropinnotheres monodi Manning, 1993 (Decapoda, Pinnotheridae) using plankton-collected and laboratory-reared specimens: effects of temperature

The aim of this study was to assess the effect of temperature on the survival and duration of larval development in the African pea crab Afropinnotheres monodi, as well as to describe its larval stages. We studied larvae reared in the laboratory and also specimens collected from plankton from the Gulf of Cádiz at two different temperatures. According to the results of this study, larval development of A. monodi involves four zoea stages and one megalopa and lasts around 25 days at 25°C, and longer than 40 days at 19°C. Such a temperature-related duration of this dispersive phase may be causing a higher recruitment to parental populations during the summer, but a higher dispersal to new locations during the rest of the year, a seasonal pattern of dispersion which could favour the successful expansion of this non-native species into European waters. The identification of both larval phases from plankton samples and adult specimens was carried out using morphological characters and molecular techniques. Both the 16S mtDNA sequences of this species, now available in GenBank, and the larval descriptions provided by this study could help to establish an early alert for the detection of this African species in its northward expansion

Spatial distribution and community structure of megabenthic bivalves in the subtidal area of the Gulf of Cádiz (SW Spain)

VENUSEstudio integral de los bancos naturales de moluscos bivalvos en el Golfo de Cádiz para su gestión sostenible y la conservación de sus hábitats asociado

Spatial distribution patterns of the striped venus clam (Chamelea gallina, L. 1758) natural beds in the Gulf of Cádiz (SW Spain)

VENUSEstudio integral de los bancos naturales de moluscos bivalvos en el Golfo de Cádiz para su gestión sostenible y la conservación de sus hábitats asociado

Interannual fuctuations in connectivity among crab populations (Liocarcinus depurator) along theAtlantic‑Mediterranean transition

An interesting evolutionary question that still remains open is the connectivity between marine populations. Marine currents can favour the dispersal of larvae or adults, but they can also produce eddies and gyres generating oceanographic fronts, thus limiting gene flow. To address this subject, we selected the Atlantic-Mediterranean transition, where several fronts are located: Gibraltar Strait (GS), Almeria-Oran Front (AOF) and Ibiza Channel (IC). Seven populations of the marine crab Liocarcinus depurator (Cadiz, West and East Alboran, Alacant, Valencia, Ebro Delta and North Catalonia) located along this transition were analysed in six consecutive years (2014–2019) using a fragment of the COI (Cytochrome Oxidase subunit I) gene. All sequences (966) belonged to two well defined haplogroups: ATL (most abundant in Atlantic waters) and MED (predominant in Mediterranean waters). Following a geographic variation, the frequency of ATL decreased significantly from Cadiz to North Catalonia. However, this variation presented steps due to the effect of oceanographic restrictions/fronts. Significant effects were recorded for GS (2015, 2017, 2018 and 2019), AOF (all years except 2018) and IC (2016). The intensity and precise location of these fronts changed over time. Multivariate analyses distinguished three main population groups: Cadiz, Alboran Sea and the remaining Mediterranean populations. These findings could be relevant to properly define Marine Protected Areas and for conservation and fisheries policies

Morphology of the megalopa of the mud crab, Rhithropanopeus harrisii (Gould, 1841) (Decapoda, Brachyura, Panopeidae), identified by DNA barcode.

The morphology of the megalopa stage of the panopeid Rhithropanopeus harrisii is redescribed and illustrated in detail from plankton specimens identified by DNA barcode (16S mtDNA) as previous descriptions do not meet the current standard of brachyuran larval description. Several morphological characters vary widely from those of other panopeid species which could cast some doubt on the species’ placement in the same family. Besides, some anomalous megalopae of R. harrisii were found among specimens reared at the laboratory from zoeae collected in the plankton. These anomalous morphological features are discussed in terms of problems associated with laboratory rearing conditions