Notes on two rare species of brachyuran crabs (families Matutidae and Parthenopidae) from Indonesian waters with new distribution records

This research aimed to report two species of Brachyuran crabs that were found rarely from Indonesian waters. The latest report was more than one hundred years ago, and the study from Indonesia before was not so clear, both information about specimens and location details. We conducted our study in Southern Aru Island and Malacca Strait using trawl during the cruise research which was held by the Research Institute for Marine Fisheries, Ministry of Marine Affairs and Fisheries. Our findings were Izanami reticulata, New Record (family Matutidae) from Southern Aru Island, and Cryptopodia fornicata (family Parthenopidae) from Malacca Strait. The two locations are located close to the location where the species was found in previous studies, namely the Arafura Sea which is adjacent to the Aru Islands, and the Malacca Strait which is adjacent to Borneo. We suspect that the presence of these two species in western and eastern Indonesia was due to their distribution during the pelagic larval stage through the sea current. This article also provided the specific habitat for both species which has not been stated. In addition, this article will contribute to strengthening Indonesia as a mega biodiversity country with initiate compiling the database of Brachyura in Indonesian waters.

Updated checklist of semi-terrestrial and estuarine crabs (Crustacea: Decapoda: Brachyura) of Barbados, West Indies

Considering the growing threats to the biodiversity of small Caribbean islands (e.g., habitat loss and fragmentation, overexploitation, invasive species, and climate change), it is important to establish biodiversity inventories that serve as baselines for monitoring and evaluation of conservation efforts. In Barbados (West Indies), the most recent comprehensive taxonomic account of brachyuran crabs came from Rathbun (1921) reporting the specimens collected by the University of Iowa Barbados-Antigua Expedition in 1918. The present study fills the 100-year gap in knowledge by providing an updated taxonomic checklist of brachyuran crabs associated with semi-terrestrial and estuarine habitats in Barbados. A total of 245 specimens representing three superfamilies, six families, nine genera, and 13 species were collected over a period of 425 search-hours in twenty-seven sampling locations in semi-terrestrial and estuarine habitats of Barbados between September 2018 and November 2020. The families with the highest numbers of species identified were Gecarcinidae (3) and Portunidae (3), followed by Grapsidae (2), Sesarmidae (2), Ocypodidae (2), and Varunidae (1). The species Armases ricordi (H. Milne Edwards, 1853), Cyclograpsus integer H. Milne Edwards, 1837, and Callinectes sapidus Rathbun, 1896, are recorded here for the first time for Barbados.

A DNA barcode library for mangrove gastropods and crabs of Hong Kong and the Greater Bay Area reveals an unexpected faunal diversity associated with the intertidal forests of Southern China

Background Mangroves are tropical and subtropical intertidal forests colonising sheltered coasts across the world. They host a unique faunal community, dominated by brachyuran crabs and gastropods. These invertebrates strongly contribute to the functionality of the entire forest. The reliable assessment of mangrove faunal diversity is, thus, a crucial step for efficient management and conservation plans, but it is hindered by difficulties in species identification. Here we provide a verified DNA barcode library for brachyuran crabs and gastropods inhabiting the mangroves of the Greater Bay Area, Southern China. In particular, we collected and morphologically identified 1100 specimens of mangrove associated brachyuran crabs and gastropods. The partial sequences of the mtDNA cytochrome oxidase subunit I gene were obtained from 275 specimens. Barcode sequences were then used to delineate Molecular Operational Taxonomic Units (MOTUs), employing three different delimitation methods: the automatic barcode gap discovery (ABGD) method, the general mixed Yule coalescent (GMYC) model and a Bayesian implementation of the Poisson tree processes (bPTP) model. Results By integrating DNA barcodes with morphology, we identified 44 gastropod species and 58 brachyuran species associated with Hong Kong mangroves, with five and seven new records, for gastropods and crabs, respectively, for the Greater Bay Area. The delineation of MOTUs based on barcode sequences revealed a strong congruence between morphological and molecular identification for both taxa, showing the high reliability of the barcode library. Conclusions This study provides the first reference barcode library for mangrove-associated macrobenthic fauna in the Greater Bay Area and represents a reliable tool to management and conservation plans. Our molecular analyses resolved long lasting taxonomic misidentifications and inconsistencies and updated the knowledge on the geographical distribution of Asian mangrove associated fauna, ultimately highlighting a level of biodiversity higher than previously thought for Southern China.

Toxicity of petroleum hydrocarbons to Brachyuran crabs: a review of deleterious effects of oil-related xenobiotics on life stages

Petroleum hydrocarbons (PH) toxicity and bioaccumulation in aquatic organisms have been investigated for almost 50 years. Continuous oil spillages necessitate a further understanding of the toxicological effects of PH on brachyuran crabs. Crabs can be exposed to PH through various routes such as the water column, sediment and diet. Numerous investigations have been dedicated to evaluating PH toxicity on different life stages of crab species, but the majority of them have focused on the blue crab Callinectes sapidus as it represents an edible and favourable seafood commodity for human consumption. The objective of the review is to critically assess studies related to PH toxicity on different life stages of 41 crab species representing 13 families across the world. Several physiological, biochemical and genetic endpoints of marine crabs were evaluated in addition to the sublethal effects of PH on crab metabolism, behaviour, moulting, growth and survival. A concise summary of PH deleterious effects on different taxonomic species of marine crabs is discussed and provides evidence that crabs can be used as indicator organisms of biomarker significance for marine pollution. Overall, larval stages appeared to be the most sensitive to the deleterious effects of PH compared with juveniles and adults. However, adult stages have received more research attention than other life stages, followed by larval stages, and juvenile stages are the least investigated stages with respect to PH toxicity. Finally, hepatopancreas and gills were the organs where greatest accumulation of PH was recorded.