scholarly journals Mexican dancer in Ecuador: molecular confirmation, embryology and planktotrophy in the sea slug Elysia diomedea

2020 ◽  
Vol 52 ◽  
Author(s):  
Lola Moreano-Arrobo ◽  
Oscar D. Pérez ◽  
Federico D. Brown ◽  
Fernanda X. Oyarzún ◽  
Cristian B. Canales-Aguirre
Keyword(s):  
Genetic Information ◽  
Ex Situ ◽  
Adult Size ◽  
Mtdna Sequences ◽  
Cell Stage ◽  
Egg Capsules ◽  
Northeast Pacific ◽  
Morphological Differences ◽  
General Aspects ◽  
Veliger Larvae

Elysia diomedea varies in adult size and color across its geographical distribution in Ecuador. Because of morphological variation and the absence of genetic information for this species in Ecuador, we analyzed mtDNA sequences in three populations (Ballenita, La Cabuya, and Mompiche) and confirmed that (1) individuals from the three locations belonged to E. diomedea and (2) that there was no population structure that could explain their morphological differences. Next, we analyzed general aspects about the reproductive biology and embryology of this species. Live slugs from the Ballenita population were maintained and reproduced ex situ. Egg ribbons and embryos were fixed and observed by brightfield and confocal microscopy. We observed a single embryo per capsule, 98 embryos per mm2 of egg ribbon, and compared the cleavage pattern of this species to other heterobranchs and spiralians. E. diomedea early development was characterized by a slight unequal first cleavage, occurrence of a 3-cell stage in the second cleavage, and the formation of an enlarged second quartet of micromeres. We observed clear yolk bodies in the egg capsules of some eggs ribbons at early stages of development. Both reproductive and embryological characteristics, such as presence of stomodeum in the larva, and ingestion of particles after hatching confirmed the planktotrophic veliger larvae of this species, consistent with the majority of sacoglossans from the Eastern and Northeast Pacific Oceans.

The encapsular developmental sequence of the mesogastropod Turritella communis (Gastropoda: Turritellidae)

1992 ◽  
Vol 72 (4) ◽  
pp. 783-805 ◽  
Author(s):  
J. J. Kennedy ◽  
B. F. Keegan
Keyword(s):  
Germinal Vesicle ◽  
Average Diameter ◽  
Meiotic Maturation ◽  
Developmental Sequence ◽  
Early Cleavage ◽  
Mantle Tissue ◽  
Cell Stage ◽  
Egg Capsules ◽  
Eupyrene Sperm ◽  
The Right

The development of the lecithotrophic encapsulated larva of the internally-fertilizing, sublittoral gastropod Turritella communis Risso 1826 was documented using scanning electron microscopy and light microscopy. Encapsulated development was completed in 12 days at 15°C in the laboratory. Spawning occurred above ~10°C. Spawn masses consisted of numerous gelatinous egg capsules, each of which contained ~28 eggs, encased in albumen and fertilizing sperm. The eggs had an average diameter of 139 μm. Fertilization was accomplished by unpaired eupyrene sperm and occurred at the germinal vesicle stage. The developmental sequence followed the typical gastropod pattern, but was unique in a number of respects. Polar lobes were produced during meiotic maturation and early cleavage, with an especially large lobe occurring in association with the first cleavage, which was unequal. The blastula developed into a dorso-ventrally flattened placula at the 70-cell stage. Gastrulation occurred through invagination and epiboly acting together, and was uniquely accompanied by the development of ectodermal microvilli measuring ~ 1 μm in length. Extra-embryonic albumen began to be depleted after the development of the microvilli. It is proposed that the ciliated telotrochal cells gave rise to the pair of statocysts. Torsion was additionally observed to be facilitated by the growth of pre-mantle tissue on the right side and retardation of growth on the left side.

scholarly journals Ngwevu intloko: a new early sauropodomorph dinosaur from the Lower Jurassic Elliot Formation of South Africa and comments on cranial ontogeny in Massospondylus carinatus

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7240 ◽  
Author(s):  
Kimberley E.J. Chapelle ◽  
Paul M. Barrett ◽  
Jennifer Botha ◽  
Jonah N. Choiniere
Keyword(s):  
South Africa ◽  
New Species ◽  
Sexual Dimorphism ◽  
New Genus ◽  
Lower Jurassic ◽  
Early Jurassic ◽  
Adult Size ◽  
Minimum Age ◽  
Cranial Ontogeny ◽  
Morphological Differences

Our knowledge of Early Jurassic palaeobiodiversity in the upper Elliot Formation of South Africa has increased markedly in recent years with the discovery of new fossils, re-assessments of previously collected material and a better understanding of Stormberg Group stratigraphy. Here, Ngwevu intloko, a new genus of upper Elliot basal sauropodomorph is named on the basis of a complete skull and partial skeleton (BP/1/4779) previously assigned to Massospondylus carinatus. It can be distinguished from all other basal sauropodomorphs by a combination of 16 cranial and six postcranial characters. The new species is compared to a small ontogenetic series of M. carinatus as well as to a range of closely related taxa. Taphonomic deformation, sexual dimorphism and ontogeny are rejected as possible explanations for the morphological differences present between BP/1/4779 and other taxa. Osteohistological examination reveals that BP/1/4779 had nearly reached adult size at the time of its death at a minimum age of 10 years.

Integrative taxonomic revision of the New Caledonian endemic genus Taophila Heller (Coleoptera: Chrysomelidae, Eumolpinae)

2021 ◽  
pp. 1-74
Author(s):  
Leonardo Platania ◽  
Jesús Gómez-Zurita
Keyword(s):  
New Caledonia ◽  
Taxonomic Revision ◽  
Actual Number ◽  
Mtdna Sequences ◽  
Endemic Genus ◽  
Number Of Species ◽  
Morphological Differences ◽  
Mtdna Introgression ◽  
Eleven Species ◽  
Mtdna Genealogy

Abstract There are 96 endemic species of Eumolpinae (Coleoptera: Chrysomelidae) described from New Caledonia, but some estimates propose that the actual number could be at least twice this figure. Not surprisingly, when a particular species assemblage has been revised, the number of species in that group increases significantly. Here, we revise the New Caledonian endemic genus Taophila Heller, 1916, the best studied in this fauna and currently known to include eleven species, one in the subgenus Jolivetiana Gómez-Zurita & Cardoso, 2014, and ten in the nominal subgenus. The analysis of morphological differences in a large sample of Taophila and the validation of the resulting species hypotheses in an integrative fashion based on a phylogenetic analysis of partial mtDNA sequences (cox1 and rrnS) resulted in the addition of eleven more taxa. Taxonomic splits mainly reinterpreted the previous observation of mtDNA paraphyly affecting T. subsericea Heller, 1916, shown to represent a complex of species mostly distinguishable by diagnostic differences among females. The new species described are: T. bituberculata n. sp., T. carinata n. sp., T. dapportoi n. sp., T. davincii n. sp., T. draco n. sp., T. goa n. sp., T. hackae n. sp., T. samuelsoni n. sp., T. sideralis n. sp., T. taaluny n. sp. and T. wanati n. sp. These additions and the synonymy T. subsericea Heller = Stethotes mandjeliae Jolivet, Verma & Mille, 2010 n. syn., bring to 21 the total number of species in Taophila. Moreover, we also found the first evidence of mtDNA introgression between species of New Caledonian Eumolpinae, resulting from putative recent hybridization of T. subsericea and T. dapportoi where these species coexist. We describe a model incorporating the mtDNA genealogy of T. subsericea about the conditions that may have favored the secondary geographic encounter required for the hybridization of these species.

Ex situ conservation of American chestnut (Castanea dentata (Marsh.) Borkh.) and butternut (Juglans cinerea L.), a review

2000 ◽  
Vol 76 (5) ◽  
pp. 765-774 ◽  
Author(s):  
Ken McIlwrick ◽  
S. Wetzel ◽  
T. Beardmore ◽  
K. Forbes
Keyword(s):  
Genetic Information ◽  
Ex Situ Conservation ◽  
In Situ Conservation ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Ex Situ ◽  
Juglans Cinerea ◽  
Research Areas

Two tree species native to North America, American chestnut (Castanea dentata (Marsh.) Borkh.) and butternut (Juglans cinerea L.), which have experienced rapid declines in their populations due to similar stressors (disease and changes in land use), are used as examples of how these species would benefit from ex situ conservation efforts. Current and past ex situ and in situ conservation efforts for these species are discussed and the focus of this review is on two key research areas: 1) what needs to be preserved (genetic information) and 2) how to preserve these trees or germplasm. Key words: butternut, American chestnut, Cryphonectria parasitica, Sirococcus clavigignenti-juglandacearum, ex situ conservation

258 THE PRELIMINARY RESULTS OF IN VITRO PRODUCTION OF THE WISENT HYBRID EMBRYOS

2015 ◽  
Vol 27 (1) ◽  
pp. 219
Author(s):  
A. M. Duszewska ◽  
W. Olech ◽  
P. Trzeciak ◽  
M. Krzysiak ◽  
L. Rapala ◽  
...  
Keyword(s):  
Threatened Species ◽  
Bos Taurus ◽  
Ex Situ ◽  
European Bison ◽  
Bison Bonasus ◽  
In Vitro Production ◽  
Cell Stage ◽  
Culture Development ◽  
Humidified Air

Wisent (Bison bonasus), also called the European bison, is listed as vulnerable on the International Union for the Conservation of Nature Red List of Threatened Species. In Poland, a program for protection in situ and ex situ is being implemented. One new approach is the use of the in vitro embryo production (IVP) procedures to obtain wisent offspring. In contrast to previous successes with cattle IVP, use of IVP with wisent is limited by the small size of the population (only ~5000 individuals in more than 200 herds in Europe) and seasonal reproduction. The aim of this preliminary study was to obtain hybrid embryos (Bison bonasus × Bos taurus) in vitro. Ovaries were isolated from wisent females outside the reproductive season and eliminated from breeding for reasons other than infertility. Cumulus-oocytes complexes (COC) were isolated from all follicles above 2 mm in diameter. All COC were matured in TCM 199 supplemented with 10% fetal bovine serum, 0.02 IU mL–1 of porcine FSH, 17 β-oestradiol, 0.2 mM Na pyruvate, and antibiotics. The COC were cultured for 24 h at 38.5°C and 5% CO2 in humidified air. The matured COC (Bison bonasus) were fertilized in vitro with sperm from Jersey bulls (Bos taurus) in TALP supplemented with 6 mg mL–1 of fatty acid free BSA (BSA FAF), 0.2 mM Na pyruvate, 20 µM penicillamine,10 µM hypotaurine, 1 µM epinephrine, 2 µg mL–1 heparin, and antibiotics. Spermatozoa were used at a final concentration of 1 × 105 per oocyte and were co-cultured for 18 h at 38.5°C and 5% CO2 in humidified air. The hybrid zygotes were cultured in KSOM supplemented with 5 µg mL–1 of MEM Nonessential Amino Acid Solution (100×), 3 mg mL–1 of BSA FAF, and antibiotic for 192 h at 38.5°C and 5% CO2 in humidified air. The medium was partly replaced by fresh medium after 48 and 144 h of culture. Development was evaluated every day. From 25 COC isolated from wisent ovaries, only 18 COC were qualified for in vitro maturation (60%). Of these, 15 COC (83.3%) matured. The percentage of hybrid embryos that cleaved was 80% after 48 h of culture, and the percentage of embryos that developed up to the 8-cell stage was 33% after 96 h of culture. The morula/blastocyst rate was 26.6% after 192 h of culture, as represented by 1 early blastocyst, 2 compact morulae, and 1 morula. The use of the cattle IVP procedure allowed to receive hybrid embryos (Bison bonasus × Bos taurus), but they developed slower than cattle embryos under the same conditions, based on our previous studies. This research will be continued and may make a contribution to the protection of this threatened species.

A TAXONOMIC STUDY OF THE GENUS HEDOPHYLLUM SETCHELL

1965 ◽  
Vol 43 (11) ◽  
pp. 1409-1420 ◽  
Author(s):  
Thomas B. Widdowson
Keyword(s):  
Type Species ◽  
Gulf Of Alaska ◽  
Taxonomic Study ◽  
Field Observations ◽  
Northeast Pacific ◽  
Mechanical Effects ◽  
Juan De Fuca ◽  
Variable Species ◽  
Morphological Differences ◽  
Juan De Fuca Strait

The genus Hedophyllum Setchell consists of one variable species, H. sessile (C. Ag.) Setchell. Field observations and experiments show that H. subsessile Setchell was based upon a form characteristic of the type species in the second summer of its life. H. spirale Yendo is reduced to synonymy with Laminaria bongardiana P. et R., and H. kuroshioense Segawa is transferred to the genus Laminaria.Observations of the genus in the field throughout most of its range in the northeast Pacific indicate morphological differences between populations in the areas east and west of Yakutat, in the Gulf of Alaska. These differences appear to be related to sea temperature.Morphological variations in populations of Hedophyllum studied along Juan de Fuca Strait appear to be caused by exposure to sunlight and the mechanical effects of wave action.

scholarly journals Research work on Vitis vinifera ssp. sylvestris in Slovakia

2010 ◽  
Vol 46 (Special Issue) ◽  
pp. S47-S49 ◽  
Author(s):  
D. Pospíšilová ◽  
R. Šimora ◽  
D. Sekera
Keyword(s):  
Vitis Vinifera ◽  
Leaf Shape ◽  
Research Work ◽  
Flowering Plants ◽  
Ex Situ ◽  
State Of Health ◽  
Wild Grapevine ◽  
Morphological Differences ◽  
Vitis Sylvestris

&nbsp;By 2008, twelve localities had been investigated. At each location we assessed the degree of threats to the wild grapevine. Flowering plants were seldom found. The plants found were localized geographically, and 149 vines were described using the characteristics of shoot types and leaves, using the O.I.V. descriptor list. Morphological differences of the leaf shape, hair or bristle density are high. A few seeds which were found in dry black berries are much smaller in size than the seeds of <I>Vitis vinifera </I>ssp. <I>sativa</I>. From plants that were easily attainable, cuttings were taken with the objective to multiply the <I>Vitis sylvestris </I>and to establish an <I>ex situ </I>collection. In 2008, we repeated the procedure with 54 vines. The state of health of the vines <I>in situ </I>is very good. No fungal diseases were visible, and mites occurred only rarely. In the nursery, some plants were contaminated by mildew.

scholarly journals Morphological differences in embryos of goldfish (Carassius auratus auratus) under different incubation temperatures

2019 ◽  
Vol 63 (11-12) ◽  
pp. 597-604 ◽  
Author(s):  
Hirotaro Urushibata ◽  
Eisuke Takahashi ◽  
Yu Shimizu ◽  
Toshiya Miyazaki ◽  
Takafumi Fujimoto ◽  
...  
Keyword(s):  
Carassius Auratus ◽  
Morphological Characteristics ◽  
Temperature Tolerance ◽  
Cell Stage ◽  
Animal Pole ◽  
Goldfish Carassius Auratus ◽  
Morphological Differences ◽  
Incubation Temperatures ◽  
Single Batch

The goldfish (Carassius auratus auratus) is a useful species for embryonic micromanipulations because of its large egg size and wide temperature tolerance. Here, we describe in detail the rate of development and morphological characteristics of goldfish embryos incubated at temperatures between 10 &deg;C and 30 &deg;C. The cleavage speed increased rapidly as temperature increased. Synchronized cell divisions occurred at 131 min intervals at 10ºC, at 33 min intervals at 20 &deg;C, and at 19 min intervals at 30 &deg;C during the cleavage period. The rate of hatched abnormal embryos significantly increased at temperatures of 26 &deg;C and above, while there was no change in the number of abnormal embryos at temperatures less than 24 &deg;C. Moreover, the blastomeres around the center of the blastodisc rose in the direction of the animal pole at temperatures less than 14 &deg;C. At the lower temperatures, clusters of maternally-supplied germplasm were visualized both at the ends of the first three cleavage furrows and at the border between the lower and upper tiers at the 16- to 32-cell stage, with injection of artificial mRNA and vasa in situ hybridization. This study showed that temperature affects not only developmental speed but also the shape of the blastodisc and the distribution of maternally-supplied materials in the blastodisc. By controlling the temperature, it is possible for researchers to prepare many stages of embryos and shapes of the blastodisc from a single batch of eggs.

The breeding cycle and growth of open coast and estuarine populations ofLittorina littorea

1972 ◽  
Vol 52 (4) ◽  
pp. 1011-1019 ◽  
Author(s):  
J. D. Fish
Keyword(s):  
Shell Height ◽  
Littorina Littorea ◽  
Breeding Cycle ◽  
Spawning Activity ◽  
Egg Capsules ◽  
Open Coast ◽  
Full Development ◽  
Veliger Larvae ◽  
First Time ◽  
Sexually Mature

The breeding cycle and growth of a population of Littorina littorea (L.)from an exposed rocky shore is compared with a population from a neighbouring sheltered estuarine habitat. The estuarine population matures earlier in the year, and maximum spawning activity is recorded in January compared with March on the open coast. This is considered to be the result of the higher nutritional status of the estuary. Egg capsules and veliger larvae have been found amongst the detritus on the estuary, and the establishment of an earlier settlement in this population is explained by concluding that a substantial proportion of the egg capsules do not leave the estuary, but undergo their full development in the moist detritus. At both localities individuals are sexually mature at a shell height of about 11–12 mm. Snails from the estuary reproduce for the first time during their second winter compared with the second or third winter for the open coast population.

scholarly journals Snails associated with the coral-killing sponge Terpios hoshinota in Okinawa Island, Japan

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hideyuki Yamashiro ◽  
Hiroaki Fukumori ◽  
Siti Nurul Aini ◽  
Yurika Hirose
Keyword(s):  
Cytochrome Oxidase ◽  
Direct Observation ◽  
Close Association ◽  
Cytochrome Oxidase I ◽  
Sponge Tissue ◽  
Okinawa Island ◽  
Molecular Analyses ◽  
Egg Capsules ◽  
Terpios Hoshinota ◽  
Veliger Larvae

AbstractTerpios hoshinota is a thin encrusting sponge that overgrows live scleractinian corals and it is linked to coral loss in many reefs. However, our knowledge of the species associated with this sponge species is poor. During a periodical survey of T. hoshinota in 2020, we found tiny snails crawling on the sponge in the subtropical waters around Okinawa Island, Japan. We observed egg capsules inside the sponge tissue and veliger larvae released from the egg capsules. Molecular analyses of both the snails and veliger larvae (cytochrome oxidase I, COI) showed that they were identical and belonged to Joculator sp. (family Cerithiopsidae). There was no direct observation of predation on the sponge by this snail; however, to the best of our knowledge, this is the first report on a close association between a snail and the sponge T. hoshinota.

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