Late Paleozoic brachiopod
faunas of the South Kitakami Belt, northeast Japan, and their paleobiogeographic and tectonic implications.
The Lower Jurassic brachiopod
successions in the I-LS are recorded in the uppermost Pliensbachian-Upper Toarcian interval, comprising a period of changes in long-term environmentol conditions (e.g.
The presence of trace elements in brachiopod
shells was reported by Jope (1965) and included Fe, Mg, Mn and Cu.
Crinoid, Bivalve, Brachiopod
, Fusulinid, Bryozoanal Calcareous Sandstone Facies (MF9): This facies is 3.77m thick.
This model has previously been used to describe growth in brachiopod
species (Peck et al., 1997; Ostrow, 2004).
The appearance of brachiopod
shells is similar to that of bivalves; however, brachiopods
are different anatomically from bivalves and are considered to be unrelated evolutionarily to Mollusca (Pennington & Stricker 2001).
An accurate field study has revealed brachiopod
, separate rugose and colonial coral, bryozoan, crinoids and cephalopod macrofossil frequency;.
A team of scientists analyzed more than 46,000 fossils from 52 sites and found that greater numbers did indeed help clam-like brachiopods
survive the Ordovician extinction, which killed off approximately half of the Earth's life forms some 444 million years ago.
Cuticle fragments of olenellid trilobites, for example, reveal minute pores and the details of terrace ridges (Butterfield and Nicholas 1996, figs 3.1-2), while shell layers from organo-phosphatic brachiopods
exhibit a concentric accretionary pattern and sometimes a porous or granular texture (Fig.
The section was sampled during fieldwork in 1987 as follows: pebbles from the basal conglomerate of the Ulgase Formation (N-62), lingulate brachiopod
shells from the Ulgase Formation (N-63 and N-63A), and basal lingulate shell coquina of the Kallavere Formation (N-60).
Predation by durophageous chondrichthyans explains the dorsoventral flattening of brachiopod
shells in an environment with low energy currents.