Embryonic development of the false limpet Siphonaria lateralis from Atlantic Patagonia

ZABALA, SOLEDAD; AVERBUJ, ANDRÉS; BIGATTI, GREGORIO; PENCHASZADEH, PABLO E.

INVERTEBRATE BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2020 vol. 139

1077-8306

Siphonariids are pulmonate gastropods inhabiting rocky intertidal habitats, andmany studies have focused on these false limpets around the world. In the southernSouth Atlantic, studies on reproduction and development in species of Siphonariaare scarce. We studied the embryonic development and egg masses of Siphonarialateralis at its northernmost distribution in Atlantic Patagonia. In S. lateralis, as in mostspecies of Siphonaria, individuals spawn benthic egg masses that strongly attach tointertidal rocky substrata. A single spherical egg that measures ~120 μm developsinside the egg capsule of S. lateralis. Considering the relatively small egg size, andreports from previous studies, the developmental modality of S. lateralis might beexpected to include a planktotrophic larval phase. However, we found that hatchlingsemerged as 1-mm crawling juveniles, probably owing to the presence of intracapsularfluid, which may provide the energetic requirements for direct development. The embryonicsize changed little from the egg to veliger stages, and then increased rapidlyuntil the hatchling stage. We compared development in S. lateralis with developmentin the sympatric Siphonaria lessonii, in which egg size was reported to be ~80 μmand hatching occurs as planktotrophic veliger larvae. In these two species, spawnand early intracapsular developmental modes are remarkably different; these differencesrepresent contrasting ways to survive in the harsh and physically stressfulintertidal Patagonian coasts.