Panthalassa is out of Miss Pemberley (Montjeu), who raced seven times in Japan at three and was twice third. She has produced five winners from eight runners, among them Etendard (Deep Impact), second in the Gr.2 TV Tokyo Hai Aoba Sho, and the multiple Group-placed Dimension (Deep Impact), both in Japan. Miss Pemberley is a half-sister to two winners and to the unraced Strusuna (Grand Lodge), dam of Speed Of Sound and Agapunthis, both Listed-placed in Italy.

Second dam Stitching (High Estate) is a half-sister to Great Dane (Danehill), winner of the Gr.2 International Stakes in Ireland and later a sire, and to the Listed-placed miler Witching Hour (Alzao), second dam of the Listed winner Monte Alto. Another half-sister, the unraced Urgent Liaison (High Estate), is the dam of the Listed-placed Imoya and the third dam of El Topo, winner of the Listed Prix Montenica.

Third dam Itching (Thatching) was unraced and bred five winners, the best of them Great Dane.

The female line also includes Croco Rouge and Alidiva.

Miss Pemberley has a 2-year-old colt by Kizuna and a yearling colt by Rey de Oro.