An Illustration by Mary Williams of a Silurian Stegerhyncus brachiopod based on specimens of Stegerhyncus and other closely related species from the Chicago area and Waldron, Indiana.
An Illustration by Mary Williams of a Silurian Stegerhyncus brachiopod based on specimens of Stegerhyncus and other closely related species from the Chicago area and Waldron, Indiana.

BRACHIOPODS are relatively rare animals today and live only in seawater. They were much more abundant in seas of the Silurian Period. Brachiopods have a shell made of two halves. Each half of the brachiopod shell has a slightly different shape (figures 10a - 10d). Brachiopods feed by filtering tiny food particles from seawater. Most of the space inside the brachiopod shell is occupied by a special organ that acts as a water pumping and filtering device. Brachiopods do not move very much. Most are held to the bottom by a stalk (reconstructed in figure 10b). Some Silurian brachiopods lacked a stalk, had a flattened shell form (figure 3b), and rested freely on the seafloor.

At least 43 species of brachiopods represent the most diverse group of dwellers in the Silurian reefs of Wisconsin and Illinois. The ten species with asterisk can be found in the Silurian reef diorama.


Kingdom: Animalia
Phylum: Brachiopoda

Class: Order: Family: Genus and species

37. Lingulata: acrotretid
38. Lingulata: Disciniidae: Orbiculoidea sp.
39. Craniata: Craniida: Craniidae: Philhedra magnacostata (Grubbs)
40. Craniata: Trimerellida: Trimerellidae: Dinobolus conradi (Hall)
41. Chileata: Dictyonellida: Eichwaldiidae: Dictyonella reticulata (Hall)
42. Strophomenata: Orthotetida: Coolinia subplana (Conrad)
43. Strophomenata: Orthotetida: Triplesiidae: Oxoplecia niagarensis (Hall & Clarke)
44. Strophomenata: Strophomenida: stropheodonitid
45. Strophomenata: Strophomenida: Leptestiidae: Leangella sp.
*46. Strophomenata: Strophomenida: Rafinesquinidae: Leptaena depressa (Sowerby)
47. Strophomenata: Strophomenida: Strophomenidae: Pentlandina glypta (Hall & Clarke)
48. Strophomenata: Strophomenida: Sowerbyellidae: Plectodonta sp.
*49. Strophomenata: Strophomenida: Leptostrophiidae: Protomegastrophia profunda (Hall)
*50. Rhynchonellata: Atrypida: Atrypidae: Atrypa sp.
51. Rhynchonellata: Atrypida: Atrypidae: Plectatrypa sp.
52. Rhynchonellata: Atrypida: Atrypidae: Reticulatrypa sp.
53. Rhynchonellata: Atrypida: Atrypinidae: Atrypina magnaventra Grubbs
54. Rhynchonellata: Athyridida: Nucleospiridae: Nucleospira sp.
55. Rhynchonellata: Athyridida: Meristellidae: Whitfieldella sp.
56. Rhynchonellata: Athyridida: Meristellidae:  Meristina sp.
57. Rhynchonellata: Orthida: Platystrophiidae: Platystrophia sp.
58. Rhynchonellata: Orthida: Rhipidomellidae: Dalejina sp.
59. Rhynchonellata: Orthida: Dicoelosiidae: Dicoelosia biloba (Linnaeus)
60. Rhynchonellata: Orthida: Hesperorthidae: Dolerorthis sp.
61. Rhynchonellata: Orthida: Hesperorthidae: Ptychopleurella sp.
62. Rhynchonellata: Orthida: Dalmanellidae Isorthis clivosa Walmsley
63. Rhynchonellata: Orthida: Dalmanellidae  Resserella canalis (Sowerby)
64. Rhynchonellata: Protorthida: Skenidiidae: Skenidioides sp.
65. Rhynchonellata: Rhynchonellida: Trigonirhynchiidae: Rhynchotreta sp.
66. Rhynchonellata: Rhynchonellida: Hebetoechiidae: Sphaerirhynchia sp.
*67. Rhynchonellata: Rhynchonellida: Rhynchotrematidae: Stegerhynchus sp.
*68. Rhynchonellata: Spiriferida: Cyrtiidae: Eospirifer radiatus (Sowerby)
*69. Rhynchonellata: Spiriferida: Cyrtiidae:  Janius nobilis (Hall)
70. Rhynchonellata: Spiriferida: Cyrtiidae: Macropleura eudora (Hall)
71. Rhynchonellata: Spiriferida: Cyrtiidae: Striispirifer sp.
72. Rhynchonellata: Spiriferida: Cyrtiidae: Cyrtia meta (Hall)
73. Rhynchonellata: Spiriferida: Delthyrididae: Howellella sp.
74. Rhynchonellata: Pentamerida: Parastophinella multiplicata (Hall & Clarke)
75. Rhynchonellata: Pentamerida: Parastrophinidae: Anastrophia internascens Hall
76. Rhynchonellata: Pentamerida: Clorindidae: Antirhynchonella ventricosa (Hall)
*77. Rhynchonellata: Pentamerida: Pentameridae: Apopentamerus racinensis Boucot & Johnson
78. Rhynchonellata: Pentamerida: Pentameridae: Capelliniella mira (Hall & Clarke)
79. Rhynchonellata: Pentamerida: Subrianidae: Conchidium multicostatum Hall



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