Hesperorthis

Hesperorthis

▪ fossil genus
      extinct genus of brachiopods, or lamp shells, which as fossils are especially characteristic of Ordovician marine rocks (438 to 505 million years old). The plano-convex shell of Hesperorthis consists of two units (or valves), the brachial valve being flat and the pedicle valve convex. The shell has a radiating pattern of ribs and a relatively broad, triangular area at the dorsal shell margin.

* * *


Universalium. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Orthida — Hesperorthis martinsonii (Bassett, 1974) Zeitraum Kambrium bis Perm 540 bis 250 Mio. Jahre Systematik …   Deutsch Wikipedia

  • Ордовикская система — (период)         ордовик, вторая снизу система палеозойской группы, соответствующая второму периоду палеозойской эры геологической истории Земли [см. Палеозойская группа (эра)]. Подст         илается кембрийской и перекрывается силурийской… …   Большая советская энциклопедия

  • List of brachiopod genera — Taxobox name = Brachiopoda fossil range = Cambrian Recent image width = 250px image caption = Rhynchotella inconstans lived some 155 150 million years ago (mya) regnum = Animalia phylum = Brachiopoda phylum authority = Duméril, 1806 subdivision… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”