Chorion surface features of chelicerate eggs

WA Museum Records and Supplements | Updated 1 decade ago

Abstract: The chorion surface features of the eggs of various orders and suborders of chelicerates are compared. Eggs of the suborder Mesothelae have spheres coating the chorion surface as found in the other Araneae suborders. Hence, all Araneae eggs examined have had a surface coating of spheres. Some Ricinulei eggs are coated with spheres comparable to those found in the Araneae but they are not sister groups. No other chelicerate eggs examined have surfaces coated with spheres comparable to those found in the Araneae. These include the Schizomida, Pseudoscorpionida, Uropygi, Amblypygi, Opiliones, Acari, Xiphosura and Pycnogonida. These other orders have different features on the egg surface ranging from a lack of ornamentation, through sculptured surfaces, to honeycomb structures or fibrous networks. The presence of a layer of spheres on a ricinuleid egg similar to those found on the eggs of spiders needs confirmation as there is a chance that a spider's egg was being carried by the ricinuleid when it was collected.