Species Diversity of Marine Bivalves from the Strait of Rupat Island Riau Province, Indonesia

A survey of marine bivalves for species diversity was conducted at five locations in the current study; Three stasiun at Dumai city beach those are Silensing, Bandar Bakau, Basilam Baru, Sri Tanjung, and Pulau Payung beach of Rupat Island Strait, Riau Povince. Indonesia. The goal of this study was to learn more about the marine bivalves that live in the Rupat Island strait. From July to August 2020, marine bivalves were collected during spring low tides from intertidal zones and shallow coastal waters. From the Strait of Rupat Island, 13 bivalves belonging to 11 genera, 11 families and 8 orders were discovered. During the research, bivalves from the families Pectinidae, Placunidae, Arcidae, Trapezidae, Veneridae Ostreidae, Corbiculidae, and Psammobiidae were recorded during the study. The number of bivalves in each family reveals that two species belongs to the Arcidae family and two to the Cyrenidae family. Corbiculidae, Placunidae, Trapezidae, and Psammobiidae each had one species reported. The abundance of each species found was extremely low, it is not feasible to be presented quantitatively. The most common species encountered in the strait were Anadara granosa, Polymesoda erosa, Polymesoda expansa, and Pharella acutidens. The anthropogenic activities of Dumai city and Rupat Island, such as the discharge of industrial wastes, residential sewage, overfishing, habitat loss, overharvesting and tourism, could cause variations in bivalves abundance in the Strait of Rupat Island.

On the Alber equation for shoaling water waves

The problem of unidirectional shoaling of a water-wave field with a narrow energy spectrum is treated by using a new Alber equation. The stability of the linear stationary solution to small non-stationary disturbances is analysed; and numerical solutions for its subsequent long-distance evolution are presented. The results quantify the physics which causes the gradual decay in the probability of freak-wave occurrence, when moving from deep to shallow coastal waters.

Cephalopoda (Mollusca) of the Colombian Caribbean Sea

The cephalopod fauna in Colombian Caribbean waters is poorly known. This work gives an overview of the species found in the area. For elaborating this list, the most relevant natural history collections where the material of the area’s is material is deposited were consulted, identifications were verified compared with type material and original descriptions and redescriptions. In the Colombian Caribbean Sea 48 cephalopod species are present in different environments, represented in 17 families and 33 genera. There is one Spirula, seven sepiolids, 21 squids, and 19 octopod species. Most animals are from shallow coastal waters.

Tritodynamia bengalensis n. sp., a new species of brachyuran crab from West Bengal state, India (Decapoda: Brachyura: Macrophthalmidae)

Tritodynamia bengalensis n. sp. is described on the basis of a male specimen dredged from the shallow coastal waters of West Bengal state, India. The new species is morphologically similar to T. bidentata Yang & Tang, 2005 and T. serratipes Anker & Ng, 2014, but can be distinguished by the carapace shape, dentition of the pollex, relative length of the dactylus of the third maxilliped, proportions of the propodus of the third pereopod, and structure of the male left gonopod. This is the first record of the genus Tritodynamia from India.