Medium sized round square crab is a species of crab in the family Crabaidae and genus Crabapple. It is distributed in North Korea, the Indian Ocean, and Taiwan Island. This type of crab often inhabits under rocks or between pebbles at the high tide line, and its living environment is seawater. In scientific classification, it belongs to the animal kingdom, arthropod phylum, crustacean subphylum, soft shelled class, Decapoda, Caesarea, short tailed suborder, Crabapple family, and Crabapple genus. The scientific name of this crab was first named by Ortmann in 1894.

Ozawa crab is a freshwater crab belonging to the genus Ozawa. It coexists with Geothelphusa dehaani in river habitats in southern Kyushu, Kagoshima Prefecture, and the Osumi Peninsula in Japan. With G Compared to Dehaani, the maximum body size of the Ozawa crab is smaller and it mainly lives in water (aquatic), while G Dehaani may live both in water and on land (amphibious). The differences in habitat and activity patterns among Geothelphusa species are attributed to their microenvironment and the impact of interspecific competition in symbiosis.

The Sesarma bidens, also known as the Double Toothed Hand Crab, belongs to the family Crabs and the genus Sesarma. The two tooth hand crab is distributed in North Korea, Japan, the Philippines, the Malay Islands, Andaman, Sri Lanka, India, Taiwan Island, as well as Guangxi, Guangdong, Hong Kong, Fujian and other places in the Chinese Mainland. Its living environment is seawater, which is mostly found on mudflats near estuaries and far away from water.

The Four Toothed Large Crab (scientific name: Metopograpsus quadridentatus) is an animal belonging to the genus Large Crab in the family Crabs. It is distributed in Malacca, Java, Balibaban, Kalimantan, New Guinea, the Indian Ocean, and Guangdong, Fujian, Zhejiang, Shandong and other places in Chinese Mainland. Its living environment is sea water, which is mostly found in rock cracks or under rocks at the low tide line.

Chasmaganathus converxus, also known as the long backed open mouth crab, belongs to the family of square crabs. Some individuals have a bright purple color all over their body and red joints, which are easily recognizable, but some individuals have a yellowish color that is very similar to Taiwan thick crabs. Cave dwellings are found around grassy marshes near river mouths, between field ridges, mangrove swamps, and along earthen embankments. There are collection records in both the Jianxing ephedra forest and the Wenliao mangrove forest.

The Geothelphusa dehaani crab (scientific name: Geothelphusa dehaani) is a type of crab classified in the order Shrimp (Decapoda), suborder Crabs, and family Characidae. It is a unique species in Japan, a pure freshwater crab that spends its entire life in freshwater areas. The specific name dehaani in the scientific name is named in honor of the Dutch zoologist Wilhelm de Haan, who made contributions to the classification of crustaceans in Japan.

Chiromantes dehaani, formerly known as Chiromantes dehaani, originally belonged to the family Characidae and genus Chiromantes. After separating from the family Characidae, Chiromantes dehaani was reclassified as Chiromantes and genus Chiromantes dehaani. It is distributed in Korea, Japan, Taiwan Island, Hainan Island, Guangdong, Fujian, Zhejiang, Jiangsu, Liaodong Peninsula and other places in Chinese Mainland, and generally lives on the muddy banks of offshore freshwater rivers or in offshore marshes. It is the second intermediate host of mouse lung flukes.

The anthropomorphic crab is a species of crab in the anthropomorphic crab family, also known as the carrier crab. It occurs in the eastern Atlantic and Mediterranean, from Angola to Norway, the Northern Islands, and Iceland. It is benthic and occurs at depths of 10-1212 meters, but is mainly found at depths exceeding 80 meters. It prefers areas with soil and emerging rocks, and has been observed in deep-water coral gardens and sponge gathering areas.

Red eyed snow crab, also known as Bai's snow crab or long footed crab, is a type of snow crab. It is very similar to the gray eyed snow crab and is both found in the Bering Sea. The difference is that it is only found in the northern Pacific Ocean and is commonly referred to as the "snow crab" when sold. In the United States, it is also known as the cobbler crab, and in Japan, it is also known as the Great Chu crab or the big headed dwarf crab. Due to overfishing, the population of red eyed snow crabs has significantly decreased.

Platycodon grandiflorus, commonly known as orange mud crab, is a species of important commercial value in the mangrove crab genus. It is one of several crabs known as mud crabs, distributed in mangrove areas from Southeast Asia to Pakistan, from Japan to northern Australia. Like other species in the Scylla genus, it is widely cultivated using wild caught populations in aquaculture.

The red clawed hand crab is an arthropod belonging to the family Tetraodontidae in the order Decapoda. The width of the head and chest armor is slightly larger than its length, square in shape, and has a smooth surface. Wide forehead, straight leading edge, sharp ridge behind forehead; The outer eye socket is triangular in shape; Sharp and toothless edges. Steps 1-4: The last 3 segments of the foot have black hard bristles; Abdominal triangle, tail segment nearly circular. Male claws are larger than females, with high palmar nodes and granular dorsal edges. The middle of the inner side has granules, while the outer side is smooth and often blood red in color; The gap between the two fingers of the male claw is larger than that of the female claw, and the inner edges of the two fingers are serrated, with one larger tooth at each end. The female abdomen is round and large.

Macrophthalmus banzai (scientific name: Macrophthalmus banzai) is an animal belonging to the genus Macrophthalmus in the family Macrophthalmidae of the sand crab superfamily. The eye sockets are long, the eye stalks are slender, the palms are long, and the two directions are bent downwards. The fingertips are spoon shaped, and the whole body is earthy brown, but the color of the sting is relatively light. When hidden in water, the slender eyes stand upright and protrude from the water surface, and male big eyed crabs have the habit of swinging their double stings, so they are also known as "long live big eyed crabs". Distributed in Japan, Taiwan, China, Hong Kong and Shandong