Distribution
Near the town of Santa Rosa in the Cordillera del Condor, northwestern Peru, 950 – 1250 m elevation. View type locality in Google Maps.

Natural History
This species is Peru’s only large-sized member of the Dendrobatinae . It is restricted to dry scrub forest which is unfortunately surrounded by human settlements, resulting in catastrophic habitat degradation for this species. There are only 3 known sites remaining where populations are stable. One is a large cliff containing many bromeliads (around 1100 m elevation), and the other site is a remnant forest containing large Aechmea nudicaulis bromeliads. This beautiful forest has almost entirely been destroyed from fires and logging, and the few hectares that are left could be counted on one hand. These Aechmea-holding forests, which the E. mysteriosus are using, are between 978 and 1250 m elevation. High temperatures by day (35 C) and cold by night (16 C) are the typical conditions in this area. This frog seems to use bromeliads to help maintain a stable temperature. The large rock-bromeliads provide lots of water and work like an umbrella by day. The Aechmea in the trees provide less water, but because of their deep, slender shape, stay relatively cool. The humidity is very low in this area, around 40%.

Conservation Status
The three ‘stable’ biotopes of this frog have been bought by IUCN, a Dutch conservation organization. Two of these habitats hold a population of less then 200 specimens. To be sure this frog will survive in future, more potential habitat should be protected. The old-growth trees with Aechmea are very rare, and have been mostly destroyed. Smuggling took its toll on the small populations in the late 90s, putting them at even more risk than they already were. This is now a somewhat common frog in Europe, completely of illegal origin, and the potential for local conservation projects based on the sale of legal mysteriosus is now severely compromised.

Notes
The original description of Dendrobates mysteriosus was in 1982 by Charles W. Myers. The description was based on a juvenile specimen of 17.6 mm, which had been caught in July 1929 by geologist Harvey Bassler. Myers described the species in that time as a member of a new group, the captivus group. Rainer Schulte rediscovered this species in the late 80s and published a formal redescription in 1990. Schulte vehemently rejected Myers’ hypothesis that E. captivus and E. mysteriosus were closely related. Recent analyses using molecular data suggest that these species are in fact close relatives and form a clade sister to Ranitomeyaplus Andinobates.