Spirocamallanus timmi is a yellowish worm with a thick, striated cuticle. Males are smaller than females, with males being shorter and of a uniform width, while females are longer and have a slightly variable width. The buccal capsule is continuous and barrel-shaped, featuring two sets of spiral thickenings and a basal portion with two knob-like structures. The buccal capsule is larger in females. The oesophagus consists of a muscular part, which is longer in males than in females, and a posterior glandular part, which is also longer in males. Tridents are absent. Males have two unequal spicules: the right spicule is elongated, while the left spicule is shorter with a hook-like tip. There are twelve pairs of pedunculated caudal papillae in males, with six pairs preanal and six pairs postanal, arranged in two groups. The male tail is ventrally coiled. In females, distinct cervical papillae are present. The vulva, located a considerable distance from the anterior end, has two lips. The uterus contains numerous embryos. The female tail is short, with cuticular spines projecting from the posterior end.