Ramazzottidae

Marley, Nigel J., Mcinnes, Sandra J. & Sands, Chester J., 2011, Phylum Tardigrada: A re-evaluation of the Parachela, Zootaxa 2819, pp. 51-64 : 60

Family: Ramazzottidae fam. nov.

Remarks. Another group requiring familial status comprises the genera Hebesuncus and Ramazzottius , which molecular data highlights as a distinct, well supported clade ( Kiehl et al. 2007; Sands et al. 2008b), and which we propose elevating to a familial rank of Ramazzottidae fam. nov., type genus Ramazzottius Binda and Pilato, 1986 . Both Hebesuncus and Ramazzottius have the Parachela asymmetrical double-claws (2121) with a variant on the Hypsibius - type claw, often referred to as Ramazzottius - type claw. Ramazzottius has the more extreme variant, where the external claw has a long basal section forming an arc with the secondary branch and a long, thin, straight primary branch. The external claws of Hebesuncus are less extreme. However, the AISM of both genera form blunt hooks, the dorsal being different from the ventral apophysis causing slight asymmetry with respect to the frontal plane ( Binda and Pilato 1986; Pilato 1987; Pilato and Binda 2010). In addition, both genera deposit eggs with a sculptured chorion, though this may not be a definitive familial character. The elongated buccal-pharyngeal tube of Hebesuncus is, in our opinion, of lesser systematic importance as it only defines the genus (see Kristensen 1987 vis-à-vis the Echiniscidae ).

The presence in Ramazzottius of the cephalic elliptical dorso-lateral sense organs could be symplesiomorphic with similar organs in Calohypsibius Thulin, 1928 , Paradiphascon and Halobiotus . These structures are possible analogues of the Apochela cephalic papillae (Prof. R.M. Kristensen, pers. comm.; see also Wiederhöft and Greven 1996; 1999); though their function(s) in the Parachela remain unclear.

Diagnosis. Hypsibioidea. The AISM comprises asymmetric, dissimilar dorsal and ventral “blunt hooks”. Claw pairs asymmetric (2121), external claw primary branch joins the secondary claw and basal section with flexible junction; primary branch may be very long and slender; the internal claw branches and basal section unified into a single rigid element. Eggs have a sculptured chorion and are deposited free in the environment.

Type genus. Ramazzottius Binda and Pilato, 1986 .

Composition. Ramazzottius , Hebesuncus Pilato, 1987 .

Etymology. Family name derived from the generic name Ramazzottius Binda and Pilato, 1986 .