Tychius semisquamosus
J. Faust, 1893
Tychius semisquamosus is a of leguminous seed weevil in the Curculionidae, described by Faust in 1893. It belongs to the semisquamosus group of North American Tychius species, which are associated with plants in the Astragalus and Lotus. The species has been subject to taxonomic revision, with several previously described species (T. lamellosus, T. squamosus, T. intermixtus) now synonymized under this name. It represents part of a North American fauna derived from multiple independent dispersals from Eurasia.
Pronunciation
How to pronounce Tychius semisquamosus: /ˈtaɪ.ki.us ˌsɛ.mɪ.skweɪˈmoʊ.səs/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
Members of the semisquamosus group can be distinguished from other North American Tychius by associations with Astragalus in American groups and with Lotus. T. semisquamosus specifically may be distinguished from T. tectus and T. liljebladi, which are more closely allied to Eurasian relatives and have hosts in Oxytropis and Eurasian groups of Astragalus.
Distribution
North America. The semisquamosus group appears to have been established in North America prior to the arrival of T. liljebladi and T. tectus.
Diet
Feeding habits involve leguminous seeds; plants include of Astragalus (American groups) and Lotus.
Host Associations
- Astragalus - plantAmerican groups of Astragalus
- Lotus - plant
Ecological Role
Seed of leguminous plants; may be subject to competitive displacement by T. tectus, which appears to be extending its geographic and range at the expense of some semisquamosus group members.
Similar Taxa
- Tychius tectusMore closely allied to Eurasian relatives; has in Oxytropis and Eurasian groups of Astragalus; expanding range at expense of semisquamosus group members
- Tychius liljebladiMore closely allied to Eurasian relatives; has in Oxytropis and Eurasian groups of Astragalus; arrived in North America after semisquamosus group was established
- Tychius lamellosus (synonymized)Formerly described as distinct , now synonymized with T. semisquamosus
- Tychius squamosus (synonymized)Formerly described as distinct , now synonymized with T. semisquamosus
- Tychius intermixtus (synonymized)Formerly described as distinct , now synonymized with T. semisquamosus
More Details
Taxonomic history
T. lamellosus Casey, T. squamosus Hatch, and T. intermixtus Hatch were synonymized with T. semisquamosus LeConte in a 1977 revision.
Biogeography
Phylogenetic and plant relationships indicate Tychius arose in the Old World, with the semisquamosus group representing one of several independent dispersals from Eurasia that formed the North American fauna.