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| Author(s): |
Caio dos Santos Nogueira
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Botucatu. 2023-05-18. |
| Institution: | Universidade Estadual Paulista (Unesp). Instituto de Biociências. Botucatu |
| Defense date: | 2023-05-05 |
| Advisor: | Rogerio Caetano da Costa; João Alberto Farinelli Pantaleão |
| Abstract | |
Macrobrachium amazonicum and M. pantanalense are two closely related freshwater prawn species occurring in Brazil. Macrobrachium pantanalense is an endemic species found in the Pantanal regions and was previously considered a clade within the M. amazonicum complex. The classification of this lineage as a distinct species has been controversial due to its high morphological similarity with M. amazonicum and the low genetic distance between the species. Thus, the aim of this study was to evaluate whether commonly used tools in integrative taxonomy support the existence of M. pantanalense. Four different approaches were employed, including hybridization experiments, geometric morphometrics, description of the male reproductive system morphology (MRS) and sperm ultrastructure, and larval morphology and morphometrics. Interespecific differences were observed across all of these integrative approaches. The hybridization experiments revealed reproductive isolation between these organisms, indicating that these species do not naturally interbreed. Geometric morphometrics highlighted differences in the shape of five taxonomically relevant structures. While no differences were observed in MRS morphology, histochemical variations were found in the secretions composing the spermatophore. Spermatozoa exhibited variations in shape between the two species. Larvae displayed heterochronic and morphometric variations throughout their development. These integrative analyses demonstrate that biological traits of M. amazonicum and M. pantanalense exhibit variations, supporting the separation of both lineages. Some of these differences are subtle, possibly due to the recent speciation process between these groups. (AU) | |
| FAPESP's process: | 19/00661-3 - A comparative interdisciplinary analysis between the prawns Macrobrachium amazonicum (Heller, 1862) and Macrobrachium pantanalense (dos Santos, Hayd & anger, 2013) support the interspecific differentiation? |
| Grantee: | Caio dos Santos Nogueira |
| Support Opportunities: | Scholarships in Brazil - Doctorate |