New data on eggshell structure of capillariid species: a SEM perspective

Area of Science:

• Veterinary parasitology
• Nematology
• Scanning Electron Microscopy

Background:

• Capillariidae nematodes exhibit complex taxonomy, with eggshell structure crucial for identification.
• Light microscopy (LM) presents challenges in visualizing diverse capillariid eggshell ornamentation.
• Existing LM-based eggshell categories (smooth, punctuated, reticulated I/II) require further validation.

Purpose of the Study:

• To characterize Capillariidae eggshell structures using scanning electron microscopy (SEM).
• To compare SEM observations with existing LM-based eggshell ornamentation categories.
• To evaluate the taxonomic utility of SEM-derived eggshell features for Capillariidae species identification.

Main Methods:

• SEM imaging of Capillariidae eggs from 12 species across 5 genera (Aonchotheca, Baruscapillaria, Capillaria, Echinocoleus, Eucoleus).
• Eggs were sourced from a curated helminthological collection with species-level identification.
• Comparative analysis of SEM images against corresponding LM images and established ornamentation categories.

Main Results:

• SEM provided high-resolution visualization of capillariid eggshell surface topography.
• Observed SEM eggshell patterns were correlated with LM-based ornamentation categories.
• The study identified previously undocumented SEM eggshell details for curated Capillariidae species.

Conclusions:

• Capillariid eggshell ornamentation categories derived from LM do not consistently align with genera or infection sites.
• SEM reveals specific, supplementary taxonomic features at the species level within Capillariidae.
• This research enhances the understanding of Capillariidae eggshell morphology and its taxonomic significance.