If you need an accessible version of this item please contact JSTOR User Support

Morphology, Systematics, and Evolution of Middle Devonian Ambocoeliidae (Brachiopoda), Western New York

Daniel Goldman and Charles E. Mitchell
Journal of Paleontology
Vol. 64, No. 1 (Jan., 1990), pp. 79-99
Published by: Paleontological Society
Stable URL: http://www.jstor.org/stable/1305546
Page Count: 21
  • Download PDF
  • Cite this Item

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If you need an accessible version of this item please contact JSTOR User Support
Morphology, Systematics, and Evolution of Middle Devonian Ambocoeliidae (Brachiopoda), Western New York
Preview not available

Abstract

The internal morphology of ambocoeliid brachiopods from the Middle Devonian Hamilton Group of western New York indicates a need for several taxonomic revisions. "Ambocoelia" praeumbona is transferred to Emanuella. "Ambocoelia" spinosa and "A." nana represent Crurispina n. gen. Specimens of species belonging to Crurispina have moderately well developed crural plates, and, accordingly, they are assigned to the subfamily Rhynchospiriferinae. Crural plates are small and obscure but clearly present in Ambocoelia umbonata, the type species of Ambocoelia. Thus, the diagnosis of the subfamily Ambocoeliinae is emended to include species with tiny crural plates. Ambocoeliid specimens from the Levanna Shale Member of the Skaneateles Formation, formerly referred to Echinocoelia, reveal several elaborate features in the pedicle valve, including an apical plate and a hollow tube supported by a median septum. These specimens represent a new genus and species, Mucroclipeus eliei. The homeomorphy found in the shape and size of these ambocoeliids may be the result of paedomorphosis. Additionally, their pattern of occurrence and minute size suggest that they attained their paedomorphic state through progenesis. The taxa Ambocoelia tuberculata n. sp., Crurispina n. gen., and Mucroclipeus eliei n. gen. and sp. are established.

Page Thumbnails

  • Thumbnail: Page 
79
    79
  • Thumbnail: Page 
80
    80
  • Thumbnail: Page 
81
    81
  • Thumbnail: Page 
82
    82
  • Thumbnail: Page 
83
    83
  • Thumbnail: Page 
84
    84
  • Thumbnail: Page 
85
    85
  • Thumbnail: Page 
86
    86
  • Thumbnail: Page 
87
    87
  • Thumbnail: Page 
88
    88
  • Thumbnail: Page 
89
    89
  • Thumbnail: Page 
90
    90
  • Thumbnail: Page 
91
    91
  • Thumbnail: Page 
92
    92
  • Thumbnail: Page 
93
    93
  • Thumbnail: Page 
94
    94
  • Thumbnail: Page 
95
    95
  • Thumbnail: Page 
96
    96
  • Thumbnail: Page 
97
    97
  • Thumbnail: Page 
98
    98
  • Thumbnail: Page 
99
    99