[Encounters] Identifying Stranded Cephalopods

[DWhatley]

This thread will try to collect articles and references to help identify the different species of cephalopods that make their way to news articles.

neurobadger came up with the first one posted on the Smithsonian website:
Key to decapodiform Cephalopod families

Cheerioteuthis PDF from the Smithsonian library:
The Systematics and Areal Distribution of Pelagic Cephalopods from the Seas Off Southern California by RE Young (1972).

 

[mucktopus]

Wow- very cool! Thanks for posting!

 

[Level_Head]

It's almost tougher with octopuses, isn't it?

 

[DWhatley]

neurobadger has mentioned that her summer work suggests squid are easier but I am not sure Kat would agree once you get past the common ones. One observation I have made is that a dead octopus in formalin looks like an octopus. When I have a request for a preserved one, I sometime have difficulty with which ones I have if there are several available (fortunately this has only happened a couple of times, usually I don't have a collection). Species descriptions from dead animals don't help a lot with IDing live ones.

 

[neurobadger]

A dead octopus looks like An Octopus, whereas a dead Enoploteuthis obliqua looks like a dead Enoploteuthis obliqua .

 

[Cheerioteuthis]

Here's another good one!

The Systematics and Areal Distribution of Pelagic Cephalopods from the Seas Off Southern California by RE Young (1972).
http://si-pddr.si.edu/dspace/bitstream/10088/5117/1/SCtZ-0097-Hi_res.pdf

 

[DWhatley]

Thanks and welcome Cheerioteuthis. As entries are made, I will add them to the first post to keep them visible.

 

[DWhatley]

Archipelagos Library A brief set of descriptions for two of the of the Cuttlefish found in the Mediterranean, Sepia officianalis and Sepia eLegans

 

[GPO87]

I have to admit, that first one can be quite a challenge if you don't know what you are looking for. I tried to get it to project a Teuthowenia, and failed miserably!

 

[DWhatley]

GPO87,
I would be helpful if they would present a highlilghted list all the species available and then unhighlight the animals that are eliminated as you make choices. Soooo many things we can do that we don't ...

 

[DWhatley]

Octopus Suckers Identification Code (OSIC) - Full Text available
Francesca Tramacereab*, Lucia Beccaia, Michael J. Kubacd & Barbara Mazzolaia

Abstract
In the literature, a reference terminology for labelling octopus arms exists, but a convention for the labelling of octopus suckers is so far lacking. The precise identification and subsequent ability to address a specific sucker is impossible without some type of convention. In this work, we propose an Octopus Sucker Identification Code, with three/five characters, depending on whether the octopus species has one or two rows of suckers. Specifically, two characters identify the arm to which the sucker belongs, one integer identifies the sucker position along the arm and two subscript characters (present in cases of octopus species with two rows of suckers) identify the adjacent arm towards which the sucker is faced. The proposed code allows the unequivocal identification of the suckers of any octopus arm of any octopus species.

The proposed sucker labelling format will be particularly useful in several scientific works dealing with octopus. One example is the study of enlarged suckers as an indicator of male maturity in octopus (Johnsen et al. 19995. Johnsen S, Balser EJ, Widder EA. 1999. Light-emitting suckers in an octopus. Nature. 398:113–114.
[CrossRef], [Web of Science ®], [CSA]
View all references). In this case, the exact localisation of these enlarged suckers would be particularly important to verify whether male maturity is always expressed in the same portion of the arm or, in contrast, in a random way. Another application of our method is in studies of grasping and manipulation (Grasso 20082. Grasso FW. 2008. Octopus sucker-arm coordination in grasping and manipulation. Am Malacol Bull. 24:13–23.
[CrossRef], [Web of Science ®]
View all references). It has been demonstrated that coordination among different suckers exists, and, indeed, it would be particularly interesting to identify exactly which suckers are involved in the interaction.

As a programmer, I will strongly object to the design of this suggested notation as it is not one that is easily stored, typed or referenced. For both typing and data handling, the always present data should be first, followed by the maybe data. The content seems to be well thought out but something more on the order of S34B5L2L3 Where S34 indicates the 34th sucker, B5 a count of the beak area suckers, L2 the 2nd left arm and L3 indicating the adjacent arm. Alternately the row indicator could be solely a letter indicating the side rather than the adjacent arm number. Lower case could be used (S34B5L2l ) in formal presentations and it should not be confusing when hand written since the optional last character can only be blank, l or r.

Octopus, How Do You Count Your Suckers?
Scientific American, Octopus Chronicles 2013/12, Katherine Harmon Courage

Katherine blogs about the above study and proposal.

 

[DWhatley]

The early life history of two sympatric New Zealand octopuses: eggs and paralarvae of Octopus huttoniand Pinnoctopus cordiformis
S A Carrasco 2013 - (subscription)

Abstract
This study combined morphological and morphometric information on egg clutches, egg capsules and paralarvae of two sympatric coastal octopuses from New Zealand waters, Octopus huttoni and Pinnoctopus cordiformis, to provide species-specific traits to identify their early life stages obtained from field surveys. Eggs of O. huttoni (2.5 mm length; 1 mm width) were entwined with one another forming strings that ranged from 11 to 25.8 mm in length. Eggs of P. cordiformis (6.4 mm length; 1.5 mm width) were significantly bigger than those of O. huttoni and were grouped in small clusters of about seven eggs. Paralarvae O. huttoni and P. cordiformis differed in hatching size (1.4 mm versus 3.1 mm mantle length), number of suckers per arm (four versus eight), number of lamellae per outer demibranch (five versus ten) and arrangements of chromatophores in the body surface (29 to 59 versus 91 to 179), respectively. The morphological traits described in hatchlings from the laboratory allowed comparisons with field-collected paralarvae, suggesting that such characters were reliable species-specific patterns to enable a consistent differentiation between the early life stages of these two sympatric species, even in the absence of the brooding female.

 

[Jean]

For NZ I still go for
The marine fauna of New Zealand: Octopoda (Mollusca:Cephalopoda) (NIWA biodiversity memoir)
by Steve O'Shea sadly not available online but Amazon have it

for the world (it's old but....!)online at FAO species catalogue. Vol.3. Cephalopods of the world. An annotated and illustrated catalogue of species of interest to fisheries

FAO Fisheries Synopsis No. 125, Volume 3

FAO Species Catalogue Vol. 3.
Cephalopods of The World
An Annotated and Illustrated Catalogue of Species of Interest to Fisheries

 

[DWhatley]

Description of the statolith shape of two sympatric ommastrephids in the Mexican Pacific obtained from geometric morphometrics as a tool for identification at the species level
Mariana Díaz-Santana-Iturríos, César A. Salinas-Zavala, Jasmín Granados-Amores 2017 (Marine Biodiversity, Springer subscription)

Abstract
As a contribution to the identification of teuthid species, the objective of this study was to determine the discriminant power of statolith shape using geometric morphometrics for the identification of two ommastrephid squid species from the Mexican Pacific coast. Measurements of statoliths from squids belonging to the family Loliginidae were also included to increase certainty. Species were identified with a 100% correct assignment; hence, statolith shape confirmed the taxonomic value of this structure. A description of statolith morphology for each target species is provided for further use in species identification when other morphological characteristics of the squids are not available.

 

[octobot]

Dorset Echo​

Octopus discovered on Weymouth beach
Dorset Echo
A nature lover made an unusual find as he came across an octopus washed up on Weymouth Beach during his morning walk. Bob Ford, who runs guided walks around Weymouth and Portland, discovered the sea creature during a walk on the beach on Wednesday ...


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