gjbarord;197376 said:One reason could be that cuttlefish spend a greater percentage of their lives in more of a horizontal position than other cephs...
Greg
Mechanisms of Population Structuring in Giant Australian Cuttlefish Sepia apama[/URL]
NL Payne, EP Snelling, JM Semmens, BM Gillanders - PLOS ONE, 2013
... Large-scale movement has been observed in all stages of cephalopod life history [11], from
passive drifting of paralarvae to migrations over several thousands of kilometres in adults [12]. ...
(2007) Approaches to resolving cephalopod movement and migration patterns. ...
[URL="http://scholar.google.com/scholar_url?hl=en&q=http://www.biolbull.org/content/224/1/47.short&sa=X&scisig=AAGBfm3Br2bc-jTwXrEPSKsaFu6dCp0hpw&oi=scholaralrt"]Microtransplantation of Cellular Membranes From Squid Stellate Ganglion Reveals Ionotropic GABA Receptors[/URL]
L Conti, A Limon, E Palma, R Miledi - The Biological Bulletin, 2013
... E-mail: luca.c83{at}libero.it; alimonru{at}uci.edu. Next Section. Abstract. The squid has been the
most studied cephalopod, and it has served as a very useful model for investigating the events
associated with nerve impulse generation and synaptic transmission. ...
[URL="http://scholar.google.com/scholar_url?hl=en&q=http://www.sciencedirect.com/science/article/pii/S0022098113000609&sa=X&scisig=AAGBfm35Q5tpXOrKpwQyvwQZFEcODxcM9g&oi=scholaralrt"]The effects of prospective anaesthetic substances on cephalopods: Summary of original data and a brief [/URL]review of studies over the last two decades
IG Gleadall - Journal of Experimental Marine Biology and Ecology, 2013
Trials were performed with magnesium chloride, ethanol and eight more complex organic
substances screened for their effect as immersion anaesthetics for small,.
[URL="http://scholar.google.com/scholar_url?hl=en&q=http://journals.cambridge.org/abstract_S0022112013000657&sa=X&scisig=AAGBfm3Cz2XkbG_DTlAsA1eZq61vbPx5zw&oi=scholaralrt"]Ultra-fast escape of a deformable jet-propelled body[/URL]
GD Weymouth, MS Triantafyllou - Journal of Fluid Mechanics, 2013
... In this work a cephalopod-like deformable body that fills an internal cavity with fluid and expels
it to propel an escape manoeuvre, while undergoing a drastic external shape change through
shrinking, is shown to employ viscous as well as mainly inviscid hydrodynamic ...
[URL="http://scholar.google.com/scholar_url?hl=en&q=http://www.sciencedirect.com/science/article/pii/S0022098113000774&sa=X&scisig=AAGBfm2yjqnjx3c-uF4nIum7r7SPY9aoYA&oi=scholaralrt"]Measurements of octopus arm elongation: Evidence of differences by body size and gender[/URL]
B Mazzolai, L Margheri, P Dario, C Laschi - Journal of Experimental Marine Biology …, 2013
This study describes a new method for the measurement of Octopus vulgaris arm elongation
ability and presents the first preliminary data on sex- and size-relate.
[URL="http://scholar.google.com/scholar_url?hl=en&q=http://www.sciencedirect.com/science/article/pii/S0042698913000564&sa=X&scisig=AAGBfm1NIf4DhFMT2Zj68p3dEd819tC-Iw&oi=scholaralrt"]How visual edge features influence cuttlefish camouflage patterning[/URL]
CC Chiao, KM Ulmer, LA Siemann, KC Buresch… - Vision Research, 2013
... ways. Keywords. Edge perception; Spatial frequency; Line terminator; Disruptive
body pattern; Sepia officinalis. 1. Introduction. Cephalopod camouflage is the fastest
changing and most versatile in the animal kingdom. These ...
A method for long-term electronic tagging and tracking of juvenile and adult European common cuttlefish Sepia officinalisAbstract
Cephalopod culture is expected to increase in the near future and sperm cryopreservation would be a valuable tool to guarantee sperm availability throughout the year and to improve artificial insemination programs. We have studied the tolerance of spermatophores from the oceanic squid Illex coindetii to several cryoprotectants, in two toxicity experiments and a cryopreservation test. Five permeating cryoprotectants were tested: Dimethyl sulfoxide (Me2SO), methanol, glycerol, propylene glycol and ethylene glycol. In the first experiment, spermatophores were exposed to the five cryoprotectants at 5% (v/v) and 15% (v/v) at 4 °C for 5 min. In the second experiment, spermatophores were exposed to the cryoprotectants at 15% using different exposure times: 5, 15 and 30 min. In a third experiment, we tested two cryopreservation protocols: LN2 vapor or −80 °C freezer, using a 15% cryoprotectant and 15 or 30 min of exposure. Viability and mitochondrial activity were assessed using Mitotracker deep red, YOPRO1 and Hoechst 33342, by flow cytometry. Spermatozoa in this species remain viable after cryoprotectant exposure but their quality decreased considerably after cryopreservation, only 5–10% of spermatozoa being motile. Flow cytometry demonstrated that Me2SO may be the most appropriate cryoprotectant for I. coindetii spermatozoa, and shows a first approach on cephalopod sperm cryopreservation, opening new possibilities for the research and culture of this group of molluscs.
May be most interesting because of this oddity:Partial Abstract:
Cephalopod culture is expected to increase in the near future and sperm
cryopreservation would be a valuable tool to guarantee sperm availability throughout the
year and to improve artificial insemination programs.
The publisher regrets that this article has been temporarily removed. A replacement will appear as soon as possible in which the reason for the removal of the article will be specified, or the article will be reinstated.
Abstract
Dosidicus gigas (jumbo or Humboldt squid) is a semelparous, major predator of the eastern Pacific that is ecologically and commercially important. In the Gulf of California, these animals mature at large size (>55 cm mantle length) in 1-1.5 years and have supported a major commercial fishery in the Guaymas Basin during the last 20 years. An El Niño event in 2009-2010 was accompanied by a collapse of this fishery, and squid in the region showed major changes in distribution and life history strategy. Large squid abandoned seasonal coastal-shelf habitats in 2010 and instead were found in the Salsipuedes Basin to the north, an area buffered from the effects of El Niño by tidal upwelling and a well-mixed water column. The commercial fishery also relocated to this region. Although large squid were not found in the Guaymas Basin from 2010-2012, small squid were abundant and matured at an unusually small mantle-length (
Abstract
Cuttlebone is a natural marine cellular material possessing the exceptional mechanical properties of high compressive strength, high porosity and high permeability. This combination of properties is exceedingly desirable in biomedical applications, such as bone tissue scaffolds. In light of recent studies, which converted raw cuttlebone into hydroxyapatite tissue scaffolds, the impact of morphological variations in the microstructure of this natural cellular material on the effective mechanical properties is explored in this paper. Two extensions of the finite element-based homogenization method are employed to account for deviations from the assumption of periodicity. Firstly, a representative volume element (RVE) of cuttlebone is systematically varied to reflect the large range of microstructural configurations possibly among different cuttlefish species. The homogenization results reveal the critical importance of pillar formation and aspect ratio (height/width of RVE) on the effective bulk and shear moduli of cuttlebone. Secondly, multi-cell analysis domains (or multiple RVE domains) permit the introduction of random variations across neighboring cells. Such random variations decrease the bulk modulus whilst displaying minimal impact on the shear modulus. Increasing the average size of random variations increases the effect on bulk modulus. Also, the results converge rapidly as the size of the analysis domain is increased, meaning a relatively small multi-cell domain can provide a reasonable approximation of the effective properties for a given set of random variation parameters. These results have important implications for the proposed use of raw cuttlebone as an engineering material. They also highlight some potential for biomimetic design capabilities for materials inspired by the cuttlebone microstructure, which may be applicable in biomedical applications such as bone tissue scaffolds.
Cephalopods are renowned for their ability to adaptively camouflage on diverse backgrounds. Sepia officinalis camouflage body patterns have been characterized spectrally in the laboratory but not in the field due to the challenges of dynamic natural light fields and the difficulty of using spectrophotometric instruments underwater. To assess cuttlefish color match in their natural habitats, we studied the spectral properties of S. officinalis and their backgrounds on the Aegean coast of Turkey using point-by-point in situ spectrometry. Fifteen spectrometry datasets were collected from seven cuttlefish; radiance spectra from animal body components and surrounding substrates were measured at depths shallower than 5 m. We quantified luminance and color contrast of cuttlefish components and background substrates in the eyes of hypothetical di- and trichromatic fish predators. Additionally, we converted radiance spectra to sRGB color space to simulate their in situ appearance to a human observer. Within the range of natural colors at our study site, cuttlefish closely matched the substrate spectra in a variety of body patterns. Theoretical calculations showed that this effect might be more pronounced at greater depths. We also showed that a non-biological method ("Spectral Angle Mapper"), commonly used for spectral shape similarity assessment in the field of remote sensing, shows moderate correlation to biological measures of color contrast. This performance is comparable to that of a traditional measure of spectral shape similarity, hue and chroma. This study is among the first to quantify color matching of camouflaged cuttlefish in the wild.
PMID: 23254307 [PubMed - in process]
Abstract
Cephalopod skin is soft, flexible, and produces rapid color changes for camouflage and signaling primarily by regulating the shapes of its numerous chromatophore organs. Each chromatophore has 10–30 radial muscle cells, termed fibers, under central nervous system control. Each fiber contains myofilaments that contract in concert to stretch the pigment-containing cell from its punctate, spherical state to a fully expanded thin disk of color. Expansion occurs in less than one second and can result in a 14-fold expansion in pigment cell diameter. We investigated the anchoring mechanism of radial muscle fibers that expand pigment cells in the longfin squid, Doryteuthis (Loligo) pealeii. The proximal Active Zone of a radial muscle fiber adheres to the pigment cell within an ensheathing sinus. The distal portion forms terminal arbors, thereby increasing the surface area, to adhere it to the dermal extracellular matrix (ECM). While the muscle fiber is attached to the pigment cell with haptosomes, the remainder of the fiber is adhered to the surrounding basal lamina (part of the ECM) by numerous, closely spaced, small costamere-like projections. Branching of the radial muscle fiber termini and the costamere-like attachments are key anatomical specializations that anchor the radial muscle fibers in the pliable skin while allowing the freedom of movement required for large changes in pigment cell diameter. We postulate that these features may be relevant for the development of soft actuation models in materials science.
Abstract
Difficulties in elucidating the evolutionary history of the octopods have arisen from problems in identifying informative morphological characters. Recent classifications have divided the largest group, the incirrate octopods, into five groups. These include the pelagic superfamily Argonautoidea and three gelatinous pelagic families (Vitreledonellidae, Bolitaenidae, Amphitretidae). All benthic incirrate octopods have been accommodated in the family Octopodidae, itself divided into four subfamilies, Octopodinae, Eledoninae, Bathypolypodinae and Graneledoninae, which are defined by the presence or absence of an ink sac, and uniserial or biserial sucker arrangements on the arms. We used relaxed clock models in a Bayesian framework and maximum likelihood methods to analyse three nuclear and four mitochondrial genes of representatives from each of the previous subfamilies. Strong evidence indicates that the family Octopodidae is paraphyletic and contains the gelatinous pelagic families. The subfamilies of Octopodidae recognised in earlier works do not reflect evolutionary history. The following clades were supported in all analyses: (1) Eledone/Aphrodoctopus, (2) Callistoctopus/Grimpella/Macroctopus/Scaeurgus, (3) Abdopus/Ameloctopus/Amphioctopus/Cistopus/Hapalochlaena/Octopus, (4) Enteroctopus/Muusoctopus/Vulcanoctopus, (5) Vitreledonella/Japetella, (6) Southern Ocean endemic and deep-sea taxa with uniserial suckers. These clades form the basis for a suite of taxa assigned family taxonomic rank: Amphitretidae, Bathypolypodidae, Eledonidae, Enteroctopodidae, Megaleledonidae and Octopodidae sensu nov. They are placed within the superfamily Octopodoidea