1. Brachiopods—Stuff to know
Bold font terms in text
Classification and stratigraphic ranges of Classes and Orders
Be able to identify correct Order for any given specimen (not necessary to identify genera)
Fossils & Evolution—Brachiopoda

2. Fossils & Evolution—Brachiopoda
Living brachiopods
Fossils & Evolution—Brachiopoda

3. Fossils & Evolution—Brachiopoda

4. Fossils & Evolution—Brachiopoda

5. Fossils & Evolution—Brachiopoda

6. Fossils & Evolution—Brachiopoda

7. Brachiopoda—Phylum overview
Solitary (but individuals often live in clusters)
Bivalved, with each valve being bilaterally symmetrical
Marine; mostly shallow marine (100–200m), but can occur in depths >2000m
Attached by pedicle or unattached; some infaunal
Filter feeders
Fossils & Evolution—Brachiopoda

8. Brachiopoda—Phylum overview
Possibly share a common ancestor with bryozoans (both groups possess a lophophore)
Stratigraphic range is Early Cambrian to Recent
Peak diversity in Ordovician, Devonian, Permian
Major reduction coincident with end-Permian mass extinction
Mesozoic peak diversity in Jurassic
Fossils & Evolution—Brachiopoda

9. Fossils & Evolution—Brachiopoda
Brachiopod diversity
Fossils & Evolution—Brachiopoda

10. Fossils & Evolution—Brachiopoda
Classification
Fossils & Evolution—Brachiopoda

11. Brachiopod morphology
Ventral valve (a.k.a. “pedicle valve”)
Lower or bottom valve
Dorsal valve (a.k.a. “brachial valve”)
Upper or top valve
Foramen = pedicle opening (largely or entirely in pedicle valve)
Anterior = end of shell opposite foramen
Posterior = end of shell containing foramen
Commissure = line along which two valves meet
Hinge = articulation mechanism
Teeth in pedicle valve; sockets in brachial valve
Fossils & Evolution—Brachiopoda

12. Brachiopod morphology
Fossils & Evolution—Brachiopoda

13. Hinge, teeth and sockets
Fossils & Evolution—Brachiopoda

14. Brachiopod morphology
Shells may be highly ornamented
Growth lines (concentric)
Ribs (radial)
Fold (major raised area)
Sulcus (major depressed area)
Spines (sometimes extensions of growth lamellae; sometimes discrete structures)
Fossils & Evolution—Brachiopoda

15. Fossils & Evolution—Brachiopoda
Shell ornamentation
Fossils & Evolution—Brachiopoda

16. Features of the posterior region (pedicle and hinge region)
Pedicle opening
Delthyrium = triagular opening in pedicle valve
Notothyrium = smaller opening in brachial valve
Interarea = planar or curved surface between “beak” and hingeline
Ventral interarea
Dorsal interarea
Fossils & Evolution—Brachiopoda

17. Fossils & Evolution—Brachiopoda
Posterior region
“beak”
Fossils & Evolution—Brachiopoda

18. Posterior region (cont.)
Among articulate forms,
those with a hinge line
are strophic; those
without are astrophic
astrohpic
strophic
Fossils & Evolution—Brachiopoda

19. Fossils & Evolution—Brachiopoda
Internal features
Body cavity houses major organs in posterior region of shell
Mantle cavity in anterior region of shell is mostly open space
Lophophore = ciliated, arm-like structure that serves for respiration and food gathering
Pedicle = muscular stalk for attachment to external objects or substrate
Adductor and diductor muscles
Fossils & Evolution—Brachiopoda

20. Fossils & Evolution—Brachiopoda
Internal soft anatomy
Fossils & Evolution—Brachiopoda

21. Musculature (valves tend to close and stay closed upon death)
Fossils & Evolution—Brachiopoda

22. Fossils & Evolution—Brachiopoda
Lophophore
Usually a two-part structure, with each half (brachium; plural brachia) leading to the mouth
May be complexly looped or coiled
May be supported by a mineralized structure—spiralium (plural spiralia) or brachidium (plural brachidia)
Fossils & Evolution—Brachiopoda

23. Fossils & Evolution—Brachiopoda
Lophophore types
brachia
Fossils & Evolution—Brachiopoda

24. Fossils & Evolution—Brachiopoda
Lophophore supports
spiralia
looped
brachidia
looped
brachidia
spiralia
Fossils & Evolution—Brachiopoda

25. Fossils & Evolution—Brachiopoda
Class Inarticulata
Lingula ia an example of a “living fossil”
Relatively low diversity since Ordovician time
Infaunal, with long fleshy pedicle
Fossils & Evolution—Brachiopoda

26. Inarticulate brachiopods (Lingula et al.)
Fossils & Evolution—Brachiopoda

27. Fossils & Evolution—Brachiopoda
Order Orthida Strophic; unequally biconvex valves; usually with well-developed delthyrium/notothyrium openings in interareas
Fossils & Evolution—Brachiopoda

28. Fossils & Evolution—Brachiopoda
Order Strophomenida Strophic; convex ventral valve/concave dorsal valve
Fossils & Evolution—Brachiopoda

29. Fossils & Evolution—Brachiopoda
Order Strophomenida Strophic; convex ventral valve/concave dorsal valve (Suborder Productina)
Fossils & Evolution—Brachiopoda

30. Fossils & Evolution—Brachiopoda
Order Pentamerida Strophic or astrophic; strongly biconvex with incurved beaks; open delthyrium with spoon-shaped structure (“spondylium”)
Fossils & Evolution—Brachiopoda

31. Fossils & Evolution—Brachiopoda
Order Rhynchonellida Astrophic; biconvex shell with dorsal fold and ventral sulcus
Fossils & Evolution—Brachiopoda

32. Fossils & Evolution—Brachiopoda
Order Spiriferida Variable shell form; spiralia supports for lophophore (Suborder Spiriferina)
Fossils & Evolution—Brachiopoda

33. Fossils & Evolution—Brachiopoda
Order Spiriferida Variable shell form; spiralia supports for lophophore (Suborder Atrypina)
Fossils & Evolution—Brachiopoda

34. Fossils & Evolution—Brachiopoda
Order Spiriferida Variable shell form; spiralia supports for lophophore (Suborder Athyrina)
Fossils & Evolution—Brachiopoda

35. Fossils & Evolution—Brachiopoda
Order Terebratulida Astrophic (rarely strophic); biconvex shell; loop supports for lophophore
Cererithyris
(Jurassic)
Fossils & Evolution—Brachiopoda