Cyphophthalmi Simon, 1879

Bartel, Christian, Dunlop, Jason A. & Giribet, Gonzalo, 2023, An unexpected diversity of Cyphophthalmi (Arachnida: Opiliones) in Upper Cretaceous Burmese amber, Zootaxa 5296 (3), pp. 421-445 : 423

Suborder Cyphophthalmi Simon, 1879

Remarks. All specimens described here can be unequivocally identified as members of the opilionid suborder Cyphophthalmi due to the presence of (1) a scutum completum, (2) raised ozophores and (3) a single claw on each tarsus of all legs. The modern families Neogoveidae and Troglosironidae can be excluded from the outset as none of the amber specimens feature a row of ventral teeth on the claw of leg II. Due to their restrictive modern day distribution we assume the affinities of the amber specimens to lie with Stylocellidae , which is the main extant cyphophthalmid family in Southeast Asia today. However, extant Pettalidae are found in Sri Lanka (and on the southern continents) and may have been previously distributed across the Indian subcontinent. Ogoveidae is today restricted to West Africa ( Giribet & Prieto 2003). We want to point out that Burmese amber has been shown to contain some groups that are typically Gondwanan, as well as taxa found today in the Neo- or Afrotropics but not in Southeast Asia. Examples belonging to arachnids include some Laniatorean harvestmen ( Bartel et al. 2021) and the rare arachnid order Ricinulei ( Wunderlich 2017) . The cyphophthalmid family Sironidae is distributed across former Laurasian terranes (North America, Europe, the near East and Japan) and could potentially have inhabited other Asian regions which were in contact with the Sibumasu terrane during the Cretaceous ( Clouse et al. 2010; Metcalfe 2017). Therefore the remaining cyphophthalmid families Pettalidae , Ogoveidae and Sironidae should not a priori be excluded. Furthermore, all amber specimens examined herein appear to differ from the first described Burmese amber species Palaeosiro burmanicum . The fossil described by Poinar (2008) features relatively long ozophores in comparison with its small body size, circular spiracles and a large sternal gland on the first sternite: a unique combination of characters not seen in our new material.