Mapes and Doguzhaeva—New Pennsylvanian coleoids from Nebraska and Iowa
from 1.8 to 3.1mm; the large range in diameter is probably the result of variations in the orientation of the structures and amount of septal deposits around the septal necks. All of the clusters have pieces of phragmocone, and septal spacing ranges from 0.6 to 3.3mm; most have a septal spacing of 1.5 to 2.5mm. All of the specimens appear to have some shell fragments that were a part of the body chamber. The longest body chamber segment is on specimen UNSM 16570 with a length of 55mm. Specimen UNSM 16569 (Fig. 3.1–3.6) was selected as
being typical of the debris clusters. The fossilized material forms an irregular-shaped blob that was partly controlled by how it was originally deposited and how the bedding planes split during the collecting process. All of the shell debris, which was probably somewhat three-dimensional despite being broken into fragments when deposited on the sea floor, has numerous fractures and deformation due to flattening produced by lithostatic compaction. Some shell pieces show ‘wrinkling” and folding of the shell fragments suggesting that there were significant amounts of organic material in the shell ultrastruc- ture. Only two poorly preserved arm hooks are present in the cluster, and they are scattered in the unidentifiable, finely macerated debris associated with the phragmocone and body chamber pieces. Septal spacing on phragmocone segments ranges from 1.2 to 2.3mm.
Occurrence.—All of the coleoid debris clusters were recovered by splitting blocks of Stark Shale (Pennsylvanian, Missourian = Kasimovian) at the Old Public Works (WPA) Quarry near Bellevue, Nebraska. No other information is available. The degree of completeness of the clusters was controlled by the shape of the shale block in the waste pile in the quarry and in the “luck of the split” when processing any particular shale block.
Discussion.—These clusters are considered to be coleoids based on the combined presence of ink, arm hooks, septal spacing, and similarity in preservation. Based on the presence of the finely macerated material and the breakage associated with the coloeid shells, these clusters are interpreted as ejectoid masses or as coprolites from predators. It is unlikely that this shell breakage occurred after the coleoid was deposited on the sea floor because the sea floor is thought to have been anoxic based on the lack of benthic fauna and the presence of bedded and nodular phosphate in the shale. Based on described taxa from the Carboniferous, these coleoids are most closely related to Donovaniconus from the Wewoka Formation (Pennsylvanian, Desmoinesian = Moscovian) in Oklahoma (Doguzhaeva et al., 2003) or to a closely related taxon.
Acknowledgments
All of the specimens described herein were collected by W.D. White, J.P. Pope, and R. Pabian from limestone quarries in the
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vicinity of Omaha, Nebraska and across the border to the east in west central Iowa. We thank them for their tireless efforts in developing these irreplaceable Stark collections. Additionally, RHM is very grateful to K. Tanabe and his students for helpful discussions of these specimens and fossil ink, and to K. Sasaki, all at the University of Tokyo, Tokyo, Japan for aiding in obtaining the modern coleoids and their ink. Some of the figure photographs were produced by J. Sattler, and P. Sattler used her skills to assemble the figures. We are very grateful for their assistance and skills.
References
Bather, F.A., 1888, Shell-growth in Cephalopoda (Siphonopoda): Annals and Magazine of Natural History, v. 6, p. 298–310.
Doguzhaeva, L.A., 1996, Two Early Cretaceous spirulid coleoids of the north- western Caucasus: their shell ultrastructure and evolutionary implication: Palaeontology, v. 39, p. 681–707.
Doguzhaeva, L.A., 2002, Adolescent Bactritoid, Orthoceroid, Ammonoid and Coleoid Shells from the Upper Carboniferous and Lower Permian of the southern Urals, in Summesberger, H., Histon, K., and Daurer, A., eds., Coleoid Cephalopods Through Time: Abhandlungen der Geologischen Bundesanstalt, 57, p. 9–55.
Doguzhaeva, L.A., and Mapes, R.H., 2015, Arm hooks and structural features in the Early Permian Glochinomorpha Gordon 1971, indictive of its coleoid affiliation: Lethaia, v. 48, p. 100–114.
Doguzhaeva, L.A., and Mapes, R.H., in press, A new genus and a new family of the Late Paleozoic coleoids (Cephalopoda, Coleoidea: Donovaniconida) from Oklahoma, USA, showing soft tissue preservation: Journal of Paleontology.
Doguzhaeva, L.A., and Mutvei, H., 2003, Gladius composition and ultra- structure in extinct squid-like coleoids: Loliogosepia, Trachyteuthis and Teudopsis: Revue de Paléobiologie, v. 22, p. 877–894.
Doguzhaeva, L.A., Mapes, R.H., and Mutvei, H., 1999, A Pennsylvanian spirulid coleoid from the Southern Mid-continent (USA), in Oloriz, F., and Rodriguez-Tovar, F.J., eds., Advancing Research on Living and Fossil Cephalopods: New York, Boston, Dordrecht, London, Moscow, Klumer Academic/Plenum Publishers, p. 47–57.
Doguzhaeva, L.A., Mapes, R.H., and Mutvei, H., 2002a, Shell morphology and ultrastructure of the Early Carboniferous coleoid Hematites Flower & Gordon, 1959 (Hematitida ord. nov.) from Midcontinent (USA), in Summesberger, H., Histon, K., and Daurer, A., eds., Cephalopods—Past and Present: Abhandlungen der Geologischen Bundesanstalt, Band 57: Geologische Bundesanstalt, Wien, p. 299–320.
Doguzhaeva, L.A., Mapes, R.H., Mutvei, H., and Pabian, R.K., 2002b, The Pennsylvanian phragmocone-bearing orthoconic coleoids with ink sacs: their environment and mode of life, in Brock, G.A., and Talent, J.A., eds., Abstracts, First International Palaeontology Congress, 6–10 July 2002, Macquarie University: NSW Australia, Geological Society of Australia, v. 68, p. 200.
Doguzhaeva, L.A., Mapes, R.H., and Mutvei, H., 2003, The shell and ink sac morphology and ultrastructure of the Late Pennsylvanian cephalopod Donovaniconus and its phylogenetic significance: Berliner Paleo- biologische Abhandlungen, v. 3, p. 61–78.
Doguzhaeva, L.A., Mapes, R.H., and Mutvei, H., 2004, Occurrence of ink in Paleozoic and Mesozoic coleoids (Cephalopoda): Mitteilungen aus dem Geologisch-Paläontologischen Institut der Universität Hamburg, v. 88, p. 145–156.
Doguzhaeva, L.A., Mapes, R.H., and Dunca, E., 2006,APennsylvanian adolescent cephalopod from Texas (USA), with a short rostrum and a long body chamber: Acta Universitatis Carolinae—Geologica, v. 49, p. 55–68.
Doguzhaeva, L.A., Mapes, R.H., and Mutvei, H., 2007, A Pennsylvanian coleoid cephalopod from the Mazon Creek Lagerstätte (USA), with a radula, arm hooks, mantle tissues and ink, in Landman, N.H., Davis, R.A., Mapes, R.H., and Manger, W.L., eds., Cephalopods—Present
Figure 4. (1–4) Unidentified coleoid specimen UMSN 16569B. (1) Overall view of the disarticulated and fragmented pieces of the phragmocone and body chamber on a single bedding plane in the shale; (2) enlargement of a section of the phragmocone showing the septal spacing and the size of the mural part of the septal attachment to the inner shell wall; (3) enlargement of a partly complete arm hook (ah) surrounded by macerated debris and fragmented shell pieces; (4) impression of a phragmocone segment (lower) and macerated debris (upper); (5–7) Unidentified coleoid specimen UMSN 16566A; (5) shell debris with unidentified finely macerated material preserved as an irregular blob on a single bedding plane; (6) enlargement showing two arm hooks (ah) in macerated debris; (7) enlargement of a segment of the phragmocone showing septal spacing (s). Scale bar is 3mm in Figure 4.3 and 1mm in Figure 4.6; the remaining scales are 5mm.
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