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Scanning electron microscopy images of teeth in Ophioplocus januarii . A) Dorsalmost tooth. B) Mid-positioned tooth. C) Proximal view of dorsal teeth. D) Proximal view of ventral teeth. E) Detail of B, showing the different calcite compaction. F) Fractured tooth. G) Detail of F, showing the internal differentiation in microstructure. I and II indicate regions of more compaction (I) and more porosity (II) of the calcite, respectively. Scale bars: A, B, C, D = 200 μm; E, G = 50 μm.
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Ophioplocus januarii is a common brittle star on soft and hard substrates along the Argentinian and Brazilian coasts. Based on stomach contents, tooth microstructure and field observations we identified its food. Opposed to previous suggestions, O. januarii appears to be a microphagous species feeding on macroalgal fragments (found in 60.0 % of the...
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Context 1
... microstructure analysis: All teeth in O. januarii revealed a fenestrated stereom microstructure ( Fig. 1). However, it was pos- sible to clearly identify two distinct regions: the basal parts of the teeth which are in contact with the dental plate, are more loosely perfo- rated than the distal parts. There the calcite is much more compacted, presenting a clear different arrangement (Fig. 1 A, B, C, D). This superficial distinction is ...
Context 2
... O. januarii revealed a fenestrated stereom microstructure ( Fig. 1). However, it was pos- sible to clearly identify two distinct regions: the basal parts of the teeth which are in contact with the dental plate, are more loosely perfo- rated than the distal parts. There the calcite is much more compacted, presenting a clear different arrangement (Fig. 1 A, B, C, D). This superficial distinction is visible also internally in the calcite microstructure as can be seen in a fractured tooth (Fig. 1 F, G). The basal surface presents little serrated edges, but at the distal portion these edges are less prominent because of the tightly packed calcite (Fig. 1 ...
Context 3
... basal parts of the teeth which are in contact with the dental plate, are more loosely perfo- rated than the distal parts. There the calcite is much more compacted, presenting a clear different arrangement (Fig. 1 A, B, C, D). This superficial distinction is visible also internally in the calcite microstructure as can be seen in a fractured tooth (Fig. 1 F, G). The basal surface presents little serrated edges, but at the distal portion these edges are less prominent because of the tightly packed calcite (Fig. 1 ...
Context 4
... presenting a clear different arrangement (Fig. 1 A, B, C, D). This superficial distinction is visible also internally in the calcite microstructure as can be seen in a fractured tooth (Fig. 1 F, G). The basal surface presents little serrated edges, but at the distal portion these edges are less prominent because of the tightly packed calcite (Fig. 1 ...
Context 5
... tooth stereom microstructure in O. januarii is distinctly different from that in teeth of macrophagous as well as microphagous spe- cies ( Fig. 1; Table 2). The presently found inter- mediate fenestrated arrangement of the stereom was also here observed for Ophiactis asperula, and confirmed as such when analyzing the teeth with the scanning electron microscope (SEM). The fact that SEM reveals structures which might remain disguised under the light microscope could explain that ...
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... be more specialized than deep-sea counterparts. For example, Ophioplocus januarii found in shallow northern Patagonia appears to be microphagous and omnivorous (Brogger et al., 2015). In intertidal areas of Madagascar, O. venosa feeds on Sargassum densifolium and on organic matter, whereas O. scolopendrina feeds on neuston (Fourgon et al., 2006). ...
... In intertidal areas of Madagascar, O. venosa feeds on Sargassum densifolium and on organic matter, whereas O. scolopendrina feeds on neuston (Fourgon et al., 2006). Many species have been reported to ingest live prey such as molluscs, annelids, crustaceans, or even other ophiuroids (Brogger et al., 2015;Pearson & Gage, 1984;Stöhr et al., 2012;Warner, 1982;Yokoyama & Amaral, 2008). Deep-dwelling ophiuroids display opportunistic and generalist behaviors with a feeding strategy centered on predation or suspension feeding (Gage & Tyler, 1991;Pearson & Gage, 1984). ...
Ophiopholis aculeata is a ubiquitous brittle star (Echinodermata: Ophiuroidea) known to occur from the upper subtidal to the bathyal zone. Individuals from shallow inshore habitats (rhodolith beds and rock fields) and deeper offshore locations in eastern Canada were studied to assess the population structure, habitat selection, diet, and feeding strategies of this species through use of stable isotope analyses, gut contents, and laboratory experiments. Potential drivers of habitat selection such as depth, light conditions, body size, sex, intraspecific competition, and presence of predators were examined. This study highlighted variable population size structures and abundances as well as diversified food sources and feeding strategies (i.e., suspension and deposit feeding, scavenging, predation on live organisms, and even cannibalism) as a function of native depth and habitat. It also revealed that studies on the feeding biology of brittle stars must carefully consider sex and life stage as driving factors.
... Although a relatively extensive amount of literature may be found on this topic (e.g. Deschuyteneer and Jangoux 1978;Chartock 1983;Emson 1990;Emson et al. 1991;Dearborn et al. 1996;Allen 1998;Boos 2012;Brogger et al. 2015), few studies have been conducted in the tropical Atlantic (Davis 1966;Reimer and Reimer 1975;Hendler 1982;Hendler and Miller 1984a;Yokoyama and Amaral 2008). In general, all papers analysing feeding biology in ophiuroids in detail, in both cold and warm waters, recorded a large variety of food items in the diet of these animals. ...
... In general, all papers analysing feeding biology in ophiuroids in detail, in both cold and warm waters, recorded a large variety of food items in the diet of these animals. The most common items are algae, crustaceans, echinoderms, gastropods and polychaetes (Feder 1981;Fratt and Dearborn 1984;Pearson and Gage 1984;Dearborn et al. 1996;Yokoyama and Amaral 2008;Harris et al. 2009;Brogger et al. 2015). ...
Ophioderma appressum is a common and abundant ophiuroid species in tropical reef
communities. Nevertheless, few studies analyse and describe its biology. In this paper, we
evaluate and describe the diet of this species collected at Seixas reefs, João Pessoa, Brazil. Monthly diurnal samples were obtained between September 2018 and July 2019. In total, 143 individuals were analysed. The recorded diet was variable and consisted of 24 taxa and two additional items. Most material represented unidentifiable and/or digested remains, foraminiferans, crustacean fragments, and sediment particles, indicating omnivory. The number of individuals with stomach contents varied along the year (from two to 13 specimens per month). There was also significant temporal variation in the composition of the stomach contents. The months September 2018, May 2019 and June 2019 had the highest variety of items during the study. Our results suggest generalist and opportunistic feeding behaviour and highlight the role of O. appressum as an active predator on prey of diverse taxa and body size.
... This is consistent with the hypothesis claiming that madreporites are ecologically informative (Ezhova et al. 2016). The differences among species in the type of teeth are relevant if we consider that teeth types have been used as an indicator of feeding preferences (uniform teeth for macrophagous feeders and compound for microphagous) (Medeiros-Bergen 1996;Brogger et al. 2015). Five ophionereidids have been reported to possess only compound teeth (Medeiros-Bergen 1996), while O. commutabilis shows both compound and uniform teeth, which could represent an adaptation, increasing the importance of omnivorous feeding in this cave system (as suggested by Bribiesca-Contreras et al. (2019) for other food sources). ...
Due to their peculiar and sometimes bizarre morphology, cave fauna (across invertebrates and vertebrates from both aquatic and terrestrial cave habitats) have fascinated researchers throughout history. Despite their success in colonizing most marine ecosystems, the adaptations of cave brittle stars (Ophiuroidea) to a stygobiotic lifestyle have been scarcely examined. Employing comparative methods on a data set of two species belonging to the genus Ophionereis , this study addresses whether a cave-dwelling species from Cozumel exhibited similar troglomorphic traits as those of other taxa inhabiting caves. Our work demonstrated that some characters representing potential morphological cave adaptations in O. commutabilis were: bigger sizes, elongation of arms and tube feet and the presence of traits potentially paedomorphic. In addition, an element of ophiuroid’s photoreceptor system, as well as pigmentation, was observed to be peculiar in this stygobiotic species, plausibly as a result of inhabiting a low light-energy environment. Finally, we add evidence to the statement that O. commutabilis is a cave endemic species, already supported by demography, distribution and origin of this species, and now by a typical array of troglomorphisms.
... The numbers in parentheses refer to the following comments: (1) The microstructure of type A and B tooth types has been described and illustrated with scanning electron micrographs by Medeiros-Bergen [36][37][38]. Most examined type B teeth have a cap consisting of imperforate stereom (Fig 1Cc), which has been described variously in the literature as "enamelled", "hyaline" or "glassy"; a cap consisting of more densely fenestrated stereom has been observed in Ophiopholis aculeata (Ophiopholidae), Ophiactis asperula (Ophiactidae), ophiolepidids have type A dental plates, one species has an "imperfect" perforation and another has distinctly type B perforations. ...
... https://doi.org/10.1371/journal.pone.0202046.g010 Acrocnida brachiata, Amphiura chiajei (both Amphiuridae) and Ophioplocus januarii (Hemieuryalidae) ( [37,39]; Wilkie pers. obs.) (Fig 1Dc). ...
... There are no comparable data on any type B IF. It is, however, intriguing that, even taking into account the trophic versatility demonstrated by many ophiuroids [67][68][69][70], suspension feeding features prominently and consistently in all clades with type B IFs (as shown in Fig 10), but sporadically, or not at all, in those with type A IFs (see inter alia [37,63,68,69,[71][72][73]). It has also been suggested that the capped teeth of type B IFs are an adaptation for the efficient comminution of material obtained by suspension or deposit feeding [36,64]. ...
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... This may indicate the broad food spectrum, unselective feeding behaviour and dependence of Ophiothrix spp. feeding preference to its habitat diversity (Brogger et al. 2015). Feeding preferences of brittle star is approximated by Brogger et al. (2015) as relatively poorly developed both on hard substrates and on soft sediments rich in detritus. ...
... feeding preference to its habitat diversity (Brogger et al. 2015). Feeding preferences of brittle star is approximated by Brogger et al. (2015) as relatively poorly developed both on hard substrates and on soft sediments rich in detritus. As a deposit feeder, Ophiothrix spp. ...
Increasing habitat modification and species loss demand consistent efforts to describe and understand biodiversity patterns. The BIOTA/FAPESP Program was created in this context and it has been a successful initiative to promote studies on biodiversity and conservation in Brazil. The BIOTA/Araçá is an interdisciplinary project that provided a detailed evaluation of the biodiversity of Araçá Bay, a coastal seascape located on the North coast of the state of São Paulo, Southeast Brazil. The bay encompasses multiple habitats, such as beaches, mangroves, rocky shores, and a tidal flat, and provides important ecosystem services. Unfortunately, the bay is the subject of complex social-environmental conflicts that oppose economic, social, and environmental demands (i.e., the expansion of neighboring harbor activities vs. small-scale artisanal fisheries and protection of biodiversity). The present study presents a survey of the benthic species occurring in the different habitats of Araçá Bay, including data obtained during the BIOTA/Araçá project and previous assessments of the area. The benthic species play an important role in marine environments and studying the diversity of these organisms that live associated with the bottom is indispensable for comprehending the environment’s functioning. The macrofauna, meiofauna, and microorganisms associated with soft and hard bottom were listed, and additional information, such as the habitat and geographical distribution, were provided for each species. The checklist includes 826 species, almost 70% recorded during the BIOTA/Araçá project. The most speciose taxa were the annelids (225 spp.), mollusks (194 spp.), and crustaceans (177 spp.). Seven benthic species are endemic to Araçá Bay, 14 are considered threatened, and seven are economically exploited. Furthermore, the bay is the type locality of many taxa, and 11 new benthic species were described based on specimens sampled during the project. This project shows the importance of Araçá Bay as a unique biologically rich environment and highlights the need for conservation efforts in light of the current threats.
Les algues brunes du genre Cystoseira sensu lato forment les écosystèmes marins, comptant parmi les plus productifs de Méditerranée, mais aussi parmi les plus menacés par les facteurs anthropiques et phénomènes globaux ; elles comptent aujourd’hui 45 espèces reconnues taxonomiquement, avec un nombre soumis à évolution, en raison des confusions taxonomiques récurrentes et de l’apport de la biologie moléculaire. Cette dernière a permis grâce aux récents travaux de distinguer trois genres : Cystoseira, Carpodesmia et Treptacantha. Notre étude qui a concerné un total de 29 Stations de la région centre, s’étendant du littoral de Chlef à l’Ouest au Littoral de Bejaia à l’est, ainsi que 3 stations additives à l’extrême est et ouest, a permis de recenser un total de 12 espèces, parmi les 16 citées dans la littérature. Le Treptacantha barbata, classé taxa excludenda, et signalé par de rares auteurs n’a été observé ni par Sellam (2018), ni par nous-mêmes, nous suggérons une confusion taxonomique avec le Cystoseira compressa subsp. Compressa ou le Cystoseira humilis. Un intérêt particulier a par ailleurs été dévolu à l’espèce endémique stricte Cystoseira sedoides, car très peu étudiée, elle a été recensée à 14 stations, où elle forme des faciès monospécifiques et 2 autres où elle est rare. L’analyse historique de son observation a révélé une tendance à la diminution, voire à la disparition dans les stations les plus urbanisées. Les résultats des mesures de densité et de matière sèche moyennes ont corroboré la nécessité de reconsidérer son statut écologique, d’espèce fondatrice, au même titre que le Cystoseira amentacea var. stricta et le Carpodesmia crinita. L’étude de la faune et de la flore associées a concerné les 4 formations clés du littoral algérien, l’association en mode battu à Cystoseira amentacea var. stricta, moyennement battu à Cystoseira sedoides et l’association à
Carpodesmia crinita et à Cystoseira humilis, en mode calme. L’examen de la diversité
floristique a permis d’énumérer un total de 94 espèces et de décrire les strates caractéristiques de chaque association. Un total de 160 espèces fauniques a été recensé, l’analyse comparative des indices de biodiversité calculés par la méthode d’interpolation et d’extrapolation, qui standardise la taille des échantillons, a révélé des différences non significatives entre les associations étudiées, hormis entre celles du Cystoseira amentacea var. stricta et du C. sedoides. L’approche comparative de la composition des peuplements a permis de mettre en évidence que le facteur hydrodynamique contribue significativement à la structure de la macrofaune associée, principalement fonctionnelle, liée au mode trophique des espèces, qui semble être un meilleur outil de caractérisation des peuplements fauniques associés.
The detailed study of arm ossicles, particularly the lateral arm plates, is providing valuable information in the elucidation of ophiuroid taxonomy. The present study describes in detail 16 species of brittle stars from Araçá Bay, Brazil. This information is used to construct the first interactive electronic key, providing a valuable resource for a broad range of researchers. Brittle stars families were divided into three groups based on their spatial distribution: i) infaunal species of intertidal and shallow subtidal belonging to Amphiuridae and Ophiactidae, ii) epizoic species belonging to Amphiuridae, Ophiactidae, and Ophiotrichidae and, iii) epifaunal species of the subtidal belonging to Ophiodermatidae and Hemieuryalidae. In the global context of recent revisions of ophiuroid taxonomy, the present work provides additional characters for use in future phylogenetic studies.
