Phylogenetic-relict
Guides
Cyclominae
Cyclominae is a subfamily of weevils (Curculionidae) comprising seven tribes: Amycterini, Aterpini, Cyclomini, Dichotrachelini, Hipporhinini, Listroderini, Notiomimetini, and Rhythirrinini. The subfamily exhibits a disjunct global distribution, with significant radiations in southern South America, southern Africa, Australia, and the western Mediterranean region. Phylogenetic studies indicate complex evolutionary relationships among constituent tribes, with some Palaearctic genera showing closer affinities to South American lineages than to geographically proximate relatives.
Horologion
Horologion is one of the rarest and most enigmatic carabid beetle genera, containing two known species of troglomorphic ground beetles endemic to the middle Appalachian Mountains. The genus remained monotypic for over 60 years after its description in 1932, with a second species discovered in Virginia in 1991 and described in 2024. Phylogenetic analysis places Horologion in supertribe Trechitae as sister to the Gondwanan tribe Bembidarenini, making tribe Horologionini a relict lineage with no close relatives in the Northern Hemisphere.
Ligia oceanica
sea slater, common sea slater, sea roach
Ligia oceanica is a large intertidal isopod reaching up to 35 mm in length, making it the largest species in the suborder Oniscidea. Native to rocky Atlantic coasts of Europe, it has been introduced to eastern North America and Atlantic islands. This semelparous species inhabits the supralittoral zone, hiding in rock crevices by day and emerging nocturnally to feed. Molecular phylogenetics suggests closer affinity to marine isopod suborders Valvifera and Sphaeromatidea than to terrestrial woodlice, challenging traditional classification.
Priacma serrata
Priacma bleach beetle
Priacma serrata is the sole extant species in the genus Priacma, a relict lineage of reticulated beetles in the family Cupedidae. Males are strongly attracted to the odor of bleach and other chlorine-based compounds, a unique behavioral trait that facilitates collection and study. The species exhibits pronounced sexual dimorphism, with females substantially larger than males and rarely encountered. Adult males possess non-functional digestive tracts and do not feed. Populations display episodic mass emergence events rather than continuous adult activity.