This document provides an introduction and overview of brachiopods including: - Brachiopods are marine invertebrates characterized by two valves and a lophophore used for filter feeding. - They are classified into two classes based on morphology and have been important fossils for understanding geological history. - Brachiopods diversified greatly in the Paleozoic era and were important for stratigraphy, though fewer species exist today.

1. Assingment on Geological history and Paleoecology of
BRACHIOPODS
Submitted To :-
Professor G.K.Sharma Sir
Head of department of
geology
Submitted by:-
Paras khati M.Sc 2nd
Semester
Roll no:- 190120680005

3. INTRODUCTION
 The brachiopods are a large group of benthic macro-
invertebrate and exclusively marine organisms
 They are characterized by two mineralized valves-on
the upper and lower surfaces
 Brachiopods are filter feeders which collect food
particles on a ciliated organ called the lophophore
 The most distinguishing features of brachiopods is
the presence of a pedicle- a fleshy stalk-like structure
that aids the animal in burrowing and maintaining
stability
 Most species of brachiopod went extinct during the
P-T Extinction 250 million years ago, but many
survive today

4. CLASSIFICATION
 Brachiopods have been divided into two class:
Articulata & Inarticulata
 Based on their external & internal morphology It is
further subdivided into six order
 The classification of articulate orders and suborders
depends primarily upon characters of the hinge and
beak areas (including hinge length, teeth and sockets,
pedicle opening, interarea, etc....) the nature of the
lophophore support
 Other features (such as the shell microstructure, surface
ornamentation) sometimes are quite diagnostic of
several orders and suborders of brachiopods.

5. MORPHOLOGY
Brachiopod Internal Morphology

6. Geological History
 Brachiopods have a very long history of life on Earth
(at least 550 million years). They first appear as fossils
in rocks of earliest Cambrian age, and their
descendants survive, albeit relatively rarely, in today’s
oceans and seas.
They were particularly abundant during Palaeozoic
times (248 to 545 million years ago), and are often the
most common fossils in rocks of that age.
Meristina
(Silurian)

7. Fossil brachiopods are useful tools for the geologist.
They are generally robust and relatively abundant,
and display considerable morphological diversity. In
some Palaeozoic rocks that formed in shallow water,
brachiopods are very abundant and may make up the
bulk of the rock in which they occur. They provide an
exceptionally rich record of almost the whole history
of an animal phylum, and are therefore valuable in the
study of evolutionary processes as well as in
palaeoecology, palaeobiogeography and stratigraphy.
They are particularly suitable for palaeoecological
analyses because of their occurrence in different
sedimentary facies. They lived on the sea floor where
marine sedimentary rocks form. They were evidently
susceptible to differences in environment as often
recorded by the surrounding sediments. Their shell
features reflect physiological differences relating to

8. They can also be useful stratigraphical indicators
and tools for correlation in sedimentary rocks
because certain lineages evolved relatively rapidly.
With a basic knowledge of brachiopods, a keen
observer can identify relative ages of strata to at
least the level of period, especially in Palaeozoic
rocks. More specialised knowledge is needed for
Mesozoic rocks because Mesozoic-aged
brachiopods show less external morphological
diversity and are relatively rare.
Influenced by such factors as water depth, salinity,
oxygen levels and static lifestyle, the distribution
patterns of fossil brachiopods provide a useful tool
in deducing the position of ancient shorelines and
the past distribution of land and sea.

9. Cambrian rocks characteristically contain a diverse and
abundant brachiopod fauna, at first completely
dominated by chitinophosphatic species but later
joined by various calcite-shelled forms. These prelude a
dramatic diversification such that brachiopods,
together with trilobites, are the primary stratigraphical
guide fossils in the shallow-water facies of the
Ordovician; they are also important in the Silurian and
Devonian.
In the Carboniferous, they have been of some
stratigraphical value, especially at a local level, when
combined with corals. Many major groups of
brachiopods became extinct at the end of the
Palaeozoic.

10. Terebratula
maxima,Charlesworth,1837
In the Mesozoic and
Cainozoic eras, the phylum
was much less diverse and no
longer dominated the shelly
faunas. However,
brachiopods give their names
to a number of zones and
marker beds, particularly in
the Jurassic. The youngest
well known brachiopod from
British rocks is Terebratula
maxima, a large terebratulid
from the Neogene Coralline
Crag of East Anglia.

11. Map showing the
main areas of
cambrian to
Neogene
sedimentary rocks in
britain. Colours
correspond with
those shown in the
geological column.

12. The main divisions
of earth history in
which brachiopods
have lived,
showing the
relative diversity of
the phylum through
time.Maximum
diversity is seen in
the Devonian.

13. Terebratulina lata, Etheridge,1881
gives its name to a zone in the
Turonian (Late Creataceous)
Torquirhynchia inconstans, J
Sowerby , 1821,gives its name
to a marker bed in the
Kimmeridgian (Late Jurassic)

14. Goniorhynchia
boueti, Davidson,
1852, gives its
name to a marker
bed in the
Bathonnian ( Mid
Jurasssic).

15. Paleoecology of
Brachiopods
Strophomenid brachiopod with
attached cornulitid worm
tube(Upper
ordovician,USA).Brachiopod valves
often serves as substrates for
encrusting organisms.
•Distribution and habitat
Brachiopods live only in the sea. Most species avoid
locations with strong currents or waves, and typical
sites include rocky overhangs, crevices and caves, steep
slopes of continental shelves, and in deep ocean floors.
However, some articulate species attach to kelp or in

16.  The smallest living brachiopod, Gwynia, is only about 1
millimetre (0.039 in) long, and lives in between gravel.[2]
Rhynchonelliforms (Articulata excluding Craniida),
whose larvae consume only their yolks and settle and
develop quickly, specialize in specific areas and form
populations that can reach thousands per meter. Young
adults often attach to the shells of more mature ones.
On the other hand, inarticulate brachiopods, whose
larva swim for up to a month before settling, have wide
ranges. Members of the discinoid genus Pelagodiscus
have a cosmopolitan distribution.
Interactions with other
organisms
The rates of metabolism of Brachiopoda are between

17. Brachiopod shells occasionally show evidence of
damage by predators, and sometimes of subsequent
repair. Fish and crustaceans seem to find brachiopod
flesh distasteful. The fossil record shows that drilling
predators like gastropods attacked molluscs and
echinoids 10 to 20 times more often than they did
brachiopods, suggesting that such predators attacked
brachiopods by mistake or when other prey was scarce.
In waters where food is scarce, the snail Capulus
ungaricus steals food from bivalves, snails, tube worms,
and brachiopods .
Among brachiopods only the lingulids have
been fished commercially, and only on a very small
scale. Brachiopods seldom settle on artificial surfaces,
probably because they are vulnerable to pollution. This
may make the population of Coptothyrus adamsi useful
as a measure of environmental conditions around an oil

18. Paleoecology and Valve Shape
• All brachiopods are filter feeding, sessile (non-mobile)
bottom dwellers.
• They are exclusively marine, but inhabit a variety of
bottom environments
at various depths and latitudes.
• Brachiopods are either free-living or rooted by their
pedicle to the
substrate. During life, they can be oriented either vertically,
inclined,
or horizontally to the substrate.
• Typically brachiopods oriented vertically during life will
have equally
biconvex shells, whereas inclined and horizontally
oriented ones will be
unequal inflation being plano-convex, concavo-convex

19. • Semi-Infaunal: oriented vertically (posterior
downward) and is only partially buried in the
sediment; they may or may not be attached by their
pedicle.
• Reclining: animal is in effect floating horizontally on
(or partially within) the sediment with the pedicle
valve as the lower valve.Generally, reclining
brachiopods have a concavo-convex or plano-convex
shape. The pedicle opening is usually not present.
• Epifaunal: the brachiopod is attached either to the
sediment or other object (e.g., marine plants) by their
pedicle.

20. Thank You
For this assingment
and watching