Cuticle with 4 incisures occupying 1/4 body width. Lip region set off by expansion. Spear 11u-13u long with small knobs. Corpus of esophagus extending half length of spear. Esophageal lobe slender, extending back 3 or 4 body widths. Excretory pore opposite nerve ring. Hemizonid about 1 body width posterior to pore. Intestinal cells each with 2 small, closely approximated nuclei. Vulva with elevated labia. Vagina curved in and forward halfway across body. Uterus at first an open chamber in which sperms usually are present, then a strong valvular apparatus leading to an elongate spermatheca with sperms arranged in orderly rows along its walls. Ovary extending forward to esophageal region, then reflexed back 5 to 8 body widths. Oocytes arranged in single file except for short region of multiplication. An egg was 20u x 60u. Posterior uterine branch expanded into an elongate sperm storage chamber reaching halfway to rectum. Posterior cells of intestine clear. Phasmids on subventral side of terminus which bears a hyaline mucro. Male more slender than female with outstretched testis. Sperms 5u long and 3 or 4u wide. Spicula conspicuous because of their hooked termini, hence the specific name hamatus.
Aphelenchoides hamatus is immediately distinguished by the hamate spicula, set off lip region, slightly knobbed spear, long reflex in ovary and hyaline posterior cells of intestine.
Holotype female, allotype male and other specimens as indexed under Aphelenchoides 5.
Habitat: About iris roots, Horticultural Gardens, South Dakota State University, Brookings.