Associations between pycnogonids and hydroids from the Buenos Aires littoral zone, with observations on the semi-parasitic life cycle of &lt;i&gt;Tanystylum orbiculare&lt;/i&gt;(Ammotheiidae)

Genzano, Gabriel N.

doi:10.3989/scimar.2002.66n183

Cited by 25 publications

(18 citation statements)

References 11 publications

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“…Two of the species treated here (Ammothea hilgendorfi and Nymphopsis spinosissima) prey on hydroids (Prell, 1909;Russel and Hedgpeth, 1990;Bain, 1991), Endeis spinosa is a surface grazer, and Austrodecus glaciale has been observed to pierce the anterior pores of polyzoa to gain access to the encased body (Fry, 1965). Tanystylum orbiculare has also been found as parasite-predator of hydroids (Genzano, 2002).…”

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confidence: 99%

Microscopic anatomy of pycnogonida: II. Digestive system. III. Excretory system

Fahrenbach

Arango

2007

Journal of Morphology

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The digestive system of several species of sea spiders (Pycnogonida, Arthropoda) was studied by electron microscopy. It is composed of the foregut inside a long proboscis, a midgut and a hindgut. Lips near the three jaws at the tip of the proboscis receive several hundred ductules originating from salivary glands. These previously undetected glands open on the lips, a fluted, projecting ridge at the external hinge line of the jaws, i.e., to the outside of the mouth. This disposition suggests affinities to the chelicerate line. The trigonal esophagus within the proboscis contains a complex, setose filter device, operated by dedicated muscles, that serves to reduce ingested food to subcellular dimensions. The midgut has diverticula into the bases of all legs. Its cells differentiate from the basal layer and contain a bewildering array of secretion droplets, lysosomes and phagosomes. In the absence of a hepatopancreas, the midgut serves both digestive and absorptive functions. The cuticle-lined hindgut lies in the highly reduced, peg-like abdomen. Traditionally, pycnogonids have been claimed to have no excretory organ at all. Such a structure, however, has been located in at least one ammotheid, Nymphopsis spinosissima, in which a simple, but standard, excretory gland has been found in the scape of the chelifore. It consists of an end sac, a straight proximal tubule, a short distal tubule, and a raised nephropore. The end sac is a thin-walled and polygonal chamber, about 150 microm in cross section, suspended in the hemocoel of the appendage, its edges radially tethered to the cuticle at more than half a dozen locations. This wall consists of a filtration basement membrane, 1-4 microm thick, facing the hemocoel, and internally of a continuous carpet of podocytes and their pedicels. The podocytes, measuring maximally 10 by 15 microm, have complex contents, of which a labyrinthine system of connected intracellular channels stands out. These coated cisternae open into a central vacuole that often rivals the nucleus in size. The design of the organ closely approximates that of the primitive crustacean Hutchinsoniella macracantha.

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confidence: 99%

Microscopic anatomy of pycnogonida: II. Digestive system. III. Excretory system

Fahrenbach

Arango

2007

Journal of Morphology

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“…Temporal variation of species richness in assemblages of benthic hydroids has already been described, and two types of species in Hydrozoa have been recognized: species recruiting to new surfaces year-round, and species doing so sporadically and without strong seasonality (Migotto et al 2001;Fernandez et al 2014). Reasons for these different scenarios are not clear, but one could hypothesize that wide distributions of hydroid species may be due to the many different strategies of asexual and sexual reproduction in complex life cycles including polyp and/or medusa/medusoid stages (Gili & Hughes 1995), and their great capacity to colonize different substrates (viz., Gili & Hughes 1995;Genzano & Rodriguez 1998;Migotto et al 2001;Genzano 2002;Oliveira & Marques 2007, 2011. Cornelius (1992) discussed rafting on floating objects and resting stages of hydroids together with the medusa loss in hydrozoan lineages, emphasizing the wide distribution patterns presented by benthic stages without medusae in their life cycle.…”

Section: Discussionmentioning

confidence: 99%

Areas of endemism in the Southwestern Atlantic Ocean based on the distribution of benthic hydroids (Cnidaria: Hydrozoa)

Miranda

Genzano

Marques

2015

Zootaxa

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Geographic distributions of 130 species of benthic hydroids were used to infer areas of endemism in the Southwestern Atlantic Ocean (SWAO, between 22°S and 55°S). Endemicity Analysis (EA) was carried out with the software NDM VNDM, using a 2° x 2° grid with different values of F (F = 0.5 and F = 1.0) for inferred presence. Hypothesized areas of endemism (16 with F = 0.5 and 13 with F = 1.0) formed three generalized patterns: (1) Tropical, (2) Subtropical, and (3) disjunctions along Tropical and Subtropical areas. Areas of endemism estimated here were compared with provinces, ecoregions and areas of endemism previously defined (but not based on algorithmic analysis) in the literature. Ecological and historical aspects that are potentially relevant for the SWAO realm were contrasted, related and discussed to areas of endemism. This is the first study to apply NDM VNDM to the marine realm and one of the few that focuses on the SWAO.

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“…2 The endoparasitic association between Pycnogonida and Cnidaria has been minimally investigated. The few studies regarding this association are mainly devoted to the description of the Pycnogonida life cycle (Russel & Hedgpeth 1990, Genzano 2002, Lovely 2005; therefore, whether endoparasites affect the development or growth of the hydroid colony is not clarified. Both the parasitized and desparasitized colonies of Podocoryna n. sp.…”

Section: Discussionmentioning

confidence: 99%

“…Pycnogonida/hydroid endoparasitism is characterized by the development of the pycnogonid protonymph inside the gastrovascular cavity of polyps, typically gastrozooids. These parasitized polyps are called gallzooids (Staples & Watson 1987, Genzano 2002, Heb & Melzer 2003.…”

Section: Introductionmentioning

confidence: 99%

First record of endoparasitism of Pycnogonida in Hydrozoan polyps (Cnidaria) from the Brazilian coast

Bettim

Haddad

2013

Biota Neotrop.

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Abstract:Despite the relatively high number of recent studies on Cnidaria off the Brazilian coast, we have observed only two records of parasitism on macromedusae and none on polyps. Endoparasitic associations between Pycnogonida larvae and hydroids have been well known since the early 20 th century. Protonymph larvae develop inside the gastrovascular cavity of polyps, typically gastrozooids, which are then called gallzooids. This short communication is an unprecedented record of parasitism on the polyps of Brazilian cnidarian fauna. The parasitic association between Pycnogonida Anoplodactylus stictus and a new hydroid species of Podocoryna has been casually detected on the encrusting communities of experimental polyethylene plates installed at the Paranaguá Yacht Club, Paranaguá, south of Brazil from February 2007 to February 2008. This hydrozoan host is most likely an exotic species because it had not been observed in previous studies of Paranaguá Bay or beaches along the southern coast of Brazil in the previous 20 years. Eighty-eight hydroid colonies were analyzed, of which 19 were parasitized mainly from June to August 2007. Protonymphs were pink-red colored, similar to gallzooids and all other polyps of the colony, thus indicating that they had eaten the hosts' tissues. Up to six protonymphs were observed inside the gallzooids. The gallzooid column was elongated, and the tentacles were atrophied or even absent because of the development of the larvae. Some observations of endoparasitism in two live colonies that were maintained in aquaria until their complete disappearance (one month) are also described in this note. Resumo: Apesar do número relativamente elevado de estudos recentes sobre Cnidaria da costa brasileira, encontramos dois casos de parasitismo, ambos em macromedusas, e nenhum em pólipos. Associações endoparasíticas entre larvas de picnogônidas e hidroides são bem conhecidas desde início do século 20. A larva protoninfa desenvolve-se no interior da cavidade gastrovascular dos pólipos, geralmente dos gastrozoóides, que são então chamados "gallzooids". Esta nota é um registro inédito de parasitismo em pólipos de cnidários da fauna brasileira. A associação parasitária entre o picnogônida Anoplodactylus stictus e uma espécie nova de hidroide do gênero Podocoryna foi detectada casualmente sobre a comunidade incrustante de placas experimentais, instaladas no Iate Clube de Paranaguá, Paranaguá, sul do Brasil, de fevereiro/2007 a fevereiro/2008. O hospedeiro hidrozoário provavelmente é uma espécie exótica, pois não havia sido observado em estudos anteriores da Baía de Paranaguá ou praias ao longo da costa sul do Brasil nos últimos 20 anos. Foram analisadas 88 colônias do hidroide das quais 19 estavam parasitadas, principalmente nos meses de junho a agosto/2007. As protoninfas eram rosa-avermelhadas, a mesma coloração dos "gallzooids" e dos demais pólipos da colônia, indicando que elas ingeriram tecidos do hospedeiro. Até seis protoninfas foram observados no interior dos "gallzooids". O comprimento da col...

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Associations between pycnogonids and hydroids from the Buenos Aires littoral zone, with observations on the semi-parasitic life cycle of <i>Tanystylum orbiculare</i>(Ammotheiidae)

Cited by 25 publications

References 11 publications

Microscopic anatomy of pycnogonida: II. Digestive system. III. Excretory system

Microscopic anatomy of pycnogonida: II. Digestive system. III. Excretory system

Areas of endemism in the Southwestern Atlantic Ocean based on the distribution of benthic hydroids (Cnidaria: Hydrozoa)

First record of endoparasitism of Pycnogonida in Hydrozoan polyps (Cnidaria) from the Brazilian coast

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