Pholcomma Thorell

Pholcomma Thorell

Pholcomma Thorell, 1869,On European spiders, p. 98. Type species: Theridion projectum O.P.-Cambridge (= Pholcomma gibbum Westring).

Ancylorrhanis Simon, 1894, Histoire naturelle des Araignées,1: 592. Type species: Pholcomma hirsuta Emerton.

Small theridiid spiders. Carapace slightly longer than wide, highest behind eyes in thoracic region. Anterior eye row strongly procurved as seen from front,posterior row straight or procurved as seen from above. Laterals touching each other. Anterior medians smaller than others. Eyes in several species separated less than their diameter; spacing seems variable, however, in different individuals of same species. Chelicerae of varying length, anterior fang margin armed with two mesal teeth in addition to one or two near base of fang; posterior margin with two to four teeth; teeth small and may be visible only after examination with compound microscope. Sternum about as wide as long,truncate between posterior coxae which are separated by one to two times their length. Legs short; first and fourth subequal in length, third shortest. Metatarsi and tarsi of equal length or tarsi shorter. Small tubercle on retrolateral face of each patella. Tarsal comb indistinct or lacking. Setae of comb of P. hirsuta same size as other tarsal setae, serrations indistinct. Abdomen spherical to oval, longer than wide. Colulus consisting of two setae separated by almost their length. Two species {gibbum, hirsutum) heavily sclerotized, others (carota, barnesi) very lightly sclerotized. Males (of all four species known) with abdominal scutum covering whole dorsum, and scutum covering anterior half of venter. Males and females of equal size.

.Internal female genitalia with two seminal receptacles, a spherical widening of the connecting duct in some species (Figs. 18,24). Palpus with conductor (C in Figs. 16,21), median apophysis (M) and radix (R). Median apophysis apparently nonfunctional, lying only lightly against paracymbial hook (P) which is on ectal margin of cymbium. Attachment of haematodocha in basal half of cymbium. Shape of tegulum in several species more ring- or spiral-shaped, (Figs. 16,20, 37), than spherical.

The closely placed e},es,the high thoracic region of the carapace, and the general structure of the palpus suggest that this genus is close to Stemmops. The small size of Pholcomma, the paracymbial hook on the margin of the cymbium, and the structure of the chelicerae differentiate the two genera. Pholcomma can be separated from Paidisca in that the latter genus lacks a colulus and has the chelicerae with only one or two teeth on the anterior margin and no teeth on the posterior margin. The median apophysis of both Paidisca and Stemmops is functional, holding the bulb against the paracymbial hook of the cymbium.

Pholcomma, although heretofore known only from Europe and North America, seems to occur in other regions. Eri gone antipodiana Forster, 1955,Ree. Dominion Mus., 2: 198, Figs. 52-55,?,from Antipodes Island is a Pholcomma, Marples, Ree. Auckland Inst. Mus. (in press) describes a new genus from New Zealand whose type species is quite close to Pholcomma hirsuta of North America.

Pholcomma rostratum, Emerton, 1882,Trans. Conn. Acad. Sci., 6: 30, PL 6, Fig. 5, ♂ 1, is Floricomus rostratus, a linyphiid