There have been several records in the last 60 years for East Antarctica for Milnesium tardigradum Doyère, 1840 sensu lato, now considered a species complex. During the 56th Japanese Antarctic Research Expedition summer operation (2014-2015), a new tardigrade species in the genus Milnesium Doyère, 1840 was found in an ice-free Innhovde area along Lützow-Holm Bay, Dronning Maud Land, East Antarctica. The new species has aberrant claws with four to seven points on each secondary claw branch, which distinguishes it from other Milnesium species. A male specimen was found in the population and evidence showed that an isolated adult female moulted twice without oviposition. This strongly suggested bisexual reproduction for this population. The new species, Milnesium rastrum sp. nov., is described with its phylogenetic position and a discussion on the reproductive strategies for the harsh environments.
在过去的60年里,在东南极洲有一些关于千年缓步虫(milium tardigradum doy, 1840年)的记录,现在被认为是一个物种复合体。在第56次日本南极科考夏季行动(2014-2015)期间,在南极洲东部Dronning Maud Land l zow- holm湾的无冰inhovde地区发现了一种新的Milnesium doy属缓步动物,1840。这个新物种有异常的爪子,每个次级爪子分支上有4到7个尖,这使它与其他千禧年物种区别开来。在种群中发现了一只雄性标本,有证据表明,一只孤立的成年雌性在没有产卵的情况下换了两次毛。这有力地表明,这个群体中存在双性恋生殖。本文描述了新发现的物种——黄花千万年(Milnesium rastrum sp. nov.)的系统发育位置,并对其在恶劣环境下的繁殖策略进行了讨论。
{"title":"A New Species of Bisexual <i>Milnesium</i> (Eutardigrada: Apochela) Having Aberrant Claws from Innhovde, Dronning Maud Land, East Antarctica.","authors":"Atsushi C Suzuki, Kenta Sugiura, Megumu Tsujimoto, Ryosuke Nakai, Sandra J McInnes, Hiroshi Kagoshima, Satoshi Imura","doi":"10.2108/zs220085","DOIUrl":"https://doi.org/10.2108/zs220085","url":null,"abstract":"<p><p>There have been several records in the last 60 years for East Antarctica for <i>Milnesium tardigradum</i> Doyère, 1840 sensu lato, now considered a species complex. During the 56th Japanese Antarctic Research Expedition summer operation (2014-2015), a new tardigrade species in the genus <i>Milnesium</i> Doyère, 1840 was found in an ice-free Innhovde area along Lützow-Holm Bay, Dronning Maud Land, East Antarctica. The new species has aberrant claws with four to seven points on each secondary claw branch, which distinguishes it from other <i>Milnesium</i> species. A male specimen was found in the population and evidence showed that an isolated adult female moulted twice without oviposition. This strongly suggested bisexual reproduction for this population. The new species, <i>Milnesium rastrum</i> sp. nov., is described with its phylogenetic position and a discussion on the reproductive strategies for the harsh environments.</p>","PeriodicalId":24040,"journal":{"name":"Zoological Science","volume":"40 3","pages":"246-261"},"PeriodicalIF":0.9,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9615202","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}
Mitochondrial genomes are used widely for the molecular phylogenetic analysis of animals. Although phylogenetic analyses based on the mitogenomes of brachyurans often yield well-resolved phylogenies, most interfamilial phylogenetic relationships in Thoracotremata remain unclear. We determined nine new mitogenomes of Thoracotremata, including mitogenomes of Camptandriidae (Deiratonotus japonicus), Dotillidae (Ilyoplax integra, Ilyoplax pusilla, and Tmethypocoelis choreutes), Macrophthalmidae (Ilyograpsus nodulosus), Pinnotheridae (Arcotheres sp. and Indopinnixa haematosticta), Plagusiidae (Guinusia dentipes), and Percnidae (Percnon planissimum). Interestingly, Percnon planissimum (Percnidae) was found to possess ≥ 19 repeated sequences in the control region. The gene orders of Il. nodulosus, Arcotheres sp., and In. haematosticta were revealed to be unique among thoracotreme crabs. Although the results of Bayesian and maximum likelihood (ML) phylogenetic analyses of three datasets were incongruent, highly supported clades (PP ≥ 0.99 or BS ≥ 99%) were not contradictory among the analyses. All analyses suggested the paraphyly of Grapsoidea and Ocypodoidea, corroborating the findings of previous studies based on molecular phylogenies of thoracotreme crabs. The phylogenetic positions of symbiotic thoracotreme crabs, Pinnotheridae and Cryptochiridae, were highly supported (Pinnotheridae + Ocypodidae and Cryptochiridae + Grapsidae, respectively) for the Bayesian analyses but not for the ML analyses. Analyses of more thoracotreme species' mitogenome sequences in additional studies will further strengthen the framework for thoracotreme evolution.
{"title":"Molecular Phylogeny of Thoracotreme Crabs Including Nine Newly Determined Mitochondrial Genomes.","authors":"Genki Kobayashi, Hajime Itoh, Nobuyoshi Nakajima","doi":"10.2108/zs220063","DOIUrl":"https://doi.org/10.2108/zs220063","url":null,"abstract":"<p><p>Mitochondrial genomes are used widely for the molecular phylogenetic analysis of animals. Although phylogenetic analyses based on the mitogenomes of brachyurans often yield well-resolved phylogenies, most interfamilial phylogenetic relationships in Thoracotremata remain unclear. We determined nine new mitogenomes of Thoracotremata, including mitogenomes of Camptandriidae (<i>Deiratonotus japonicus</i>), Dotillidae (<i>Ilyoplax integr</i>a, <i>Ilyoplax pusilla</i>, and <i>Tmethypocoelis choreutes</i>), Macrophthalmidae (<i>Ilyograpsus nodulosus</i>), Pinnotheridae (<i>Arcotheres</i> sp. and <i>Indopinnixa haematosticta</i>), Plagusiidae (<i>Guinusia dentipes</i>), and Percnidae (<i>Percnon planissimum</i>). Interestingly, <i>Percnon planissimum</i> (Percnidae) was found to possess ≥ 19 repeated sequences in the control region. The gene orders of <i>Il. nodulosus</i>, <i>Arcotheres</i> sp., and <i>In. haematosticta</i> were revealed to be unique among thoracotreme crabs. Although the results of Bayesian and maximum likelihood (ML) phylogenetic analyses of three datasets were incongruent, highly supported clades (<i>PP</i> ≥ 0.99 or <i>BS</i> ≥ 99%) were not contradictory among the analyses. All analyses suggested the paraphyly of Grapsoidea and Ocypodoidea, corroborating the findings of previous studies based on molecular phylogenies of thoracotreme crabs. The phylogenetic positions of symbiotic thoracotreme crabs, Pinnotheridae and Cryptochiridae, were highly supported (Pinnotheridae + Ocypodidae and Cryptochiridae + Grapsidae, respectively) for the Bayesian analyses but not for the ML analyses. Analyses of more thoracotreme species' mitogenome sequences in additional studies will further strengthen the framework for thoracotreme evolution.</p>","PeriodicalId":24040,"journal":{"name":"Zoological Science","volume":"40 3","pages":"224-234"},"PeriodicalIF":0.9,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9561950","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}
Frequent coral bleaching has drawn attention to the mechanisms of coral dinoflagellate endosymbiosis. Owing to the difficulty of rearing corals in the laboratory, model symbiosis systems are desired. The sea anemone Exaiptasia diaphana, hosting clade B1 of the genus Breviolum, has long been studied as a model system; however, a single species is insufficient for comparative studies and thus provides only limited resources for symbiosis research, especially regarding the specificity of host-symbiont associations. We established a clonal strain of the sea anemone Anthopleura atodai, whose symbiont was identified as a novel subclade of Symbiodinium (clade A) using a novel feeding method. We also developed a method to efficiently bleach various sea anemone species using a quinoclamine-based herbicide. Bleached A. atodai polyps were vital and able to reproduce asexually, exhibiting no signs of harmful effects of the drug treatment. Pilot studies have suggested that host-symbiont specificity is influenced by multiple steps differently in A. atodai and E. diaphana. RNAseq analyses of A. atodai showed that multiple NPC2 genes were expressed in the symbiotic state, which have been suggested to function in the transport of sterols from symbionts to host cells. These results reveal the usefulness of A. atodai in comparative studies of cnidarian-algal symbiosis.
{"title":"Establishment of a New Model Sea Anemone for Comparative Studies on Cnidarian-Algal Symbiosis.","authors":"Yukie Mihirogi, Michika Kaneda, Daisuke Yamagishi, Yuu Ishii, Shinichiro Maruyama, Sumika Nakamura, Natsuno Shimoyama, Chihiro Oohori, Masayuki Hatta","doi":"10.2108/zs220099","DOIUrl":"https://doi.org/10.2108/zs220099","url":null,"abstract":"<p><p>Frequent coral bleaching has drawn attention to the mechanisms of coral dinoflagellate endosymbiosis. Owing to the difficulty of rearing corals in the laboratory, model symbiosis systems are desired. The sea anemone <i>Exaiptasia diaphana</i>, hosting clade B1 of the genus <i>Breviolum</i>, has long been studied as a model system; however, a single species is insufficient for comparative studies and thus provides only limited resources for symbiosis research, especially regarding the specificity of host-symbiont associations. We established a clonal strain of the sea anemone <i>Anthopleura atodai</i>, whose symbiont was identified as a novel subclade of <i>Symbiodinium</i> (clade A) using a novel feeding method. We also developed a method to efficiently bleach various sea anemone species using a quinoclamine-based herbicide. Bleached <i>A. atodai</i> polyps were vital and able to reproduce asexually, exhibiting no signs of harmful effects of the drug treatment. Pilot studies have suggested that host-symbiont specificity is influenced by multiple steps differently in <i>A. atodai</i> and <i>E. diaphana</i>. RNAseq analyses of <i>A. atodai</i> showed that multiple <i>NPC2</i> genes were expressed in the symbiotic state, which have been suggested to function in the transport of sterols from symbionts to host cells. These results reveal the usefulness of <i>A. atodai</i> in comparative studies of cnidarian-algal symbiosis.</p>","PeriodicalId":24040,"journal":{"name":"Zoological Science","volume":"40 3","pages":"235-245"},"PeriodicalIF":0.9,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9561948","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}
As a contribution to improving management of the Japanese wild boar (Sus scrofa leucomystax), which has recently expanded its range and is having some negative effects on the ecosystem, we conducted a landscape genetic study using individual-based genetic analysis and multiple landscape elements to elucidate its dispersal patterns in the early stage of its expansion. Microsatellite DNA analysis of Japanese wild boars in the Hokuriku region of Japan revealed the existence of two ancestral genetic clusters, that they had migrated via different pathways, and that they were inadequately admixed. We also inferred the most suitable habitats for Japanese wild boar using MaxEnt and concluded that lower elevation and snowfall may favor the occurrence of wild boar individuals. Landscape genetic analysis indicated regional differences in Japanese wild boar dispersal patterns, according to the spatial heterogeneity of genetic features and landscape elements. On the western side of the study area, where individuals with a high frequency of one of two ancestral clusters were more abundant, significant effects of isolation by distance and resistance due to the above two landscape factors were detected, suggesting unidirectional dispersion influenced by the alpine landscape. In contrast, on the eastern side, there was indication of resistance to dispersal of individuals predominantly possessing another ancestral cluster, suggesting the influence of irregularly arranged suitable habitats due to the complexity of the mountainous terrain. Based on our findings, we conclude that Japanese wild boar dispersal patterns may be influenced by landscape elements, such as alpine mountains.
{"title":"Landscape Genetic Analysis for the Japanese Wild Boar in the Early Expanding Stage in the Hokuriku Region of Japan.","authors":"Yuji Yamazaki, Daisuke Shimizu, Takumi Watanabe","doi":"10.2108/zs220082","DOIUrl":"https://doi.org/10.2108/zs220082","url":null,"abstract":"<p><p>As a contribution to improving management of the Japanese wild boar (<i>Sus scrofa leucomystax</i>), which has recently expanded its range and is having some negative effects on the ecosystem, we conducted a landscape genetic study using individual-based genetic analysis and multiple landscape elements to elucidate its dispersal patterns in the early stage of its expansion. Microsatellite DNA analysis of Japanese wild boars in the Hokuriku region of Japan revealed the existence of two ancestral genetic clusters, that they had migrated via different pathways, and that they were inadequately admixed. We also inferred the most suitable habitats for Japanese wild boar using MaxEnt and concluded that lower elevation and snowfall may favor the occurrence of wild boar individuals. Landscape genetic analysis indicated regional differences in Japanese wild boar dispersal patterns, according to the spatial heterogeneity of genetic features and landscape elements. On the western side of the study area, where individuals with a high frequency of one of two ancestral clusters were more abundant, significant effects of isolation by distance and resistance due to the above two landscape factors were detected, suggesting unidirectional dispersion influenced by the alpine landscape. In contrast, on the eastern side, there was indication of resistance to dispersal of individuals predominantly possessing another ancestral cluster, suggesting the influence of irregularly arranged suitable habitats due to the complexity of the mountainous terrain. Based on our findings, we conclude that Japanese wild boar dispersal patterns may be influenced by landscape elements, such as alpine mountains.</p>","PeriodicalId":24040,"journal":{"name":"Zoological Science","volume":"40 3","pages":"189-196"},"PeriodicalIF":0.9,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9916906","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}
We establish a new interstitial polyclad species, Theama japonica sp. nov., based on specimens collected from coarse-sandy habitats in three Japanese main islands (Hokkaido, Honshu, and Shikoku) along the coasts of the Pacific Ocean and the Sea of Japan. Theama japonica is characterized by i) two pairs of cerebral eyespots and four to six precerebral eyespots; ii) eosinophilic secretion glands distributed in the distal half of the inner ventral part of the prostatic vesicle; iii) a conical penis papilla, bent up dorsally, with a sclerotized inner wall; iv) the prostatic sheath with an inner angular fold on the dorso-distal side; and v) the external cilia longer dorsally than ventrally. Partial sequences of the cytochrome c oxidase subunit I (COI) gene from 20 specimens collected at eight localities along Japanese coasts represented 19 haplotypes. The uncorrected p-distances among these COI haplotypes fell within intraspecific variations observed in other polyclads. A network analysis based on these COI haplotypes suggested a geographically non-cohesive genetic structure of the species, possibly indicating the species' high dispersibility. Molecular phylogenetic analyses based on a concatenated dataset of 18S and 28S rDNA sequences showed T. japonica formed a clade with other Theama species. The resulting tree also indicates that our new species is more closely related to Theama sp. from Colombia than species from Panama and Croatia.
{"title":"<i>Theama japonica</i> sp. nov., an Interstitial Polyclad Flatworm Showing a Wide Distribution along Japanese Coasts.","authors":"Aoi Tsuyuki, Yuki Oya, Naoto Jimi, Natsumi Hookabe, Shinta Fujimoto, Hiroshi Kajihara","doi":"10.2108/zs220105","DOIUrl":"https://doi.org/10.2108/zs220105","url":null,"abstract":"<p><p>We establish a new interstitial polyclad species, <i>Theama japonica</i> sp. nov., based on specimens collected from coarse-sandy habitats in three Japanese main islands (Hokkaido, Honshu, and Shikoku) along the coasts of the Pacific Ocean and the Sea of Japan. <i>Theama japonica</i> is characterized by <i>i</i>) two pairs of cerebral eyespots and four to six precerebral eyespots; <i>ii</i>) eosinophilic secretion glands distributed in the distal half of the inner ventral part of the prostatic vesicle; <i>iii</i>) a conical penis papilla, bent up dorsally, with a sclerotized inner wall; <i>iv</i>) the prostatic sheath with an inner angular fold on the dorso-distal side; and <i>v</i>) the external cilia longer dorsally than ventrally. Partial sequences of the cytochrome <i>c</i> oxidase subunit I (COI) gene from 20 specimens collected at eight localities along Japanese coasts represented 19 haplotypes. The uncorrected <i>p</i>-distances among these COI haplotypes fell within intraspecific variations observed in other polyclads. A network analysis based on these COI haplotypes suggested a geographically non-cohesive genetic structure of the species, possibly indicating the species' high dispersibility. Molecular phylogenetic analyses based on a concatenated dataset of 18S and 28S rDNA sequences showed <i>T. japonica</i> formed a clade with other <i>Theama</i> species. The resulting tree also indicates that our new species is more closely related to <i>Theama</i> sp. from Colombia than species from Panama and Croatia.</p>","PeriodicalId":24040,"journal":{"name":"Zoological Science","volume":"40 3","pages":"262-272"},"PeriodicalIF":0.9,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9561951","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}
Two cytochrome P450 genes homologous to human CYP7A1 and CYP27A1 were cloned from the non-parasitic Japanese lamprey Lethenteron reissneri. Lamprey cyp7a1 mRNA had varied expression levels among individuals: about four orders of magnitude differences in larval liver and nearly three orders of magnitude differences in male adult liver. Overexpressed Cyp7a1 protein tagged with green fluorescent protein (GFP) was localized to the endoplasmic reticulum. Lamprey cyp27a1 mRNA had relatively constant expression levels: within two orders of magnitude differences in larvae and adult liver and intestine. GFP-tagged Cyp27a1 protein was localized to mitochondria. The expression profiles of lamprey cyp7a1 and cyp27a1 genes and the cellular localizations of their products were in good agreement with their counterparts in mammals, where these two P450s catalyze initial hydroxylation reactions of cholesterol in classical and alternative pathways of bile acid synthesis, respectively. The cyp7a1 mRNA levels in adult male liver showed significant negative correlations to both body weight and total length of the animal, implying the involvement of the gene in the production of female-attractive pheromones in sexually matured male livers. The lamprey Cyp7a1 contains a long extension of 116 amino acids between helices D and E of the protein. Possible roles of this extension in regulating the enzymatic activity of lamprey Cyp7a1 are discussed.
{"title":"Cloning and Characterization of <i>Cyp7a1</i> and <i>Cyp27a1</i> Genes from the Non-Parasitic Japanese Lamprey <i>Lethenteron reissneri</i>.","authors":"Mayako Morii, Taku Hebiguchi, Ryo Watanabe, Hiroaki Yoshino, Yoshihiro Mezaki","doi":"10.2108/zs220072","DOIUrl":"https://doi.org/10.2108/zs220072","url":null,"abstract":"<p><p>Two cytochrome P450 genes homologous to human <i>CYP7A1</i> and <i>CYP27A1</i> were cloned from the non-parasitic Japanese lamprey <i>Lethenteron reissneri</i>. Lamprey <i>cyp7a1</i> mRNA had varied expression levels among individuals: about four orders of magnitude differences in larval liver and nearly three orders of magnitude differences in male adult liver. Overexpressed Cyp7a1 protein tagged with green fluorescent protein (GFP) was localized to the endoplasmic reticulum. Lamprey <i>cyp27a1</i> mRNA had relatively constant expression levels: within two orders of magnitude differences in larvae and adult liver and intestine. GFP-tagged Cyp27a1 protein was localized to mitochondria. The expression profiles of lamprey <i>cyp7a1</i> and <i>cyp27a1</i> genes and the cellular localizations of their products were in good agreement with their counterparts in mammals, where these two P450s catalyze initial hydroxylation reactions of cholesterol in classical and alternative pathways of bile acid synthesis, respectively. The <i>cyp7a1</i> mRNA levels in adult male liver showed significant negative correlations to both body weight and total length of the animal, implying the involvement of the gene in the production of female-attractive pheromones in sexually matured male livers. The lamprey Cyp7a1 contains a long extension of 116 amino acids between helices D and E of the protein. Possible roles of this extension in regulating the enzymatic activity of lamprey Cyp7a1 are discussed.</p>","PeriodicalId":24040,"journal":{"name":"Zoological Science","volume":"40 3","pages":"208-218"},"PeriodicalIF":0.9,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9615204","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}
Takumi Onishi, Shimpei Hiruta, Hiroshi Kajihara, Matthew H Dick
The cheilostome bryozoan Cauloramphus magnus is common in the rocky intertidal habitat from southeastern Alaska to northern Japan. We examined its phylogeography by analyzing 576 bp of the mitochondrial COI (cox1) gene sequenced for 298 colonies from 16 localities in northern Japan. A maximum-likelihood phylogeny detected three main clades (A, B, C). Clades A and B occurred throughout the study area but differed in frequency, haplotype diversity, and haplotype distribution; each resolved into three divergent subclades (AI–III, BI–III). Clade A shared none among 15 haplotypes between the Pacific and Sea of Japan sides of Hokkaido. In contrast, Clade B (29 haplotypes) was thrice as common as Clade A among samples, with haplotype B28 common on both sides. Divergent Clade C (nine haplotypes) was detected only at Rumoi. K2P divergences of 12.3–28.3% among Clades A–C suggest these are distinct biological species, a conclusion supported by different inferred evolutionary histories. A bPTP species delimitation analysis indicated nine phylogenetic species among the sequences included in our phylogeny (AI–III, BI–III, C, and one specimen each from Alaska and the Commander Islands), with K2P divergences of 3.9–6.5% among subclades in A or B. Statistical and principal components analyses suggested weak morphological differentiation between Clades A + B and C, although overlapping ranges of measurements preclude identification to clade; these three clades are morphologically cryptic. For taxonomy, we suggest retaining the name C. magnus for lineages within this species complex across its range, followed by a clade designation, if known.
{"title":"The Bryozoan <i>Cauloramphus magnus</i> (Cheilostomata: Calloporidae) in Northern Japan Includes Multiple, Co-occurring Cryptic Species.","authors":"Takumi Onishi, Shimpei Hiruta, Hiroshi Kajihara, Matthew H Dick","doi":"10.2108/zs220093","DOIUrl":"https://doi.org/10.2108/zs220093","url":null,"abstract":"The cheilostome bryozoan Cauloramphus magnus is common in the rocky intertidal habitat from southeastern Alaska to northern Japan. We examined its phylogeography by analyzing 576 bp of the mitochondrial COI (cox1) gene sequenced for 298 colonies from 16 localities in northern Japan. A maximum-likelihood phylogeny detected three main clades (A, B, C). Clades A and B occurred throughout the study area but differed in frequency, haplotype diversity, and haplotype distribution; each resolved into three divergent subclades (AI–III, BI–III). Clade A shared none among 15 haplotypes between the Pacific and Sea of Japan sides of Hokkaido. In contrast, Clade B (29 haplotypes) was thrice as common as Clade A among samples, with haplotype B28 common on both sides. Divergent Clade C (nine haplotypes) was detected only at Rumoi. K2P divergences of 12.3–28.3% among Clades A–C suggest these are distinct biological species, a conclusion supported by different inferred evolutionary histories. A bPTP species delimitation analysis indicated nine phylogenetic species among the sequences included in our phylogeny (AI–III, BI–III, C, and one specimen each from Alaska and the Commander Islands), with K2P divergences of 3.9–6.5% among subclades in A or B. Statistical and principal components analyses suggested weak morphological differentiation between Clades A + B and C, although overlapping ranges of measurements preclude identification to clade; these three clades are morphologically cryptic. For taxonomy, we suggest retaining the name C. magnus for lineages within this species complex across its range, followed by a clade designation, if known.","PeriodicalId":24040,"journal":{"name":"Zoological Science","volume":"40 3","pages":"175-188"},"PeriodicalIF":0.9,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9916907","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}
Tachaea chinensis is a temporary ectoparasite infesting freshwater shrimps and prawns in eastern Asia. This study investigated the host size selection by T. chinensis across common freshwater shrimps under laboratory conditions. A total of 70 isopods were allowed to select between host shrimps of different size and different species in pairwise selection experiments. In treatments involving different sizes of the same host species, T. chinensis tended to select the medium host option in all of the four treatments. Similarly, T. chinensis demonstrated greater preference towards medium host (90%) when provided with mixed host options (medium Palaemon paucidens vs small Neocaridina spp.). However, despite the increase in the infestation proportion on medium Neocaridina spp., the isopod significantly selected the small P. paucidens when provided with a choice between medium Neocaridina spp. and small P. paucidens. In manca stage (1 day after hatch) T. chinensis treatment, the isopods showed no specific preference between large and medium Neocaridina spp. These results suggest that T. chinensis is likely to show size specificity according to the developmental stage, a size specificity that ultimately ensures adequate space for isopods' growth while maintaining a minimum risk of predation.
{"title":"Host Size Selection in the Ectoparasite <i>Tachaea chinensis</i> (Isopoda: Corallanidae) under Laboratory Conditions.","authors":"Al-Wahaibi Mohamed Khalfan, Shotaro Tani, Abdelgayed Younes, Hidetoshi Saito","doi":"10.2108/zs220113","DOIUrl":"https://doi.org/10.2108/zs220113","url":null,"abstract":"<p><p><i>Tachaea chinensis</i> is a temporary ectoparasite infesting freshwater shrimps and prawns in eastern Asia. This study investigated the host size selection by <i>T. chinensis</i> across common freshwater shrimps under laboratory conditions. A total of 70 isopods were allowed to select between host shrimps of different size and different species in pairwise selection experiments. In treatments involving different sizes of the same host species, <i>T. chinensis</i> tended to select the medium host option in all of the four treatments. Similarly, <i>T. chinensis</i> demonstrated greater preference towards medium host (90%) when provided with mixed host options (medium <i>Palaemon paucidens</i> vs small <i>Neocaridina</i> spp.). However, despite the increase in the infestation proportion on medium <i>Neocaridina</i> spp., the isopod significantly selected the small <i>P. paucidens</i> when provided with a choice between medium <i>Neocaridina</i> spp. and small <i>P. paucidens</i>. In manca stage (1 day after hatch) <i>T. chinensis</i> treatment, the isopods showed no specific preference between large and medium <i>Neocaridina</i> spp. These results suggest that <i>T. chinensis</i> is likely to show size specificity according to the developmental stage, a size specificity that ultimately ensures adequate space for isopods' growth while maintaining a minimum risk of predation.</p>","PeriodicalId":24040,"journal":{"name":"Zoological Science","volume":"40 3","pages":"197-202"},"PeriodicalIF":0.9,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9615205","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}
Shumpei Sogawa, Rio Fukushima, Will Sowersby, Satoshi Awata, Kento Kawasaka, Masanori Kohda
Individual recognition is a necessary cognitive ability for the maintenance of stable social relationships. Recent studies have shown that like primates, some fish species can distinguish familiar fish from unfamiliar strangers via face-recognition. However, the taxa of the studied fish species are restricted (within Perciformes) and the visual signal used for the recognition of fish remains unclear. Here, we investigated the visual signal for individual-recognition in males of a sexually dichromatic guppy (Poecilia reticulata, Cyprinodontiformes). Using guppy males, we examined the hypothesis that fish distinguish between familiar individuals and unknown strangers by their faces rather than by body coloration. We randomly presented focal fish with four types of composite photo-models: familiar (familiar-face and familiar-body = F/F), stranger (stranger-face and stranger-body = S/S), familiar face combined with stranger body (F/S) and stranger face combined with familiar body (S/F). Focal males infrequently attacked familiar-face models but frequently attacked stranger-face models, regardless of body types. These behavioral reactions indicate that guppy males discriminate between familiar and stranger males by their face, not body coloration with wide variation. Importantly, male faces contain clear individual-variation in white/metallic colored patches on the operculum visible for humans. Considering the photo-model, our results suggest that these patches might be an important visual stimulus for face-recognition in guppy males, like some cichlids. Comparative examination among males of different guppy variants, including wild type phenotype, suggests that the face color-patch is stable regardless of variation in body color, with a different genetic mechanism potentially underlying face and body colors.
{"title":"Male Guppies Recognize Familiar Conspecific Males by Their Face.","authors":"Shumpei Sogawa, Rio Fukushima, Will Sowersby, Satoshi Awata, Kento Kawasaka, Masanori Kohda","doi":"10.2108/zs220088","DOIUrl":"https://doi.org/10.2108/zs220088","url":null,"abstract":"<p><p>Individual recognition is a necessary cognitive ability for the maintenance of stable social relationships. Recent studies have shown that like primates, some fish species can distinguish familiar fish from unfamiliar strangers via face-recognition. However, the taxa of the studied fish species are restricted (within Perciformes) and the visual signal used for the recognition of fish remains unclear. Here, we investigated the visual signal for individual-recognition in males of a sexually dichromatic guppy (<i>Poecilia reticulata</i>, Cyprinodontiformes). Using guppy males, we examined the hypothesis that fish distinguish between familiar individuals and unknown strangers by their faces rather than by body coloration. We randomly presented focal fish with four types of composite photo-models: familiar (familiar-face and familiar-body = F/F), stranger (stranger-face and stranger-body = S/S), familiar face combined with stranger body (F/S) and stranger face combined with familiar body (S/F). Focal males infrequently attacked familiar-face models but frequently attacked stranger-face models, regardless of body types. These behavioral reactions indicate that guppy males discriminate between familiar and stranger males by their face, not body coloration with wide variation. Importantly, male faces contain clear individual-variation in white/metallic colored patches on the operculum visible for humans. Considering the photo-model, our results suggest that these patches might be an important visual stimulus for face-recognition in guppy males, like some cichlids. Comparative examination among males of different guppy variants, including wild type phenotype, suggests that the face color-patch is stable regardless of variation in body color, with a different genetic mechanism potentially underlying face and body colors.</p>","PeriodicalId":24040,"journal":{"name":"Zoological Science","volume":"40 2","pages":"168-174"},"PeriodicalIF":0.9,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9661846","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}
Vertebrates generally possess hypophysiotropic and non-hypophysiotropic gonadotropin releasing hormone (GnRH) neurons. The terminal nerve (TN) GnRH neurons are known to belong to the non-hypophysiotropic neurons and have been suggested to modulate sexual behaviors. These neurons show spontaneous pacemaker firing activity and release neuropeptides GnRH and neuropeptide FF. Since the spontaneous firing activities of peptidergic neurons, including GnRH neurons, are believed to play important roles in the release of neuropeptides, understanding the regulatory mechanisms of these spontaneous firing activities is important. Here, we analyzed firing activities of the TN-GnRH neurons in medaka during application of acetylcholine (ACh), which is one of the essential neuromodulators in the brain. Whole cell patch clamp recording of TN-GnRH neurons demonstrated that ACh induces hyperpolarization and inhibits their pacemaker firing. Electrophysiological analysis using an antagonist for acetylcholine receptors and in situ hybridization analysis showed that firing of TN-GnRH neurons is inhibited via M2-type muscarinic acetylcholine receptor. These findings, taken together with literature from several other fish species (including teleosts and elasmobranchs), indicate that ACh may generally play an inhibitory role in modulating spontaneous activities of TN-GnRH neurons and thereby sexual behaviors in fish.
{"title":"Acetylcholine Inhibits Spontaneous Firing Activity of Terminal Nerve GnRH Neurons in Medaka.","authors":"Aiki Tanaka, Chie Umatani, Yoshitaka Oka","doi":"10.2108/zs220070","DOIUrl":"https://doi.org/10.2108/zs220070","url":null,"abstract":"<p><p>Vertebrates generally possess hypophysiotropic and non-hypophysiotropic gonadotropin releasing hormone (GnRH) neurons. The terminal nerve (TN) GnRH neurons are known to belong to the non-hypophysiotropic neurons and have been suggested to modulate sexual behaviors. These neurons show spontaneous pacemaker firing activity and release neuropeptides GnRH and neuropeptide FF. Since the spontaneous firing activities of peptidergic neurons, including GnRH neurons, are believed to play important roles in the release of neuropeptides, understanding the regulatory mechanisms of these spontaneous firing activities is important. Here, we analyzed firing activities of the TN-GnRH neurons in medaka during application of acetylcholine (ACh), which is one of the essential neuromodulators in the brain. Whole cell patch clamp recording of TN-GnRH neurons demonstrated that ACh induces hyperpolarization and inhibits their pacemaker firing. Electrophysiological analysis using an antagonist for acetylcholine receptors and in situ hybridization analysis showed that firing of TN-GnRH neurons is inhibited via M2-type muscarinic acetylcholine receptor. These findings, taken together with literature from several other fish species (including teleosts and elasmobranchs), indicate that ACh may generally play an inhibitory role in modulating spontaneous activities of TN-GnRH neurons and thereby sexual behaviors in fish.</p>","PeriodicalId":24040,"journal":{"name":"Zoological Science","volume":"40 2","pages":"151-159"},"PeriodicalIF":0.9,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9292074","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}