بطمونينات

Dorsal. Specimen ID: 7445007. Field no.: Np1. Taxon rep.: Neolarnaudia. Image quality: 1. Aspect ratio: 1.588.

Dorsal. Specimen ID: 7445016. Field no.: Hx1. Taxon rep.: Hainanpotamon. Image quality: 1. Aspect ratio: 2.299.

Dorsal. Specimen ID: 7445024. Field no.: Lk. Taxon rep.: Laevimon. Image quality: 1. Aspect ratio: 1.011.

Dorsal. Specimen ID: 7444948. Field no.: Tw2.1. Image quality: 1. Aspect ratio: 1.504.

Dorsal. Specimen ID: 3737080. Field no.: TM12-KOU2. Taxon rep.: Potamonautes. Image quality: 4. Aspect ratio: 1.333.

Kunigami, Okinawa, Japan

The freshwater crab genus Nanhaipotamon is endemic to southern China and Taiwan. The taxonomic state of the genus is not entirely understood, as is the distribution of the known species. Many species only exist in a small range, for example N. zhuhaiense, only known from a few hill stream in the city of Zhuhai. Nanhaipotamon guangdongense was described 1997 by Dai from an unknown site in Guangdong province. 2012, Huang et al. found specimens of N. guangdongense living sympatrically with N. zhuhaiense, the first record of the species since 1997.I found this specimen and many more hidden in deep burrows next to small hill streams between 50 and 300 m above sea level in a subtropic hill forest. Adults left their burrows only at night, stayed near the entrance but only went back when approached directly (30 cm distance). N. zhuhaiense was not found at any of the visited sites. Zhuhai, Guangdong.

The freshwater crab genus Nanhaipotamon is endemic to southern China and Taiwan. The taxonomic state of the genus is not entirely understood, as is the distribution of the known species. Many species only exist in a small range, for example N. zhuhaiense, only known from a few hill stream in the city of Zhuhai. Nanhaipotamon guangdongense was described 1997 by Dai from an unknown site in Guangdong province. 2012, Huang et al. found specimens of N. guangdongense living sympatrically with N. zhuhaiense, the first record of the species since 1997. At some sites in Zhuhai, I found N. guangdongense living in high densities (5 crabs per meter river bank) in self digged burrows next to small hill streams, often with high banks. I observed the majority of crabs staying in or close to their burrows during the day and only leaving at night but staying in close range. Nanhaipotamon species can show a great variability in carapax and claw coloration. The crabs I took photos of on a night walk at two small creeks had a more purpleish blue carapax than those found during a day visit at some other nearby streams, clearly resembling Nanhaipotamon guangdongense coloration ( Compare to: treatment.plazi.org/GgServer/html/01307731FF989932B2B5FE4...). A general revision of the genus in southern China regarding morphology/coloration is yet to be done. Although there is known almost nothing about the distribution of Nanhaipotamon species, they are sold as pets on fish markets in Guangzhou and possibly elsewhere in Guangdong. Internet research showed that there exists quite a crab owner community in southern China, with many enthusiasts collecting specimens themselves. Since they can be sold for up to 30 US Dollars a piece, collectors will not communicate the sites where they found crabs so that nobody can harvest there except them. The impact on wild populations of these crabs is basically unkown and needs to be evaluated immediatley, since crabs as pets are becoming more popular every day. Zhuhai, Guangdong.

The freshwater crab genus Nanhaipotamon is endemic to southern China and Taiwan. The taxonomic state of the genus is not entirely understood, as is the distribution of the known species. Many species only exist in a small range, for example N. zhuhaiense, only known from a few hill stream in the city of Zhuhai. Nanhaipotamon guangdongense was described 1997 by Dai from an unknown site in Guangdong province. 2012, Huang et al. found specimens of N. guangdongense living sympatrically with N. zhuhaiense, the first record of the species since 1997.I found this specimen and many more hidden in deep burrows next to small hill streams between 50 and 300 m above sea level in a subtropic hill forest. Adults left their burrows only at night, stayed near the entrance but only went back when approached directly (30 cm distance). N. zhuhaiense was not found at any of the visited sites. Zhuhai, Guangdong.

The freshwater crab genus Nanhaipotamon is endemic to southern China and Taiwan. The taxonomic state of the genus is not entirely understood, as is the distribution of the known species. Many species only exist in a small range, for example N. zhuhaiense, only known from a few hill stream in the city of Zhuhai. Nanhaipotamon guangdongense was described 1997 by Dai from an unknown site in Guangdong province. 2012, Huang et al. found specimens of N. guangdongense living sympatrically with N. zhuhaiense, the first record of the species since 1997.At some sites in Zhuhai, I found N. guangdongense living in high densities (5 crabs per meter river bank) in self digged burrows next to small hill streams, often with high banks. This specimen I digged out and got pinched pretty badly. Although there is known almost nothing about the distribution of Nanhaipotamon species, they are sold as pets on fish markets in Guangzhou and possibly elsewhere in Guangdong. Internet research showed that there exists quite a crab owner community in southern China, with many enthusiasts collecting specimens themselves. Since they can be sold for up to 30 US Dollars a piece, collectors will not communicate the sites where they found crabs so that nobody can harvest there except them. The impact on wild populations of these crabs is basically unkown and needs to be evaluated immediatley, since crabs as pets are becoming more popular every day. Zhuhai, Guangdong.

All members of the freshwater crab genus Nanhaipotamon live semiterrestically in self-digged burrows at the banks of small streams and rivers. Sometimes, their burrows are directely connected to the neighboring stream or ground water. These burrows are really deep and without proper equipment it is often impossible to dig the crabs out. Because they do not go away far from their burrows and will always flee and hide there when disturbed, it is really hard to catch them at all.

The freshwater crab genus Nanhaipotamon is endemic to southern China and Taiwan. The taxonomic state of the genus is not entirely understood, as is the distribution of the known species. Many species only exist in a small range, for example N. zhuhaiense, only known from a few hill streams in the city of Zhuhai. Nanhaipotamon guangdongense was described 1997 by Dai from an unknown site in Guangdong province. 2012, Huang et al. found specimens of N. guangdongense living sympatrically with N. zhuhaiense, the first record of the species since 1997.At some sites in Zhuhai, I found N. guangdongense living in high densities (5 crabs per meter river bank) in self digged burrows next to small hill streams, often with high banks. This specimen I digged out and got pinched pretty badly. Although there is known almost nothing about the distribution of Nanhaipotamon species, they are sold as pets on fish markets in Guangzhou and possibly elsewhere in Guangdong. Internet research showed that there exists quite a crab owner community in southern China, with many enthusiasts collecting specimens themselves. Since they can be sold for up to 30 US Dollars a piece, collectors will not communicate the sites where they found crabs so that nobody can harvest there except them. The impact on wild populations of these crabs is basically unkown and needs to be evaluated immediatley, since crabs as pets are becoming more popular every day. Zhuhai, Guangdong.

Long Terawan, Sarawak, Malaysia

UPDATE: After reading the recently published article about the new freshwater crab genus Cantopotamon, the crabs I found are certainly Cantopotamon zhuhaiense, described from the exact locality where I found them. Here is the link to this article:zoolstud.sinica.edu.tw/Journals/56/56-41.pdfThe crabs were found in fast to slow-flowing hill streams on altitudes between 50 and 300 meters above sea level. They hide under stones and were occasionally observed leaving the water and climbing rock. At no site C. zhuhaiense was seen thriving sympatrically with the other Potamid I saw, Nanhaipotamon guangdongense, although in the original description, they were observed living in the same habitat as Nanhaipotamon zhuhaiense and N. guangdongense. Nevertheless, N. guangdongense was present in very small to small, more slow-flowing streams with sandy, muddy, or clay bottom, whereas C. zhuhaiense was found in broader, fast-flowing streams on gravel or sandy bottom.Zhuhai, Guangdong Former Text:The freshwater crab genus Candidiopotamon is to date only known from Taiwan and the Ryukyu Islands. The species described from Guangdong province by Dai, 1999 is now considered a synonym of C. rathbunae from Taiwan (See Shih & Ng, 2011).Nevertheless, I found a few specimens resembeling no other Potamids from Guangdong province that I am aware of, but bear similarity to C. rathbunae. For no better name, the specimes are labeled C. cf. guangdongense. It is possible that there is a population of C. rathbunae or a new unknown species in Guangdong. Perhaps, the crabs I found belong to yet another species described by a single or few specimens from unknown localities in Guangdong, as Yarepotamon guangdongense. The only dorsal image of Y. guangdongense I was able to find is in black and white and really small, and as I did not take an image of the male Gonopod or Maxilliped 3, there is no way to finally determine the status of the photographed specimen (link to the article here: lkcnhm.nus.edu.sg/app/uploads/2017/06/45rbz237-264.pdf).

UPDATE: After reading the recently published article about the new freshwater crab genus Cantopotamon, the crabs I found are certainly Cantopotamon zhuhaiense, described from the exact locality where I found them. Here is the link to this article:zoolstud.sinica.edu.tw/Journals/56/56-41.pdfThe crabs were found in fast to slow-flowing hill streams on altitudes between 50 and 300 meters above sea level. They hide under stones and were occasionally observed leaving the water and climbing rock. At no site C. zhuhaiense was seen thriving sympatrically with the other Potamid I saw, Nanhaipotamon guangdongense, althuogh in the original description, they were observed living in the same habitat as Nanhaipotamon zhuhaiense and N. guangdongense. Nevertheless, N. guangdongense was present in very small to small, more slow-flowing streams with sandy, muddy, or clay bottom, whereas C. zhuhaiense was found in broader, fast-flowing streams on gravel or sandy bottom.Zhuhai, Guangdong Fromer Text:The freshwater crab genus Candidiopotamon is to date only known from Taiwan and the Ryukyu Islands. The species described from Guangdong province by Dai, 1999 is now considered a synonym of C. rathbunae from Taiwan (See Shih & Ng, 2011).Nevertheless, I found a few specimens resembeling no other Potamids from Guangdong province that I am aware of, but bear similarity to C. rathbunae. For no better name, the specimes are labeled C. cf. guangdongense. It is possible that there is a population of C. rathbunae or a new unknown species in Guangdong. Perhaps, the crabs I found belong to yet another species described by a single or few specimens from unknown localities in Guangdong, as Yarepotamon guangdongense. The only dorsal image of Y. guangdongense I was able to find is in black and white and really small, and as I did not take an image of the male Gonopod or Maxilliped 3, there is no way to finally determine the status of the photographed specimen (link to the article here: lkcnhm.nus.edu.sg/app/uploads/2017/06/45rbz237-264.pdf).

Kunigami, Okinawa, Japan

The freshwater crab fauna of China is incredibly diverse, containing many highly endemic species with a restricted ranges. One of the rarest species is Daipotamon minos, a cavernicolous species from La Tai Dong cave. The species was discovered 1996 and is so far only known from the type locality, a small river inside a karstic cave. There is no light where the crabs live although they do not seem to have adapted morphologically to the cave as a habitat, still having fully pigmented eyes and a dark brown carapax and light brown walking legs.During my visit, I only found 3 specimens, two juveniles and one adult, and they are not at all abundant inside the cave. However, the cave is rarely visited by locals and by its natural constitution well protected from habitat alteration. A future problem could be pestecides and fertilizer in the river water, which would be definitely worth studying.Adult crab, Libo, Guizhou.Further information:Ng, P.K.L. & Trontelj, P. 1996. Daipotamon minos, a new genus and species of potamid crab (Crustacea: Decapoda: Brachyura) from a cave in China. Proceedings of the biological society of Washington 109(3): 476 - 481

The freshwater crab fauna of China is incredibly diverse, containing many highly endemic species with a restricted ranges. One of the rarest species is Daipotamon minos, a cavernicolous species from La Tai Dong cave. The species was discovered 1996 and is so far only known from the type locality, a small river inside a karstic cave. There is no light where the crabs live although they do not seem to have adapted morphologically to the cave as a habitat, still having fully pigmented eyes and a dark brown carapax and light brown walking legs.During my visit, I only found 3 specimens, two juveniles and one adult, and they are not at all abundant inside the cave. However, the cave is rarely visited by locals and by its natural constitution well protected from habitat alteration. A future problem could be pestecides and fertilizer in the river water, which would be definitely worth studying.Adult crab, Libo, Guizhou.Further information:Ng, P.K.L. & Trontelj, P. 1996. Daipotamon minos, a new genus and species of potamid crab (Crustacea: Decapoda: Brachyura) from a cave in China. Proceedings of the biological society of Washington 109(3): 476 - 481

The freshwater crab fauna of China is incredibly diverse, containing many highly endemic species with a restricted ranges. One of the rarest species is Daipotamon minos, a cavernicolous species from La Tai Dong cave. The species was discovered 1996 and is so far only known from the type locality, a small river inside a karstic cave. There is no light where the crabs live although they do not seem to have adapted morphologically to the cave as a habitat, still having fully pigmented eyes and a dark brown carapax and light brown walking legs.During my visit, I only found 3 specimens, two juveniles and one adult, and they are not at all abundant inside the cave. However, the cave is rarely visited by locals and by its natural constitution well protected from habitat alteration. A future problem could be pestecides and fertilizer in the river water, which would be definitely worth studying.Adult crab, Libo, Guizhou.Further information:Ng, P.K.L. & Trontelj, P. 1996. Daipotamon minos, a new genus and species of potamid crab (Crustacea: Decapoda: Brachyura) from a cave in China. Proceedings of the biological society of Washington 109(3): 476 - 481

Plakias, Crete, Greece

Plakias, Crete, Greece

Until now, the semi-terrestically freshwater crab Nanhaipotamon hongkongense was due to lack of better distribution knowledge considered a Hong Kong endemic. During a night walk in Shenzhen, however, I found crabs resembling the phenotype of N. hongkongense, so this species is most probably distributed in the southern parts of Guangdong, as well. Other than N. guangdongense, which was abundant and not too hard to observe at some sites in Zhuhai, I was not able to find a site where N. hongkongense was similarly abundant. The crabs tend to flee and hide in their burrows at the slightest disturbance and may therefore be more cryptic than allied species in southern China. Of all Nanhaipotamon species, N. hongkongense is the most traded in pet markets even in Europe because of its variable and signalling red or orange colour and vivid behaviour.Collections of wild animals may pose a threat to current populations in Hong Kong. This and a cryptic life history may be the reason why they did not seem to be as abundant as N. guangdongense.Wutong Shan, Shenzhen, China.