: A new species of box jellyfish, Carybdea wayamba sp. nov. is described here based on forty specimens collected from the south and northeast coasts of Sri Lanka, with the type location being Bonavista Reef, Galle Bay. This species is classified in the genus Carybdea due to the possession of a typical heart-shaped rhopaliar niche ostia with only one upper scale and epaulette-shaped gastric phacellae in the four corners of the stomach. This new species can be distinguished from other valid members of the genus Carybdea by the combination of the structure of the two velarial canal roots per octant with one broadly bi-forked velarial canal with narrow, lateral lobations on each root, and other morphological characters such as having typical knee-shaped pedalial canal bends without any appendages, and epaulette-shaped gastric phacellae with single-rooted, brush-shaped, multiple (three to five) short-stemmed, dendritically branched (both short and long branches) gastric filaments. This is the first novel cubomedusa described from Sri Lankan waters; and the first Carybdea species described with material from the North Indian Ocean.
{"title":"A new species of box jellyfish, Carybdea wayamba sp. nov. (Cnidaria: Scyphozoa: Cubomedusae: Carybdeidae) from Sri Lanka","authors":"K. Karunarathne, M. Croos","doi":"10.3800/pbr.15.317","DOIUrl":"https://doi.org/10.3800/pbr.15.317","url":null,"abstract":": A new species of box jellyfish, Carybdea wayamba sp. nov. is described here based on forty specimens collected from the south and northeast coasts of Sri Lanka, with the type location being Bonavista Reef, Galle Bay. This species is classified in the genus Carybdea due to the possession of a typical heart-shaped rhopaliar niche ostia with only one upper scale and epaulette-shaped gastric phacellae in the four corners of the stomach. This new species can be distinguished from other valid members of the genus Carybdea by the combination of the structure of the two velarial canal roots per octant with one broadly bi-forked velarial canal with narrow, lateral lobations on each root, and other morphological characters such as having typical knee-shaped pedalial canal bends without any appendages, and epaulette-shaped gastric phacellae with single-rooted, brush-shaped, multiple (three to five) short-stemmed, dendritically branched (both short and long branches) gastric filaments. This is the first novel cubomedusa described from Sri Lankan waters; and the first Carybdea species described with material from the North Indian Ocean.","PeriodicalId":56054,"journal":{"name":"Plankton & Benthos Research","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44538292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
On April 10, 2015, three individuals of an undescribed species of ctenophore were observed moving just above the seafloor in the Arecibo Amphitheater inside the Guajataca Canyon, north-northwest of Puerto Rico at a depth of approximately 3,900 m. The ctenophore is distinctive; having two prominent tentacle arms, a body that is rectangular when observed laterally along the tentacular plane, and rounded when observed laterally along the stomodeal plane. The tentacle arms each give rise to an extensible tentacle bearing short tentilla of uniform length and distribution. One ctenophore appeared to be anchored to the seafloor by its two long flexible tentacles, as well as by two filaments exiting its oral end. The overall form of the ctenophore suggests classification within the problematic, non-monophyletic order Cydippida, but the robust tentacle arms are more reminiscent of benthic species of Platyctenida, particularly those of families Lyroctenidae and Ctenoplanidae. Whereas most platyctenid ctenophores do not possess ctene rows in their adult forms, features that are possessed by the new species described herein, species of Ctenoplanidae retain comb rows as adults and are capable of limited swimming. The species described herein is easily distinguishable from all other known species of Ctenophora and may trace its origin to a lineage diverging near the origin of Platyctenida.
{"title":"Duobrachium sparksae (incertae sedis Ctenophora Tentaculata Cydippida): A new genus and species of benthopelagic ctenophore seen at 3,910 m depth off the coast of Puerto Rico","authors":"M. Ford, N. Bezio, A. Collins","doi":"10.3800/pbr.15.296","DOIUrl":"https://doi.org/10.3800/pbr.15.296","url":null,"abstract":"On April 10, 2015, three individuals of an undescribed species of ctenophore were observed moving just above the seafloor in the Arecibo Amphitheater inside the Guajataca Canyon, north-northwest of Puerto Rico at a depth of approximately 3,900 m. The ctenophore is distinctive; having two prominent tentacle arms, a body that is rectangular when observed laterally along the tentacular plane, and rounded when observed laterally along the stomodeal plane. The tentacle arms each give rise to an extensible tentacle bearing short tentilla of uniform length and distribution. One ctenophore appeared to be anchored to the seafloor by its two long flexible tentacles, as well as by two filaments exiting its oral end. The overall form of the ctenophore suggests classification within the problematic, non-monophyletic order Cydippida, but the robust tentacle arms are more reminiscent of benthic species of Platyctenida, particularly those of families Lyroctenidae and Ctenoplanidae. Whereas most platyctenid ctenophores do not possess ctene rows in their adult forms, features that are possessed by the new species described herein, species of Ctenoplanidae retain comb rows as adults and are capable of limited swimming. The species described herein is easily distinguishable from all other known species of Ctenophora and may trace its origin to a lineage diverging near the origin of Platyctenida.","PeriodicalId":56054,"journal":{"name":"Plankton & Benthos Research","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47962120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: The order Coronatae is a unique group, with the following characters distinguishing them from other scy-phozoans: a coronal furrow, a coronate pedalium, and oocytes that develop without accessory pigments. Coronatae polyps are enclosed in chitinous tubes and produce multiple ephyrae via polydisk strobilation. So far, eleven described species of Coronatae have been reported in Japanese waters: Atolla wyvillei , Atolla vanhoeffeni , Atolla russelli , Atorella vanhoeffeni , Atorella japonica , Nausithoe punctata , Palephyra pelagica , Periphylla periphylla , Periphyllopsis braueri , Stephanoscyphistoma corniformis and Nausithoe racemosa . The present study reports detailed observations of the mor-phology of one species newly recorded in Japan: Linuche draco . Development from ephyra to mature medusa was observed and recorded. Additional investigations are needed to understand the diversity of the order Coronatae in Japan.
{"title":"New record of Linuche draco (Scyphozoa, Coronatae, Linuchidae) from Japan","authors":"S. Toshino","doi":"10.3800/pbr.15.327","DOIUrl":"https://doi.org/10.3800/pbr.15.327","url":null,"abstract":": The order Coronatae is a unique group, with the following characters distinguishing them from other scy-phozoans: a coronal furrow, a coronate pedalium, and oocytes that develop without accessory pigments. Coronatae polyps are enclosed in chitinous tubes and produce multiple ephyrae via polydisk strobilation. So far, eleven described species of Coronatae have been reported in Japanese waters: Atolla wyvillei , Atolla vanhoeffeni , Atolla russelli , Atorella vanhoeffeni , Atorella japonica , Nausithoe punctata , Palephyra pelagica , Periphylla periphylla , Periphyllopsis braueri , Stephanoscyphistoma corniformis and Nausithoe racemosa . The present study reports detailed observations of the mor-phology of one species newly recorded in Japan: Linuche draco . Development from ephyra to mature medusa was observed and recorded. Additional investigations are needed to understand the diversity of the order Coronatae in Japan.","PeriodicalId":56054,"journal":{"name":"Plankton & Benthos Research","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48875654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A new Japanese record of the Holarctic clam shrimp Lynceus brachyurus is presented with key morphological characteristics and habitat information. The rostrum, clasper, telson, and lamina abdominalis of this insular record are similar to those of the common form of L. brachyurus in continental populations, and our specimens fall within the previously reported species variability.
{"title":"A new record of Lynceus brachyurus Müller, 1776 (Laevicaudata: Lynceidae) from the Shiretoko Peninsula, Northeast Japan","authors":"Norihito Takahashi","doi":"10.3800/pbr.15.334","DOIUrl":"https://doi.org/10.3800/pbr.15.334","url":null,"abstract":"A new Japanese record of the Holarctic clam shrimp Lynceus brachyurus is presented with key morphological characteristics and habitat information. The rostrum, clasper, telson, and lamina abdominalis of this insular record are similar to those of the common form of L. brachyurus in continental populations, and our specimens fall within the previously reported species variability.","PeriodicalId":56054,"journal":{"name":"Plankton & Benthos Research","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42546237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Takehiro Matsumoto, Hiroaki Arakawa, T. Murakami, S. Yanai
Two semi-terrestrial crab species, Chiromantes haematocheir and Chiromantes dehaani, are closely related and have a sympatric distribution. The ecological characteristics of these species, including habitat and behavior during the adult stage, have been investigated. However, the larval stage remains poorly understood because it is difficult to identify larvae morphologically. Our study objectives are to clarify the settlement patterns involved in recruitment of the two species of megalopae using genetic analysis and the effects of ecological factors on settlement, including 1) seasonal changes, 2) spatial variations (dominated by conspecific or heterospecific adults), and 3) tidal effects. The Chiromantes megalopae were collected in the lower reach of the Sai River during spring and neap tides from August to November 2017. Megalopa larvae were collected from three areas: one dominated by C. haematocheir adults, one dominated by C. dehaani adults, and a revetment area. Both species of megalopae showed seasonal and spatial variations in settlement, which also differed with tidal fluctuations. Chiromantes dehaani megalopae settled from midAugust to early October and C. haematocheir megalopae settled from early September to early November. Chiromantes haematocheir megalopae preferentially settled in the area dominated by conspecific adults over the area dominated by C. dehaani and the revetment area, while no difference in the settlement of C. dehaani megalopae was observed among areas. Chiromantes haematocheir megalopae returned on the spring tide; however, C. dehaani megalopae showed no tidal pattern.
{"title":"Settlement patterns of two sesarmid megalopae in the Sai River Estuary, Ishikawa Prefecture, Japan","authors":"Takehiro Matsumoto, Hiroaki Arakawa, T. Murakami, S. Yanai","doi":"10.3800/pbr.15.306","DOIUrl":"https://doi.org/10.3800/pbr.15.306","url":null,"abstract":"Two semi-terrestrial crab species, Chiromantes haematocheir and Chiromantes dehaani, are closely related and have a sympatric distribution. The ecological characteristics of these species, including habitat and behavior during the adult stage, have been investigated. However, the larval stage remains poorly understood because it is difficult to identify larvae morphologically. Our study objectives are to clarify the settlement patterns involved in recruitment of the two species of megalopae using genetic analysis and the effects of ecological factors on settlement, including 1) seasonal changes, 2) spatial variations (dominated by conspecific or heterospecific adults), and 3) tidal effects. The Chiromantes megalopae were collected in the lower reach of the Sai River during spring and neap tides from August to November 2017. Megalopa larvae were collected from three areas: one dominated by C. haematocheir adults, one dominated by C. dehaani adults, and a revetment area. Both species of megalopae showed seasonal and spatial variations in settlement, which also differed with tidal fluctuations. Chiromantes dehaani megalopae settled from midAugust to early October and C. haematocheir megalopae settled from early September to early November. Chiromantes haematocheir megalopae preferentially settled in the area dominated by conspecific adults over the area dominated by C. dehaani and the revetment area, while no difference in the settlement of C. dehaani megalopae was observed among areas. Chiromantes haematocheir megalopae returned on the spring tide; however, C. dehaani megalopae showed no tidal pattern.","PeriodicalId":56054,"journal":{"name":"Plankton & Benthos Research","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42105226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: Sea pens are ecologically important habitats for associated marine organisms, serving as ecosystem engi neers in sandy or muddy seafloor environments. In such areas, sea pens can form habitats with high population densi ties known as “ sea pen fields ” . However, the presence and importance of sea pen fields have not been well studied in shallow waters in East Asia. Here, we report a sea pen field of Virgularia sp. aff. gustaviana in the shallow waters of Ushibuka Marine Park, in the Amakusa Islands of southern Japan. The average colony numbers of the field across all depths (7–20 m) was 10.3 colonies/m 2 (live colonies) to 13.6 colonies/m 2 (all: live + dead colonies + holes), and the area of the sea pen field was at least ∼ 50,000 m 2 . At a depth of 15 m, the substratum consisted of sand and fallen leaves of terrestrial origin, and the highest sea pen density was observed (averages = 17.2 live colonies/m 2 , = 25.8 total (live + dead + holes) colonies/m 2 ). At a depth of 20 m, the substratum consisted of broken shells and rocks and had the lowest density (live colonies: average = 0.8 colonies/m 2 , all: average = 1.0 colonies/m 2 ). There were significant differ ences in colony number of Virgularia sp. aff. gustaviana between the “ sand ” , “ sand + leaves ” , and “ broken shells/rocks ” substrates. We hypothesize that the strength of the water currents caused by local geographic features and tidal move ments produce suitable sedimentation and habitat for this species of sea pen. Therefore, we suggest that preserving the natural coastline is crucial to protect this and other sea pen fields in shallow waters and their benthic marine communi ties.
：海堤是相关海洋生物的重要生态栖息地，在沙质或泥泞的海底环境中起着生态系统工程师的作用。在这些地区，海堤可以形成种群密度高的栖息地，被称为“海堤场”。然而，东亚浅水区海洋围栏的存在和重要性尚未得到很好的研究。在这里，我们报道了一个Virgularia sp.affe的海洋围栏。在日本南部的Amakusa群岛的Ushibuka海洋公园的浅水中的阵风。所有深度（7–20 m）的场平均菌落数为10.3个菌落/m 2（活菌落）至13.6个菌落/m2（全部：活菌落+死菌落+洞），海堤场面积至少为～50000 m 2。在15m深度处，下层由沙和陆生落叶组成，观察到最高的海堤密度（平均=17.2个活菌落/m2，=25.8个总（活+死+洞）菌落/m2）。在20 m深度处，基质由破碎的贝壳和岩石组成，密度最低（活菌落：平均=0.8个菌落/m 2，全部：平均=1.0个菌落/m2）。Virgularia sp.的菌落数量存在显著差异。“沙子”、“沙子+树叶”和“破碎的贝壳/岩石”基质之间的古斯塔维亚纳。我们假设，由当地地理特征和潮汐移动引起的水流强度为该海堤物种产生了合适的沉积和栖息地。因此，我们建议，保护自然海岸线对于保护该海域和其他浅水海域及其底栖海洋群落至关重要。
{"title":"A sea pen field in shallow water in the Amakusa Islands, southern Japan","authors":"Yuka Kushida, H. Kise, C. McFadden, J. Reimer","doi":"10.3800/pbr.15.259","DOIUrl":"https://doi.org/10.3800/pbr.15.259","url":null,"abstract":": Sea pens are ecologically important habitats for associated marine organisms, serving as ecosystem engi neers in sandy or muddy seafloor environments. In such areas, sea pens can form habitats with high population densi ties known as “ sea pen fields ” . However, the presence and importance of sea pen fields have not been well studied in shallow waters in East Asia. Here, we report a sea pen field of Virgularia sp. aff. gustaviana in the shallow waters of Ushibuka Marine Park, in the Amakusa Islands of southern Japan. The average colony numbers of the field across all depths (7–20 m) was 10.3 colonies/m 2 (live colonies) to 13.6 colonies/m 2 (all: live + dead colonies + holes), and the area of the sea pen field was at least ∼ 50,000 m 2 . At a depth of 15 m, the substratum consisted of sand and fallen leaves of terrestrial origin, and the highest sea pen density was observed (averages = 17.2 live colonies/m 2 , = 25.8 total (live + dead + holes) colonies/m 2 ). At a depth of 20 m, the substratum consisted of broken shells and rocks and had the lowest density (live colonies: average = 0.8 colonies/m 2 , all: average = 1.0 colonies/m 2 ). There were significant differ ences in colony number of Virgularia sp. aff. gustaviana between the “ sand ” , “ sand + leaves ” , and “ broken shells/rocks ” substrates. We hypothesize that the strength of the water currents caused by local geographic features and tidal move ments produce suitable sedimentation and habitat for this species of sea pen. Therefore, we suggest that preserving the natural coastline is crucial to protect this and other sea pen fields in shallow waters and their benthic marine communi ties.","PeriodicalId":56054,"journal":{"name":"Plankton & Benthos Research","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41509312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: Mysid specimens collected at Lombok Island, Indonesia were examined and assessed taxonomically. These specimens share morphological characteristics with species of the subgenus Javanisomysis (genus Anisomysis ). They are separable from the other four known species of the subgenus by the structure of the fourth male pleopod, and the condition and pattern of sub-segmentation in the third to eighth thoracopodal carpopropodi of both sexes. The male pleopod is long and reaches the posterior end of the sixth abdominal somite, excluding the apical barbed setae, and the first segment of the pleopod is broader in the proximal one-fourth to one-third. The third to eighth thoracopodal carpopropodi are divided distally into two segments. The population from Lombok Island thus is considered an undescribed species of the subgenus. On the basis of characteristics of the fourth male pleopod, a key to species of the subgenus is provided.
{"title":"A new species in the subgenus Javanisomysis in the genus Anisomysis (Crustacea: Mysida: Mysidae) for specimens collected from Lombok Island, Indonesia","authors":"S. Sawamoto, Y. Hanamura, R. Mantiri, S. Ohtsuka","doi":"10.3800/pbr.15.238","DOIUrl":"https://doi.org/10.3800/pbr.15.238","url":null,"abstract":": Mysid specimens collected at Lombok Island, Indonesia were examined and assessed taxonomically. These specimens share morphological characteristics with species of the subgenus Javanisomysis (genus Anisomysis ). They are separable from the other four known species of the subgenus by the structure of the fourth male pleopod, and the condition and pattern of sub-segmentation in the third to eighth thoracopodal carpopropodi of both sexes. The male pleopod is long and reaches the posterior end of the sixth abdominal somite, excluding the apical barbed setae, and the first segment of the pleopod is broader in the proximal one-fourth to one-third. The third to eighth thoracopodal carpopropodi are divided distally into two segments. The population from Lombok Island thus is considered an undescribed species of the subgenus. On the basis of characteristics of the fourth male pleopod, a key to species of the subgenus is provided.","PeriodicalId":56054,"journal":{"name":"Plankton & Benthos Research","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48149750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: Burrows produced by marine invertebrates often harbor other small commensal invertebrates. The mud shrimp Upogebia is known to coexist with the myid bivalve Cryptomya in a burrow produced by the shrimp. Both species are filter-feeders, and thus interspecific competition or trophic niche segregation may occur in the burrow. Samples for carbon and nitrogen stable isotope analysis were collected from a tidal flat near the tidal inlet of Akkeshi Lake, Hokkaido, northern Japan in April 2013. In addition, stratified benthos sampling was conducted on the tidal flat in August 2018, to clarify the interspecific relationship between U. major and C. busoensis in the burrow. The stratified benthos sampling showed the vertical distribution of these species, and indicated that both species filter water from the same part of the burrow for feeding. The stable carbon and nitrogen isotope analysis showed that important food sources for both U. major and C. busoensis are marine phytoplankton and microphytobenthos. In addition, C. busoensis is likely to consume terrestrial organic matter whereas U. major is unable to utilize it. The partial trophic segregation between the species increases the potential benthic filtering because it allows the Upogebia burrow complex to con sume a wide variety of organic matter, and it might reduce interspecific competition between the filter-feeding host and its commensal species. These results demonstrate how ecologically similar macrobenthos can coexist in a burrow.
{"title":"Trophic segregation in a burrow: the stable carbon and nitrogen isotope ratios of the burrowing shrimp Upogebia major and its commensal bivalve Cryptomya busoensis","authors":"K. Seike, R. Goto","doi":"10.3800/pbr.15.220","DOIUrl":"https://doi.org/10.3800/pbr.15.220","url":null,"abstract":": Burrows produced by marine invertebrates often harbor other small commensal invertebrates. The mud shrimp Upogebia is known to coexist with the myid bivalve Cryptomya in a burrow produced by the shrimp. Both species are filter-feeders, and thus interspecific competition or trophic niche segregation may occur in the burrow. Samples for carbon and nitrogen stable isotope analysis were collected from a tidal flat near the tidal inlet of Akkeshi Lake, Hokkaido, northern Japan in April 2013. In addition, stratified benthos sampling was conducted on the tidal flat in August 2018, to clarify the interspecific relationship between U. major and C. busoensis in the burrow. The stratified benthos sampling showed the vertical distribution of these species, and indicated that both species filter water from the same part of the burrow for feeding. The stable carbon and nitrogen isotope analysis showed that important food sources for both U. major and C. busoensis are marine phytoplankton and microphytobenthos. In addition, C. busoensis is likely to consume terrestrial organic matter whereas U. major is unable to utilize it. The partial trophic segregation between the species increases the potential benthic filtering because it allows the Upogebia burrow complex to con sume a wide variety of organic matter, and it might reduce interspecific competition between the filter-feeding host and its commensal species. These results demonstrate how ecologically similar macrobenthos can coexist in a burrow.","PeriodicalId":56054,"journal":{"name":"Plankton & Benthos Research","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45657429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: This paper describes “ inverse rapping ” as a characteristic mating behavior in Pagurus nigrofascia . The behavior involves one hermit crab pulling another crab ʼ s shell towards itself causing the shells to hit against each other. This is the first evidence that males perform inverse rapping as a mating behavior in a Pagurus species. Two experi-ments were conducted to describe the inverse rapping in detail and to discuss its function. In Experiment A, we clarified when (mating season or non-mating season) and to whom (males or females) males displayed this behavior. A focal male that had not been guarding in the field was placed together with another crab and their interaction was observed, especially inverse rapping. Males showed inverse rapping mainly with a female that was close to copulation in the mating season, especially when the male guarded the female. In Experiment B, we examined the female ʼ s response to male inverse rapping and tested the effect of the presence of a neighboring conspecific on the occurrence of the behavior. Most females reduced struggling and/or withdrew into their shells in response to male inverse rapping. The presence of neighboring crabs did not affect inverse rapping. Our findings suggest that inverse rapping is a mating behavior in P. nigrofascia , and that inverse rapping may benefit males in the initiation and/or continuation of precopulatory guarding because it can help to restrain struggling females. This behavior has not been observed in other sympatric Pagurus species and appears to be a characteristic mating behavior of P. nigrofascia .
{"title":"Males display “inverse rapping” as a mating behavior to receptive females in the hermit crab Pagurus nigrofascia","authors":"Yuina Kido, S. Wada","doi":"10.3800/pbr.15.279","DOIUrl":"https://doi.org/10.3800/pbr.15.279","url":null,"abstract":": This paper describes “ inverse rapping ” as a characteristic mating behavior in Pagurus nigrofascia . The behavior involves one hermit crab pulling another crab ʼ s shell towards itself causing the shells to hit against each other. This is the first evidence that males perform inverse rapping as a mating behavior in a Pagurus species. Two experi-ments were conducted to describe the inverse rapping in detail and to discuss its function. In Experiment A, we clarified when (mating season or non-mating season) and to whom (males or females) males displayed this behavior. A focal male that had not been guarding in the field was placed together with another crab and their interaction was observed, especially inverse rapping. Males showed inverse rapping mainly with a female that was close to copulation in the mating season, especially when the male guarded the female. In Experiment B, we examined the female ʼ s response to male inverse rapping and tested the effect of the presence of a neighboring conspecific on the occurrence of the behavior. Most females reduced struggling and/or withdrew into their shells in response to male inverse rapping. The presence of neighboring crabs did not affect inverse rapping. Our findings suggest that inverse rapping is a mating behavior in P. nigrofascia , and that inverse rapping may benefit males in the initiation and/or continuation of precopulatory guarding because it can help to restrain struggling females. This behavior has not been observed in other sympatric Pagurus species and appears to be a characteristic mating behavior of P. nigrofascia .","PeriodicalId":56054,"journal":{"name":"Plankton & Benthos Research","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48665659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: Mesochaetopterus is a bioluminescent polychaete that belongs to the family Chaetopteridae. It secrets a blue luminescent mucus as a response to mechanical stimulation similar to the species in Chaetopterus (Chae -topteridae). However, unlike Chaetopterus , the biochemical properties of Mesochaetopterus bioluminescence are largely unexplored. In this study, we examined the basic biochemical properties of the bioluminescence seen in Mesochaetopterus japonicus and compared them to those seen in Chaetopterus . The comparison revealed that similar blue luminescence peaked at approximately 460 nm were induced by the addition of Fe 2 + and H 2 O 2 , suggesting that bioluminescence in M. japonicus and Chaetopterus has similar basic biochemical properties. On the other hand, the gel filtration analyses showed that the elution volumes of active proteins were different between Mesochaetopterus and Chaetopterus . The molecular weights of these proteins were estimated to be 150 kDa and 90 kDa (approximately) for Mesochaetopterus and Chaetopterus , respectively.
{"title":"Bioluminescent properties of Mesochaetopterus japonicus (Polychaeta: Chaetopteridae) with comparison to Chaetopterus","authors":"Ikuhiko Kin, Y. Oba","doi":"10.3800/pbr.15.228","DOIUrl":"https://doi.org/10.3800/pbr.15.228","url":null,"abstract":": Mesochaetopterus is a bioluminescent polychaete that belongs to the family Chaetopteridae. It secrets a blue luminescent mucus as a response to mechanical stimulation similar to the species in Chaetopterus (Chae -topteridae). However, unlike Chaetopterus , the biochemical properties of Mesochaetopterus bioluminescence are largely unexplored. In this study, we examined the basic biochemical properties of the bioluminescence seen in Mesochaetopterus japonicus and compared them to those seen in Chaetopterus . The comparison revealed that similar blue luminescence peaked at approximately 460 nm were induced by the addition of Fe 2 + and H 2 O 2 , suggesting that bioluminescence in M. japonicus and Chaetopterus has similar basic biochemical properties. On the other hand, the gel filtration analyses showed that the elution volumes of active proteins were different between Mesochaetopterus and Chaetopterus . The molecular weights of these proteins were estimated to be 150 kDa and 90 kDa (approximately) for Mesochaetopterus and Chaetopterus , respectively.","PeriodicalId":56054,"journal":{"name":"Plankton & Benthos Research","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45480377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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