Actumnus ngankeeae sp. nov. and Pilumnus swajayai Ng & Rahayu, 2021, pilumnid crabs from Japan (Crustacea: Decapoda: Brachyura)
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Summary
This summary is machine-generated.Two new rare crab species, Actumnus ngankeeae and Pilumnus swajayai, were discovered in Japan. This finding expands the known diversity of the Pilumnidae family in the region.
Area Of Science
- Marine Biology
- Crustacean Taxonomy
- Zoology
Background
- The family Pilumnidae comprises numerous crab species, with ongoing discoveries contributing to our understanding of marine biodiversity.
- Accurate identification and description of new species are crucial for ecological and evolutionary studies.
Purpose Of The Study
- To describe two new and rare crab species belonging to the family Pilumnidae, Actumnus ngankeeae sp. nov. and Pilumnus swajayai.
- To document the occurrence of these species in Japanese waters, specifically the Ogasawara (Bonin) Islands and Ryukyu Islands.
Main Methods
- Morphological examination of crab specimens, focusing on carapace shape, granulation, setation, and limb armature.
- Comparative analysis with related species and genera to confirm taxonomic placement.
- Geographical distribution recording.
Main Results
- Actumnus ngankeeae sp. nov. is described from the Ogasawara Islands, characterized by a convex, granulate carapace and stout chelipeds.
- Pilumnus swajayai is reported from the Ryukyu Islands, distinguished by its tomentose covering, specific carapace armature, and spinulated ambulatory legs.
- The record of Pilumnus swajayai in Japan represents its second known occurrence globally.
Conclusions
- The discovery and description of Actumnus ngankeeae and Pilumnus swajayai enhance the known crab diversity in Japan.
- These findings contribute to the taxonomic and biogeographic understanding of the Pilumnidae family in the Indo-Pacific region.

