Skip to main content
ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Mycology and Nematology Genetic Diversity and Biology Laboratory » Research » Publications at this Location » Publication #429327
Research Project: Plant-associated Nematode Management and Systematics and USDA Nematode Collection Curation

Location: Mycology and Nematology Genetic Diversity and Biology Laboratory

Title: Morphological ambiguity between Chambersiella Cobb, 1920 and Geraldius Sanwal, 1971: a taxonomic dilemma solved through a note from N. A. Cobb

Author
item EISENBACK, JONATHAN - Virginia Tech
item Reis Vieira, Paulo

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/2025
Publication Date: 11/4/2025
Citation: Eisenback, J.D., Reis Vieira, P.C. 2025. Morphological ambiguity between Chambersiella Cobb, 1920 and Geraldius Sanwal, 1971: a taxonomic dilemma solved through a note from N.A. Cobb. Journal of Nematology. 57(1): Article e20250051. https://doi.org/10.2478/jofnem-2025-0051.
DOI: https://doi.org/10.2478/jofnem-2025-0051

Interpretive Summary: Free-living nematodes are microscopic worms that play a significant role in the ecology of communities of microorganisms associated with many different kinds of plants, including trees. Accurate identification of these species is therefore crucial for biodiversity assessments, ecological analyses, and assessment of beneficial actitivities. In this study, we examined live and archival specimens from the United States National Nematode Collection (USDANC) to confirm the identification of free-living nematodes that were previously classified as two separate species. This work provides a valuable reference for ecologists and nematologists aiming to accurately identify and quantify these nematodes. This will directly benefit those investigating the pathology of other microorganisms in the soil and their importance in ecological assessments, as well as potential beneficial roles in suppressing pathogenic nematode species.

Technical Abstract: The genera Chambersiella and Geraldius (Nematoda) are nearly morphologically identical, differing primarily in female ovary number: Chambersiella was described as monodelphic, while Geraldius was diagnosed as didelphic. This note reevaluates the validity of that distinction, incorporating original descriptions and a previously overlooked archival note from N. A. Cobb. Field observations failed to recover monodelphic specimens, even in type localities. We propose synonymizing Geraldius with Chambersiella, supported by Cobb’s archived observations and consistent morphological evidence.