Abnormal persistence of the chorioallantoic membrane is associated with severe developmental abnormalities in freshwater turtles

We described a previously unreported developmental anomaly: the retention of an extra-embryonic membrane around 7 turtles (1 Spiny Softshell Turtle (Apalone spinifera (Le Sueur, 1827)), 1 Snapping Turtle (Chelydra serpentina (Linnaeus, 1758)), and 5 Northern Map Turtles (Graptemys geographica (Le Sueur, 1817))) that were alive but unhatched>14 days after their clutch mates had emerged. We investigated the association between retention of this membrane and the exhibition of other developmental deformities of varying severity, and we tested whether this novel abnormality was associated with reduced fertility or hatching success in affected clutches. Consultation of ∼150 years of literature suggests that we observed persistence of the chorioallantoic membrane (CAM; also called the chorioallantois). Our data suggest that clutches where at least one turtle exhibits a persistent CAM may also exhibit slightly reduced fertility or hatch success in the rest of the clutch compared with conspecific clutches that do not contain this anomaly. Future research should investigate the factors predicting CAM retention and other developmental abnormalities.
Source: Canadian Journal of Zoology - Category: Zoology Authors: Source Type: research