Taxonomic validity of Petalodus ohioensis (Chondrichthyes, Petalodontidae) based on a cast of the lost holotype GEOLOGY OF THE INTERMOUNTAIN WEST an open-access journal of the Utah Geological Association ISSN 2380-7601 Volume 6 2019 © 2019 Utah Geological Association. All rights reserved. For permission to copy and distribute, see the following page or visit the UGA website at www.utahgeology.org for information. Email inquiries to GIW@utahgeology.org. TAXONOMIC VALIDITY OF PETALODUS OHIOENSIS (CHONDRICHTHYES, PETALODONTIDAE) BASED ON A CAST OF THE LOST HOLOTYPE Kenneth Carpenter and Wayne M. Itano GEOLOGY OF THE INTERMOUNTAIN WEST an open-access journal of the Utah Geological Association ISSN 2380-7601 Production Cover Design and Desktop Publishing Douglas A. Sprinkel Cover Two views of a cast of the long-lost holotype of Petalodus ohioensis Safford, 1853 and hypo- thetic restoration of the shark. The cast resolves the long historical debate about the validity of this ancient shark tooth species. i Become a member of the UGA to help support the work of the Association and receive notices for monthly meetings, annual field conferences, and new publi- cations. Annual membership is $20 and annual student membership is only $5. Visit the UGA website at www.utahgeology.org for information and membership application. The UGA board is elected annually by a voting process through UGA members. However, the UGA is a volunteer-driven organization, and we welcome your voluntary service. If you would like to participate please contact the current president or committee member corresponding with the area in which you would like to volunteer. Utah Geological Association formed in 1970 from a merger of the Utah Geological Society, founded in 1946, and the Intermountain Association of Geologists, founded in 1949. Affiliated with the American Association of Petroleum Geologists. 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Sprinkel Utah Geological Survey 801.391.1977 GIW@utahgeology.org Bart J. Kowallis Brigham Young University 801.422.2467 bkowallis@gmail.com Thomas C. Chidsey, Jr. Utah Geological Survey 801.537.3364 tomchidsey@utah.gov Steven Schamel GeoX Consulting, Inc. 801.583-1146 geox-slc@comcast.net Society of Vertebrate Paleontology Editors Kelli C. Trujillo — University of Wyoming John Foster — Utah Field House of Natural History State Park Museum Cary Woodruff — University of Toronto Octavio Mateus — Universidade Nova de Lisboa GEOLOGY OF THE INTERMOUNTAIN WEST an open-access journal of the Utah Geological Association Volume 6 2019 55 ABSTRACT Only a crude line drawing of the holotype tooth of the shark Petalodus ohioensis Safford, 1853 has ever been published, and the location of that specimen has long been unknown. The discovery of a cast of the holotype in the collections of the Yale Peabody Museum of Natural History demonstrates that P. alleghaniensis Leidy, 1856, is a junior subjective synonym of P. ohioensis, thus resolving a long-standing dispute. Taxonomic Validity of Petalodus ohioensis (Chondrichthyes, Petalodontidae) Based on a Cast of the Lost Holotype Kenneth Carpenter1 and Wayne M. Itano2 1Prehistoric Museum, Utah State University Eastern, 155 Main St., Price, UT 84501; and Museum of Natural History, University of Colorado, Boulder, CO 80309; Ken.Carpenter@usu.edu 2Museum of Natural History, University of Colorado, Boulder, CO 80309; wayne.itano@aya.yale.edu Citation for this article. Carpenter, K., and Itano, W.M., 2019, Taxonomic validity of Petalodus ohioensis (Chondrichthyes, Petalodontidae) based on a cast of the lost holotype: Geology of the Intermountain West, v. 6, p. 55–60. © 2019 Utah Geological Association. All rights reserved. For permission to use, copy, or distribute see the preceeding page or the UGA website, www.utahgeology.org, for information. Email inquiries to GIW@utahgeology.org. INTRODUCTION The discovery of teeth from the Late Paleozoic shark, Petalodus, from the near the top of the Permian “lower Cutler beds” of the Cutler Group in southeast- ern Utah, led to a brief description and illustration of many important holotypes and referred specimens in order to determine the taxon to which the lower Cutler teeth belonged (Carpenter and Ottinger, 2018). Several important and key specimens were illustrated by pho- tographs for the first time, including the holotypes of P. hastingsii Owen, 1840, P. acuminatus (Agassiz, 1838), P. rhombus (M’Coy, 1854), and P. alleghaniensis Leidy, 1856. One crucial specimen that could not be located for photographic inclusion was the holotype of P. ohio- ensis Safford, 1853 from the Cambridge Limestone of the Conemaugh Formation in Ohio. Specimens have been referred to this species (e.g., Hay, 1895; Lucas and others, 2011; Carpenter and Ottinger, 2018) based on the crude illustration by Safford (1853) (see figures 1A and 1B). This specimen is crucial for resolving the is- sue of whether P. alleghaniensis (figures 1E and 1F) is a separate taxon from P. ohioensis or a junior subjec- tive synonym of P. ohioensis (e.g., Hay, 1895; Zidek and Kietzke, 1993, 1996; Brusatte, 2007; Ivanov and others, 2009; Ginter and others, 2010; Carpenter and Ottinger, 2018). The discovery of a cast (figures 1C and 1D) of the holotype of P. ohioensis finally resolves the issue. INSTITUTIONAL ABBREVIATIONS ANSP–Academy of Natural Sciences of Philadel- phia, Philadelphia, Pennsylvania; MCZ–Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts; NHMUK–Natural History Museum, United Kingdom, London, England; USNM–United States National Museum (National Museum of Natural History), Washington, D.C.; YPM–Yale Peabody Muse- um of Natural History, New Haven, Connecticut. HISTORY OF THE PROBLEM The morphological tooth genus Petalodus was named by Richard Owen (1840–1845), as Petalodus 56 Taxonomic Validity of Petalodus ohioensis (Chondrichthyes, Petalodontidae) Based on a Cast of the Lost Holotype Carpenter, K., and Itano, W.M. Geology of the Intermountain West 2019 Volume 6 hastingsii, for a fragment of a tooth from the Ticknall Limestone (upper Viséan = upper Middle Mississippi- an) in South Derbyshire, England (the fragment, figures 1G and 1H, is not diagnostic and a proposal has been submitted by us to the International Commission on Zoological Nomenclature to make the more complete NHMUK PV P.75414, figures 1I and 1J, from the same locality, the neotype for the taxon; Carpenter and Itano, 2018). In 1850, Professor James Safford, geologist at Cum- berland University in Lebanon, Tennessee, collected a tooth having a triangular crown from the Cambridge Limestone of the Conemaugh Formation (middle to upper Missourian = lower Upper Pennsylvanian) near the town of Cambridge in Guernsey County, southeast- ern Ohio. Fortuitously for him, Louis Agassiz had emi- grated to the United States in 1847 and was at the 1851 American Association for the Advancement of Science meeting, where Safford showed him the tooth. Be- fore emigrating, Agassiz had published his multi-year (1833–1845a, 1833–1845b), ten volume “Recherches sur les Poissons Fossiles” [“Research on Fossil Fish”] and was quite familiar with the kind of tooth Safford showed him. Agassiz, who was then at Harvard Univer- sity, “pronounced it at once a new species of Getalodus” (Safford, 1853, p. 142). Shortly thereafter, Safford was successful in removing the specimen from the matrix and published a brief paragraph (Safford, 1853) nam- ing the taxon Getalodus ohioensis and provided two views of the tooth (reproduced here as figures 1A and 1B), which Hay (1895) reports were woodcuts. Safford’s publication was overlooked in subsequent descriptions Figure 1. Petalodus ohioensis (as Getalodus ohioensis) as illustrated by Safford (1853, p. 142) in (A) labial and (B) lingual views, compared to a cast (YPM 2861) purported to be of the specimen in (C) labial and (D) lingual views. Holotype of Pet- alodus alleghaniensis (ANSP 14541) in (E) labial and (F) lingual views. Holotype of Petalodus hastingsii (NHMUK PV P.613) in (G) labial and (H) lingual views. Proposed neotype (NHMUK PV P.75414, formerly part of P.5342; Carpenter and Itano, 2018) in (I) labial and (J) lingual views. The origin of the green dot on specimen H is uncertain but may have been the code used by Woodward (1889) or Owen (1840–1845) to denote it was a holotype. The red dot on specimen J is a blob of wax used by Woodward (1889) to denote that he included the specimen in his catalog of fossil fishes. The blue star on specimen E is the old symbol used to denote a holotype. Scale in mm. 57 Taxonomic Validity of Petalodus ohioensis (Chondrichthyes, Petalodontidae) Based on a Cast of the Lost Holotype Carpenter, K., and Itano, W.M. Geology of the Intermountain West 2019 Volume 6 of specimens of Petalodus from the United States (Leidy, 1855, 1856, 1873; Newberry and Worthen, 1866; St. John, 1870; Newberry, 1875), until its “rediscovery” by Hay (1895). Hay (1895, 1902) commented that the ge- neric name “Getalodus” was a typographical error for Petalodus, either due to misinterpretation of Safford’s handwritten manuscript by the typesetter, or Safford’s misunderstanding of Louis Agassiz’ heavy Swiss French accent during their conversations. Two years after Safford named Petalodus ohioensis, Leidy (1855) named Sicarius extinctus for a tooth that was loaned to him, and noted, that it resembled a pan- golin scale. Leidy (1855) thought it was fish but did not rule out reptile. The specimen was found in the Glen- shaw Formation (Missourian = lower Upper Pennsyl- vanian) at Bens Creek Station in what is now the Al- legheny Portage Railroad National Historic Site near Cresson, Pennsylvania (Koch and Santucci, 2004). The following year, Leidy (1856) renamed the tooth Petal- odus alleghaniensis (note original spelling, sometimes subsequently misspelled allegheniensis [Goto and Oku- ra, 2004; Monson, 2010]), described it in detail and il- lustrated it. The specimen is currently in the collections of The Academy of Natural Sciences of Philadelphia (ANSP 14541, figures 1E and 1F). The name change from Sicarius to Petalodus is understandable once Leidy learned what Petalodus teeth were like. What is not clear is why he also changed the species name; no reason was given. Hay (1895) raised the possibility that P. ohioensis had priority over P. alleghaniensis, as well as P. destruc- tor named by Newberry and Worthen (1866) and his own P. securiger. However, because he did not think Saf- ford’s drawings were wholly accurate and because the whereabouts of Safford’s specimen was unknown for comparison, he only synonymized P. destructor with P. ohioensis based on similarities of the crowns and sizes. Eastman (1896) considered P. ohioensis a nomen dubi- um because Safford’s description was insufficient and the drawing probably inaccurate. This position, howev- er, has not been followed (e.g., Hay, 1902; Hansen, 1985, 1996; Dalla Vecchia, 1988; Zidek and Kietzke, 1993; Brusatte, 2007; Ginter and others, 2010; Carpenter and Ottinger, 2018). A FINAL RESOLUTION Recently, one of us (WMI) discovered a cast identi- fied as of the holotype P. ohioensis in the collections of the YPM (YPM 2861) (figures 1C and 1D). Notes as- sociated with the cast refer to it as the “plastotype” and that it was obtained from the MCZ. The cast was cata- logued at the YPM on September 18, 1930 (Don Brink- man, YPM, written communication, June 15, 2018). However, there are no records at the MCZ of the cast or original specimen from which the cast was made (Jes- sica Cundiff, MCZ, written communication, June 15, 2018). This absence may explain why Eastman (1896), who was at the MCZ at the time of his article, made no mention of the specimen. Although the quality of the cast is low, it does show that the tooth was more than just the crown. Of the crown, the cingulum of imbricated ridges at the base of the crown on both the labial and lingual sides as shown by Safford (1853) are not very distinct. Nor does the cast display the striated occlusal margin as shown by Saf- ford. Nevertheless, the cast does confirm that the spec- imen has the distinctive crown of Petalodus, which is triangular, vertically short, broad-based, labio-lingually compressed, convex labially, and concave lingually. The root is complete and has the characteristic tongue-shape of Petalodus. In addition, it is D-shaped in horizontal cross section, with the lingual side flat. Measurements are given in table 1. Although larger, the tooth strong- ly resembles that of P. alleghaniensis in crown profile and presence of a notch in the lower corner of the root, which may help determine tooth position. We can find no reason for recognizing two taxa and here formally synonymize P. alleghaniensis Leidy, 1856 with P. ohioen- sis Safford, 1853 as first suggested by Hay (1895). SYSTEMATIC PALEONTOLOGY Class Chondrichthyes Huxley, 1880 Order Petalodontiformes Patterson, 1965 Petalodontida Zangerl, 1981 Family Petalodontidae Newberry and Worthen, 1866 Genus Petalodus Owen, 1840 58 Taxonomic Validity of Petalodus ohioensis (Chondrichthyes, Petalodontidae) Based on a Cast of the Lost Holotype Carpenter, K., and Itano, W.M. Geology of the Intermountain West 2019 Volume 6 Synonymies Chomatodus Agassiz, 1838 (in part) Getalodus Safford, 1853 err typo Ctenopetalus Davis, 1881 Sicarius Leidy, 1855 Species Petalodus ohioensis Safford, 1853 Synonymies Sicarius extinctus Leidy, 1855 Petalodus alleghaniensis Leidy, 1856 Petalodus allegheniensis Leidy, 1856 err typo Petalodus destructor Newberry and Worthen, 1866 Petalodus securiger Hay, 1895 CONCLUSIONS It has been 165 years since James Safford named and illustrated Petalodus ohioensis for a tooth from the Up- per Pennsylvanian of Ohio. The taxonomic validity of the name has been problematic because the holotype is missing, and the original description and illustrations are insufficient. The discovery of a cast purported to be of the holotype has resolved a decades-long debate as to the validity of the taxon and the seniority of the species name over that of P. alleghaniensis Leidy, 1856. Pend- ing discovery of the original specimen of P. ohioensis, the cast (YPM 2861) may act as a representative of that specimen, but the cast itself as a three-dimensional il- lustration of the specimen, is not the holotype (ICZN Art. 72.5.3 with 73.1.4). The term “plastotype,” which is written on a label with the cast, is a term not regulated by the International Code of Zoological Nomenclature (ICZN) and is not used here. This cast also negates the need for a neotype (as defined by ICZN Article 75) of P. ohioensis, which fortunately has never been published, despite appearing on a label accompanying a cast at the NHMUK in London. That label accompanies a cast, NHMUK PV P.58463, which is a cast of USNM PAL 244454. However, ICZN Article 9 is clear that a notation written on a label is not a valid designation. Further- more, the discovery of the cast of the holotype would set aside the neotype designation (ICZN Article 75.8). ACKNOWLEDGMENTS Don Brinkman (Yale Peabody Museum of Natural History, New Haven, Connecticut) gave W. Itano access to collections, which led to the discovery of the cast YPM 2861 and provided collection data. Jessica Cundiff (Museum of Comparative Zoology, Harvard Universi- ty, Cambridge, Massachusetts) searched for the origi- nal of Petalodus ohioensis and provided information on the Petalodus specimens under her care. Ned Gilmore (Academy of Natural Sciences, Drexel University, Phila- delphia, Pennsylvania) provided images of the holotype of Petalodus alleghaniensis. Emma Bernard (Natural History Museum, London, England) provided W. Ita- no access to collections and assigned a new specimen number for a specimen selected as the neotype of Petal- odus hastingsii. We thank Mike Hansen (retired, Ohio Geological Survey, The Ohio State University, Colum- bus, Ohio), Jim Kirkland (Utah Geological Survey), and Spencer Lucas (New Mexico Museum of Natural Histo- ry and Science) for their reviews. Taxon (catalog number) Crown side Maximum tooth height (mm) Maximum crown width (mm) Maximum mid-crown height to top of cingulum (mm) Maximum cingulum mid- height (mm) P. ohioensis (YPM 2861) (H) Labial 39.3 35.3 15.5 3.4 Lingual 25.8 3.1 P. alleghaniensis (ANSP 14541) (H) Labial 34.5 (35.3 e) 30.2 (30.6 e) 15.6 3.7 Lingual 20 5.5 P. acuminatus (MHNN-FOS 171) (H) Lingual NA 34.6 (e) 16.6 3.3 Table 1. Measurements for specimens of Petalodus used in this study. Abbreviations: (e) – estimate; (H) – holotype; mm – millimeter; NA – not available. 59 Taxonomic Validity of Petalodus ohioensis (Chondrichthyes, Petalodontidae) Based on a Cast of the Lost Holotype Carpenter, K., and Itano, W.M. 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