Not all ctenophores are hermaphrodites. Studies on the systematics, distribution, sexuality and development of two species of Ocyropsis

  title={Not all ctenophores are hermaphrodites. Studies on the systematics, distribution, sexuality and development of two species of Ocyropsis},
  author={Gr. Harbison and R. Lance Miller},
  journal={Marine Biology},
The lobate ctenophores Ocyropsis maculata and O. crystallina are not simultaneous hermaphrodites, based on morphological, histological and experimental evidence. Sex ratios in populations, sex ratios of size classes within populations, and average sizes of males and females support the hypothesis that both species are dioecious, rather than sequential hermaphrodites. We have divided each species into two subspecies, based on morphology and geographic distribution. Preliminary evidence suggests… Expand
Evidence of dioecy in the mesopelagic ctenophore Bathocyroe fosteri (Lobata Ctenophora)
Observations suggest that ctenophore dioecy is not restricted to the epipelagic, oceanic habitat and is not a property of a single genus with atypically located gonads, and has apparently evolved secondarily at least twice in habitats largely occupied by a group of related ctenphores. Expand
Reproductive characteristics of the lobate ctenophore Bolinopsis mikado (Moser)
The EPR increased lin- early with ctenophore size, i.e. the wet-weight specific EPR (EPR*) was independent of the body size, and was considerably higher than that of the respiration, predation, and growth rates, which may lead to quick population growth and mass occurrence of B. mikado during summer and fall in coastal waters. Expand
A vanished history of skeletonization in Cambrian comb jellies
This clade reveals a cryptic history and sheds new light on the early evolution of this basal animal phylum and is resolved as a monophyletic group (Scleroctenophora new class) within the ctenophores. Expand
In situ observations of foraging, feeding, and escape behavior in three orders of oceanic ctenophores: Lobata, Cestida, and Beroida
The foraging, feeding, and escape behaviors of members of four genera of oceanic ctenophores were studied by direct observation in the field during the summer of 1987 (7 July to 7 September) on R. V.Expand
What Are Jellyfishes and Thaliaceans and Why Do They Bloom
The evolutionary relationships among gelatinous zooplankton are summarized, biological factors that likely contribute to blooms are emphasized, and a population genetic framework for investigating the ecological causes of boom and bust population dynamics in the plankton is outlined. Expand
A molecular phylogenetic framework for the phylum Ctenophora using 18S rRNA genes.
The first molecular phylogenetic analysis of the phylum Ctenophora, by use of 18S ribosomal RNA sequences from most of the major taxa, suggests that the ctenophores form a distinct monophyletic group that is most closely related to the cnidarians. Expand
A reconstruction of sexual modes throughout animal evolution
The results suggest that mutations promoting hermaphroditism have historically been more likely to invade gonochoristic populations than vice versa and provide a framework for future inquiries into the correlation of these transitions with genes, behaviors, and physiology. Expand
An updated checklist of ctenophores (Ctenophora: Nuda and Tentaculata) of Mexican seas
Abstract Ctenophores are one of the most conspicuous and frequent groups of the gelatinous zooplankton community, but their regional diversity in tropical and subtropical latitudes remains largelyExpand
Multiple introductions and invasion pathways for the invasive ctenophore Mnemiopsis leidyi in Eurasia
The relatively high genetic diversity observed in introduced populations is consistent with large inocula and/or multiple invasions, both of which are possible given ballast water transport and the extensive native distribution of the ctenophore in the Atlantic Ocean. Expand
A synthesis of growth rates in marine epipelagic invertebrate zooplankton.
The most extensive study to date of globally compiled and analysed weight-specific growth rates in marine epi-pelagic invertebrate metazoan zooplankton, which generally confirms that larvaceans, pteropods, cnidarians and ctenophores have rates of weight- specific growth that are typically greater than the copepods, chaetognaths and other crustaceans of similar carbon weight. Expand


On the natural history and distribution of oceanic ctenophores
Abstract Oceanic ctenophores show aa great diversity in feeding biology, ranging from Leucothea multicornis , which can eat only small copepods, to species of Ocyropsis , which can capture and ingestExpand
It is considered probable that the ctenophore Ocyropsis has a closer phylogenetic relation with Bolinopsis, its ancestral form being probably derived from a primitive cydippid of a remote antiguity. Expand
Identification of sibling species within the “Sarsia tubulosa complex” at Friday Harbor, Washington (Hydrozoa: Anthomedusae)
The hybridization experiments do reveal a relationship between the level of species specificity of sperm attraction and the amount of hybridization, suggesting that sperm chemotaxis plays a role in fertilization in these animals. Expand
Simultaneous hermaphroditism; cost and benefit.
  • D. J. Heath
  • Biology, Medicine
  • Journal of theoretical biology
  • 1977
It is argued that externally fertilizing species should as a rule be gonochoric and that species which brood their young may often be hermaphroditic, and suggested that gonochorism and sexual dimorphism may result in more progeny being reared. Expand
Sperm chemotaxis in the hydromedusae. I. Species-specificity and sperm behavior
Egg extracts from 32 species of marine hydromedusae, siphonophores and sessile hydroids were tested for sperm attracting activity using the sperm of all species in both homo- and heterospecificExpand
Distribution and abundance of the ctenophore, Mnemiopsis leidyi in Narragansett Bay
The field evidence indicated that the population increases first in the upper bay and then spreads toward the mouth by mid-summer, while the overwintering population was extremely low and underwent a dramatic increase during summer and reached peak densities in early fall. Expand
It is estimated that sperm chemotaxis in O. dioica increases the chance of sperm-egg collisions from 4 to 15 times, mainly due to a increase in apparent diameter of the egg and also to an increase in the velocity of attracted sperm. Expand
The development of bioluminescence in the ctenophore Mnemiopsis leidyi.
The events that are responsible for the differential division during the formation of the 8-cell stage embryo have been studied by centrifuging eggs to produce fragments of different cytoplasmic composition. Expand
Sex reversal in a freshwater sponge.
Spongilla lacustris exhibits a type of alternative hermaphroditism, new to the phylum, in which a sponge may be exclusively male or female during the period of sexual reproduction one year and theExpand
Nutritional Ecology of Ctenophores—A Review of Recent Research
Publisher Summary This chapter summarizes information on nutritional biology (from observations on living animals mostly in the laboratory) of ctenophores and discusses attempts to utilize laboratoryExpand