Phylogenetic relationships, origin and historical biogeography of the genus (Clupeiformes: Clupeidae).

The genus comprises five species of marine pelagic fishes distributed worldwide in antitropical, temperate waters. Their distribution suggests an ancient origin during a cold period of the earth's history. In this study, we evaluated this hypothesis and corroborated the non-monophyly of the genus , using a phylogenetic approach based on DNA sequences of five mitochondrial genome regions.

Ingestion of contaminated kelps by the herbivore Tetrapygus niger: Negative effects on food intake, growth, fertility, and early development.

Macrocystis pyrifera reaches distant areas after detachment, accumulate heavy metals, and serve as trophic subsidy. In this context, effects on both adults and larvae of Tetrapygus niger fed with polluted kelps were determined by assessing growth, fertility, and early larval development. Results revealed that sea urchins fed with polluted kelps from highly impacted zone (HIZ) showed a lower growth (3.

The "Mexican dancer" in Ecuador: molecular confirmation, embryology and planktotrophy in the sea slug .

, otherwise known as the "Mexican dancer", aries in adult size and color across its geographical distribution in Ecuador. Because of morphological variation and the absence of genetic information for this species in Ecuador, we analyzed mtDNA sequences in three populations (Ballenita, La Cabuya, and Mompiche) and confirmed that individuals from the three locations belonged to and that there was no population structure that could explain their morphological differences. Next, we analyzed general aspects about the reproductive biology and embryology of this species.

Short communication: Characterization of the expression of microRNAs in the poecilogonous polychaete B. wellingtonensis.

Poecilogony is a type of reproduction in which a species produces different types of larvae. Boccardia wellingtonensis, is a poecilogonous polychaete with females producing planktotrophic and adelphophagic larvae, in addition to nurse eggs, in the same capsule that differ in feeding behavior. It is still unclear why planktotrophs do not feed on nurse eggs during the intracapsular development and arrest its growth, while adelphophagic larvae consume nurse eggs and planktotrophic larvae inside the capsule, hatching as advance larvae or as juveniles.

Contrasting Metatrochal Behavior of Mollusc and Annelid Larvae and the Regulation of Feeding While Swimming.

Molluscan veliger larvae and some annelid larvae capture particulate food between a preoral prototrochal band of long cilia that create a current for both swimming and feeding and a postoral metatrochal band of shorter cilia that beat toward the prototroch. Larvae encountering satiating or noxious particles must somehow swim without capturing particles or else reject large numbers of captured particles. Because high rates of particle capture are inferred to depend on the beat of both ciliary bands, arrest of the metatroch could be one way to swim while reducing captures.