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Development of eyes during the embryonic development and early life stage. a Embryos at stage X-XI. b Embryos at stage XI-XII. c Embryos at stage XII-XIII. d Embryos at stage XIII-XIV. e
Source publication
Amphioctopus fangsiao is an important fishery resource in northern coastal China, and there is an interest to develop its commercial cultivation under controlled conditions. In this study, we describe the embryonic development of A. fangsiao from eggs to hatchlings, focusing on the formation of the mantle, eyes and arms. Results indicate that this...
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... stage XV-XVII, chromatophores of varied colors distributed widely around the head and dorsal side of arms and mantle. The mantle sac had grown larger, so the embryo already became a truly larval form from stage XV. The primary lid fold contracted over the eye, and only an oval opening remained during the proceeding stage (Fig. ...
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... stage XIX, the area surrounding the eye lens became a fully transparent skin (Fig. 3f), with a function as eyelid or cornea, and it did not seem to hinder the visual function, but protected the eye. The external yolk sac was nearly consumed and covered by arms. The embryo was ready to hatch and might come out from the envelope by external Fig. 1 Embryonic stages (from I to XX) of Amphioctopus fangsiao. ap animal pole, ar ...
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... of stage IX, the eye diameter was always longer than the mantle length and width, and the relationships lasted until stage XIV (Table 1). As the brain develops from the region between eyes, it can be inferred that the brain development of embryo might be a priority compared with other organs. The retinal pigment appeared yellowish at stage X-XI (Fig. 3a) and gradually deepens in pigmentation, turning from yellowish to yellow (Fig. 3b), red (Fig. 3c), dark-red (Fig. 3d) and black ( Fig. 3e-i). At stage XV, the primary lid fold, with only a circular opening remaining, covered over the eye and the dorsal ocular edge, could not reach the ventral side until hatching (day 1-7, Figs. 2d-f, ...
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... and the relationships lasted until stage XIV (Table 1). As the brain develops from the region between eyes, it can be inferred that the brain development of embryo might be a priority compared with other organs. The retinal pigment appeared yellowish at stage X-XI (Fig. 3a) and gradually deepens in pigmentation, turning from yellowish to yellow (Fig. 3b), red (Fig. 3c), dark-red (Fig. 3d) and black ( Fig. 3e-i). At stage XV, the primary lid fold, with only a circular opening remaining, covered over the eye and the dorsal ocular edge, could not reach the ventral side until hatching (day 1-7, Figs. 2d-f, 3e-g). Afterwards, about 24 days after hatchling (Figs. 2g, 3h), both the dorsal and ...
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... lasted until stage XIV (Table 1). As the brain develops from the region between eyes, it can be inferred that the brain development of embryo might be a priority compared with other organs. The retinal pigment appeared yellowish at stage X-XI (Fig. 3a) and gradually deepens in pigmentation, turning from yellowish to yellow (Fig. 3b), red (Fig. 3c), dark-red (Fig. 3d) and black ( Fig. 3e-i). At stage XV, the primary lid fold, with only a circular opening remaining, covered over the eye and the dorsal ocular edge, could not reach the ventral side until hatching (day 1-7, Figs. 2d-f, 3e-g). Afterwards, about 24 days after hatchling (Figs. 2g, 3h), both the dorsal and ventral sides ...
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... stage XIV (Table 1). As the brain develops from the region between eyes, it can be inferred that the brain development of embryo might be a priority compared with other organs. The retinal pigment appeared yellowish at stage X-XI (Fig. 3a) and gradually deepens in pigmentation, turning from yellowish to yellow (Fig. 3b), red (Fig. 3c), dark-red (Fig. 3d) and black ( Fig. 3e-i). At stage XV, the primary lid fold, with only a circular opening remaining, covered over the eye and the dorsal ocular edge, could not reach the ventral side until hatching (day 1-7, Figs. 2d-f, 3e-g). Afterwards, about 24 days after hatchling (Figs. 2g, 3h), both the dorsal and ventral sides of eyelid could ...
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... As the brain develops from the region between eyes, it can be inferred that the brain development of embryo might be a priority compared with other organs. The retinal pigment appeared yellowish at stage X-XI (Fig. 3a) and gradually deepens in pigmentation, turning from yellowish to yellow (Fig. 3b), red (Fig. 3c), dark-red (Fig. 3d) and black ( Fig. 3e-i). At stage XV, the primary lid fold, with only a circular opening remaining, covered over the eye and the dorsal ocular edge, could not reach the ventral side until hatching (day 1-7, Figs. 2d-f, 3e-g). Afterwards, about 24 days after hatchling (Figs. 2g, 3h), both the dorsal and ventral sides of eyelid could contract freely, with an ...
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... covered over the eye and the dorsal ocular edge, could not reach the ventral side until hatching (day 1-7, Figs. 2d-f, 3e-g). Afterwards, about 24 days after hatchling (Figs. 2g, 3h), both the dorsal and ventral sides of eyelid could contract freely, with an oval and elongate slit remaining, which was miniature-like adults in morphology (Fig. ...
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... A. fangsiao (N = 50, male:female = 1:1, wet body weight = 82.33 ± 54.13 g) were captured in the coastal of Lianyungang, Jiangsu province, China (34°N, 119°E), then transported to Jiaxin Aquaculture Firm and finally maintained in 2.2 m 3 aerated cement pools (4 m of length × 1.1 m of width × 0.5 m of water depth). The clam Ruditapes philippinarum was used as food (feed ratio = 5% body weight day −1 ) for octopuses during the maintenance period until they ceased to eat. ...
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... stage XV-XVII, chromatophores of varied colors distributed widely around the head and dorsal side of arms and mantle. The mantle sac had grown larger, so the embryo already became a truly larval form from stage XV. The primary lid fold contracted over the eye, and only an oval opening remained during the proceeding stage (Fig. ...
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... stage XIX, the area surrounding the eye lens became a fully transparent skin (Fig. 3f), with a function as eyelid or cornea, and it did not seem to hinder the visual function, but protected the eye. The external yolk sac was nearly consumed and covered by arms. The embryo was ready to hatch and might come out from the envelope by external Fig. 1 Embryonic stages (from I to XX) of Amphioctopus fangsiao. ap animal pole, ar ...
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... of stage IX, the eye diameter was always longer than the mantle length and width, and the relationships lasted until stage XIV (Table 1). As the brain develops from the region between eyes, it can be inferred that the brain development of embryo might be a priority compared with other organs. The retinal pigment appeared yellowish at stage X-XI (Fig. 3a) and gradually deepens in pigmentation, turning from yellowish to yellow (Fig. 3b), red (Fig. 3c), dark-red (Fig. 3d) and black ( Fig. 3e-i). At stage XV, the primary lid fold, with only a circular opening remaining, covered over the eye and the dorsal ocular edge, could not reach the ventral side until hatching (day 1-7, Figs. 2d-f, ...
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... and the relationships lasted until stage XIV (Table 1). As the brain develops from the region between eyes, it can be inferred that the brain development of embryo might be a priority compared with other organs. The retinal pigment appeared yellowish at stage X-XI (Fig. 3a) and gradually deepens in pigmentation, turning from yellowish to yellow (Fig. 3b), red (Fig. 3c), dark-red (Fig. 3d) and black ( Fig. 3e-i). At stage XV, the primary lid fold, with only a circular opening remaining, covered over the eye and the dorsal ocular edge, could not reach the ventral side until hatching (day 1-7, Figs. 2d-f, 3e-g). Afterwards, about 24 days after hatchling (Figs. 2g, 3h), both the dorsal and ...
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... lasted until stage XIV (Table 1). As the brain develops from the region between eyes, it can be inferred that the brain development of embryo might be a priority compared with other organs. The retinal pigment appeared yellowish at stage X-XI (Fig. 3a) and gradually deepens in pigmentation, turning from yellowish to yellow (Fig. 3b), red (Fig. 3c), dark-red (Fig. 3d) and black ( Fig. 3e-i). At stage XV, the primary lid fold, with only a circular opening remaining, covered over the eye and the dorsal ocular edge, could not reach the ventral side until hatching (day 1-7, Figs. 2d-f, 3e-g). Afterwards, about 24 days after hatchling (Figs. 2g, 3h), both the dorsal and ventral sides ...
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... stage XIV (Table 1). As the brain develops from the region between eyes, it can be inferred that the brain development of embryo might be a priority compared with other organs. The retinal pigment appeared yellowish at stage X-XI (Fig. 3a) and gradually deepens in pigmentation, turning from yellowish to yellow (Fig. 3b), red (Fig. 3c), dark-red (Fig. 3d) and black ( Fig. 3e-i). At stage XV, the primary lid fold, with only a circular opening remaining, covered over the eye and the dorsal ocular edge, could not reach the ventral side until hatching (day 1-7, Figs. 2d-f, 3e-g). Afterwards, about 24 days after hatchling (Figs. 2g, 3h), both the dorsal and ventral sides of eyelid could ...
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... As the brain develops from the region between eyes, it can be inferred that the brain development of embryo might be a priority compared with other organs. The retinal pigment appeared yellowish at stage X-XI (Fig. 3a) and gradually deepens in pigmentation, turning from yellowish to yellow (Fig. 3b), red (Fig. 3c), dark-red (Fig. 3d) and black ( Fig. 3e-i). At stage XV, the primary lid fold, with only a circular opening remaining, covered over the eye and the dorsal ocular edge, could not reach the ventral side until hatching (day 1-7, Figs. 2d-f, 3e-g). Afterwards, about 24 days after hatchling (Figs. 2g, 3h), both the dorsal and ventral sides of eyelid could contract freely, with an ...
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... covered over the eye and the dorsal ocular edge, could not reach the ventral side until hatching (day 1-7, Figs. 2d-f, 3e-g). Afterwards, about 24 days after hatchling (Figs. 2g, 3h), both the dorsal and ventral sides of eyelid could contract freely, with an oval and elongate slit remaining, which was miniature-like adults in morphology (Fig. ...
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... A. fangsiao (N = 50, male:female = 1:1, wet body weight = 82.33 ± 54.13 g) were captured in the coastal of Lianyungang, Jiangsu province, China (34°N, 119°E), then transported to Jiaxin Aquaculture Firm and finally maintained in 2.2 m 3 aerated cement pools (4 m of length × 1.1 m of width × 0.5 m of water depth). The clam Ruditapes philippinarum was used as food (feed ratio = 5% body weight day −1 ) for octopuses during the maintenance period until they ceased to eat. ...
Citations
... The period of embryonic development and thus the duration of maternal care varies among species and with ambient seawater temperatures and generally range from 20 to 160 days (Ignatius & Srinivasan, 2006;Mangold, 1983;Rosas et al., 2014;Spreitzenbarth & Jeffs, 2021;Uriarte et al., 2016). This is also the case for the webfoot octopus, Amphioctopus fangsiao, with an embryonic development time of <90 days (Jiang et al., 2020a;Tziouveli & Yokoyama, 2017;Yamamoto & Abe, 2022) and for the East Asian common octopus, Octopus sinensis, with an embryonic development time of <69 days (Hamasaki & Morioka, 2002). ...
... Amphioctopus fangsiao and O. sinensis can be found in coastal waters of the Western Pacific and both have been harvested and consumed in Asia for centuries (Jereb et al., 2014;Sauer et al., 2019). Amphioctopus fangsiao is a holobenthic octopus with a maximum size <200 g and produces small egg clutches of a few hundred embryos, which develop directly into juveniles (Jereb et al., 2014;Jiang et al., 2020a;Pang et al., 2020). Octopus sinensis is a mediumsized merobenthic octopus that can reach over 3000 g and produces large egg clutches of up to 500,000 embryos, which have an indirect development from paralarvae through a settlement stage before they become fully benthic juveniles (Jereb et al., 2014;Joll, 1976;Mangold, 1983;Suzumura et al., 2022). ...
... Octopus sinensis is a mediumsized merobenthic octopus that can reach over 3000 g and produces large egg clutches of up to 500,000 embryos, which have an indirect development from paralarvae through a settlement stage before they become fully benthic juveniles (Jereb et al., 2014;Joll, 1976;Mangold, 1983;Suzumura et al., 2022). Recent decline in annual catches for both species because of overfished wild stocks has stimulated research on various aspects of their biology, habitat requirements, reproduction, and commercial culture (Cai et al., 2007;Dan et al., 2019;Hamasaki et al., 1991;Hamasaki & Takeuchi, 2001;Jiang et al., 2020aJiang et al., , 2020bPang et al., 2020;Tziouveli & Yokoyama, 2017;Zheng et al., 2023). ...
Replicating maternal care and incubating octopus embryos artificially is advantageous to improve access to embryonic stages, split and share broods, and reduce the required space to culture large quantities of embryos. However, without female care and adequate rearing systems, the risk of bacterial and fungal infections can be high. This study evaluated the potential effects of low-concentration sodium hypochlo-rite (NaOCl) as a disinfectant on embryonic survival, hatchling survival, and growth. Embryos of a holobenthic octopus, Amphioctopus fangsiao, and of a merobenthic octopus, Octopus sinensis, were disinfected with 0.004% NaOCl for 3 min either once at the start (IB), at the start and halfway point (RB), and without disinfection (control). Survival of A. fangsiao embryos differed among treatments initially, but the final number of hatchings did not differ among treatments. No differences in the final survival for O. sinensis embryos were observed among the three treatments. Wet weight and growth for A. fangsiao juveniles did not differ among treatments at any point. In contrast, initial and final dry weight for
... As an important commercial species, Amphioctopus fangsiao (Cephalopoda: Octopodidae) is widely distributed along the coast of China, which is very popular among consumers due to its fresh flavor and nutritional value (Jiang et al., 2020b;Zheng et al., 2023b). It is a typical shallow-water species, that is more vulnerable to environmental factors such as temperature changes (Zheng et al., 2022a). ...
... The life span of A. fangsiao is only one year and dies after it lays eggs (Zheng et al., 2023a). In the natural environment, A. fangsiao usually lays eggs in May, and the embryos hatch after more than a month of development (Jiang et al., 2020a, 2020b, Zheng et al., 2022b. During this period, there may be multiple dynamic changes in sea temperature (Zhang et al., 2023). ...
... The hatching rate and hatching time of all treated groups (100 eggs per group) were recorded. In previous studies, Naef (1928) and Jiang et al. (2020b) defined and described twenty embryonic stages of A. fangsiao. The embryo had absorbed all of the external yolk and hatched as a miniature-like adult in morphology at stage XX, known as newborn hatchings. ...
... During this crucial period, temperature exerts a particularly influential role in embryonic development and incubation duration. Several studies on cephalopods have demonstrated an inverse relationship between the duration of embryonic development and temperature 2 of 20 within a specific range [4,5]. Furthermore, temperature also significantly impacts the mortality or survival rate of cephalopod embryos. ...
... Especially in cephalopods, according to Uriarte (2012) [58] and Nande (2018) [59], a shorter embryonic development and hatching period due to an increase in temperature allows earlier hatching of octopuses, as well as faster growth and reaching of reproductive age. Embryos of Amphioctopus fangsiao hatched successfully at 40, 30, and 24 days post fertilization (dpf) at temperatures of 18 • C, 21 • C, and 24 • C, respectively [4]. Similar results were observed in this study: compared to the Ctrl group, the overall development time of embryos in the low-temperature group was delayed by approximately 9 days, with significant delays occurring at the Early blastula and Heart beating stages. ...
... In Coelomactra antiquata, fertilized eggs developed to the larval stage after 20 h at a water temperature of 15.5 ± 0.5 • C but ceased to develop, while at a temperature of 28 ± 0.5 • C, the fertilized eggs became deformed [63]. Similarly, in A. fangsiao, where 25.9% of eggs incubated at a lower temperature (24 • C), the eggs failed to undergo inversion from the animal pole to the vegetal pole [4]. In the present study, malformations caused by low temperature (18 • C) primarily occurred during the stages of Optic vesicle and Heart beating, resulting in shortened arms and disordered external organ development. ...
Temperature is a crucial environmental factor that affects embryonic development, particularly for marine organisms with long embryonic development periods. However, the sensitive period of embryonic development and the role of autophagy/apoptosis in temperature regulation in cephalopods remain unclear. In this study, we cultured embryos of Sepiella japonica, a typical species in the local area of the East China Sea, at different incubation temperatures (18 °C, 23 °C, and 28 °C) to investigate various developmental aspects, including morphological and histological characteristics, mortality rates, the duration of embryonic development, and expression patterns of autophagy-related genes (LC3, BECN1, Inx4) and apoptosis marker genes (Cas3, p53) at 25 developmental stages. Our findings indicate that embryos in the high-temperature (28 °C) group had significantly higher mortality and embryonic malformation rates than those in the low-temperature (18 °C) group. Furthermore, high temperature (28 °C) shortened the duration of embryonic development by 7 days compared to the optimal temperature (23 °C), while low temperature (18 °C) caused a delay of 9 days. Therefore, embryos of S. japonica were more intolerant to high temperatures (28 °C), emphasizing the critical importance of maintaining an appropriate incubation temperature (approximately 23 °C). Additionally, our study observed, for the first time, that the Early blastula, Blastopore closure, and Optic vesicle to Caudal end stages were the most sensitive stages. During these periods, abnormalities in the expression of autophagy-related and apoptosis-related genes were associated with higher rates of mortality and malformations, highlighting the strong correlation and potential interaction between autophagy and apoptosis in embryonic development under varying temperature conditions.
... During this crucial period, temperature exerts a particularly influential role in embryonic development and incubation duration. Several studies on cephalopods have demonstrated an inverse relationship between the duration of embryonic development and temperature within a specific range (Jiang et al., 2020;Ramiro et al., 2020;Repolho et al., 2014). Furthermore, temperature also significantly impacts the mortality or survival rate of cephalopod embryos (Jiang et al., 2013;Ramiro et al., 2020). ...
... Especially in cephalopods, according to Uriarte (2012) and Nande (2018), a shorter embryonic development and hatching period due to an increase in temperature would allow octopuses to hatch earlier, grow faster, and reach reproductive age. Embryos of Amphioctopus fangsiao hatched successfully at 40, 30, and 24 days postfertilization (dpf) at temperatures of 18 °C, 21 °C, and 24 °C, respectively (Jiang et al., 2020). Similar results were observed in this study: compared to the Ctrl group, the overall development time of embryos in the low-temperature group was delayed by approximately 9 days, with significant delays occurring at the Early blastula and Heart beating stages. ...
... In Coelomactra antiquata, fertilized eggs developed to the larval stage after 20 hours at a water temperature of 15.5 ± 0.5 °C but ceased to develop, while at a temperature of 28 ± 0.5 °C, the fertilized eggs became deformed (Liu and Chen, 1998). Similarly, in A. fangsiao, where 25.9% of eggs incubated at a lower temperature (24 °C) failed to undergo inversion from the animal pole to the vegetal pole (Jiang et al., 2020). In the present study, malformations caused by low temperature (18 °C) primarily occurred during the stages of Optic vesicle and Heart beating, resulting in shortened arms and disordered external organ development. ...
Temperature is a crucial environmental factor that affects embryonic development, particularly for marine organisms with long embryonic development periods. However, the sensitive period of embryonic development and the role of autophagy/apoptosis in temperature regulation in cephalopods, enigmatic creatures, remain unclear. In this study, we cultured embryos of Sepiella japonica, a typical species in the local area of the East China Sea, at different incubation temperatures (18 ℃, 23 ℃, and 28 ℃) to investigate various developmental aspects, including morphological and histological characteristics, mortality rates, the duration of embryonic development, and expression patterns of autophagy-related genes (LC3, BECN1, Inx4) and apoptosis marker genes (Cas3, p53) at 25 developmental stages. Our findings indicate that embryos in the high-temperature (28 ℃) group had significantly higher mortality and embryonic malformation rates than those in the low-temperature (18 ℃) group. Furthermore, high temperature (28 ℃) shortened the duration of embryonic development by 7 days compared to the optimal temperature (23 ℃), while low temperature (18 ℃) caused a delay of 9 days. Therefore, embryos of S. japonica were more intolerant to high temperatures (28 ℃), emphasizing the critical importance of maintaining an appropriate incubation temperature (approximately 23 ℃). Additionally, our study observed, for the first time, that the Early blastula, Blastopore closure, and Optic vesicle to Caudal end stages were the most sensitive stages. During these periods, abnormalities in the expression of autophagy-related and apoptosis-related genes were associated with higher rates of mortality and malformations, highlighting the strong correlation and potential interaction between autophagy and apoptosis in embryonic development under varying temperature conditions.
... P and B indicate posthatching lifestyles of each species (P, pelagic; B, benthic (Naef, 1928). In A. fangsiao, embryonic stages were previously investigated (Jiang et al., 2020). The axes of each arm were defined as shown in Figure 1i (Nödl et al., 2015). ...
Morphologies of animal appendages are highly diversified depending on animal lifestyles. In cephalopods (Mollusca, Cephalopoda), an individual possesses multiple arms that contribute to elaborate behaviors, and suckers on them enable various arm functions. In octopus hatchlings, arm and sucker morphologies can be divided into two different types due to alternative posthatching lifestyles, that is, pelagic or benthic lifestyles, although the underlying developmental differences have yet to be elucidated. In this study, therefore, detailed developmental processes of arms and suckers were observed during embryogenesis in two different octopus species, Octopus parvus and Amphioctopus fangsiao, showing pelagic and benthic posthatching lifestyles, respectively. In O. parvus, sucker formation stopped at a relatively early stage in which three suckers on an arm were produced. In addition, at late embryonic stages, cell proliferation was hardly detected in whole arms, while in A. fangsiao, sucker production continued throughout embryogenesis and cell proliferation also remained active in whole arms even in the late stages. Therefore, although further investigations in other octopus species are required, it is suggested that in octopus evolution, the developmental program of suckers has been modified in accordance with the acquisition of a novel lifestyle.
... The wild and mature individuals of A. fangsiao were collected in Lianyungang (N 34°, E 119°, Jiangsu province, China), and species identity was validated by the sequencing of the mitochondrial COI gene (UJY97108). The octopuses were temporarily maintained in a 2-L seawater tank at 18°C as described before [45], and individuals were anesthetized using MgCl 2 (>10 g/L) before use. The muscle of arms was used for genome sequencing. ...
Background
Coleoid cephalopods have distinctive neural and morphological characteristics compared to other invertebrates. Early studies reported massive genomic rearrangements occurred before the split of octopus and squid lineages (Proc Natl Acad Sci U S A 116:3030-5, 2019), which might be related to the neural innovations of their brain, yet the details remain elusive. Here we combine genomic and single-nucleus transcriptome analyses to investigate the octopod chromosome evolution and cerebral characteristics.
Results
We present a chromosome-level genome assembly of a gold-ringed octopus, Amphioctopus fangsiao , and a single-nucleus transcriptome of its supra-esophageal brain. Chromosome-level synteny analyses estimate that the chromosomes of the ancestral octopods experienced multiple chromosome fission/fusion and loss/gain events by comparing with the nautilus genome as outgroup, and that a conserved genome organization was detected during the evolutionary process from the last common octopod ancestor to their descendants. Besides, protocadherin, GPCR, and C2H2 ZNF genes are thought to be highly related to the neural innovations in cephalopods (Nature 524:220–4, 2015), and the chromosome analyses pinpointed several collinear modes of these genes on the octopod chromosomes, such as the collinearity between PCDH and C2H2 ZNF, as well as between GPCR and C2H2 ZNF. Phylogenetic analyses show that the expansion of the octopod protocadherin genes is driven by a tandem-duplication mechanism on one single chromosome, including two separate expansions at 65 million years ago (Ma) and 8–14 Ma, respectively. Furthermore, we identify eight cell types (i.e., cholinergic and glutamatergic neurons) in the supra-esophageal brain of A. fangsiao , and the single-cell expression analyses reveal the co-expression of protocadherin and GPCR in specific neural cells, which may contribute to the neural development and signal transductions in the octopod brain.
Conclusions
The octopod genome analyses reveal the dynamic evolutionary history of octopod chromosomes and neural-related gene families. The single-nucleus transcriptomes of the supra-esophageal brain indicate their cellular heterogeneities and functional interactions with other tissues (i.e., gill), which provides a foundation for further octopod cerebral studies.
... The characteristics of small-scale activity areas and territorial nature allow they can indicate the quality of the coastal habitat environments Sillero-Ríos et al., 2018). Moreover, as generalist predators, octopuses are more likely to accumulate pollutants in their bodies, such as microplastics and heavy metals, both from the prey and the environment (Mangold, 1983;Bo et al., 2020;García et al., 2002;Jiang et al., 2020b). They thus have been proven as a potential indicator organism of environmental pollution (Raimundo et al., 2010;Semedo et al., 2014;Sillero-Ríos et al., 2018). ...
... It is necessary to better understand the potential impact of microplastics on cephalopods using synthetical studying methods. As an important economic species of cephalopods, Octopus Amphioctopus fangsiao is not only widely distributed in the northwest Pacific Ocean, but also a potentially suitable species for industrial aquaculture (Jiang et al., 2020b). Lately, many studies have focused on fishing, farming and classification of A. fangsiao (Jiang et al., 2020a;Tang et al., 2021;Bao et al., 2022). ...
Microplastics are broadly used and among the most studied environmental pollutants due to their potential impacts on organisms and human health. Amphioctopus fangsiao (Cephalopoda: Octopodidae) is an important commercial species in the Pacific Northwest and is very popular among consumers owing to its rich nutritional value and fresh flavor. However, the toxic effects of microplastic exposed on A. fangsiao, including phenotypical effect and underlying molecular mechanism, remain limited. In this study, the octopus A. fangsiao were exposed to microplastics (polystyrene microplastics, Micro-PS) at concentrations of 100 and 1000 μg/L for 21 days, and then the physiological response, histopathological analysis, biomarkers of oxidative stress and glycolipid metabolism, microbiome perturbations and transcriptomic profiles in the intestines were performed. Results demonstrated that Micro-PS exposure had distinct adverse effects on the food intake of A. fangsiao. Histological analysis revealed that Micro-PS exposure has resulted in histopathological damage, thus causing early inflammation of the intestine. Oxidative stresses, metabolic disorders and microbiome perturbations were also detected in the intestine of A. fangsiao based on physiological biomarkers and microbiome analyses. Moreover, transcriptome analysis detected the differentially expressed genes (DEGs) and significantly enriched KEGG pathways in response to oxidative stress, glycolipid metabolism, DNA damage and transmembrane transport of intestinal cells, revealing distinct toxic effects at the molecular level. In summary, Micro-PS exposure has a strong impact on the intestines of A. fangsiao. For the first time, this study uses multiple approaches based on the physiological and biochemical response as well as transcriptional regulation analysis. The first assessment of the toxic impact of this species under Micro-PS exposure is also reported.
... To date, multiple gyri in the vertical lobe (VL), which is functionally equivalent to the vertebrate cortex, have been partially described in approximately 20 octopus species. [8][9][10][11][12][13][14][15][16][17][18] Our current knowledge of octopus neuroscience and associated complex behavior is predominantly derived from a large number of studies on a primarily nocturnal species, Octopus vulgaris. 10,11,14,[19][20][21][22][23][24][25][26][27][28][29] While some of what we know around biology, ecology, and physiology has also been obtained from another large species, Octopus cyanea, [30][31][32][33][34][35][36][37][38] knowledge of its neuroanatomy was absent prior to this study. ...
... 11,15,24,48,57,[62][63][64][65][66] We chose a comparative approach and investigated four species of octopodiform cephalopods that represent phylogenetically distinct groups and that exhibit different life modes, including the deep-sea Vampyroteuthis infernalis, a solitary nocturnal Hapalochlaena fasciata, and two diurnal reef dwellers, Abdopus capricornicus and O. cyanea ( Figure 1). In addition to these newly described species, another four coastal octopus species were selected from published literature 11,15,17,18 and included for further analyses where comparative data exist (Table S2). Observations on the relative enlargement of brain lobes, number of VL gyri, and brain folding are included in an extended comparison of species, relative to ecology and lifestyle as well as phylogeny based on existing molecular data. ...
... 11,47,57,70,90 Three phylogenetic clades of coastal octopus (the vulgaris, Amphioctopus-Hapalochlaena, and Callistoctopus groups defined by Guzik et al. 91 ) that possess the bean-shaped OPL are predominantly active at night (Figure 7; Table S3). 13,15,17,18,20,22,26,[67][68][69]91 After dusk, the light level at the ocean surface drops by 8 log units compared to mid-day. 92 The eyes of many octopus species are large with long rhabdomeric photoreceptors, dynamic movement of screening pigments, and motile pupils, all adaptations required to increase sensitivity. ...
Octopods are masters of camouflage and solve complex tasks, and their cognitive ability is said to approach that of some small mammals. Despite intense interest and some research progress, much of our knowledge of octopus neuroanatomy and its links to behavior and ecology comes from one coastal species, the European common octopus, Octopus vulgaris. Octopod species are found in habitats including complex coral reefs and the relatively featureless mid-water. There they encounter different selection pressures, may be nocturnal or diurnal, and are mostly solitary or partially social. How these different ecologies and behavioral differences influence the octopus central nervous system (CNS) remains largely unknown. Here we present a phylogenetically informed comparison between diurnal and nocturnal coastal and a deep-sea species using brain imaging techniques. This study shows that characteristic neuroanatomical changes are linked to their habits and habitats. Enlargement and division of the optic lobe as well as structural foldings and complexity in the underlying CNS are linked to behavioral adaptation (diurnal versus nocturnal; social versus solitary) and ecological niche (reef versus deep sea), but phylogeny may play a part also. The difference between solitary and social life is mirrored within the brain including the formation of multiple compartments (gyri) in the vertical lobe, which is likened to the vertebrate cortex. These findings continue the case for convergence between cephalopod and vertebrate brain structure and function. Notably, within the current push toward comparisons of cognitive abilities, often with unashamed anthropomorphism at their root, these findings provide a firm grounding from which to work.
... In the Seto Inland Sea, one of the main fishing grounds of this species in Japan, the spawning occurs during spring and a female spawns 100−200 eggs. The size of A. fangsiao eggs is relatively large (7−10 mm in length) among benthic octopuses, and the duration from spawning to hatching lasts 50−60 days (Jiang et al. 2020a(Jiang et al. , 2020bYoshikawa et al. 2016). The offspring commences benthic life immediately after hatching, and the lifespan is about one year (Kitajima and Hayashida 1985;Segawa and Nomoto 2002;Yamauchi and Takeda 1964;Yoshikawa et al. 2016 (Abe et al. 1997;Sauer et al. 2020). ...
For benthic octopuses, shelter utilisation is a common behaviour to defend their vulnerable soft bodies against predators. Furthermore, most species of octopus exhibit egg-care behaviour, and the brooding females often attach their egg masses on the inside of the shelters to defend their eggs securely. The type of shelter is therefore a matter of concern for brooding females, affecting their reproductive success. This study aimed to investigate the shelter preference and utilisation behaviour of the small benthic octopus Amphioctopus fangsiao. Five types of shelters, including empty shells of bivalve Saxidomus purpurata and gastropod Rapana venosa, and different-sized artificial pottery pots, were introduced into the aquaria where eight female octopuses were individually reared. The types of shelters utilised by the females were recorded twice a day until they started spawning (observation period, 12-28 days). Six females with a body weight (BW) ranging from 68 to 125 g utilised the gastropod shells most frequently, and four females attached their eggs to the inside of the shells. Characteristic shell-wearing behaviour like that of live gastropods was observed for these females. Meanwhile, large two females with 135 and 182 g BW selected the largest artificial pot for spawning, suggesting a body size-dependent shelter preference.
