76 research outputs found

    Embryonic, Larval, and Juvenile Development of the Sea Biscuit Clypeaster subdepressus (Echinodermata: Clypeasteroida)

    Get PDF
    Sea biscuits and sand dollars diverged from other irregular echinoids approximately 55 million years ago and rapidly dispersed to oceans worldwide. A series of morphological changes were associated with the occupation of sand beds such as flattening of the body, shortening of primary spines, multiplication of podia, and retention of the lantern of Aristotle into adulthood. To investigate the developmental basis of such morphological changes we documented the ontogeny of Clypeaster subdepressus. We obtained gametes from adult specimens by KCl injection and raised the embryos at 26C. Ciliated blastulae hatched 7.5 h after sperm entry. During gastrulation the archenteron elongated continuously while ectodermal red-pigmented cells migrated synchronously to the apical plate. Pluteus larvae began to feed in 3 d and were 20 d old at metamorphosis; starved larvae died 17 d after fertilization. Postlarval juveniles had neither mouth nor anus nor plates on the aboral side, except for the remnants of larval spicules, but their bilateral symmetry became evident after the resorption of larval tissues. Ossicles of the lantern were present and organized in 5 groups. Each group had 1 tooth, 2 demipyramids, and 2 epiphyses with a rotula in between. Early appendages consisted of 15 spines, 15 podia (2 types), and 5 sphaeridia. Podial types were distributed in accordance to Lovén's rule and the first podium of each ambulacrum was not encircled by the skeleton. Seven days after metamorphosis juveniles began to feed by rasping sand grains with the lantern. Juveniles survived in laboratory cultures for 9 months and died with wide, a single open sphaeridium per ambulacrum, aboral anus, and no differentiated food grooves or petaloids. Tracking the morphogenesis of early juveniles is a necessary step to elucidate the developmental mechanisms of echinoid growth and important groundwork to clarify homologies between irregular urchins

    Ctenostomatous Bryozoa from São Paulo, Brazil, with descriptions of twelve new\ud species

    Get PDF
    This paper describes 21 ctenostomatous bryozoans from the state of São Paulo, Brazil, based on specimens observed in vivo. A new family, Jebramellidae n. fam., is erected for a newly described genus and species, Jebramella angusta n. gen. et sp. Eleven other species are described as new: Alcyonidium exiguum n. sp., Alcyonidium pulvinatum n. sp., Alcyonidium torquatum n. sp., Alcyonidium vitreum n. sp., Bowerbankia ernsti n. sp., Bowerbankia evelinae n. sp., Bowerbankia mobilis n. sp., Nolella elizae n. sp., Panolicella brasiliensis n. sp., Sundanella rosea n. sp., Victorella araceae n. sp. Taxonomic and ecological notes are also included for nine previously described species: Aeverrillia setigera (Hincks, 1887), Alcyonidium hauffi Marcus, 1939, Alcyonidium polypylum Marcus, 1941, Anguinella palmata van Beneden, 1845, Arachnoidella evelinae (Marcus, 1937), Bantariella firmata (Marcus, 1938) n. comb., Nolella sawayai Marcus, 1938, Nolella stipata Gosse, 1855 and Zoobotryon verticillatum (delle Chiaje, 1822).Natural History Museum, London (U.K.)São Paulo Research Foundation (FAPESP) within the BIOTA/FAPESP─Virtual Institute of Biodiversity Program (www.biota.org.br) and BIOTA/FAPESP-Araça (grants # 1998/07090-3 and 2011/50317- 5 to A.C.Z. Amaral).CNPq (474605/2013-2)FAPESP (Proc.nº 2006/ 05141-8; 2008/10619-0; 2012/24285-1)CNPq (306568/2009-8)FAPESP (Proc.nº 2008/10624-3; 2012/10413-8)NP-BioMar, USPContribution No. 959 from the Smithsonian Marine Station at Fort Pierc

    Transitions in morphologies, fluid regimes, and feeding mechanisms during development of the medusa Lychnorhiza lucerna

    Get PDF
    Author Posting. © The Author(s), 2016. This is the author's version of the work. It is posted here by permission of Inter-Research for personal use, not for redistribution. The definitive version was published in Marine Ecology Progress Series 557 (2016): 145-159, doi:10.3354/meps11855.The early ontogeny of scyphomedusae involves morphological and functional transitions in body plans that affect the predators’ propulsive and feeding strategies. We applied high-speed videography, digital particle image velocimetry (DPIV) and dye visualization techniques to evaluate alterations in swimming and feeding mechanisms during ontogeny of the rhizostome medusa Lychnorhiza lucerna Haeckel, 1880 (Scyphozoa, Rhizostomeae). During early ontogeny, the ephyral mouth lips develop into complex filtering structures along the oral arms. The viscous environments (Reynolds number <100) experienced by ephyrae constrain the feeding mechanisms that transport fluid during ephyral bell pulsations. In contrast, adult medusan fluid flows are dominated by inertial forces and bell pulsations effectively transport fluids and entrained prey toward the oral arms. The oral arm surfaces are covered by motile epidermal cilia that drive these entrained flows through filtering gaps in the oral arms where food particles are retained. In addition to this process within the oral arms, vortices generated during bell pulsation flow downstream along the outside of the medusae and continuously transport prey toward the exterior oral arm surfaces. Although calanoid copepods are capable of escape velocities that greatly exceed L. lucerna’s feeding current speeds, copepods often fail to detect the predator’s feeding currents or inadvertently jump into medusan capture surfaces during failed escape attempts. Consequently, the comparatively weak predator feeding currents successfully capture a portion of the copepods encountered by swimming medusae. These results clarify the processes that enable rhizostome medusae to play key roles as consumers in tropical and subtropical coastal environments.The study was partially funded by grants 2011/00436-8, 2013/19478-8, and 2014/00824-6 São Paulo Research Foundation (FAPESP), and CAPES PROEX2017-09-2

    Evidence for Polyphyly of the Genus Scrupocellaria (Bryozoa: Candidae) Based on a phylogenetic Analysis of Morphological Characters

    Get PDF
    The bryozoan genus Scrupocellaria comprises about 80 species in the family Candidae. We propose a hypothesis for the phylogenetic relationships among species assigned to Scrupocellaria to serve as framework for a phylogenetic classification using 35 morphological characters. Our results suggest that the genus Scrupocellaria is polyphyletic. Scrupocellaria s. str. is redefined according to four morphological features: vibracular chamber with a curved setal groove, ooecium with a single ectooecial fenestra, two axillary vibracula, and a membranous operculum with a distinct distal rim. Thus, the genus includes\ud only 11 species: Scrupocellaria aegeensis, Scrupocellaria delilii, Scrupocellaria harmeri, Scrupocellaria incurvata, Scrupocellaria inermis, Scrupocellaria intermedia, Scrupocellaria jullieni, Scrupocellaria minuta, Scrupocellaria puelcha, Scrupocellaria scrupea,\ud and Scrupocellaria scruposa. The monophyly of Cradoscrupocellaria is supported and five new genera are erected: Aquiloniella n. gen., Aspiscellaria n. gen., Paralicornia n. gen., Pomocellaria n. gen. and Scrupocaberea n. gen. Two other new genera, Bathycellaria n. gen. and Sinocellaria n. gen., are erected to accommodate two poorly known species, Scrupocellaria profundis Osburn and Scrupocellaria uniseriata Liu, respectively. Scrupocellaria congesta is tentatively assigned to Tricellaria. Fifteen species are reassigned to Licornia: Licornia cookie n. comb., Licornia micheli n. comb., Licornia milneri n. comb.,\ud Licornia curvata n. comb., Licornia diegensis n. comb., Licornia drachi n. comb., Licornia mexicana n. comb., Licornia pugnax n. comb., Licornia raigadensis n. comb., Licornia regularis n. comb., Licornia resseri n. comb., Licornia securifera n. comb., Licornia\ud spinigera n. comb., Licornia tridentata n. comb., and Licornia wasinensis n. comb. Notoplites americanus n. name is proposed as a replacement name for Scrupocellaria clausa Canu & Bassler. Three fossil species are reassigned to Canda: Canda rathbuni\ud n. comb., Canda triangulata n. comb. and Canda williardi n. comb. A species is reassigned to Notoplites, Notoplites elegantissima n. comb. The generic assignment of eleven species of Scrupocellaria, including Scrupocellaria macandrei, remains uncertain.NP-BioMar, US

    Rapid assessment survey for exotic benthic species in the São Sebastião Channel, Brazil

    Get PDF
    The study of biological invasions can be roughly divided into three parts: detection, monitoring, mitigation. Here, our objectives were to describe the marine fauna of the area of the port of São Sebastião (on the northern coast of the state of São Paulo, in the São Sebastião Channel, SSC) to detect introduced species. Descriptions of the faunal community of the SSC with respect to native and allochthonous (invasive or potentially so) diversity are lacking for all invertebrate groups. Sampling was carried out by specialists within each taxonomic group, in December 2009, following the protocol of the Rapid Assessment Survey (RAS) in three areas with artificial structures as substrates. A total of 142 species were identified (61 native, 15 introduced, 62 cryptogenic, 4 not classified), of which 17 were Polychaeta (12, 1, 1, 3), 24 Ascidiacea (3, 6, 15, 0), 36 Bryozoa (17, 0, 18, 1), 27 Cmdana (2, 1, 24, 0), 20 Crustacea (11, 4, 5, 0), 2 Entoprocta (native), 16 Mollusca (13, 3, 0, 0). Twelve species are new occurrences for the SSC. Among the introduced taxa, two are new for coastal Brazil. Estimates of introduced taxa are conservative as the results of molecular studies suggest that some species previously considered cryptogenic are indeed introduced. We emphasize that the large number of cryptogenic species illustrates the need for a long-term monitoring program, especially in areas most susceptible to bioinvasion. We conclude that rapid assessment studies, even in relatively well-known regions, can be very useful for the detection of introduced species and we recommend that they be carried out on a larger scale in all ports with heavy ship traffic.Center of Marine Biology of the University of São Paulolhabela Yacht ClubCAPES-PROCAD 2007/150FAPESP (2004/09961-4; 2006/58226-0; 2010/06927-0)CAPES (Pró-Equipamentos and Prodoc projects)Boticário FoundationCNPqCAPESFAPESP (2008/10619-0)PNPD/CAPESFACEPE (BCT 0039-1.08/10)NP-BioMar, USPSpecial Issue: “Proceedings of the 3rd Brazilian Congress of Marine Biology”. A.C. Marques, L.V.C. Lotufo, P.C. Paiva, P.T.C. Chaves & S.N. Leitão (Guest Editors

    The life cycle of Clytia linearis

    No full text
    corecore