Reproductive cycle of Ophionereis reticulata (Ophiuroidea, Echinodermata) on the southeast coast of Brazil

The reproductive cycle of Ophionereis reticulata, a common sediment-rocky shore-interface ophiuroid, was examined monthly from January 2002 to January 2003 at Praia Grande beach (Sao Sesbatiao, state of Sao Paulo, Brazil). Mature individuals were found from January 2002 to April 2002 and from November 2002 to January 2003. Spawning was regcorded from January 2002 to March 2002 and from November 2002 to January 2003. Mature sperm is still present in April which could be involved in the fertilization of the last oocytes spawned in March and April. November and December marked the final point in the maturation process, with a high concentration of yolk and lipid nutrients in the oocytes. Ophionereis reticulata showed, for the period analyzed, a single spawning period, during spring and summer.

Antitropical distributions and species delimitation in a group of ophiocomid brittle stars (Echinodermata: Ophiuroidea: Ophiocomidae)

In this paper we examine the phylogeny and biogeography of the temperate genera of the Ophiocomidae (Echinodermata: Ophiuroidea) which have an interesting asymmetrical anti-tropical distribution, with two genera (Ophiocomina and Ophiopteris) previously considered to have a separate species in both the North and South hemispheres, and the third (Clarkcoma) diversifying in the southern Australian/New Zealand region. Our phylogeny, generated from one mitochondrial and two nuclear markers, revealed that Ophiopteris is sister to a mixed Ophiocomina/. Clarkcoma clade. Ophiocomina was polyphyletic, with O. nigra and an undescribed species from the South Atlantic Ocean sister to a clade including Clarkcoma species and O. australis. The phylogeny also revealed a number of recently diverged lineages occurring within Clarkcoma, some of which are considered to be cryptic species due to the similarity in morphology combined with the apparent absence of interbreeding in a sympatric distribution, while the status of others is less certain. The phylogeny provides support for two transequatorial events in the group under study. A molecular clock analysis places both events in the middle to late Miocene. The analysis excludes a tectonic vicariance hypothesis for the antitropical distribution associated with the breakup of Pangaea and also excludes the hypothesis of more recent gene flow associated with Plio/Pleistocene glacial cycling. © 2014 Elsevier Inc.

Taxonomy of Ophiuroidea (Echinonermata) from the continental shelf and slope of the southern and southeastern Brazilian coast

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ophiuroidea das regiões Antártica e Subantártica: 1. Sobre três espécies de Gorgonocephalidae e Ophiacanthidae

É estudada a distribuição geográfica e a variação de caracteres morfológicos de três espécies de ofiuroides (OpiLacantha antartica, Astrotoma agassizzi e Gorgonecephalus chilensis) das regiões Antártica e Subantãrtica. São também apresentadas observações sobre biologia reprodutiva.

Ophiuroidea das regiões Antártica e Subantártica: 2. Variação em Gorgonocephalus chilensis ( Philippi) (Echinodermata, Ophiuroidea, Gorgonocephalidae)

Foram examinados 198 exemplares de Gorgonocephalus chilensis das regiões antártica e subantartica, tendo-se em vista a variação de caracteres morfológicos externos. Foi constatada uma grande variação nas características morfológicas externas, que parece independer de localização geográfica.

Morfologia comparativa e distribuição batimétrica de duas espécies de Ophiuroidea, na região costeira de Ubatuba

Durante o período de outubro de 1985 a julho de 1987, foram coletados 722 ofíuróides pertencentes às espécies Ophioderma januarii e Ophioplocus januarii, na costa do Estado de São Paulo. Realizou-se medidas do diâmetro do disco dos exemplares e estas variaram entre 10,5 e 21,5 mm para Ophioderma januarii e entre 2,6 e 21,5 mm, para Ophioplocus januarii. Foram efetuadas observações das características morfológicas externas dos indivíduos e posteriormente, organizadas séries de crescimento, com o intuito de evidenciar possíveis alterações. Verificou-se para Ophioderma januarii, variações na forma dos escudos, no número de papilas orais e de espinhos braquiais, na coloração da superfície dorsal do disco e das placas braquiais dorsais e para Ophioplocus januarii variações nas escamas primárias, na série de escamas maiores da região interradial dorsal do disco, no número de escamas entre a centro-dorsal e a margem do disco, na forma dos escudos radiais e orais, no número de papilas orais, na coloração da superfície dorsal do disco e das placas braquiais dorsais. O resultado das análises de parâmetros ambientais dos locais de coleta, mostrou que as duas espécies ocorreram em áreas com condições ambientais distintas. Ophioderma januarii foi amostrada na região costeira até 36 m de profundidade e Ophioplocus januarii entre 30 e 100 m.

A new species of Ophlomisidium (Echinodermata : Ophiuroidea) from the continental shelf and slope off southern Brazil

A new species of Ophiomisidium is described and regards about reproduction are presented. It is the first species in the genus to posses, apparently,. a brooding development. Very few specimens of species of Ophiomisidium have previously been collected, but over 3000 specimens of the new species were collected on the continental shelf and slope (60-810 m depth) off southern Brazil. They were obtained during the REVIZEE Programme, the first extensive surveys to examine Brazilian ophiuroids from depths greater than 200 m.

Taxonomia, distribuição e biologia reprodutiva de Ophiuroidea (Echinodermata) das regiões Sudeste e Sul do Brasil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Arm regeneration in two populations of Ophionereis reticulata (Echinodermata, Ophiuroidea)

This study compared the arm regeneration frequencies in two different populations of Ophionereis reticulata (Say, 1825) in Sao Sebastiao, Southeast Brazil and observed arm regeneration between age classes (juvenile and adults) and sexes (male and female). From the 1,170 individuals sampled, 1,089 (92.2%) showed signs of arm regeneration. The relative frequencies of regenerating arms in the two areas were not different (Baleeiro Isthmus: 91.3% and Grande Beach: 99.5%). Both areas also presented similar values for the number of arms regenerating/individual and in the frequency of regenerating individuals. The major part of the regenerating scars was concentrated in the distal portion of the arm. Sub-lethal predation is most likely the cause to the high rates of arm regeneration in O. reticulata. There was no significant differences in the regeneration rates between females (3.57 +/- 1.36 arms regenerating/individual) and males (3.47 +/- 1.42).

Recruitment and growth variation of Ophionereis reticulata (Echinodermata: Ophiuroidea)

Two growth patterns are recognized in shallow-water ophiuroids: (I) slow growth and early reproductive maturity over a long life span and (2) rapid growth with a short life span. For species with the first pattern, both growth and recruitment would reflect a reproductive pattern with long periods of resting and spawning concentrated in certain months of the year. To evaluate this hypothesis, the recruitment, population dynamics, and growth of the intertidal brittle star Ophionereis reticulata were analyzed from January 2001 to December 2002 at the Baleciro Isthmus on the southeast coast of Brazil. The species shows an annual gametogenic cycle with spawning taking place in summer. Densities varied from 0.46 to 9.46 individuals m(-2). Density variations and seawater temperature were not significantly correlated. The population structure of O. reticulata was polymodal, with at least four co-occurring cohorts. Recruitment events were recorded in March 2001, October 2001, January 2002, and September 2002. As indicated by the asymptote size (D(infinity)=11.47 mm +/- 1.46), growth constant (K=0.42 year(-1)+/- 0.12), and oscillation index (C=0.97 +/- 0.51), the growth pattern of O. reticulata seems to be based on high survivorship of juveniles and adults, where sexual maturity is reached at a small size with rapid growth in the first 2 years of life. A low level of settlement is to be expected based on these data; however, there must be a minimum successful survivorship and development for juveniles and adults. Another explanation for the lack of small individuals (disc diameter <1.0 mm) could be that recruitment is located in a different area and a post-settlement migration might be involved in the maintenance of the population.