Integrative species delimitation of Haematobia (Diptera: Muscidae) from Thailand, with the description of Haematobia thailandensis n. sp.

Haematobia Le Peletier & Audinet-Serville (Diptera: Muscidae) is an important genus of blood-feeding muscid flies, which are primarily associated with livestock and wild ungulates, although some species occasionally bite humans. However, taxonomic, molecular, and geometric morphometric (GM) information on Haematobia in Thailand remains limited. This study described a new species of Haematobia from Thailand and evaluated the utility of molecular and wing GM techniques for discriminating among Thai Haematobia species. A new species, Haematobia thailandensis n. sp. was distinguished from its congeners by a combination of diagnostic characters, including a strap-like palpus, a submedian ventral seta on the mid tibia, a short first anal vein ( A 1 + CuA 2 ), and yellow femora. Three Thai Haematobia species ( H. exigua , H. minuta , and H. thailandensis n. sp.) were distinguished from one another using mitochondrial cox 1 and cytb , nuclear ITS2, phylogenetic analysis, molecular species delimitation, and wing GM. Kimura 2-parameter genetic distances, maximum-likelihood phylogenetic trees, and species delimitation analyses confirmed the genetic and phylogenetic separation of the three taxa. Wing GM also demonstrated clear interspecific differentiation, particularly through landmark-based shape analysis, with high classification accuracy. These results demonstrate that molecular and morphometric data provide complementary information for species discrimination among Thai Haematobia . The updated identification key, newly generated DNA sequences, and wing GM data collectively represent valuable reference resources for future studies on Haematobia taxonomy, molecular and morphometric identification, phylogeny, and vector surveillance.