Partial Protandric Hermaphroditism in the Burrowing Crayfish Parastacus nicoleti (Philippi, 1882) (Decapoda: Parastacidae)

1995 ◽  
Vol 15 (4) ◽  
pp. 720 ◽  
Author(s):  
Erich H. Rudolph
Keyword(s):  
Protandric Hermaphroditism

Ultrastructural characteristics of spermatogenesis in three species of deep-sea hydrothermal vent mytilids

1997 ◽  
Vol 75 (2) ◽  
pp. 308-316 ◽  
Author(s):  
Marcel Le Pennec ◽  
Peter G. Beninger
Keyword(s):  
Deep Sea ◽  
Hydrothermal Vent ◽  
The North ◽  
Male Gametes ◽  
Bathymodiolus Thermophilus ◽  
Nutritional Biology ◽  
Protandric Hermaphroditism ◽  
Mid Atlantic Ridge ◽  
Ultrastructural Characteristics ◽  
Species Specific

To enhance our understanding of the reproductive biology of deep-sea hydrothermal vent mytilids, the histology of the male gonad and the ultrastructure of its gametes were studied in Bathymodiolus thermophilus, B. puteoserpentis, and B. elongatus. Specimens of B. thermophilus were collected at the 13°N site on the East Pacific ridge, while B. puteoserpentis were sampled from the Snake Pit site of the mid-Atlantic ridge and B. elongatus were obtained from the North Fiji Basin. Gonad histology conformed to the typical bivalve profile; the differences in the proportions of acinal and interacinal tissue, as well as differences in acinal fullness in B. puteoserpentis, indicate that gametogenesis is discontinuous in these deep-sea mytilids. Evidence of protandric hermaphroditism was observed in B. elongatus, which exhibited acini containing both maturing and residual male gametes and immature oocytes. The ultrastructural characteristics of the male gametes conform to those described for littoral bivalve species, and the spermatozoon is of the primitive type. No species-specific differences in spermatozoon ultrastructure were discerned. No evidence of bacterial inclusions was found in either the gametes or the associated gonad cells in any of the species examined. The male gametes are thus probably not vectors for the endosymbiotic bacteria that characterize the nutritional biology of the adults in this genus.

Direct Observation of Sex Change in the Patellacean Limpet Lottia Gigantea

1982 ◽  
Vol 62 (3) ◽  
pp. 737-738 ◽  
Author(s):  
William G. Wright ◽  
David R. Lindberg
Keyword(s):  
Sexual Dimorphism ◽  
Differential Growth ◽  
External Fertilization ◽  
Size Classes ◽  
Direct Observations ◽  
Protandric Hermaphroditism ◽  
Intermediate Size ◽  
Lottia Gigantea ◽  
Male To Female ◽  
Simultaneous Hermaphrodites

Protandric hermaphroditism, the sequential change from male to female, has been reported in several superfamilies of prosobranch gastropods including the Fissurellacea, Patellacea, Calyptraeacea, and Eulimacea (Webber, 1977). It is most common in members of the Calyptraeacea and the Patellacea. In the Calyptraeacea changes in sex are readily followed by observing copulative structures (Coe, 1944). Because patellacean limpets are predominantly broadcast spawners with external fertilization, external characters that can be used to determine the sex of individuals are rare. Hence, previous to this report the occurrence of protandry in most patellacean limpets has been based primarily on sexual dimorphism in size; the smaller size classes being made up of male individuals and the larger size classes of female individuals (Willcox, 1898; Orton, 1920, 1928; Orton, Southward & Dodd, 1956; Dodd, 1956; Branch, 1974). However, given this type of data it is often difficult to assess whether the observed sexual dimorphism is indicative of protandry or merely a result of differential growth and/or survival. The presence of simultaneous hermaphrodites in the intermediate size classes, as evidence of protandry is of limited value because simultaneous hermaphrodites occur sporadically in patellaceans that do not show a sexual dimorphism in size (Dodd, 1956; Branch, 1974). The only unambiguous way of proving the existance of protandry in patellacean limpets is the direct monitoring of gonadal changes in individuals through time. We report here the first direct observations of protandric hermaphroditism in a patellacean limpet.Lottia gigantea Sowerby, 1834 is a large (100 + mm), territorial, intertidal limpet that ranges from northern California to central Baja California, Mexico (Stimson, 1970).

Development of external sexual characters of deep sea Bythocaris shrimps (Crustacea: Decapoda: Hippolytidae)

2006 ◽  
Vol 86 (2) ◽  
pp. 349-359 ◽  
Author(s):  
Vassily I. Sokolov ◽  
Vassily A. Spiridonov
Keyword(s):  
Life History ◽  
North Atlantic ◽  
Deep Sea ◽  
Sex Change ◽  
Number Of Species ◽  
Appendix Masculina ◽  
Protandric Hermaphroditism ◽  
Specific Variation

The development of sex-specific characters is described for the deep sea North Atlantic/Arctic shrimp genus Bythocaris. A number of species were examined in the collections of Russian institutions including B. biruli, B. curvirostris, B. irene, B. leucopis and B. payeri. The pattern of size-specific variation in the masculine characters, i.e. the development of the modified appendix interna on the endopodite of the first pleopod and the appendix masculina do not indicate the presence of sex change (protandric hermaphroditism) in the life history.

Early gonadal differentiation in the Mexican snook Centropomus poeyi (Centropomidae, Perciformes, Teleostei) suggests protandric hermaphroditism

2018 ◽  
Vol 51 (6) ◽  
pp. 327-345 ◽  
Author(s):  
Juan Manuel Vidal-López ◽  
Wilfrido Miguel Contreras-Sánchez ◽  
Aarón Torres-Martínez ◽  
Arlette Amalia Hernández-Franyutti ◽  
María Del Carmen-Aranzábal Uribe
Keyword(s):  
Gonadal Differentiation ◽  
Protandric Hermaphroditism

Studies of a benthic time series: reproductive biology of benthic invertebrates in the Rockall Trough

1986 ◽  
Vol 88 ◽  
pp. 175-190 ◽  
Author(s):  
P. A. Tyler
Keyword(s):  
Time Series ◽  
Reproductive Biology ◽  
Deep Sea ◽  
Egg Production ◽  
Single Case ◽  
Individual Species ◽  
Reproductive Pattern ◽  
Reproductive Patterns ◽  
Rockall Trough ◽  
Protandric Hermaphroditism

SynopsisThe reproductive biology of a wide variety of deep-sea echinoderms from the northeast Atlantic has been examined. Time series samples of asteroids, ophiuroids, echinoids and holothurians are available from Station “M” and the Scottish Marine Biological Association's Permanent Station in the Rockall Trough and from opportunistic sampling in other areas of the northern Rockall Trough. Examination of these time series samples has established three main reproductive patterns in these taxa and one example of protandric hermaphroditism. The dominant reproductive pattern is the aperiodic production of relatively few large eggs usually in excess of 600μm diameter. Although the oogenic pattern is similar in most of these species, the follicle cell distribution and breakdown of relict oocytes vary considerably, particularly at family level. A second reproductive pattern is the production of numerous small eggs c. 100μm diameter, indicative of planktotrophic development. The five species exhibiting this pattern show intra- and interspecific synchrony of egg production with a proliferation of young oocytes in February to April of each year, vitellogenesis during summer and autumn and a synchronous spawnout in January–April of each year. In the apparent constant conditions of the deep sea, this synchrony of reproduction is related to the rapid descent of surface primary production. Two rarer reproductive patterns observed are the production of intermediate sized eggs (c. 300–400μm diameter) suggesting the formation of a lecithotrophic larva, and lastly a single case of protandric hermaphroditism, and the subsequent production of a large egg. In none of the species examined have we found any evidence of brooding. The variation in the reproductive pattern of individual species is discussed in relation to the constancy of the physico-chemical environment of the deep-sea.

scholarly journals On the occurrence of protandric hermaphroditism in the mollusc Crepidula fornicata

1909 ◽  
Vol 81 (550) ◽  
pp. 468-484 ◽  
Keyword(s):  
East Coast ◽  
Anterior Part ◽  
The Other ◽  
Front Edge ◽  
Crepidula Fornicata ◽  
Protandric Hermaphroditism ◽  
Blackwater Rivers ◽  
A Chain ◽  
The One ◽  
The Right

Crepidula fornicata is a streptoneurous Gastropod belonging to the Calyptræidæ, a family of the Tænioglossa. It was first introduced into England from America about 1880 (1), when it was imported with American oysters. In America it is found on the east coast from Labrador to Florida, but in England so far as is known, it is confined to the Essex and Lincolnshire coasts, occurring, however, in abundance in shallow water in the neighbourhood of the mouths of the Crouch and Blackwater rivers. The conditions on the Essex coast seem to be highly favourable for its growth and propagation; indeed, so favourable, that within five or six years it has over-run the oyster beds at West Mersea. By attaching themselves very strongly to oyster-shells they cause the oyster fisherman much trouble, and it may be remarked, by competing for food and oxygen with the oysters may become a cause of much more serious trouble in the future. To obtain food the animals raise the anterior part of their shell and extending the head to the front edge of the shell, move it slowly from side to side: at times the whole shell may be similarly turned slowly round to the one side or the other. Crepidula fornicata is sedentary for the greater part of its life. It forms "chains," as Prof. Conklin calls them, by the curious habit the individuals have of fixing themselves in linear series one on the top of another as in fig. 1. Chains of as many as 12 individuals have been found. Viewed as a whole, a chain is seen to form a spiral of about half a trun, bending over to the right.

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