L. pagrosomi was found parasitizing the Atlantic horse mackerel (Trachurus trachurus) in the bay of Gemlik, Turkey. The body was between 5036 and 10164 µm long and 478 and 878) µm wide. The proboscis was cylindrical, wider anteriorly, between 2310 and 5313 µm long, and armed with 11 or 12 rows of hooks comprising 11 to 13 hooks in each. The anterior hooks were smaller than the posterior, measuring 34 (24 – 42) µm, 42 (40 – 44) µm, to 61 (54 – 70) µm long. The short proboscis sac consisted of two membranes. The lemnisci were level with the proboscis. One immature male sample had two spherical testes, 216 × 272 µm in diameter. The copulatory bursa was 80 by 140 µm. The cement glands were indistinct. The eggs measured between 70 and 210 µm long and 17 and 52 µm wide.[2]
P. laevis is a parasitic acanthocephalan worm that can influence the reaction of its intermediate host, the freshwater amphipod Gammarus pulex, to the smell of potential predators like perch, Perca fluviatilis.[3][4]
P. laevis facilitates its movement from its initial host. Research has demonstrated that organisms affected by the parasite exhibit a diminished or inverted avoidance response to the scent of predators when compared to uninfested specimens, supporting the notion that the parasite manipulates its host, with the goal of passing itself on to its definitive host, a freshwater fish. Affected specimens also demonstrate vibrant changes in color, making them more visible to predators.[5][6]
This worm swells its proboscis to press microneedles into the intestinal wall, with a very strong adhesive force. This has inspired a structural skin graft adhesive that sticks strongly but has minimal tissue damage while in place and upon removal.[7]