The Copepodid of Peniculisa Shiinoi Izawa, 1965 (Copepoda, Siphonostomatoida, Pennellidae), a Single Free-Swimming Larval Stage of the Species

Crustaceana ◽  
1997 ◽  
Vol 70 (8) ◽  
pp. 911-919 ◽  
Author(s):  
Kunihiko Izawa
Keyword(s):  
Larval Stage ◽  
Egg Size ◽  
Parasitic Copepod ◽  
Free Swimming ◽  
Nauplius Stage ◽  
Puffer Fish ◽  
Copepodid Stage

AbstractThe copepodid stage of the parasitic copepod Peniculisa shiinoi Izawa, 1965 (Siphonostomatoida, Pennellidae), parasitic on the fins of a puffer fish, Canthigaster rivulatus, is described based on specimens reared from eggs. This is the only free-swimming larval stage of P. shiinoi. The copepodid is distinctly smaller than those of the known pennellids. However, the dispensability of the free-swimming nauplius stage is independent of the egg-size. The copepodid antennae of the pennellids are certainly uniramous. The setation of the rami of the copepodid legs varies among pennellids.

The developmental stages of Neobrachiella robusta (Wilson, 1912), a parasitic copepod of Sebastes (Teleostei: Scorpaeniformes)

1987 ◽  
Vol 65 (6) ◽  
pp. 1331-1336
Author(s):  
Z. Kabata
Keyword(s):  
Life Cycle ◽  
Developmental Stages ◽  
Parasitic Copepod ◽  
Gill Arch ◽  
Gill Rakers ◽  
Copepodid Stage

The morphology of the developmental stages of Neobrachiella robusta (Wilson, 1912) (Copepoda: Siphonostomatoida) is described. The copepod is parasitic on the gill rakers of Sebastes alutus (Gilbert, 1890) (Teleostei: Scorpaeniformes). The life cycle of this copepod consists of a copepodid stage, followed by four chalimus stages and a relatively long preadult stage, which undergoes extensive metamorphosis. The copepods aggregate on the outer row of long gill rakers of the first gill arch, as many as 97% of them being attached to these rakers. Some of the rakers become distorted, but a connection between the presence of N. robusta and these abnormalities could not be established.

scholarly journals Geographical variation in larval host-plant use by Heliconius erato (Lepidoptera: Nymphalidae) and consequences for adult life history

2002 ◽  
Vol 62 (2) ◽  
pp. 321-332 ◽  
Author(s):  
D. RODRIGUES ◽  
G. R. P. MOREIRA
Keyword(s):  
Life History ◽  
Body Size ◽  
Larval Stage ◽  
Egg Size ◽  
Geographical Variation ◽  
Size Range ◽  
Adult Size ◽  
Experimental Station ◽  
Female Body Size ◽  
Adult Body

Adult body size, one of the most important life-history components, varies strongly within and between Heliconius erato phyllis (Lepidoptera: Nymphalidae) populations. This study determines if this variation is caused by geographical changes in host-plant used by the larval stage, whose reproductive parameters are influenced by female body size, with estimates of the corresponding heritability. The variation in adult body size was determined together with a survey of passion vine species (Passifloraceae) used by the larvae in seven localities in Rio Grande do Sul State: three located in the urban area of Porto Alegre and Triunfo Counties, two within Eucalyptus plantations (Barba Negra Forest, Barra do Ribeiro County, and Águas Belas Experimental Station -- Viamão County), one in a Myrtaceae Forest (Itapuã State Park -- Itapuã County) and one in the Atlantic Rain Forest (Maquiné Experimental Station -- Maquiné County). Effects of female body size on fecundity, egg size and egg viability were determined in an outdoor insectary. Size heritability was estimated by rearing in the laboratory offspring of individuals maintained in an insectary. The data showed that adults from populations where larvae feed only upon Passiflora suberosa are smaller than those that feed on Passiflora misera. The larvae prefer P. misera even when the dominant passion vine in a given place is P. suberosa. Fecundity increases linearly with the increase in size of females, but there is no size effect on egg size or viability. Size heritability is null for the adult size range occurring in the field. Thus, the geographical variation of H. erato phyllis adult size is primarily determined by the type, corresponding availability and quality of host-plants used by the larval stage. Within the natural size range of H. erato phyllis, the variation related to this caracter is not genetically based, thus being part of H. erato phyllis phenotypic plasticity.

scholarly journals The Pronephros; a Fresh Perspective

2019 ◽  
Vol 59 (1) ◽  
pp. 29-47 ◽  
Author(s):  
B S de Bakker ◽  
M J B van den Hoff ◽  
P D Vize ◽  
R J Oostra
Keyword(s):  
Larval Stage ◽  
Kidney Development ◽  
Current Knowledge ◽  
The Body ◽  
Human Embryos ◽  
Striking Difference ◽  
Extensive Literature ◽  
Free Swimming ◽  
Histological Sections ◽  
Study Results

Abstract Contemporary papers and book chapters on nephrology open with the assumption that human kidney development passes through three morphological stages: pronephros, mesonephros, and metanephros. Current knowledge of the human pronephros, however, appears to be based on only a hand full of human specimens. The ongoing use of variations in the definition of a pronephros hampers the interpretation of study results. Because of the increased interest in the anamniote pronephros as a genetic model for kidney organogenesis we aimed to provide an overview of the literature concerning kidney development and to clarify the existence of a pronephros in human embryos. We performed an extensive literature survey regarding vertebrate renal morphology and we investigated histological sections of human embryos between 2 and 8 weeks of development. To facilitate better understanding of the literature about kidney development, a referenced glossary with short definitions was composed. The most striking difference between pronephros versus meso- and metanephros is found in nephron architecture. The pronephros consists exclusively of non-integrated nephrons with external glomeruli, whereas meso- and metanephros are composed of integrated nephrons with internal glomeruli. Animals whose embryos have comparatively little yolk at their disposal and hence have a free-swimming larval stage do develop a pronephros that is dedicated to survival in aquatic environments. Species in which embryos do not have a free-swimming larval stage have embryos that are supplied with a large amount of yolk or that develop within the body of the parent. In those species the pronephros is usually absent, incompletely developed, and apparently functionless. Non-integrated nephrons were not identified in histological sections of human embryos. Therefore, we conclude that a true pronephros is not detectable in human embryos although the most cranial part of the amniote excretory organ is often confusingly referred to as pronephros. The term pronephros should be avoided in amniotes unless all elements for a functional pronephros are undeniably present.

On the development of a parasitic copepod, Lamproglena clariae Fryer, 1956 (Copepoda, Lernaeidae) infecting the sharp tooth catfish, Clarias gariepinus

Crustaceana ◽  
2013 ◽  
Vol 86 (4) ◽  
pp. 416-436 ◽  
Author(s):  
G. N. Madanire-Moyo ◽  
A. Avenant-Oldewage
Keyword(s):  
Clarias Gariepinus ◽  
Parasitic Copepod ◽  
Postembryonic Development ◽  
Fish Host ◽  
Artificial Infection ◽  
Abdominal Somite ◽  
Parasitic Copepods ◽  
Copepodid Stage ◽  
The Mean ◽  
Direct Life Cycle

The postembryonic development of the gill parasite, Lamproglena clariae, infecting the sharp tooth catfish, Clarias gariepinus was established from egg culture and artificial infection of fish under laboratory conditions. Like most fish parasitic copepods, L. clariae has a direct life cycle utilizing only a single fish host species. Adult post metamorphosis females produce two egg strings. The mean number of eggs in each egg string was 52. Three naupliar and first copepodid stages were obtained in culture while two copepodid stages, cyclopoid and adult specimens were obtained after artificial infection of catfish in aquaria. First stage nauplii were globular in shape and densely filled with yolk. Nauplii lacked a perforation for the mouth and masticatory parts of the appendages, all of which indicate that they do not feed. Body architecture of the first copepodid stage of L. clariae is similar to that of all other copepods in the number and kind of somites: a cephalothorax with five appendages, three thoracic somites, one abdominal somite and furca rami. This seems to be a conserved morphology among the copepods. The three naupliar and three copepodid stages are described and compared to related copepods.

scholarly journals Unravelling anisogamy: egg size and ejaculate size mediate selection on morphology in free-swimming sperm

2016 ◽  
Vol 283 (1834) ◽  
pp. 20160671 ◽  
Author(s):  
Keyne Monro ◽  
Dustin J. Marshall
Keyword(s):  
Egg Size ◽  
Free Swimming ◽  
External Fertilization ◽  
Selection Pressures ◽  
Sperm Density ◽  
Ejaculate Size ◽  
Selection For ◽  
The Stability ◽  
Multicellular Organisms ◽  
Sperm Size

Gamete dimorphism (anisogamy) defines the sexes in most multicellular organisms. Theoretical explanations for its maintenance usually emphasize the size-related selection pressures of sperm competition and zygote survival, assuming that fertilization of all eggs precludes selection for phenotypes that enhance fertility. In external fertilizers, however, fertilization is often incomplete due to sperm limitation, and the risk of polyspermy weakens the advantage of high sperm numbers that is predicted to limit sperm size, allowing alternative selection pressures to target free-swimming sperm. We asked whether egg size and ejaculate size mediate selection on the free-swimming sperm of Galeolaria caespitosa , a marine tubeworm with external fertilization, by comparing relationships between sperm morphology and male fertility across manipulations of egg size and sperm density. Our results suggest that selection pressures exerted by these factors may aid the maintenance of anisogamy in external fertilizers by limiting the adaptive value of larger sperm in the absence of competition. In doing so, our study offers a more complete explanation for the stability of anisogamy across the range of sperm environments typical of this mating system and identifies new potential for the sexes to coevolve via mutual selection pressures exerted by gametes at fertilization.

Field studies on the small Surinam toad, Pipa arrabali, near Manaus, Brazil

1993 ◽  
Vol 14 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Christian O. Buchacher
Keyword(s):  
Larval Stage ◽  
Rainy Season ◽  
Field Studies ◽  
The Other ◽  
Primary Forest ◽  
Free Swimming

AbstractA population of the small Surinam toad, Pipa arrabali, was studied at an isolated pool site in undisturbed primary forest, 70 km north of Manaus, Brazil. During the eleven months of examination, 371 individuals were toe-clipped. The toads preferred more persistent pools where they preyed upon tadpoles of other anurans. If a home pool dried up or a source of food became available in one of the other pools the toads migrated over land for short distances. Of a total of 84 recaptures, 28 (33%) were found in a pool other than the original. P. arrabali bred throughout the entire year, but females with larvae in the dermal pockets on their backs were particularly frequent at the end of the rainy season (April to June). No free swimming larval stage occurs. Depending on the size of the female, between 6 and 16 eggs develop directly into small toads. Snout-vent length at emergence ranges from 10 to 14 mm.

The challenges of asymmetric mating – the influence of male and female size on the reproductive output of Acanthochondria cornuta (Chondracanthidae)

Parasitology ◽  
2016 ◽  
Vol 143 (14) ◽  
pp. 1945-1953
Author(s):  
D. G. FRADE ◽  
S. NOGUEIRA ◽  
M. J. SANTOS ◽  
F. I. CAVALEIRO
Keyword(s):  
Egg Size ◽  
Reproductive Output ◽  
Reproductive Effort ◽  
Parasitic Copepod ◽  
Female Size ◽  
Male Size ◽  
Male And Female ◽  
Four Seasons ◽  
Egg Number ◽  
Potential Impact

SUMMARYThe reproductive strategy of Acanthochondria cornuta, a parasitic copepod with dwarf, hyperparasitic males, is described in detail. The potential impact of male parasitism on the reproductive output was evaluated by determining the size of each sex and the female's fecundity, egg size and total reproductive effort for each pair/trio throughout the four seasons of the year. Marked seasonal differences were observed in female size and reproductive output, suggesting two distinct generations, but no differences were observed for male size. No statistically significant correlations were observed between male size and any measure of reproductive effort, but females with larger males had lower fecundity. A trade-off between egg number and egg size was recorded. Overall, the reproductive effort in A. cornuta seems to be determined mostly by female size, and larger females do not hold smaller males.

Correlations between egg size and dependent variables related to larval stage in Persian sturgeonAcipenser persicus

2009 ◽  
Vol 42 (2) ◽  
pp. 147-155 ◽  
Author(s):  
Rajab Mohammad Nazari ◽  
Mehdi Sohrabnejad ◽  
Mohammad Reza Ghomi ◽  
Maryam Modanloo ◽  
Mahmoudreza Ovissipour ◽  
...  
Keyword(s):  
Larval Stage ◽  
Egg Size ◽  
Dependent Variables

Effect of egg size on incubation time and alevin and fry size in chum salmon (Oncorhynchus keta) and coho salmon (Oncorhynchus kisutch)

1985 ◽  
Vol 63 (4) ◽  
pp. 847-850 ◽  
Author(s):  
T. D. Beacham ◽  
F. C. Withler ◽  
R. B. Morley
Keyword(s):  
Egg Size ◽  
Chum Salmon ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Oncorhynchus Keta ◽  
Free Swimming ◽  
Chum Salmon Oncorhynchus Keta ◽  
Hatching Time ◽  
Significant Difference ◽  
Yolk Absorption

Variability in hatching time, time of exogenous yolk absorption ("button up") of alevins, alevin size, and fry size was investigated with respect to initial egg size for chum salmon (Oncorhynchus keta) and coho salmon (Oncorhynchus kisutch). There was no significant difference with respect to egg size in hatching time of the alevins (stage between hatching and emergence from the redd) or time of exogenous yolk absorption for either species. For both species, alevins hatching from large eggs were longer and had greater amounts of yolk than those hatching from small eggs. Tissue weights of the alevins were not different. The differences in size between these two groups of alevins were maintained throughout the alevin stage and were greater at exogenous yolk absorption than at hatching. Fry (newly emerged, free-swimming young) derived from large eggs had greater tissue weight at exogenous yolk absorption than those derived from small eggs.

Experimental Studies of the Reproductive Behaviour of the Parasitic Copepod Lernaeocera Branchialis (Pennellidae)

1989 ◽  
Vol 69 (2) ◽  
pp. 465-476 ◽  
Author(s):  
Morten Anstensrud
Keyword(s):  
Gadus Morhua ◽  
Experimental Studies ◽  
Reproductive Behaviour ◽  
Parasitic Copepod ◽  
Infective Stage ◽  
Free Swimming ◽  
Frontal Filament ◽  
Gill Cavity ◽  
Merlangius Merlangus ◽  
Early Larval Development

Egg-producing Lernaeocera branchialis (L.) are usually found in the gill cavity of cod (Gadus morhua (L.)) and whiting (Merlangius merlangus (L.)) (Kabata, 1979). The early larval development of the copepod includes two free-swimming nauplius stages followed by the first infective stage, the copepodite (Sproston, 1942). On an intermediate host, usually flounder (Platichthys flesus (L.)), the copepodite moults into a chalimus larva which is attached by its frontal filament to the gill tips of its host. After four successive chalimus stages, the parasite reaches maturity and copulation occurs on the flatfish host.

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