Taxonomic update and DNA barcoding of Tunisian nasal leeches (Annelida: Hirudiniformes; Praobdellidae): confirming Limnatis nilotica and revealing a second Limnatis species in North Africa.

Leeches of the genus Limnatis are known ectoparasites of vertebrates, including humans and domestic animals, with some species causing significant health complications. In this study, we describe Limnatis anouarensis sp. nov., a new nasal leech species from Tunisia and compare it with Limnatis nilotica sensu stricto from Tunisia and Morocco. Morphological analyses were conducted using light and scanning electron microscopy, focusing on external and internal structures. Additionally, mitochondrial (cytochrome c oxidase subunit I, COI ; 12S rRNA, 12S) and nuclear (28S rRNA, 28S) gene fragments were sequenced for molecular characterisation. The new species is distinguished by its larger size, distinct reproductive system morphology and unique dorsal colouration, characterised by a median orange band and marginal orange stripes, in contrast to the black-striped pattern of L. nilotica (Moore, 1938). Molecular analyses confirmed that mitochondrial markers provide reliable species identification, whereas the analysed fragment of 28S gene was fully conserved and unsuitable for differentiation. These findings confirm the presence of at least two distinct Limnatis species in North Africa, emphasising the need for further taxonomic and ecological studies to clarify their distribution, host specificity and potential medical significance. ZooBank: Integrating DNA barcoding with a comprehensive taxonomic revision, this study confirms the widespread presence of Limnatis nilotica and unveils a second, previously unrecognised species of Limnatis in North Africa. These findings enhance our understanding of the diversity and biogeography of Tunisian nasal leeches, offering significant contributions to regional biodiversity and systematics. (Image credit: Raja Ben Ahmed.) [ABSTRACT FROM AUTHOR]