Shinkaiya, Lecroq & Gooday & Tsuchiya & Pawlowski, 2009

Lecroq, Béatrice, Gooday, Andrew John, Tsuchiya, Masashi & Pawlowski, Jan, 2009, A new genus of xenophyophores (Foraminifera) from Japan Trench: morphological description, molecular phylogeny and elemental analysis, Zoological Journal of the Linnean Society 156 (3), pp. 455-464 : 457

SHINKAIYA GEN. NOV.

Type species: Shinkaiya lindsayi gen. et sp. nov.

Generic diagnosis: Large xenophyophore: at least 8 cm in diameter and 5-cm high. Test fragile, approximately cylindrical in shape, and forming tightly-meshed, reticulated structure composed of bar-shaped elements (~ 0.5 cm in diameter), separated by open spaces. Test with smooth outer surface; wall relatively thick, soft, weakly cemented, and composed of fine sediment particles. Scattered internal xenophyae (agglutinated particles), mainly radiolarian tests, present.

Derivation of name: The name of the new genus is derived from the Japanese submersible Shinkai 6500, operated by JAMSTEC, which was used to collect the specimen.

Remarks: The new genus resembles species of the genus Syringammina , in particular the type species Sy. fragilissima . The genera are similar in the general shape and construction of the test, which consists of a framework of bar-like elements, forming a tightlymeshed, often reticulated structure. Another species, Syringammina reticulata Gooday, 1996 , has a similar arrangement of test elements, although the body form is flattened rather than domed. The main morphological difference between the new genus and Syringammina is the nature of the test wall. In Syringammina , the wall is brittle, with a smooth inner surface, and consists of ‘tightly cemented xenophyae’ ( Tendal, 1972). These comprise mainly fine sand grains and small foraminiferan tests in Sy. fragilissima . Shinkaiya , on the other hand, is characterized by a relatively thick wall that is soft rather than brittle, and consists mainly of clay-sized sediment particles. Unlike Syringammina , in which the particles are confined to the test wall, the lumen of the test in Shinkaiya includes scattered internal xenophyae. Our distinction of these two genera is supported by molecular data showing an important genetic distance between Sh. lindsayi sp. nov. and Sy. corbicula . Unfortunately, DNA sequences are not yet available for Sy. fragilissima .