A new species of Benthoctopus Grimpe, 1921 (Cephalopoda: Octopodidae) from the southeastern Pacific Ocean

A molecular sequence proxy for Muusoctopus januarii and calibration of recent divergence among a group of mesobenthic octopuses

“…4), by contrast, have far less annual rainfall and are currently home to two respective vicariant subspecies of M. longibrachus. Muusoctopus l. longibrachus occurs to around 35°S below 400 m (Gleadall et al, 2010;Ibáñez et al, 2006). Other species occur to the north of this region, at depths of 150-520 m in cold, well oxygenated water (Villarroel et al, 2001).…”

“…Among the cold-water Octopodidae is a group of species ranging in depth from shallower waters on cold temperate continental shelves to mesobenthic and upper bathybenthic regions of continental slopes and seamounts (Allcock et al, 2006;Collins et al, 2001;Gleadall et al, 2010;Hoyle, 1885aHoyle, , 1885bIbáñez et al, 2006;Massy, 1907Massy, , 1909Norman et al, 1997;O'Shea, 1999;Robson, 1929Robson, , 1932Strugnell et al, 2011;Toll, 1981;Vecchione, 2004;Vecchione et al, 2009;Voss, 1956Voss, , 1968Voss and Pearcy, 1990). Continental slope regions are far more stable for sustaining populations than the abyssal plain (Rex et al, 2005), which may help to explain why these species are distributed typically within the upper 1500-2000 m, rarely below 3000 m (see for example, Strugnell et al, 2011).…”

“…Another hypothesis is proposed to explain the distribution of the two South American subspecies of Muusoctopus longibrachus (Ibáñez, Sepúlveda and Chong, 2006) at vicariant localities in the Magellan Region, a separation proposed to have occurred as a result of adverse climatic and geophysical conditions during the last glaciation in South America and the subsequent deglacial period. The approximate dates of these two vicariance events can be used to estimate the rate of recent divergence of several species of Muusoctopus for which Table 1 Material identified as Muusoctopus januarii (Hoyle, 1885) " " " Good a The label with this specimen states that it has a mantle length of 66 mm but was presumably measured before fixation because the present dorsal mantle length is only 40 mm (which is in agreement with NSMZ records for this specimen).…”

“…It is therefore here proposed that sequence data from M. normani can be used as a proxy for M. januarii. It is also proposed that the ancestors of M. januarii walked through the Atrato Seaway into the Atlantic before the rise and completion of the Panamanian Isthmus; and that M. longibrachus (Ibáñez, Sepúlveda and Chong, 2006) was separated into two allopatric populations around the time of the Last Glacial Maximum to form the dichopatric pair of subspecies now extant in the Magellan Region off southern South America. The timing of these two vicariance events provides a means of calibrating the recent divergence rate in the Muusoctopus group, which appears to be at least two to three times faster than reported previously.…”

Morphological and molecular description of a new record of Graneledone (Cephalopoda, Octopodidae) in the southeastern Pacific Ocean

“…Among this fauna, mollusks are one of the most important groups, with about 30 species present. In addition to common cephalopods (sepiolids and squids), unidentified incirrate octopod species belonging to Muusoctopus Gleadall 2004 (formerly Benthoctopus) and Graneledone genus occur it the CMSA and adjacent areas (Ibáñez et al 2006(Ibáñez et al , 2009(Ibáñez et al , 2011.…”