Intracapsular embryogenesis and larval development of Chicoreus ramosus (Linnaeus, 1758) and Dendropoma platypus (Mörch, 1861) (Gastropoda, Prosobranchia) under normal and treated conditions

Abstract Samples of C. ramosus and D. platypus were collected from Hurgada, the Red Sea during June-August 2018. Samples were transported to the lab at the University of Alexandria, Egypt. This study aims to describe the embryogenesis of C. ramosus inside the capsules and test the effects of signaling factors and neuro-transmitters on the in vitro transformation of larvae of D. platypus and identify some bioactive inducers that increase larval metamorphosis. Capsules of C. ramosus were fixed in 10% saline formaldehyde and capsules of D. platypus were placed in plastic aquaria for immune-histochemical test. The sequence of the embryonic transformations and the duration time of each step of C. ramosus were identified. The importance of the following experiment is to provide a suitable medium for the developing larval stages and improve eugenic manner of the new generations. Undertreated conditions of D. platypus larvae, MF 2.5 mM, C8:0 1 µM, ADMA 2.5 mM, and Acetylcholine 0.5 mM larval transformation from trochophore to veliger to early juvenile stages was accelerated than larvae of control in seawater. Serotonin 10 µg/ml and Acetylcholine 1 mM exerted a negative effect while C8:0 0.1 or 10 µM, MF 300 µM, ADMA 1 mM and 1.5 mM did not affect larval transformation. Atorvastatin (5, 20 and 40 mg), Pravastatin (50 mg and 100 mg), Cetirizine hydrochloride (10 mg), Nebivolol (2.5 mg, 5 mg. and 10 mg), Atenolol (25 mg and 100 mg) and Amlodipine Besylate (2.5 mg, 5.0 mg, and 10 mg) exerted a negative impact on larvae in all stages and mortality predominated.