Differential reproductive timing in Echinocardium spp.: The first Mediterranean survey allows interoceanic and interspecific comparisons

Emilie Egea (1) , Bastien Merigot (1) , Chantal Mahe-Bezac (1) , Jean-Pierre Féral (1) , Anne Chenuil (1)

1 DIMAR - Diversité, évolution et écologie fonctionnelle marine

Echinocardium cordatum had long been considered as cosmopolitan, but molecular data revealed it is a complex of cryptic species, with two non-hybridizing species (B1 & B2) in the Mediterranean Sea living in syntopy with Echinocardium mediterraneum. Histological analyses of the gonads from a 17-month sampling period revealed a statistically significant time lag between the Maturity Indices of E. cordatum and E. mediterraneum. The main environmental stimulus may be different for the two nominal species, possibly seawater temperature for E. cordatum and chlorophyll a concentration for E. mediterraneum. Within the E. cordatum complex, spawning timing and synchrony are different according to major geographic areas (Atlantic/Pacific/Mediterranean) and/or the corresponding genetic subdivision [A/P/(B1 & B2)]. In contrast, the effects of temperature on the reproductive cycle seem rather to mirror the genetic lineages than environmental similarities of the different localities. Between the sister species (B1 & B2) no differences could be detected, maybe due to small sample sizes. (c) 2010 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.

Domaines: Planète et Univers [physics]; Océanographie

Emilie Egea, Bastien Merigot, Chantal Mahe-Bezac, Jean-Pierre Féral, Anne Chenuil. Differential reproductive timing in Echinocardium spp.: The first Mediterranean survey allows interoceanic and interspecific comparisons. Comptes Rendus Biologies, 2011, 334 (1), pp.13-23. ⟨10.1016/j.crvi.2010.10.007⟩. ⟨hal-01631355⟩