The water mite family Pontarachnidae Koenike, 1910, the only family of the Hydrachnidia occurring in the marine environment, represents a diverse and widespread, but still neglected group of marine meiofauna. Most marine species live nearshore with the exception of few freshwater species found in estuaries or locations near the sea (Smit 2002; Smit & Alberti 2010). In this paper we describe a new species, Pontarachna nemethi, from substrata collected from El Seco, a mesophotic site near Vieques Island off Puerto Rico, from 52–67 m depth, more than 2 times the depth at which Pontarachnidae have been previously collected. The finding of the new species remarkably extended the potential area of the world ocean occupied by the Pontarachnidae.

Depth range
52- 67 m

Mesophotic “mentions”
10 x (total of 1598 words)

Classification
* Presents original data
* Reports new species
* Focused on 'mesophotic' depth range
* Focused on 'mesophotic coral ecosystem'

Fields
Biodiversity
Taxonomy

Focusgroups
Other invertebrates

Locations
Puerto Rico

Platforms
Rebreather