Nesticus dilutus Gertsch, 1984

Fig. 23A-C

Nesticus dilutus Gertsch, 1984: 27, figs 94-96; Hedin and Dellinger 2005: 10, figs 13, 14.

Material examined.

New collections from type locality: USA - Tennessee, Rhea Co. • 2♂, 10♀; Grassy Creek Cave, south of Old Washington; 23 Aug. 1992; M. Hedin, J. Hedin leg.; Non type material: - Rhea Co. • ♀; Starve Rock Cave (TRH7); 26 Mar. 2016; K.S. Zigler, M.L. Niemiller, N. Mann leg.; KSZ 15-566 .

Diagnosis.

A close morphological and genetic relative of Nesticus tennesseensis . This species differs most conspicuously from the former in that the basal, dorsal process of the paracymbium is absent (Hedin and Dellinger 2005, fig. 13). The tegular apophysis has a narrow, L-shaped base with a gradually tapering tip, although this condition is found in some northern populations of N. tennesseensis (see Fig. 21B). Epigyna very similar to N. tennesseensis, but possess more widely separated, pointed medial margins when viewed dorsally (Fig. 23B, C) rather than the extended parallel medial margins in N. tennesseensis (Fig. 22B, D, F), and the overall shorter (anterior to posterior) epigynal plate. More troglomorphic (depigmented, lacking median eyes, with proportionately long legs) than all known populations of N. tennesseensis (see Hedin and Dellinger 2005).

Variation.

The female specimen from Starve Rock Cave has an epigynum very similar to specimens from the type locality.

Distribution and natural history.

This troglomorphic taxon was previously known only from the type locality (Grassy Creek Cave), but is now known from two nearby caves in east-central Tennessee (Fig. 13). Starve Rock Cave is very near Grassy Creek Cave and may share a subterranean connection.

Remarks.

Sister to Nesticus tennesseensis on UCE trees (Figs 3, 4), but N. dilutus sequences are embedded within a clade of N. tennesseensis sequences on the mitochondrial gene tree (Fig. 6). This latter pattern is attributed to either deep coalescence or gene tree estimation error.