Developing embryo and cyclic changes in the uterus of Peripatus (Macroperipatus) acacioi (Onychophora, Peripatidae)

@article{Campiglia1995DevelopingEA,
  title={Developing embryo and cyclic changes in the uterus of Peripatus (Macroperipatus) acacioi (Onychophora, Peripatidae)},
  author={S. Campiglia and M. Walker},
  journal={Journal of Morphology},
  year={1995},
  volume={224}
}
Female reproductive tracts of the viviparous neo‐tropical onychophoran Peripatus acacioi have been examined at different times throughout the year, and the altering relationship between the developing embryo and the uterus is described. Depending on her age and time of year, the female may have one or two generations of embryos within her uterus. The uterine wall consists of a thin outer epithelium and basal lamina, three layers of muscles, and a thick basal lamina beneath an inner epithelium… Expand
Studies of embryonic development and the reproductive cycle in ovoviviparous Australian Onychophora (Peripatopsidae)
TLDR
Analysis of the developmental stages of the embryos present in females collected throughout a calendar year has shown that there is an annual reproductive cycle with a total gestation period of c. Expand
The female genital system of Ooperipatellus decoratus (Onychophora, Peripatopsidae): An ultrastructural study
The female genital system of the oviparous peripatopsid Ooperipatellus decoratus consists of an ovary, oviducts equipped with receptacula seminis and additional pouches, uteri, and a vagina. It isExpand
Ultrastructure of the eggshell and its formation in Planipapillus mundus (Onychophora: Peripatopsidae)
TLDR
Examination of oocytes in the ovary and developing eggs at various stages of passage through the uterus indicate that the majority of chorion deposition occurs in the midregion of the uterus, where vast networks of endoplasmic reticulum are present in the columnar epithelium. Expand
Evidence for cell turnover as the mechanism responsible for the transport of embryos towards the vagina in viviparous onychophorans (velvet worms)
TLDR
The results confirm the hypothesis that the uterus of placentotrophic onychophorans grows proximally but is resorbed distally, and suggest that the distal degenerative zone is an ancestral feature of OnyChophora, whereas the proximal proliferation zone might have evolved in the last common ancestor of the placentOTrophic Peripatidae. Expand
Seminal receptacula in gravid and virgin female Peripatus (Macroperipatus) acacioi Marcus and Marcus (Onychophora, Peripatidae)
TLDR
Observations of the structure of the seminal receptaculum using transmission electron microscopy (TEM) show that there are numerous tracheae within its wall indicating a good oxygen supply, and the ultrastructure of the epithelium lining the seminal conduit indicates that these cells secrete the material that forms the luminal matrix that surrounds and provides nutrition for the stored spermatozoa. Expand
Early development in the velvet worm Euperipatoides kanangrensis Reid 1996 (Onychophora: Peripatopsidae)
TLDR
The data support the view of a blastopore that becomes elongated and slit-like, resembling some of the earliest descriptions, and it is concluded that the position of the proctodeum is the most posterior pit in the developing embryo. Expand
First ultrastructural evidence of placental nutrition in a ctenostome bryozoan: example of Amathia verticillata
TLDR
An ultrastructural approach is used to report the first evidence of placentation in the ctenostome bryozoan Amathia verticillata, a marine colonial suspension-feeder that incubates its progeny in the tentacle sheath, which is transformed into a brood chamber. Expand
Ultrastructure of mesoderm in embryos of Opisthopatus roseus (Onychophora, Peripatopsidae): Revision of the “long germ band” hypothesis for Opisthopatus
TLDR
No evidence in support of a “long germ band” hypothesis in Opisthopatus was found, and the embryogenesis in representatives of Opistshopatus is more similar to that in other onychophorans than expected. Expand
Differential life‐history characteristics of male and female Peripatoides novaezealandiae (Onychophora: Peripatopsidae)
TLDR
Life-history details of the live-bearing Peripatoides novaezealandiae (Hutton) were obtained by measuring and dissecting field collected animals, and sex-specific weight frequency distributions and regression of weight vs length suggest sex differences in patterns of growth and/or mortality. Expand
Three in one: evolution of viviparity, coenocytic placenta and polyembryony in cyclostome bryozoans
TLDR
It is speculated that the acquisition of a highly advanced placenta providing massive nourishment might support the evolution of polyembryony in cyclostomes, the only known example of a coenocytic placental analogue of this type in animals. Expand
...
1
2
3
...

References

SHOWING 1-10 OF 10 REFERENCES
Some aspects of segment formation and post‐placental development in Peripatus acacioi marcus and marcus (Onychophora)
The surface morphology of the anterior‐to‐posterior sequence of segment formation in embryos of a viviparous neotropical onychophoran and aspects of post‐placental development seen using scanningExpand
Seminal receptacula in the female reproductive tract of Opisthopatus cinctipes purcell (onychophora, peripatopsidae)
  • M. Walker
  • Biology, Medicine
  • Journal of morphology
  • 1992
TLDR
It is suggested that these cells absorb those spermatozoa not required for fertilization, and that the seminal receptacula in the Peripatopsidae act as short‐term storage sites for spermatozosa. Expand
Studies on the Onychophora VIII. The relationship between the embryos and the oviduct in the viviparous placental onychophorans Epiperipatus trinidadensis Bouvier and Macroperipatus torquatus (Kennel) from Trinidad
TLDR
The present study provides the first detailed account of the formation and structure of the placentation zone in the neotropical Onychophora and of the events involved in the movement of the embryos along the oviduct. Expand
Studies on the Onychophora. IV. The Passage of Spermatozoa into the Ovary in Peripatopsis and the Early Development of the Ova
TLDR
In some species of Onychophora, notably most of the Peripatopsidae, the male deposits small spermatophores anywhere on the body surface of the female, and the receptacula seminis are almost or completely absent, and spermatozoa are found in the lumen of the ovarian tubes. Expand
Relatively recent evolution of an unusual pattern of early embryonic development (long germ band?) in a South African onychophoran, Opisthopatus cinctipes Purcell (Onychophora: Peripatopsidae)
TLDR
Allozyme analysis indicates that O. cinctipes diverged from the other South African genus Peripatopsis Pocock, with in the last 30 Myr, and indicates that mesodermal somites formed after elongation has occurred. Expand
Parental investment and sex allocation in a viviparous onychophoran
TLDR
There was considerable overlap in the size distributions of freeliving juveniles and embryos, indicating that the period of embryonic care is variable, and there was a positive correlation between embryo and maternal size, suggesting that large females release larger offspring which can more quickly attain maturity. Expand
A morphometric study of the tracheal system of Peripatus acacioi Marcus and Marcus (Onychophora).
TLDR
There appears to be a positive correlation between tracheal surface density and tissue metabolic activity in Peripatus acacioi Marcus and Marcus (Onychophora). Expand
Studies on the Onychophora. II. The Feeding, Digestion, Excretion, and Food Storage of Peripatopsis with Biochemical Estimations and Analyses
TLDR
The material for this work consisted of several hundred specimens of Peripatopsis obtained in South Africa in 1933 and brought to England alive and used as extensively as possible for other purposes. Expand