PETALOUS OHIOENSIS, THE MOST COMMON SHARK TOOTH FOUND AT MCCOY, COLORADO, AND THE SEARCH FOR ITS LOST HOLOTYPE. Part 2: Recent history of Petalodus ohioensis and the discovery of casts of its holotype

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MARCH 2020 | TRILOBITE TAL ES 23
PETALOUS OHIOENSIS, THE MOST COMMON SHARK TOOTH
FOUND AT MCCOY, COLORADO, AND THE SEARCH FOR ITS
LOST HOLOTYPE
by Wayne Itano
Part 2: Recent history of Petalodus ohioensis and the discovery of casts of its holotype
Introduction
In Part 1 of this series, in the February 2020 Trilobite Tales, I related the complex history of our knowledge
of the Pennsylvanian/Permian shark species Petalodus ohioensis, beginning with its published description
by James Merrill Safford (1853). That publication seems to have gone unnoticed by all other researchers
in the field for over 40 years. During that period, various “new” species of Petalodus were named, such
as P. alleghaniensis and P. destructor, which probably are equivalent to P. ohioensis. If so, the name
Petalodus ohioensis ought to have priority, since it was the first to be named.
Even after Safford’s article was noticed, the name Petalodus alleghaniensis was often used in preference to
Petalodus ohioensis, perhaps because Safford published only crude line drawings of the tooth and
because the location of Safford’s holotype (the specimen upon which his description was based) was
not known to the scientific community.
A change in the status of Petalodus ohioensis seems to have occurred due to the influence of Michael
Hansen, who published a comprehensive review of the petalodontiform chondrichthyans (the group of
sharks that includes Petalodus) (Hansen, 1985). Hansen used the name Petalodus ohioensis in preference
to Petalodus alleghaniensis. He also stated that P. ohioensis is the dominant Pennsylvanian and Early
Permian species. From that time, the use of the name Petalodus ohioensis seems to have grown in
popularity. Still, there was a nagging question as to the whereabouts of the holotype.
History of Petalodus at McCoy, Colorado
Many WIPS members have collected fossils in the
Minturn Formation, of Pennsylvanian age (about 300
million years old), in the vicinity of McCoy, Eagle
County, Colorado. Marine invertebrates are abundant,
and shark teeth, mostly of Petalodus, are found
occasionally. To the best of my knowledge, all Petalodus
teeth from McCoy belong to Petalodus ohioensis.
Professor Junius Henderson, of the University of Colorado,
collected Petalodus teeth from McCoy in the early
1900s. I have seen these in the collections of the
University of Colorado Museum of Natural History. I
have also observed two Petalodus teeth from McCoy in
the collections of the Geology Museum of the Colorado
School of Mines (Fig. 1). According to the labels, these
teeth were collected in 1927 by geologists Higgins and Breckenridge, of the Texas Production
Company. Calvin Stevens, in his master’s thesis on the stratigraphy and paleontology of McCoy
(Stevens, 1958), noted the presence of Petalodus teeth, which he identified as Petalodus destructor. In
the 1980s, Professor Martin Lockley and Dr. Karen Houck of the University of Colorado at Denver
collected many shark teeth at McCoy, including those of Petalodus ohioensis (Houck & Lockley, 1986;
Lockley, 1984).
Figure 1. A, B. Petalodus ohioensis teeth from McCoy,
Colorado, collected in 1927 and reposited in the CSM Geology
Museum. Small divisions on scales are 1 mm.

24 TRILOBITE TALES | MARCH 2020
My contribution: Locating casts of the
holotype at the Yale Peabody Museum
In May 2013, I was in New Haven for a
reunion of my Yale college class. I took
advantage of the trip to arrange a visit to the
collections of the Yale Peabody Museum of
Natural History (YPM). Before I went, I
checked the online specimen catalog and
made note of specimens that might be
interesting. One of these was YPM VP 2861,
said to be a cast of the holotype of Petalodus
ohioensis. At that time, I did not know that
others, including Hansen, had tried and failed
to locate the holotype. Figure 2 is a
photograph of the label and two casts of the
same tooth, from the current online catalog of
the Yale Peabody Museum. That photograph
was not available in 2013. Figure 3 is an old
label associated with the casts. It states that
the casts were supplied by the Museum of
Comparative Zoology (MCZ) at Harvard
University. The term “plastotype” on the label
refers to a cast made of a type specimen. The
origin of the word is from “plaster” and not
“plastic” as I had initially thought. I
photographed the casts and didn’t think about
them for five years.
In June 2018, I noticed a new publication by
Dr. Ken Carpenter, of the Prehistoric Museum
in Price, Utah, and the Natural History
Museum of the University of Colorado, and
Lin Ottinger. They reported some Permian
shark teeth from Utah, including the first Petalodus ohioensis to be described from that state (Carpenter
& Ottinger, 2018). They stated that they had been unable to locate the holotype of P. ohioensis. I emailed
Ken with photos of the plastotypes. He proposed that we write a short paper reporting their existence.
It happened that I was scheduled to be at the Natural History Museum in London (NHMUK) the
following week and could view their Petalodus specimens. My daughter Nicole lives in London, so I
visit frequently. Ken asked me to search for a candidate neotype for Petalodus hastingsii. A neotype is a
substitute holotype that might be needed in case the holotype is believed to be irretrievably lost or is
otherwise unsuitable. The holotype of P. hastingsii is incomplete and lacks important diagnostic features,
so the species might need a neotype. I did come up with a candidate neotype, which is the subject of
another paper (Carpenter & Itano, 2018). We enquired at the MCZ and found that the collections
manager was unable to locate either the holotype or casts of it or indeed any record of their ever having
been there. This made the existence of the casts at the YPM even more important, and Ken and I decided
to write a paper on the subject.
Figure 4 compares Safford’s figures (Figs. 4A,B) to my photographs of the cast (Figs. 4C,D). It is
unfortunate that Safford did not illustrate the root, since that would have helped to verify the identity,
but otherwise, the drawings and photographs compare very closely. There is even a nick in the edge
that is in the same spot (red arrows).
Figure 2. Two casts of the holotype of Petalodus ohioensisSafford, 1853.
Specimen number YPM PV 2861. Photo by Division of Vertebrate
Paleontology, Yale Peabody Museum, 2016.
Figure 3. A label associated with the YPM casts of the holotype of
Petalodus ohioensis.

Another surprise: A neotype of Petalodus
ohioensis (but not a valid one)
During my visit to the NHMUK, I was surprised to
find a cast supposedly of the neotype of Petalodus
ohioensis (Figs. 5 A,B). Figure 6 shows the label. I
had not been aware that a neotype was in existence.
According to the register book, the cast had been
donated by Michael Hansen in 1976, and the
original was in the USNM. I tracked down the
original at the USNM website (Fig. 7) and found
that it had specimen number USNM PAL 244454
and had been identified by Michael Hansen.
Apparently, Hansen, during his studies on
Petalodus, had been unable to locate the holotype
of Petalodus ohioensis and decided that it was
necessary to designate a specimen as the neotype.
There are various requirements set by the
International Commission on Zoological
Nomenclature (the organization that set the rules
of the naming of taxa) for a neotype to be valid. It
is not enough simply to write it on a label. Among
these requirements is that the designation be published.
This was never done, and now that the casts have
been located, there is no need for a neotype.
Conclusion
Ken Carpenter and I wrote a paper (Carpenter &
Itano, 2019) announcing the location of the casts
of the holotype of P. ohioensis at the Yale Peabody
Museum. Existence of the casts ensures that the
species name Petalodus ohioensis is valid and that
various later-named species, like Petalodus
alleghaniensis, are junior synonyms of Petalodus
ohioensis.
Figure 4. Drawings of (A) Labial (outer) face and (B) lingual (inner)
face of the holotype of P
. ohioensis, from Safford (1853).
Photographs of (C) Labial and (D) lingual face of a cast of the
holotype at the Yale Peabody Museum. Specimen number YPM PV
2861. Small divisions on scale are 1 mm.
Figure 5. (middle right) Cast of the supposed
neotype of Petalodus ohioensis. (A) Labial face;
(B) lingual face. Specimen number NHMUK PV
P58463. 1 cm scale.
Figure 6. (bottom right) Label of the cast of the
supposed neotype of Petalodus ohioensis in the
collections of the NHMUK.
Figure 7. (right) Lingual face of the supposed
neotype of Petalodus ohioensis at the USNM
(Smithsonian). This view corresponds to that of
Fig. 5B of the NHMUK cast. Specimen number
USNM PAL 244454. Cambridge Limestone,
Guernsey County, Ohio. Photo copyright ©
Smithsonian Institution, all rights reserved.
MARCH 2020 | TRILOBITE TAL ES 25

26 TRILOBITE TALES |MARCH 2020
Acknowledgments
I thank Ken Carpenter for information on Petalodus and the International Code of Zoological
Nomenclature. I thank Dennis Gertenbach and Beth Simmons for access to the CSM collections, Derek
Briggs and Dan Brinkman for access to the YPM collections, and Emma Bernard for access to the
NHMUK collections.
Abbreviations: WIPS: Western Interior Paleontological Society, Denver, CO; CSM: Colorado School of Mines, Golden, CO;
MCZ: Museum of Comparative Zoology, Harvard University, Cambridge, MA; NHMUK: Natural History Museum, London;
YPM: Yale Peabody Museum of Natural History, Yale University, New Haven, CT; USNM: National Museum of Natural
History (Smithsonian), Washington, DC.
References
Carpenter, K., & Itano, W. M. (2018). Case 3779 – Petalodus Owen, 1840 (Chondrichthyes, Petalodontiformes,
Petalodontidae): proposed conservation of usage by designation of a neotype for its type species Petalodus hastingsii.
Bulletin of Zoological Nomenclature, 75(1), 241-246. https://doi.org/10.21805/bzn.v75.a049
Carpenter, K., & Itano, W. M. (2019). Taxonomic validity of Petalodus ohioensis (Chondrichthyes, Petalodontidae) based on a
cast of the lost holotype Geology of the Intermountain West, 6, 55-60. https://doi.org/10.31711/giw.v6.pp55-60
Carpenter, K., & Ottinger, L. (2018). Permo-Pennsylvanian sharks from the lower Cutler beds near Moab, Utah. Geology of
the Intermountain West, 5, 105-116. https://doi.org/10.31711/giw.v5.pp105-116
Hansen, M. C. (1985). Systematic relationships of petalodontiform chondrichthyans. In J. T. Dutro, Jr. & H. W. Pfefferkorn
(Eds.), Neuvième Congrès International de Stratigraphie et de Géologie du Carbonifère, Compte Rendu, Vol. 5 (pp. 523-
541). Carbondale and Edwardsville, IL USA: Southern Illinois University Press.
Houck, K. J., & Lockley, M. G. (1986). A Field Guide to the Pennsylvanian Biofacies of the Minturn Formation, Bond-McCoy
Area, Central Colorado Trough, Geology Department Magazine, Special Issue 2. Denver, CO: University of Colorado at
Denver Geology Department.
Lockley, M. G. (1984). Pennsylvanian predators: a preliminary report on some Carboniferous shark remains from Colorado.
University of Colorado at Denver Geology Department Magazine, 3, 18-22.
Safford, J. M. (1853). Tooth of Getalodus [sic] ohioensis. American Journal of Science and Arts, 16(46), 142.
https://www.biodiversitylibrary.org/item/90339#page/149/mode/1up
Stevens, C. H. (1958). Stratigraphy and paleontology of the McCoy, Colorado area. M.A. thesis, University of Colorado,
Boulder, CO.
Copyright © 2020 Wayne Itano. All rights reserved.
Celebrating our 35th year
In 1984, the Denver Gem and Mineral Council
designated that year’s show theme the “Year of the
Fossil.” The founders of the Western Interior
Paleontological Society, Bryan Cooney and Jordan
Sawdo, were asked to organize a speakers
symposium for the show and provide space for a
meeting to form a new paleontological society.
The result was the formation of the Western
Interior Paleontological Society (WIPS) — a non-
profit organization dedicated to scientific,
educational and charitable activities relating to
paleontology — on January 22, 1985.
Watch for updates in the newsletter, on the web, and at our meetings about how we’ll be
celebrating in 2020!
l Socie
E R S
The W
A N N I V E R S
Wester
ester
n Interior
Paleontological Socie
ty
A R Y
th
2020
A R Y
r
ty
1985

TRILOBITE
TALES
VOLUME 38, NUMBER 3
MARCH 2020
In This Issue
THE REWARDS OF COMMUNITY
OUTREACH . . . . . . . . . . . . . . .16
2020 MEMBERAWARDS . . . . .17
INVERTEBRATEOF THE MONTH:
PYRITIZEDFOSSILS . . . . . . . .21
PETALOUS OHIOENSIS, THE MOST
COMMON SHARKTOOTHAT
MCCOY: PART 2 . . . . . . . . . .23
DEPARTMENTS& COLUMNS
President’s Message . . . . . . . . . 2
Announcements . . . . . . . . . . . . . 3
Member News . . . . . . . . . . . . . .10
Member Profile: John McLeod .11
Field Trips 2020 . . . . . . . . . . . .12
Fossil Outposts: Canon City . . .15
EVENTS
Science Events Calendar . . . . .7
WIPS Events this Month . . . . . 31
FORYOUNGER MEMBERS
PaleoZone . . . . . . . . . . . . . . . . 27
Kids Quarry: Make your own
paper nautiloid! . . . . . . . . . . .28
Stegosaurus, the Colorado State Fossil,
Art © Shannon S. Yeager
THE RANGELY
HADROSAUR
EXCAVATION
Monday, March 2, 2020, 7 p.m.
That Confused Individual Walter: A new dinosaur
discovery unites education and research to foster
local economic growth
Speakers: Liz Johnson & Dan Snyder
Colorado Northwestern Community College
Petroleum Hall, Green Center, Colorado School of Mines
924 16th St., Golden, Colorado
Social time: starts at 6:15 p.m.
Parking is available in all the lots on campus after 5 p.m. as well
as on the street near the Green Center. Be sure to watch for signs
to avoid parking in reserved or maintenance spots.
– More details about the March program on page 4

Trilobite Tales
is the official publication of the
Western Interior
Paleontological
Society (incorporated January 22,
1985). Meetings are held monthly
except for June, July, and August.
Editor: Susan Passmore
Newsletter Committee
Assistant Editor: Gary Raham
Malcolm Bedell, Jr.
MISSION
The purposes of the Society shall be
scientific, educational, and
charitable and shall include field
trips, lectures, seminars and other
educational and science-related
activities; the making available of
information as to exploring for,
identifying, preparing, preserving,
and displaying fossils; encouraging
adherence to responsible codes of
conduct in the exploration for and
collection of fossils; assisting museums
and educational institutions in the
furtherance of their paleontology-
related activities; and cooperating
with government authorities in the
development of laws governing the
collection of fossils and their
preservation for future generations.
MEMBERSHIP
Annual calendar year dues are
$25 for an individual or $30 for a
family/household.
ADVERTISING (Monthly Rates)
full-page $30, half-page $20,
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Info: newsletter@westernpaleo.org
WESTERN INTERIOR
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P.O. BOX 200011
DENVER, COLORADO 80220-0011
WESTERNPALEO.ORG
From the President
I hope the decision to reschedule the February
general meeting was not an issue for anyone. Due
to the snowstorm it made sense to move the
meeting to Monday, February 17th. We were lucky
enough to be able to find another Monday at the
Green Center that our speaker, Natalie Toth, was
also able to make. At this meeting, we awarded
both Generous Service awards and Honorary Life
Member awards to some of your fellow members
deserving of such honors and provided a range of refreshments to
enjoy as well. The Membership Appreciation Committee has been
instrumental in making these awards and refreshments possible and
they have also been a huge proponent of having fossils at general
meetings going forward. Look for a range of fossils on display outside
the auditorium, which will be brought in by members, and please
let someone in leadership know if you would be interested in
bringing something from your collection to display before general
meetings in the future. We have monthly general meetings January
to May and September to December each year, generally on the
first Monday of the month.
Starting in February, the Communications and Outreach Committee
will be hosting the first of several promotional outreach public-facing
events in 2020. The first public outreach will be at the Denver
Gem & Mineral Guild Show, February 28-March 1, and the Ft. Collins
Rockhounds Gem and Mineral Show, March 13-15, where WIPS
will have a display case of “Cretaceous Seaway Fossils” as well as
literature describing the organization, coordinated by Gary Raham
and Susan Passmore. Look for a complete listing and descriptions
of all the 2020 public outreach events planned to date elsewhere in
Trilobite Tales.
It looks like there are two more field trips posted for Como Bluff where
you can find many well-preserved specimens of dinosaurs, mammals,
turtles, crocodilians, and fish from the terrestrial Morrison Formation.
The Como Bluff trips are more about learning the various techniques
used for extracting dinosaur fossils at the quarry rather than a typical
collecting or surveying trip so they are ideal for those who have not
helped excavate at a large quarry before. Check out the Member Login
section of the website for a full list of field trips and sign-up
information for all the field trips planned so far this year. Keep
checking back as new trips get added periodically and they’re all
first-come first-serve.
I now want to mention some important things to look forward to
in the next few months, starting with the 35th anniversary of our
organization. In 1984, the Denver Gem and Mineral Council
designated the show theme as “Year of the Fossil” and our founders
Bryan Cooney and Jordan Sawdo were asked to organize speakers
2 TRILOBITE TALES | MARCH 2020
Dave Fangrow