Pareuthria fuscata Bruguiere 1789

Pareuthria fuscata (Bruguière, 1789)

Figures 1 A–Q, 2A–G

Buccinum fuscatum Bruguière, 1789: 282; Lamarck, 1822: 268; Deshayes & Milne Edwards, 1844: 164; Kiener, 1834: 20, pl. 8, fig. 24.

Fusus plumbeus Philippi, 1844: 108, (Fusus) pl. 1, fig. 3; Tomlin, 1932: 164.

Buccinum patagonicum Philippi, 1845: 68; 1849: 46 [also numbered 6], (Buccinum) pl. 1, fig. 11; 1855: 205; 1857: 95.

Buccinum antarcticum Reeve, 1846 pl. 5, sp. 30.

B. magellanicum Philippi, 1849, (Buccinum) pl. 1, fig. 14 (in error) [only fig. 15]; Philippi, 1849: 138.

Fusus rufus Homb. et Jacq. in Rousseau, [1854]: 107, [1848] pl. 25, fig. 3, non Brown, 1827 pl. 48, fig. 47.

Fusus hombroni Philippi, 1855: 206, new name for Fusus rufus Hombron & Jacquinot non Brown, 1827.

Tritonium schwartzianum Crosse, 1861: 174, pl. 6, fig. 9, 10.

Buccinum Campbel’li Filhol, 1880: 1094.

Euthria antarctica Reeve. Tryon, 1881: 150, pl. 72, fig. 228.

Fusus (Euthria) fuscatus, Bruguière. Watson, 1886: 209, partim.

Euthria (Pareuthria) plumbea Philippi. Strebel, 1905: 600, pl. 24, figs. 52–56, 59.

Euthria (Pareuthria) magellanica Philippi. Strebel, 1905: 601, pl. 24, figs. 57–68, 73.

Euthria (Pareuthria) fuscata Bruguière. Strebel, 1905: 611, pl. 24, figs. 69–72, 74–79.

Pareutheria fuscata var curta Preston, 1913: 218.

Euthria fuscata Brug. Cooke, 1917: 235, fig. 9.

Euthria fuscata Brug. curta Prest. Cooke, 1917: 235, fig. 10.

Pareuthria fuscata (Bruguière). Powell, 1951: 132; Pether, 1993: 279, fig. 2e; Forcelli, 2000: 96, fig.

Pareuthria magellanica (Philippi). Powell, 1951: 133.

Northia fuscata curta Preston, 1913. Carcelles & Williamson, 1951: 294.

Northia atrata (E. A. Smith) 1881. Carcelles & Williamson, 1951: 294.

Pareuthria plumbea (Philippi). Powell, 1951: 133; Forcelli, 2000: 95, fig.

Pareuthria plumbea (Philippi, 1844). Powell, 1960: 148; Pastorino & Penchaszadeh, 2002: 106, figs. 1–4, (egg capsules); Linse, 2002: 104, pl. 14, fig. 9.1.1–105 (juvenile radula); Zelaya in Häussermann & Försterra, 2009: 496, figs; Rosenfeld et al., 2015: 73, fig. 6B.

Pareuthria campbelli (Filhol, 1880). Powell, 1960: 148.

Paraeuthria (sic) plumbea (Philippi). Fernández, 1967: 138, figs. 1–3; Castellanos, 1970: 101; Castellanos & Fernández, 1976: 9.

Paraeuthria magallanica (sic) (Philippi). Fernández, 1967: 139, fig. 4; Castellanos, 1970: 102.

Paraeuthria magellanica (Philippi). Castellanos & Fernández, 1976: 10.

Paraeuthria fuscata (Bruguière). Castellanos & Fernández, 1976: 9.

Type material. [Buccinum fuscatum] probable holotype MHNG 1101/98; [Fusus plumbeus], [Buccinum patagonicum] not found in MNHNS; [Buccinum antarcticum] not found, probably in NHMUK; [Tritonium schwartzianum] holotype in MNHN; [Fusus rufus] syntype in MNHN; [Buccinum Campbel’li] unknown.

Type locality. [Buccinum fuscatum] no locality in the original description, later Kiener (1834) erroneously cited it from “ cost du Perú ”; [Fusus plumbeus] “ Orae australes Reipublicae Chilensis ”; [Buccinum patagonicum] “ fretum magellanicum ”; [Buccinum antarcticum] Falkland (Malvinas) Is.; [Tritonium schwartzianum] unknown; [Fusus rufus] “ détroit de Magellan ”; [Buccinum Campbel’li] coast of Campbell Is., New Zealand.

Taxonomic history. Bruguière’s description was based on material from Lamarck’s collection, which is housed at MHNG. The probable figured specimen, (MHNG 1101/98) from Kiener’s Iconographie is illustrated here in figures 1A, B. Kiener (1834) cited a picture from Knorr (1771, part 5, pl. 22, fig. 4, see Dijkstra (2010) for a collation of this book), a pre-Linnaean book in the synonymy of Buccinum fuscatum, however in the description the author reported a white line in the aperture, which is never present in P. f us cata.

One syntype of Fusus rufus collected from the Magellan Straits is housed at MNHN. This specimen, illustrated here in figures 1J–K, is in fact darker than usual but undoubtedly belongs to this species, as previously stated by Tryon (1881: 150) and Melvill & Standen (1914: 121). Philippi’s types of Buccinum patagonicum and B. magellanicum from southern Chile were not found at the MNHNS where most of the author’s South American material is housed. However, the pictures are of sufficient quality to consider both species under the synonymy of P. fuscata, as also mentioned by Tryon (1881: 150). Reeve’s species, Buccinum antarcticum, is the same, although the material was not found in the NHMUK. Tritonium schwartzianum Crosse, illustrated in figures 1C–D with no locality, despite the unusual large size of the shell, is another synonym. Both the latter names were recognized as synonyms by Powell (1951).

Description. Shell large (largest of the genus), up to 44.6 mm in height but usually about 30 mm, fusiform, of seven convex, subquadrate whorls; protoconch of 2 ½ to 2 3/4 convex whorls, translucent, completely smooth; transition to teleoconch weak but visible (Fig. 2 C); suture impressed, short subsutural ramp present, producing a subquadrate profile more pronounced on the last whorl of mature specimens; aperture elliptic with the posterior angle acute, outer lip thin, slightly reflected; siphonal canal deep and short; parietal callus very thin; growth lines irregularly and closely spaced over the entire shell; axial ornamentation, when present, 13 to 15 nodes at periphery sometimes developing into incomplete riblets or varices that only reach the middle of the whorl; spiral ornamentation absent in adult, some juveniles with about seven faint spiral striae on the base of the last whorl; periostracum thin, translucent or brownish. Shell color dirty bluish to plumbic grey, some specimens with a thin, indefinite subsutural white line; interior porcelainous white, particularly along apertural margin, or dark brownish. Operculum (Fig. 2 D) brown, ovate; nucleus subterminal, internally with a thick rim; attachment area ovate, lying towards left side.

Radula (Figs 2 A–B) rachiglossate, very consistent, central tooth with three cusps of similar size, base rectangular, strongly curved in the center; lateral teeth with a small base and two curved, hook-shape, cusps, the inner one smaller. Penis (Figs 2 E–G) large, long, sub-rectangular, flat with sharp tip; sub-terminal conical papillae rising from a hollow depression; tip of papillae with irregular sinuous margin (Fig. 2 G) (artifact?).

Pastorino & Penchaszadeh (2002) described the spawn of this species as Pareuthria plumbea.

Material examined. Argentina: Puerto Pirámide, Golfo Nuevo, Chubut, (MLP 3396); Golfo Nuevo, Chubut, (MLP 3404); 10 spms., Cabo Raso, Chubut, 44°16’8.23”S, 65°16’15.30”W, 2 m depth, (MACN-In 40510); Comodoro Rivadavia, (USNM 368991); about 50 spms., Comodoro Rivadavia, Chubut, (MACN-In 9032); Comodoro Rivadavia, 10 spms., (MACN-In 6829); 4 spms., Punta Marquez, Chubut, (MLP 27224); 1 spms., Puerto Mazarredo, Santa Cruz, (MACN-In 9197-4); 6 spms., Cabo Blanco, Santa Cruz, (MACN-In 23626); Isla de los Leones, Río Santa Cruz, Santa Cruz, (MLP 3400); Punta Roca, Puerto Deseado, Santa Cruz, (MLP 8959); Puerto Deseado: (MLP: 4723); (3407); (580); (4872); (4857); (4328); (4868); (27245); (4781); (4919); (4845); about 100 spms., (MACN-In 17736); (17748); (28965); (9193-13); 2 spms., (35116); (USNM 368995); 15 spms., Caleta Coyle, Santa Cruz, (MACN-In 1032); Monte Tigre, Rio Gallegos, (MLP 573); Punta Peñas, San Julián, (MLP 489); San Julián, (MLP 3412); Bahia San Julian, (MLP 2747); Restinga off Monte Tigre, Río Gallegos, (MLP 474); 11 spms., Cabo Domingo, Tierra del Fuego, (MACN-In 29614); about 100 spms., Puerto Hoppner, Staten Is., (MACN-In 22545); about 100 spms., Puerto Cook, Staten Is., 20 fms. [36.5 m] depth, (MACN-In 22085); 1 spm., Puerto Cook, Staten Is., 20 fms. [36.5 m] depth, (MACN-In 22104); 1 spm., 54°26’30”S, 64°53’W, 61 fms. [111.5 m] depth, (MACN-In 25033); 7 spms., 54°48’S, 67°55’W, 56 fms. [93.2 m] depth, (MACN-In 22712); 2 spms., 54°58’S, 64°52’W, (MACN-In 22660); Staten Is., (MLP 4866); 10 spms., Bahia de San Antonio, Puerto Parry, Staten Is., (MACN-In 27449-2); 4 spms., Bahia Vancouver, Staten Is., (MACN-In 22266); about 120 spms., Rio Grande, Tierra del Fuego, (MACN-In 12567); 7 spms. (MACN-In 6642); 4 spms., (MACN-In 30905); Bahía Golondrina, Ushuaia, (MLP 4867); (MLP 27241); Ushuaia, (MLP 4909); about 50 spms., (MACN-In 13585); 10 spms., (MACN-In 30875); 6 spms., (MACN-In 19869); 7 spms., (MACN-In 9237); 2 spms., Ushuaia, 27.5 m, (MACN-In 10044-1); Isla Observatorio, 16 spms., (MLP 4361); about 100 spms., (MACN-In 22584); Puerto Vancouver, Isla Observatorio, (MLP 4347); Puerto Presidente Roca, (MLP 4371); (MACN-In 21976); 11 spms., Puerto Stanley, Malvinas Is., intertidal, (MACN-In 10135); Puerto Stanley, Malvinas Is.: (USNM 368420), (421892), (368291), (36827), (368351), (368390); Mullet Creek, Malvinas Is., (USNM 368323); Teal Inlet, Malvinas Is., (USNM 368369); York Bay Port, Malvinas Is, (USNM 421887); 4 spms., Malvinas Is., (MACN-In 29414); Tierra del Fuego, (USNM 126898);

Chile: 12 spms., Calbuco, (MACN-In 21847-1); 15 spms., (MACN-In 21847); 3 spms., (MACN-In 10463); Puerto Hambre, Magallanes, (MLP 5577); 14 spms., Puerto Harris, Dawson Is., (MACN-In 12445); 12 spms., Paso Richmond, (MACN-In 24944); about 100 spms., Punta Arenas, (MACN-In 12369); 2 spms., (MACN-In 12140); 5 spms.(MACN-In 12369); 1 spm., (MACN-In 9040-19); Punta Arenas: (MLP 3414, 4869); (USNM 368647, 368758, 368749, 368762, 346854); Magallanes, (USNM 533789); Bahia York, (MLP 4345); Port Otway, (USNM 102335); Gregory Bay, (USNM 170186); Orange Harbour, (USNM 32349, 16993); Chiloe Is., (USNM 348500);

New Zealand: Campbell Is., between Meteorological Station and Lookout Point, Perseverance Harbour, 52°33’S, 169°11’E, (NMNZ 47421); Campbell Is., Tucker Cove, 52°33’S, 169°8.5’E, 2-4 m depth, (NMNZ 299038); 49°40’S, 178°53’E, 103 m depth, (USNM 870830); Campbell Is., (USNM 195285); Perseverance Harbour, Campbell Is., (USNM 824738).

Distribution. South of Buenos Aires province, Peninsula Valdes area, Chubut province, Santa Cruz province, to Ushuaia, Tierra del Fuego including Malvinas and Staten Is. in the Atlantic and, Southern Chile to Chiloe Is. in the Pacific; Campbell Is., New Zealand, Gough and Tristan da Cunha Is. (according to Pether, 1993, material not seen).

Watson (1886: 210), with some reluctance, recorded this species from St. 149b of the HMS CHALLENGER expedition (Kerguelen Is.). However, he mentioned the presence of “ much sharper…spiral threads ” on these specimens, which raises some doubt about the real identification of the material, as adult specimens of P. f us c a t a are completely smooth.

Pareuthria fuscata is probably the commonest species of the genus and has a very wide distribution. This is unexpected for a species with non-swimming larvae (lecithotrophic according to Pastorino & Penchaszadeh 2002). One probable explanation, as suggested by Pether (1993) could be rafting on kelp such as Macrocystis pyrifera, a fairly common algae in the southern area of distribution of this gastropod. This constitutes a natural substrate where the females lay the egg capsules. Successive colonization over long periods of time would allow for arrival to distant regions such as Gough or Campbell Is. Pether (1993) also recorded this species from Quaternary (13,500 years BP) deposits from the Orange shelf off the west coast of Southern Africa, proving sporadic colonization of that intermediate area in which it is absent nowadays. He discussed the presence of P. f u s c at a and some other Magellanic mollusks in these Quaternary deposits and the absence of P. f u s c a t a from the recent fauna of South Africa.

Remarks. Tryon (1881) included Buccinum ferreum Reeve, 1847 as a synonym of P. plumbea. The type material of Reeve’s species was studied at the NHMUK (1996380, two syntypes from Japan). Also, Cernohorsky (1971: 162, figs 83–84) illustrated the larger syntype, including the species in the genus Japeuthria, which has neither morphological nor geographical relations to Pareuthria.