The calcium and phosphate metabolism of reproducing reptiles with particular reference to the adder (vipera berus)

Jenkins, N.; Simkiss, K.

doi:10.1016/0010-406x(68)90006-6

Cited by 37 publications

(15 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Among marine turtles, reports on calcium and other mineral components are available for green (Jenkins and Simkiss, 1968;Solomon and Baird, 1977), leatherback (Solomon and Watt, 1985;Schleich and Kastle, 1988), and olive ridley turtles (Sahoo et al, 1998). The chemical compositions of unfertilized eggshells of olive ridley turtles are within the range reported for fertile eggs of marine turtles.…”

mentioning

confidence: 84%

“…The amount of calcium varies greatly among species of reptiles. Calcium is the principal inorganic mineral in the yolk-albumen fraction of eggs of squamates (Jenkins and Simkiss, 1968;Cox et al, 1984;Packard et al, 1992;Osborne and Thompson, 2005), crocodiles (Jenkins, 1975), fresh water turtles (Karashima, 1929;Miller and Jones, 1990;Packard and Packard, 1991), and marine turtles (Tomita, 1929;Simkiss, 1962;Solomon and Baird, 1976;Chan and Solomon, 1989). Minerals other than calcium e.g., magnesium, potassium, and sulphur, are present in trace or just above trace levels in the eggshell (Solomon and Baird, 1976;Chan and Solomon, 1989) and yolkalbumen (Sahoo et al, 1998).…”

mentioning

confidence: 97%

See 1 more Smart Citation

Chemical Composition and Ultrastructure of Shells of Unfertilized Eggs of Olive Ridley Turtles, Lepidochelys olivacea

Sahoo

Mohapatra

Dutta

2010

Current Herpetology

View full text Add to dashboard Cite

mentioning

confidence: 84%

mentioning

confidence: 97%

Chemical Composition and Ultrastructure of Shells of Unfertilized Eggs of Olive Ridley Turtles, Lepidochelys olivacea

Sahoo

Mohapatra

Dutta

2010

Current Herpetology

View full text Add to dashboard Cite

“…This model gained support from early speculation on patterns of embryonic calcium nutrition. An assumption that eggshells of squamates contained little calcium, in conjunction with an observation that the yolk of squamates is rich in calcium, led to the paradigm that squamates differ from other reptiles in that yolk is the sole source of calcium for development (Simkiss, ; Jenkins and Simkiss, ). This concept was an important premise for a prominent model of the evolution of reptilian viviparity (Packard et al, ), which promoted further the concept that the transition between oviparity and viviparity did not require replacement of lost nutrients.…”

Section: Embryonic Calcium Nutritionmentioning

confidence: 99%

Placental specializations in lecithotrophic viviparous squamate reptiles

Stewart

2015

J Exp Zool Pt B

View full text Add to dashboard Cite

Squamate reptiles have been thought to be predisposed to evolution of viviparity because embryos of most oviparous species undergo considerable development in the uterus prior to oviposition. A related hypothesis proposes that prolonged intrauterine gestation, an intermediate condition leading to viviparity, requires little or no physiological adjustment, other than reduction in thickness of the eggshell. This logical framework is often accompanied by an assumption that mode of parity (oviparity, viviparity) and pattern of embryonic nutrition (lecithotrophy, placentotrophy) are independent traits that evolve in sequence. Thus, specializations for viviparity should be absent in some lecithotrophic viviparous species. Studies of species of lizards with geographic variation in mode of parity challenge this scenario by demonstrating that placental specializations are correlated with viviparity. Uterine specializations for placental transport of calcium to viviparous embryos alter uterine physiology compared to oviparous females. In addition, comparative studies of oviparous and viviparous species, i.e., in which gene flow is disrupted, reveal that both uterine and embryonic structural modifications are commonly associated with viviparity, suggesting relatively rapid evolution of placental specializations. Studies of squamate reproductive biology support two hypotheses: 1) evolution of viviparity requires physiological adjustments of the uterine environment, and 2) evolution of viviparity promotes relatively rapid adaptations for placentation. Models for the evolution of viviparity from oviparity, or for reversals from viviparity to oviparity, should reflect current understanding of squamate reproductive biology and future studies should be designed to challenge these models.

show abstract

“…These processes were extensively studied in birds (synthesis in Dacke, 1979), but information about reptiles is meagre (see e.g. Jenkins & Simkiss, 1968), and mainly deals with crocodilians (Elsey & Wink, 1985;Wink & Elsey, 1986;Wink, Elsey & Hill, 1987; see also Hutton, 1986) and turtles (Edgren, 1960;Suzuki, 1963;Iverson, 1982), two groups distinct from most other reptiles by the production of eggs with heavily calci®ed shells.…”

Section: Introductionmentioning

confidence: 99%

“…Packard & DeMarco, 1991; see also Stewart, 1997). Conversely, squamate yolk contains much more calcium than that of birds and turtles (Jenkins & Simkiss, 1968). Moreover, female reproductive output in some taxa can reach high levels, as typically exempli®ed by some monitor lizards (de Buffre Ânil & Rimblot, 1999): in Varanus niloticus, a highly exploited African species, clutch mass in young adult females can represent > 60% of net body mass (body mass after removal of the eggs).…”

Section: Introductionmentioning

confidence: 99%

Ontogenetic changes in bone compactness in male and female Nile monitors (Varanus niloticus)

Buffrénil

Francillon‐Vieillot

2001

Journal of Zoology

View full text Add to dashboard Cite

The compactness of bone tissue was measured in the shaft of the femur, tibia and ®bula in 390 male and female Nile monitors Varanus niloticus from three distinct regions of Sahelian Africa. In males, bone compactness increases during ontogeny in the three bones. Conversely, in females, it tends to decrease in the femur and, to a lesser extent, the tibia, but not in the ®bula. In addition to this long-term trend, gravid females have lower femoral compactness than mature non-gravid ones. Moreover, important differences are noticeable between local samples, indicating that the variation in bone compactness during ontogeny is a¯exible or even a facultative process. Histological observations reveal the existence of an extensive remodelling by resorption and reconstruction on the walls of the marrow cavity in the femur and tibia, and the complete absence of Haversian substitution. It is concluded from these data that: (1) during ovogenesis, female Nile monitors recycle skeletal calcium through cortical resorption in certain bones, if the calcium supply from food is not enough; (2) this remodelling process is not balanced, which creates a long-term tendency towards a de®cit in reconstructive bone, and a consecutive decrease in the compactness of the skeletal elements involved. The comparative and functional aspects of these results are discussed.

show abstract

The calcium and phosphate metabolism of reproducing reptiles with particular reference to the adder (vipera berus)

Cited by 37 publications

References 9 publications

Chemical Composition and Ultrastructure of Shells of Unfertilized Eggs of Olive Ridley Turtles, Lepidochelys olivacea

Chemical Composition and Ultrastructure of Shells of Unfertilized Eggs of Olive Ridley Turtles, Lepidochelys olivacea

Placental specializations in lecithotrophic viviparous squamate reptiles

Ontogenetic changes in bone compactness in male and female Nile monitors (Varanus niloticus)

Contact Info

Product

Resources

About