Rediscovery after 25 years – first photographic documentation and DNA barcoding of the deep-sea pycnogonid species Ascorhynchus hippos Turpaeva, 1994 (Chelicerata, Pycnogonida, Ascorhynchidae) from the Kuril-Kamchatka Trench

The female specimen of Ascorhynchus hippos Turpaeva, 1994 was collected in 2015 during the Russian-German deep-sea expedition SokhoBio (Sea of Okhotsk Biodiversity Studies) at the abyssal western slope of the Kuril-Kamchatka Trench at a depth of 4469 m using a camera-epibenthic sledge. It is the first record of this species since the discovery of one female holotype and one male paratype in 1990. Ascorhynchus hippos is easily distinguishable from its congeners by the two prominent tubercles above the chelifore insertions, the absence of the eye tubercle and eyes, and the tubercles on the mid-dorsal trunk segments and the lateral processes. Here we present the first photographic documentation of all three known specimens of A. hippos and the COI barcode of the new specimen is also provided.