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1. Introduction The order Decapoda constitutes a large representative group in the extensive and specious subphylum Crustacea. Chace (1951), Martin and Davis (2001), De Grave et al. (2009), and De [...], Genome size (GS) or DNA nuclear content is considered a useful index for making inferences about evolutionary models and life history in animals, including taxonomic, biogeographical, and ecological scenarios. However, patterns of GS variation and their causes in crustaceans are still poorly understood. This study aimed to describe the GS of five Neotropical Synalpheus non-gambarelloides shrimps (S. apioceros, S. minus, S. brevicarpus, S. fritzmueller, and S. scaphoceris) and compare the C-values of all Caridea infraorder in terms of geography and phylogenetics. All animals were sampled in the coast of Sao Paulo State, Brazil, and GS was assessed by flow cytometry analysis (FCA). The C-values ranged from 7.89 pg in S. apioceros to 12.24 pg in S. scaphoceris. Caridean shrimps had higher GS than other Decapoda crustaceans. The results reveal a tendency of obtaining larger genomes in species with direct development in Synalpheus shrimps. In addition, a tendency of positive biogeographical (latitudinal) correlation with Caridea infraorder was also observed. This study provides remarkable and new protocol for FCA (using gating strategy for the analysis), which led to the discovery of new information regarding GS of caridean shrimps, especially for Neotropical Synalpheus, which represents the second-largest group in the Caridea infraorder. Key words: C-value, snapping shrimp, Decapoda, DNA content La taille du genome ou le contenu en ADN nucleaire est considere comme un indice utile pour faire des inferences au sujet des modeles evolutifs et de l'histoire de vie chez les animaux, incluant des scenarios taxonomiques, biogeographiques et ecologiques. Cependant, les types de variation quant a la taille des genomes ainsi que leurs causes sont encore mal compris chez les crustacees. Cette etude visait a decrire la variation pour la taille du genome chez cinq especes de crevettes neotropicales Synalpheus nongambarelloides (S. apioceros, S. minus, S. brevicarpus, S. fritzmueller et S. scaphoceris) et de comparer les valeurs C au sein du sous-ordre Caridea en termes de geographie et de phyllogenetique. Tous les specimens ont ete captures sur la cote de l'etat de Sao Paulo au Bresil et la taille du genome a ete mesuree par cytometrie en flux (FCA). Les valeurs C variaient entre 7,89 pg chez le S. apioceros et 12,24 pg chez le S. scaphoceris. Les crevettes carideennes presentaient des genomes de plus grande taille que les autres crustacees de l'ordre des Decapoda. Les resultats ont revele une tendance a l'accroissement de la taille des genomes chez les crevettes du genre Synalpheus presentant un developpement direct. De plus, les auteurs ont egalement note une correlation biogeographique positive (latitudinale) au sein du sous-ordre Caridea. Cette etude rapporte un nouveau protocole remarquable pour l'analyse FCA (faisant appel a une strategie d'analyse hierarchique), lequel a permis de faire des observations inedites au sujet de la taille du genome chez les crevettes carideennes, specifiquement chez des especes neotropicales du genre Synalpheus, lequel represente le second plus grand groupe au sein du sous-ordre Caridea. [Traduit par la Redaction] Mots-cles : valeur C, crevettes pistolet, Decapoda, contenu en ADN

Species of the Rhodnius genus have a complex taxonomy because the events of phenotypic plasticity and cryptic speciation make it difficult to correctly classify these vectors. During the taxonomic history of the genus, five synonymization events occurred. Additionally, some authors suggest that R. milesi possibly represent only phenotypic polymorphisms of R. neglectus. Thus, we analyzed the specific status of R. milesi in relation to R. neglectus using phylogenetic studies with the mitochondrial gene cytochrome B and the study of reproductive barriers. The phylogenetic reconstruction grouped R. milesi together with R. neglectus from different localities, demonstrating that these taxa represent the same species based on the phylogenetic species concept. Experimental crosses demonstrate the absence of pre- and postzygotic barriers under laboratory conditions. Additionally, when the hatch rates of crosses are compared to intraspecific crosses, it can be noted that they are high and very similar. Finally, the mortality rate of the hybrids does not indicate hybrid inviability, the absence of chromosome pairing errors does not indicate hybrid sterility, and the proportion between male and female hybrids demonstrates that Haldane's rule was not acting. Therefore, we perform the formal synonymization of R. milesi with R. neglectus. [ABSTRACT FROM AUTHOR]