The morphology of free-living stages and immature parasites of Rhabdias paraensis (Nematoda: Rhabdiasidae), a parasite of Rhinella marina (Anura: Bufonidae) in Brazil

2016 ◽  
Vol 61 (1) ◽  
Author(s):  
Francisco Tiago de Vasconcelos Melo ◽  
Luciana de Cássia Silva do Nascimento ◽  
Lilian Cristina Macedo ◽  
Jeannie Nascimento dos Santos ◽  
Yuriy Kuzmin
Keyword(s):  
Life Cycle ◽  
Buccal Capsule ◽  
Original Description ◽  
Species Determination ◽  
Free Living ◽  
Rhinella Marina ◽  
Additional Information ◽  
New Information ◽  
Apical View

AbstractRhabdias paraensis Santos, Melo, Nascimento, Nascimento, Giese et Furtado, 2011 was described based on fully gravid worms. Further investigations on the free-living stages, immature worms and young individuals were facilitated by cultivation in the laboratory, which allowed us to add new information about the morphology and development of the species. Observations on the free-living development of R. paraensis showed that the life cycle is typical of Rhabdias, with alternation of gonochoristic and hermaphroditic generations and without homogony. Males of the free-living generation were different from those in several species of the genus studied previously. In the original description, the excretory glands and duct were absent in gravid specimens of R. paraensis, while in this study, distinct excretory glands and a duct were observed in immature and young individuals. Additionally, we recognised the separation of the buccal capsule walls into anterior and posterior portions and described the specific shapes of these portions in lateral and apical view. Studies on the morphology and development of free-living stages of Rhabdias spp. from Neotropical regions may provide additional information for species determination.

Description, molecular characterization and life cycle of Serpentirhabdias mussuranae n. sp. (Nematoda: Rhabdiasidae) from Clelia clelia (Reptilia: Colubroidea) in Brazil

2019 ◽  
Vol 94 ◽  
Author(s):  
Y. Kuzmin ◽  
V.V. Tkach ◽  
F.T.V. Melo
Keyword(s):  
New Species ◽  
Life Cycle ◽  
Nuclear Ribosomal Dna ◽  
Free Living ◽  
Larval Stages ◽  
Triangular Shape ◽  
Oral Opening ◽  
Molecular Phylogenetic ◽  
Apical View ◽  
Amazonas State

Abstract Serpentirhabdias mussuranae n. sp. is described from the lungs of the mussurana, Clelia clelia (Daudin, 1803), from vicinities of Lábrea, Amazonas State, Brazil. The species is characterized by the triangular oral opening, the presence of teeth (onchia) in the oesophastome, the excretory glands longer than the oesophagus and the tail abruptly narrowing in its anterior half and gradually tapering in posterior half. Among the Neotropical representatives of the genus, three species are known to possess the onchia in the oesophastome: S. atroxi, S. moi and S. viperidicus. Serpentirhabdias mussuranae n. sp. differs from S. atroxi and S. viperidicus by its triangular shape of the oral opening and the oesophastome in apical view, vs. round in the latter two congeners. Additionally, S. viperidicus has a larger oesophastome, 13–22 micrometers wide and 13–23 micrometers deep. The new species has relatively longer excretory glands than S. moi. The new species is morphologically and genetically close to S. atroxi, S. moi and S. viperidicus, all parasitic in Brazilian snakes, based on the presence of onchia and the comparison of nucleotide sequences of nuclear ribosomal DNA and mitochondrial cox1 gene (differences varied between 3.8% and 7.1%). Data on the life cycle of S. mussuranae n. sp. is provided, and the life cycle is typical of the genus Serpentirhabdias, with the combination of direct development and heterogony. Free-living larval stages and the adults of amphimictic free-living generation are described. The results of molecular phylogenetic analysis based on nuclear ribosomal internal transcribed spacer (ITS) + partial 28S region and partial mitochondrial cox1 gene are provided.

Additions to the description, reproduction and systematic position of the enigmatic species Acritagasyllis longichaetosus Lucas, San Martín & Sikorski, 2010 (Annelida: Phyllodocida: Syllidae)

2015 ◽  
Vol 96 (8) ◽  
pp. 1709-1716 ◽  
Author(s):  
Alessandra Rivolta ◽  
Guillermo San Martín ◽  
Andrey Sikorski
Keyword(s):  
Phylogenetic Analysis ◽  
Morphological Characteristics ◽  
Original Description ◽  
Systematic Position ◽  
Pharyngeal Tooth ◽  
Additional Information ◽  
New Information ◽  
New Diagnosis ◽  
First Time ◽  
San Martín

We present some additional information to Acritagasyllis longichaetosus Lucas, San Martín & Sikorski 2010, the only representative of an enigmatic genus of Syllidae from subpolar areas off Norway, based on two newly found specimens and one male and another female stolons. The armature of the pharynx was incorrectly interpreted in the original description, having in fact a trepan instead of a single pharyngeal tooth as originally described. The reproductive stolons are herein described for the first time. With this new information we performed a maximum parsimony phylogenetic analysis that placed this genus within the subfamily Autolytinae, despite its peculiar morphological characteristics. For this reason, we propose a new diagnosis to the genus Acritagasyllis as well as a modified diagnosis of the subfamily Autolytinae.

scholarly journals Misinformation tactics protect rare birds from problem predators

2021 ◽  
Vol 7 (11) ◽  
pp. eabe4164
Author(s):  
Grant L. Norbury ◽  
Catherine J. Price ◽  
M. Cecilia Latham ◽  
Samantha J. Brown ◽  
A. David M. Latham ◽  
...  
Keyword(s):  
Decision Making ◽  
Threatened Species ◽  
Prey Availability ◽  
Free Living ◽  
Bird Populations ◽  
New Information ◽  
Mammalian Predators ◽  
Decision Making Processes ◽  
Living Species ◽  
Information Reliability

Efficient decision-making integrates previous experience with new information. Tactical use of misinformation can alter choice in humans. Whether misinformation affects decision-making in other free-living species, including problem species, is unknown. Here, we show that sensory misinformation tactics can reduce the impacts of predators on vulnerable bird populations as effectively as lethal control. We repeatedly exposed invasive mammalian predators to unprofitable bird odors for 5 weeks before native shorebirds arrived for nesting and for 8 weeks thereafter. Chick production increased 1.7-fold at odor-treated sites over 25 to 35 days, with doubled or tripled odds of successful hatching, resulting in a 127% increase in modeled population size in 25 years. We demonstrate that decision-making processes that respond to changes in information reliability are vulnerable to tactical manipulation by misinformation. Altering perceptions of prey availability offers an innovative, nonlethal approach to managing problem predators and improving conservation outcomes for threatened species.

Preliminary investigations into the life cycle of Ventruia inaequalis (Cooke) WINT. in South Australia.

1953 ◽  
Vol 4 (4) ◽  
pp. 415 ◽  
Author(s):  
MW Jeffery
Keyword(s):  
Life Cycle ◽  
Primary Infection ◽  
South Australia ◽  
Late Summer ◽  
Relative Importance ◽  
New Information ◽  
One Year

Investigation into the possible sources of primary infection by the fungus Ventruia inaequalis (Cooke) Wint. in spring has been carried out. The results present new information on the life cycle of the pathogen under South Australian conditions. Sources of primary infection, such 'as lesions on one-year-old wood or overwintering superficial conidia on the trees, do not appear important. Bud-scale infection of dormant buds has been shown, and its relative importance is discussed. Ascospores are the most important source of primary infection. Their period of discharge extends to a later date than previously reported for South Australia and is considered in relation to leader shoot and late summer spot infection.

scholarly journals Nematode Hsp90: highly conserved but functionally diverse

Parasitology ◽  
2014 ◽  
Vol 141 (9) ◽  
pp. 1203-1215 ◽  
Author(s):  
VICTORIA GILLAN ◽  
EILEEN DEVANEY
Keyword(s):  
Life Cycle ◽  
Heat Shock Protein 90 ◽  
Ecological Niches ◽  
Actual Number ◽  
Host Organism ◽  
Free Living ◽  
Parasitic Species ◽  
Free Living Nematode ◽  
Functionally Diverse

SUMMARYNematodes are amongst the most successful and abundant organisms on the planet with approximately 30 000 species described, although the actual number of species is estimated to be one million or more. Despite sharing a relatively simple and invariant body plan, there is considerable diversity within the phylum. Nematodes have evolved to colonize most ecological niches, and can be free-living or can parasitize plants or animals to the detriment of the host organism. In this review we consider the role of heat shock protein 90 (Hsp90) in the nematode life cycle. We describe studies on Hsp90 in the free-living nematode Caenorhabditis elegans and comparative work on the parasitic species Brugia pahangi, and consider whether a dependence upon Hsp90 can be exploited for the control of parasitic species.

scholarly journals Redescription of Charaxicephaloides polyorchis Groschaft and Tenora 1978 (Digenea: Pronocephalidae) from the green turtle Chelonia mydas in Costa Rica

2009 ◽  
Vol 46 (2) ◽  
pp. 97-99 ◽  
Author(s):  
M. Santoro ◽  
P. Brandmayr ◽  
E. Greiner ◽  
J. Morales ◽  
B. Rodríguez-Ortíz
Keyword(s):  
Costa Rica ◽  
Host Species ◽  
Green Turtle ◽  
Chelonia Mydas ◽  
Original Description ◽  
Northwest Coast ◽  
Green Turtles ◽  
New Information

AbstractCharaxicephaloides polyorchis Groschaft and Tenora, 1978 is redescribed on the basis of specimens collected from the stomach of green turtles Chelonia mydas in Costa Rica. Our specimens are consistent with the original description which was based on four flukes from the same host species from the northwest coast of Cuba. Our redescription provides a new range of variations and adds new information on this species. This represents only the second record of C. polyorchis in green turtles.

Observing microscopic phases of lichen life cycles on transparent substrata placed in situ

2005 ◽  
Vol 37 (5) ◽  
pp. 373-382 ◽  
Author(s):  
William B. SANDERS
Keyword(s):  
Life Cycle ◽  
Developmental Stages ◽  
Life Cycles ◽  
Potential Significance ◽  
Free Living ◽  
Lichen Community ◽  
One Year ◽  
The One ◽  
Observation Period

The utility of plastic cover slips as a substratum for in situ study of lichen developmental stages is further explored in a neotropical foliicolous lichen community and in a European temperate corticolous community. Twenty-one months after placement in the tropical forest, the cover slips bore foliicolous lichen thalli with several species producing characteristic ascocarps and ascospores, indicating the suitability of the substratum for completion of the life cycle of these lichens. On cover slips placed within the temperate corticolous community, lichen propagules anchored to the substratum with relatively short attachment hyphae but did not develop further within the one year observation period. Intimately intermixed microbial communities of short-celled, mainly pigmented fungi and chlorophyte algae developed upon the transparent substratum. Among the algae, Trebouxia cells, often in groups showing cell division and without associated lichenizing hyphae, were commonly observed. The potential significance of the free-living populations in the life cycle of Trebouxia and in those of Trebouxia-associated lichen fungi is discussed.

Autonomy and integration in complex parasite life cycles

Parasitology ◽  
2016 ◽  
Vol 143 (14) ◽  
pp. 1824-1846 ◽  
Author(s):  
DANIEL P. BENESH
Keyword(s):  
Life Cycle ◽  
Holistic Approach ◽  
Life Cycles ◽  
Complex Life Cycle ◽  
Functional Specialization ◽  
Life Stages ◽  
Free Living ◽  
New Host ◽  
Complex Life Cycles ◽  
Life Cycle Stages

SUMMARYComplex life cycles are common in free-living and parasitic organisms alike. The adaptive decoupling hypothesis postulates that separate life cycle stages have a degree of developmental and genetic autonomy, allowing them to be independently optimized for dissimilar, competing tasks. That is, complex life cycles evolved to facilitate functional specialization. Here, I review the connections between the different stages in parasite life cycles. I first examine evolutionary connections between life stages, such as the genetic coupling of parasite performance in consecutive hosts, the interspecific correlations between traits expressed in different hosts, and the developmental and functional obstacles to stage loss. Then, I evaluate how environmental factors link life stages through carryover effects, where stressful larval conditions impact parasites even after transmission to a new host. There is evidence for both autonomy and integration across stages, so the relevant question becomes how integrated are parasite life cycles and through what mechanisms? By highlighting how genetics, development, selection and the environment can lead to interdependencies among successive life stages, I wish to promote a holistic approach to studying complex life cycle parasites and emphasize that what happens in one stage is potentially highly relevant for later stages.

Propeller thrust force contribution to airplane longitudinal stability

2018 ◽  
Vol 90 (9) ◽  
pp. 1474-1478
Author(s):  
Miodrag Milenković-Babić
Keyword(s):  
Stability Analysis ◽  
Thrust Force ◽  
Standard Procedure ◽  
Longitudinal Stability ◽  
Content Type ◽  
Additional Information ◽  
New Information ◽  
Practical Implications ◽  
Theoretical Results ◽  
Propeller Thrust

Purpose This paper aims to present the new information about propeller thrust force contribution to airplane longitudinal stability analysis. Design/methodology/approach The method presented in this paper is empirical, shows how propeller thrust force derivative can be obtained and gives some additional information about misinterpretation of the propeller thrust effects that are present in the current literature. Findings New information about propeller thrust force contribution to airplane longitudinal stability analysis has been presented. This information should enable more precise insight in aircraft stability analysis and better understanding of the physical process that occurs during maneuver flight. Practical implications The information presented in this paper is new and specific to the propeller aircraft configuration. The methods used here are standard procedure to evaluating propeller thrust force derivative. Originality/value The information in this paper presents theoretical results. The method for calculating thrust force contribution to the airplane longitudinal stability is given depending on the propeller type and should enable good engineering results.

Memoirs: An Account of Amoeba Discoides; its Culture and Life History

1938 ◽  
Vol s2-80 (319) ◽  
pp. 459-478
Author(s):  
CATHERINE HAYES
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Amoeba Proteus ◽  
Tropical Fish ◽  
Free Living ◽  
Free Living Amoeba ◽  
College Laboratory ◽  
Petri Dishes ◽  
Fish Tanks

1. A large free-living amoeba found by Mr. Harry Watkinson in the tropical fish tanks of Mr. Albert Sutcliffe of Grimsby has been identified as Amoeba discoides (Schaeffer, 1916) = Metachaos discoides (Schaeffer, 1926). 2. From the inoculation material obtained from these tanks Amoeba discoides has been successfully cultivated in the Notre Dame Training College Laboratory by a technique similar to that used for the cultivation of Amoeba proteus: wheat being the pabulum employed. In contrast to what obtains in the cultivation of Amoeba proteus , however, Amoeba discoides flourishes more luxuriantly in shallow Petri dishes, than in deeper troughs. 3. The nucleus in the resting and dividing stages is described; division is amitotic. 4. The more important cytoplasmic contents, including nutritive spheres, and crystals are likewise described. 5. The life-history has been worked out. The adult amoeba becomes an agamont giving rise to agametes which eventually grow into adult amoebae, the life-cycle occupying roughly about four months. 6. Descriptions of the nucleus of the newly hatched and developing amoebae are deferred. I wish to offer my sincerest thanks to Professor Graham Kerr under whom this work was begun, and who has continued from afar to watch over it with ever kindly interest and encouragement and who has read the paper in typescript. My thanks are also extended to Professor Hindle, under whom the work was completed, for his kind advice and for reading the paper in typescript. In conclusion I would like to express my appreciation of her skill and of the care and trouble bestowed by Miss Brown Kelly in the execution of the original drawing of fig. 1, PI. 31.

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