Coronium wilhelmense (Ramírez­Bohme, 1981)

(Figs 27–29)

Trophon (Enixotrophon) wilhelmensis Ramírez­Bohme, 1981: 6, fig. 1. Trophon wilhelmensis – Pastorino, 2005: 74, figs 115–119.

Additional material examined

Off Valdivia, 39°50’S, 74°30’W, 500mm (dd).

Remarks

Originally described in Enixotrophon Iredale, 1929 (type species: Trophon carduelis Watson, 1882), Coronium wilhelmense was included in Trophon s.s. by Pastorino (2005: 74). He noted the striking resemblance of that species with Trophon acanthodes Watson, 1882, however, he distinguished it thanks to a single, but apparently stable, difference in shell morphology, i.e., the adapical upturned shoulder spines, and a slight difference in the morphology of the rachidian tooth of the radula.

The radula, illustrated by Pastorino (2005: figs 118–119), is more akin to Coronium as illustrated by Simone (1996: 50, fig. 12). The rachidian bears a narrow, long central cusp, short, narrow lateral denticles, clearly separated from the fairly long lateral cusps. The lateral teeth are narrow and long. In T. acanthodes the central cusp is broader, triangular, and the lateral denticles are very small, almost obsolete, attached to the interior margin of the lateral cusps, as observed in the other Trophon s.s. species.

Another reason why C. wilhelmense is here combined with Coronium is the typical multispiral protoconch with calcarella­like apical termination (Fig. 29), observed also in the three species of Coronium (Simone 1996, coll. RH). In T. acanthodes the protoconch is small, consisting of approximately two rounded whorls (Fig. 30), typical of Trophon s.s.