Morphology and development of the placentae in Eulamprus quoyii group skinks (Squamata: Scincidae)

  title={Morphology and development of the placentae in Eulamprus quoyii group skinks (Squamata: Scincidae)},
  author={Bridget F. Murphy and Matthew C. Brandley and Christopher R. Murphy and Michael B. Thompson},
  journal={Journal of Anatomy},
Frequent evolutionary changes in reproductive mode have produced a wide range of placental structures in viviparous squamate reptiles. Closely related species with different placental structures and resolved phylogenetic relationships are particularly useful for reconstructing how placentae might have transformed during the evolutionary process. We used light microscopy to study placental morphology in mid‐ to late stage embryos of four closely related species of Eulamprus, a genus of… 

Uterine and eggshell modifications associated with the evolution of viviparity in South American water snakes (Helicops spp.)

The hypothesis that eggshell thinning is associated with the evolution of viviparity and that such thinning result from a reduction in gland size in vivIParous taxa is supported.

The evolution of viviparity: molecular and genomic data from squamate reptiles advance understanding of live birth in amniotes.

Squamate reptiles (lizards and snakes) are an ideal model system for testing hypotheses regarding the evolution of viviparity (live birth) in amniote vertebrates, and studies of the emergence of v Viviparity in squamates should inform hypotheses of the evolution in all amniotes, including mammals.

Changes to the uterine epithelium during the reproductive cycle of two viviparous lizard species (Niveoscincus spp.)

Investigation of morphological differences in uterine epithelia of the reproductive cycle between two closely related viviparous skinks revealed that the uterine surface of non-reproductive females of both species is mainly covered by ciliated cells.

A developmental synapomorphy of squamate reptiles

Given its absence in mammals, chelonians, crocodylians, and birds, the YC–IYM complex warrants recognition as a developmental synapomorphy of the squamate clade.

Early origin of viviparity and multiple reversions to oviparity in squamate reptiles.

This work reconstructs ancestral parity modes accounting for state-dependent diversification in a large-scale phylogenetic analysis and finds strong support for an early origin of viviparity at the base of Squamata, and a complex pattern of subsequent transitions.

Ovoviviparous reproduction in Australian specimens of the intertidal isopod Cirolana harfordi

Cirolana harfordi in Australia is, therefore, displaying ovoviviparous reproduction and not incubation in a marsupial pouch external to the pereon as previously thought.

A Comparison of Placental Tissue in the Skinks Eulamprus tympanum and E. Quoyii

The species Eulamprus tympanum and Eulamprus quoyii are viviparous skinks that are said to have a Type I placenta. This research compared histological characteristics of the oviduct during pregnancy

Reparative processes in jaw bones under using of different plastic materials.

The comparative experimental morphological and histomorphometric studies of the bone regeneration involving the replacement of created jaw defects with osteoplastic material Kergap-T alone and in the combination with the lyophilized biological placenta implant Osteopor proved that the latter speeded up the beginning of active regenerative processes promoting the early defect filling with the neogenic organotypic osseous tissue.

Evolution & Development

  • 2019

Placental specializations in lecithotrophic viviparous squamate reptiles.

  • J. R. Stewart
  • Biology
    Journal of experimental zoology. Part B, Molecular and developmental evolution
  • 2015
Comparative studies of squamate reproductive biology reveal that both uterine and embryonic structural modifications are commonly associated with viviparity, suggesting relatively rapid evolution of placental specializations.



Evolution of reptilian placentation: Development of extraembryonic membranes of the Australian scincid lizards, Bassiana duperreyi (Oviparous) and Pseudemoia entrecasteauxii (Viviparous)

A revision of a classic model for the evolution of placentation among Reptilia, which predicts specific relationships among reproductive characteristics and thus is testable by comparative analysis among other species within the Eugongylus group of Australian skinks.

Placental ontogeny in Tasmanian snow skinks (genus Niveoscincus) (Lacertilia: Scincidae)

Light microscopy is used to study placental ontogeny in two biennially reproducing species of Niveoscincus and placental morphology in late stage embryos of N. pretiosus, providing descriptions of placental structure for six of the eight species assigned to this lineage.

Placental ontogeny of the Tasmanian scincid lizard, Niveoscincus ocellatus (Reptilia: Squamata)

A prominent scenario for the evolution of reptilian placentation infers that placentotrophy arose by gradual modification of a simple vascular chorioallantoic placenta to a complex structure with a

Morphogenesis of placental membranes in the viviparous, placentotrophic lizard Chalcides chalcides (Squamata: Scincidae)

The discovery of five distinct placental arrangements in this species, three of which are transitory and two of which have not been recorded in reptiles, emphasizes the need for accounts that specify ontogenetic stages and the precise identity and composition of squamate placental membranes.

Evolutionary transformations of the fetal membranes of viviparous reptiles: a case study of two lineages.

This work compared extraembryonic membrane and placental development and pattern of embryonic nutrition in thamnophiine snakes and Pseudemoia lizards in the context of recent hypotheses of phylogenetic relationships and found two primary types of placentation, chorioallantoic and yolk sac, evolved in each lineage.

Placental structure of the Australian lizard, Niveoscincus metallicus (Squamata: Scincidae)

A unique type of reptilian allantoplacenta was described by Weekes [1930] from a single embryonic stage of the Tasmanian skink, Niveoscincus ocellatus (as Lygosoma (Liolepisma) ocellatum) and assigned N. metallicus to this placental category but did not provide a description.

Placentation in the eastern water skink (Eulamprus quoyii): a placentome‐like structure in a lecithotrophic lizard

The description of uterine morphology in E. quoyii provides evidence that, at least in some lineages, the evolution of a placentome may not occur in concert with the evolutionof microlecithal eggs and obligate placentotrophy.

Placental ontogeny of the Australian scincid lizards Niveoscincus coventryi and Pseudemoia spenceri.

Comparison of extraembryonic membrane and placental structure among the four viviparous and one oviparious species of Eugongylus group skinks for which data are available shows that each species exhibits characters that distinguish it from other species, while additional characters are shared among all, or some, species.

Histology of the late‐stage placentae in the matrotrophic skink Chalcides chalcides (Lacertilia; Scincidae)

Morphologically, the mature placentae of C. chalcides are among the most specialized to have been described in reptiles, reflecting the substantial maternal‐fetal nutrient transfer that occurs in this species.

Yolk sac placentation in reptiles: Structural innovation in a fundamental vertebrate fetal nutritional system

The yolk sac of viviparous reptiles contributes to three categories of placentation, the choriovitelline placenta, which also occurs in marsupial and eutherian mammals, and the Omphaloplacenta and omphalallantoic placentA, which occur only among squamate reptiles (lizards and snakes).