scholarly journals Reproductive biology of the deep-sea polychaete Gorgoniapolynoe caeciliae (Polynoidae), a commensal species associated with octocorals

2005 ◽  
Vol 85 (6) ◽  
pp. 1425-1433 ◽  
Author(s):  
K.J. Eckelbarger ◽  
L. Watling ◽  
Heidi Fournier
Keyword(s):  
New England ◽  
Blood Vessels ◽  
Reproductive Biology ◽  
Deep Sea ◽  
Indirect Evidence ◽  
Maximum Diameter ◽  
Dioecious Species ◽  
Planktotrophic Larva ◽  
Commensal Species ◽  
Spherical Head

Some aspects of the reproductive biology of the polychaete Gorgoniapolynoe caeciliae have been described for the first time. Gorgoniapolynoe caeciliae is a deep-sea commensal species associated with Candidella imbricata, an octocoral that populates the New England Seamount chain. Gorgoniapolynoe caeciliae is a dioecious species with an equal sex ratio and fertile segments throughout most of the adult body. The gonads of both sexes are associated with genital blood vessels emerging from the posterior surface of most intersegmental septa. In the female, oogenesis is intraovarian with oocytes being retained within the ovary until vitellogenesis is completed. The largest female examined contained over 3000 eggs with a maximum diameter of 80–90 μm. In the male, the testes are repeated in numerous segments and consist of small clusters of spermatogonia, spermatocytes, and early spermatids associated with the walls of the genital blood vessels. Early spermatids are shed into the coelom where they complete differentiation into mature ect-aquasperm with a spherical head (4 μm), a small cap-like acrosome, and a short mid-piece with four mitochondria. Indirect evidence suggests that this species is an annual breeder that releases its gametes into seawater and produces a planktotrophic larva following fertilization. The reproductive biology of G. caeciliae is consistent with that of most other polynoids including many shallow water species suggesting that phylogenetic history strongly shapes its biology.

The Reproductive Biology of Ophiacantha Bidentata (Echinodermata: Ophiuroidea) From The Rockall Trough

1982 ◽  
Vol 62 (1) ◽  
pp. 45-55 ◽  
Author(s):  
P. A. Tyler ◽  
J. D. Gage
Keyword(s):  
Reproductive Biology ◽  
Deep Water ◽  
Larval Stage ◽  
North Pacific ◽  
Deep Sea ◽  
Direct Development ◽  
The Arctic ◽  
Shallow Waters ◽  
Arctic Seas ◽  
Rockall Trough

INTRODUCTIONOphiacantha bidentata (Retzius) is a widespread arctic-boreal ophiuroid with a circumpolar distribution in the shallow waters of the Arctic seas and penetrating into the deep sea of the.North Atlantic and North Pacific (Mortensen, 1927, 1933a; D'yakonov, 1954). Early observations of this species were confined to defining zoogeo-graphical and taxonomic criteria including the separation of deep water specimens as the variety fraterna (Farran, 1912; Grieg, 1921; Mortensen, 1933a). Mortensen (1910) and Thorson (1936, pp. 18–26) noted the large eggs (o.8 mm diameter) in specimens from Greenland and Thorson (1936) proposed that this species had ‘big eggs rich in yolk, shed directly into the sea. Much reduced larval stage or direct development’. This evidence is supported by observations of O. bidentata from the White and Barents Seas (Semenova, Mileikovsky & Nesis, 1964; Kaufman, 1974)..

scholarly journals A review of the genus Iridogorgia (Octocorallia: Chrysogorgiidae) and its relatives, chiefly from the North Atlantic Ocean

2007 ◽  
Vol 87 (2) ◽  
pp. 393-402 ◽  
Author(s):  
Les Watling
Keyword(s):  
New Species ◽  
Atlantic Ocean ◽  
New England ◽  
North Atlantic ◽  
Deep Sea ◽  
New Genus ◽  
Growth Form ◽  
North Atlantic Ocean ◽  
The North ◽  
The North Atlantic

Exploration of the New England and Corner Rise Seamounts produced four new species of chrysogorgiid octocorals with the spiral iridogorgiid growth form. Three species are described as new in the genus Iridogorgia and one is described in the new genus Rhodaniridogorgia. Both genera have representatives in the Atlantic and Pacific Oceans. Iridogorgia magnispiralis sp. nov., is one of the largest octocorals encountered in the deep sea and seems to be widespread in the Atlantic.

Reproductive biology of two deep-water sharks from the British Isles, Centroscymnus coelolepis and Centrophorus squamosus (Chondrichthyes: Squalidae)

1999 ◽  
Vol 79 (5) ◽  
pp. 923-931 ◽  
Author(s):  
Marine Girard ◽  
Marie-Henriette Du Buit
Keyword(s):  
Reproductive Biology ◽  
Deep Sea ◽  
Average Length ◽  
Sexual Stage ◽  
British Isles ◽  
The West ◽  
Pregnant Females ◽  
Stage Of Development ◽  
First Maturity ◽  
Size At First Maturity

The reproductive biology of two aplacental viviparous deep sea sharks, Centroscymnus coelolepis and Centrophorus squamosus has been studied from 1735 and 675 specimens respectively, collected with bottom trawls between 600 and 1400 m depth off the west coast of the British Isles. A macroscopic maturity scale indicates that for both species, size at first maturity is greater in females than in males. In Centroscymnus coelolepis, genital maturity occurs at an average length of ∼86 cm for males and ∼102 cm for females. In Centrophorus squamosus, males are mature near 98 cm and females near 124 cm total length (TL). Smallest juveniles of both species are absent from catches: no specimens of Centroscymnus coelolepis shorter than 58 cm, nor specimens of Centrophorus squamosus shorter than 84 cm have been recorded. Ovarian fecundity is higher in Centroscymnus coelolepis than in Centrophorus squamosus. A maternal supply has been demonstrated for Centroscymnus coelolepis. Litter size has been estimated only in C. coelolepis because no pregnant females of Centrophorus squamosus were recovered. A dwarf embryo and a pair of twins have been observed. Segregation by sexual stage of development shows that immatures are generally found at greater depths than adults.

The reproductive biology of deep-sea forcipulate seastars (Asteroidea: Echinodermata) from the N.E. Atlantic Ocean

1984 ◽  
Vol 64 (3) ◽  
pp. 587-601 ◽  
Author(s):  
P. A. Tyler ◽  
S. L. Pain ◽  
J. D. Gage ◽  
D. S. M. Billett
Keyword(s):  
Atlantic Ocean ◽  
Reproductive Biology ◽  
Deep Sea ◽  
Egg Size ◽  
Dorsal Surface ◽  
Oocyte Diameter ◽  
Interspecific Variations ◽  
Egg Diameter

Samples of the deep-sea forcipulate seastars Brisinga endecacnemos, Brisingella coronata, Freyella spinosa and Zoroaster fulgens have been collected at a number of stations in the N.E. Atlantic. Examination of their reproductive biology suggests subtle interspecific variations in their gametogenic cycles. The gonads of Brisinga endecacnemos are serially arranged under the dorsal arm surface, each cluster of gonad tubules having its own gonopore. In the closely related Brisingella coronata each gonad consists of up to 12 elongate tubules opening at a single gonopore at the dorsal surface. In both species the maximum egg diameter is about 1250 μm and fecundity may be up to 60000 eggs per individual. It appears that the eggs in Brisinga endecacnemos are produced in clusters whilst those of Brisingella coronata are produced continuously. InFreyella spinosa the gonad consists of a small tubular sac analogous to a single tubule of Brisinga endecacnemos. Maximum fecundity is only 2500 eggs per individual, and the maximum egg size is 1250 μm. In all three species eggs that are not spawned undergo internal oocyte degeneration. The gonads of Zoroaster fulgens show the typical asteroid configuration of two at the base of each arm, one either side of the ambulacrum. The maximum oocyte diameter is 950 μm. There is some evidence that there may be a seasonality of reproduction in this species. In all four species examined the large egg size and relatively low fecundity suggest direct demersal development with the subtle variations in their reproductive biology reflecting slightly different breeding habits.

Seasonality and selectivity in the feeding ecology and reproductive biology of deep-sea bathyal holothurians

2003 ◽  
Vol 59 (4) ◽  
pp. 381-407 ◽  
Author(s):  
Ian R Hudson ◽  
Benjamin D Wigham ◽  
David S.M Billett ◽  
Paul A Tyler
Keyword(s):  
Reproductive Biology ◽  
Feeding Ecology ◽  
Deep Sea

scholarly journals Reproductive Biology in Northern Prickly Ash

2018 ◽  
Vol 143 (1) ◽  
pp. 72-83
Author(s):  
David A. Munter ◽  
James J. Luby ◽  
Neil O. Anderson
Keyword(s):  
Reproductive Biology ◽  
Reproductive Strategies ◽  
Economic Importance ◽  
Reproductive Barriers ◽  
Pollen Stainability ◽  
Dioecious Species ◽  
Zanthoxylum Americanum ◽  
The Mean ◽  
Northern Forests ◽  
Autonomous Apomixis

Zanthoxylum americanum is a common understory species in the northern forests of Minnesota and surrounding regions. It has potential economic importance for its citrus fragrance, pharmacological or insecticidal properties, and produces peppercorns similar to those of the related Zanthoxylum species. Zanthoxylum americanum is a dioecious species but has been reported to have aberrant flowers with autonomous apomixis instead of other potential reproductive barriers. The reproductive biology of Zanthoxylum americanum was investigated in two native Minnesota populations. Determinations of male fertility, whether autonomous apomixis was the predominant floral reproductive mechanism, the presence of seedless fruit (parthenocarpy/stenospermocarpy), and the occurrence of hermaphrodism were made over 2 years. Sex ratios (female:male plants) within each population differed. The mean pollen stainability was 95.8% ± 0.3% (fresh) and 78.6% ± 1.1% (stored 18 months). Parthenocarpy did not occur in either population. Autonomous apomixis was not the primary floral reproductive mechanism. Stenospermocarpy (seedlessness) occurred in 13% of the female fruit clusters. Although commonly described as being dioecious, two additional reproductive strategies were identified: 1) plants with functional protandrous flowers with rudimentary pistils and 2) hermaphroditic flowers with fully functional pistils (protogynous) and anthers. As many as 10% to 30% of the male plants bore at least one fruit/plant each year. One clonal stand had both hermaphroditic and functionally staminate flowers on the same plant. Two evolutionary pathways to dioecy in Z. americanum are proposed.

The Reproductive Biology of the Deep-Sea Asteroid Bathybiaster Vexillifer

1982 ◽  
Vol 62 (1) ◽  
pp. 57-69 ◽  
Author(s):  
P. A. Tyler ◽  
S. L. Pain ◽  
J. D. Gage
Keyword(s):  
Shallow Water ◽  
Reproductive Biology ◽  
Deep Sea ◽  
Reproductive Strategies ◽  
Ecological Niches ◽  
Physico Chemical ◽  
Males And Females ◽  
Planktotrophic Larvae ◽  
Shallow Water Species ◽  
Water Species

INTRODUCTIONThe reproductive biology of asteroids from a wide variety of ecological niches has been examined (Farmanfarmaian et al. 1958; Cognetti & Delavault, i962;Pearse, 1965; Chia, 1968; Crump, 1971; Jangoux & Vloebergh, 1973; Worley, Franz & Hendler, 1977; Barker, 1979; Shick, Taylor & Lamb, 1981). Most of the species within this class appear to show some degree of seasonal reproductive synchrony with very few species showing aseasonal reproduction (Shick et al. 1981). Although the seasonally reproducing asteroids show a wide variety of reproductive strategies, from planktotrophic larvae to direct development, they all occur in relatively shallow water and are thus subject to the seasonal fluctuations of the physico-chemical environment. Only two shallow-water species, Ctenodiscus crispatus (Shick et al. 1981) and Patiriella exigua (Lawson-Kerr & Anderson, 1978), have aseasonal reproduction in both males and females. However, the deep sea is the only major environment in the world's ocean for which we have no data for the reproductive cycle of asteroids.

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