First pholcommatine cobweb spider from Eocene Rovno amber, with a delimitation of the subfamily Pholcommatinae (Araneae: Theridiidae)

Rovnopholcomma wunderlichi gen. et sp. nov. is described from Eocene Rovno amber (Ukraine). The new genus is the closest relative of Succinura Wunderlich, 2008, known from the Eocene Baltic (Gdańsk Bay), Danish and Bitterfeld ambers. The controversial theridiid subfamily Pholcommatinae Simon, 1894 is here delimited and divided into two tribes: 1) Pholcommatini Simon, 1894, which includes the extant genus Pholcomma Thorell, 1869 and eight extinct genera, all known from the Eocene of Europe; and 2) Theonoini Simon, 1894, which includes the extant genera Theonoe Simon, 1881, Carniella Thaler & Steinberger, 1988 and Robertus O. Pickard-Cambridge, 1879. One of the key diagnostic characters for the newly delimited Pholcommatinae is the presence of hooded trichobothrial bases, a unique feature within the family Theridiidae.