Thursday, 14 April 2016

Placentation in the Tasmanian bettong

Tasmanian bettong (Bettongia gaimardi cuniculus)
By JJ Harrison (CC BY-SA 3.0) via Wikimedia Commons
Now regarded as a subspecies of Eastern bettong (the mainland subspecies is extinct), the fetal membranes of this small kangaroo were described in 1930 by Theodore Thomson Flynn.

Trilaminar omphalopleure (vascular yolk sac) of Tasmanian bettong
From Flynn Proc Linn Soc NSW 1930; 55: 506-531
The yolk sac comprises a vascular portion (trilaminar omphalopleure) and a non-vascular portion (bilaminar omphalopleure). The sketch above shows trophoblast of the vascular yolk sac (troph) absorbing secretions from a uterine gland (gl ep). It is unclear whether there is exchange between the capillaries on the maternal (m cap) and fetal (foet cap) sides.
Bilaminar omphalopleure (non-vascular yolk sac) of Tasmanian bettongFrom Flynn Proc Linn Soc NSW 1930; 55: 506-531
Trophoblast of the non-vascular yolk sac (bilaminar omphalopleure) was implicated in the uptake of cellular material (cm) and red blood cells (haem). In current terminology (here) it is heterophagous.

Theodore Thomson Flynn (right) with his son the actor Errol Flynn
Theodore Thomson Flynn was a marine biologist and professor at the University of Tasmania. He named a fish Gibbonsia erroli after his son Errol Flynn the film actor.

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