Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)

First Advisor

Joan B. Chapin


The pentatomid genus Thyanta Stal is one of several large genera in the nominate subfamily and tribe. Thyanta belongs among those genera of Pentatomini lacking a spine or tubercle at the base of the third (second visible) abdominal sternite. The genus is divided into two subgenera: Phacidium Breddin, containing a single species, T. aeruginosa Berg; and the nominate subgenus, containing 36 species and one subspecies. The subgenus Thyanta is further divided into four species groups based primarily on differences and similarities in male and female genitalia. The perditor species group contains nine species and one subspecies, the maculata species group consists of 20 species, the juvenca species group includes six species, and the convexa species group contains one species. The genus Thyanta contains one subspecies and 37 species, of which 15 are described here for the first time: T. boliviensis, T. convexa, T. curvata, T. emarginata, T. excavata, T. fimbriata, T. hamulata, T. infuscata, T. obtusa, T. robusta, T. rubicunda, T. sinuata, T. straminea, T. vadosa, and T. xerotica. Additionally, nine new synonymies are recognized: T. casta Stal, 1862, a junior synonym of T. maculata. (F., 1775); T. signoreti Ruckes, 1956, a junior synonym of T. testacea (Dallas, 1951); T. pallidovirens setosa Ruckes, 1957, a junior synonym of T. pallidovirens (Stal, 1859); T. humilis Bergroth, 1891 and T. nitidula Ruckes, 1956, junior synonyms of T. partnuelis (Stal, 1859); T. pallidovirens spinosa Ruckes, 1957, a junior synonym of T. custator accerra McAtee, 1919; T. mendozana Jensen-Haarup, 1928 and T. crinita Ruckes, 1957, junior synonyms of T. acutangula Jensen-Haarup, 1928; and T. humeralis Ruckes, 1956, a junior synonym of T. brasiliensis Jensen-Haarup, 1928.