Darlingtonea

Valentine, 1952

Species Guides

Darlingtonea kentuckensis

Darlingtonea is a of cave-dwelling ground beetles (Carabidae) containing a single , D. kentuckensis. This trechine is to eastern Kentucky's karst cave systems, where it functions as a top terrestrial specialized for high-humidity subterranean environments. The genus exhibits extreme physiological specialization, with narrow humidity identified as a critical vulnerability to climate change.

Darlingtonea kentuckensis (10.3897-subtbiol.34.46348) Figure 2 by (photo by Dr. Matthew Niemiller) Boyd OF, Philips TK, Johnson JR, Nixon JJ (2020) Geographically structured genetic diversity in the cave beetle Darlingtonea kentuckensis Valentine, 1952 (Coleoptera, Carabidae, Trechini, Trechini). Subterranean Biology 34: 1-23. https://doi.org/10.3897/subtbiol.34.46348. Used under a CC BY 4.0 license.

Darlingtonea kentuckensis (10.3897-subtbiol.34.46348) Figure 7 by Boyd OF, Philips TK, Johnson JR, Nixon JJ (2020) Geographically structured genetic diversity in the cave beetle Darlingtonea kentuckensis Valentine, 1952 (Coleoptera, Carabidae, Trechini, Trechini). Subterranean Biology 34: 1-23. https://doi.org/10.3897/subtbiol.34.46348. Used under a CC BY 4.0 license.

Pronunciation

How to pronounce Darlingtonea: //ˌdɑːɹˌlɪŋˈtoʊniə//

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Identification

As a , Darlingtonea is distinguished from other trechine carabid genera by containing only D. kentuckensis. The is relatively large-bodied for a trechine cave at 7.3–7.7 mm. Specific morphological diagnostic features distinguishing Darlingtonea from related genera (such as Pseudanophthalmus) are not documented in available sources.

Images

Habitat

Mississippian karst hypogean in limestone caves of eastern Kentucky. occur in sand banks within caves characterized by constant temperature (~12–13°C) and near-saturated relative humidity (~95–100%). The inhabits caves along the escarpments of the Mississippian and Cumberland plateaus.

Distribution

Eastern Kentucky, USA; specifically the eastern flank of the Cincinnati arch karst system spanning nearly 200 square miles in south-central Kentucky. Documented from Wind Cave, Pulaski County, and 27+ across caves of the Mississippian Plateau, Pennyroyal region, and Southern Appalachians.

Similar Taxa

PseudanophthalmusBoth are trechine cave occurring in eastern North American karst systems; Darlingtonea is distinguished by its status and larger body size relative to many Pseudanophthalmus .

More Details

Physiological Specialization

Experimental studies demonstrate extreme humidity specialization: survival declines dramatically below 100% relative humidity, with beetles at 50–80% RH surviving no more than three days. Thermal is broader than expected for a troglobiont, with significant mortality above 20°C and complete mortality at 30°C within 24 hours, suggesting remnant physiological characteristics from ancestral epigean carabids.

Genetic Structure

Analysis of 81 individuals from 27 revealed 28 unique mitochondrial COI haplotypes with high genetic differentiation (FST) between populations. Three northernmost genetic clusters show high among-cluster variability despite close geographic proximity, indicating unidentified intra-karst barriers to . Landscape features such as river drainages were not predictive of genetic breaks.