scholarly journals Gonad morphology of Rhyacichthys aspro (Valenciennes, 1837), and the diagnostic reproductive morphology of gobioid fishes

2021 ◽  
Author(s):  
Kathleen S. Cole ◽  
Lynne R. Parenti
Keyword(s):  
Reproductive Morphology ◽  
Gonad Morphology ◽  
Gobioid Fishes

Gonad morphology and gametogenesis in the deep-sea jellyfish Atolla wyvillei and Periphylla periphylla (Scyphozoa: Coronatae) collected from Cape Hatteras and the Gulf of Mexico

2009 ◽  
Vol 90 (6) ◽  
pp. 1095-1104 ◽  
Author(s):  
Cathy H. Lucas ◽  
Adam J. Reed
Keyword(s):  
Gulf Of Mexico ◽  
Gonad Development ◽  
Bell Diameter ◽  
Western Atlantic ◽  
Gonad Morphology ◽  
Time Period ◽  
Cape Hatteras ◽  
Literature Evidence ◽  
Long Time ◽  
North Western

Observations on gonad morphology and the structure of ovaries and testes of the coronate scyphozoans Atolla wyvillei and Periphylla periphylla are described based on samples collected from the Gulf of Mexico and Cape Hatteras (north-western Atlantic). In A. wyvillei, gonads of distinguishable sex were observed in medusae as small as 17 mm bell diameter (BD). Spermatogenesis occurred within follicles (average 366 × 254 μm) that were evenly distributed throughout the gonad. Oocytes in different stages of development were observed in all the females with gonads. Oocytes arise from the gastrodermis and migrate into the mesoglea to develop from early-mid to late vitellogenic oocytes characterized by a large nucleus and granular (organic-rich) cytoplasm. The largest oocytes measured were 543 μm and 263 μm from the Gulf of Mexico and Cape Hatteras respectively. Possible reasons for this difference are discussed. In P. periphylla gonads were also initially observed in medusae 17 mm BD, although not all larger medusae had obvious gonads. Unlike A. wyvillei sperm follicles were arranged in long convoluted rows normally only one follicle thick. The organization of ooytes in female P. periphylla was very similar to A. wyvillei, although the gonads were small and the number of oocytes present in each gonad very low (<22). The largest oocyte measured was 777 μm in a 53 mm BD medusa. Although medusae were collected from one time period only (September) in this study, our findings appear to be in agreement with literature evidence indicating that coronate jellyfish produce few eggs continuously over a long time period. Aspects of gonad development and gametogenesis are discussed with respect to potential differences in site productivity and species identification.

scholarly journals Male sexual ornament size is positively associated with reproductive morphology and enhanced fertility in the stalk-eyed fly Teleopsis dalmanni

2008 ◽  
Vol 8 (1) ◽  
pp. 236 ◽  
Author(s):  
David W Rogers ◽  
Matthew Denniff ◽  
Tracey Chapman ◽  
Kevin Fowler ◽  
Andrew Pomiankowski
Keyword(s):  
Reproductive Morphology ◽  
Sexual Ornament

Mesocyparis borealis gen. et sp. nov.: fossil Cupressaceae from the early Tertiary of Saskatchewan, Canada

1987 ◽  
Vol 65 (11) ◽  
pp. 2338-2351 ◽  
Author(s):  
E. E. McIver ◽  
J. F. Basinger
Keyword(s):  
Northern Hemisphere ◽  
Branching Pattern ◽  
Natural Group ◽  
Classification Schemes ◽  
Cone Structure ◽  
Reproductive Morphology ◽  
Extant Genus ◽  
Early Tertiary ◽  
Seed Cone ◽  
First Time

Fossil cedar foliage of the Cupressinocladus interruptus type, with associated seeds and cones, is locally abundant in Paleocene deposits of the Ravenscrag Formation, southwestern Saskatchewan, Canada. Vegetative remains of this type occur frequently in early Tertiary plant assemblages throughout the northern hemisphere, indicating that this now extinct cedar was once widespread. For the first time this cedar can be described on the basis of both vegetative and reproductive morphology. Foliage is frond-like with a characteristic opposite branching pattern. Seed cones are globose and woody and bear four equal and decussate scales with prominent umbos. Seeds bear large, equal, semicircular wings. The fossil cedar appears most closely related to extant Cupressaceae such as Thuja, Chamaecyparis, and Heyderia. Foliage closely resembles that of Thuja, while cones are most similar to those of Chamaecyparis. The fossil differs sufficiently in foliage and seed cone structure to preclude assignment to an extant genus and is here assigned to Mesocyparis borealis gen. et sp. nov. Similarities among such extant genera as Thuja, Chamaecyparis, Heyderia, and Thujopsis and the fossil Mesocyparis borealis suggest that all may belong to a single natural group. Furthermore, this group may be more closely related to the southern hemispheric genera Libocedrus, Papuacedrus, and Austrocedrus than present classification schemes imply. Our examination of the Cupressaceae indicates that a revision of present systems of classification is required to accommodate evidence from both extant and extinct cedars.

scholarly journals Effect of competitive cues on reproductive morphology and behavioral plasticity in male fruitflies

2015 ◽  
Vol 27 (2) ◽  
pp. 452-461 ◽  
Author(s):  
Amanda Bretman ◽  
Claudia Fricke ◽  
James D. Westmancoat ◽  
Tracey Chapman
Keyword(s):  
Behavioral Plasticity ◽  
Reproductive Morphology

Reproductive Morphology of the Anchialine Shrimp Procaris ascensionis (Decapoda: Procarididae)

1988 ◽  
Vol 8 (3) ◽  
pp. 333 ◽  
Author(s):  
Bruce E. Felgenhauer ◽  
Lawrence G. Abele ◽  
Won Kim
Keyword(s):  
Reproductive Morphology
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