Proneptunea, Thiele, 1912

Luca, Javier Di & Zelaya, Diego G., 2019, Gastropods from the Burdwood Bank (southwestern Atlantic): an overview of species diversity, Zootaxa 4544 (1), pp. 41-78 : 56

Proneptunea (?) minuta Castellanos, 1992

Fig. 4A

Proneptunea minuta Castellanos, 1992: 17 , pl. 1, fig. 1; Signorelli et al., 2015: 62

Examined material. 2 an. and 4 sh. (MACN-In 40694).

Description. Shell height to 4.3 mm (up to 4.7 mm according to Castellanos 1992); fusiform, delicate. Protoconch large, of 2 markedly convex whorls; sculptured with 3 low, wide spiral cords towards teleoconch. Teleoconch of up to 3.25 whorls, slightly convex in outline, with almost straight to slightly concave shoulders; last whorl comprising about 70% of total shell height. Suture impressed. Surface white; sculptured with 15 to 23 strong but narrow axial ribs per whorl, and spiral cords, wider than the axial ribs, 3 on the spire whorls, and 12 on the last whorl. Axial sculpture vanishing towards the base and shoulder, where numerous well marked growth lines are evident; 2 or 3 additional lower cords are present at the last whorls of large specimens. Aperture ovate, interior white; outer lip with markedly developed posterior (“anal”) canal; columellar callus narrow, slightly expanded on the base; siphonal canal short, almost straight, wide. Operculum absent.

Remarks. Thiele (1912) described Proneptunea based on radular characters. Powell (1951) attributed to this genus species with relatively large protoconch of straight sides, and having the operculum with terminal nucleus. The material studied here agrees with the original description of Proneptunea minuta . However, contrary to other species assigned to this genus, the protoconch shows convex whorls and the operculum is absent.

Figures

FIGURE 4: A. Proneptunea (?) minuta Castellanos, 1992, MACN-In 40694, scale bar = 1 mm. B. “Savatieria” meridionalis (Smith, 1881), MACN-In 40685, scale bar = 1 mm. C. “Savatieria” chordata Castellanos, Rolán & Bartolotta, 1987, MACN-In 40687, scale bar = 1 mm. D. Buccinidae sp., MACN-In 40686, scale bar = 1 mm. E. Fuegotrophon pallidus (Broderip, 1832), MACN-In 40690, scale bar = 5 mm. F. Trophon ohlini Strebel, 1904, MACN-In 40689, scale bar = 5 mm. G. Trophon plicatus (Lightfoot, 1786), MACN-In 40688, scale bar = 2 mm. H. Paradmete crymochara (Rochebrune & Mabille, 1885), MACN-In 40691, scale bar = 5 mm. I. Mangelia michaelseni (Strebel, 1905), MACN-In 40693, scale bar = 1 mm. J. Leucosyrinx angusteplicata (Strebel, 1905), MACN-In 40692, scale bar = 4 mm. K. Thesbia michaelseni (Strebel, 1905), MACN-In 40695, scale bar = 1 mm. L. Admete magellanica (Strebel, 1905), MACN-In 40696, scale bar = 3 mm.