Both sexes fully winged. Body dark brown, abdominal tergites III–VIII anterolaterally with chalky-white areas; antennal segments III–V yellow at base; tarsi, also base and apex of mid and hind tibiae yellow; fore wing pale, sometimes with dark line medially on basal half. Head longer than wide; cheeks with prominent bristle-bearing warts; eyes large; maxillary stylets long and close together medially; postocular setae capitate but small, posterior to inner margin of eyes; mouth cone extending across prosternum. Antennae 8-segmented; segments III–VI constricted to apical neck; III–IV with 3 stout sensoria. Pronotum reticulate, 5 pairs of capitate major setae present; basantra absent. Fore tarsus with prominent tooth; fore femora with sub-apical tubercle on inner margin. Fore wings parallel sided. Pelta reticulate; tergite IX setae blunt at apex.
Male sternite VIII with median transverse pore plate.
The genus Acanthothrips includes 13 species, of which one is Holarctic, one is from northern Europe, five are known only from North America, and six are from the Neotropics including Mexico. Priesner (1964) distinguished this genus from the wordwide genus Hoplandrothrips on the basis that the fore wings are parallel sided. Although this is true of A. nodicornis, the fore wings of A. albivittatus and A. argentifer are constricted medially at least as much as in some species of Hoplandrothrips. The antennae of A. albivittatus are uniformly dark, whereas the median antennal segments are largely yellow in the other two species recorded from California. Specimens of A. argentifer Cott have not been studied, but that species was described as being reticulate like A. nodicornis, but the females were "without a distinct tarsal tooth".
Acanthothrips nodicornis (Reuter)
Breeding on dead branches
Unidentified fungal hyphae on dead branches
Widespread across northern parts of northern hemisphere