Barnea (Anchomasa) truncata ( Say, 1822 )

Delfino, Marina & Signorelli, Javier H., 2021, Fig. 13 in Fig. 12. Majella pristis n in Periclimenaeus djiboutensis Bruce 1970, Zoological Studies 60 (28), pp. 1-20 : 4-7

Barnea (Anchomasa) truncata ( Say, 1822) ( Fig. 2D–F )

Synonyms [for complete list see Turner, 1954; here, only the selected combinations found in the most important literature are listed]

Pholas truncata – Say 1822: 321; G.B. Sowerby II 1849: 488, pl. 104, figs. 29–30.

Pholas (Cyrtopleura) truncata – Tryon 1862: 202; Lamy 1925: 87.

Barnea truncata – Dall 1889: 72, 1898: 816; Perry 1940: 88; Nicklès 1950: 232, fig. 454; Abbott 1954: 461; Moore 1961: 16; Barnard 1964: 565; Kilburn and Rippey 1982: 203; Kensley and Pether 1986: 209, fig. 14; Mikkelsen and Bieler 2004: 609; Ardovini and Cossignani 2004: 54, 292; Turgeon et al. 2009: 736; Velásquez et al. 2017: 254, figs. 12–13.

Barnea (Anchomasa) truncata – Turner 1954: 27, pl. 8, figs. 11–13; Huber 2010: 474; Cosel and Gofas 2019: 982–983.

Type locality: “southern coast of the United States ”, it was restricted to Charleston, South Carolina by Turner (1954).

Type material: Types was not found in ANSP cabinets. The specimen was deposited at the ANSP by Say itself. A probable syntype ( ANSP 50775) was illustrated by Turner (1954).

Description: Shell: medium to large, length up to 5 cm, thin, elongated, gaped at both ends, beaked anteriorly; external surface with radial ribs declining gradually, strong on the anterior slope, but almost smooth on the posterior side of the shell; dorsal margin slightly curved; umbonal reflection almost in touch with the umbos but anteriorly free; internally white, hinge plate without teeth, but with an apophysis, long, narrow, curved and ventrally projected inside each valve; dorso-anterior area covered by a thin protoplax, with parallel sides, not attached to the anterior adductor muscle.

Mantle cavity organs: Siphons totally fused, covered by the periostracum, extended almost ten times shell length, papillose tentacles surrounding both siphons; incurrent siphon with a row of single tentacles, excurrent siphon without tentacles; brownish pigmentation between tentacles, extended along the inner wall of the siphons; foot white and oval.

Material examined: United States of America ─ South Carolina ( ANSP 50775); Argentina ─ Bahia Blanca ( MACN 38385).

Distribution: Northwestern Atlantic Ocean, from Canada to Florida ( Bousfield 1960; Hebda 2011; Mikkelsen and Bieler 2007; Turgeon et al. 2009), Brazilian coast ( Rios 2009), Senegal to Congo ( Barnard 1964; Cosel and Gofas 2019), Bahía Blanca, Argentina ( Fiori et al. 2012, reported as introduced).

Remarks: Barnea truncata was widely found boring in wood, clay, and soft rocks ( Barnard 1964; Rios 2009; Díaz Merlano and Puyana Hegedus 1994). No synonyms of this species were found in the literature. It was recently reported as introduced in Bahía Blanca ( Fiori et al. 2012; Schwindt et al. 2020). Barnea (A.) truncata differs from B. (A) lamellosa in having a more anteriorly placed umbo, a posterior end more truncate and anterior margin slightly pronounced ( Fiori et al. 2012). This species was widely reported from eastern and western Atlantic Ocean. Genetic studies on specimens of Canadian ( Bousfield 1960; Hebda 2011; Mikkelsen and Bieler 2007; Turgeon et al. 2009; Turner 1954), African ( Barnard 1964; Cosel and Gofas 2019) and Argentine waters ( Fiori et al. 2012; Schwindt et al. 2020) will clarify this wide distribution range.

Figures

Fig. 2. A−C, Barnea (Anchomasa) lamellosa (d'Orbigy, 1841 in 1834–1847), NHMUK 1854.12.4.655, syntypes. D−F, Barnea (Anchomasa) truncata (Say, 1822), MACN 38385 from Bahía Blanca. G−J, Barnea (Anchomasa) subtruncata (G. B. Sowerby I, 1834, in 1821−1834), material collected by d'Orbigny in Payta, Perú, NHMUK 1854.12.4.656. The specimens of B. (A.) lamellosa and B. (A.) subtruncata with the apophysis broken. Scale bar = 1 cm.