Molecular phylogeny and diversity of penaeid shrimps (Crustacea: Decapoda) from South‐East Asian waters

A systematic evaluation on the relationship between hypo-osmoregulation and hyper-osmoregulation in decapods of different habitats

Decapods occupy all aquatic, and terrestrial and semi-terrestrial environments. According to their osmoregulatory capacity, they can be osmoconformers or osmoregulators (hypo or hyperegulators). The goal of this study is to gather data available in the literature for aquatic decapods and verify if the rare hyporegulatory capacity of decapods is associated with hyper-regulatory capacity. The metric used to quantify osmoregulation was the osmotic capacity (OC), the gradient between external and internal (hemolymph) osmolalities. We employ phylogenetic comparative methods using 83 species of decapods to test the correlation between hyper OC and hypo OC, beyond the ancestral state for osmolality habitat, which was used to reconstruct the colonization route. Our analysis showed a phylogenetic signal for habitat osmolality, hyper OC and hypo OC, suggesting that hyper-hyporegulators decapods occupy similar habitats and show similar hyper and hyporegulatory capacities. Our findings reveal that all hyper-hyporegulators decapods (mainly shrimps and crabs) originated in estuarine waters. Hyper OC and hypo OC are correlated in decapods, suggesting correlated evolution. The analysis showed that species which inhabit environments with intense salinity variation such as estuaries, supratidal and mangrove habitats, all undergo selective pressure to acquire efficient hyper-hyporegulatory mechanisms, aided by low permeabilities. Therefore, hyporegulation can be observed in any colonization route that passes through environments with extreme variations in salinity, such as estuaries or brackish water.

On the penaeid shrimps of the genus Parapenaeopsis Alcock, 1901 (Crustacea, Decapoda) from Taiwan

Five species in the penaeid shrimp genus Parapenaeopsis Alcock, 1901 are reported from Taiwan. Parapenaeopsis amicus V.C. Nguyn, 1971 and P. venusta De Man, 1907 are formally recorded in Taiwan for the first time. Taxonomic problems related to the species reported from Taiwan are discussed, and a key to the species of Parapenaeopsis in Taiwan is provided.

An Authentication Survey on Retail Seafood Products Sold on the Bulgarian Market Underlines the Need for Upgrading the Traceability System

Economically motivated or accidental species substitutions lead to economic and potential health damage to consumers with a loss of confidence in the fishery supply chain. In the present study, a three-year survey on 199 retail seafood products sold on the Bulgarian market was addressed to assess: (1) product authenticity by molecular identification; (2) trade name compliance to the list of official trade names accepted in the territory; (3) adherence of the list in force to the market supply. DNA barcoding on mitochondrial and nuclear genes was applied for the identification of whitefish (WF), crustaceans (C) and mollusks (cephalopods-MC; gastropods-MG; bivalves-MB) except for Mytilus sp. products for which the analysis was conducted with a previously validated RFLP PCR protocol. Identification at the species level was obtained for 94.5% of the products. Failures in species allocation were reconducted due to low resolution and reliability or the absence of reference sequences. The study highlighted an overall mislabeling rate of 11%. WF showed the highest mislabeling rate (14%), followed by MB (12.5%), MC (10%) and C (7.9%). This evidence emphasized the use of DNA-based methods as tools for seafood authentication. The presence of non-compliant trade names and the ineffectiveness of the list to describe the market species varieties attested to the need to improve seafood labeling and traceability at the national level.

Phylogenetic relations and mitogenome-wide similarity metrics reveal monophyly of Penaeus sensu lato

Splitting of the genus Penaeus sensu lato into six new genera based on morphological features alone has been controversial in penaeid shrimp taxonomy. Several studies focused on building phylogenetic relations among the genera of Penaeus sensu lato. However, they lack in utilizing full mitochondrial DNA genome of shrimp representing all the six controversial genera. For the first time, the present study targeted the testing of all the six genera of Penaeus sensu lato for phylogenetic relations utilizing complete mitochondrial genome sequence. In addition, the study reports for the first time about the complete mitochondrial DNA genome sequence of Fenneropenaeus indicus, an important candidate species in aquaculture and fisheries, and utilized it for phylogenomics. The maximum likelihood and Bayesian approaches were deployed to generate and comprehend the phylogenetic relationship among the shrimp in the suborder, Dendrobranchiata. The phylogenetic relations established with limited taxon sampling considered in the study pointed to the monophyly of Penaeus sensu lato and suggested collapsing of the new genera to a single genus. Further, trends in mitogenome-wide estimates of average amino acid identity in the order Decapoda and the genus Penaeus sensu lato supported restoration of the old genus, Penaeus, rather promoting the creation of new genera.