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“Trophon clenchi (Carcelles, 1953)
(Figures 101-114)
Murex clenchi Carcelles, 1953: 7, figs. 23-28; Castellanos, 1970: 80, pl. 5, fig. 7; Fair, 1976: 31, fig. 15; Vokes, 1992b: 24; Rios, 1994: 115.
Poirieria (Poirieria) clenchi (Carcelles).—Vokes, 1970: 18.
Description: Shell medium in size, delicate, thin, chalky, translucent white, protoconch known only from the holotype, asymmetrical, globose, of 2-2½ whorls; teleoconch of 5 shouldered whorls; spire short, less than ¼ of total shell height. Spire angle about 45º (without spines); suture impressed, subsutural shelf short, straight; aperture suboval, interior glossy white; anterior siphonal canal very long (longer than the aperture height), deep and slightly curved in the beginning and then straight, open but narrow; outer lip sharp, inner lip somewhat protruding, adpressed. Axial ornamentation of 7-9 regular axial lamellae growing across entire whorl surface, but attached to shell producing open, long and regularly spaced spines along periphery. Spiral ornamentation of 4-5 rounded cords on lower half of first whorls, becoming more than 20 in the last. Delicate growth lines present on entire shell surface.
Shell ultrastructure composed of two layers following the common pattern of the genus: innermost layer (40% of total thickness of shell) composed of crossed lamellar aragonite, outer layer (50%) of amorphous calcite. Sometimes, depending on the fracture mode, a basal aragonitic layer can be observed.
Radulae rachiglossate, rachidian teeth with three median cusps, the central one the larger and the lateral ones with a denticle, attached to the upper third of the interior margin of the lateral cusp; external margin with 2-3 obsolete denticles. Rachidian base sinuous, with the base offset under the proximal tooth. Marginal cusps single, never bifid. Lateral teeth curved, thin, with attachment area also thin (Figures 113-114).
Operculum triangular or suboval tear-shaped, attachment area elliptical, with horseshoe shape scars.
Type Material: 38°24' S, 55°36' W, off Mar del Plata, in 89.6 m, holotype and paratype (MACN-In 25146).
Additional Material Examined: 51°58' S, 56°38' W, 3 D, R/V ELTANIN Cruise 7, Sta. 558, 646-845 m (USNM 901774), 41°51' S, 57°34' W, collected by Uruguayan fishermen, June 2002, 1062 m, 1A, MACN-In 36270; approximately 45°10' S, 57°20' Uruguayan fishermen, 1 A, MACN-In 36269; 54°50' S, 63°50.5' W, 2.5 miles south Punta Fallows, Isla de los Estados, Tierra del Fuego, 1 A, R/V HERO Cruise 715, Sta. 715/879, 28 October 1971, in 342-353 m (LACM 71-331).
Distribution: Known from off Buenos Aires province, Patagonia and Isla de los Estados, in 90-1050 m depth.
Remarks: Carcelles (1953) described Murex clenchi from two shells he received from the crew of the ARA BAHÍA BLANCA, an Argentine Navy ship that occasionally collected material for the collection of the Museo Argentino de Ciencias Naturales (MACN). Both holotype and paratype were collected from the continental shelf off Buenos Aires province. This material remained housed at the MACN until it was sent on loan and it appears to have been lost for almost 30 years (see Castellanos, 1986). The return of the material to MACN made the type material again available for studies. Perhaps because of these facts, the ordinary quality of the illustration and the absence of soft parts, the species was always reluctantly considered as the southernmost representative of the genus Murex.
E. H. Vokes, in a fundamental paper published in 1970, stated that Murex clenchi belongs in the genus Poirieria sensu stricto. Rios (1994) considered M. clenchi as an anomalous specimen of Trophon acanthodes Watson, a species that slightly resembles some specimens of M. clenchi (e.g., the paratype).
The morphology of the shell as well as the radula and penis of Murex clenchi allow the allocation in the genus Trophon. In fact, this was already suggested by E. H. Vokes (1992b). After studying the material of T. acanthodes housed at the MACN she proposed that M. clenchi belongs to Trophon sensu lato and not to Poirieria. It bears no relationship with Poirieria despite some apparent shell similarity. As it is shown in Figure 112, Poirieria zelandica, type species of Poirieria, has no calcitic layer on the shell but a thick aragonitic one instead (Figure 112a). In contrast, the entire group of Patagonian Trophon (T. clenchi in particular), shows different degrees of development of the typical calcitic layer on the distinct species.
The range of the very few lots studied falls within the geographic distribution of other species of Trophon. Trophon clenchi was known from two quite different geographic and bathymetric areas: off Buenos Aires province (in about 90 m) and the slope off Patagonia. A new lot is recorded here from Isla de los Estados, which significantly increases the range of distribution of the species. It is possible that like other Patagonian species of the genus, T. clenchi would be associated to hard bottoms, thus hampering the collection of material. Its fragility, size, and inadequate sampling of the area adds other reasons for the scarcity of records. It is suggested that these variables accounts for the disjunt recorded distribution of this species. In fact, this species started to be repeatedly collected recently, when the fishery of the Patagonian toothfish (Dissostichus eleginoides) on the Argentinean slope provided the opportunity to catch accidentally entangled specimens (F. Scarabino, pers. comm.).”
(Pastorino, 2005: 71-74)
Trophon clenchi is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails.[1]
It can be found off of Argentina and Uruguay.[2]
Trophon clenchi is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails.
