Synaptida Cuénot, 1891

Davey, Nicola, 2014, First record of genus Paradota Ludwig & Heding in New Zealand waters and description of a new species (Echinodermata: Holothuroidea: Synaptida), Memoirs of Museum Victoria 72, pp. 1-4 : 2

Order Synaptida Cuénot, 1891

Diagnosis. ( Smirnov, 2012) As for subclass Synaptacea Cuénot, 1891.

“Usually worm-like Holothuroidea. Tentacles peltato-digitate, digitate, pinnate, or can be secondarily simplified, simple or forked. Radial canals absent; tubefeet and anal papillae absent; canals of tentacles extending from the ambulacral ring; ampullae of tentacles are not free hanging into the body cavity. No radial hemal canals. Ring muscles not interrupted by radial muscle bands. The suborder Synaptina has organs of balance (5 pairs of statocysts) in places where radial nerves extend from the neural ring. Topographically, the primary tentacles are arranged in the way that they were initially connected with the following now missing radial canals: two with medioventral, two with the left dorsal, and one–with the right dorsal. The stone canal is attached to the body wall and opens externally or terminates in the body wall or opens into the body cavity. Respiratory trees absent. The mesentery supporting the posterior loop of the intestine is attached to the body wall in the right ventral interradius. Longitudinal muscle bands are undivided. The calcareous ring is stout. The radial and interradial segments are usually similar in shape and size. Radial segments of the ring in their upper (anterior) part have a perforation for a nerve, or sometimes it is secondarily not closed on the top and is in a shape of notch (in paedomorphic species, the segments are simple, without an anterior projection, while the radial segments do not have a perforation, or a noch for passage of the nerve). Ossicles: myritrochid or chyridotid wheels, sigmoids, anchors and anchor plates. There are no tables.”

Figure 1A–D, Table 1.

Remarks. A recent review by Smirnov (2012) into the system of class Holothuroidea resulted in changes including four new subclasses and associated orders. The order Synaptida replaces what was previously known as Apodida Brandt, 1835 and it contains the two suborders Myriotrochina Smirnov, 1998 and Synaptina Smirnov, 1998 . Paradota belongs in the latter suborder and the Family Chiridotidae Østergren, 1898 .