Aspectos genéticos e morfológicos de pueruli de lagostas do gênero Panulirus na orla de Fortaleza

Abstract

In recent decades, the state of Ceará has been the largest lobster exporter in Brazil, with emphasis on lobsters from genus Panulirus. The main species exploited by the fishing sector are those found in higher abundance, Panulirus argus and Panulirus laevicauda. Despite decades of scientific studies and fishery management, fundamental aspects of the biology of these lobsters have yet to be elucidated. One of the most significant gaps in knowledge is about recruitment. In the recruitment process, one of the crucial phases is settlement, represented in the life cycle by the puerulus phase. Studies on the distribution and abundance of lobster pueruli are scarce and become more complex due to the difficulty in identifying the species at this stage of development. This study study aimed to present morphological descriptions of the different stages of development of pueruli sampled on the coast of Ceará, in order to allow identification at the lowest possible taxonomic level. Today, the morphological identification of species is often supported by genetic characterizations. In order to establish a framework for this type of complementary study, in addition to the morphological description, the mitochondrial genome of Panulirus lobsters was also reviewed and analysed. Morphological analyses were performed through observations and measurements under a stereomicroscope and digital photo documentation. Genetic analyses were based on complete mitochondrial genomes available on GenBank, as well as on unpublished 16S gene partial sequences for Panulirus echinatus, which were used to build phylogenetic trees. The morphological analyses performed revealed a similar pattern of structures and coloration among samples that were at the same stage of development. It was possible to classify the later stage samples at species level, but the earlier stages showed characteristics that will need genetic validation. The genetic analysis revealed stability in the mitochondrial genome among the different Panulirus species, when compared to the genome of Drosophila melanogaster. The most conserved gene was cox1 (p = 0,189) and the most variable portion of the genome was the control region (p= 0, 390). Assessed separately, all genes produced trees of similar topology with the exception of the control region. The phylogenetic trees divided the species into two groups, consistent with current knowledge about the evolution of these lobsters. The 16S gene from P. echinatus showed low intraspecific variability and was consistently different from the other species, indicating that it could be used for genetic characterization of pueruli.