What's in a name? The Tangled History of the "Charnwood Spider"

Like it or not, we need to start with some history (and taxonomy - sorry). 

Mastigusa diversa - a troubled past   See: https://wsc.nmbe.ch/genus/776/Mastigusa

• The name Cryphoeca arietina was first used by Thorell in 1871, having been previously misidentified as Hahnia pratensis by Menge. 
• This species was then identified as Cryphoeca diversa by Octavius Pickard-Cambridge in 1893. 
• In 1908 Pickard-Cambridge renamed it Cryphoeca recisam.
• In 1913 after wandering around Sherwood Forest, A.R. Jackson renamed it again as Tetrilus recisus (On some new and obscure British spiders. Transactions and Annual Report of the "Nottingham Naturalists' Society" 60: 20-49). 
• In 1937 Eugène Simon renamed it Tetrilus diversus, and in 1953 Locket & Millidge called it Tetrilus macrophthalmus.
• In 1986 Wunderlich changed the genus (again) to Mastigusa macrophthalma, based on taxonomic priority from the species name Tuberta arietina macrophthalma used by Chyzer & Kulczyński in 1897. 
• Which brings us to the taxonomic revision by Castellucci, Luchetti & Scharff in 2024, which suggested that UK specimens were likely to be a new species, Mastigusa diversa. (See: Charnwood Confusion Continues).

Enter DNA. Based on the results of Castellucci et al, my initial hunch was that UK specimens would end up as Mastigusa arietina. But this is Mastigusa we're talking about, and it's not that simple. M. arietina was about to disappear from the UK Checklist, not having been recorded for 100 years (UK specimens having been called ... M. macrophthalma - see above!). Thanks to the Tanyptera Project at the World Museum in Liverpool, DNA barcoding has now been carried out on specimens from across the UK. One of the specimens has in fact turned out to be M. arietina, but most UK specimens are Mastigusa diversa as predicted by Castellucci et al. But what about the Charnwood Spider? The Tanyptera Project says: 

"Mastigusa (Charnwood) - the DNA was sequenced successfully and at a high quality. ... Following these results, the results of your previous Mastigusa, and the papers you provided us, we are confident that this is likely Mastigusa diversa."

You would hope that this DNA-supported moniker now persists. The spider, nor its Spanish cousins ... doesn't care. 

With grateful thanks to Richard Gallon, BAS Spider Recording Scheme, for organizing this work and the Tanyptera Project at the World Museum in Liverpool for carrying out the DNA barcoding and funding it. 

Castellucci, F., Scharff, N., & Luchetti, A. (2023) Molecular systematics and phylogenetics of the spider genus Mastigusa Menge, 1854 (Araneae, Cybaeidae). Molecular Phylogenetics and Evolution, 107833. 

https://www.sciencedirect.com/science/article/pii/S1055790323001331