Longidorus ferrisi n. sp. from California Citrus

Area of Science:

• Nematology
• Plant-parasitic nematodes
• Taxonomy

Background:

• Longidorus species are important plant-parasitic nematodes affecting agriculture.
• Accurate identification and differentiation of species are crucial for effective management strategies.
• Previous taxonomic work has established several Longidorus species with varying host ranges and geographic distributions.

Purpose of the Study:

• To describe and formally name a new species of Longidorus discovered in Napa County, California.
• To differentiate the new species from closely related and morphologically similar Longidorus species using detailed morphological and molecular data.
• To contribute to the understanding of nematode biodiversity and taxonomy within the Longidoridae family.

Main Methods:

• Specimens were collected from the roots of a citrus tree.
• Morphological characterization included measurements of various body parts, ratios (a, c, c´), head and guide ring position, odontostyle length, lip region width, mid-body width, and spicule length.
• Molecular analysis involved sequencing the nuclear 18S ribosomal DNA (18S rDNA) gene to assess phylogenetic relationships.

Main Results:

• A new species, Longidorus ferrisi n. sp., is described.
• Longidorus ferrisi n. sp. is distinguished from Longidorus elongatus by a greater c-ratio, lesser c´ value, more posterior guide ring, presence of sperm in mature females, and a 1:1 female to male ratio.
• Distinct morphological differences were observed when comparing Longidorus ferrisi n. sp. to L. artemisiae, L. crassus, L. glycines, and L. milanis, including body length, ratios, and specific anatomical features. The 18S rDNA sequence analysis confirmed its uniqueness among sequenced Longidorus species.

Conclusions:

• Longidorus ferrisi n. sp. represents a distinct new species within the Longidorus genus.
• The combination of morphological and molecular data provides a robust basis for its taxonomic description and differentiation.
• This finding expands the known diversity of Longidorus nematodes and highlights the importance of continued surveys for identifying new species.