Lophophorate's Flashcards
What are Lophophorates’?
Brachiopods and bryozoans
What are Brachiopods and Bryozoans united by?
The presence of a lophophore
What is a lophophore?
A complex feeding structure covered in cilia
which generates current and traps/direct food particles
How many genera of Brachiopods are there?
4500
Where are Brachiopod fossils abundant?
Palaeozoic deposits (especially shallow water and shelf deposits)
What dramatically affected the Brachiopods?
End Permian extinction but still have some importance in Mesozoic
What has been the population trend of brachiopods up to the present day?
Gradual decline with only about 100 genera at present
What are brachiopods?
A creature with a shall consisting of 2 valves (similar but different phyla to bivalved molluscs)
What are the differences between brachiopods and bivalves?
Valve structure
Orientation
Plane of symmetry
What is the plane of symmetry difference between brachiopods and bivalves?
Brachiopods - Bissects the 2 valves
Bivalves - runs between 2 valves
What is the orientation difference between brachiopods and bivalves?
Brachiopods - Dorsal (brachial), Ventral (pedicle)
Bivalves - Left and Right
What is the valve structure difference between brachiopods and bivalves involving the pedicle opening?
Brachiopods - have pedicle opening
Bivalves - no pedicle opening
What is the valve structure difference between brachiopods and bivalves involving the brachial skeleton?
Brachiopods have brachial skeleton
Bivalves no brachial skeleton
What does the pedicle opening say about the mode of life of a brachiopod?
Attached to the sea floor
What is the valve structure difference between brachiopods and bivalves involving the muscle impressions?
Brachiopods will have central muscle impressions 4 on pedicle and 2 on brachial
Bivalve 2 muscle impressions near exterior of shell
What 3 subphyla can brachiopods be divided into?
Linguliformea (late Cambrian to recent)
Craniiformea (late Cambrian to recent)
Rhynchonelliformea (late Cambrian to recent)
What are the characteristics of Linguliformea?
Chitinophosphate
Equivalved
Pedicle emerges between posterior edges
of valves
Lack teeth and sockets
What is the muscle insertion of Linguliformea like?
Adductors - oblique muscles
What is the a recent (best known) example of Linguliformea?
Lingula
What are the characteristics of Lingula?
Burrowing
Retracting pedicle pulling animal deeper into burrow
Euryhaline (short term)
What does euryhaline mean?
being able to tolerate a wide range of salinities
What are the majority of the brachiopods post the Ordovician?
Rhynchonelliforms
What are the characteristics of Rhynchonelliforms?
CaCO3 shell
Unequal valves
Pedicle emerges from pedicle opening in pedicle valve
Brachial valve brachidium
What are the muscles like in rhynchonelliforms?
Diductors which open valve (inserted behind hinge on cardinal process)
Adductors contract to pull valves together
What are the muscle scars like in rhynchonelliforms?
2 pairs in pedicle valve (adductor high and diductor low)
1 pair in brachial valve
What can the valve articulation of rhynchonelliforms be?
Hinge line in strophic (straight)
or
Non-strophic (curved)
What essentially are brachiopods?
Filter feeder enclosed in 2 valves
What are some examples of endofaunal brachiopods?
Burrowing - Lingula
Quasi-faunal = Waagenoconcha
(Permian)
What are some examples of epifaunal brachiopods?
Fixosessile encrusting e.g. Orbiculoidea
Fixosessile Plenipedunculate e.g. Terebratulids
Fixosessile Umbone cementing e.g. Prorichthofenia
Fixosessile Liberosessile e.g. Spirifer
What is the problem for a benthic mode of life for brachiopods and how was this solved?
Non-food entering the mantle cavity solved by a zig-zag anterior commissure
What is the age range of byrozoans?
Lower Ordovician to recent
What are some examples of the colony morphologies of byrozoans?
stick-like
encrusting
fan-like
How do byrozoans feed?
individual zooid extends lophophore out of chamber to gather food
How can byrozoans move themselves?
walking by using setae
