Fig. 1

Morphological features of Thelazia gulosa (a, b), Thelazia rhodesi (c, d) and Thelazia skrjabini (e, f) males. a Tail of T. gulosa with two spicules (S1, S2), as well as the preanal papillae (Prp). b Proximal part of T. gulosa male, with the buccal capsule (Bc), esophagus (Eso) and nerve ring (NR) highlighted. c Tail of T. rhodesi with measurements of the longer spicule (S1), tail width near the anal pore (TW) and length from the anal pore to the tip of the tail. d Measurements of the parameters located in the proximal end of a T. rhodesi male, anterior width (AntW, halfway between the esophageal-intestinal junction and proximal buccal capsule), width of the esophagus at the junction with the intestine (EsoJ), maximum width of the esophagus (EsoM), anterior width of the esophagus (EsoA, the location of the measurement being the halfway point between the anterior width and the proximal width of the buccal capsule), total striation length (TStL, the distance is divided by the number of striations present) and the anterior nerve ring distance (ANR, the distance between the halfway point of the nerve ring and the proximal end of the esophagus). e Tail end of a T. skrjabini male presenting two spicules (S1, S2) and preanal papillae (Prp). f Proximal end of a T. skrjabini male with the buccal capsule (Bc), esophagus (Eso) and esophageal-intestinal junction (EsoJ) highlighted