cold, deep waters 500 m, temperature around 4 to 6 C'

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Benthic ostracods divided into two major groups
Psychrospheric ostracods (bathyal and abyssal)
Thermospheric ostracods

• cold, deep waters ? 500 m, temperature around 4
  to 6 C.
• Large gt 1 mm in length-Animals is blind (eye
  tubercles are missing).
• Ornamentation is so dense.

• Thermospheric ostracods
• Shallow waters under less-dense, warm ( gt 10 C)
  waters
• Small
• Eye present.
• More diverse than the psychospheric ostracods

Legitimocythere
Cyprideis torosa
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Ecological variables

• Ostracods can be influenced ecologically by
  various factors such as
• Type of the substrate
• - Swimmers have smooth, thin, bean-shaped
  carapace.
• - Fine-grained (mud) dwellers have flattened
  ventral, wing-shaped carapace.
• - Coarse-grained (sand) dwellers have thick
  carapace with coarse ornamentation.
• - Interstitial ostracods are small, long and
  robust.
• Salinity
• Ostracods carapace morphology tend to vary
  according to variation in salinity.
• They occur in fresh water (0.0-0.5) of rivers
  and estuaries, brackish water (0.5-30) of
  lagoons and marshes, normal sea water (35-45)
  and hypersaline water bodies (up to 57) of the
  closed seas, lakes, lagoons and marginal bays.

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• Depth
• Populations of living pelagic forms increase
  with increasing the water-depth, whereas benthic
  forms show highest diversity near shallow waters.
• Psychospheric forms occur around 500 m depth.
• Thermospheric forms is restricted to the photic
  zone (0.0-150 m).
• Temperature
• Latitudinal temperature controls the shallow
  water forms.
• At tropical regions, faunas are more abundant
  and diverse than at the higher latitudes.

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Applications of ostracods
Occur in the sedimentary column since the Early
Ordovician, so they can be used as 1-
stratigraphic markers. 2- Paleo-salinity
indicators 3- Paleo-depth indicators
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Changes in the proportions of fresh- and
brackish-water ostracoda with inferred salinity
changes, from part of the Lower Headon Beds
(Modified from Keen, 1977).
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CLASSIFICATION Based on general shape, valves
overlapping, presence of ornamentation, hige
characteristics and male and female structures.
Ostracoda divided generally into five main
orders Order Archaeocopida Order
Leperditicopida Order Podocopida Superfamily
Bairdiacea Superfamily Cypridacea Superfamily
Cytheracea Superfamily Darwinulacea Order
Myodocopida Order Palaeocopida
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Orders Archaeocopida and Leperditicopida a)
Bradorai, b) Indiana, c) structure features of
leperditicopida and d) Leperditia. From Brasier,
1980.
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Order Podocopida (superfamily Bairdiacea) a-c)
Bairdia. From Brasier (1980).
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Order Podocopida (superfamily Cypridacea) a)
Cypris, b) details of Paracypris, c) Carbonita,
d) Cypridea and Argilloecia. From Brasier (1980).
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Order Podocopida (superfamily Cytheracea) a)
Limnocythere, b) Cytheracean muscle scar, c)
Cyprideis and d) Cytherura. From Brasier (1980).
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Order Podocopida (superfamily Darwinulacea) a-c)
Darwinula sp. From Brasier (1980).
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Order Myodocopida a) Richteria, b)
Entomoconchus, c) Thaumatocypris and d) exterior
LV of Jurassic species. From Brasier (1980).
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Order Palaeocopida a-b) Beyrichia, c)
Hollinella, d) Aechmina and e) Oepikium. From
Brasier (1980).
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HISTORY OF OSTRACODA (Stratigraphic position)
Diversity of ostracod taxa through time. Width of
bars corresponds to the number of genera, from
Brazier (1980).