Contracaecum fioravantii n. sp. from the black-crowned night heron (Nycticorax nycticorax)
- 1Department Veterinary Medical Sciences, University of Bologna, Ozzano Emilia, Italy
- 2Pathology and Diagnostics Division, Kimron Veterinary Institute, Israel
- 3Department of Biology, University of Puerto Rico, Puerto Rico
Abstract
The genus Contracaecum comprises anisakid nematodes with complex life cycles involving aquatic intermediate hosts and piscivorous birds as definitive hosts. The black-crowned night heron (Nycticorax nycticorax) is a widespread ardeid species known to host diverse helminth communities, including Contracaecum spp., although species-level identification is often lacking. In this study, we describe a new species, Contracaecum fioravantii n. sp., based on an integrative morphological and molecular approach. Adult nematodes were collected from 3 N. nycticorax individuals in Israel and examined using light and scanning electron microscopy. The new species is characterized by a distinct combination of morphological features, including robust, subequal spicules, a sagittate tail tip in males, and a specific arrangement of caudal papillae and phasmids, distinguishing it from closely related taxa such as C. microcephalum and members of the C. rudolphii complex. Multivariate morphometric analyses supported its separation from congeners. Molecular characterization based on ITS (Internal Transcribed Spacers) rDNA and cox2 mtDNA sequences revealed high similarity with previously unidentified Contracaecum spp. from ardeid hosts in China, and phylogenetic analyses placed the new species in a well-supported, distinct clade. These findings highlight the hidden diversity within Contracaecum and underscore the importance of combining morphological and molecular data for accurate species delimitation. The identification of C. fioravantii n. sp. contributes to a better understanding of host–parasite relationships in piscivorous birds and suggests a wider geographic distribution linked to migratory pathways of N. nycticorax.
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BibTeX
@article{tedesco2026contracaecum,
title = {{Contracaecum fioravantii n. sp. from the black-crowned night heron (Nycticorax nycticorax)}},
author = {Perla Tedesco and Nadav Davidovich and Sean A. Locke and Andrea Gustinelli and Monica Caffara},
journal = {Parasitology},
year = {2026},
month = jul,
doi = {10.1017/s0031182026102558},
url = {https://doi.org/10.1017/s0031182026102558},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Contracaecum fioravantii n. sp. from the black-crowned night heron (Nycticorax nycticorax)
AU - Perla Tedesco
AU - Nadav Davidovich
AU - Sean A. Locke
AU - Andrea Gustinelli
AU - Monica Caffara
PY - 2026
DA - 2026/07/27
JO - Parasitology
DO - 10.1017/s0031182026102558
UR - https://doi.org/10.1017/s0031182026102558
AB - The genus Contracaecum comprises anisakid nematodes with complex life cycles involving aquatic intermediate hosts and piscivorous birds as definitive hosts. The black-crowned night heron (Nycticorax nycticorax) is a widespread ardeid species known to host diverse helminth communities, including Contracaecum spp., although species-level identification is often lacking. In this study, we describe a new species, Contracaecum fioravantii n. sp., based on an integrative morphological and molecular approach. Adult nematodes were collected from 3 N. nycticorax individuals in Israel and examined using light and scanning electron microscopy. The new species is characterized by a distinct combination of morphological features, including robust, subequal spicules, a sagittate tail tip in males, and a specific arrangement of caudal papillae and phasmids, distinguishing it from closely related taxa such as C. microcephalum and members of the C. rudolphii complex. Multivariate morphometric analyses supported its separation from congeners. Molecular characterization based on ITS (Internal Transcribed Spacers) rDNA and cox2 mtDNA sequences revealed high similarity with previously unidentified Contracaecum spp. from ardeid hosts in China, and phylogenetic analyses placed the new species in a well-supported, distinct clade. These findings highlight the hidden diversity within Contracaecum and underscore the importance of combining morphological and molecular data for accurate species delimitation. The identification of C. fioravantii n. sp. contributes to a better understanding of host–parasite relationships in piscivorous birds and suggests a wider geographic distribution linked to migratory pathways of N. nycticorax.
SN - 0031-1820
SN - 1469-8161
ER -