Larval dispersion of the commensal nemertean Malacobdella arrokeana in North Patagonics gulfs, Argentina

FERNÁNDEZ ALFAYA, JOSÉ E.; BIGATTI GREGORIO; PABLO E. PENCHASZADEH; TONINI MARIANO

Sylt

Congreso; 9th International Conference of Nemertean Biology; 2018

Universidad de Bonn

The nemertean Malacobdella arrokeana is a commensal of the edible giant bivalve Panopea abbreviata; both species have arestricted geographic distribution, high specificity and populations separatedby natural barriers. This supposes a high genetic structuring among populationsand low intra-populational variability; nevertheless, a lack of genetic structurewas detected previously between M.arrokeana populations from Atlantic norpatagonic gulfs using mitochondrialand nuclear markers. Here, we present the first attempt to explain this lack ofgenetics structure, integrating larval behavior and bio-oceanographical modelsimulations (ROMS) which corroborate that the population genetic results are inconcordance with particle dispersion model simulation. Cultured larvae obtainedhad a mean planktonic life of 30 days after fertilization. Larval morphology (planuliform)and behavior suggest that the dispersion is influenced by passive transport relatedto season and hydrodynamic diffusion patterns present in the area. Our resultsare useful to understand the dispersion and settlement of larvae along the northPatagonic gulfs and provides novel baseline data in larval connectivity andoceanographic circulation patterns.