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The present study identifies one species of the genus Octopus in the order: Octopoda (Cephalopoda: Mollusca), recorded forthe first time in the Iraqi coastal waters and Arabian-Persian Gulf. The study extended from January 2019 to December of thesame year. The Octopus specimens were seasonally obtained from the fishing trawlers operating in the Iraqi coastal waters inthe South of Al- Fao District, Basrah- Iraq, NW Arabian Gulf. The Octopus was identified as O. vulgaris in Iraqi coastal watersdepending on morphological features. The habitats of living specimens are briefly described. Some observations were reported on the occurrence of this species and the measurement of some environmental factors. The species was identified up to spe-cies level using standard literature. This species looks similar morphologically to the species which is already identified from the other areas around the world. The present study records significant expansion in the distribution range of this species.

Chemical evaluation of specialised metabolites from the old-lady marine octopus Cistopus indicus (family Octopodidae) led to the isolation of an undescribed 14-membered bislactonic macrodio-lide cistobislactone, which was characterized as 12-(4’-ethyl-6’- methoxy-3’-methyl-hex-1-enyl)-5,11-dihydroxy-6-methyl-1,7-dioxa-cyclotetradeca-3,9-diene-2,8-dione. Cistobislactone exhibited noticeably greater inhibitory potential against 5-lipoxygenase (IC50 2.06 mM) compared to standard anti-inflammatory agent ibupro-fen (IC50 4.61 mM, p < 0.05). Superior antioxidant properties of cis-tobislactone against the oxidants (IC50 -1.8 mM) also reinforced its promising anti-inflammatory activity. Higher electronic proper-ties (topological polar surface area of 102.3) and balanced hydro-phobicity (logarithm of octanol-water coefficient -3) could recognize its higher interaction at the enzyme active site resulting in an effective attenuation of 5-lipoxygenase and efficient inter-membrane permeability. Comparatively lesser binding energy (-6.5 kcal mol-1 ) and docking score (-7.5 kcal mol-1 ) of cistobislac-tone with the aminoacyl residues of 5-lipoxygenase could further recognize its anti-inflammatory potential.

As per the FAO data, octopus identification is very limited in the species level at world fishery and also they are cryptic nature. On the other hand, Indonesia is one of the top ten highest octopus exporters. This study therefore aimed to determine the species of octopus based on phylogenetic analysis of mt-DNA COI. Octopuses were collected from nine different locations throughout Indonesia, i.e., Anambas, Bangka-Belitung, Cirebon, Karimunjawa, Tuban, Lombok, Buton, Wakatobi and Jayapura. Samples were mostly in the form of tentacles that were directly collected from fishermen. After being preserved in 96% ethanol, the sample was extracted in 10% chelexÒ, PCR amplification using Folmer’s primer then was further analysed by sequencing in Sanger methods. Of the 24 samples sequenced, the results recognized four species Octopodidae belongs to the three genera, named Amphioctopus aegina, Hapalochlaena fasciata, Octopus laqueus and Octopus cyanea. Mean pair-wise distances of within-species were ranged from 0 to 5.5 % and between-species was ranged from 12.9 to 15.8 %. This study distinctly confirmed the difference between genus Amphioctopus and Hapalochlaena (15.5 %), as also between O. laqueus and O. cyanea (12.9%) which was previously not completely distinguished. Although performing species identification using DNA sequences for shallow-water benthic octopus species is perhaps considered premature, this study indicated the possible application of COI sequences for species identification, thereby providing a preliminary dataset for future DNA barcoding of octopus, in particular for Indonesia waters.

Deep-sea sampling was conducted by a commercial trawl in the International Waters of Mersin Bay between 14 and 17 May 2018. The sampling depth ranged between 274 and 641 meters. A total of 13 trawling operations were performed, and each trawling operation lasted approximately 4 hours. During the sampling, six of the deep-sea cephalopods species were caught. All specimens were preserved in ethyl alcohol and were deposited in the Museum of the Systematic, Faculty of Fisheries, Mersin University (Catalog no: MEUCC-18-11-2- MEUCC-18-11-7). A total of two cuttlefish species belonging to the families of Sepiidae were identified. The others were represented by the families of Sepiolidae, Octopodidae, Bathypolypodidae, and Ommastrephidae.

Octopus cyanea is a species of particular economic importance for coastal regions in the tropical Indo-Pacific, including the Mauritian island of Rodrigues. At present, little is known about their ...

This study presented 96 cox1 and 76 cox3 genes of Amphioctopus neglectus populations. Three distinct lineages were formed from phylogenetic trees and networks constructed using haplotypes. Mitogenomes of A. neglectus-a and A. neglectus-b as the representatives of two lineages separated from population genetics were sequenced to compare with A. neglectus at the genome-level. Amphioctopus neglectus-a showed significant differences with A. neglectus, mainly reflected in gene length, intergenic regions and the secondary structure of tandem repeat motifs. Notably, two sequence deletions in mitogenomes of the two representative species were detected in different positions of major non-coding regions, which were the most distinct differences with A. neglectus. Pairwise genetic distances and the phylogenetic analysis supported the relationship of (A. neglectus-a + (A. neglectus + A. neglectus-b)). This study suggested that A. neglectus-a should be considered as a potential cryptic species of this complex, while A. neglectus-b needed further verification to be defined.

Southeast Pacific (SEP) oceanic islands are characterized by their extreme isolation and high degree of endemism. To date, most research has focused on species composition and distributions, with little information available on early life stages. In this study, we provide new records of early life stages of cephalopods based on planktonic collections carried out during October and November 2016 around three oceanic islands: San Félix, San Ambrosio (Desventuradas Islands; 26.3°S, 79.8°W), and Alejandro Selkirk (Juan Fernández Archipelago; 33.7°S, 80.7°W), which are part of the Nazca-Desventuradas Marine Park, the largest marine park in the Americas. Twenty-four paralarvae and juveniles were obtained and identified based on morphological characteristics [i.e., mantle length (ML), chromatophore patterns, number and shape of suckers on arms and tentacles] and DNA barcoding [i.e., mitochondrial Cytochrome c Oxidase subunit I (COI) sequences]. Six families were recorded, including Brachioteuthidae, Onychoteuthidae, Tremoctopodidae, Octopodidae, Octopoteuthidae, and Lycoteuthidae. Most individuals (92%) corresponded to larger stages of 4–12 mm ML (Brachioteuthidae, Onychoteuthidae, Tremoctopodidae, and Lycoteuthidae), and 8% were newly hatched paralarvae of around 1 mm ML (Octopodidae and Octopoteuthidae). The DNA barcoding approach validated the identity of Brachioteuthis sp., Onykia aff. robsoni , Octopus mimus, and Tremoctopus sp., with two specific identities (Octopoteuthidae and Lycoteuthis sp.) remaining to be evaluated. ese records provide new information on cephalopod diversity and distribution around SEP islands, adding to the current knowledge about zoogeographic patterns of this group and evidencing their potential relationships with continental or nearby habitats.

We report an interaction between Octopus insularis (Octopoda, Octopodidae) and the reef fish Alphestes afer (Perciformes, Epinephelidae) and provide evidence of mimicry, camouflage and following behaviors. We observed three instances of this interaction during dives at the Pirangi reefs, Northeastern Brazil. The octopus’s body color patterns indicated the type of behavior that developed while it was followed by the reef fish. These data are the first records of following behavior in A. afer and the first observation of such interaction with O. insularis in coastal reefs.

In this study, we described a new species of octopus and named it Callistoctopus xiaohongxusp. nov. based on nine specimens captured in the waters of southeast China. Callistoctopus xiaohongxusp. nov. is a small to moderate-sized octopus. The most characteristic and defining morphological features are the reddish-orange to reddish-brown skin, gills with 8 or 9 lamellae per demibranch, \∧/-shaped funnel organ, and small suckers. Fragments obtained from the mitochondrial cytochrome c oxidase subunit I (COI) gene of nine specimens were 593 bp in length, and the genetic distance among the specimens of C. xiaohongxusp. nov. and the other 16 octopods ranged from 11.13 to 21.09%. Topologies resulting from ML and BI analyses of the COI gene showed a highly supported monophyletic clade (bootstrap value [BS] = 94%, posterior probability [PP] = 100%) containing all the specimens identified as C. xiaohongxusp. nov.

The complete mitochondrial genome of the East Asian common octopus (Octopus sinensis) was determined and analyzed in this work. The circular mitogenome of O. sinensis is 15,737 bp in length with 21.53% GC content, which contains two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), 13 protein-coding genes (PCGs) and a non-coding region (D-loop). The analysis of the SNPs revealed 4 conservative SNPs for COI gene of O. sinensis compared with Octopus vulgaris. Phylogenetic analysis suggested that O. sinensis is closely related to O. vulgaris. This sequence data would play an important role in the investigation of phylogenetic relationship and taxonomy of the class Cephalopoda.

Octopus djinda Amor, sp. nov. (Figs. 2���3) Octopus tetricus, Joll et al. 1976, 1977, 1978; Roper et al. 1984: 209; Kirkman et al. 1991: 557; Stranks 1998: 541 (in part); Guerra et al. 2010: 1405 (in part); Acosta-Jofre et al. 2012 (in part); Reid & Wilson 2015 (in part); Greenwell et al. 2019. Octopus cf. tetricus, Roper 1997; Norman & Reid 2000; Finn et al. (2005); Guzik et al. 2005; Norman & Hochberg 2005: 146; Amor et al. 2014; Norman et al. 2014: 58; Leporati & Hart 2015; Leporati et al. 2015; Hart et al. 2016; Reid 2016: 396; Amor et al. 2017; Sauer et al. 2020; Somaweera & Somaweera 2021. Octopus aff. tetricus, Hart et al. 2019. Type material. Seven type specimens were designated, including at least one male and one female from each sampled locality which encompasses most of the species��� distribution. Other material examined (a further 7 males and 11 females) are listed in Table 1 (n = 25). Raw morphological data are available in Tables S1���S 4. Holotype: AUSTRALIA: Western Australia: Esperance: Male, 138.6 mm ML (Fig. 3). Collected by M. Amor 10-Dec-2019 via non-baited trap, 7���9 m depth. Esperance Bay (-33.84, 121.91) (WAM S.89010). Paratypes: AUSTRALIA: Esperance: (i) Female, 163.4 mm ML. Collected by M. Amor 10-Dec-2019 via non-baited trap, 7���9 m depth. Esperance Bay (-33.84, 121.91) (WAM S.89009); Mandurah: (ii) Male, 163.4 mm ML. Collected by M. Amor 12-Dec-2019 via baited trap, 22���25 m depth (-32.77, 115.53) (WAM S.89021); (iii) Male, 177.0 ML. Collected by M. Amor 12-Dec-2019 via baited trap, 22���25 m depth (-32.75, 115.51) (WAM S.89022); (iv) Female, 124.3 mm ML. Collected by M. Amor 12-Dec-2019 via baited trap, 22���25 m depth (-32.78, 115.52) (WAM S.89018); Geraldton: (v) Male, 176.1 mm ML. Collected by M. Amor 2-Dec-2019 via baited trap, 16���30 m depth (-28.83, 114.55) (WAM S.89001); (vi) Female, 149.7 mm ML. Collected by M. Amor 2-Dec-2019 via baited trap, 16���30 m depth (-28.92, 114.57) (WAM S.89006). Diagnosis. Medium to large (109���177 mm ML), muscular species. Ocelli absent. Long arms taper to narrow tips between 347���745 mm; 3.7���6 times longer than ML. All arms equal width (12.5-32.1 mm). Males right arm III hectocoltylised; shorter than opposite arm (ALR3 84���97% ALL3). Well-defined spermatophore groove ends at base of small calamus. Calamus approximates 31���49% of ligula. Small ligula (LL 1���1.6% ALR3). Biserial sucker arrangement; 182���283 suckers on non-hectocotylised arms, 169���196 hectocotlised arm suckers. Between 1���13 enlarged suckers present in both sexes; between 10 th to 23 rd proximal suckers on II and III arm pairs. Description. Based on 11 mature males and 14 sub-mature females. Mantle broad, oval shaped and saccular. Web depth 18���31% of longest arm, formula highly variable. Funnel tube shaped; free length 45���85% of total funnel length (39���66 mm). Funnel organ ���W��� shaped. 9���10 lamellae per gill demibranch. Ink sac, anal flaps present. One large papilla above each eye, 2���3 additional smaller papillae adjacent. Typical Octopus digestive tract (Fig. 4) comprising a large buccal mass connected to a pair of rounded anterior salivary glands. Posterior salivary glands curved and triangular. Narrow oesophagus leads to crop diverticulum then wide, triangular, stomach. Spiral caecum connected to large digestive glad; ink sac embedded within. Long intestine ending with muscular rectum, pair of anal flaps. Strong beak embedded within buccal mass (Fig. 5A & 5B). Radula comprises rows of seven teeth, two marginal plates. Rhachidian tooth, 2���3 cusps migrating laterally, and asymmetrically over four rows. Pattern offset by two rows (WAM S89017; Fig. 5C). Spawned eggs 2.5 mm long, 1 mm wide. Larvae planktonic. Mature male testis, large (Fig. 6A), narrow vas deferens opens into a round mucilage gland, then long, curved spermatophore gland (Fig 6B & 6C). Spermatophore sac connected, 32���111 spermatophores within. Spermatophores long (to 50 mm), and narrow (0.6���0.7 mm). Terminal organ 13���24% of ML. Diverticulum elongate, oval-shaped (5���14 mm). Ovaries to 28 g (sub-mature). Short proximal oviducts, lead to spherical oviductal glands and distal oviducts (Fig. 6D). Rough skin texture, distinct patches. Live specimens display mottled colour pattern, vary in colour from oceanic (reddish-brown/orange) to estuarine habitats (green/brown tint). Characteristic orange colouration along arm edge; often displayed while denned. Colour muted by preservation. Distribution. Shark Bay (northernmost distribution; approx. -25.51, 112.87) to Cape Le Grand (southeast; approx. -33.94, 122.55), Western Australia (Fig. 1). Depth to 80 m. Mean sea surface temperatures from ~25���17 (Fig. S1; Huang et al. 2017). Etymology. Octopus djinda, sp. nov, the star octopus, is distributed along the southwest coast of Australia. This distribution closely reflects the territory of the traditional custodians of this land, the Nyoongar people (���a person of the southwest of Western Australia���). To recognise their connection to this land, a Nyoongar translation of ���star��� (djinda), as described by Whitehurst (1997), was selected as a species name. This use of ���star��� (luminous) reflects the shared recent ancestry with, and now-understood distinction from, O. tetricus (Latin: gloomy octopus). Consultation with the Aboriginal community regarding the use of ���djinda��� as a species name was undertaken via the Western Australian Museum���s Aboriginal Advisory Committee (WAMAAC). Initial documentation, including the above etymology statement, was presented to the committee on Friday July 2, 2021. Support was provided on July 14, 2021. Remarks. Greater, and non-overlapping, sucker numbers on hectocotylised arm delimit O. djinda, sp. nov. (169���196) from O. tetricus (122���150; Amor et al. 2017) and O. sinensis d���Orbigny, 1841 from Asia (119���152; Gleadall 2016), but not Kermadec Is. (178���185; Reid & Wilson, 2015). Disjunct distributions reflect species identity among O. djinda, O. tetricus and O. sinensis, which form a monophyletic clade within the O. vulgaris group (Amor et al. 2019). A 399 bp fragment of the COI gene was sequenced to complement visual identification. Sequence data from 16 individuals, that were of sufficient quality, were retained and represented a single haplotype. 349 bases overlapped with existing accessions for O. tetricus and O. cf. tetricus. 13 polymorphisms along 349 bp partial COI sequence (3.7% divergence) reliably distinguish O. djinda, sp. nov. from O. tetricus; interspecific variation nine times greater than intraspecific differences. Four characteristic large papillae form a diamond pattern on the dorsal mantle, typical for the O. vulgaris species-group. Funnel organ was difficult to see in most specimens., Published as part of Amor, Michael D. & Hart, Anthony M., 2021, Octopus djinda (Cephalopoda: Octopodidae): a new member of the Octopus vulgaris group from southwest Australia, pp. 145-156 in Zootaxa 5061 (1) on pages 148-151, DOI: 10.11646/zootaxa.5061.1.7, http://zenodo.org/record/5642369, {"references":["Joll, L. M. (1976) Mating, egg-laying and hatching of Octopus tetricus (Mollusca: Cephalopoda) in the laboratory. Marine Biology, 36 (4), 327 - 333. https: // doi. org / 10.1007 / BF 00389194","Joll, L. M. (1977) Growth and food intake of Octopus tetricus (Mollusca: Cephalopoda) in aquaria. Marine and Freshwater Research, 28 (1), 45 - 56. https: // doi. org / 10.1071 / MF 9770045","Joll, L. M. (1978) Observations on the embryonic development of Octopus tetricus (Mollusca: Cephalopoda). Marine and freshwater research, 29 (1), 19 - 30. https: // doi. org / 10.1071 / MF 9780019","Kirkman, H., Humphries, P. & Manning, R. 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(2000) Guide to squid, cuttlefish and octopuses of Australasia. CSIRO Publishing, Melbourne, 96 pp. https: // doi. org / 10.1071 / 9780643101098","Finn, J. K., Hochberg, F. G. & Norman, M. D. (2005) Phylum Dicyemida in Australian waters: First record and distribution across diverse cephalopod hosts. Phuket Marine Biology Research Center Bulletin, 66 (8), 96.","Guzik, M. T., Norman, M. D. & Crozier, R. H. (2005) Molecular phylogeny of the benthic shallow-water octopuses (Cephalopoda: Octopodinae). Molecular Phylogenetics and Evolution, 37 (1), 235 - 248. https: // doi. org / 10.1016 / j. ympev. 2005.05.009","Norman, M. D. & Hochberg, F. G. (2005) The current state of octopus taxonomy. Phuket Marine Biological Center Research Bulletin, 66, 127 - 154.","Amor, M. D., Norman, M. D., Cameron, H. E. & Strugnell, J. M. (2014) Allopatric speciation within a cryptic species complex of Australasian octopuses. Plos One, 9 (6), e 98982 .. https: // doi. org / 10.1371 / journal. pone. 0098982","Hart, A. M., Leporati, S. C., Marriott, R. J. & Murphy, D. (2016) Innovative Development of the Octopus (cf) tetricus fishery in Western Australia. FRDC Project No 2010 / 200. Fisheries Research Report. No. 270. Department of Fisheries, Western Australia, 120 pp.","Reid, A. (2016) Cephalopods of Australia and sub-Antarctic territories. CSIRO Publishing, Melbourne, 446 pp. https: // doi. org / 10.1071 / 9781486303946","Amor, M. D., Norman, M. D., Roura, A., Leite, T. S., Gleadall, I. G., Reid, A., Perales-Raya, C., Lu, C. C., Silvey, C. J., Vidal, E. A. G., Hochberg, F. G., Zheng, X. D. & Strugnell, J. M. (2017) Morphological assessment of the Octopus vulgaris species complex evaluated in light of molecular-based phylogenetic inferences. Zoologica Scripta, 46 (3), 275 - 288. https: // doi. org / 10.1111 / zsc. 12207","Sauer, W. H., Gleadall, I. G., Downey-Breedt, N., Doubleday, Z., Gillespie, G., Haimovici, M., Ibanez, C. M., Katugin, O. N., Leporati, S., Lipinski, M. R., Markaida, U., Ramos, J. E., Rosa, R., Villanueva, R., Arguelles, J., Briceno, F. A., Carrasco, S. A., Che, L. J., Chen, C. S., Cisneros, R., Conners, E., Crespi-Abril, A. C., Kulik, V. V., Drobyazin, E. N., Emery, T., Fernandez-Alvarez, F. A., Furuya, H., Gonzalez, L. W., Gough, C., Krishnan, P., Kumar, B., Leite, T., Lu, C. C., Mohamed, K. S., Nabhitabhata, J., Noro, K., Petchkamnerd, J., Putra, D., Rocliffe, S., Sajikumar, K. K., Sakaguchi, H., Samuel, D., Sasikumar, G., Wada, T., Zheng, X., Tian, Y., Pang, Y., Yamrungrueng, A. & Pecl, G. (2020) World octopus fisheries. Reviews in Fisheries Science & Aquaculture, 29 (3), 279 - 429. https: // doi. org / 10.1080 / 23308249.2019.1680603","Somaweera, R. & Somaweera, R. (2021) Nuclear-follower foraging behaviour between Western Australian common octopus and brown-spotted wrasse. Marine and Freshwater Research. https: // doi. org / 10.1071 / MF 21059","Hart, A. M., Murphy, D., Hesp, S. A. & Leporati, S. (2019) Biomass estimates and harvest strategies for the Western Australian Octopus aff. tetricus fishery. ICES Journal of Marine Science, 76 (7), 2205 - 2217. https: // doi. org / 10.1093 / icesjms / fsz 146","Huang, B., Thorne, P. W., Banzon, V. F., Boyer, T., Chepurin, G., Lawrimore, J. H., Menne, M. J., Smith, T. M., Vose, R. S. & Zhang, H. (2017) NOAA Extended Reconstructed Sea Surface Temperature (ERSST), Version 5. NOAA National Centers for Environmental Information Available from: https: // psl. noaa. gov / data / gridded / data. noaa. ersst. v 5. html (accessed 10 August 2021) https: // doi. org / 10.7289 / V 5 T 72 FNM","Whitehurst, R. (1997) Noongar Dictionary. 2 nd Edition. Noongar Language and Cultural Centre, Perth, 53 pp. Available from: https: // www. noongarculture. org. au / noongar-dictionary-by-rose-whitehurst (accessed 1 November 2019)","Gleadall, I. G. (2016) Octopus sinensis d'Orbigny, 1841 (Cephalopoda: Octopodidae): valid species name for the commercially valuable East Asian common octopus. Species Diversity, 21 (1), 31 - 42. https: // doi. org / 10.12782 / sd. 21.1.031","Amor, M. D., Doyle, S. R., Norman, M. D., Roura, A., Hall, N. E., Robinson, A. J., Leite, T. S. & Strugnell, J. M. (2019) Genomewide sequencing uncovers cryptic diversity and mito-nuclear discordance in the Octopus vulgaris species complex. BioRxiv preprint. [published online] https: // doi. org / 10.1101 / 573493"]}

O'Brien, Caitlin E., Bennice, Chelsea O., Leite, Tatiana (2021): A field guide to distinguishing Octopus insularis and Octopus americanus (Octopoda: Octopodidae). Zootaxa 5060 (4): 589-594, DOI: https://doi.org/10.11646/zootaxa.5060.4.8

Biochemical analysis of secondary metabolites of marine old-woman octopus Cistopus indicus (family Octopodidae) led to the identification of two sixteen-membered spiro-linked macrocyclic bislactones, named as cistobislactone A and cistobislactone B with unprecedented feature of henicos framework, based on extensive spectroscopic analyses. Cistobislactone B exhibited potential inhibition property against arachidonate 5-lipoxygenase (IC50 2.18 mM) than that demonstrated by cistobislactone A (IC50 2.54 mM) and standard non-steroidal anti-inflammatory agent ibuprofen (IC50 4.50 mM) thus signifying the higher anti-inflammatory activity of the cistobislactone B analogue. The studied macrocyclic bislactones exhibited promising antioxidant potential, in which cistobislactone B exhibited potential radical quenching (IC50 2.33 mM) and hydrogen peroxide scavenging (IC50 1.81 mM) activities that were proximal to the commercial anti-oxidant α-tocopherol (IC50 ~ 1.60 mM). This further reinforced its attenuation property against arachidonate 5-lipoxygenase. Considerably greater electronic properties coupled with balanced hydrophobicity of cistobislactone B could ascribe the superior ligand-receptor interfaces leading to its anti-inflammatory activity. Molecular docking analysis of cistobislactone B with 5-lipoxygenase recorded lesser docking score (−12.24 kcal mol−1) and binding energy (−11.24 kcal mol−1), which further supported its anti-inflammatory activity. Cistobislactone B, with six fold lesser value of inhibition constant (Ki 5.76 nM) towards 5-lipoxygenase than that displayed by cistobislactone A, could describe the superior protein-ligand interactions of the former. The undescribed cistobislactone B might be a potential natural anti-inflammatory lead to moderate the odds of inflammatory pathologies.

The diet of the Hubb's octopus Octopus hubbsorum along the coast of Acapulco, Guerrero, Mexico, was determined by analysing the stomach contents of 413 individuals collected monthly between February 2017 and March 2018. Most stomachs (74.3%) presented contents, while 25.7% were empty. Sixty prey items were identified and grouped into 16 categories. The most frequent prey items were Petrolisthes sanfelipensis, Clastotoechus diffractus, Petrolisthes hians and Alpheus spp. Smith's index indicated that O. hubbsorum follows a generalist diet for each hydroclimatic season, sex and size class (1: juvenile; 2: young adult; 3: mature adult). Cannibalism was frequent among males, less so among females. Pianka's index revealed a higher overlap among the three size classes of both sexes during the dry season, while during the rainy season the overlap was reduced for size classes 2 and 3 in both sexes. The average isotopic values overall were δ13C −14.96‰ (±0.08) and δ15N 13.02‰ (±0.09). A significant difference (P = 0.005) was observed in δ13C among hydroclimatic seasons (rainy and dry) and size classes, while for δ15N a significant difference (P = 0.013) was observed between seasons. Stomach content analysis gave values of the trophic position of O. hubbsorum ranging from 3.57 to 3.72, whereas the values obtained using stable isotope analysis, using δ15N, ranged from 3.52 to 3.86. Variation was observed in isotopic niche size and Layman's metrics among hydroclimatic seasons. A higher isotopic niche overlap was observed between size classes 2 and 3 during the dry season. The rocky shore ecosystem has been heavily exploited by artisanal fisheries (fish and invertebrates). A more integrated, ecosystem-based management of these fisheries requires an understanding of their trophic structure.

The new species, Paroctopus cthulu sp. nov. Leite, Lima, Lima and Haimovici was recorded from shallow coastal waters of south and southeastern Brazil, where most specimens were found sheltered in marine debris. It is a small octopus; adults are less than 35 mm mantle length (ML) and weight around 15 g. It has short- to medium-sized arms, enlarged suckers on the arms of both males and females, a relatively large beak (9% ML) and medium to large mature eggs (3.5 to > 9 mm). The characteristics of hatchlings of two brooding females, some of their anatomical features, and in situ observations of their behavior are a clue to the life history of it and closely related pygmy octopuses. The Bayesian phylogenetic analysis showed that Paroctopus cthulu sp. nov. is grouped in a well-supported clade of Paroctopus Naef, 1923 species, clearly distinct from Octopus joubini Robson, 1929 and Paroctopus mercatoris (Adam, 1937) from the Northwestern Atlantic. The description of this new species, living in habitat altered by humans, debris in shallow water off Brazil, offered an opportunity not only to evaluate the relationship among the small octopuses of the western Atlantic, Caribbean and eastern Pacific, but also their adaptation to the Anthropocene period.

The diversity patterns of cephalopod early-life stages on the continental shelf of Southeastern Brazilian Bight (SBB, 22–25°S) were investigated using a historical plankton archive of 22 oceanographic cruises carried out from 1974 to 2010. From 874 plankton samples, 438 were positive for cephalopod paralarvae (n = 2116), which were identified to the lowest taxonomic level possible, totaling 15 taxa belonging to 11 families. Richness and diversity indexes (Shannon-Wiener, Simpson, Pielou’s evenness) revealed a cross-shelf gradient, independent of season and latitude. Abundance k-dominance curves were consistent with this depth-related trend, resulting in high values of k-dominance for the inner shelf during both summer and winter. Two major assemblages were identified by cluster analyses: an inner shelf and a mid-outer shelf. During summer, the inner shelf assemblage was composed of neritic Loliginidae Lesueur, 1821 and epipelagic Argonautidae Tryon, 1879, while in winter, benthic Octopodidae Orbigny, 1840 replaced Argonautidae in importance. These data reveal a remarkable difference in Argonautidae and Octopodidae paralarvae abundance, suggesting a seasonal reproductive pattern for these cephalopods in the SBB. Mesopelagic Enoploteuthidae Pfeffer, 1900 and Ommastrephidae Steenstrup, 1857 characterized the mid-outer shelf assemblages both in summer and winter. Although based on a higher taxonomic level, the distribution of cephalopod paralarva families reflected not only oceanographic patterns of the SBB but also their adaptations and reproductive strategies. In particular, the cross-shelf gradient in cephalopod biodiversity reflects a more dynamic oceanographic conditions in inner shelf compared with mid-outer shelf ecosystems.

Marine annelids in the subfamily Calamyzinae (family Chrysopetalidae) are either symbiotic or free-living forms that have been mainly reported from deep-sea chemosynthetic systems. Symbiotic calamy...

A new species of parasitic Aggregata, Aggregata sinensis n. sp., is described from the octopuses Amphioctopus fangsiao (d'Orbigny, 1839-1841) and Octopus minor (Sasaki, 1920) (Mollusca: Octopodidae) in China based on morphological data and 18S ribosomal RNA (rRNA) gene sequences. The sexual gamogonic and sporogonic stages of the parasite were observed under light microscope. The sizes of oocysts were 207.35-618.74 μm in length and were 136.31-420.68 μm in width. Oocysts were fully sporulated and were shaped spherically or irregularly. Mature sporocysts within oocysts were spherical or slightly subovoid and were 19.42-22.32 μm in length and 19.12-21.55 μm in width. Sporozoites were typically spiral within sporocysts and were 17.81-24.90 μm long and 2.05-3.42 μm wide. Molecular phylogenetic analysis constructed using the 18S rRNA gene sequences supports the morphological classification that our species is placed within the genus Aggregata. Moreover, the sequence belonged to the genus Aggregata. However, the 18S rRNA gene sequence of Ag. sinensis was significantly different from that of other Aggregata available currently. Ag. sinensis is the first two-host parasitic species of Aggregata reported from definitive host Am. fangsiao and O. minor and is the only species of the genus Aggregata known in Western Pacific waters.

This study aimed to explore different substances (or cold sea water) as potential anesthetic agents to facilitate short-term handling in Octopus maya juveniles. We investigated oxygen consumption before (baseline), during (first 600 s of exposure) and after anesthesia (recovery) of octopuses (n = 98; 1.67 ± 0.5 g) exposed to cold sea water (SW; 11 and 13°C), ethanol (EtOH; 0.5; 1.5 and 3.0%), magnesium chloride (MgCl2; 0.75; 1.5 and 3.75%), ethanol combined with magnesium chloride (Mix; 1.5:0.75%; 0.75:1.13%; and 2.25:0.37%) and clove oil (0.15 mL L–1). After exposure, the animals were handled for 180 s (exposed to air) and weighted. Two experimental groups not exposed to anesthetics (with or without handling) were also evaluated. The criteria for general anesthesia were analysed. Times of induction and recovery, incidence of attack response after recovery and possible longer-term effects of repeated general anesthesia on growth and mortality of the octopuses were evaluated. During anesthesia, O. maya juveniles exposed to SW (11 and 13°C), EtOH (0.5; 1.5 and 3.0%), Mix (0.75:1.13%), and clove oil, presented a significant decrease on oxygen consumption. In animals exposed to different concentrations of EtOH and Mix 0.75:1.13%, this decrease was registered after an increase on oxygen consumption. Animals exposed to MgCl2 did not show significant changes on oxygen consumption, except for animals exposed MgCl2 3.75%, which showed a significant increase on oxygen consumption. At the end of recovery, except for octopuses exposed to clove oil and MgCl2 0.75%, the values of oxygen consumption observed were comparable to the ones registered during baseline. Animals exposed to SW 11°C, EtOH 3.0%, Mix 1.5:0.75% and MgCl2 3.75% fulfilled the criteria defined for general anesthesia. Exposure to MgCl2 (all concentrations), SW 13°C and clove oil reduced or inhibited the incidence of attack response after recovery. Except for animals exposed to clove oil, growth of the juveniles was not affected by the exposure to the different substances. Short-term handling (180 s) of O. maya juveniles can eventually be carried out without anesthesia. However, to facilitated handling, we suggest the use of EtOH 3.0% or cold sea water 11°C.

In the Atlantic Ocean, Octopus insularis Leite and Haimovici, 2008 inhabits warm and shallow habitats, where it is one of the main targets of cephalopod fisheries. Considering the current trend of increase of increasing sea-water temperature, warm-water species are expected to expand their geographic distribution range. Ecological niche modeling (ENM) is an important tool to help describe likely changes in geographic distribution patterns of a species in many climatic scenarios. To evaluate the changes of O. insularis distribution over time, the Maximum Entropy approach was used, which estimated a suitable climatic niche for Octopus under five scenarios of global climate changes. Six environmental layers were chosen to model the modern suitable climatic niche of O. insularis and four variables were used for past and future scenarios. The ENM in different climatic scenarios showed good validation and pointed out an increase of the suitable niche for O. insularis settlement, from Last Glacial Maximum (21 Kya) up to future scenarios. In the future projections, the availability of species suitable niche will potentially increase in Tropical Atlantic compared to the current distribution. In addition, the modeling pointed out the possibility of an expansion from the species current range to Temperate Northern Atlantic, Temperate South America, and Temperate South Africa. This may cause potential threats, such as possible extinction of endemic species, habitat displacement of native octopuses, reorganizations in the trophic chain.

Octopus minor is widely distributed along the northern coast of China. To date, there is little information on the prey selection process of this species. To understand this process, several experiments were carried out. Three types of bivalves, namely, Ruditapes philippinarum, Mactra chinensis, and Mytilus galloprovincialis, were used to observe the prey selection of O. minor and to analyze the potential causes of prey selection from three aspects: prey profitability, adductor muscle tension and handling time. Under single-prey conditions, we found that the average (±SD) predation rates of O. minor on R. philippinarum, M. chinensis, and M. galloprovincialis were 1.73±0.50, 1.27±0.42, and 0.8±0.2/d, respectively. Under different prey combinations, octopods actively selected one type of prey over the other(s), and the order of prey preference was R. philippinarum, followed by M. chinensis and lastly M. galloprovincialis. Furthermore, the shells of the consumed prey showed that O. minor only consumed bivalves by pulling them apart since there was no evidence of drill holes on the shells. The prey selection of O. minor was related to the prey profitability and handling time; O. minor appeared to select preys with a higher profitability and a shorter handling time. However, the difficulty in opening the bivalve was not consistent with the prey preference of the octopods. These results suggest that O. minor prefers to consume R. philippinarum possibly due to a high profitability and a short handling time that supports the optimum Foraging Theory.

Here, we evaluate the so-called Thorson's rule, which posits that direct-development and larger eggs are favored toward the poles in marine organisms and whose validity been the subject of considerable debate in the literature, combining an expanded phenotypic dataset encompassing 60 species of benthic octopuses with a new molecular phylogeny. Phylogenetic reconstruction shows two clades: clade 1 including species of the families Eledonidae, Megaleledonidae, Bathypolypodidae, and Enteroctopodidae, and clade 2 including species of Octopodidae. Egg size, development mode, and all environmental variables exhibited phylogenetic signal, partly due to differences between the two clades: whereas most species in clade 1 inhabit cold and deep waters, exhibit large eggs and hatchling with holobenthic development, species from clade 2 inhabit tropical-temperate and shallow waters, evolved small eggs, and generally exhibit merobenthic development. Phylogenetic regressions show that egg size exhibits a conspicuous latitudinal cline, and that both egg size and development mode vary with water temperature. Additionally, analyses suggest that egg size is constrained by body size in lineages with holobenthic development. Taken together, results suggest that the variation in egg size and development mode across benthic octopuses is adaptive and associated with water temperature, supporting Thorson's rule in these organisms.

Octopus is the most abundant genus in the family Octopodidae and accounts for more than half of the total cephalopod landing in neritic fisheries. A taxonomic problem still exists due to synonymous scientific names and limited genetic information. The cephalopod beak is a stable structure that allows an effective solution to the problem of the species and stock identification. Beak shape variation has been more widely considered than beak measurements in recent years. In this study, with the beak as the experimental material, we combined geometric morphometrics (GM) with machine learning methods and compared the discrimination results obtained by traditional and GM methods in four Chinese neritic octopus species (Amphioctopus fangsiao, Amphioctopus ovulum, Octopus minor and Octopus sinensis). According to our analyses, Octopus sinensis has the larger beak size [both upper beak (UB) and lower beak (LB)] than other species. The results of ANOVA showed that all beak measurements differed significantly among the four species. Significant differences in both UB and LB shapes among four species were identified in MANOVA analysis based on the GM method. The results of GM-based discriminant analysis were better than those of traditional measurements, and machine learning methods also showed the higher correct classification rates than linear discriminant analysis. GM is a useful method to reconstruct the shape cephalopod beak and can also effectively distinguish different species. We should improve classification accuracy with machine learning methods for determining species structure in the future.

Octopusminor is an economically important resource commonly found in Chinese coastal waters. The nuclear gene (RD and ODH) approach of investigation has not reported in this species. Rhodopsin (RD) and octopine dehydrogenase (ODH) genes were used to elaborate the genetic structure collected from eight localities ranging from the northern to the southern coast of China. In total, 118 individuals for the RD gene and 108 for the ODH were sequenced. Overall (RD and ODH) genes resulted in high (0.741±0.032; 0.805±0.038) haplotype and low nucleotide (0.01261±0.00165; 0.00747±0.00086) diversity. Molecular variance displayed higher values among the populations and lower values within the population where the fixation index FST denoted 0.880 and 0.584 in RD and ODH genes respectively. The Dongshan population clustered separately in a phylogenetic tree as in the haplotype networking assessment. The current data suggests that the Dongshan population needs separate management.