(338TElic) Tetracanthella lichnidis (Bagnall, 1949)

*Tetracanthella strenzkei

Species of Tetracanthella are characterised by possession of four prominent anal spines. Tetracanthella lichnidis Bagnall was considered to be a junior synonym of Tetracanthella strenzkei Gisin, 1949 by Deharveng (1987). However, Tetracanthella lichnidis was described by Bagnall in a paper published in the Entomologist's Monthly Magazine on 11 March 1949. The late Peter Bellinger pointed out that in the absence of a definite publication date for Gisin's (1949) description of Tetracanthella strenzkei, it should be considered as 31 December 1949 under ICZN rules. Bagnall's name therefore has priority.

Tetracanthella lichnidis seemed confinded to the SW:  it was beaten from coniferous trees by Bagnall in July 1947 in the Princetown area of Dartmoor, and not refound until 2009 when Mike McDermott collected suspended soils from up trees in Whitewood, Devon.  Manual sorting on many bags produced 2 specimens of Tetracanthella lichnidis.  However a population of this species was collected by Peter Shaw from moss on a wall in Arncliffe, Yorkshire in September 2010; it is probably characteristic of organic-rich suspended soils.

It is black or dark blue, reaches 1.2 mm in length and has a distinctive hook-shaped mucro (Fig. 1). The empodial appendage of the foot is only about 0.2 times as long as the claw, and it has 2+2 macrochaetae on abd 3; by contrast Tetracanthella wahlgreni has a fused mucro, a larger empodium (c. 0.6* claw) and 3+3 macrochaetae on abd. 3.





Fig. 1: Furca of a paratype of Tetracanthella lichnidis collected from Princetown, Dartmoor in July 1947 by Bagnall. Note the mucro (mu) is hook-shaped. All the specimens in the NHML slide collection are in rather poor condition.

Tetracanthella lichnidis collected from suspended soils, White wood, Devon, June 2009 by Mike McDermott.

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