Ceratopera axi (Riedl, 1954) Den Hartog 1964

Ceratopera axi (Riedl, 1954) Den Hartog, 1964

(Figs. 11 D–11E)

syn. Proxenetes axi Riedl, 1954

syn. Ceratopera bifida Ehlers & Ax, 1974

New locality. Playa Cerro Chato, Parque Nacional de Santa Teresa, Departamento de Rocha, Uruguay (33°59’6.34”S, 53°31’48.99”W). Between algae (mostly filiform brown algae) on exposed rocks, between small brown algae on top of very flat, isolated rocks, partly embedded in sand (20/07/2004).

Known distribution. Gulf of Napels and Sicily (Riedl 1954); Galapagos Islands (Ehlers & Ax 1974); Falkland Islands and California (Karling 1986); Weddell Sea and La Réunion (Artois et al. 2000), New South Wales, Australia (Willems et al. 2004); Kerguelen (Willems et al. 2005a); New Caledonia (Willems et al. 2005b).

Material. Observations on a live specimen. Two whole mounts.

Discussion. The stylets of the Uruguayan specimens measure 86–90 μm, when measured axially and the bursal appendage is 56–64 μm long. Both structures, especially the stylet, are small compared to known measurements of this species: stylet between 70–180 μm, bursal appendage between 67–117 μm (see Willems et al. 2004, table 1; Willems et al. 2005a, b). Only in the specimens of the Galapagos Islands (Ehlers & Ax 1974), is the bursal appendage also less than 70 μm. Because the variation in the size of the stylet is relatively large, it is possible that we are dealing with a species complex (see Willems et al. 2005a, b). However, this should be examined in the future by a thorough morphological (and molecular) analysis.