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1.
Zoolog Sci ; 38(4): 352-358, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34342956

RESUMO

A new species of brittle star, Ophiodelos okayoshitakai, is described from two specimens collected in Sagami Bay, central-eastern Japan. Photographic examination of the holotype specimen of the sole other congener, Ophiodelos insignis Koehler, 1930, indicates that Ophiodelos okayoshitakai sp. nov. is distinguished from O. insignis by i) the disc stumps covering on the dorsal side of the disc, ii) the dorsal and ventral arm plates being separated from each other on the proximal arm regions, iii) the dorsal arm plate being smooth, iv) the arm spines at proximal portion of the arm being six in number and smooth in shape, and v) the number and shape of the tentacle scales at proximal portion of the arm being up to two and spine-shaped adradially and oval abradially. Detailed morphological observations of this new species suggest the inclusion of Ophiodelos, whose familial affiliation remains unclear, in the suborder Ophiacanthina. More than 10 juveniles of various sizes were found in the disc of Ophiodelos okayoshitakai sp. nov., indicating a brooding reproduction. This is the first report of the genus Ophiodelos from Japanese waters. We also provided a nucleotide sequence for part of the cytochrome c oxidase subunit I (COI) gene in O. okayoshitakai sp. nov. for future studies of DNA barcoding and phylogeny.


Assuntos
Equinodermos/fisiologia , Reprodução/fisiologia , Animais , Japão , Oceano Pacífico
2.
J Morphol ; 282(2): 205-216, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33159480

RESUMO

Basket stars, that is, Ophiuroidea in Echinodermata, exhibit distinctive morphological characteristics with their complicatedly branched arms that can regenerate immediately after mutilation. Although, in brittle stars, that is, ophiuroids with nonbranched arms, the arm regeneration process following accidental trauma or autotomy have been morphologically and histologically observed in several species, few studies have so far been carried out on the regeneration of branched arms in basket stars. In this study, the developmental and morphological features of arm regeneration in Astrocladus dofleini (Gorgonocephalidae, Euryalida, Euryophiurida), one of the most common basket star species in Japanese waters, was anatomically and histologically investigated. Results clearly showed the following phases during the arm regeneration: (a) repair phase, (b) early regenerative phase, (c) intermediate regenerative phase, (d) advanced regenerative Phase I, and (e) advanced regenerative Phase II. The morphogenetic process during the arm regeneration in the basket star showed similar patterns to those of nonbranched arms observed in other ophiuroids. However, differences were also seen between the two ophiuroid types, that is, there were some developmental features specific to the basket star. In the early regenerative phase, branching of coelomic cavities was observed prior to the formation of other tissues, probably inducing the later morphogenesis of branched arms. In addition, hard skeletal ossicles form rapidly at the advanced regenerative Phase II. These developmental features may have led the evolution of bizarre morphologies seen in basket stars, probably contributing to the adaptation to shallow waters from deep-sea habitats.


Assuntos
Equinodermos/anatomia & histologia , Equinodermos/fisiologia , Morfogênese , Animais , Equinodermos/citologia , Sistema Musculoesquelético/anatomia & histologia , Regeneração
3.
PeerJ ; 8: e9836, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33083106

RESUMO

Japanese species of the genus Astrocladus (Echinodermata, Ophiuroidea, Euryalida, Gorgonocephalidae) are reviewed. Astrocladus coniferus recently has two junior synonyms, A. dofleini Döderlein and A. pardalis Döderlein, however, status of these species has long been questioned. These species concepts have not been reviewed in recent years and no molecular phylogenetic analyses have been performed. Observations of the lectotype of A. coniferus, as well as the lectotype and four paralectotypes of A. dofleini and the holotype of A. pardalis have revealed that A. coniferus and A. pardalis are conspecific and morphologically distinguishable from A. dofleini. Astrocladus coniferus and A. dofleini are supported as distinct species by our molecular data. Additionally, we re-describe A. exiguus and A. annulatus, based on recently collected specimens and the holotype. We conclude that four species, A. annulatus, A. coniferus, A. dofleini, and A. exiguus are present in Japanese waters.

4.
J Plant Res ; 133(5): 639-648, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32623531

RESUMO

Nitrogen (N) resorption from senescing leaves enables plants to reuse N, thereby making them less dependent on current N uptake from the environment. Therefore, N resorption is important for survival and fitness, particularly for plants growing under low N supply. We studied N resorption from senescing leaves of 25 legumes and 25 nonlegumes in a temperate region of Japan to test the hypothesis that high N resorption has not evolved in legumes that fix atmospheric N2. The extent of N resorption was quantified by N resorption proficiency that is measured as the level to which leaf N concentration was reduced during senescence, i.e., the lower the senesced leaf N concentration, the lower the N loss through leaf fall and higher the N resorption proficiency. In support of the hypothesis, senesced leaf N concentration was higher in legumes than in nonlegumes, but there was considerable overlap between the groups. The higher senesced leaf N concentration of legumes was associated with a lower proportion of leaf N resorbed during senescence, particularly in species with higher leaf N concentrations. According to a hierarchical partitioning analysis, there was a large contribution of species to the total variance in the senesced leaf N concentration as opposed to a minor contribution of functional group (legume/nonlegume). This study reveals that legumes are not proficient at resorbing N from senescing leaves but that N2-fixation might not be the single most important determinant of N resorption.


Assuntos
Fabaceae , Nitrogênio , Fabaceae/metabolismo , Japão , Nitrogênio/metabolismo , Fósforo , Folhas de Planta
5.
Zootaxa ; 4571(1): zootaxa.4571.1.5, 2019 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-31715831

RESUMO

The ophiuroid species listed were collected by benthic faunal surveys from 2016 to 2018 in submarine caves of the Ryukyu Islands, southwestern Japan. The material includes 20 species from 8 families, Amphiuridae, Ophiocomidae, Ophiodermatidae, Ophiolepididae, Ophioleucidae, Ophiomyxidae, Ophionereididae and Ophiotrichidae. This is the first comprehensive report of submarine cave-dwelling ophiuroids from Japanese waters. Also provided is a redescription of a rare species, Dougaloplus echinatus (Ljungman, 1867), with a detailed description of its ossicle morphology. The species has previously been reported from Brazil, Australia, Eastern Indian Ocean to Southern China, in 11-118 m depth, and this is the first record of D. echinatus from Japanese waters. A brief discussion of the scarcity of submarine cave systems, and the need for their conservation, is provided.


Assuntos
Cavernas , Equinodermos , Animais , Austrália , Brasil , China , Oceano Índico , Ilhas , Japão
6.
Zootaxa ; 4695(5): zootaxa.4695.5.7, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31719338

RESUMO

We describe the first occurrence of the widely occurring brittlestar Ophiactis savignyi (Müller Troschel, 1842) as epibionts on Caretta caretta (Linnaeus, 1758), the loggerhead sea turtles. On the sea turtle epibionts, the coronulid barnacles were well studied as listed in Hayashi (2013), and recently some crustaceans were collected from loggerhead sea turtles and described as new species (Tanabe et al. 2017; Tanaka and Hayashi 2019). In contrast, echinoderm epibionts listed from sea turtles are poorly understood (Table 1) and this study represents the novel discovery of an ophiuroid, which was not previously known to occur on the surface of this species.


Assuntos
Thoracica , Tartarugas , Animais , Equinodermos
7.
Zoolog Sci ; 35(2): 179-187, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29623787

RESUMO

Previous phylogenetic studies of the family Gorgonocephalidae (brittle stars and basket stars) have identified three subfamilies, Astrotominae, Astrothamninae, and Gorgonocephalinae. The genus Astroclon was tentatively assigned to the subfamily Astrothamninae in previous studies, but its morphology is enigmatic and molecular data of the genus was insufficient. Therefore, the systematic position of Astroclon required confirmation to reconstruct the accurate systematics of the Euryalida. In the present study, we sought to clarify the subfamilial classification in the family Gorgonocephalidae (Echinodermata: Ophiuroidea: Euryalida). We revisited molecular phylogenetics of the Gorgonocephalidae including Astroclon and the major taxa in the family. The molecular analysis supported monophyly of the two species of Astroclon and its clear separation from Astrothamninae. The two Astroclon species were also distinguished from the other two subfamilies, Astrotominae and Gorgonocephalinae. Astroclon and three other subfamilies were divided in the basal position of the Gorgonocephalidae, and were assigned to subfamilies. A new subfamily, Astrocloninae was monotypically established for Astroclon in addition to the previous three subfamilies. Morphology of the first ventral arm plates and tentacle pores also supported distinctiveness of the new subfamily.


Assuntos
Equinodermos/classificação , Filogenia , Animais , Equinodermos/anatomia & histologia , Equinodermos/genética , Evolução Molecular , Análise de Sequência de DNA
8.
Zootaxa ; 4377(1): 1-20, 2018 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-29690052

RESUMO

Two new species, Ophiolepis cavitata n. sp. and Ophiozonella cavernalis n. sp., are described from the specimens collected in shallow water submarine caves in the Ryukyu Islands, southwestern Japan. Ophiolepis cavitata n. sp. is distinguished from the other congeners in having prominent tubercle-shaped knobs on dorsal arm plates; two sizes of disc scales on the aboral disc, the larger surrounded by 3-8 times smaller disc scales; larger scales concave; radial shields wider than long; a trio of distinct scales present distal to each pair of radial shields; oral shields partly concave; 3 arm spines on proximal portion of the arms. Ophiozonella cavernalis n. sp. is distinguished from the other congeners in having polygonal, uniform size disc scales; oral shields almost as long as wide, shallow concave proximal sides that end in a fairly sharp point medially; arms about 9 times longer than disc diameter; 3 cylindrical arm spines, of which the oral most one is slightly larger than other 2 spines. Ophiozonella cavernalis n. sp. is the second finding of an anchialine-endemic ophiuroid and the first finding from the Pacific Ocean.


Assuntos
Equinodermos , Animais , Cavernas , Ilhas , Japão , Oceano Pacífico
9.
Zootaxa ; 4392(2): 289-310, 2018 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-29690406

RESUMO

A revision of the genus Astrodendrum Döderlein (Ophiuroidea, Euryalida, Gorgonocephalidae) is based on 14 specimens, including the holotypes of Astrodendrum galapagense A. H. Clark and Astroconus capense Mortensen and a syntype of Gorgonocephalus sagaminus Döderlein. A new species Astrodendrum spinulosum is described from the Pacific coast of Japan. It is distinguished from its congeners in having conical external ossicles on aboral side of the disc; bulges on lateral edges of proximal arms; 1 terminal projection on each arm spine of proximal portion of the arm; 2 or 3 secondary teeth on each hook-shaped arm spine of distal portion of the arm. A taxonomic key to all six species of the genus Astrodendrum is provided.


Assuntos
Equinodermos , Animais , Japão
10.
Zootaxa ; 4392(1): 1-27, 2018 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-29690414

RESUMO

Fourteen species of euryalids are reported from collections made in the eastern and western Indian Ocean during the International Indian Ocean Expedition. Three new species are described: Astrocladus goodingi from the Comoro Islands, Astrocladus socotrana from the northwestern Indian Ocean near the island of Socotra, and Astrocyclus somaliensis from off northeastern Somalia. Range extensions are documented for Asteronyx luzonicus, Astroglymma sculptum, Astrocladus ludwigi, Asteromorpha capensis and Squamophis amamiensis.


Assuntos
Equinodermos , Animais , Comores , Expedições , Oceano Índico , Ilhas , Somália
11.
Zookeys ; (663): 1-19, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28769615

RESUMO

The first morphological observation of a euryalid brittle star, Asteronyx loveni, using non-destructive X-ray micro-computed tomography (µCT) was performed. The body of euryalids is covered by thick skin, and it is very difficult to observe the ossicles without dissolving the skin. Computed tomography with micrometer resolution (approximately 4.5-15.4 µm) was used to construct 3D images of skeletal ossicles and soft tissues in the ophiuroid's body. Shape and positional arrangement of taxonomically important ossicles were clearly observed without any damage to the body. Detailed pathways inside the vertebral ossicles, lateral arm plates, and arm spines for passage of nerves and water vascular structures were observed. Inter-vertebral muscles were also observed. Forms and 3D arrangements of many important taxonomical characters of the euryalids were scrutinized by µCT in high enough resolution for taxonomic description of ophiuroids.

12.
Zootaxa ; 4227(4): zootaxa.4227.4.4, 2017 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-28187565

RESUMO

The holotypes of Astrohelix bellator bellator and Astrohelix bellator paucidens (Echinodermata: Ophiuroidea: Euryalida: Gorgonocephalidae) are redescribed. Based on these observations Asteroporpa (Astromoana) with Astrohelix is proposed. With the elevation of two subspecies of Asteroporpa (Astrohelix) bellator bellator and A. (Astrohelix) bellator paucidens to species level, A. (Astrohelix) comprises six species, A. (Astrohelix) bellator, A. (Astrohelix) indicus, A. (Astrohelix) koyoae, A. (Astrohelix) muricatopatella, A. (Astrohelix) paucidens and A. (Astrohelix) reticulata. These species can be distinguished by the shape of the ossicles on the aboral disc, on the oral plates, and length of terminal projection of cone-shaped epidermal ossicles around the lateral interradial disc. A taxonomic key to all six species of the subgenus A. (Astrohelix) is provided.


Assuntos
Equinodermos , Animais
13.
Mol Phylogenet Evol ; 69(3): 566-80, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23906601

RESUMO

Previous molecular analysis of the order Euryalida (Echinodermata: Ophiuroidea), has identified three monophyletic families, the Euryalidae, Asteronychidae and Gorgonocephalidae. However, family-level relationships have remained unresolved due to inadequate taxon sampling and insufficient molecular markers. Here, we present a family-level revision of the Euryalida based on sequences from mitochondrial genes (16S rRNA and COI) and a nuclear gene (18S rRNA) from 83 euryalid ophiuroids. The monophyly of the three families, Euryalidae, Asteronychidae and Gorgonocephalidae is confirmed. The Euryalidae and Asteronychidae+Gorgonocephalidae are assigned to superfamilies, the Euryalidea and the Gorgonocephalidea, respectively. Three subclades within the family Gorgonocephalidae are identified and assigned to three subfamilies; Astrotominae includes Astrocrius, Astrohamma and Astrotoma, Astrothamninae (subfamily nov.) includes Astrothamnus and Astrothrombus with Gorgonocephalinae including the remaining genera. Morphological characters are consistent with the newly recognised superfamilies and subfamilies.


Assuntos
Equinodermos/classificação , Filogenia , Animais , Núcleo Celular/genética , DNA Mitocondrial/genética , Equinodermos/genética , Análise de Sequência de DNA
14.
Zookeys ; (129): 1-15, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21998552

RESUMO

Squamophis, a new genus of brittle star is described. Two species are included in the genus: Squamophis amamiensis (Okanishi & Fujita, 2009) from south-western Japan and Squamophis albozosteressp. n. from north-western Australia. Squamophisgen. n. is distinguished from the other genera of the family Asteroschematidae by the following characters: each radial shield is single-layered and is completely covered by plate-shaped epidermal ossicles, and the relative length of the longest arm spine throughout the arms is as long as the length of the corresponding arm segment. Squamophis albozosteressp. n. is distinguished from Squamophis amamiensis in having white, slightly domed, plate-shaped epidermal ossicles on the aboral side of the body, the ossicles on aboral and lateral portion of the arms form transverse rows, and the other part of aboral side of disc and basal to middle portion of arms are brown but tip of the arms are light purple.

15.
Mol Phylogenet Evol ; 61(2): 392-9, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21798356

RESUMO

The existing taxonomy of Euryalida, one of the two orders of the Ophiuroidea (Echinodermata), is uncertain and characterized by controversial delimitation of taxonomic ranks from genus to family-level. Their phylogeny was not studied in detail until now. We investigated a dataset of sequence from a mitochondrial gene (16S rRNA) and two nucleic genes (18S rRNA and 28S rRNA) for 49 euryalid ophiuroids and four outgroup species from the order Ophiurida. The monophyly of the order Euryalida was supported as was the monophyly of Asteronychidae, Gorgonocephalidae and an Asteroschematidae+Euryalidae clade. However, the group currently known as the Asteroschematidae was paraphyletic with respect to the Euryalidae. The Asteroschematidae+Euryalidae clade, which we recognise as an enlarged Euryalidae, contains three natural groups: the Asteroschematinae (Asteroschema and Ophiocreas), a new subfamily Astrocharinae (Astrocharis) and the Euryalinae with remaining genera. These subfamilies can be distinguished by internal ossicle morphology.


Assuntos
DNA Mitocondrial/genética , DNA Ribossômico/genética , Equinodermos/classificação , Filogenia , Animais , Núcleo Celular/genética , Equinodermos/genética , Genes de RNAr , Análise de Sequência de DNA
16.
Zoolog Sci ; 28(2): 148-57, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21303207

RESUMO

A revision of the genus Astrocharis Koehler (Echinodermata: Ophiuroidea: Asteroschematidae) is based on 41 specimens, including three syntypes of Astrocharis virgo Koehler, one syntype of Astrocharis ijimai Matsumoto and the holotype of Astrocharis gracilis Mortensen. Astrocharis gracilis is a junior subjective synonym of A. ijimai. A. virgo and A. ijimai are redescribed. A new species, Astrocharis monospinosa is described from southwestern Japan. A tabular key to the three species of the genus Astrocharis is provided.


Assuntos
Estrelas-do-Mar/anatomia & histologia , Estrelas-do-Mar/classificação , Animais , Demografia , Japão , Oceano Pacífico
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