"Hyperiid Amphipods (Peracarida) from Banderas Bay, Mexican Tropical Pacific" published on 01 Jan 2008 by Brill.

Porpita porpita is a colonial polymorphic hydrozoan distributed in temperate and tropical zones. This species, like most hydrozoans, possesses a metagenetic life cycle with alternating life forms: medusa stage, polypoid colony, and planula larva. However, a characterization of its early stages of development is still lacking. For this study, an integrative description of the larval stages and the hydroid colony was performed using molecular and histologic tools. The results show that P. porpita develops through three larval stages: preplanula, planula, and premetamorphic planula. The preplanula is distinguished by an absence of polarity, the planula by differentiation of the oral–aboral poles, and the premetamorphic stage by cellular differentiation. Furthermore, two morphologies of young hydroids with different developmental patterns of gonozooids and dactylozooids were observed; notably, it was not possible to observe the gastrozooid in either. Taxonomic identification was confirmed using mitochondrial (COI) and ribosomal (18S and 28S) markers. Our analysis indicates that the COI gene exhibits higher intraspecific variability compared to the 18s and 28s rDNA ribosomal genes. The presented results support the future identification of P. porpita based on morphological characteristics, regardless of the stage of development. Specifically, they shed light on the diversity of mesozooplankton in reef communities.

Chaetognaths are abundant carnivorous zooplankters that play a pivotal role in structuring and regulating the pelagic ecosystem, yet long-term studies of their ecological dynamics in the Mexican Pacific are limited. We investigated the chaetognath community structure in a tropical coastal system of the Mexican Pacific from 2010 to 2016 using monthly zooplankton samples collected across two contrasting hydroclimatic seasons (mixed and stratified) and three interannual ENSO phases: La Niña (Nov 2010–Mar 2012 and Aug–Dec 2016), neutral (Apr 2012–Oct 2014), and El Niño (Nov 2014–May 2016). Our analytical approach integrated: univariate, multivariate, and taxonomic diversity analyses. A total of 145,077 chaetognath specimens were identified from 110 zooplankton samples. Fifteen species were recorded, Zonosagitta bedoti , Parasagitta euneritica , and Flaccisagitta enflata being numerically dominant (73.2% of total abundance) across all seasons and ENSO phases, indicating ecologically resilient local populations. RDA revealed that Z . bedoti and P. euneritica were associated with high 15-CUI values and low temperatures, whereas S. bierii , A. septata , A. regularis , and S. pacifica were linked to moderate-to-high temperatures. Chaetognaths had low mean numerical abundance and diversity during La Niña, high species richness during El Niño 2015–2016, and maximum abundance values during ENSO neutral conditions. These patterns suggest strong local dominance of these predators under anomalously warm conditions.