Cyclocardia spurca Sowerby 1833
Creators: name: Güller, Marina
name: Zelaya, Diego G.
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Bivalvia
Carditoida
Carditidae
Cyclocardia
Cyclocardia spurca

description: Cyclocardia spurca (Sowerby, 1833)
Figs. 2 A–I, Appendix 2
Cardita spurca Sowerby, 1833: 195.
Cardita spurca Sowerby, 1833 —d’Orbigny, 1845: 581; d’Orbigny, 1847: pl. 82, fig. 13. Cardita spurca— Reeve, 1843: pl. 7, fig. 32.
Cardita spurca Sowerby, 1832 —Hanley, 1843: 146, pl. 18, fig. 16. Actinobolus spurcus [sic] [recte spurca] Sowerby—Adams & Adams, 1857: 487. Cardita spurca Yarell—Clessin, 1888: 37.
Cardita spurca Reeve—Clessin, 1888: pl. 13, fig. 5.
Cardita paeteliana Clessin, 1888: 20, pl. 6, figs. 7, 8.
Venericardia (Cyclocardia) spurca Sowerby, 1832 — Dall, 1903: 708. Venericardia spurca Sowerby—Dall, 1909: 261.
Venericardia paeteliana Clessin—Dall, 1909: 261.
Venericardia (Cyclocardia) spurca Sowerby—Lamy, 1922: 341. Cyclocardia spurca (Sowerby, 1832) — Dell, 1964: 192.
Cyclocardia spurca Sowerby, 1832 — Soot-Ryen, 1959: 38. Cylcocardia paeteliana Clessin, 1888 — Soot-Ryen, 1959: 39.
Type localities: Iquiqui, Perú [sic] [= Iquique, Chile], 6–10 fathoms [11–18 m] (Cardita spurca); Iquiqui [sic] [= Iquique, Chile] (Cardita paeteliana).
Material examined: 3 syntypes of Cardita spurca (NHMUK w/n); 2 lots (Appendix 2, Table 1). Other published records: Perú and Chile (d’Orbigny, 1845; Lamy, 1922) (Appendix 2, Table 2). Known distribution: Payta [05°S], Perú to Iquique [20°S], Chile. Dall (1909) and Dell (1964) reported Cyclocardia spurca from the Magellan Province, although no formal records from this area are known.
Description: Shell large (maximum observed L = 24.7 mm), rectangular (H/L = 0.85 ± 0.04 mm, n = 8), inequilateral, inflated (W/H = 0.83 ± 0.02 mm, n = 8), solid (Figs. 2 A–I). Anterior end slightly produced, lower than posterior end. Antero-dorsal margin markedly concave, sloping steeply. Anterior margin short, widely rounded. Ventral margin forming a wide curve. Posterior margin larger than the anterior one, almost vertical, straight to slightly curved. Postero-dorsal margin long, slightly convex, slightly sloping (Figs. 2 A–H). Lunule short, wide, deep; escutcheon elongated, narrow (Fig. 2 I). Beaks low, inflated, anteriorly located, anteriorly projected (Figs. 2 A–I). Prodissoconch unknown (eroded in examined specimens). Shell surface sculptured with 15–18 low, wide radial ribs, paved with elongated scales; interspaces narrower than radial ribs. Periostracum thick, dark brown (Figs. 2 A–F). Inner shell surface porcellaneous; inner margin crenulated, coincident with outer shell sculpture (Figs. 2 G, H). Pallial line continuous; anterior adductor muscle scar ovate; posterior adductor muscle scar reniform.
Hinge plate relatively narrow (Figs. 2 G, H). Right valve (Fig. 2 H): anterior cardinal tooth (CA3) hooked, with anterior part (CA3a) short and narrow, and posterior part (CA3b) with large triangular base. Posterior cardinal tooth (CP5b) long, straight, moderately solid. Anterior lateral tooth (LAI) small. Left valve (Fig. 2 G): two large and straight diverging cardinal teeth, the anterior (CA2a) ventrally directed, one third the size of the posterior one (CP4b). Anterior lateral (LAII) and posterior lateral (LPII) short, relatively solid. External ligament long and narrow, located on a nymph which extends for half the length of posterior part of dorsal margin (Figs. 2 G–I).
Remarks: The general shell outline of Cyclocardia spurca closely resembles that of larger specimens of C. thouarsii (Figs. 3 B, E) and C. velutina (Figs. 4 C, F). However, the former has a thicker and more inflated shell with stronger radial ribs and inflated beaks. In addition, C. velutina has a shorter postero-dorsal margin and C. thouarsii has long hair-like periostracal projections.
Although Paetel’s collection is currently housed at the ZMB, the type (s) of Cardita paeteliana were not found there (Zorn, C. in litt. June 8, 2012). The original description refers to an ovate, inflated and very solid shell, with the anterior end rounded and shorter than the posterior end, strong radial sculpture, and prominent beaks. This set of characters suggests that C. paeteliana is a synonym of Cyclocardia spurca.
description: Published as part of Güller, Marina & Zelaya, Diego G., 2013, The Families Carditidae and Condylocardiidae in the Magellan and Perú – Chile provinces (Bivalvia: Carditoidea), pp. 201-239 in Zootaxa 3682 (2) on pages 205-207, DOI: 10.11646/zootaxa.3682.2.1, http://zenodo.org/record/217328