About Gigantidas platifrons

Gigantidas platifrons is a deep-sea mussel that is common in hydrothermal vents and methane seeps in the Western Pacific Ocean. It is found in hydrothermal vents in the Okinawa Trough and cold seeps in Sagami Bay (Japan) and the South China Sea. Morever, it harbours methane-oxidizing bacteria in its gill, which help to transfer methane into material and energy to help it to thrive in such environments.

Animalia (Kingdom); Mollusca (Phylum); Bivalvia (Class); Autobranchia (Subclass); Pteriomorphia (Infraclass); Mytilida (Order); Mytiloidea (Superfamily); Modiolidae (Family); Bathymodiolinae (Subfamily); Gigantidas (Genus); Gigantidas platifrons (Species)

Bathymodiolus platifrons Hashimoto & Okutani, 1994

(Hashimoto et al., 1994)

Shell large, up to 115 mm long, rather thick and solid, inflated,modioliform, oblong rounded-triangular in lateralview, equivalve, inequilateral,heightllengthratio O.50-O.68, width/length ratio O.34-O.47. Umbones prosogyrated, often nearly subterminal, but mostly on the same plane with anterior end of the shell. Umbonal ridge prominent. Anterior end rounded, dorsalmargin slightly convex, postero-dorsal corner round, postero-dorsal margin slightly convex, posterior margin broadly rounded, ventral margin slightly concave or nearly straight, External surface smooth, dull white beneath periostracum, with fine growth linesin juvenileand subadult, but with developed irregularlyspaced growth lirae in adults. Periostracum yellow in juvenileand subadult specimens, but usually yellowish straw, yellow-brown or dark brown in adult specimens, or dark russet in.some specimens. No periostracalhairs present.

Ptati means flatand .frons forehead. Because of rather truncated appearance in frontal region of the shell, the name was chosen.

Okinoyama Bank and off Hatsushima Sitein Sagami Bay, the Iheya Ridge and the Izena Caldron in the mid-Okinawa Trough, The specimens attached to outcrops with byssus around diffused vents