Graneledone boreopacifica

DWhatley

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Deep-Sea Octopus (Graneledone boreopacifica) Conducts the Longest-Known Egg-Brooding Period of Any Animal Bruce Robison, Brad Seibel,Jeffrey Drazen 2014 (full article)

Abstract
Octopuses typically have a single reproductive period and then they die (semelparity). Once a clutch of fertilized eggs has been produced, the female protects and tends them until they hatch. In most shallow-water species this period of parental care can last from 1 to 3 months, but very little is known about the brooding of deep-living species. In the cold, dark waters of the deep ocean, metabolic processes are often slower than their counterparts at shallower depths. Extrapolations from data on shallow-water octopus species suggest that lower temperatures would prolong embryonic development periods. Likewise, laboratory studies have linked lower temperatures to longer brooding periods in cephalopods, but direct evidence has not been available. We found an opportunity to directly measure the brooding period of the deep-sea octopus Graneledone boreopacifica, in its natural habitat. At 53 months, it is by far the longest egg-brooding period ever reported for any animal species. These surprising results emphasize the selective value of prolonged embryonic development in order to produce competitive hatchlings. They also extend the known boundaries of physiological adaptations for life in the deep sea.
MBARI news release

 
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DWhatley

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#4


Warts and All: Octopus' Skin Bumps Divide Species
By Mindy Weisberger, Senior Writer | June 7, 2017

wo species of highly similar deep-sea octopuses are hard to tell apart — unless you look closely at their "warts," a new study finds.

Octopuses in the Graneledone genus are pink and pebbly, with trademark bumps on the skin of their mantles — the bulbous body part resembling a head. Taxonomists have traditionally used the number of warts to differentiate between the species Graneledone pacifica, which lives in the Pacific Ocean, and Graneledone verrucosa, an inhabitant of the Atlantic Ocean. But with limited access to specimens, these warty distinctions didn't always hold up across larger numbers of octopuses, the study authors wrote.

This new investigation, in which scientists analyzed 72 octopuses, is the first to comprehensively examine dozens of G. pacifica and G. verrucosa specimens to determine what about these warts really distinguishes the two octopus species — and the scientists conducted their analysis one wart at a time.
...
The researchers gathered their dozens of specimens representing the two species, and hunkered down to count warts. They devised a new method for tracking the distribution of bumps, and eventually pinpointed two characteristics that were consistent across individuals in a given species — how far the warts extended to the tip of the mantle and how far they spread down the arms, Voight said.
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DWhatley

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#5
Towards species identification of the bathyal octopod Graneledone (Mollusca: Cephalopoda)
Janet R. Voight, Jessica A. Kurth 2017 (full article)
Abstract
The number of skin warts has traditionally been cited as a means of separating species in the benthic octopod genus Graneledone, but species-level taxonomy has been problematic since the discovery of a second population. We investigated whether the distribution of skin warts can simply and reliably distinguish similar species by comparing North-east Pacific specimens of Graneledone and North-west Atlantic specimens of G. verrucosa. Two characters, the presence/absence of warts at the posterior tip of the dorsal mantle and the position of the most distal arm wart quantified by the arm sucker number, separate the species. The absence of warts from the distal arms, the third arm pair, and from the lateral web (Sector C) appears to separate these species from congeners based on literature information. Wart distribution may effectively distinguish species throughout the genus, accomplishing the necessary first step in furthering our knowledge of deep-sea biodiversity and reconstructing phylogenetic relationships.
 

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