Introduction

Horsehair worms (Chordodes koreensis) develop as parasites in the bodies of grasshoppers, crickets, cockroaches, and beetles.

Objectives

The aim of this study is to describe the cuticular ultrastructural characteristics of a Chordodes koreensis isolated from canine vomitus.

Methods

The male of Chordodes koreensis in the later larval stage from canine vomitus was investigated by the scanning and transmission electron microscopy.

Results

In cross sections, the body wall is composed of four components, namely epicuticle, cuticle, epidermis, and muscle layers. The epicuticle is a thin superficial layer whose surface shows rows of polygonal elevations called areoles. The epidermis is separated from the muscle layer; the dominant cell type is dense and roughly cuboidal. The muscles were interrupted by the nervous lamella in the only midventral portion. The medulla of muscle plate is composed of lightly stained cytoplasm, mitochondria, weakly developed endoplasmic reticulum, and glycogen granules. Between the medulla of a cell and the plasmalemma lies a broad cortical zone of myofilaments. The characteristic feature of the cytoplasm is that there was no content in peripheral mesenchyme, but there was an abundance of large, clear vacuoles which give the cytosome a foamy appearance. The nucleus of mesenchyme is not easily identified in our specimens.

Conclusions

The internal anatomy of gordiid species is little known. Especially the cuticular structure has major importance for the taxonomy of Nematomorpha. In this report, we described the cuticular ultrastructural characteristics of a Chordodes koreensis.