A Review of Yorkshire Pseudoscorpions

C. A. Howes

Museum and Art Gallery, Doncaster

William Falconer’s (1862-1943) important contribution to arachnid systematics, “Key to the Families and Genera of British Spiders and to the Families, Genera, and Species of British Harvestmen and Pseudoscorpions” (Falconer 1910), stimulated and made practicable the scientific study of arachnida in Yorkshire, a study first pioneered in the 1670’s by Martin Lister, father of arachnology. Falconer’s extensive work, based partly on Rev. O. Pickard Cambridge’s paper “On the British Species of False Scorpions” (1892), made available an up-to-date and accessible key for amateur naturalists, “who”, wrote Falconer, “had hitherto been beset by the lack of accessible and comprehensive literature on the subject”.

Although pseudoscorpions have probably received more attention and are better recorded in Yorkshire than in most counties, they have never been intensively worked and still remain a very neglected and little known group. In 1909 the Arachnida Committee of the Yorkshire Naturalists’ Union was established under the chairmanship of William Falconer and an era of active collecting and recording commenced. With the help of such eminent naturalists as H. Britten, T. Stainforth, G. B. Walsh and W. P. Winter, data on most of the British groups of arachnida accumulated, to be compounded with earlier work by the indefatigable Falconer, to form a series of excellent and useful reviews. First to appear was “The Harvestmen and Pseudoscorpions of Yorkshire”, published in 1916, which even today remains the standard and only detailed work on the distribution and ecology of these orders in Yorkshire.

Today, twelve of the twenty-six species known to occur in the British Isles are recorded for Yorkshire. H. Wallis Kew, in his paper “North of England Pseudoscorpions” (Kew 1903), listed only four species for Yorkshire — Chthonius ischnocheles (Herm.), Neobisium muscorum (Leach), Dactylochelifer latreillei (Leach) and Lamprochernes nodosus (Schrank) — and made a plea for naturalists to take more note of this fascinating and compact little group.

Falconer (1916) included a further four species for Yorkshire — Cthonius tetrachelatus (Preyss), Cheiridium museorum (Leach), Allochernes dubius (O. P.-C.) and Toxochernes panzeri (C. L. Koch) — and expressed the belief that it was improbable that any more species would be added. Subsequently four additional species have come to light, Pselaphochernes scorpioides (Hermann), Chthonius orthodactylus (Leach), Chernes cimicoides (Fab.) and Lamprochernes godfreyi (Kew).

Today our knowledge of pseudoscorpions is still very superficial. With so little attention being paid to these captivating creatures, there is a great deal of scope for original work, even of a most elementary nature, on their distribution, ecology and life histories. The excellent papers by P. E. Jones (1970) on Chthonius ischnocheles and Lamprochernes nodosus are model studies which naturalists could usefully extend.

The field is wide open and every record is valuable. 

The following list indicates the records in Falconer’s 1916 review, brings together all subsequent records and information, and attempts to give some idea of the frequency, distribution and general habitat requirements of the currently-known Yorkshire pseudoscorpions. The arrangement and nomenclature follows that used by Beier (1932) and adopted by Evans and Browning (1954).

Order PSEUDOSCORPIONES Pavesi.
   Suborder Chtoniinea Beier.
     Family Chthoniidae Hansen.
        Chthonius tetrachelatus (Preyss), (Ephippiochthonius tetrachelatus (Preyss) )

A widely distributed species in Britain and Ireland, though apparently more abundant near the sea. Occurs in woods, outhouses, greenhouses, old gardens etc. in moss, under stones, amongst leaf litter and rotting vegetable matter.

Recorded from V. C. 61 and 63 (Falconer 1916) and subsequently V.C. 62.
  (61) Spurn Peninsula 26-28/5/1928 (Nat. 1928, 276).
  (62) Though no specific records are cited, it is recorded as “common near the sea” in Nat. Hist. Scar. Dist. 2, 331.
  (63) Sheffield 1922 (Nat. 1923, 24).

C. ischonocheles (Hermann), ( = C. rayi L. Koch).

An abundant and widely distributed species in Britain, occurring in a variety of situations, e.g. woods, quarries, cellars and outhouses where it can be found under stones, amongst leaf litter and decaying vegetable matter.

Recorded from V.C. 61, 64 and 65 (Falconer 1916) and subsequently V.C. 62.
(61) Spurn and Easington 25-26/5/1928 (Nat. 1928, 276).
(62) Spaunton Moor, August 1958 (Cloudsley-Thompson 1960).
Recorded as common in the Scarborough district, though no specific records are cited (Nat. Hist. Scar. Dist. 2, 331).
(65) Grinton, near Reeth -/5/1920 (Nat. 1920, 255).

C. orthodactylus (Leach).

Considered by Evans and Browning (1954) to be a southern species occurring under stones and among decaying vegetation.

(61) The only record for Yorkshire is from Spurn Peninsula in June, 1950, where it was noted as being uncommon (Nat. 1953, 171). On shingle and dune, amongst seaweed and tidal debris, under stones and amongst the roots of Marram grass.

  Suborder Neobisiinea Beier
    Family Neobisiidae Chamerlin
      Neobisium muscorum (Leach) ( = Obisium muscorum Leach).

Probably the most abundant, widely distributed and well known British pseduoscorpion. It is commonly found in leaf litter, rotting vegetation, moss, and under stones, and has been recorded many times from all the Yorkshire vice-counties.

(61) Allerthorpe Common -/1 1/1938 (Nat. 1938, 335).
(62) Skelder 22/2/1937 (Nat. 1937, 278), Whitby 2/1/1938, Mulgrave Woods 29/1/1938, Goathland 5/3/1938 (Nat. 1938, 335), Scarborough District 1966, per D. Whittaker.
(63) Bingley, Marden Valley 13/5/1922 (Nat. 1922, 231), Denshaw, commonly per P. Skidmore, Sheffield Museum garden 26/5/1964, and 21/5/1969, Blackmoor 26/5/1964, per Sheffield Museum. Thorne Moors, commonly in Sphagnum.

Sandall Beat Wood N.R. common in leaf litter; C.A.H.

(64) Austwick, winter 1920 (Nat. 1921, 167). Fountains Fell (2150 ft.) 22/5/1964, Tarn Moss (1200 ft.) 25/9/1961 and 20/6/1964, per P. Jones.
(65) Mill Gill and Witfield Forces, 7-9/6/1919 (Nat. 1919, 306), Reeth area -/5/1920 (Nat. 1920, 255).

  Suborder Cheliferinea Beier
    Family Cheiridiidae Chamberlin
      Cheiridium museorum (Leach)

The smallest of the British pseudoscorpions measuring from 1-1.5 mm. in length. It is a widely distributed species occurring in a variety of situations, e.g. under loose bark, in birds nests, bat roosts, barns, haylofts, stables and old derelict dwellings and warehouses. Recorded from V.C. 61 and 63 (Falconer 1916); there have been no subsequent Yorkshire records.

    Family Cheliferidae Hagen
      Dactylochelifer latrei/lei (Leach), ( = Chelifer degeerii Koch)

A maritime species favouring sand dunes along the east coast of England and Scotland where it is generally collected from beneath drift wood. Falconer describes it also occurring in the sheathing at the bases of marram grass stems.

Recorded from V.C. 61 (Falconer 1916) and subsequently V.C. 62.

(61) Spurn peninsula, many records noted as common, collected from Kilnsey Warren, Humber Foreshore, Walker Butt Dyke, and Marsh meadows, June-August 1947-1950 {Nat. 1953, 171).
(62) Flixton (Nat. Hist. Scar. Dist. 2, 331).

  Family Chernetidae Menge
    Lamprochernes godfreyi (Kew) ( = Chelifer Chernes godfreyi Kew).

An infrequently recorded species occurring in manure and compost heaps. As with nodosus they attach themselves to the legs of flies, probably as a means of dispersal from breeding sites which may be of a potentially temporary nature.

(63) The first Yorkshire record was from Leeds in 1912 where a specimen had been taken from a decaying Begonia tuber sent from Cardiff (Nat. 1922, 44). One taken from the leg of a stable fly Stomoxys calcitrans (L.) in Bessacarr, Doncaster, 1/9/1970; C.A.H.

      Lamprochernes nodosus (Schrank) ( = Che/ifer nodosus Schrank).

A common and widely distributed species occurring in relatively temporary situations like manure and compost heaps, piles of grass cuttings and various types of leaf litter. Jones (1970) describes in detail the frequently observed habit of L. nodosus of clinging to the legs of flies as a means of phoresy. “The various stages with life-cycle of the pseudoscorpion L. nodosus and the fly Musca domestica occur at the same time. It would seem that, since M. domestica moves from one manure heap to another and, being an excellent means of transportation, Lamprochernes has adapted to utilise this method of dispersal.”

It has been recorded several times for Yorkshire, sometimes in large numbers.

Noted for V.C. 61, 62 and 63. (Falconer 1916).

(61) Bridlington 9/10/1925 on housefly leg; Brit. Mus. Coll.
(62) Falsgrave, Scarborough, 8-9 taken from the legs of a fly, 1913 (Nat. 1918, 43).

Saltergate, among refuse in a cattle shed 10/4/1937 (Nat. 1937, 278). Whitby 7/10/1937 (Nat. 1938, 335). Ellerburn Bank N.R., June 1968, attached to the leg of a fly; Dr. M. B. Usher. Well, Bedale 25/10/1968, one specimen from oats and barley residues infested with a variety of beetles and mites (Min. of Ag. Fish & Food).

(63) Huddersfield 1919 and 1920 on the legs of flies (Nat. 1921, 43).

      Pselapho chernes scorpioides (Hermann), ( = Chernes minutus Ellingsen)

Stated by Evans and Browning (1954) to be a southern species, occurring in vegetable refuse and in rubbish heaps etc.

(62) The only Yorkshire record is of one taken from a nest of the ant Formica rufa L. at Barnes Cliff, Harwood Dale 1924 (Nat. 1924, 140).

     Chernes cimicoides (Fabricius) ( = Chelifer geoffroyi Leach).

Abundant in south-east England under the bark of dead and decaying trees. Evidence of its occurrence north of the Humber has only recently come to light. The first Yorkshire-taken specimen is one collected by the late Arthur Smith, probably in the 1950’s, in the York area. The specimen came into the possession of Mr. D. Whittaker who brought it to the attention of the author for whom it was determined L by Dr. Gabbutt.

(64) Subsequent localised records are of a male and female taken from under the bark of a dead birch tree at Askham Bog 2/9/1965; Dr. P. Gabbutt.

     Allochernes dubius (O.P.C.) (=A. tuligreni Strand)

Occurs under embedded rocks, amongst loose stones and amongst vegetable debris. It has also been found attached to legs of harvest spiders.

Recorded from V.C. 61, 63 and 64 (Falconer 1916), and subsequently from V.C. 62.

(62) Hayburn Wyke -/8/1919 (Nat. 1920, 43).
(64) Leeds, under birch tree roots in Roundhay Park 1921 (Nat. 1922, 43-44).

     Toxochernes panzeri (C. L. Koch).

Occurs in many widely separated localities and situations; usually found among hay and other similar refuse in barns, stables, granaries, old buildings and birds nests, it has also been found beneath embedded rocks and flagstones.

Recorded from V.C. 63 (Falconer 1916), there have been no subsequent records.

I would like to thank Dr. Peter Gabbutt of the Department of Zoology, University of Manchester, for the determination of specimens, information on Chernes cimicoides, and for advice on nomenclature and systematics; Mr. Tim Riley, Keeper of Natural History at Sheffield City Museum, for data on pseudoscorpions in the natural history collections at Sheffield Museum; Mr. Phillip Jones for information on Yorkshire-taken specimens in collections outside the county; and Mr. Peter Skidmore for advice on the preparation of this paper.