Rhadine
LeConte, 1846
Rhadine is a of (: Platyninae) described by LeConte in 1846. Many are troglobitic, restricted to cave in North America, particularly in Texas. Several species, including R. exilis and R. infernalis, are federally listed as endangered due to their restricted ranges and vulnerability to habitat disturbance. The genus is named after a figure from Greek mythology.
Pronunciation
How to pronounce Rhadine: /ˈrædɪni/
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Identification
Cave-dwelling are eyeless or have reduced , with elongated appendages typical of troglobitic . Specific identification requires examination of male and other subtle morphological characters; consultation of regional for North Platynini is necessary.
Images
Habitat
Deep caves with substrata of deep, uncompacted silt; troglobitic are obligate cave dwellers. Some species occupy specific microhabitats within cave systems.
Distribution
North America, with concentration of cave-dwelling in central Texas cave systems. Specific species have extremely restricted ranges limited to single cave systems or karst regions.
Behavior
Rhadine subterranea exhibits intrasex repulsion related to feeding, producing regular spacing patterns, counterbalanced by intersex attraction related to , producing contagion; the result is functionally random on suitable silt substrata.
Ecological Role
or scavenger within cave ; some are critically dependent on cave (Ceuthophilus secretus) as a food resource, either directly or indirectly through detrital .
Human Relevance
Several (R. exilis, R. infernalis) are federally endangered in the United States, subject to protection measures and management of threats such as () that disrupt cave .
Similar Taxa
- TrechusBoth are Platyninae with cave-dwelling ; Trechus is more diverse and widespread, with broader range including surface habitats; Rhadine is restricted to North America with more specialized cave .
- Other cave carabid genera (e.g., Anillinus, Darlingtonea)Convergent troglobitic (eyelessness, elongated appendages) requires careful examination of and detailed structural characters for differentiation.