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Notes on Essex specialities. 4: the spider
Baryphyma duffeyi (Millidge, 1954) (Araneae: Linyphiidae)
PETER R. HARVEY
32 Lodge Lane, Grays, Essex RMI6 2YP
The money spider Baryphyma duffeyi (see Figs. 1 and 3) was first described by A.F. Millidge in
1954 as Praestigia duffeyi from specimens collected in the Flatford Mill area. Between 1956 and
1961 specialist courses on spiders were held annually at Flatford Mill Field Centre by what was 1ater
to become the British Arachnological Society. During these courses the spider was again recorded
in the marshes opposite Flatford Mill, at Judas Gap (about 1/4 mile east of Flatford Mill) and at
Havergate Island one mile south of Orford in Suffolk (Cooke 1962). In Locket, Millidge & Merrett
(1974) B. duffeyi was known to occur on salt marshes and brackish marshes on the east coast of
England from Suffolk to Kent. The spider has been searched for at numerous places on the coast
between Scolt Head, West Norfolk and Havergate but without success (E. Duffey in Merrett in
Bratton 1991). The overall situation has changed little since then, but fieldwork by the Essex Spider
Group (David Carr, Ken Hill, Ray Ruffell and the author) since 1986 has demonstrated that the
brackish salt marshes of the rivers that flow into the Essex coast and the Thames hold almost all of
the known British populations of this spider. Its European distribution includes Belgium, the
Netherlands and Germany (Merrett 1991). The spider is a Nationally Rare (RDB3) Red Data Book
species. These arc defined as taxa with small populations which are not at present Endangered or
Vulnerable, but are at risk. Usually such taxa are not likely to exist in more than fifteen 10km
squares of the National Grid (Bratton 1991). In county terms the spider is Essex Rare and Essex
Vulnerable, as defined using the criteria published for ants and harvestmen (Harvey 1998, 1999).
Like a number of other erigonine spiders, such as the widespread Walckenaeria acuminata (Plate
11), the adult male B. duffeyi has an extension to the head, in this case a characteristic forward
pointing protuberance (fig. 1). Even the female has a small cusp in the ocular area. The purpose of
these strange projections is unknown, although in some related species protuberances and grooves
Figure 1.Baryphyma duffeyi male, drawing by P.R. Harvey
Essex Naturalist (New Series) 17 (2000)