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Célio Magalhães

A new genus and species of pseudothelphusid crab of the tribe Kingsleyini Ortmann, 1897, from the Tapajós River, a southern tributary of the Amazon River basin in the state of Pará, Brazil, is described and illustrated. Michaelthelphusa tuerkayi gen. et sp. nov. is characterized by the male first gonopod possessing marginal and lateral sutures fused at the distal third of the stem and the merged portion strongly twisted towards the lateral side; an apex transversally expanded along caudal-cephalic axis, with a well-developed, but low, somewhat depressed, apical plate; apical plate with spine-like outgrowth cross overlapping the spine-like projection of the mesial process. Moreover, the relationship of the new genus and species with other pseudothelphusid genera from the Amazon basin is discussed.

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Célio Magalhães

Abstract

A new genus and species of pseudothelphusid crab of the tribe Kingsleyini Ortmann, 1897, from the Tapajós River, a southern tributary of the Amazon River basin in the state of Pará, Brazil, is described and illustrated. Michaelthelphusa tuerkayi gen. et sp. nov. is characterized by the male first gonopod possessing marginal and lateral sutures fused at the distal third of the stem and the merged portion strongly twisted towards the lateral side; an apex transversally expanded along caudal-cephalic axis, with a well-developed, but low, somewhat depressed, apical plate; apical plate with spine-like outgrowth cross overlapping the spine-like projection of the mesial process. Moreover, the relationship of the new genus and species with other pseudothelphusid genera from the Amazon basin is discussed.

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Célio Magalhães, Vitor Q. A. Sanches, Leonardo G. Pileggi and Fernando L. Mantelatto

Abstract

A new species of freshwater crab of the genus Fredius Pretzmann, 1967, from the state of Rondônia, Brazil, is described, illustrated, and characterized in terms of an mtDNA sequence (16S rRNA). Fredius buritizatilis sp. nov. is distinguished from its congeners by the following characters of the male first gonopod: a mesial lobe comprising a long, narrow, spear-like projection that is recurved upward; a cephalic lobe with a distinctly inflated proximal portion with a large patch of strong, corneous spines along its mesial and caudal surfaces; and an auxiliary lobe on the caudal surface that is inflated and shorter than cephalic lobe. The mt16S rRNA sequence of Fredius buritizatilis sp. nov. establishes its systematic position in relation to other species of Fredius included in the analysis. The occurrence of several species of Pseudothelphusidae in the state of Rondônia, Brazil, as well as the relationships of Fredius buritizatilis sp. nov. to other species of the genus, suggests that the affinities of some Brazilian pseudothelphusids are not as close as their geographical proximity might suggest.

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Sebastian Klaus, Célio Magalhães, Rodolfo Salas-Gismondi, Martin Gross and Pierre-Olivier Antoine

We describe claw fragments of fossil primary freshwater crabs from three areas in the Amazon basin, Tarapoto (Early Oligocene) and Contamana (Middle Eocene to early Late Miocene) in Peru, and Eirunepé (Late Miocene) in Brazil. All these fragments most likely belong to the family Trichodactylidae. We show a continuous presence of primary freshwater crabs in proto-Amazonian lowlands from the Middle Eocene to the Late Miocene and can thus shift the earliest appearance date of freshwater-adapted brachyurans into the Eocene, at least in the Neotropics.

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Sebastian Klaus, Célio Magalhães, Rodolfo Salas-Gismondi, Martin Gross and Pierre-Olivier Antoine

Abstract

We describe claw fragments of fossil primary freshwater crabs from three areas in the Amazon basin, Tarapoto (Early Oligocene) and Contamana (Middle Eocene to early Late Miocene) in Peru, and Eirunepé (Late Miocene) in Brazil. All these fragments most likely belong to the family Trichodactylidae. We show a continuous presence of primary freshwater crabs in proto-Amazonian lowlands from the Middle Eocene to the Late Miocene and can thus shift the earliest appearance date of freshwater-adapted brachyurans into the Eocene, at least in the Neotropics.

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Célio Magalhães, Carola Becker, Peter Davie, Sven Klimpel, Pedro Martínez-Arbizu and Moritz Sonnewald