Glypteuthria meridionalis ( E. A. Smith, 1881 )

Pastorino, Guido, 2016, Revision of the genera Pareuthria Strebel, 1905, Glypteuthria Strebel, 1905 and Meteuthria Thiele, 1912 (Gastropoda: Buccinulidae) with the description of three new genera and two new species from Southwestern Atlantic waters, Zootaxa 4179 (3), pp. 301-344 : 315-317

Glypteuthria meridionalis ( E. A. Smith, 1881)

Figures 8 A–L, 9A–D

Euthria meridionalis E. A. Smith, 1881: 29 , pl. 4, fig. 6; Rochebrune & Mabille, 1889: H61.

Euthria Glypteuthria meridionalis Smith. Strebel, 1905: 627 , pl. 21, figs. 11, 11a–d; Melvill & Standen, 1914: 122.

Glypteuthria meridionalis Smith. Thiele, 1912 , pl. 13, fig. 6, pl. 16, fig. 17 (radula); Powell, 1951: 138; Carcelles & Williamson, 1951: 297; Dell, 1972: 36, fig. 10; Castellanos, 1992: 19, pl. 1, fig. 11.

Buccinulum meridionalis ( E. A. Smith, 1881) . Forcelli, 2000: 92, fig.

Type material. Two syntypes, NHMUK 19.10.15.18–19 collected by HMS ALERT. Dell (1972: 36, fig. 10) illustrated the larger specimen as holotype, which constitutes a lectotype designation according to ICZN article 74.

Type locality. Portland Bay , St. Andrews Sound, 10 fms. [18.2 m] depth, and Sandy Point [ Chile] in 9–10 fms. [16.4–18.2 m] depth.

Description. Shell small, up to 11.5 mm in height, fusiform, of 6 slightly convex whorls; protoconch of about 1 1/2 convex whorls, with 5 to 6 spiral threads; suture impressed, slightly channelled; aperture elliptic; siphonal canal rather deep and short; parietal callus thin. Spiral ornamentation of 5 flat threads per whorl, about 20 on the last; axial sculpture of 14 rounded ribs (varices) that develop nodes when crossing the spiral threads. Periostracum translucent, very thin, producing a scaly appearance on the sulci between threads. Color brownish or reddish.

Operculum ( Fig. 8 L) pale yellowish, ovate-elliptical, nucleus subterminal, thick rim, small attachment area towards left side.

Radula ( Figs 9 A, B) rachiglossate, central tooth with three cusps, the central cusp largest; lateral teeth with two large curved, hook-shaped cusps with an obsolete cusp close to the inner one.

Penis large, flat, thick with a small papilla on the tip ( Figs 9 C–D).

Material examined. Argentina: 1 spm., Isla Becasses, Ushuaia , (MACN-In 35213); 1 spm., 53°39’24”S, 70°55’30”W, 24 m depth, ( USNM 898494 ) ; 3 spms., 53°39’S, 70°55’W, 20 m depth, (USNM 898491); 3 spms., Ushuaia, (MACN-In 40516); 2 spms., Bahia Ensenada, Ushuaia , (MACN-In 40517); 2 spms., 54°17.647”S, 66°15.376”W to 54°17.346”S, 66°15.531”W, 56 m depth, with bottom trawl, CAV2014, St. 22/48, (MACN-In 40518); 2 shells , Bahia Orange , Tierra del Fuego, Mission du Cap Horn, (MACN-In 13914-1). Chile: 3 shells, Punta Arenas, (MACN-In 12382).

Distribution. Only known from Tierra del Fuego and environs including the Straits of Magellan.

Remarks. The shell is similar to M. martensi ; however, the protoconch of this species is distinctive, with axial threads instead of the typical spirals. Strebel (1905) included four Magellanic species in his new genus, i.e. the type G. meridionalis , “ G.” martensi , “ G.” agnesia and “ G.” k o b e l t i. The only species belonging to Glypteuthria is the type species. G. agnesia is a synonym of Meteuthria martensi and G. k o b e l t i belongs in a different new genus proposed here: Falsimacme .

Powell (1951: 138, 1960: 148), Castellanos (1970: 98) and Dell (1972: 36) included Euthria acuminata Smith, 1915 in Glypteuthria ; however, this is a columbellid (according to the radula illustrated in Fernández & Castellanos, 1973), probably belonging in the genus Amphissa (sensu Rios, 1994: 124).

Castellanos (1970) included E. agnesia Strebel, 1905 in Glypteuthria . Fernández & Castellanos (1973) included what they called E. agnesia Strebel, 1905 in the columbellid genus Pyrene . Later Castellanos (1982) described the new species Amphissa cancellata (Columbellidae) to include this material that she considered previously as E. agnesia .

Dell (1972) suggested Lachesis euthrioides Melvill & Standen, 1898 as a synonym, however this is a valid species, dealt with here in the new Prosiphiinae genus Argeneuthria .

Figures

FIGURE 8. Glypteuthria meridionalis (E. A. Smith, 1881). A – C. Euthria meridionalis E. A. Smith, 1881, Lectotype, Portland Bay, St. Andrews Sound and Sandy Point, NHMUK 19.10.15.18 – 19. D – E. Paralectotype, NHMUK 19.10.15.18 – 19; F – G. 53 ° 39 ’ S, 70 ° 55 ’ W, USNM 898491. Scale bar = 5 mm. H. Detail of the spiral ornamentation, scale bar = 400 µm. I – K. Three views of the protoconch of the same specimen, scale bar H, J = 500 µm; I = 200 µm. L. External and internal view of the operculum, scale bar = 500 µm.

FIGURE 9. Glypteuthria meridionalis (E. A. Smith, 1881). A – B. Two views of the radula, scale bars = 20 µm. C. Penis, critical point dried, scale bar = 1 mm. D. Detail of the tip of the penis with papilla.