Ultrastructure and elemental depositions of hooks in Centrorhynchus cf. aluconi (Acanthocephala: Polymorphida)

Abstract

Centrorhynchus are an acanthocephalan parasite, also known as a thorny-headed worm, which infects many avian and reptile species. They are dominated by hook-rows on their proboscis. However, microstructures and elemental profiles of the hooks are unclear for this worm. The aims of this study were to report the ultrastructure and elemental deposition of hooks in C. cf. aluconi collected from Chinese ratsnakes by using FESEM-EDX and TEM. Hook surfaces show narrow folds alternating with grooves longitudinally. However, surfaces of proboscis were quite smooth. Ultrastructure of the hook layers consisted of the first and second outer hook layers, and the first, second, and third inner layers. Hook surfaces are composed of sulfur (15.88 ± 3.01 of weight %), calcium (6.03 ± 3.83), phosphorus (13.73 ± 2.89), and others. Inside hooks consist of sulfur (24.81 ± 4.36), calcium (7.16 ± 1.59), phosphorus (11.86 ± 5.20), and others. Sulfur was predominant on the hook surface and the outer hook layer but not in the inner layer. Calcium had a high composition in the inner layer. These results may offer important data for the identification of C. aluconi and the understanding of the ultra-architecture and mineral profiles of hooks in this species.

Keywords

• c. cf. aluconi
• thorny-headed worms
• ultrastructure
• elements