Reproductive and Fat Body Cycles of the Viviparous Lizard, Sceloporus mucronatus (Sauria: Iguanidae)

Delacruz, Frm; Guillette, L. J.; Cruz, M. Villagran-Santa; Casas-Andreu, Gustavo

doi:10.2307/1564351

Cited by 63 publications

(33 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The chorioallantoic membrane is the only vascularized embryonic structure in close apposition to the uterus from embryonic Stage 29 to parturition. Embryonic growth of S. mucronatus is greatest during this developmental interval (Méndez-de la Cruz et al, 1988) and presumably this is a time of peak respiratory demand. The degeneration of the shell membrane in association with the chorioallantoic placenta further reduces the diffusion distance between maternal and embryonic blood streams.…”

Section: Placental Functionmentioning

confidence: 99%

“…Placental nutrient provision has not been studied in Sceloporus mucronatus but most nutrients are provided by the large yolk mass because dry mass of late-stage embryos is 19% lower than recently ovulated eggs (Méndez-de la Cruz et al, 1988). However, placental transfer of water is significant because wet mass of late stage embryos is 268% higher than recently ovulated eggs (Méndez-de la Cruz et al, 1988).…”

Section: Placental Functionmentioning

confidence: 99%

“…However, placental transfer of water is significant because wet mass of late stage embryos is 268% higher than recently ovulated eggs (Méndez-de la Cruz et al, 1988). There is a 20% increase in wet mass from ovulation to embryonic Stages 30 -32 and eggs more than double in wet mass from then to the final embryonic stage.…”

Section: Placental Functionmentioning

confidence: 99%

“…Females exhibit maximal gonadal activity during late summer and fall, are pregnant during the winter, and give birth the following spring (Méndez-de la Cruz et al, 1988;Estrada et al, 1990). We studied the ontogeny of placentation of S. mucronatus during 6 months of gestation (November-May) as a contribution to understanding the evolution of viviparity and placentation within the genus Sceloporus and to better understand variation in placental development among squamate reptiles.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Placentation in the Mexican lizard Sceloporus mucronatus (Squamata: Phrynosomatidae)

Villagrán

Méndez

Stewart

2005

Journal of Morphology

View full text Add to dashboard Cite

We used light microscopy to study placental structure of the lizard Sceloporus mucronatus throughout 6 months of embryonic development. Three stages of placental development could be assigned to embryos based on the arrangement of the extraembryonic membranes. A highly vascular choriovitelline placenta was present in the embryonic hemisphere and a nonvascular bilaminar omphalopleure covered most of the abembryonic hemisphere of the egg during embryonic Stages 10-28. A chorioallantoic placenta replaced the choriovitelline placenta by embryonic Stage 29 and an omphaloplacenta covered the abembryonic hemisphere at this stage. The combination of these two placental types occurred in Stage 29-36 embryos. The final stage of placentation, embryonic Stages 37-40, was characterized by an omphalallantoic placenta in the abembryonic hemisphere and a chorioallantoic placenta in the embryonic hemisphere of the egg. The choriovitelline and chorioallantoic placentae are well vascularized, with closely apposed maternal and embryonic blood vessels. These structures are the most likely sites of respiratory exchange. In contrast, the omphaloplacenta and omphalallantoic placentae contain cuboidal or columnar epithelia and these structures may function in histotrophic exchange. Placentation of S. mucronatus is similar to that of predominantly lecithotrophic species in other squamate lineages suggesting that the evolution of this placental morphology is a response to similar factors and is independent of phylogeny.

show abstract

Section: Placental Functionmentioning

confidence: 99%

Section: Placental Functionmentioning

confidence: 99%

Section: Placental Functionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Placentation in the Mexican lizard Sceloporus mucronatus (Squamata: Phrynosomatidae)

Villagrán

Méndez

Stewart

2005

Journal of Morphology

View full text Add to dashboard Cite

show abstract

“…In most studies, the acquisition of energy and its allocation to life history parameters has been determined by sacrificing individuals taken from populations and calculating average clutch and egg size (e.g. Shine, 1983;Jones and Ballinger, 1987;Mendez de la Cruz et al, 1988;Ramirez-Bautista and Olvera-Becerril, 2004). Then, data were usually combined with data on the age at first breeding, instantaneous mortality, and growth rates to test predictions from life history theory and trade-off models (e.g.…”

Section: Introductionmentioning

confidence: 99%

Use of portable ultrasonography as a nondestructive method for estimating reproductive effort in lizards

Gilman

Wolf

2007

Journal of Experimental Biology

View full text Add to dashboard Cite

SUMMARY Obtaining population-level life history data such as egg and clutch size in reptiles has most often required that individuals be sacrificed. This prevents a reexamination of individuals over intra-annual and inter-annual time scales,limiting insight into the effects of varying environmental conditions on reproductive output. Here, we test the use of a laptop-sized portable ultrasound imaging system as a nondestructive means for quantifying reproductive investment in five species of lizards with a range of body sizes,forms and life histories. Ultrasound scans produced egg counts that were accurate for clutch sizes of two to seven eggs, and provided good estimates(within 5.5±1.69 eggs, mean ± s.e.m., relative error 21%) for clutch sizes of between 18 and 41 eggs. Egg measurements using virtual calipers produced average egg volumes that deviated from actual volumes by 0.09±0.01 cm3 (relative error 25.9%), and estimated clutch volumes that differed from actual volumes by 1.03±0.26 cm3(relative error 29.5%). We also monitored development in five lizard species and found that changes in follicle and egg size and degree of embryonic development can be measured over periods of just a few days.

show abstract

Fat body ovarian relationship in the garden lizard, Calotes versicolor (Daud.)

Shanbhag

1992

J. Exp. Zool.

View full text Add to dashboard Cite

Abdominal fat body mass of Calotes versicolor showed annual changes that were universal related to the changes in ovarian somatic (GSI) and hepatosomatic (HSI) indices. Fat bodies were absent in late breeding phase (June-August). Thirty day fatectomy (FBX) during prebreeding phase significantly reduced GSI, HSI, and total number of extrastromal follicles; also, recruitment of vitellogenic follicles was arrested and ateretic follicles increased. The FBX during postbreeding phase had no such effect, whereas in 30 day ovariectomised (OvX) lizards in prebreeding phase fat body mass significantly increased but HSI decreased. However, in lizards in prebreeding phase, E2 caused a significant decrease in fat body mass and an increase in HSI, while during the postbreeding phase there was a significant increase in HSI but the fat bodies were not affected. The above findings suggest that the development of the first clutch of vitellogenic follicles in the lizard utilises lipids stored in the fat bodies and that the growth of the subsequent clutches of vitellogenic follicles is met through the intake of food, which is abundant in the latter part of the breeding phase. The fat bodies are not needed for the growth of previtellogenic follicles. The fact that lipolytic action of E2 occurs only during the breeding phase suggests that responsiveness of the fat bodies to the steroid is related to the reproductive phase and that during postbreeding phase of the lizard they become refractory to E2.

show abstract

Reproductive and Fat Body Cycles of the Viviparous Lizard, Sceloporus mucronatus (Sauria: Iguanidae)

Cited by 63 publications

References 21 publications

Placentation in the Mexican lizard Sceloporus mucronatus (Squamata: Phrynosomatidae)

Placentation in the Mexican lizard Sceloporus mucronatus (Squamata: Phrynosomatidae)

Use of portable ultrasonography as a nondestructive method for estimating reproductive effort in lizards

Fat body ovarian relationship in the garden lizard, Calotes versicolor (Daud.)

Contact Info

Product

Resources

About