Abstract Marine turtle hybridization is usually sporadic and involves reports of only a few individuals; however, Brazilian populations have high hybridization rates. Here we investigated the presence of hybrids in morphologically identified immature hawksbills (Eretmochelys imbricata) along the South Western Atlantic (SWA). We sequenced one mitochondrial (D-Loop) and three nuclear DNA (RAG1, RAG2, and CMOS) markers to better understand the patterns and characteristics of hybrids. We identified 22 hybrids (n = 270), 11 of them at the extreme South of the SWA. Uruguay had the highest hybrid frequency in the SWA (~37.5%) followed by southern Brazil with 30%. These are common areas for loggerheads (Caretta caretta) but uncommon for hawksbills, and these hybrids may be adopting the behavior of loggerheads. By analyzing nuclear markers, we can infer that 50% of the sampled hybrids are first generation (F1) and 36% are the result of backcrosses between hybrids and pure E. imbricata (> F1). We also report for the first time immature E. imbricata x Lepidochelys olivacea hybrids at the Brazilian coast. Considering the high frequency of hybrids in the SWA, continuous monitoring should be performed to assess the fitness, genetic integrity, and extent of changes in the gene pools of involved populations.

ABSTRACT Crane flies are the most diverse group within Diptera, but they are rarely studied in coastal ecosystems. Considering the scarcity of information on the biology and ecology of this group in the Neotropics, and the sparse literature available for taxonomic identification, we developed a descriptive checklist that incorporates morphology and DNA barcoding. We also created a generic identification key for crane flies of southern Brazilian salt marshes. We sampled crane flies continuously at three areas along the Patos Lagoon salt marshes over one year. A total of 14 genera/subgenera, 6 species, and 12 morphotypes belonging to Limoniidae and Tipulidae were identified. Distribution ranges of Symplecta cana (Walker, 1848) and two Ormosia Rondani, 1856 species were expanded. mtDNA COI sequences were compared to the BOLD and NCBI databases, but were matched only at the family level. Therefore, we provided sequences to both platforms, updated to the genus level. We found low (0.00-0.03) intraspecific and high (0.11-0.25) interspecific molecular differences indicating that the mtDNA COI region is adequate for distinguishing species within the Tipuloidea. The Dicranomyia Stephens, 1829 species complex showed low genetic difference, indicating that they could be one species with high morphological plasticity. This study will serve as a basis for future research on insects of Neotropical salt marshes.

We analyzed mtDNA control region sequences of green turtles (Chelonia mydas) from Arvoredo Island, a foraging ground in southern Brazil, and identified eight haplotypes. Of these, CM-A8 (64%) and CM-A5 (22%) were dominant, the remainder presenting low frequencies (< 5%). Haplotype (h) and nucleotide ( π) diversities were 0.5570 ± 0.0697 and 0.0021 ± 0.0016, respectively. Exact tests of differentiation and AMOVA ΦST pairwise values between the study area and eight other Atlantic foraging grounds revealed significant differences in most areas, except Ubatuba and Rocas/Noronha, in Brazil (p > 0.05). Mixed Stock Analysis, incorporating eleven Atlantic and one Mediterranean rookery as possible sources of individuals, indicated Ascension and Aves islands as the main contributing stocks to the Arvoredo aggregation (68.01% and 22.96%, respectively). These results demonstrate the extensive relationships between Arvoredo Island and other Atlantic foraging and breeding areas. Such an understanding provides a framework for establishing adequate management and conservation strategies for this endangered species.