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Paul C Southgate - One of the best experts on this subject based on the ideXlab platform.
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Genome-wide comparisons reveal evidence for a species complex in the black-lip pearl oyster Pinctada margaritifera (Bivalvia: Pteriidae)
Scientific Reports, 2018Co-Authors: Paul C Southgate, Dean R Jerry, Kyall R. ZengerAbstract:Evolutionary relationships in the black-lip pearl oyster Pinctada margaritifera which is highly valued for pearl production remain poorly understood. This species possesses an 18,000 km Indo-Pacific natural distribution, and its current description includes six subspecies defined exclusively on morphological characters. To evaluate its taxonomic identity using molecular data, 14 populations in both the Indian and Pacific Oceans (n = 69), and the congeneric taxa P . maxima and P . mazatlanica (n = 29 and n = 10, respectively) were sampled. Phylogenomic reconstruction was carried out using both 8,308 genome-wide SNPs and 10,000 dominant loci (DArTseq PAVs). Reconstructions using neighbour-joining (Nei’s 1972 distances), maximum likelihood and Bayesian approaches all indicate that the taxonomy of P . margaritifera is quite complex, with distinct evolutionary significant units (ESUs) identified within Tanzanian and Iranian populations. Contrastingly, phylogenies generated for Pacific Ocean oysters resolved a large monophyletic clade, suggesting little support for two current morphological subspecies classifications. Furthermore, P . mazatlanica formed a basal clade closest to French Polynesian P . margaritifera , suggesting it may be conspecific. Collectively, these findings provide evidence that P . margaritifera comprises a species complex, perhaps as a result of population fragmentation and increased divergence at range limits.
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reproductive cycle of the winged pearl oyster pteria penguin roding 1793 Pteriidae in north eastern australia
Invertebrate Reproduction & Development, 2012Co-Authors: Michael Milione, Paul C SouthgateAbstract:The spawning cycle of the winged pearl oyster, Pteria penguin, was studied at Orpheus Island, north-eastern Queensland to observe seasonal changes in gonad development, mean oocyte diameter and sex ratio over time. A total of 201 oysters were collected over 10 sampling periods, approximately every 5–6 weeks (mean = 20 oysters/sample). Histological analysis of gonads showed that spawning activity occurred mainly through the austral mid-spring to late summer (November to March), when mean monthly water temperature ranged between 27.5°C and 29.4°C. There was a primary spawning peak at the beginning of the spawning season in December, followed by a secondary peak in March. Mean oocyte diameter (µm) was highest during the warmer months, ranging from 31.2 ± 2.4 in November to 36.2 ± 3.2 in March, and sex ratio analysis showed the percentage of females in the population also peaked between 30% and 50% during this period.
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embryonic and larval development of pteria penguin roding 1798 bivalvia Pteriidae
Journal of Molluscan Studies, 2012Co-Authors: Matthew Wassnig, Paul C SouthgateAbstract:This study describes the processes of embryogenesis, shell formation and larval development of the winged pearl oyster, Pteria penguin. Broodstock were induced to spawn using the standard method of thermal stimulation and fertilized eggs were incubated at a density of 50 ml−1 and a temperature of 27 ± 1°C. After an incubation period of 24 h, shelled larvae were stocked at 3 ml−1 and fed a mixed microalgae diet until reaching settlement age. Embryos and larvae were sampled periodically for examination by scanning electron microscope. The resulting high-resolution images were used to record the timing of developmental stages including the first cleavage (1 h postfertilization, hpf), morula (2.5 hpf), blastula (4.5 hpf), gastrula (5.5 > hpf), trochophore (7 > hpf), D-stage (20–22 hpf), prodissoconch II (3–6 days posthatching, dph), umbone (10–12 dph) and pediveliger (22 dph). Comparison with other oviparous oyster species revealed a similar sequence of key events, with differences occurring in the timing of developmental stages, shell structure and shell shape. This study is the first to describe early shell formation for a species belonging to the family Pteriidae. Shell development begins with formation a shell-field invagination (sfi) at the dorsoposterior end of the embryo (7 hpf), indicating the creation of a shell gland. The sfi stretches laterally to create a deep crevice (9 hpf) before eventually everting to form a flat central hinge linking the two expanding shell valves (12 hpf).
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Sexual development, sex ratio and morphometrics of Pteria penguin (Bivalvia: Pteriidae), in North-Eastern Australia
Molluscan Research, 2011Co-Authors: Michael Milione, Pedro E Saucedo, Paul C SouthgateAbstract:Pteria penguin were collected at Orpheus Island, north-eastern Queensland to observe sexual development, sex ratio and changes in morphometric relationships during growth. P. penguin are protandrous hermaphrodites, with all sexually mature oysters below 88.8 mm dorso-ventral height (DVH) being males. Evidence of male primary gonad development was seen in oysters with a DVH of ≥33.9 mm. Sexual maturity of males was first seen in oysters at ≥56.0 mm DVH, but was common in oysters at ≥70.0 mm DVH. Mean female size was 150.1 (±3.6) mm DVH, and mean male size was 111.3 (±2.2) mm DVH. In oysters 180 mm DVH. Significant linear correlations were found between anterior-posterior length of the shell (APL) and DVH (r2 = 0.97, p
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sexual development sex ratio and morphometrics of pteria penguin bivalvia Pteriidae in north eastern australia
Molluscan Research, 2011Co-Authors: Michael Milione, Pedro E Saucedo, Paul C SouthgateAbstract:Pteria penguin were collected at Orpheus Island, north-eastern Queensland to observe sexual development, sex ratio and changes in morphometric relationships during growth. P. penguin are protandrous hermaphrodites, with all sexually mature oysters below 88.8 mm dorso-ventral height (DVH) being males. Evidence of male primary gonad development was seen in oysters with a DVH of ≥33.9 mm. Sexual maturity of males was first seen in oysters at ≥56.0 mm DVH, but was common in oysters at ≥70.0 mm DVH. Mean female size was 150.1 (±3.6) mm DVH, and mean male size was 111.3 (±2.2) mm DVH. In oysters 180 mm DVH. Significant linear correlations were found between anterior-posterior length of the shell (APL) and DVH (r2 = 0.97, p <0.001) and between shell thickness (ST) and DVH (r2 = 0.95, p <0.001), and a curvilinear relationship was recorded between adductor muscle weight (AW) and DVH (r2 = 0.93, p <0.001). These findings have industry applications for collection of juvenile stock, spawning induction procedures and determining optimal shell size for pearl nucleus implanting.
Mario Monteforte - One of the best experts on this subject based on the ideXlab platform.
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differential gonadal development of grafted and ungrafted specimens of the calafia mother of pearl oyster pinctada mazatlanica bivalvia Pteriidae
Invertebrate Reproduction & Development, 2001Co-Authors: Pedro E Saucedo, Horacio Bervera, Humberto Villarreal, Ilie S. Racotta, Mario MonteforteAbstract:Summary The present work deals with the existence of differential gonadal development between grafted and ungrafted specimens of the pearl oyster, Pinctada mazatlanica. Oysters were collected as spat and extensively cultured until they were suitable for pearl formation. A mantle allograft was placed within the gonadal tissue and the treated oysters were maintained under the same culture conditions as untreated oysters. After a year of Keshi pearl formation, samples of gonadal tissue, digestive gland, and muscle were excised from each oyster and used for histological and biochemical analyses. The histological examination of gonads was supported with measurements of the oocyte frequency and diameter and the use gonadic and muscle performance indices. For biochemical analyses, the concentration of carbohydrates, proteins, lipids, and triacylglycerides was studied. A two-way ANOVA was applied for differences in the oocyte diameter, index values, and biochemical composition of specimens over time and experimen...
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spat collection studies on pearl oysters pinctada mazatlanica and pteria sterna bivalvia Pteriidae in bahia de la paz south baja california mexico
Hydrobiologia, 1994Co-Authors: Mario Monteforte, Alejandra GarciagascaAbstract:The present work deals with the temporal and bathymetrical variations of the epifaunal community associated with two species of pearl oysters (Pinctada mazatlanica and Pteria sterna) during a seed collecting season from June to November 1989. A total of 63 items (species, genera and/or families) were recorded; their variations in presence and abundance were followed during three periods (June–July, August–September and October–November). The collectors were examined for different immersion times (2, 4, 6 and 8 weeks) for each period. Community structure was compared through the Brillouin Index, the Morisita Index and the Importance Value.
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Spat collection studies on pearl oysters Pinctada mazatlanica and Pteria sterna (Bivalvia, Pteriidae) in Bahia de La Paz, South Baja California, Mexico
Hydrobiologia, 1994Co-Authors: Mario Monteforte, Alejandra Garcia-gascaAbstract:The present work deals with the temporal and bathymetrical variations of the epifaunal community associated with two species of pearl oysters ( Pinctada mazatlanica and Pteria sterna ) during a seed collecting season from June to November 1989. A total of 63 items (species, genera and/or families) were recorded; their variations in presence and abundance were followed during three periods (June–July, August–September and October–November). The collectors were examined for different immersion times (2, 4, 6 and 8 weeks) for each period. Community structure was compared through the Brillouin Index, the Morisita Index and the Importance Value. We define the chronology of spatfall for both species of pearl oysters and their bathymetrical distribution. Relationships between these species and the epifaunal community present into the collectors were analysed, searching for possible noxious effects on the survival of juvenile pearl oysters, and identifying index species related with their spatfall. A strategy for starting massive seed collection of both species is established, particularly for P. mazatlanica .
Alejandra Garcia-gasca - One of the best experts on this subject based on the ideXlab platform.
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Spat collection studies on pearl oysters Pinctada mazatlanica and Pteria sterna (Bivalvia, Pteriidae) in Bahia de La Paz, South Baja California, Mexico
Hydrobiologia, 1994Co-Authors: Mario Monteforte, Alejandra Garcia-gascaAbstract:The present work deals with the temporal and bathymetrical variations of the epifaunal community associated with two species of pearl oysters ( Pinctada mazatlanica and Pteria sterna ) during a seed collecting season from June to November 1989. A total of 63 items (species, genera and/or families) were recorded; their variations in presence and abundance were followed during three periods (June–July, August–September and October–November). The collectors were examined for different immersion times (2, 4, 6 and 8 weeks) for each period. Community structure was compared through the Brillouin Index, the Morisita Index and the Importance Value. We define the chronology of spatfall for both species of pearl oysters and their bathymetrical distribution. Relationships between these species and the epifaunal community present into the collectors were analysed, searching for possible noxious effects on the survival of juvenile pearl oysters, and identifying index species related with their spatfall. A strategy for starting massive seed collection of both species is established, particularly for P. mazatlanica .
Alejandra Garciagasca - One of the best experts on this subject based on the ideXlab platform.
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spat collection studies on pearl oysters pinctada mazatlanica and pteria sterna bivalvia Pteriidae in bahia de la paz south baja california mexico
Hydrobiologia, 1994Co-Authors: Mario Monteforte, Alejandra GarciagascaAbstract:The present work deals with the temporal and bathymetrical variations of the epifaunal community associated with two species of pearl oysters (Pinctada mazatlanica and Pteria sterna) during a seed collecting season from June to November 1989. A total of 63 items (species, genera and/or families) were recorded; their variations in presence and abundance were followed during three periods (June–July, August–September and October–November). The collectors were examined for different immersion times (2, 4, 6 and 8 weeks) for each period. Community structure was compared through the Brillouin Index, the Morisita Index and the Importance Value.
Dean R Jerry - One of the best experts on this subject based on the ideXlab platform.
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Genome-wide comparisons reveal evidence for a species complex in the black-lip pearl oyster Pinctada margaritifera (Bivalvia: Pteriidae)
Scientific Reports, 2018Co-Authors: Paul C Southgate, Dean R Jerry, Kyall R. ZengerAbstract:Evolutionary relationships in the black-lip pearl oyster Pinctada margaritifera which is highly valued for pearl production remain poorly understood. This species possesses an 18,000 km Indo-Pacific natural distribution, and its current description includes six subspecies defined exclusively on morphological characters. To evaluate its taxonomic identity using molecular data, 14 populations in both the Indian and Pacific Oceans (n = 69), and the congeneric taxa P . maxima and P . mazatlanica (n = 29 and n = 10, respectively) were sampled. Phylogenomic reconstruction was carried out using both 8,308 genome-wide SNPs and 10,000 dominant loci (DArTseq PAVs). Reconstructions using neighbour-joining (Nei’s 1972 distances), maximum likelihood and Bayesian approaches all indicate that the taxonomy of P . margaritifera is quite complex, with distinct evolutionary significant units (ESUs) identified within Tanzanian and Iranian populations. Contrastingly, phylogenies generated for Pacific Ocean oysters resolved a large monophyletic clade, suggesting little support for two current morphological subspecies classifications. Furthermore, P . mazatlanica formed a basal clade closest to French Polynesian P . margaritifera , suggesting it may be conspecific. Collectively, these findings provide evidence that P . margaritifera comprises a species complex, perhaps as a result of population fragmentation and increased divergence at range limits.
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effects of cryoprotectant agents and freezing protocol on motility of black lip pearl oyster pinctada margaritifera l spermatozoa
Cryobiology, 2007Co-Authors: Hector Acostasalmon, Dean R Jerry, Paul C SouthgateAbstract:Gamete cryopreservation techniques have been applied to several bivalve mollusc species. However, research activity in this area has primarily focused on cryopreserving gametes from edible oysters (Ostreiidae). Few studies have examined the effect of cryoprotectants and freezing protocols in the preservation of spermatozoa from cultured pearl oysters (Pteriidae). Pearl oyster producers are increasingly looking towards the development of improved family lines and, as a consequence, the ability to cryopreserve gametes would bring about significant benefits to the cultured pearl industry. In response to this need, we evaluated the effect of three cryoprotectant additives (CPA) on motility of spermatozoa from the black-lip pearl oyster, Pinctada margaritifera. These additives have previously been used to cryopreserve gametes of other bivalve species. The following CPA mixtures were evaluated: (1) 0.45 M trehalose and 0, 0.64, 1.02 and 1.53 M dimethyl sulfoxide (Me2SO); (2) 0.2 M glucose and 2 M Me2SO and (3) 1.31 M propylene glycol (PG). The effects of four different freezing protocols on motility of P. margaritifera spermatozoa were also evaluated (slow, medium, medium-rapid and rapid cooling). This study showed that total motility was best retained when spermatozoa were cryopreserved in 0.45 M trehalose and 0, 0.64, 1.02 or 1.53 M Me2SO and frozen using slow to medium-rapid cooling rates (2.1–5.2 °C min−1). Rapid freezing through direct plunging of spermatozoa into liquid nitrogen resulted in the lowest overall retention of motility regardless of the CPA additive; however, CPA mixture also influenced retention of motility, with 0.2 M glucose in 2 M Me2SO and 1.31 M PG retaining the lowest levels of motility for the CPAs evaluated.
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Development and characterization of six new microsatellite markers for the silver-or gold-lipped pearl oyster, Pinctada maxima (Pteriidae)
Molecular Ecology Notes, 2006Co-Authors: Brad S. Evans, Jens Knauer, Joseph J. Taylor, Dean R JerryAbstract:Six di-, tri- and tetranucleotide microsatellite loci were developed for the silver- or gold-lipped pearl oyster Pinctada maxima using a linker-ligated, magnetic bead enrichment protocol. Based on a minimum of 134 Indonesian pearl oyster samples, number of alleles and observed heterozygosity at each locus ranged from six to 17 alleles and from 0.172 to 0.813 (mean = 0.448), respectively. Mean polymorphic information content for the six loci was 0.562. These loci should be very useful in DNA parentage analyses and population differentiation of P. maxima in Australia and Indonesia.
