Tag: crustaceans

New species of pea-size crab parasitizing a date mussel has a name of a Roman god

Tiny crabs, the size of a pea, dwell inside the mantles of various bivalves, living off the food filtered by their hosts. A new species of these curious crustaceans has recently been reported from the Solomon Islands, where an individual was found to parasitise a large date mussel.

Because of the new pea crab’s characteristic large additional plate, covering its upper carapace, giving it the illusion of having two faces, it has been named after Janus, the Roman two-faced god. Discoverers Dr Peter Ng, National University of Singapore, and Dr Christopher Meyer, U.S. National Museum of Natural History, Smithsonian Institution, have their findings published in the open access journal ZooKeys.

Being only the second species in the genus (the first was from Malaysia), the new pea crab Serenotheres janus can be distinguished by its broader carapace and other features. It is cream-yellow in colour.oo_106009

Both representatives of the genus are unique in having an additional large plate covering the upper side of the carapace. However, its purpose is still unknown. The two pea crabs are also the only known parasites of the rock-boring bivalves of the mytilid subfamily Lithophaginae.

###

Original source:

Ng PKL, Meyer C (2016) A new species of pea crab of the genus Serenotheres Ahyong & Ng, 2005 (Crustacea, Brachyura, Pinnotheridae) from the date mussel Leiosolenus Carpenter, 1857 (Mollusca, Bivalvia, Mytilidae, Lithophaginae) from the Solomon Islands. ZooKeys 623: 31-41. doi: 10.3897/zookeys.623.10272

Crab from the Chinese pet market turns out to be a new species of a new genus

Shimmering carapaces and rattling claws make colourful freshwater crabs attractive to pet keepers. To answer the demand, fishermen are busy collecting and trading with the crustaceans, often not knowing what exactly they have handed over to their client.

oo_102037Luckily for science and nature alike, however, such ‘stock’ sometimes ends up in the hands of scientists, who recognise their peculiarities and readily dig into them to make the next amazing discovery. Such is the case of three researchers from University of New South Wales, Australia, The Australian Museum, Sun Yat-sen University, China, and National Chung Hsing University, Taiwan, who have found a new species and even a new genus of freshwater crab, and now have it published in the open access journal ZooKeys.

Knowing about the growing demand for eye-catching freshwater crabs from southern China, the authors took a look at the ornamental fish market to eventually identify an individual with unusually structured male gonopod, which in crustaceans is a swimming appendage modified to serve as a reproductive organ. Having their interest drawn by the peculiar crab, lead author Chao Huang managed to persuade the fish dealer to let them survey the collection site located in northern Guangdong, southern China.

Despite superficial resemblance to an already existing freshwater crab genus, at second glance, the crab turned out to be quite distinct thanks to a unique set of features including the carapace, the gonopod and the relatively long and slender legs. Once the molecular analyses’ results were also in, the authors had enough evidence to assign the freshwater crab as a species and even a genus new to science.

oo_102036Being a primarily aquatic species, the new crab prefers the pools of limestone hillstreams, therefore its name Yuebeipotamon calciatile, where calciatile means ‘living on limestone’. To adapt to the habitat, the species seems to have developed its characteristic slender legs, which make it easier for the crab to climb and move around whenever the short-lived limestone hillstreams make it search for a new home.

The carapace of the new crab is usually coloured in maroon to dark brown, while the claws and legs are reddish to purplish. Interestingly, the adults are much more vivid compared to the juveniles.

###

Original source:

Citation: Huang C, Shih H-T, Mao SY (2016) Yuebeipotamon calciatile, a new genus and new species of freshwater crab from southern China (Crustacea, Decapoda, Brachyura, Potamidae). ZooKeys 615: 61-72. doi: 10.3897/zookeys.615.9964

Underground gourmet: Selected terrestrial cave invertebrates and their meal preferences

Doubting whether terrestrial cave invertebrates feed on just anything they can find in the harsh food-wise environment underground, Dr. Jaroslav Smrz, fromCharles University, Vinicna, and his international team conducted a research in Slovakian and Romania caves. They tested the hypothesis that these species have rather negligible selection of food. Their microanatomical research into the gut content of several microwhip scorpions, oribatid mites, millipedes, springtails and crustaceans showed, however, that there is an evident meal preference among the species.

The results confirmed that the studied groups can adapt and develop under the pressure of extreme environmental factors. Therefore, the researchers concluded a low level of food competition. The study is available in the Subterranean Biology open-access journal.

The scientists studied the cells and tissues of the selected invertebrates and found out that the gut contents were nearly identical between the representatives of each group. This was the case even when the specimens had been collected from various locations. For instance, all microwhip scorpions proved a preference for cyanobacteria, while the mites favored the bacteria found in bat guano and the millipedes – fungi.

“The limited food offer seems to be used very unambiguously and thoroughly by the invertebrate communities,” the research team explained. “Therefore, the competition for food can be actually regarded as very low,” they concluded.

###

Original source:

Smrz J, Kovac L, Mikes J, Sustr V, Lukesova A, Tajovsky K, Novakova A, Reznakova P (2015) Food sources of selected terrestrial cave arthropods. Subterranean Biology 16: 37-46. doi:10.3897/subtbiol.16.8609