Dr. Viktoria Esther Bogantes Aguilar

A complete picture of diet composition is an essential element to understanding the ecological role of organisms. Moreover, diet studies can serve as an important tool for monitoring species and changes to the food web. One method to provide resolution when studying the diet of avian species is DNA metabarcoding of fecal samples. As such, we used DNA analysis to determine the diet of the Least Tern Sternula antillarum and compare results with diet analysis based on composition of fish dropped within breeding colonies. Comparisons between adult and chick fecal samples were also made across three years and within three zones of sample collection. Results show differences in diet composition between the two methods as well as across zones and years. Significant differences between prey items of adults and chicks were also identified. Metabarcoding data indicate that Least Terns are consuming Lionfish Pterois spp. (most likely in larval stages), a prey item that had not been previously recorded for Least Terns, and that data obtained from dropped fish might not be representative of chick diet. Differences across years and zones are likely due to shifts in the abundance and availability of prey items.

Most efforts at improving accuracy in phylogenomic reconstructions have focused on improving tree-building methods or orthology determination. Even though the use of whole genome sequence or transcriptome data is increasing, the degree to which accurate genome assembly and annotation influence phylogenetic inference has not been well explored. Here, we use low-coverage whole genome sequencing of spionid annelids to explore the impact of different assemblers and annotation strategies on tree reconstruction. We also produce a phylogenetic hypothesis that spans the breadth of Spionidae, examining the current systematics of the group, which is based on morphological parsimony analyses and classical taxonomy. Our results show that both assembly and annotation can have important consequences for the pool of loci that may be available for tree reconstruction. When an identical phylogenomic pipeline is used, differences in assembly and annotation can account for variation in reconstructed topologies. Interestingly, the completeness and depth of the data used for training annotation software (i.e. data from model systems) appear to be more important, by some measures, than the degree of phylogenetic relatedness of the organism from which training data are drawn. Despite variation in recovered topologies, the recognised subfamily Spioninae is nested within Nerininae, suggesting that diagnostic characters of Nerininae (e.g. thick egg membrane, short-headed sperm) are symplesiomorphies of Spionidae rather than apomorphies of a particular subclade. With the increased use of genomic data, our results advocate for a broader consideration of how assembly and annotation may impact data matrices used in phylogenomic analyses.

In this study, we describe the complete mitochondrial genome of Diopatra cuprea (Bosc, 1802). The mitogenome was found to contain 14,990 base pairs (67.53% A + T content), with a total of 37 genes (13 protein coding, 22 transfer RNAs, and 2 ribosomal RNAs). This study also examined mitogenome phylogenetics relationships of closely related species and recovered that D. cuprea is closely related to eunicids. This work has added to the genetic resources for furthering evolutionary studies of Annelida.

The marine feather duster, Bispira melanostigma (Schmarda, 1861), is a tube-dwelling annelid that contributes to ecological and biogeochemical processes in benthic communities. Due to the lack of scientific data, B. melanostigma is often difficult to distinguish from other species of marine worms through morphological characteristics alone. In this study, we report the complete mitochondrial genome of Bispira melanostigma. The complete mitogenome contained 20,624 bp length with a total of 13 protein-encoding genes, 21 tRNA, and 2 rRNA genes. Phylogenetic analysis of the complete mitochondrial DNA of B.melanostigma can aid in the understanding of evolutionary relationships within Sabellidae.

The Loggerhead sponge (Spheciospongia vesparium) is an ecologically important marine species of sponge that provides habitat and food sources to biodiversity hotspots in the Caribbean Sea and along the coasts of Florida. In this study, the complete mitochondrial genome of the sponge, S. vesparium was sequenced and reported. The mitochondrial genome of S. vesparium was 21,763 base pairs, and consisted of 14 protein-coding genes, 26 tRNA genes, and two rRNA genes. The total nucleotide content comprised 31.01% A, 36.04% T, 11.08% C, and 21.88% G, with a lower GC content of 32.95%. This study provides a phylogenetic analysis of S. vesparium and relative sponges in Demospongiae.

Thyonella gemmata , also known as the Green sea cucumber, is a biomedically and ecologically important species. In this study, the complete mitogenome of T. gemmata (Echinodermata: Holothuroidea) collected from the Florida Panhandle, USA is reported. The mitochondrial genome of T. gemmata consisted of 15,696 base pairs, and was composed of 36.10% A, 28.27% T, 23.18% C, and 12.45% G. There were 13 protein coding genes, 22 tRNA genes, and 2 rRNA genes within the mitogenome of T. gemmata. Mapping out the complete mitochondrial genome of T. gemmata, will help aid in future evolutionary studies and can be applied to future phylogenetic research of holothurians and related species.

In this study, the complete 16,979 bp mitochondrial genome of Lysmata wurdemanni (Gibbes, 1850) was determined from a specimen collected from Apalachee Bay, U.S. The mitogenome contains 37 genes, and consists of 32.33% A, 35.01% T, 19.55% C, and 13.10% G, with a total G + C content of 32.65%. A maximum likelihood phylogenetic tree based on mitochondrial protein-coding genes suggested L. wurdemanni is clustered with Lysmata vittata and Lysmata amboinensis, based on available mitochondrial sequences of relatives. These data are useful in determining phylogenetic relationships between Lysmatidae and Thoridae. The sequenced mitochondrial genome may also assist in understanding evolutionary distinctions and breeding strategies in hermaphroditic species.