A new crab: Harryplax severus

Credit: Jose C. E. Mendoza

The crab family Christmaplacidae has only been recently described (2014) and so far comprised one species found in an underwater cave at Christmas Island hence the name. Now a new crab from a different Pacific region was added to this family.

The new species is a tiny crab measuring less than a centimeter in both length and width and can be found deep in coral rubble or under subtidal rocks, perhaps also in cavities. To survive in the dark depths, the species has evolved with reduced eyes, well developed antennae, and long, slender legs. For the time being it is known only from the island of Guam.

The new genus is named primarily in honor of the field collector Harry T. Conley, who collected many interesting crustaceans in the rubble beds of Guam, including the new species. The name is also an allusion to a famous namesake, Harry Potter. The species name severus is an allusion to a notorious and misunderstood character in the Harry Potter novels, Professor Severus Snape, for his ability to keep one of the most important secrets in the story, just like the new species which has eluded discovery for nearly 20 years after being collected first. 

For the experts: Harryplax severus, a new genus and species of coral rubble-dwelling pseudozioid crab is described from the island of Guam in the western Pacific Ocean. The unusual morphological features of its carapace, thoracic sternum, eyes, antennules, pereopods and gonopods place it in the family Christmaplacidae Naruse & Ng, 2014. A suite of characters on the cephalothorax, pleon and appendages distinguishes H. severus gen. & sp. n. from the previously sole representative of the family, Christmaplax mirabilis Naruse & Ng, 2014, described from Christmas Island in the eastern Indian Ocean. This represents the first record of Christmaplacidae in the Pacific Ocean. With the discovery of a second genus, a revised diagnosis for Christmaplacidae is provided.