Reproductive features in the sea cucumber Pentactella perrieri (Ekman, 1927) (Holothuroidea: Cucumariidae): a brooding hermaphrodite species from the southwestern Atlantic Ocean

Abstract

Cucumariidae (Echinodermata: Holothuroidea) is a family of sea cucumbers known for displaying different reproductive strategies, including brooding and hermaphroditism. These reproductive strategies of marine invertebrates are a key feature, since it is strongly related to evolutionary and ecological aspects. According to the place in which offsprings are grown, brooding can be classified in six groups, underneath the ventral sole, among tentacles, brood pouches, dorsal pockets, perivisceral coelom and in the ovary. The last two groups are restricted to a few studied cucumariids, with only one previous report for the southwestern Atlantic Ocean. Specimens of Pentactella perrieri along its known distribution (including Burdwood Bank/MPA Namuncurá and Subantarctic area) were analyzed, using morphological observations of the internal and external features. We found for the first time, that P. perrieri is a hermaphroditic species identified as a brooder. We found between 7 up to 11 brooded individuals, of up to 3 mm length, inside of 2 thin spherical and transparent brood-sacs, with a ventral external opening. Oocytes up to 1600 µm were found in May, being the largest known for the family. It was also the month with the largest mean oocytes size (778.38 ± 611.40 µm, N = 2). This research contributes to the study of the many different reproductive strategies that marine invertebrates can adopt.