This is the time when mammalian viviparity
had begun and two different types of viviparous systems using chorioallantoic and choriovitelline (yolk sac) placentas were established in the eutherians and marsupials, respectively (Figs.
When reptiles initially moved to colder areas they needed to evolve emergency measures to succeed in these harsh places, and we believe viviparity
is one of these key measures.
New record of viviparity
for the dominant benthic invertebrate Exogone hebes (Polychaeta: Syllidae) from the Grand Banks of Newfoundland.
A cost of viviparity
and parental tare in scorpions: Reduced sprint speed and behavioural compensation.
The small, oval fruit rarely shows viviparity
. The seed generally falls and sprouts a root within a few days.
To illustrate the breadth of his curiosity-driven insight, consider the following titles of papers he published with co-authors: i) The spiral in the tusk of the narwhal (1988, Arctic 41:236-238); ii) Constraints on brain growth (1989, Nature 340:194); iii) The evolution of viviparity
in amniotes: egg retention vs.
Thermal consequences of reptilian viviparity
: thermoregulation in gravid and nongravid garter snakes (Thamnophis).
If Hozukius is found to be viviparous like Sebastes and Sebastiscus, then viviparity
would be another derived character to support this subfamily.
Reconstructing ancestral reaction norms: an example using the evolution of reptilian viviparity
. Functional Ecology 10:688-697.
and population genetics of Actinia tenebrosa.
is the reproductive strategy of these fishes (Koya et al., 2000).
Thermal and reproductive biology of high and low elevation populations of the lizard Sceloporus scalaris: implications for the evolution of viviparity
. Oecologia 104:101-111.