Meteuthria martensi ( Strebel, 1905 )

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 : 319-321

Meteuthria martensi ( Strebel, 1905)

Figures 11 A–K, 12A–E

Euthria Glypteuthria martensi Strebel, 1905: 630 , pl. 21, figs. 13, 13 a, b. Euthria Glypteuthria agnesia Strebel, 1905: 631 , pl. 21, figs. 14, 14 a, b, c. Meteuthria martensi (Strebel) . Thiele, 1912: 243, pl. 13, fig. 7, pl. 16, fig. 18; Powell, 1951: 149, fig. K62; Castellanos, 1992:

20, pl. 1, fig. 8 (only).

Meteuthria agnesia (Strebel) . Dell, 1971: 206.

Type material. [ Euthria Glypteuthria martensi ] the following lots, housed at the ZMH collection should be regarded as syntypes: 1 spm., Magellan Straits, Borja Bay, SE 6201 (1167); 3 spms., Puerto Harris, 10 fms [18.3 m] depth, SE 6193; 4 spms., Ebendaher, 15 fms. [27.4 m] depth, SE 6192; 3spms., Puerto Condor, SE 6208; 1 spm., Basket Is., M 108; 2 spms., Voilier Cove, 10 fms. [18.3 m] depth, SE 6216 (661); 2 spms., Ushuaia, 5 fms., [9.1 m] depth, M124; 2spms., Ushuaia, 10 fms. [18.3 m] depth, M122; 1 spm., Ushuaia, 12–15 fms. [21.9-27.4 m] depth, SE 6220 (786); this specimen ( Figs 10A–C ) is here designated as lectotype in order to preserve stability of nomenclature, in agreement with ICZN article 74. [ Euthria Glypteuthria agnesia ] 1 spm., Picton Is., Banner Cove, 3 fms. [5.4 m] depth, M 168.

Type locality. Ushuaia , Tierra del Fuego, Argentina, here selected.

Description. Shell small, up to 12 mm in height, fusiform, of five slightly convex whorls; protoconch ( Figs 11 J, K) of about 2 convex whorls, translucent with quite distinctive closely spaced axial threads overall, transition to teleoconch weakly defined; suture impressed, slightly channelled; aperture oval, labrum thick; siphonal canal rather deep, oblique and long; parietal callus thin; growth lines close spaced over the entire shell; spiral ornamentation of thick threads, 4 on the first two whorls, 5 to 6 on the others; axial sculpture of 13 to 15 varices, which develop nodes when crossing the spiral threads; periostracum translucent, yellowish to brownish; colour chalky whitish, some specimens darker.

Operculum ( Fig. 11 I), pale yellowish, shape ovate-elliptical, nucleus subterminal, attachment area towards left side.

Radula ( Figs 12 A–C) with rachidian teeth absent. Laterals triangular, Prosipho -like or fan shaped (basal plate with “handle”), with four major, slightly curved, cusps pointing towards the center of the ribbon, sometimes 2 to 3 very small cusps on the outer side of the teeth.

Penis large, flat, with a thick, blunt papilla rising from a cavity ( Figs 12 D–E).

Material examined. Argentina: 1 shell, 35°30’S , 53°10’W, 91.5 m depth, (MACN-In 15611); 1 shell, 35°42’S, 54°40’W, 128–138 m depth, (MACN-In 15827); 1 spm., 39°S, 58°W, about 600 m depth, (MACN-In 32893); 3 shell, 4 spms., Ushuaia, (MACN-In 40519); 1 spm., 54º51.596’S, 68º31.618’W, Tierra del Fuego, 25 m depth, (MACN-In 40521); 4 spms. , 55°6.26’S, 66°28.14’W, 71 m depth, (MACN-In 40520).

Chile: 1 shell, 52°41’S, 74°35’W, 188–247 m depth, ( USNM 898754 ) ; 1 spm., 1 shell, Rada Picton Is., 27.5 m depth, (MACN-In 35132).

Distribution. Straits of Magellan and Beagle Canal, Tierra del Fuego in shallow waters; off Buenos Aires in more than 100 m depth.

Remarks. This uncommon species was included by Strebel in Glypteuthria because of the similarity of its shell to that of G. meridionalis . However, the radula, as stated by Thiele (1912), is different enough to justify his new genus Meteuthria . In addition, the protoconch with axial threads is also quite distinctive. One syntype of Euthria agnesia Strebel , a very damaged specimen, (illustrated in Fig. 11 D–E) was the basis on which the two species were synonymized.

Figures

FIGURE 11. Meteuthria martensi (Strebel, 1905), A – C. Euthria Glypteuthria martensi Strebel, 1905, lectotype, Ushuaia, SE 6220 (786). D – E. Euthria Glypteuthria agnesia Strebel, 1905, syntype. F – H. 35 ° 42 ’ S, 54 ° 40 ’ W, MACN-In 15827; Scale bar = 3 mm. I. External and internal view of the operculum, scale bar = 500 µm. J – K. Two views of the protoconch, scale bar = 500 µm.

FIGURE 12. Meteuthria martensi (Strebel, 1905). A – C. Three views of the radula, scale bars = A, B: 20 µm; C: 30 µm. D – E. Penis and detail of the papilla. Scale bars D: 500 µm; E: 200 µm.

FIGURE 10. A – E. Anomacme smithi Strebel, 1905. A. MACN-In 35381, scale bar = 2 mm; B. radula, scale bar = 50 µm; C. detail of the marginal teeth, scale bar = 20 µm; D. operculum, external view, scale bar = 500 µm, E. protoconch, scale bar = µm. F – J. “ Anomacme ” multituberculata Castellanos, Rolán & Bartolotta, 1987; F. protoconch, USNM 870453, same scale bar as E; G. operculum, external view, scale bar = 500 µm; H: radula, scale bar = 100 µm; I. detail of the radula, scale bar = 10 µm; J. USNM 870453, scale bar = 1 mm.