Natsushima bifurcata

Material examined MOROCCO – Gulf of Cadiz • 3 cs; Jesuz Baraza mud volcano; 35 ° 35.439 ′ N, 07 ° 12.264 ′ W; 1105 m; 9 Jul. 2002; inside mantle cavity of Acharax gadirae; St. TTR 12 _ AT 391; DBUA 00711 • 1 af (damaged); Yuma mud volcano; 35 ° 24.973 ′ N, 07 ° 05.461 ′ W; 960 m; 2 Aug. 2004; inside mantle cavity of Acharax gadirae; St TTR 14 _ AT 524; DBUA 00765 • 4 cs; Yuma mud volcano; 35 ° 25.820 ′ N, 07 ° 06.330 ′ W; 1030 m; 29 May 2006; inside mantle cavity of Acharax gadirae; St TTR 16 _ AT 604; DBUA 00791.01 • 4 cs, 1 af; Yuma mud volcano; 35 º 25.046 ′ N, 07 º 05.450 ′ W; 975 m; 29 May 2006; inside mantle cavity of Acharax gadirae; St TTR 16 _ AT 605; DBUA 00791.02 • 2 cs; Ginsburg mud volcano; 35 ° 22.677 ′ N, 07 ° 04.979 ′ W; 920 m; 29 May 2006; inside mantle cavity of Acharax gadirae; St TTR 16 _ AT 607; DBUA 00791.03. Remarks Ravara et al. (2007) reported this species from cold seeps in the Gulf of Cadiz (Jesus Baraza, Yuma and Ginsberg MVs). The specimens were found in the mantle cavity of Acharax sp., which was later described as a new species, Acharax gadirae Oliver, Rodrigues & Cunha, 2011 (Bivalvia: Solemyidae) (Oliver et al. 2011). The bathymetric range of Acharax gadirae in the Gulf of Cadiz is 556 – 3902 m. However, only the populations from the mud volcanoes of the Western Moroccan field, located at depths of 920 – 1105 m, were infested by N. bifurcata. This species was originally found in the mantle cavity of Acharax johnsoni (Dall, 1891) from the Hatsushima and Okino-Yama cold seeps in Sagami Bay (E Pacific), at similar depths (1114 – 1170 m). Despite the great geographical distance, there were no substantial morphological differences between the specimens from the two localities that could justify the establishment of a new species. Aguado & Rouse (2011) obtained a COI sequence from one of the specimens from the Gulf of Cadiz (GenBank accession number JF 304492). However, the preservation of the Japanese specimens did not allow DNA analysis, and thus a molecular comparison was not possible. Ecology and distribution East Pacific (Sagami Bay, Japan) and NE Atlantic (Gulf of Cadiz), living inside the mantle cavity of chemosynthesis-based bivalves of the genus Acharax, from cold seeps at depths of 920 – 1170 m (Miura & Laubier 1990; Ravara et al. 2007).