A Systematic Reappraisal and Quantitative Study of the Non

Canadian Journal of Earth Sciences

A systematic reappraisal and quantitative study of the non- marine teleost fishes from the late Maastrichtian of the Western Interior of North America – evidence from vertebrate microfossil localities

Journal: Canadian Journal of Earth Sciences

Manuscript ID cjes-2020-0168.R2

Manuscript Type: Article

Date Submitted by the 20-Nov-2020 Author:

Complete List of Authors: Brinkman, Donald B.; Royal Tyrrell Museum of Palaeontology Divay, Julien; Royal Tyrrell Museum of Palaeontology DeMar, David;Draft National Museum of Natural History Smithsonian Institution, Department of Paleobiology Wilson Mantilla, Gregory P.; University of Washington, Department of Biology; University of Washington, Department of Biology

Scollard, Hell Creek, Lance, Cretaceous/Paleogene mass extinction, Keyword: Esocidae, Acanthomorpha

Is the invited manuscript for consideration in a Special Tribute to Dale Russell Issue? :

1 A systematic reappraisal and quantitative study of the non-marine teleost fishes from the late

2 Maastrichtian of the Western Interior of North America – evidence from vertebrate microfossil

3 localities

5 Donald B. Brinkman1*, Julien D. Divay2, David G. DeMar, Jr.3, and Gregory P. Wilson

6 Mantilla4,5

8 1Royal Tyrrell Museum of Palaeontology, Box 7500, Drumheller, AB, Canada, T0J 0Y0.

9 [email protected]; and Adjunct professor, Department of Biological Sciences, University 10 of Alberta, Edmonton, Alberta Draft 11 2Royal Tyrrell Museum of Palaeontology, Box 7500, Drumheller, AB, Canada, T0J 0Y0.

12 [email protected]

13 3Department of Paleobiology, National Museum of Natural History, Smithsonian Institution,

14 Washington, DC, 20560, U.S.A. [email protected]

15 4Department of Biology, University of Washington; Seattle, WA, 98195, USA

16 5Department of Paleontology, Burke Museum of Natural History and Culture, University of

17 Washington, Seattle, WA 98195, USA

20 *Corresponding author: [email protected], 403 436-0230

21 Abstract

22 The diversity and distribution of non-marine teleost fishes in the Western Interior of

23 North America during the late Maastrichtian is documented based on isolated elements from

24 vertebrate microfossil localities in the Hell Creek Formation of Montana, the Lance Formation of

25 Wyoming, and the Scollard Formation of Alberta. A minimum of 20 taxa are recognized based

26 on >1900 abdominal centra and tooth-bearing elements. These include two elopomorphs, six

27 osteoglossomorphs, three ostariophysans, one esocid, six acanthomorphs, and two taxa of

28 unknown relationships. These assemblages differ from late Campanian assemblages in the

29 absence of the Clupeomorpha and the presence of the Perciformes. Within the Hell Creek

30 Formation, we record patterns in the relative abundances of the most abundant taxa leading up to

31 the Cretaceous/Paleogene (K/Pg) boundary.Draft Most notably, acanthomorphs increased in

32 abundance up-section whereas a group of osteoglossomorphs represented by Coriops and/or

33 Lopadichthys concurrently decreased in abundance. Conversely, some teleosts exhibited more

34 stable or slightly fluctuating relative abundances through the formation (Wilsonichthyidae,

35 Esocidae). These late Maastrichtian teleost assemblages are of higher diversity than an early

36 Eocene assemblage from Wyoming that is preserved under similar taphonomic conditions. This

37 pattern either suggests that lower Cenozoic deposits in the Western Interior are insufficiently

38 sampled or that the K/Pg mass extinction event adversely affected non-marine teleosts.

39 Key words: Scollard, Hell Creek, Lance, Cretaceous, Cretaceous/Paleogene mass extinction,

40 Osteoglossomorpha, Elopomorpha, Ostariophysi, Esocidae, Acanthomorpha, Diversity

41 Introduction

42 Vertebrate microfossil assemblages, which are concentrations of small disarticulated and

43 isolated vertebrate hard parts (e.g. bones, teeth, and scales), have long been recognized as an

44 exceptional source of information on the diversity and distribution of vertebrates in the Late

45 Cretaceous of the Western Interior of North America (Sankey and Baszio 2008). One component

46 of these assemblages that remains poorly understood are the teleost fishes (Actinopterygii,

47 Teleostei). Large samples of isolated elements from teleosts have been obtained from such

48 localities through the use of bulk sampling techniques (e.g., McKenna 1962). Early studies of

49 this material resulted in several taxa being named on the basis of tooth bearing elements (Estes

50 1964, 1969a, 1969b; Wilson et al. 1992), although those authors recognized that the diversity of

51 teleosts was underestimated because manyDraft distinctive elements (e.g. vertebral centra) could not

52 be placed in any lower-level taxon. More recent studies used a morphotype approach to more

53 fully inventory the kinds of elements of teleosts present in vertebrate microfossil fossil

54 assemblages (Brinkman and Neuman 2002; Neuman and Brinkman 2005; Brinkman et al. 2013,

55 2014, 2017; Brinkman 2019). Morphologically distinctive elements that were not assigned to

56 lower-level taxa but appeared to be taxonomically distinctive (i.e., not the result of regional

57 variation within a taxon) were treated as separate operational taxonomic units (i.e., given unique

58 alpha-numeric designations). In turn, teleosts became more fully incorporated into studies of the

59 paleobiogeography and diversity of vertebrates through the Late Cretaceous. The resulting

60 studies showed that teleosts underwent an increase in diversity through the Late Cretaceous that

61 was punctuated by two major pulses of turnover, one in the late Turonian and one in the late

62 Campanian, with intercontinental dispersal playing a role in both of those periods of faunal

63 change (Brinkman et al. 2013; Newbrey et al. 2009).

64 In this paper we document the teleost assemblages of late Maastrichtian age based on

65 recently collected samples from the Hell Creek Formation and previously unstudied samples

66 from the Lance and Scollard formations. This material provides additional data on the taxonomic

67 diversity, paleobiogeographic distributions, and changes in the relative abundances of teleost

68 fishes during the late Maastrichtian and thus gives a more complete understanding of teleost

69 assemblages of the Western Interior of North America immediately prior to the

70 Cretaceous/Paleogene (K/Pg) mass extinction event.

72 Dedication

73 This paper is dedicated to the late Dale Russell, who continues to be a source of

74 inspiration to all of us. Dale often took Draftan innovative approach, thinking “outside the box” of

75 conventional wisdom and was fearless in the intellectual pursuit of his ideas. One of these was

76 the possibility that the K/Pg extinction event had an extraterrestrial cause (Russell and Tucker,

77 1971), an idea that was very much outside mainstream thought in the early 1970s. This led to a

78 symposium exploring the possibility that the K/Pg extinction event had an extraterrestrial cause

79 that was held in 1976 during which the need for chemical studies of the boundary horizon was

80 recognized (Beland et al. 1977). We hope that our paper, which has implications for

81 understanding the effects of the K/Pg mass extinction on freshwater fishes, will help provide

82 recognition of Dale’s idea as one of his many insights about the history of life that set the stage

83 for subsequent revolutions in scientific thought.

85 Localities Sampled

86 This study is based on samples from eight vertebrate microfossil localities in the Hell

87 Creek Formation and one in each of the Scollard and Lance formations (Fig. 1). The Hell Creek

88 sites are all located in Garfield County, Montana, USA, and they span ~71.2 m of the ~89.5-m-

89 thick Hell Creek Formation. The material studied is in the collections of the University of

90 California Museum of Paleontology (UCMP), Berkeley, California, the University of

91 Washington Burke Museum (UWBM), Seattle, Washington, and the Museum of the Rockies

92 (MOR), Bozeman, Montana, all in the USA. The MOR material discussed herein is currently

93 housed at the UWBM. This material was collected by teams led by William A. Clemens (UCMP,

94 1972–1996) and one of us (GPWM at UCMP and UWBM, 1998–present). Of the eight localities

95 in the Hell Creek Formation, three are in the lower third of the unit (LHC), one is from the

96 middle third (MHC), and four are from Draftthe upper third (UHC). In stratigraphic succession with

97 their position in meters as measured above the base of the Hell Creek Formation and below the

98 Hell Creek/Ft. Union formational contact (X / -X m) these localities are: LHC, i) UCMP V99220

99 (=UWBM C1103, Tuma: 13.1 / -76.4 m); ii) UCMP V99227 (=MOR HC-597 and UWBM

100 C1111, Manzoni: 20.4 / -69.1 m); iii) UCMP V99369 (=UWBM C1115, Celeste’s Magnificent

101 Microsite: 30.5 / -59 m); MHC, iv) UWBM C1153 (=UCMP V82022, Hartless: 48.3 / -41.2 m);

102 UHC, v) UWBM C1529 (Hot Feet: 70 / -19.5 m); vi) UCMP V77130 (=UWBM C1917, Hauso

103 1: 83.2 / -6.3 m); vii) UCMP V73087 (=UWBM C1614, Flat Creek 5: 84.3 / -5.2 m); and, viii)

104 MOR HC-656 (=UWBM C1370 and UCMP V75162, Worm Coulee 5: 87.1 / -2.4 m). Two other

105 Hell Creek localities, one from the lower part of the MHC (UWBM C1401, Impossible Ridge:

106 35 / - 54.5 m) and one from the UHC (UWBM C1151, From Mars, 75 / - 14.5 m), are also

107 included to account for additional stratigraphic occurrences of Platacodon nanus. Stratigraphic

108 heights of these localities are based on Wilson (2014 and references therein) and Wynd et al.

109 (2020).

110 Specimens from the Lance Formation come from a single locality, UCMP V5711, (Bushy

111 Tailed Blowout), which is located along Lance Creek, Powder River Basin, Niobrara County,

112 Wyoming, USA. The material studied is in collections of the University of Alberta Laboratory

113 for Vertebrate Palaeontology (UALVP), Alberta, Canada. Paleomagnetic evidence indicates that

114 the locality is in the Cretaceous part of magnetochron C29r, equivalent to the upper Hell Creek

115 localities of Garfield County, Montana (Keating and Helsing 1983; Cifelli et al. 2004; also see

116 Wilson et al. 2010:fig. 1).

117 Specimens from the Scollard Formation also come from a single locality, KUA2, located

118 on Griffith’s farm south of Dry Island ProvincialDraft Park, Alberta, Canada. This locality was

119 discovered by Lilligraven (1969). Fossiliferous matrix from this locality was screenwashed by

120 the Royal Tyrrell Museum and fossil material from it is in the collections of the Royal Tyrrell

121 Museum of Palaeontology (TMP), Drumheller, Alberta, Canada.

122 In addition, specimens from the Bug Creek Anthills are used to aid in describing some of

123 the previously unrecognized taxa described here. Bug Creek Anthills is an exceptionally fossil-

124 rich Hell Creek Formation locality located in McCone County, Montana, that preserved a mixed

125 upper Maastrichtian/lower Paleocene assemblage. Thus, the geologic age of individual

126 specimens is uncertain. However, the morphological detail preserved in these fossils makes them

127 very useful for fully characterizing the morphology and range of variation in some of the taxa

128 represented in localities of known age, especially in the case of taxa represented by relatively

129 few specimens. Specimens from the Bug Creek Anthills studied here are in the collections of the

130 Royal Ontario Museum (ROM), Toronto, Ontario, Canada, and UCMP.

131

132 Methods

133 This study is based on material from vertebrate microfossil localities that were mostly

134 bulk sampled through the use of underwater screenwashing techniques (McKenna 1962); some

135 specimens were surface collected. As typical for such localities, fishes are represented by

136 disarticulated, isolated elements. The combined taxonomic/morphotype approach adopted by

137 Brinkman et al. (2013, 2014, 2017) in studies of fishes from the Grand Staircase/Escalante

138 region of Utah, USA, the Hell Creek Formation of Montana, and the Milk River Formation of

139 Alberta, is used to ensure that all available material is incorporated into the analysis of the

140 diversity of teleosts present. As with previous studies of fishes from Late Cretaceous vertebrate

141 microfossil localities (Brinkman and NeumanDraft 2002; Neuman and Brinkman 2005; Brinkman et

142 al. 2013, 2014, 2017), interpretations of the diversity of teleosts are based primarily on

143 abdominal centra and tooth-bearing elements. Whereas morphologically distinct dentaries are

144 generally taxonomically distinct, vertebral elements must be evaluated more cautiously because

145 of variation along the vertebral column. The range in morphological variation along the column

146 in extant teleosts provides a framework in which to evaluate whether distinct morphotypes are

147 from different regions of the vertebral column or represent taxonomically distinct groups.

148 Acanthomorph and ostariophysan teleosts are particularly challenging because of the high degree

149 of variation along the column in members of these groups. To ensure that this morphological

150 diversity reflects taxonomic diversity of acanthomorphs present rather than variation along the

151 column, the anterior-most vertebra, referred to as the atlas centrum by Patterson (1993), was

152 emphasized in defining distinct morphotypes. This centrum is referred to here as the first

153 abdominal vertebra because it is not homologous with the tetrapod atlas. More posterior

154 abdominal centra were associated with the first centrum morphotypes based on shared or

155 transitional morphological features, size-frequency distribution patterns, and patterns of

156 geographic distribution. Morphotypes based on more posterior abdominal centra were

157 recognized only when they displayed morphological features that clearly separated them from all

158 the first abdominal centra that were observed.

159 To identify the taxa present, comparisons were made with extant and fossil specimens. A

160 list of Recent teleost specimens used for comparison with the fossil material is given in appendix

161 1. The collections of fossil fishes in the UALVP and the TMP were also particularly useful. In

162 addition to articulated specimens of teleosts of Cretaceous and Paleocene age, Eocene Green

163 River Formation fishes were examined because Divay and Murray (2016a) and Divay et al.

164 (2019) were able to use articulated GreenDraft River specimens to identify isolated elements of the

165 clupeomorph Diplomystus and gonorynchid Notogoneus in Late Cretaceous assemblages. As

166 well, the discovery of articulated teleost fishes of small size from a locality in the Scollard

167 Formation has allowed isolated elements to be identified (Murray et al. 2016, 2019).

168 Terms used to refer to morphological features present on the abdominal centra are shown

169 in Figure 2. To document the morphological variation within the taxonomic units recognized, the

170 descriptions are accompanied by an extensive series of photographs. Specimens were dusted

171 with ammonium chloride before being photographed to emphasize surface relief. Photographs

172 were taken with a Sony Cyber-shot digital still camera attached to a Wild MC3 microscope.

173 Comparisons of faunal assemblages preserved in different localities or formations are

174 based on both presence/absence and relative abundance data. Badgley (1986) concluded that

175 where formerly articulated material has been widely dispersed and has accumulated as isolated

176 specimens, the minimum number of elements of a taxon is the best basis for documenting

177 differences in the relative abundance of taxa between sites. Because the fossil assemblages

178 included in this study accumulated under generally similar taphonomic conditions in channel,

179 overbank, and pond/lake deposits (Eberth 1990), major differences in relative abundance of taxa

180 in localities being compared are interpreted as evidence for differences in abundance of those

181 taxa in the original communities being compared. Brinkman (2008) argued that the biases

182 introduced by the taphonomic processes can be further minimized by focusing on

183 taphonomically similar elements (e.g. teeth vs teeth, centra vs centra). Thus, only centra are used

184 to quantify the differences in the relative abundance of teleosts at the localities being compared.

185

186 SYSTEMATIC PALEONTOLOGY

187 Division TELEOSTEI Müller, 1846Draft (sensu Patterson and Rosen, 1977)

188 Subdivision ELOPOMORPHA Greenwood Rosen, Weitzman, and Myers, 1966

189 Order ELOPIFORMES Greenwood, Rosen, Weitzman, and Myers, 1966

190 Genus et sp. indet.

191 (Fig. 3A)

192 1997: Teleost F, Eberth and Brinkman, p. 57

193 2002: Morphoseries IA-3, Brinkman and Neuman, p. 141, fig. 1.18–1.27.

194 2014: Elopiformes, Brinkman et al., p. 210, fig. 10.14A–C

195 2017: Elopiformes genus et sp. indet., Brinkman et al., p. 18–19, fig. 8

196 2019: Elopiformes gen. indet. (small elopomorph), Brinkman, p. 115, fig. 1

197 Referred material: Lance Formation (Bushy Tailed Blowout locality): UALVP 58837, one

198 complete and one partial centrum.

199 Description: Two centra are known from the Lance Formation, one of which is complete (Fig.

200 3A). This complete centrum is anteroposteriorly short, has widely separated neural arch and

201 parapophyseal articular pits, and has numerous fine ridges of bone extending between the ends of

202 the centrum on its lateral surfaces. The neural arch articular pits are relatively small, shallow,

203 circular pits bordered posterolaterally by a raised edge. The parapophyseal pits are deeper,

204 rectangular pits that are more widely spaced from one another.

205 Remarks: This centrum morphology is particularly similar to that of the extant genus Elops

206 Forsskål, 1775. Elopomorphs are represented in Cretaceous vertebrate microfossil sites in

207 Alberta and Utah by both elopiforms and albuliforms (Brinkman et al. 2013). Specimen UALVP

208 58837 is included in the Elopiformes because it is similar to extant members of the group and

209 different from those of albuliforms in the arrangement of the bony ridges that extend between the

210 anterior and posterior ends of the centrum.Draft Albuliforms, such as the extant genus Albula and the

211 Albula-like centra that Neuman and Brinkman (2005) referred to Paralbula, have bony ridges

212 that are grouped together into bundles forming distinct bars extending between the ends of the

213 centrum, whereas elopiforms have numerous thin bony ridges that are evenly spaced.

214 Although the Elopiformes are primarily marine, they are widely distributed in the Upper

215 Cretaceous non-marine formations of the Western Interior of North America: the Cenomanian to

216 Santonian of Utah (Brinkman et al. 2013), and the Santonian to upper Campanian formations of

217 Alberta (Brinkman et al. 2017; Brinkman 2019). Two genera of elopiforms are present in the

218 upper Campanian Dinosaur Park Formation of Alberta, the large-bodied Paratarpon, which is

219 represented by two articulated specimens as well as isolated elements, and an unnamed small

220 bodied taxon represented by isolated elements. The elopomorph centrum from the Lance

221 Formation is most similar to the small-bodied taxon in proportions and in the structure of the

222 parapophyseal articular surface.

223

224 Order ALBULIFORMES sensu Forey et al., 1996

225 Suborder ALBULOIDEI sensu Forey et al., 1996

226 Family PHYLLODONTIDAE Dartevelle and Casier, 1943

227 Phyllodus paulkatoi Estes and Hiatt (1978)

228 (Fig. 3B–C)

229 1969: cf. Paralbula casei, Estes et al., p. 11

230 1969: Phyllodus toliapicus, Estes, p.319–321, fig. 1A–C

231 1978: Phyllodus paulkatoi, Estes and Hiatt, p. 1–10. Fig. 1–2.

232 1989: Phyllodus paulkatoi, Bryant, p. 26.

233 Referred material: Lance Formation: UALVPDraft 58837

234 Description: These round, flat teeth have an enamel-covered occlusal surface with variable

235 surface ornamentation. Despite being otherwise essentially identical, some of these teeth have an

236 occlusal surface covered in small tubercles (Fig. 3B), whereas in others this surface is smooth

237 (Fig. 3C). Most characteristically, these elements are occasionally found in stacks of replacement

238 teeth.

239 Remarks: Phyllodus paulkatoi was described by Estes and Hiatt (1978) on the basis of a single

240 basibranchial tooth plate from the Hell Creek Formation and partial tooth plates from the lower

241 Paleocene Tullock Member of the Fort Union Formation. Phyllodus, along with the late

242 Campanian taxon Paralbula, are members of the Phyllodontidae, an extinct group of albuloid

243 fishes that have flattened button-like teeth that are arranged in multiple sets of replacement teeth.

244 In Phyllodus the teeth are superimposed or stacked, whereas in Paralbula the teeth are

245 alternating or irregularly arranged. Estes et al. (1969) notes that the teeth of Phyllodus also differ

246 from those of Paralbula in being smoother, and based on this difference in surface texture, he

247 referred a partial tooth plate containing two teeth and an isolated tooth from the Bug Creek

248 Anthills locality to Paralbula despite the superimposed arrangement of the teeth in the tooth-

249 plate (Estes et al. 1969). However, specimens of Phyllodus from an early Paleocene locality in

250 the Tullock Member (UCMP 191568/V73080) show that the surface texture of the teeth varies,

251 with both rough (Fig. 3B) and smooth (Fig. 3C) teeth present. Thus, it is concluded that surface

252 texture is not a reliable feature for distinguishing teeth of Phyllodus and Paralbula. Because the

253 Bug Creek specimens show a pattern of stacking like that of Phyllodus, it is considered more

254 likely that they are from that genus. As a result, only a single phyllodontid, Phyllodus paulkatoi,

255 is recognized here as being present in the late Maastrichtian of the Western Interior of North

256 America (contra Estes et al. 1969). PhyllodusDraft is rare, and no additional specimens of this taxon

257 from the upper Maastrichtian formations were observed in samples studied in this analysis.

258

259 Superorder OSTEOGLOSSOMORPHA Greenwood et al., 1966

260 Order OSTEOGLOSSIFORMES Berg, 1940

261 Family WILSONICHTHYIDAE Murray, Newbrey, Neuman, and Brinkman, 2016

262 Wilsonichthys Murray, Newbrey, Neuman, and Brinkman, 2016

263 (Fig. 4)

264 2013: Genus et sp. indet. type BvE, Brinkman et al., p. 225–226, fig. 10.27

265 2014: Genus and species indet. type B-vE, Brinkman et al. p. 261, fig. 11C–D

266 2016: Wilsonichthys, Murray et al., p. 1–14, fig. 7–8

267 2017a: Wilsonichthys, Brinkman et al., p. 24, fig. 13

268 2019: ?Wilsonichthys (centrum type B-vE), Brinkman, p. 119, Fig. 4

269 2019: ?Wilsonichthys (centrum type B-vA), Brinkman, p. 119, fig. 4C–D

270 Referred material: Hell Creek Formation: UCMP 198883/V99369, dentary of Wilsonichthys

271 aridinsulensis; UCMP 230683/V99220, dentary of Wilsonichthys sp.; UCMP 191597/V99369,

272 centra type B-vE; UWBM 106395/C1103, centra type B-vE; UWBM 106485/C1153, centra type

273 B-vE; UWBM 106524/C1529, centra type B-vE; UWBM 106531/C1529, centra type B-vE;

274 UWBM 106532/C1529, centra type B-vE; UWBM 106539/C1529, centra type B-vE; UCMP

275 191596/V99369, centra type B-vA; UCMP 230619/V73087, centra type B-vA; UCMP

276 230672/V99220, centra type B-vA; UWBM 98094/C1153, centrum type B-vA; UWBM

277 106372/C1103, centrum type B-vA; UWBM 106373/C1103, centrum type B-vA; UWBM

278 106378/C1103, centrum type B-vA; UWBM 106386/C1103, centra type B-vA; UWBM

279 106396/C1103, centra type B-vA; UWBMDraft 106548/C1529, centrum type B-vA; MOR 9343/HC-

280 597, centrum type B-vA; MOR 9384/HC-597, centrum type B-vA; MOR 9438/HC-656, centrum

281 type B-vA.

282 Lance Formation (Bushy Tailed Blowout locality): UALVP 56054, centra type B-vE.

283 Scollard Formation (KUA2 locality): TMP 2012.20.1493, articulated skeleton, the type

284 specimen of Wilsonichthys aridinsulensis; TMP 2009.13.62, anterior end of dentary and anterior

285 end of maxilla of Wilsonichthys aridinsulensis; TMP 2009.13.5, centra type B-vE, TMP

286 2009.13.73, one centrum type B-vE, TMP 2009.13.74, five centra type B-vE, TMP 2009.13.218,

287 one centrum type B-vE; TMP 2009.13.221, one centrum type B-vE; TMP 2009.13.228; one

288 centrum type B-vE; TMP 2009.13.348, three centra.

289 Description: The dentary is relatively short and deep, has a truncated anterior end, and an

290 elongate groove for the mandibular sensory canal on the lateral surface of the dentary that is

291 located approximately midway between the dorsal and ventral edges (Fig.4A). The teeth are

292 relatively large and conical, and a tooth near the symphysis is slightly enlarged relative to the

293 adjacent teeth of the marginal tooth row.

294 Centra (Fig. 4C–G) are relatively small, with circular anterior and posterior articular

295 surfaces with a central notochordal foramen. Neural arches are fused, with long bases spanning

296 the entire length of the centrum, bordering a median longitudinal dorsal pit. A pair of thin

297 longitudinal ridges of bone may be present (Fig. 4F–G), or absent (Fig. 4D–E), bisecting this

298 dorsal pit. The lateral surface of the centrum is largely occupied by a large parapophyseal

299 articular pit. The pit is relatively shallow, and lined by relatively flat, featureless bony surfaces

300 (e.g., Fig. 4E), although shallow plications are occasionally visible on these surfaces (e.g., Fig.

301 4D). Longitudinal bony ridges extend between anterior and posterior ends of the centrum on the

302 ventrolateral margins of the centrum, borderingDraft a deep, median ventral pit. In some cases (e.g.,

303 Fig. 4G), the ventrolateral ridges converge somewhat at approximately mid-length of the

304 centrum, resulting in an hourglass-shaped ventral pit.

305 Remarks: Wilsonichthys aridinsulensis was erected by Murray et al. (2016) on the basis of two

306 articulated skeletons from the upper Maastrichtian age portion of the Scollard Formation of

307 Alberta. Based on comparison with these specimens, isolated dentaries from the Scollard and

308 Hell Creek formations were referred to this genus. Murray et al. (2016) also recognized the

309 presence of a second unnamed species of Wilsonichthys in the Hell Creek Formation based on a

310 second dentary in which the groove for the mandibular sensory canal extends to the anterior end

311 of the dentary, and, as indicated by the diameter of the bases of the broken teeth, the teeth are

312 smaller, and the anterior teeth decrease in size compared to those mid-way along the tooth row

313 (Fig. 4B). The taxon represented by this second dentary is referred to as Wilsonichthys sp. in

314 Table 1.

315 Centra were partially visible in the type specimen of Wilsonichthys aridinsulens (TMP

316 2012.020.1493), and two centrum morphotypes that occur in the late Maastrichtian showed

317 similarities with those in the type specimen (e.g., Murray et al. 2016, fig. 8). These had been

318 previously described as centrum type B-vA and B-vE by Brinkman et al. (2014:fig. 11). They

319 differ in that in centrum type B-vA a pair of thin ridges are present dorsally between the bases of

320 the neural arch and ventral processes are present on the posterior end of the centrum (Fig. 4F–G

321 versus 4C–E, respectively). Both are found in the Hell Creek Formation, although only one,

322 centrum type B-vE, co-occurred with the type specimen in the Scollard Formation, and therefore

323 was thought to be the most likely candidate for being from the type species W. aridinsulensis.

324 However, because centrum type B-vA is morphologically similar to type B-vE in general

325 features, it is tentatively included in the Draftgenus as representative of an indeterminate species, and

326 is referred to as ?Wilsonichthys in Table 2.

327 Wilsonichthys aridinsulensis was widely distributed paleobiogeographically in the late

328 Maastrichtian of the northern Western Interior of North America. Dentaries of W. aridinsulensis

329 are present in the Hell Creek and Scollard formations, and centra of type B-vE are present in the

330 Hell Creek, Scollard, and Lance formations. In contrast, the dentary referred to Wilsonichthys sp.

331 and the centra referred to ?Wilsonichthys are only present in the Hell Creek Formation. Although

332 it is likely that these are from the same kind of fish, this cannot be confirmed at present, therefore

333 these are treated as separate taxonomic units. However, only one of these is used in estimates of

334 the total diversity of teleost fish during the late Maastrichitian.

335

336 Order HIODONTIFORMES Taverne, 1979

337 Family HIODONTIDAE Cuvier and Valenciennes, 1846

338 Gen. et sp. indet.

339 (Fig. 5)

340 2001: Teleost indet., Peng, Russell, and Brinkman, p. 18, Plate 4, fig. 10–11

341 2002: Morphoseries IIB-1, Brinkman and Neuman, p. 147–149, fig. 6

342 2005: Morphoseries IIB-1 (Hiodontidae), Neuman and Brinkman, p. 180, fig. 9.8F

343 2013: Hiodontidae, Newbrey et al., fig. 2

344 2013: Hiodontiformes, Brinkman et al., p. 209, fig. 10.12

345 2014: Hiodontidae gen et sp. indet 1, Brinkman et al., p. 253, fig. 5

346 2017a: Hiodontidae Genus et sp. indet., Brinkman et al., p. 24–27, fig. 14

347 2019: Hiodontidae Genus et sp. indet., Brinkman, p. 120, fig. 5

348 Referred material: Hell Creek Formation:Draft UCMP 191590/V99369, three centra of small size,

349 including a first abdominal centrum; UCMP 230617/V73087, four centra of small size, including

350 a first abdominal centrum; UCMP 230684/V99220, centra of small size; UWBM 98060 /C1153,

351 centra of small size; UWBM 106549/C1529, centrum of small size; MOR 9404/HC-597,

352 centrum of small size; UCMP 191595/V99369, centrum of large size; UCMP 191867/V77130,

353 centrum of large size; UCMP 230616/V73087, two centra of large size, including a first

354 abdominal centrum.

355 Lance Formation (Bushy Tailed Blowout locality): UALVP uncatalogued, centrum of

356 small size.

357 Scollard Formation (KUA2 locality): TMP 2015.37.23, one abdominal centrum of small

358 size.

359 Description: As in extant hiodontids, the anterior-most centrum is distinctive in having a flat

360 anterior articular surface subdivided into distinct lobes and small, round neural arch articular pits

361 on the posterior half of the centrum (Fig. 5A, D). The neural arches of the anterior and mid

362 abdominal centra are also autogenous, and the neural arch articular pits are shallow, oval

363 depressions of characteristic shape (Fig. 5E, F). Parapophyses are fused to the centrum, and are

364 directed ventro-laterally. Pleural ribs articulate directly with the centrum in pits located postero-

365 dorsally to the parapophyses (Fig. 5 A, B, E, F).

366 Remarks: Hiodontids are represented in the Lance, Hell Creek, and Scollard formations by

367 centra. Two taxa were recognized in the Hell Creek Formation by Brinkman et al. (2014:figs. 5,

368 6) based on size and morphology of the centra. The small centra are typically about two

369 millimetres in diameter (Fig. 5 A–C). The first abdominal centrum has four distinct lobes

370 anteriorly for articulation with the basioccipital (Fig. 5A). The larger centra reach 10 mm in

371 diameter (Fig. 5D–F). The anterior surfaceDraft of the first abdominal centrum of the large taxon

372 differs in that the two ventral lobes are coalesced, so that there are three, rather than four, distinct

373 lobes in anterior view (Fig. 5D). The small-bodied taxon occurs in all three formations (i.e., Hell

374 Creek, Lance, and Scollard), but the large-bodied taxon is only present in the Hell Creek

375 Formation.

376

377 Order INDET.

378 Coriops Estes, 1969b

379 (Fig. 6A)

380 1969: Coriops amnicolus, Estes, p. 7–9, plate 4

381 1989: Coriops amnicolus, Bryant, p. 25

382 1990: Teleost D, Brinkman, p. 44, fig. 4

383 2005: Coriops, Neuman and Brinkman, p. 174–176, fig. 9.6A

384 2010: Coriops, Larson, Brinkman, and Bell, p. 1165, fig. 5A

385 2013: Coriops, Newbrey et al., fig. 3F–I

386 2013: Coriops, Brinkman et al., p. 207-209, fig. 10.11 A–B

387 Referred material: Lance Formation (Bushy Tailed Blowout locality): UALVP 58853,

388 basibranchial element of small size.

389 Scollard Formation (KUA2 locality): TMP 2009.13.67, partial basibranchial; TMP

390 2009.13.267, partial basibranchial.

391 Description: Coriops was named on the basis of parasphenoid and basibranchial tooth-plates

392 from the upper Maastrichtian Lance and Hell Creek formations that exhibited robust, blunt,

393 pillar-like teeth (Este, 1969b). In a partial basibranchial from the Lance Formation (Fig. 6A), the

394 teeth vary in size, with some located towardsDraft the center of the element being about half the

395 diameter of the largest teeth. The ventral surface is highly fenestrated, giving a lacy appearance.

396 A shallow, broad, mid-line groove is present.

397 Remarks: Coriops was originally placed in the Albulidae by Estes (1969b), but from

398 comparison with extant teleosts, Neuman and Brinkman (2005) suggested that Coriops was an

399 osteoglossomorph and referred distinctive dentaries, premaxillae and centra to the genus.

400 However, centra were subsequently shown to differ little from those of a second

401 osteoglossomorph, Lopadichthys, which was represented by three articulated specimens from the

402 upper Paleocene Paskapoo Formation (Murray et al, 2018). Although this confirms the

403 osteoglossomorph affinities of the centra referred to Coriops, it implies that these centra are not

404 diagnostic at a generic level and are considered separately as evidence for a higher-level

405 taxonomic group that includes Coriops and Lopadichthys among other osteoglossomorphs (see

406 below).

407

408 Aff. Lopadichthys Murray, Zelenitsky, Brinkman, and Neuman, 2018

409 (Fig 6B)

410 2018: Lopadichthys, Murray et al., p. 1–38

411 Referred material: Lance Formation (Bushy Tailed Blowout locality): UALVP 56055, dentary.

412 Description: Aff. Lopadichthys is represented by a single dentary from the Lance Formation.

413 The dentary is triangular in shape in lateral view with a concave ventral margin. In occlusal

414 view, the dentary is curved towards the midline anteriorly. Two rows of teeth are present along

415 its dorsal edge. Based on the diameter of their bases, the teeth of the inner row and outer row are

416 subequal in size. The sensory canal is located along ventral edge of dentary. Two pores of

417 moderate size are present. Draft

418 Remarks: Lopadichthys was erected by Murray et al. (2018) on the basis of three articulated

419 skeletons. The presence of an osteoglossomorph with affinities to Lopadichthys in the Lance

420 Formation of Wyoming is documented by an isolated dentary (Fig. 6B). As in dentaries of

421 Coriops from the Dinosaur Park Formation (Neuman and Brinkman 2005:fig. 9.6C–D) multiple

422 rows of teeth are present. The dentary differs from that of Coriops in that the lateral-most row of

423 teeth is restricted to the dorsal edge of the dentary rather than the dorso-lateral surface, and the

424 bases of the teeth face dorsally rather than dorso-laterally. Also, based on the diameter of the

425 tooth bases, the size of the teeth on the two rows does not differ significantly, in contrast to

426 Coriops where the lateral row of teeth is larger. In lateral view, the dentary differs from that of

427 Coriops and is similar to that of Lopadichthys in that the sensory canal is located near its ventral

428 edge rather than the middle of the element, as well as in that the sensory canal pores are

429 relatively small. Although none of the available dentaries of Coriops are complete, the dorso-

430 ventral depth of the dentary, as seen in lateral view, does not increase posteriorly over the length

431 of the tooth row (Neuman and Brinkman 2005:fig. 9.6C–D), in contrast to Lopadichthys and the

432 Lance Formation specimen, in which the dentaries are more triangular in lateral view (Murray et

433 al. 2018:fig. 16).

434 Specimen UALVP 56055 provides evidence for an osteoglossomorph with similarities to

435 Coriops and Lopadichthys during the late Maastrichtian. Although this dentary approaches

436 Lopadichthys more closely than Coriops in overall shape and position of the sensory canal, it

437 differs from the former in having two rows of teeth and in being more curved medially when

438 seen in occlusal view. Thus, it is considered taxonomically distinct, and is referred to as aff.

439 Lopadichthys in Table 1.

440 Draft

441 Coriops or Lopadichthys

442 (Fig. 7)

443 1990: Teleost D, Brinkman and Eberth, p. 44–45, fig. 1

444 2001: Teleost D, Peng, Russell, and Brinkman, p. 18, Plate 4, fig. 7–9

445 2002: Morphoseries IIA-1, Brinkman and Neuman, p. 144-146, fig. 4.1–4.11

446 2005: Coriops, Neuman and Brinkman, p. 174–176, fig. 9.6B–D, 9.8D

447 2010: Coriops, Larson, Brinkman, and Bell, p. 1165, fig. 5A

448 2013: Coriops, Newbrey et al., fig. 3

449 2013: Coriops, Brinkman et al., p. 207–209, fig. 10.11

450 2014: Coriops, Brinkman et al. p. 252–253, fig. 4

451 2018: Coriops, Murray et al., fig. 12D–F

452 2019: Coriops, Brinkman, p. 115–119, fig. 3

453 Referred material: Hell Creek Formation: UCMP 230612/V73087, posterior abdominal

454 centrum; UCMP 230613/V77130, mid-abdominal centrum; UCMP 230614/V77130, centra of

455 small size; UCMP 230615/V77130, centra of large size; UCMP 230677/V99220, centra of small

456 size; UCMP 230745/V77130, anterior abdominal centrum; UWBM 98115/C1153, centra of

457 small size; UWBM 106364/C1103, centrum of small size; UWBM 106366/C1103, centrum of

458 large size; UWBM 106367/C1103, centrum of small size; UWBM 106383/C1103, centra of

459 small size; UWBM 106384/C1103, centrum of large size; UWBM 106390/C1103, centra of

460 small size; UWBM 106394/C1103, centra of small size; UWBM 106398/C1103, centrum of

461 large size; UWBM 106399/C1103, centra of large size; UWBM 106402/C1103, centra of large

462 size; UWBM 106483/C1153, centra of small size; UWBM 106491/C1153, centra of small size;

463 UWBM 106521/C1529, centrum of smallDraft size; UWBM 106522/C1529, centrum of large size;

464 UWBM 106529/C1529, centra of small size; UWBM 106534/C1529, centrum of small size;

465 UWBM 106555/C1529, centrum of small size; UWBM 106573/C1917, centrum of large size;

466 MOR 9342/HC-597, centrum of small size; MOR 9347/HC-597, centrum of small size; MOR

467 9350/HC-597, centra of small size; MOR 9352/HC-597, centra of small size; MOR 9353/HC-

468 597, centrum of large size; MOR 9355/HC-597, centrum of small size; MOR 9359/HC-597,

469 centra of small size; MOR 9363/HC-597, centrum of small size; MOR 9364/HC-597, centra of

470 large size; MOR 9367/HC-597, centrum of small size; MOR 9372/HC-597, centrum of small

471 size; MOR 9373/HC-597, centrum of large size; MOR 9378/HC-597, centra of small size; MOR

472 9383/HC-597, centra of small size; MOR 9391/HC-597, centra of small size; MOR 9392/HC-

473 597, centrum of large size; MOR 9395/HC-597, centrum of small size; MOR 9397/HC-597,

474 centrum of small size; MOR 9402/HC-597, centra of small size; MOR 9403/HC-597, centra of

475 large size; MOR 9408/HC-597, centrum of small size; MOR 9409/HC-597, centra of large size;

476 MOR 9412/HC-597, centra of small size; MOR 9413/HC-597, centrum of small size; MOR

477 9414/HC-597, centra of small size; MOR 9418/HC-656, centrum of small size; MOR 9435/HC-

478 656, centrum of large size; MOR 9437/HC-656, centrum of small size; MOR 9441/HC-656,

479 centrum of large size.

480 Lance Formation (Bushy Tailed Blowout locality): UALVP 58845, centra of large size;

481 UALVP 58846, centra of small size.

482 Scollard Formation (KUA2 locality): TMP 2009.13.70, three centra; TMP 2009.13.77,

483 one centrum; TMP 2015.37.25, one centrum.

484 Description: Distinct anterior, mid, and posterior regions of the abdominal vertebral column can

485 be recognized. The centra from the mid-abdominal region (Fig. 7B–D) are shorter than wide and

486 round or slightly higher than wide in endDraft view. The neural arches are autogenous and the

487 articular surfaces for the neural arch are large, oval pits that extend the full length of the centrum.

488 A mid-dorsal pit is present between the neural arch articular pits. This pit is also oval in shape

489 and about half the size of the neural arch articular pits. Parapophyses are vertical flanges that

490 extend laterally from the centrum. The base of the parapophyses is located anterior to the middle

491 of centrum and extends from the lateral edge of the neural arch articular pit to the ventral edge of

492 the centrum. A rib articular pit is present posterior to the parapophyses. The ventral surface of

493 the centrum may have one large mid-ventral pit (Fig. 7D) or a series of smaller pits (Fig. 7B–C).

494 The anterior abdominal centra (Fig. 7A) are similar to the mid-abdominal centra in

495 having autogenous neural arches and a mid-dorsal pit between the neural arch articular pits. They

496 differ from the mid-abdominal centra in that the parapophyses are short and are more strongly

497 ventrally oriented. These processes originate from lower down on the side of the centrum, and

498 therefore do not contact the edge of the neural arch articular pit. The ventral surface of the

499 centrum between the parapophyses is variable. It may be solid or pierced by a series of small

500 foramina rather than a single large mid-ventral pit.

501 Posterior abdominal centra (Fig. 7E) differ from the mid-abdominal centra in having

502 neural arches fused to the centrum. A ridge extends from the neural arch to the tip of the

503 parapophyses. A mid-ventral pit is present.

504 Remarks: Centra referred to Coriops by Neuman and Brinkman (2005) were shown by Murray

505 et al. (2018) to be little different from those of the Paleocene genus Lopadichthys, and thus

506 should be considered as evidence for a member of a larger group of osteoglossomorphs that

507 includes at least those two genera. Because such a group is currently not recognized, they will be

508 referred to below as centra of Coriops/Lopadichthys morphotype. Brinkman (2019) additionally

509 noted the similarity between centra of thisDraft morphotype and those of other osteoglossids, such as

510 those of Phareodus, as documented from the Eocene Bridger Formation by Divay and Murray

511 (2016b), suggesting that centra may not be diagnostic to lower taxonomic levels within the

512 Osteoglossiformes.

513 Centra of Coriops/Lopadichthys morphotype are consistently abundant in all of the upper

514 Maastrichtian localities examined (Table 2). As noted by Brinkman et al. (2014), a distinct

515 bimodal distribution is present of centra of this morphotype in the Hell Creek Formation,

516 suggesting the presence of two closely related taxa. Centra from the Lance and Scollard

517 formations are all of relatively small size.

518

519 Ostariostoma Schaeffer 1949

520 (Fig. 6C–D)

521 1991: Ostariostoma, Grande and Cavender, p. 405–416

522 2005: Teleost unidentified dentary #4, Neuman and Brinkman, p. p176; fig. 9.7D

523 2017: Ostariostoma, Brinkman et al., p. 19–23, figs. 9–10

524 Referred material: Lance Formation (Bushy Tailed Blowout locality): UALVP 56053, four

525 dentaries represented by their anterior end and one complete dentary.

526 Scollard Formation (KUA2 locality): TMP 2009.13.24, anterior end of dentary;

527 TMP2009.13.68, anterior end of dentary.

528 Description: Dentaries here referred to Ostariostoma are present in both the Lance and Scollard

529 formations (Fig. 6D–E). A complete dentary from the Lance Formation is relatively straight and

530 little expanded posteriorly, with the posterior end being approximately twice the height of the

531 anterior end (Fig. 6E). The exceptionally large sensory canal pores occupy more than half the

532 length of the dentary, with the anterior poreDraft being located close to the anterior end of the dentary

533 and the space between the three pores being less than the diameter of the pores.

534 Remarks: Ostariostoma is one of the few teleosts from the Late Cretaceous or early Paleocene

535 of the Western Interior of North America represented by an articulated skeleton (Schaeffer 1949;

536 Grande and Cavender 1991). The single specimen, which is from the upper Maastrichtian to

537 lower Paleocene Livingstone Group in Montana, is preserved as an impression in a hard

538 mudstone. Fine detail is present in the natural mold, allowing for detailed descriptions based on

539 latex peels taken from the original specimen (Grande and Cavender 1991). A dentary from the

540 upper Santonian Milk River Formation was referred to Ostariostoma by Brinkman et al. (2017)

541 on the basis of comparison with a cast of the original articulated specimen. Shared similarities

542 include the presence of three large sensory canal pores near the anterior end of the dentary and a

543 single row of relatively large teeth. Dentaries of this type are present in both the Lance and

544 Scollard formations.

545

546 Subdivision OTOCEPHALA Johnson and Patterson, 1996 (=Ostarioclupeomorpha Arratia

547 1997)

548 Superorder OSTARIOPHYSI Sagemehl, 1885 (sensu Fink and Fink, 1996)

549 Order GONORYNCHIFORMES Berg, 1940

550 Gen. et sp. indet. type H

551 (Fig. 8A-C)

552 2002: Morphoseries IIIA-1, Brinkman and Neuman, p. 150–151, fig. 8.1–8.4

553 2005: Morphoseries IIIA-1 (teleost indeterminate), Neuman and Brinkman, p. 180, fig. 9.8G

554 2013: Genus et sp. indet. type HvB, Brinkman et al., p. 225, fig. 10.26

555 2014: Genus and species indet H-vB, BrinkmanDraft et al., p. 261, fig. 10C

556 2017: ?Ostariostoma, Brinkman et al., p. 21, fig. 10–11

557 2019: Gonorynchiformes gen. et sp. indet. type H, Brinkman, p. 127–129, fig. 11

558 Referred material: Hell Creek Formation: UCMP 191589/V99369, one first abdominal centrum

559 (centrum type HvB).

560 Lance Formation (Bushy Tailed Blowout locality): UALVP 58842, eight abdominal

561 centra (centrum type HvA).

562 Description: The first abdominal centrum (Fig. 8A) is longer than wide. Neural arches are not

563 fused to the centrum and the neural arch articular pits are distinctive oval pits that are separated

564 from each other by a narrow bar of bone. No sign of parapophyses are present. Short postero-

565 ventral processes are present. A shallow sub-rectangular mid-ventral pit is present.

566 The more posterior abdominal centra (Fig. 8B–C) are similar to the first abdominal

567 centrum in being longer than wide. Neural arches are fused to the centrum and a narrow mid-

568 dorsal ridge extends the length of the centrum between the neural arch bases (Fig. 8C), although

569 this can be subdued on some specimens (Fig. 8B). On specimens interpreted as being from a

570 more anterior position on the vertebral column (Fig. 8B), parapophyses are autogenous and

571 distinct parapophyseal pits are present on the ventrolateral surface of the centrum. A ridge

572 extends from the neural arch to the dorsal edge of the parapophyseal pit. On specimens

573 interpreted as being from a more posterior position the parapophyses are fused to the centrum,

574 forming a vertical ridge midway along the length of the centrum (Fig. 8C). A distinctive mid-

575 ventral pit is generally present (Fig. 8C), although in some specimens, the ventral surface is flat

576 (Fig. 8B).

577 Remarks: A gonorynchiform designated gen. et sp. indet. type H by Brinkman (2019) is

578 represented by two distinctive centrum morphotypesDraft that were referred to as centrum types HvA

579 and HvB by Brinkman et al. (2017, 2019). From comparison with the extant gonorynchiform

580 Chanos and gonorynchiform centra described by Divay and Murray (2016a), here we identify

581 centrum type HvB as the first abdominal centrum and type HvA as the more posterior abdominal

582 centra.

583 Teleost gen. et sp. indet. type H was included in the Gonorynchiformes by Brinkman

584 (2019) because centrum type HvB matches the centrum identified as a gonorynchiform Weberian

585 centrum by Divay and Murray (2016a:fig. 4A–B). Following Divay et al. (2019), this element is

586 referred to here to as the first abdominal centrum rather than a Weberian centrum because,

587 although it is part of a sound-conductive system (Grande and Arratia 2010), only otophysans

588 have a true Weberian system.

589 Based on the patterns of distribution and comparison with the centra partially visible in

590 the articulated type specimen of Ostariostoma, Brinkman et al. (2017) suggested that centrum

591 types HvA and HvB may be from that genus. However, Ostariostoma has been included in the

592 Osteoglossomorpha, either as a member of the Hiodontiformes (Grande and Cavender 1991) or

593 the sister-taxon of Osteoglossiformes (Hilton 2002; Wilson and Murray 2008; Lavoué 2016). If

594 centrum types HvA and HvB are from Ostariostoma, this would imply a gonorynchiform rather

595 than an osteoglossomorph relationship. This possibility was considered further by Murray et al.

596 (2018), who noted that the elongate body shape of Ostariostoma is similar to that of

597 gonorynchiforms. Nevertheless, pending the discovery of additional specimens that confirm the

598 association of the dentaries referred to Ostariostoma and the centra of teleost indet type H, these

599 are treated as distinct operational taxonomic units. However, to avoid inflating the apparent

600 diversity, only one of these operational taxonomic units is here included in estimates of total

601 diversity of teleost fishes during the lateDraft Maastrichtian.

602 Centra of teleost indet. type H are widely distributed in the Late Cretaceous of the

603 Western Interior: the Santonian Milk River Formation, the upper Campanian Belly River Group

604 of Alberta, and the Turonian Smokey Hollow Member of the Straight Cliffs Formation of Utah

605 (Brinkman et al. 2013, 2017; Brinkman 2019). They have a patchy distribution, generally being

606 rare but occurring in moderate to high abundance in some localities. In the late Maastrichtian,

607 they are relatively abundant in the Lance Formation, present but rare in the Hell Creek

608 Formation, and absent in the Scollard Formation (Table 2).

609

610 Notogoneus Cope, 1885

611 (Fig. 8D)

612 1997: Teleost R, Eberth and Brinkman, p. 57

613 2002: Morphoseries IIIA-2, Brinkman and Neuman, p. 151, fig. 8.5–8.8

614 2019: Notogoneus, Brinkman, p. 126–129, fig. 10

615 2019: Notogoneus, Divay et al., p. 1–18, fig. 2–9.

616 Referred material: Hell Creek Formation: MOR 9393/HC-597, one centrum; MOR 9406/HC-

617 597, one centrum; MOR 9440/HC-656, one caudal centrum.

618 Description: Notogoneus is represented in the late Maastrichtian by centra from the Hell Creek

619 Formation (Fig. 8D). As in centra of Notogoneus from the Dinosaur Park Formation described by

620 Divay et al. (2019), the centra are subequal in length and width. The neural arches and

621 parapophyses are fused to the centrum. The neural arches are elongate and extend the full length

622 of the centrum. A narrow mid-dorsal ridge is present between the bases of the neural arch. The

623 parapophyses are located on the antero-ventral end of the centrum. A mid-ventral pit is present.

624 The Notogoneus centrum from the Hell DraftCreek Formation differs from most of those from the late

625 Campanian specimens in that multiple small ridges are present on the side of the centrum present

626 rather than a single bony strut.

627 Remarks: Notogoneus is one of the few genera of non-marine teleosts represented by articulated

628 specimens in both Paleogene and Upper Cretaceous beds (Grande and Grande, 1999). In

629 addition, it is well represented in the Upper Cretaceous Dinosaur Park Formation by isolated

630 elements from vertebrate microfossil localities (Divay et al., 2019). However, it has a patchy

631 distribution in the Belly River Group, being abundant in a series of fine-grained deposits in the

632 Onefour area of southern Alberta but rare outside this area (Divay et al., 2019). The

633 morphological differences regarding the lateral surface features of late Campanian and late

634 Maastrichtian specimens could be of taxonomic significance. However, they may also reflect

635 ontogenetic change, because Divay et al. (2019) had noticed that their smaller specimens, in

636 particular, tended to have a multitude of longitudinal ridges on the lateral surface. If these

637 differences signal taxonomic differences, these differences are probably at a low taxonomic

638 level.

639

640 Series OTOPHYSI Garstang, 1931 (sensu Rosen and Greenwood, 1970)

641 Gen et sp. indet type U3/BvD

642 (Fig. 9)

643 2013: Otophysi gen et sp. indet. type U3/BvD, Brinkman et al., p. 215–219, figs. 10.19A–C,

644 10.20A–C, 10.21A–C

645 2014: Otophysi, gen et sp. indet. Brinkman et al., p. 255–256, fig. 7A–D

646 2017a, Otophysi genus et sp. indet U-3/BvD, Brinkman et al., p. 30–33, figs. 16–17, 18B

647 2019: Otophysi genus et sp. indet U-3/BvD,Draft Brinkman, p. 129–131, fig. 12–13B

648 Referred material: Hell Creek Formation: UCMP 230603/V73087, one anterior Weberian

649 centrum (centrum type U3); UCMP 230604/V73087, one anterior Weberian centrum (centrum

650 type U3); UCMP 230678/V99220, one anterior Weberian centrum (centrum type U3); UWBM

651 98187/C1153, anterior Weberian centrum (type U3); UWBM 106486/C1153, (type U3); UCMP

652 191592/V99369, a third Weberian centrum (centrum type BvC); UCMP 230620/V73087, a third

653 Weberian centrum (centrum type BvC); UCMP 230621/V73087, a third Weberian centrum

654 (centrum type BvC); UCMP 230754/V77130, an abdominal centrum (centrum type BvD);

655 UWBM 98121/C1153, abdominal centra (centrum type BvD); UWBM 106487/C1153, an

656 abdominal centrum (centrum type BvD).

657 Lance Formation (Bushy Tailed Blowout locality): UALVP 58839, seven anterior

658 Weberian centra (centrum type U3); UALVP 58840, two possible fourth Weberian centra;

659 UALVP 58838, two abdominal centra (centrum type BvD).

660 Scollard Formation (KUA2 locality): TMP 2009.13.75, two anterior Weberian centrum

661 (centrum type U3); TMP 2009.13.225, one anterior Weberian centrum (centrum type U3); TMP

662 2020.60.9, anterior Weberian centrum (centrum type U3); TMP 2020.60.10, third Weberian

663 centrum (centrum type BvC).

664 Description: Anterior Weberian centra, initially described as centrum type U3 (Brinkman et al.

665 2013), are similar to specimens from the late Campanian described previously as being greatly

666 foreshortened, having a nearly flat anterior surface and a shallowly concave posterior surface

667 (Fig. 9A–B). The anterior surface is ovate in marginal outline whereas the posterior surface is

668 more evenly rounded. A pair of small circular pits separated by a rounded bar of bone about

669 equal in width to the diameter of the pits is present on the dorsal surface. Parapophyses are

670 represented by vertically oriented ridgesDraft that project ventro-laterally from approximately mid

671 height of the lateral surfaces of these centra. A distinctive feature of the U3 centrum type is the

672 presence of a large circular fossa on its ventral surface. The diameter of this fossa spans between

673 one-half to nearly the entire length of the centrum.

674 Third Weberian centra, which were initially referred to as centrum type BvC (Fig. 9C),

675 are present in Hell Creek and Scollard assemblages. The neural arch articular pits are large

676 circular openings located in the anterior half of the centrum. A depression is present on the side

677 of the centrum with an elongate groove leading to postero-dorsal processes. This groove was

678 interpreted as the articular surface for the tripus (the fourth Weberian ossicle) by Brinkman

679 (2019). An elongate mid-ventral pit is present.

680 Post-Weberian abdominal centra, which were initially referred to as centrum type BvD,

681 are low and wide (Fig. 9E). Neural arches are fused to the centrum and a deep mid-dorsal pit is

682 present between the neural arches. The ventral surface of the centrum is covered by a lacy

683 network formed by ridges of bone. A mid-ventral pit is present in some specimens (Fig. 9E) but

684 absent on others (Brinkman et al. 2014:fig. 7C–D). The variable development of this pit is

685 interpreted as a result of variation along the column, with the pit being most strongly developed

686 on centra from the anterior portion of the vertebral column. Parapophyses are autogenous and

687 large parapophyseal pits are present on the ventro-lateral sides of the centrum. These pits are

688 rectangular in shape and bordered by a sharp ridge dorsally (Fig. 9E).

689 One centrum from the Lance Formation appears similar to the abdominal centra but

690 distinct in that the centrum is medio-laterally narrow, the parapophyseal articular surfaces are

691 larger than that of the more posterior abdominal centra, a horizontal flange extends laterally

692 dorsal to the parapophyseal pit, and an elongate mid-ventral pit is present (Fig. 9D). This

693 centrum is tentatively identified as eitherDraft the anterior-most abdominal centrum or the fourth

694 Weberian centrum.

695 Remarks: Brinkman et al. (2013) concluded that two distinct centrum types that had been

696 designated centrum types U-3 and BvD were regional variants from the vertebral column of a

697 single kind of ostariophysan fish, which they referred to as Teleost indet. type U3/BvD. This fish

698 was included in the Otophysi by Brinkman et al. (2017) because they identified centrum type U3

699 as the anterior centrum of the Weberian apparatus. Brinkman et al. (2013, 2017) also referred

700 dentaries to teleost indet. type U3/BvD. These dentaries further supported the otophysan

701 relationships of teleost indet. type U3/BvD because they had similarities with those of catfishes

702 (Order Siluriformes). Brinkman (2017) described the third centrum of the Weberian apparatus,

703 providing further support for the presence of a Weberian apparatus in this taxon. Otophysi indet.

704 type U3/BvD is represented in the upper Maastrichtian formations studied here by both

705 Weberian and post-Weberian abdominal centra, including a previously undescribed centrum

706 morphotype that is tentatively identified as the fourth Weberian centrum or an anterior-most

707 post-Weberian abdominal centrum.

708 The otophysan relationships of teleost indet. type U3/BvD are strongly supported by the

709 evidence for a Weberian apparatus in this taxon. However, the position of U3/BvD within the

710 Otophysi is uncertain. Brinkman et al. (2014) suggested that it was a stem catfish based on

711 similarities in the dentary, particularly the arrangement of teeth. However, the catfish-like

712 features may be present in basal members of the Otophysi, so a stem position to this clade cannot

713 be ruled out. Furthermore, if the dentary has similarities with siluriform dentaries, centra, and

714 especially Weberian centra, are far more similar to cypriniform centra, further obscuring the

715 relationships of teleost indet. type U3/BvD within the Otophysi.

716 Centra of Otophysi indet. type U3/BvDDraft are present in all three upper Maastrichtian

717 formations studied here but are rare in most Hell Creek and Scollard localities (Table 2). The

718 higher abundance of this taxon in the Lance Formation agrees with the tendency for it to be more

719 abundant in southern localities during the Santonian and late Maastrichtian intervals (Brinkman

720 et al. 2013, 2017).

721

722 Subdivision EUTELEOSTEI sensu Arratia, 1999

723 Order SALMONIFORMES Bleeker, 1859 (sensu Greenwood et al., 1966)

724 Suborder ESOCIDAE Berg, 1936

725 Estesesox Wilson et al. 1992

726 (Fig. 10)

727 1964: Platacodon (in part), Estes, p. 51–53, fig. 26

728 1992: Estesesox foxi, Wilson et al, p. 819–846, figs. 2–3, 5, 7–8

729 1997: Teleost N, Eberth and Brinkman, p. 57

730 2001: Teleost indet. Peng, Russell, and Brinkman, p. 18, Plate 4, fig. 12–13

731 2002: Morphoseries IB-1, Brinkman and Neuman, p. 141–143, fig. 2-1 to 2-14

732 2005: Morphoseries IB-1, Neuman and Brinkman, p. 176, fig. 9.8B

733 2010: Esocoidea, Larson, Brinkman, and Bell, p. 1165, fig. 5C

734 2013: Salmoniform, Brinkman et al., p. 223–225, fig. 10.25

735 2014: Salmoniform, Brinkman et al., p. 257–259, fig. 9

736 2017a: Estesesox, Brinkman et al., p. 33–34, fig. 19

737 2019: Esocidae, Brinkman, p. 133–136, fig. 15–16

738 Referred material: Hell Creek Formation: UCMP 198885/V99369, three dentaries of

739 intermediate size; UCMP 230750/V77130,Draft dentary; UWBM 106050/C1917, dentary; UWBM

740 106542/C1529, dentary; MOR 9387/HC-597, dentary; UCMP 230608/V73087, centrum type

741 NvC; UCMP 230674/V99220, centrum type NvC; UWBM 98177/C1153, centrum type NvC;

742 UWBM 106454/C111, centrum type NvC; UWBM 106520/C1529, centrum type NvC; UWBM

743 106547/C1529, centrum type NvC; UWBM 106558/C1529, centrum type NvC; MOR 9346/HC-

744 597, centrum type NvC; MOR 9401/HC-597, centrum type NvC; MOR 9424/HC-656, centrum

745 type NvC; UWBM 106382/C1103, centrum types NvC and NvE; UWBM 106528/C1529,

746 centrum types NvC and NvE; UWBM 106582/C1153, centrum types NvC and NvE; MOR

747 9371/HC-597, centrum types NvC and NvE; MOR 9382/HC-597, centrum types NvC and NvE;

748 UCMP 191591/V99369, centra type NvD and NvE; UCMP 230606/V73087, centrum type NvD;

749 UWBM 98107/C1153, centrum type NvD; UWBM 106393/C1103, centrum type NvD; UWBM

750 106554/C1529, centrum type NvD; UCMP 230675/V99220, centrum type NvE; UWBM

751 98158/C1153, centrum type NvE; UWBM 106370/C1103, centrum type NvE; UWBM

752 106371/C1103, centrum type NvE; UWBM 106377/C1103, centrum type NvE; UWBM

753 106537/C1529, centrum type NvE; MOR 9341/HC-597, centrum type NvE; MOR 9349/HC-597,

754 centrum type NvE; MOR 9411/HC-597, centrum type NvE.

755 Lance Formation (Bushy Tailed Blowout locality): UALVP 58852, dentary; UALVP

756 58854, palatine; UALVP 58844, centrum type NvC.

757 Scollard Formation (KUA2 locality): TMP 2009.13.43, dentary; TMP 2009.13.172,

758 dentary; TMP 2009.13.177, dentary; TMP 2009.13.275, dentary; TMP 2009.13.302, dentary;

759 TMP 2009.13.344, dentary; TMP 2009.13.44, palatine; TMP 2009.13.343, palatine.

760 Description: Dentaries representing a range of sizes were recovered (Fig. 10A–F), all of which

761 have a long alveolar process, with a modest dorso-ventral expansion of the dentary in its

762 symphyseal and posterior parts, resultingDraft in the dorso-ventrally thinnest part of the dentary being

763 at approximately mid-length. A thin, essentially flat and featureless shelf extends on the medial

764 surface of the dentary, immediately ventral to the tooth bases, bordering a shallow Meckelian

765 groove. A low, wide, and blunt ridge of bone extends for the full length of the dentary along its

766 ventral margin, where two small foramina can be seen in the anterior half of the dentary. In

767 larger specimens (Fig 10A–B), a single row of large tooth bases is visible on the occlusal surface

768 of the dentary. In small specimens (Fig. 10E–F), a multitude of relatively smaller teeth are

769 instead visible on the occlusal surface, where they are arranged in several longitudinal tooth

770 rows. Specimens of intermediate size (Fig. 10C–D) show an intermediate condition, with

771 relatively smaller teeth than larger specimens arranged in relatively fewer longitudinal rows than

772 in smaller specimens.

773 The palatine (Fig. 10G) is an elongated bone with a relatively short anterior head,

774 expanding laterally into the widest point of the bone, and a long, gradually narrowing, posterior

775 part. The occlusal surface is covered by a multitude of tooth bases in no particular arrangement.

776 Tooth bases have a recognisably C-shaped pedestal anteriorly, for the depressible teeth

777 characteristic of esocids.

778 Abdominal centra (Fig. 10H–J) are spool-shaped, rounded in end view, with a central

779 notochordal foramen, autogenous neural arches and parapophyses. Anterior centra (Fig. 10H) are

780 relatively short, being approximately as long as they are wide, with progressively more posterior

781 positions becoming relatively much longer. Neural arch pits extend for most of the length of the

782 centrum on the dorsal surface, although more posterior positions have neural arch pits that

783 become progressively more limited to the anterior part of the dorsal surface of the centrum.

784 However, in all cases, these neural arch pits are bordered by simple ridges of bone.

785 Parapophyseal articular pits are similarlyDraft shaped, on the lateral to ventro-lateral surface of the

786 centrum. The pair of neural arch pits is separated from one another by a median dorsal pit that

787 encloses few, low, and transverse ridges in anterior vertebral positions (Fig. 10H). Neural arch

788 pits are separated from parapophyseal articular pits by simple ridges of bones in most vertebral

789 positions (Fig. 10 I–J), although in anterior positions (Fig. 10H), this separation is achieved by a

790 relatively wider and more textured bony strut. A thin median bony strut extends for the full

791 length of the centrum on the ventral surface of all vertebral positions. A pair of ventral accessory

792 pits are on either side of this bony strut, enclosing progressively more low, thin, transverse bony

793 struts in progressively more posterior vertebral positions.

794 Remarks: Esocids were first recognized in the Cretaceous by Wilson et al. (1992) who named

795 two taxa, Estesesox foxi and Oldmanesox canadensis, on the basis of dentaries that had been

796 previously referred to Platacodon by Estes (1964). Estesesox and Oldmanesox differed primarily

797 in that Estesesox had multiple tooth rows with smaller teeth, whereas Oldmanesox had a single

798 row of relatively large teeth, with the teeth more widely spaced. Estesesox foxi was reported

799 from both the late Campanian and the late Maastrichtian, but O. canadensis was restricted to the

800 late Campanian. Brinkman et al. (2014) recognized two additional taxa in the Hell Creek

801 Formation: Estesesox sp., which had fewer rows of teeth than E. foxi with the teeth being

802 relatively larger, and Oldmanesox sp., which had a single row of teeth. The specimens referred to

803 Oldmanesox sp. were similar to O. canadensis in having a single row of teeth but differed in that

804 they lacked the spacing between the teeth that were a characteristic feature of the type species.

805 With larger sample sizes of specimens of late Maastrichtian age, the three species recognized by

806 Brinkman et al. (2014; i.e., E. foxi, Estesesox sp., and Oldmanesox sp.) appear less distinct

807 because intermediate morphologies can be recognized. It now appears that the differences in the

808 esocid dentaries from the late MaastrichtianDraft are size-related, with smaller dentaries having

809 smaller teeth and a higher number of tooth rows (Fig. 10A–F). Thus, the variation in dental

810 morphology can be interpreted as a result of growth-related changes, and all three dentary

811 morphologies can be included in a single species of the genus Estesesox. With this revision to the

812 esocids of the late Maastrichtian Oldmanesox is represented by a single species that is restricted

813 to the late Campanian.

814 Wilson et al. (1992) recognized the presence of an unnamed esocid in the Hell Creek

815 Formation on the basis of palatines that were relatively more slender and bore fewer rows of

816 teeth than those from the late Campanian referred to Estesesox foxi (Wilson et al. 1992:figs. 2,

817 5). Narrow palatines with only two or three rows of teeth are also present in the Lance Formation

818 (Fig. 10G) and Scollard Formation. However, the possibility that the narrow palatines are from a

819 late Maastrichtian species of Estesesox and the late Maastrichtian and late Campanian species

820 differed in the morphology of the palatine cannot be eliminated.

821 Esocid centra from the Late Cretaceous were described by Brinkman and Neuman

822 (2002). These conformed to a generalized salmoniform pattern in being simple spools with

823 autogenous neural arches and parapophyses. They differed from centra of Esox in having a mid-

824 ventral ridge, rather than a groove or pit. Three morphotypes were recognized in the Hell Creek

825 Formation by Brinkman et al. (2014), which were designated NvC, NvD and NvE (Fig. 10 H–J).

826 These differed in the length of the neural arch pits, degree of separation of the neural arch and

827 parapophyseal pits, presence of postero-dorsal processes, and shape of the ventral space between

828 the parapophyseal pits (Brinkman et al. 2014:table 2). These were assumed to be taxonomically

829 distinct. However, a review of variation in centrum morphology in extant species of Esox (Sinha

830 et al. 2019) concluded that the differences were better interpreted as a result of variation along

831 the vertebral column of a single taxon. CentraDraft type NvC (Fig. 10H) are similar to anterior

832 abdominal centra of Esox in that the parapophyseal pits are more ventrally located. Centra type

833 NvD (Fig. 10J) are similar to posterior abdominal centra in that the neural arch articular surfaces

834 do not extend for the full length of the centra and postero-dorsal processes are present. Centra

835 type NvE (Fig. 10I) were interpreted as being from an intermediate position because the

836 parapophyseal pits are close to the neural arch articular pits as in NvD, but the neural arch pits

837 extend the full length of the centrum as in NvC. As well, the centra vary in relative length, NvC

838 being relatively shorter and NvD being relatively longer, mirroring the relative increase in length

839 of centra along the column in extant species of Esox.

840 Based on this reinterpretation of the significance of variation in dentaries and centra, a

841 single species of Estesesox is recognized in the late Maastrichtian, as originally proposed by

842 Wilson et al. (1992), However, given the possibility that the palatine of this species differs from

843 that of Estesesox foxi, the late Maastricthian taxon is considered to be an indeterminate species of

844 the genus.

845

846 Subdivision NEOTELEOSTEI sensu Arratia, 1999

847 Superorder ACANTHOMORPHA sensu Stiassny, 1986

848 Order PERCOPSIFORMES Berg, 1940

849 Gen. et sp. indet.

850 (Fig. 11A–B)

851 2005: Acanthomorph dentary, Neuman and Brinkman, p. 176, fig. 9.7E–G

852 2010: Acanthomorpha, Larson et al., p. 1167–1168, fig. 6H.

853 2013: Acanthomorpha gen et sp. indet., DraftBrinkman et al., p. 227, Fig. 10.28B

854 2014: Percopsiformes gen et sp. indet., Brinkman et al., p. 262, fig. 13

855 2019: Percopsiformes, Murray et al., p. 8, fig. 6

856 Referred material: Hell Creek Formation: UCMP 198875/V73087, dentary; UCMP

857 198884/V99369, two dentaries; UWBM 106544/C1529, dentary.

858 Lance Formation (Bushy Tailed Blowout locality): UALVP 59912, dentary.

859 Description: The occlusal surface of these small dentaries is occupied by a multitude of tooth

860 bases arranged in no particular pattern, forming a tooth patch that is widest in its anterior part

861 (Fig. 11A–B). The dentaries have a prominent ventral process, resulting in a sharply increasing

862 dorso-ventral width posteriorly. Below a projecting tooth shelf, the lingual surface is plain and

863 smooth, lacking texturing and foramina. The labial surface is likewise smooth, but bears a large

864 anterior foramen connecting to a wide, open lateral sensory canal extending along the ventral

865 margin of the dentary.

866 Remarks: Dentaries from the Hell Creek Formation were referred to the Percopsiformes by

867 Brinkman et al. (2014) because they are similar to extant members of the group in that the

868 sensory canal is open in lateral view along its length except for a narrow bridge that borders a

869 single circular pore located at the anterior end of the dentary (Fig. 11A). Also, the tooth-bearing

870 surface is broad and covered by a shagreen of tiny teeth. The bases for these teeth show little

871 variation in size across the tooth pad. The percopsiform relationships of this dentary morphotype

872 were confirmed by Murray et al. (2019), who described an articulated specimen of percopsiform

873 from the upper Maastrichtian Scollard Formation in which the dentaries were visible in lateral

874 view. A percopsiform dentary from the Lance Formation (Fig. 11B) differs from the Hell Creek

875 specimens (Fig. 11A) only in the smaller size of the pore at the end of the sensory canal.

876 Draft

877 Order PERCIFORMES Bleeker, 1859

878 Superorder ?MORONOIDEI Smith and Craig, 2007 (sensu Whitlock, 2010)

879 Family ?MORONIDAE Jordan, 1923 (sensu Whitlock, 2010)

880 ‘Priscacara’ sensu Cope, 1877

881 (Fig. 11C–D)

882 2014: Priscacara, Brinkman et al., p. 262, fig. 14

883 Referred material: Hell Creek Formation: UCMP 198873/V73087, dentary; UWBM

884 106543/C1529, dentary.

885 Scollard Formation (KUA2 locality): TMP 2009.13.167, dentary; TMP 2009.13.69,

886 dentary; TMP 2009.13.175, dentary; TMP 2015.37.56, dentary; TMP 2015.37.62, dentary.

887 Description: These small dentaries (Fig. 11C–D) are relatively longer than those ascribed to the

888 Percopsiformes above. A similar multitude of tiny tooth bases covers the occlusal surface in no

889 discernible arrangement, forming a tooth patch of consistent width along the length of the

890 dentary. The ventral process is prominent, increasing the dorso-ventral width of the dentary in its

891 posterior part, although this increase in width is more progressive than in the dentaries ascribed

892 to the Percopsiformes. The tooth shelf projects from the lingual surface similarly, but this surface

893 additionally has a foramen at approximately mid length of the tooth row, immediately ventral to

894 the tooth shelf. Contrasting with the percopsiform dentaries described above, the tooth shelf also

895 projects slightly from the labial surface, and the sensory canal is entirely enclosed in bone. Two

896 large foramina pierce this bony canal, exposing the sensory canal on the labial surface of the

897 dentary.

898 Remarks: Although a detailed discussion about the monophyly of the genus is beyond the scope

899 of this article, we acknowledge that ‘Priscacara’Draft has been considered a ‘form genus’ uniting

900 disparate fishes, rather than a natural group of related species (Grande 2001). The suggested

901 affinities of the fishes in the genus include with the Centropomidae (Cope, 1877), Cichlidae

902 (Woodward 1901; Haseman 1912; Hesse 1936), or Percichthyidae (Cavender, 1986), while

903 Jordan (1923) argued for the creation of the family Priscacaridae to accommodate the genus,

904 which has since been used by other authors (e.g., Wilson 1977; Grande 1984). We here

905 cautiously follow Whitlock’s (2010) placement of at least some of the fishes regrouped under

906 ‘Priscacara’ within the Moronidae primarily because of its relative recent publication. However,

907 most relevant to our purposes is that the inclusion of ‘Priscacara' in the Perciformes has been

908 universally accepted ever since its initial description (e.g., Cope 1877; Whitlock 2010),

909 regardless of the superorder and family affiliations of the fishes regrouped under ‘Priscacara’,

910 and of whether or not ‘Priscacara’ is a monophyletic genus.

911 Dentaries and tooth plates ascribed to ‘Priscacara’ were reported in the Hell Creek

912 Formation of Montana by Brinkman et al. (2014), on the basis of comparison with those of

913 articulated specimens of ‘Priscacara’ from the Green River Formation. Subsequently, isolated

914 dentaries and a ceratobranchial tooth plate of ‘Priscacara’ from the lower Eocene Wasatch

915 Formation were described by Divay and Murray (2016a), providing additional data on their

916 morphologies in this genus. Apart from their small size, ‘Priscacara’ dentaries from the late

917 Maastrichtian differ little from those from the Wasatch Formation, which informed our

918 attribution of these dentaries under this genus. However, the tooth plate referred to Priscacara by

919 Brinkman et al. (2014:fig.14D–E), is likely that of the sirenid salamander Habrosaurus. Thus,

920 although ‘Priscacara’ is currently represented in the late Maastrichtian by multiple dentaries

921 from the Hell Creek Formation, includingDraft one that is nearly complete (Fig. 11C), and a partial

922 ‘Priscacara’ dentary from the Scollard Formation (Fig. 11D), pharyngeal tooth plates are absent.

923 However, while ‘Priscacara’ serrata has robust pharyngeal jaws, ‘P.’ liops and ‘P.’ hypsacantha

924 do not (Grande 2001, Whitlock 2010), so the absence of tooth plates in the late Maastrichtian

925 material does not preclude ascribing it to this genus.

926

927 Order INDET.

928 Platacodon nanus Marsh, 1889

929 (Fig. 11E)

930 1889: Platacodon nanus, Marsh, p. 178

931 1900: Platacodon nanus, Hatcher, p. 719

932 1964: Platacodon nanus (in part), Estes, p. 51–53, fig. 25

933 Referred material: Hell Creek Formation: UCMP 198873/V73087, tooth plate; UCMP

934 198872/V73087, teeth; UWBM 94533/C1401, teeth; UWBM 100991/C1153, tooth; UWBM

935 106019/C1917, isolated tooth; UWBM 106048/C1103, isolated tooth; UWBM 100888/C1151,

936 elements not listed.

937 Lance Formation (Bushy Tailed Blowout locality): UALVP 58851, pharyngeal tooth

938 plate.

939 Scollard Formation (KUA2 locality): TMP 2020.60.11, isolated teeth.

940 Description: Platacodon is represented by triangular pharyngeal tooth plates with laterally

941 compressed teeth that have an apical cusp and a convex anterior border (Fig. 11E). These teeth

942 form a row on the posterior edge of the tooth plate, with the teeth decreasing in size away from

943 the mid-line. Draft

944 Remarks: Platacodon was originally described by Marsh (1889) on the basis of isolated teeth. It

945 was included in the perciform family Sciaenidae by Estes (1964), although this has been

946 questioned (Patterson 1993). Platacodon is present in all three upper Maastrichtian formations

947 studied here.

948

949 Acanthomorph centrum morphotypes

950 Acanthomorph centra have long been recognized as morphologically distinct. The first

951 centrum has a tripartite anterior articular surface with separate surfaces for contact with the

952 basioccipital and exoccipitals. The more posterior abdominal centra are distinctive in the

953 presence of zygapophyseal articulations between the centra and in that the ribs in the anterior

954 region of the vertebral column articulate on the lateral surface of the neural arch rather than

955 lower on the centrum (Rosen and Patterson 1969). Acanthomorph centra are abundant in all of

956 the upper Maastrichtian localities examined here and distinct morphotypes can be recognized

957 based primarily on the first abdominal centrum. Although the centrum morphotypes cannot be

958 associated with specific taxa represented by dentaries, they provide independent evidence

959 regarding the diversity and distribution of acanthomorphs during this time.

960

961 Superorder ACANTHOMORPHA sensu Stiassny, 1986

962 Order INDET.

963 Acanthomorph centrum type HC-1

964 (Fig. 12)

965 2014: Acanthomorph centrum type HC-1, Brinkman et al., p. 263–264, fig. 15C

966 Referred material: Hell Creek Formation:Draft UCMP 230601/V73087, five first abdominal centra;

967 UWBM 106381/C1103, one first centrum; UWBM 106546/C1529, three first and four

968 abdominal centra; UCMP 230591/V73087, four abdominal centra; UCMP 230599/V73087, two

969 abdominal centra; UWBM 106527/C1529, eight abdominal centra; UWBM 106553/C1529, one

970 abdominal centrum; UWBM 106560/C1529, one abdominal centrum; UWBM 106563/C1529,

971 four abdominal centra; UWBM 98195/C1153, centra; MOR 9429/HC-656, one abdominal

972 centrum; MOR 9432/HC-656, one abdominal centrum.

973 Lance Formation (Bushy Tailed Blowout locality): UALVP 58830, three first abdominal

974 centra; UALVP 58876, eighteen abdominal centra.

975 Scollard Formation (KUA2 locality): TMP 2009.13.5, abdominal centra; TMP

976 2009.13.76, one abdominal centrum; TMP 2009.13.351, ten abdominal centra; TMP

977 2015.37.102, three abdominal centra.

978 Description: Acanthomorph centrum type HC-1 was recognized by Brinkman et al. (2014) on

979 the basis of both first and more posterior abdominal centra from the Hell Creek Formation.

980 In the first abdominal centrum of type HC-1, the exoccipital articular surfaces do not

981 contact one another above the basioccipital articular surface and a network of ridges is present on

982 the dorsal surface of the centrum between the bases of the neural arch rather than a mid-dorsal

983 pit (Fig. 12A–B). The post-zygapophyses are particularly well developed, and the sides of the

984 centrum are formed by numerous ridges of bone that typically converge on the post-

985 zygapophyses. Mid-ventral pits are absent.

986 The more posterior abdominal centra of type HC-1 (Fig. 12C–E) share with the first

987 centrum the presence of a network of bony ridges dorsally between the neural arch bases. Also,

988 as with the first abdominal centrum, a mid-ventralDraft pit is absent or poorly developed. Rather, a

989 mid-ventral ridge (Fig. 12C–D), or a shallow groove may be present (Fig. 12E). Abdominal

990 centra of acanthomorph indet. type HC-1 from an anterior position on the column are short and

991 zygapophyses are particularly well developed (Fig. 12C). The abdominal centra from a more

992 posterior position are longer and have a distinctive pit marking the site of the articulation of the

993 rib on the side of the centrum (Fig. 12E). A similar pit is not seen in the corresponding centra of

994 acanthomorph indet. type HC-2, presumably because the rib articulated higher, on the neural

995 arch.

996 Remarks: The first abdominal centrum of acanthomorph centrum type HC-1 is similar to

997 Paleogene and Neogene centra identified as percopsiforms by Divay and Murray (2016a, 2015),

998 in their latero-anteriorly projecting articular facets for the exoccipitals, long overall length, and

999 fused neural arch bases. Centrum type HC-1 is especially reminiscent of some of the Eocene

1000 Wasatch Formation centra identified as aff. Amblyopsidae, by Divay and Murray (2016a) in the

1001 looser arrangement of the bony fibers forming the lateral and ventral surfaces of these centra.

1002 Thus, these centra may be from the same kind of fish as the percopsiform dentaries described

1003 above. First abdominal centra of type HC-1 are present in both the Lance and Hell Creek

1004 formations. Only abdominal centra of type HC-1 are present in the Scollard Formation.

1005

1006 Acanthomorph centrum type HC-2

1007 (Fig. 13 A–D)

1008 2014: Acanthomorph atlas centrum type HC-2, Brinkman et al., p. 263–264, fig. 15A

1009 Referred material: Hell Creek Formation: UCMP 297015/V99369, one first centrum; UWBM

1010 106572/C1917, one first centrum; MOR 9366/HC-597, one first centrum; MOR 9389/HC-597,

1011 two first centra; UWBM 106362/C1103,Draft one first and one abdominal centra; MOR 9370/HC-

1012 597, one first and two abdominal centra; MOR 9399/HC-597, one first and one abdominal

1013 centra; UCMP 230593/V73087, abdominal centra; UCMP 230665/V99220, abdominal centra;

1014 UWBM 98154/C1153, abdominal centra; UWBM 106392/C1103, two abdominal centra;

1015 UWBM 106490/C1153, one abdominal centrum; MOR 9381/HC-597, one abdominal centrum;

1016 MOR 9410/HC-597, one abdominal centrum; MOR 9415/HC-597, one abdominal centrum.

1017 Lance Formation (Bushy Tailed Blowout locality): UALVP 58832, six first abdominal

1018 centra; UALVP 58831, fourteen abdominal centra.

1019 Scollard Formation (KUA2 locality): TMP 2015.37.26, one abdominal centrum; TMP

1020 2009.13.347, two abdominal centra; TMP 2009.13.349, one first abdominal centrum.

1021 Description: Acanthomorph centrum type HC-2 was defined by Brinkman et al. (2013) on the

1022 basis of a first centrum morphotype from the Hell Creek Formation. The first abdominal centrum

1023 of type HC-2 differs from type HC-1 in that the exoccipital articular surfaces contact one another

1024 above the basioccipital articular surface and a mid-dorsal pit is present (Fig. 13A–B versus 12A–

1025 B). The sides of the centrum are formed by a relatively coarse network of bony ridges. A mid-

1026 ventral pit is typically present, bordered by enlarged bony ridges.

1027 More posterior abdominal centra referred to type HC-2 share with the first centrum the

1028 presence of a mid-dorsal and a mid-ventral pit, with the mid-ventral pit generally bordered by

1029 distinct ridges (Fig. 13C–D). This is in contrast with the abdominal centra of acanthomorph

1030 indet. type HC-1, which have a network of bony ridges between the neural arch bases of the

1031 abdominal centra (Fig. 12C–D). Also, as with the first centrum, the sides of the centra are formed

1032 by relatively few ridges that form a loose network, with larger ridges extending between the ends

1033 of the centrum and smaller ridges connecting these.

1034 Remarks: Acanthomorph centrum typeDraft HC-2 is a generalized morphotype that is widely

1035 distributed in the Western Interior of North America during the Late Cretaceous. Centra of this

1036 morphotype are abundant in all three upper Maastrichtian formations that were examined (Table

1037 2). Similar morphologies have been recovered from North American Cenozoic formations,

1038 including the Eocene Wasatch Formation, where similar centra were attributed by Divay and

1039 Murray (2016a) to aff. Centrarchidae and ‘Priscacara’. However, centrum type HC-2 is different

1040 from these Cenozoic taxa in lacking the well-defined, rounded dorsal articular pits for the neural

1041 arches, which are very distinctive in Paleogene specimens (Divay and Murray 2016a:fig. 7C–D;

1042 fig. 9A). Therefore, centrum type HC-2 represents an acanthomorph of uncertain affinities, but

1043 most likely an archaic perciform taxon.

1044

1045 Acanthomorph centrum type HC-3

1046 (Fig. 14 A–B)

1047 Referred material: Hell Creek Formation: UCMP297016/V99369, two first abdominal centra.

1048 Lance Formation (Bushy Tailed Blowout locality): UALVP 58833, seven first

1049 abdominal centra.

1050 Description: Acanthomorph centrum type HC-3 is a previously unrecognized morphotype

1051 represented only by first abdominal centra. It is like type HC-1 in that the exoccipital articular

1052 surfaces do not contact (Fig 14B) or barely contact (Fig. 14A) one another above the

1053 basioccipital articular surface and in that a distinct mid-ventral pit is absent. It differs from type

1054 HC-1 and is similar to type HC-2 in that a mid-dorsal pit is present. The proportions of the first

1055 abdominal centrum of type HC-3 are similar to those of HC-2 in being about as wide as they are

1056 long, in contrast with the elongate first abdominal centra of type HC-1.

1057 Remarks: In the absence of a broad contactDraft between the exoccipital articular surface, presence

1058 of a mid-dorsal pit, and absence of a mid-ventral pit, acanthomorph centrum type HC-3 is similar

1059 to the centrum morphotype from the Belly River Group described as type AvC by Brinkman

1060 (2019:fig. 18A–B). These two morphotypes differ in that type HC-3 lacks a distinct, rounded,

1061 smooth area on the side of the centrum. Acanthomorph centrum type HC-3 was only observed in

1062 the Lance and Hell Creek formations.

1063

1064 Acanthomorph centrum type HC-4

1065 (Fig. 15)

1066 2014: Acanthomorph centrum type HC-4, Brinkman et al., p. 264, fig. 15E

1067 Referred material: Hell Creek Formation: centra; UCMP 191553/V99227, abdominal centra;

1068 UWBM 98131/C1153, abdominal centra; UWBM 106369(in part)/C1103, one abdominal

1069 centrum; MOR 9340(in part)/HC-597, one abdominal centrum; MOR 9345/HC-597, one

1070 abdominal centrum.

1071 Lance Formation (Bushy Tailed Blowout locality): UALVP 58836, one first abdominal

1072 centrum; UALVP 58834, seven abdominal centra.

1073 Description: Acanthomorph centrum type HC-4 was recognized by Brinkman et al. (2014) on

1074 the basis of abdominal centra that had a single well-developed mid-dorsal ridge extending

1075 between the ends of the centrum. First abdominal centra were not recognized by Brinkman et al.

1076 (2014), although a distinctive centrum with a broad mid-dorsal ridge from the Lance Formation

1077 is tentatively identified as this element (Fig. 15A). This first abdominal centrum also differs from

1078 the first abdominal centrum of type HC-2 in that the exoccipital articular surfaces have only a

1079 slight contact at the midline, are set backDraft from the anterior edge of the centrum, and barely

1080 extend laterally from the lateral sides of the centrum. The ventral surface of the centrum is

1081 formed of multiple ridges that coalesce to form a relatively solid surface. Abdominal centra are

1082 characterized by a single straight mid-dorsal ridge separating two elongate depressions (Fig.

1083 15B–D). The ventral surface of the centrum may be formed by a network of ridges (Fig. 15B) or

1084 a mid-ventral pit bordered by elongate ridges may be present (Fig. 15C–D). This variation likely

1085 reflects different positions along the vertebral column.

1086 Remarks: Acanthomorph centrum type HC-4 is present in the Hell Creek and Lance formations.

1087 This is a distinctive morphology that has not been recovered in any North American Paleogene

1088 localities that we are aware of, and may therefore represent an archaic group of acanthomorphs

1089 restricted to the Late Cretaceous.

1090

1091 Acanthomorph centrum type HC-5

1092 (Fig. 16)

1093 Referred material: Hell Creek: UCMP 230597/V73087, first abdominal centrum; MOR

1094 9289/HC-597, first abdominal centrum; MOR 9366/HC-597, first abdominal centrum.

1095 Bug Creek Anthills locality: ROM 59156, first abdominal centrum; ROM 59157, anterior

1096 abdominal centrum; ROM 59158, mid abdominal centrum; ROM 59159, posterior abdominal

1097 centrum.

1098 Lance (Bushy Tailed Blowout locality): UALVP 58829, first abdominal centrum.

1099 Scollard (KUA-2 locality): TMP 2009.13.72, one first abdominal centrum.

1100 Description: Acanthomorph centrum type HC-5 is a previously unrecognized centrum

1101 morphotype represented by both the firstDraft and more posterior abdominal centra. The first

1102 abdominal centrum (Fig. 16A–B) is similar to the first abdominal centrum of acanthomorph

1103 centrum type HC-2 in that the exoccipital articular surfaces meet above the anterior articular

1104 surface and a deep mid-dorsal pit is present between the bases of the neural arch. It differs in

1105 being distinctly shorter antero-posteriorly, in that the ventral surface of the centrum is formed by

1106 numerous thin ridges of bone extending between the ends of the centrum, and in lacking a

1107 distinct mid-ventral pit.

1108 Abdominal centra included in acanthomorph centrum type HC-5 (Fig. 16 C–E) share

1109 with the first abdominal centrum the presence of numerous fibers of bone extending between the

1110 ends of the centrum and a weakly developed or absent mid-ventral pit. The ridges bordering the

1111 mid-ventral pit, when present, are not significantly more robust than those on the lateral surface

1112 of the centrum (Fig. 16D). The length of these abdominal centra varies, with the more anterior

1113 centra being similar to the first abdominal centrum in being very short (Fig. 16B–C), and the

1114 more posterior abdominal centra being about as long as they are wide (Fig. 16E).

1115 Remarks: Centrum morphotype HC-5 is similar to HC-2 but differs in being shorter and lacking

1116 a mid-ventral pit. It is rare, but present in both the Lance and Hell Creek formations. This

1117 morphology is reminiscent of several North American Cenozoic perciforms, including Paleogene

1118 taxa such as ‘Priscacara’, and some centra attributed to aff. Centrarchidae by Divay and Murray

1119 (2015, 2016a). However, this morphology is quite generic, and is also similar to other North

1120 American taxa more common in the Neogene, such as the Moronidae and the Percidae (Divay

1121 and Murray 2015, 2013), although these derived perciforms tend to have very distinctive, well-

1122 defined, and rounded articular pits for the neural arches on their first centra, which morphotype

1123 HC-5 seems to lack. Therefore, the affinitiesDraft of the acanthomorph represented by centrum type

1124 HC-5 remain unresolved at this time, but it is likely to be an archaic perciform.

1125

1126 Acanthomorph centrum type HC-6

1127 (Fig. 17)

1128 2014: Acanthomorph centrum type HC-1, Brinkman et al., p. 264, fig. 15F

1129 Referred material: Hell Creek Formation: UCMP 198876/V73087, one abdominal centrum;

1130 UWBM 98182/C1153, abdominal centra.

1131 Bug Creek Anthills locality: ROM 59160, one abdominal centrum.

1132 Lance Formation (Bushy Tailed Blowout locality): UALVP 58847, one abdominal

1133 centrum.

1134 Description: Acanthomorph centrum type HC-6 was recognized by Brinkman et al. (2014) on

1135 the basis of large abdominal centra with their sides and ventral surface being covered by a lacy

1136 network of bone, rather than distinct ridges. In dorsal view, a mid-dorsal ridge subdivides a small

1137 mid-dorsal pit (Fig. 17). Laterally, a pit is present just below the base of the neural arch. This pit

1138 is more strongly developed in the more posterior centra (e.g. Fig. 17C). Ventrally, a mid-ventral

1139 pit is present. In anterior view the centrum is round to dorso-ventrally compressed. Antero-

1140 ventral processes are present, with these being more strongly developed in the more anterior

1141 centra (e.g. Fig. 17A).

1142 Remarks: Centrum type HC-6 is present in both the Lance and Hell Creek formations but is

1143 rare. Acanthomorph affinities are indicated by the presence of zygapophyseal articular surfaces

1144 on the posterior end of the centrum. Type HC-6 is the largest acanthomorph, and one of the

1145 largest teleost fishes, in the upper Maastrichtian formations that were studied here.

1146 Acanthomorph centra with a similar lacyDraft surface texture were not observed in Campanian

1147 assemblages (Brinkman 2019; Brinkman et al. 2013). This morphotype is similar to Mioplosus in

1148 some respects, including in the dorso-ventral compression of the centrum, the long neural arch

1149 bases extending for its full length, the lateral pit adjacent to these neural arch bases, in the large

1150 ventral pit, and in the large overall size of these centra. However, Mioplosus has not been found

1151 to have prominent antero-ventral processes, does not have a lacy surface texture on the lateral

1152 and ventral surfaces of the centra, and only has the low, longitudinal subdivision of the median

1153 dorsal pit in the first vertebral position (Divay and Murray, 2015). The taxonomic affinities of

1154 Mioplosus are unclear themselves, beyond it being a perciform genus. Bruner (2011) excludes it

1155 from the Percidae without grouping it with any other family, while other authors have proposed

1156 affinities to the Percidae (e.g., Cope, 1877; Woodward, 1901; Grande, 1984), the Percichthyidae

1157 (Cavender, 1986), or the Moronoidei, as a relative of latids (Whitlock, 2010). Therefore, the

1158 taxonomic affinities of the acanthomorph represented by centrum type HC-6 remain unclear, but

1159 it may be allied to the Paleocene to Eocene-Oligocene genus Mioplosus.

1160

1161

1162 Teleost fishes of uncertain affiliations

1163 As in Late Cretaceous vertebrate microfossil assemblages from elsewhere within the

1164 Western Interior, centra are present that are taxonomically distinct but cannot be identified below

1165 the level of Teleostei. Despite their uncertain taxonomic affiliations, they help characterize the

1166 vertebrate assemblages preserved at the individual vertebrate microfossil localities and the

1167 geographic and stratigraphic distribution patterns that are present. These morphotypes are treated

1168 as distinct operational taxonomic units. Draft

1169

1170 Gen. et sp. indet. type U-4

1171 (Fig. 18)

1172 2013: Genus et sp. indet. type U-4, Brinkman et al., p. 221, fig. 20.23

1173 2014: Genus and species indet. U-4, Brinkman et al., p. 259–260, fig. 10A–B

1174 2019: Teleost centrum morphotype U-4, Brinkman, p 145, fig. 23

1175 Referred material: Hell Creek Formation: UCMP 297017/V99369, one abdominal centrum;

1176 UCMP 230626/V73087, one abdominal centrum; UCMP 230627/V73087, one abdominal

1177 centrum; UCMP 230628/V73087, two abdominal centra; UWBM 98189/C1153, abdominal

1178 centra ; UWBM 106484/C1153, one abdominal centrum; UWBM 106523/C1529, three

1179 abdominal centra; UWBM 106530/C1529, one abdominal centrum; UWBM 106538/C1529, two

1180 abdominal centra; UWBM 106564/C1529, one abdominal centrum; UWBM 106567/C1917, one

1181 abdominal centrum; UWBM 106574/C1917, one abdominal centrum; MOR 9417/HC-656, one

1182 abdominal centrum; MOR 9421/HC-656, one abdominal centrum.

1183 Lance Formation (Bushy Tailed Blowout locality): UALVP 58847, abdominal centra.

1184 Scollard Formation (KUA2 locality): TMP 2009.13.71, one abdominal centrum; TMP

1185 2015.37.74, two abdominal centra; TMP 2009.13.350, six centra.

1186 Description: Teleost genus and species indet. type U-4 was recognized by Brinkman et al.

1187 (2013) on the basis of centra that are small, simple spools with deep neural arch and

1188 parapophyseal pits and a shallowly excavated to nearly flat anterior surface (Fig. 18). Centra are

1189 wider than high and tend to appear sub-rectangular in anterior view. Neural arch articular pits are

1190 generally widely spaced. In some specimens, these pits are separated by a solid bar of bone (Fig.

1191 18A), whereas in others, well defined mid-dorsalDraft pits are present (Fig. 18B–D). Parapophyseal

1192 pits are large, oval pits about equal in size to the neural arch articular pits. A small mid-ventral

1193 pit is generally present.

1194 Remarks: Teleost centrum type U-4 is widespread in the Cretaceous, occurring in the

1195 Cenomanian to Campanian of Utah (Brinkman et al. 2013), the Santonian to late Campanian of

1196 Alberta (Brinkman et al. 2017), and all three upper Maastrichtian formations examined here

1197 (Brinkman et al. 2014). The relationships of teleost genus and species indet. U-4 are unknown.

1198

1199 Gen. et sp. indet. type RvB

1200 (Fig. 19)

1201 Referred material: Hell Creek Formation: UWBM 103821/C1103, one abdominal centrum;

1202 UWBM 106400/C1103, one abdominal centrum; MOR 9348/HC-597, one abdominal centrum;

1203 MOR 9361/HC-597, one abdominal centrum.

1204 Bug Creek Anthills locality: UCMP 198879/V65127, two abdominal centra; ROM

1205 59133, one abdominal centrum.

1206 Lance Formation (Bushy Tailed Blowout locality): UALVP 58848, one abdominal

1207 centrum.

1208 Description: Centra of genus and species indet. type RvB are large, reaching 3 centimeters in

1209 length. The neural arch and parapophyses are fused to the centrum. Both neural arches and

1210 parapophyses are elongate, extending the full length of the centrum. The space between the bases

1211 of the neural arch is flat in contrast to centra of Notogoneus, which have a narrow mid-dorsal

1212 ridge in this region. The parapophyses are flange-like, horizontally oriented processes that extend

1213 laterally from the centrum. The surface of the centrum between the base of the neural arch and

1214 parapophyses lacks distinct ridges or pits.Draft Ventral to the parapophyses, the centrum is

1215 compressed to form a moderately broad (Fig. 19A) to narrow (Fig. 19B) bar extending between

1216 the ends of the centrum. The length of the centrum varies, likely reflecting position along the

1217 column.

1218 Remarks: Genus and species indet. type RvB is a previously unrecognized teleost represented

1219 by centra. These are present in both the Lance and Hell Creek formations (Fig. 19 D–E), but the

1220 best-preserved specimens are from the Bug Creek Anthills locality (Fig. 19 A–C), and the

1221 description above is based primarily on specimens from this locality.

1222 Specimens from the Lance and Hell Creek formations (Fig. 19D–E) are included in

1223 teleost indet. type RvB because they have elongated neural arch bases without a mid-dorsal ridge

1224 and elongate, blade-like parapophyses. They are smaller than the Bug Creek Anthills specimens

1225 and likely from a posterior position along the column because the parapophyses are located in a

1226 ventral position and directed ventrolaterally.

1227 Genus and species indet. type RvB is present in both the Hell Creek and Lance

1228 formations, but is rare. It is the largest non-marine teleost fish in the upper Maastrichtian

1229 formations that were studied here. Its relationships are unknown.

1230

1231 Discussion

1232 Teleost diversity during the late Maastrichtian: A recent study of Hell Creek Formation fishes

1233 from many of the same vertebrate microfossil localities studied here (Brinkman et al. 2014)

1234 demonstrated that teleosts were more diverse than previously recognized. The additional samples

1235 subsequently collected by UWBM paleontologists (GPWM and DGD), and the inclusion of

1236 samples from other upper Maastrichtian formations gives a more complete understanding of the

1237 diversity and distribution of teleosts duringDraft this time. Tooth-bearing elements and abdominal

1238 centra both provide information on teleost diversity. Although these elements can be directly

1239 associated in only a few cases, together they provide an understanding of the diversity of teleosts

1240 of the late Maastrichtian in the northern Western Interior of North America.

1241 Based on tooth-bearing elements, 11 taxa can be recognized from the late Maastrichtian

1242 of the northern Western Interior of North America. These include one elopomorph, six

1243 osteoglossomorphs, one esocid, and three acanthomorphs (Table 1). Brinkman et al. (2014)

1244 recognized only two different osteoglossomorph tooth-bearing elements, namely Wilsonichthys

1245 ardinsulensis and Wilsonichthys sp. Two species of Coriops were recognized on the basis of

1246 centra but no tooth-bearing elements were available at the time of that study. The basibranchial

1247 elements described here confirm the presence of two closely related species of this genus. In

1248 addition, the diversity of osteoglossomorphs of the late Maastrichtian is increased by the

1249 presence of two taxa that are not yet known from the Hell Creek Formation, aff. Lopadichthys

1250 and Ostariostoma. In the recognition of a single kind of esocid in the assemblage, the diversity of

1251 esocids recognized here is less than that recognized by Brinkman et al. (2014), who recognized

1252 three kinds. This difference is because the morphological differences in the tooth row are here

1253 reinterpreted as growth stages in a single ontogenetic sequence.

1254 Based on a sample of 1911 precaudal centra, we recognize 19 taxa from the late

1255 Maastrichtian of the northern Western Interior of North America: one elopiform, six

1256 osteoglossomorphs, three ostariophysans, one esocid, six acanthomorphs, and two teleosts of

1257 uncertain affiliations (Table 2). The elopiform is rare, being represented by a single centrum

1258 from the Lance Formation. Because this centrum is clearly distinct from those of albuloids, it

1259 cannot be referred to Phyllodus, which is represented only by teeth, so a minimum of two

1260 elopomorphs would have been present duringDraft the late Maastrichtian.

1261 Tooth-bearing elements and centra both indicate the presence of six taxa of

1262 osteoglossomorphs, although a one-to-one correspondence between the centra and tooth-bearing

1263 elements is unlikely. In particular, it is possible that the dentary referred to Ostariostoma is

1264 associated with the centra referred to Teleost indet. type H, and that this taxon is a

1265 gonorynchiform rather than an osteoglossomorph. Thus, to minimize an inflation of the diversity

1266 present, only taxa based on centrum morphotypes are used in estimating the number of

1267 osteoglossomorphs present.

1268 The diversity of ostariophysans in the Hell Creek Formation is increased by the

1269 recognition of the presence of Notogoneus and that a previously indeterminate teleost referred to

1270 as teleost indet. type H is a gonorynchiform. Notogoneus is rare (only five centra; Table 2), so its

1271 recognition here is likely a result of the increased sample size available for study.

1272 A single esocid is recognized here because the three centrum morphotypes that were

1273 previously considered taxonomically distinct (i.e., NvC, NvD, NvE; Brinkman et al. 2014) were

1274 reinterpreted as differing because of variation along the vertebral column of a single taxon by

1275 Sinha et al. (2019). Here we refer these morphotypes collectively to Estesesox.

1276 The diversity of acanthomorphs represented by centra is increased from four to six

1277 operational taxonomic units because of the recognition of two additional morphotypes (i.e.,

1278 acanthomorph indet. types HC-3 and HC-5). Both are present in the Hell Creek Formation of

1279 Garfield County but are relatively rare in that unit (two and 15 centra, respectively; Table 2) and

1280 are more fully documented by specimens from other formations and localities. Acanthomorph

1281 indet. type HC-3 is best represented by specimens from the Lance Formation, whereas

1282 acanthomorph indet. type HC-5 is most Draftfully documented by more than ten specimens from the

1283 Bug Creek Anthills locality.

1284 Centra indicate the presence of two taxa of uncertain relationships. One of these, teleost

1285 indet. type U4, is widely distributed both temporally (Cenomanian–Maastrichtian) and

1286 paleobiogeographically (Utah to Alberta) during the Late Cretaceous (e.g., Brinkman et al.

1287 2013:table 10.3) and was first recognized in the Hell Creek Formation by Brinkman et al. (2014).

1288 The second, teleost indet. type RvB, was not previously recognized in the Hell Creek. As with

1289 the elopiform and Notogoneus, it is rare (only four centra; Table 2), so its recognition here is

1290 likely a result of the increased sample size available for study.

1291 In summary, centra, which indicate the presence of 19 kinds of teleosts in the late

1292 Maastrichtian, provide a fuller understanding of the diversity of teleosts during this time than do

1293 tooth-bearing elements. However, at least one teleost, Phyllodus, is represented by tooth-bearing

1294 elements but not centra. Combined, tooth-bearing elements and centra indicate the presence of at

1295 least 20 kinds of teleosts during this time.

1296

1297 Teleost turnover during the Late Cretaceous: Studies of teleost assemblages from vertebrate

1298 microfossil localities spanning the Late Cretaceous of North America (Neuman and Brinkman

1299 2005; Brinkman et al. 2013, 2014; 2017; Brinkman 2019) have documented a general increase in

1300 diversity punctuated by two periods of major taxonomic turnover, one in the late Turonian and

1301 one between the late Santonian and the late Campanian. Likewise, a comparison of the teleosts

1302 of the late Campanian with those of the late Maastrichtian described here also documents

1303 significant changes during this time. Teleost assemblages of the late Campanian are best known

1304 from the Belly River Group of Alberta (BrinkmanDraft 2019). With 26 operational taxonomic units

1305 recognized from this unit on the basis of centra, the diversity of non-marine teleosts of the late

1306 Campanian is estimated to be greater than that of the late Maastrichtian. This difference is

1307 primarily a result of the presence of four kinds of clupeomorphs and three kinds of teleosts of

1308 uncertain affiliations known only in the Belly River Group assemblage, which are different from

1309 the unidentified teleosts we document here from the late Maastrichtian. Because clupeomorphs

1310 tend to have a patchy geographic distribution in the late Campanian, and at least two of the taxa

1311 present in the late Campanian are members of groups present in the Paleogene

1312 (Ellimmichthyiformes and Clupeiformes), their absence in the late Maastrichtian can probably be

1313 attributed to local environmental conditions.

1314 Considered within the context of the later history of the group, a major difference

1315 between the late Campanian and late Maastrichtian teleost assemblages is seen in the kinds of

1316 acanthomorphs present. In the late Campanian, all the acanthomorphs represented by dentaries

1317 can be included in the Percopsiformes. The late Maastrichtian assemblages differ in the presence

1318 of two additional acanthomorphs, ‘Priscacara’ and Platacodon, at least one of which,

1319 ‘Priscacara’, can be included in the Perciformes, regardless of whether or not the genus is

1320 monophyletic (Grande 2001). This provides documentation that the group originated during the

1321 Late Cretaceous and prior to the K/Pg mass extinction event.

1322 Brinkman et al. (2014) also recognized that assemblages of teleost fossils from the upper

1323 Maastrichtian formations differed from those of the upper Campanian in that centra of

1324 acanthomorphs are more abundant relative to those of other teleosts, and this abundance

1325 increased up-section within the Hell Creek Formation (Brinkman et al. 2014:fig. 17). This

1326 pattern of increased abundance of acanthomorphs within the Hell Creek Formation, which is

1327 driven largely by the acanthomorph indet.Draft types HC-1 and HC-2, is supported by the additional

1328 specimens and localities sampled here (Table 2, Fig. 20). In localities of the upper third of the

1329 Hell Creek Formation, acanthomorph centra constitute between 41% and 64% of all teleost

1330 centra. This contrasts with an abundance of between 12% and 26% in the lower third of the

1331 formation. In a sample from the middle third of the unit, UWBM locality C1153, the abundance

1332 of acanthomorphs, 31%, is intermediate between that of the upper and lower intervals. The

1333 abundance of acanthomorph centra in the Lance and Scollard formations is within the range seen

1334 in the lower and middle parts of the Hell Creek Formation (i.e., 25% and 30%, respectively),

1335 suggesting that this pattern may be visible throughout the Western Interior generally during the

1336 late Maastrichtian.

1337 Changes in the relative abundances of some of the other more abundant teleosts in the

1338 Hell Creek Formation also is recorded here (Fig. 20). Although to a lesser degree than that

1339 observed among the acanthomorphs, teleost indet. type U4 similarly increased in relative

1340 abundance up-section from <2% in the lower part of the Hell Creek Formation to ~15% in the

1341 uppermost part. Conversely, Coriops/Lopadichthys dropped in abundance from as much as 59%

1342 in the lower Hell Creek to as little as 3% immediately below the K/Pg boundary. The

1343 wilsonichthyids maintained a somewhat steady abundance through the formation, with values

1344 hovering mostly between about 10% and 30%. The esocids revealed a pattern of increased to

1345 decreased relative abundances leading up to the K/Pg boundary, with their greatest abundance in

1346 the middle of the formation (26%).

1347 Similar concurrent increases and/or decreases in the relative abundances of other

1348 vertebrate taxa through the Hell Creek Formation of Garfield County, Montana have been

1349 documented. These include: i) opposing changes in the relative abundances of hybodont and

1350 orectolobiform sharks (increased) versusDraft the rhinobatoid Myledaphus pustulosus (decreased)

1351 among euselachians (Wynd et al. 2020:fig. 10); ii) Opisthotriton kayi significantly increased up-

1352 section whereas Scapherpeton tectum decreased among caudates (Wilson et al. 2014:fig. 10);

1353 and, iii) increased abundances of Triceratops relative to other dinosaurs on the basis of skeletal

1354 assemblages (Horner et al. 2011:fig. 2). For mammals, metatherians show a significant decline in

1355 their relative abundances across this stratigraphic interval (Wilson 2014:fig. 9). Similarly, results

1356 from these studies and those on anurans (Mercier et al. 2014), squamates (DeMar 2016), and

1357 testudines (Holroyd et al. 2014) all reveal a pattern of taxonomic turnover between the lower and

1358 upper Hell Creek assemblages. Ongoing and future studies using these complementary datasets

1359 (e.g., DeMar et al. 2016), including the results from this study, will form the basis for a more

1360 taxonomically inclusive community-level study of these faunas leading up to and across the

1361 K/Pg boundary.

1362

1363 Teleost turnover during the early Paleogene: Remains of teleosts from the upper Maastrichtian

1364 vertebrate microfossil localities provide data on the diversity and distribution of the group

1365 leading up to and immediately prior to the K/Pg mass extinction event. Currently, the diversity of

1366 teleosts from the lower Paleocene formations have not been fully described, so details of the

1367 pattern of survival and extinction immediately across the boundary are poorly known. However,

1368 a general picture of the faunal changes that occurred during the early Paleocene can be obtained

1369 by comparison with late Paleocene and early Eocene teleost assemblages. Late Paleocene

1370 teleosts are best known from the Paskapoo Formation of Alberta, Canada (Fig. 1). Teleosts from

1371 this formation that are represented by articulated specimens include: i) the osteoglossomorphs

1372 Joffrichthys symmetropterus, J. tanyourus, and Lopadichthys lindoei (Li and Wilson 1996;

1373 Murray et al. 2018); ii) the esocid Esox Drafttiemanni (Wilson 1980); iii) the smelt Speirsaenigma

1374 lindoei (Wilson and Williams 1991); and, iv) the percopsiforms Massamorichthys wilsoni and

1375 Lateopisciculus turrifumosus (Murray 1996; Murray and Wilson 1996). In addition to these

1376 seven taxa, isolated elements were referred to the Hiodontidae, Cyprinoidea, Gonorynchidae, and

1377 Asineopsidae by Wilson (1980), although the specimen identified as hiodontid was later referred

1378 to Joffrichthys (Li and Wilson 1996). Reports of teleost fossils of Paleocene age outside Alberta

1379 include a species of Joffrichthys from North Dakota, USA (Newbrey and Bozek 2000), and a

1380 percopsiform from the Early Paleocene of Montana, Mcconichthys (Grande 1988). Early Eocene

1381 assemblages from the Green River Formation provide an unparalleled picture of lacustrine

1382 assemblages of this time (Grande 2013). The Early Eocene Bitter Creek locality of the Wasatch

1383 Formation, Wyoming (Fig. 1), which, like the Cretaceous localities, contains a mixture of

1384 isolated elements of terrestrial and aquatic animals that accumulated as a result of fluvial

1385 activity, provides data on a fluvial assemblage that is taphonomically similar to the teleost

1386 assemblages from the upper Maastrichtian formations described here. Together, this material

1387 indicates that teleosts of the late Paleocene had their origin during the Cretaceous because all

1388 except the smelt and the cyprinoid are members of higher-level taxa that are present in the late

1389 Maastrichtian. This is consistent with Cavin’s (2002) observation that most of the families of

1390 bony fishes with freshwater representatives during the Late Cretaceous crossed the K/Pg

1391 boundary.

1392 That the K/Pg mass extinction did not significantly affect higher taxonomic groups of

1393 teleosts is further evidenced by the presence of most of the fish orders we here document from

1394 the Maastrichtian in the Eocene Green River Formation, albeit mostly represented by different

1395 genera. According to Grande (1984, 2001, 2013), the Green River Formation preserves

1396 hiodontiform, osteoglossiform, gonorynchiform,Draft esociform, percopsiform, and perciform fishes,

1397 many of which also represent the same fish families in Maastrichtian and Eocene deposits. The

1398 only higher-level taxa recovered from Maastrichtian deposits but unknown from Paleocene or

1399 younger deposits are the Elopiformes and Wilsonichthyidae, suggesting that they may have been

1400 extirpated from the North American Western Interior or gone extinct, respectively, in the interim,

1401 possibly during the end-Cretaceous mass extinction event. Conversely, several genera found in

1402 the Green River Formation, including ‘Priscacara’, Notogoneus, and potentially Mioplosus,

1403 were recovered in deposits predating the K/Pg boundary, indicating that at least some of these

1404 taxa originated prior to—and survived—the mass extinction event. However, several of the

1405 morphological characters used to describe Green River fishes rely on data that cannot be

1406 preserved in any but pristine, articulated specimens (including meristics, relative placement of

1407 fin insertion points, etc.). Consequently, this somewhat reduces the usefulness of any comparison

1408 with the majority of fluvially deposited material, which are most common in Cretaceous and

1409 Cenozoic formations of North America.

1410 The diversity of Paleogene teleost assemblages can further be estimated through

1411 comparisons with a taphonomically similar vertebrate microfossil assemblage from the early

1412 Eocene Bitter Creek locality of the Wasatch Formation, Wyoming (Fig. 1), which, like the

1413 Cretaceous localities, contains a mixture of isolated elements of terrestrial and aquatic animals

1414 that accumulated as a result of fluvial activity. However, it should be noted that the Wasatch

1415 assemblage described by Divay and Murray (2016a) was deposited in the uniformly shallow,

1416 slow-moving floodplain waters of small ponds connected to an active river system. This likely

1417 limited its accessibility to certain taxa, especially larger fishes, as indicated by the assemblage

1418 being exclusively composed of very smallDraft elements representing smaller, and often juvenile,

1419 fishes (Divay and Murray 2016a). In turn, this probably indicates that the diversity represented in

1420 that assemblage is lower than the diversity of the area at the time of deposition (Divay and

1421 Murray, 2016a). Nevertheless, with only between five and nine kinds of teleosts present in the

1422 Bitter Creek locality (Divay and Murray 2016a), the diversity of the Bitter Creek teleost

1423 assemblage is low compared with assemblages from the upper Maastrichtian formations we

1424 document here. Despite this, they are similar in that three of the taxa present in the Bitter Creek

1425 locality, aff. Amblyopsidae percopsiforms, Notogoneus, and ‘Priscacara’, are likely closely

1426 related to taxa present in the late Maastrichtian. One additional Bitter Creek taxon, Diplomystus,

1427 is also present in the Upper Cretaceous Belly River Group (Brinkman 2019) but not in the

1428 Maastrichtian localities included in this study.

1429 The apparent lower diversity of Paleogene teleosts suggests that they may have suffered

1430 higher extinction rates across the K/Pg boundary than what has previously been suggested (e.g.,

1431 33% extinction of teleost genera and species from the northern Western Interior, Archibald and

1432 Bryant 1990:table 2), although those effects do not appear to have influenced diversities at

1433 relatively higher taxonomic levels. Alternatively, the difference in known diversities of teleosts

1434 of the late Maastrichtian and early Eocene may reflect our relatively poorer understanding of the

1435 North American Paleocene ichthyofauna. To resolve between these two possibilities, additional

1436 samples from the early Paleocene that are preserved under taphonomic conditions similar to

1437 those studied here are necessary to more fully document the magnitude of teleost extinctions

1438 during the end-Cretaceous mass extinction in North America.

1439

Acknowledgements 1440 Draft 1441 This study would not have been possible without the efforts of an army of students,

1442 volunteers, and professionals who processed samples from numerous vertebrate microfossil

1443 localities. Although the focus of the work was often mammals, all vertebrate fossils were

1444 removed and made available for subsequent faunal studies. Among these, we would like to

1445 particularly thank John Maccagno for many hours he spent sorting samples from the TMP,

1446 including the samples from the Scollard Formation that are included in this study. Thanks to Pat

1447 Holroyd for access to specimens in the collections of the UCMP. Bill Clemens (UCMP)

1448 provided information on the localities, including an on-site summary of history of work on the

1449 Bug Creek Anthills locality. For access to specimens in the collections of the UWBM, we would

1450 like to thank Ron Eng, and Meredith Rivin. The Bureau of Land Management, Charles M.

1451 Russell Wildlife Refuge, Montana Department of Natural Resources and Conservation, and

1452 Montana Fish, Wildlife, and Parks provided logistical support and special use permits for the

1453 collection of vertebrate fossils from the Hell Creek Formation. For access to and donation of

1454 specimens from the Hauso 1 locality we thank the Tharp family. We thank the Myhrvold and

1455 Havranek Charitable Family Fund for funding the Hell Creek Project that supported the

1456 collection of many of the UWBM and MOR specimens studied herein. For access to collections

1457 in the UALVP we would like to thank Clive Coy and Alison Murray. DB would also like to

1458 thank Richard Fox for his introduction to vertebrate microfossil localities and long-term

1459 mentoring in the science and philosophy of paleontology. For access to collections in the ROM

1460 we would like to thank Kevin Seymour and David Evans. For access to recent comparative

1461 material, we would additionally like to thank Stephen Cumbaa and Margaret Currie (Canadian

1462 Museum of Nature), Douglas Nelson (University of Michigan Museum of Zoology), Gloria

1463 Arratia and Andrew Bentley (Kansas University). For access to the KUA2 locality we would like

1464 to thank the Griffith family. We also acknowledgeDraft the collections staff at the TMP for their

1465 support in curating the large and diverse samples that have resulted from the screenwashing

1466 activities undertaken during the past thirty-five years at the museum. Finally, we thank Mark

1467 Wilson, an anonymous reviewer, and CJES editor Kathlyn Stewart for helping to improve our

1468 manuscript with their constructive comments and suggestions.

1469

1470 References

1471 Archibald, J.D., and Bryant, L.J. 1990. Differential Cretaceous/Tertiary extinctions of nonmarine

1472 vertebrates; Evidence from northeastern Montana, In Global Catastrophes in Earth

1473 History: An Interdisciplinary Conference on Impacts, Volcanism, and Mass Mortality.

1474 Edited by V.L. Sharpton and P.D. Ward. Geological Society of America Special Paper

1475 247, pp. 549–562.

1476 Arratia G. 1997. Basal teleosts and teleostean phylogeny. Palaeo Ichthyologica, 7: 1–168.

1477 Arratia, G. 1999. The monophyly of Teleostei and stem-group teleosts. Consensus and

1478 disagreements. In Mesozoic fishes 2 – systematics and fossil record. Edited by G. Arratia

1479 and H.-P. Schultze. Verlag Dr. Friedrich Pfeil, München, Germany, pp. 265–334.

1480 Badgley, C. 1986. Counting individualsDraft in mammalian fossil assemblages from fluvial

1481 environments. Palaios, 1: 328–338. DOI: 10.2307/3514695

1482 Béland, P., Feldman, P., Foster, J., Jarzen, D., Norris, G., Pirozynski, K., Reid, G., Roy, J.-R.,

1483 Russell, D., and Tucker, W. 1977. Cretaceous-Tertiary extinctions and possible

1484 terrestrial and extraterrestrial causes. Syllogues 12: 1–162.

1485 https://www.biodiversitylibrary.org/item/111511#page/1/mode/1up

1486 Berg, L.S. 1936. The suborder Esocoidei (Pisces). Izvestia Biologicheskogo Nauchno-

1487 Issledovatel’skogo institute pri Permskom, 10: 385–391. [in Russian].

1488 Berg, L.S. 1940. Classification of fishes, both Recent and fossil. Travaux de l’Institut

1489 Zoologique de l’Académie des Sciences de l’URSS, 5: 1–45.

1490 Bleeker, P. 1859. Enumeratio speciorum piscium hucusque in Archipelago Indico observatarum,

1491 Acta Societatis Scientiarum Indo-Neêrlandae, 6: 1–276.

1492 Brinkman, D.B. 1990. Paleoecology of the Judith River Formation (Campanian) of Dinosaur

1493 Provincial Park, Alberta, Canada: Evidence from vertebrate microfossil localities.

1494 Palaeogeography, Palaeoclimatology, Palaeoecology, 78: 37–54. doi.org/10.1016/0031-

1495 0182(90)90203-J

1496 Brinkman, D.B. 2008. The structure of Late Cretaceous (Late Campanian) non-marine aquatic

1497 communities: A guild analysis of two vertebrate microfossil localities in Dinosaur

1498 Provincial Park, Alberta, Canada. In Vertebrate microfossil assemblages, their role in

1499 Paleoecology and Paleobiogeography. Edited by J.T. Sankey and S. Baszio. Indiana

1500 University Press, Bloomington, Indiana, pp. 33–60.

1501 Brinkman, D.B. 2019. Teleost abdominal centra from the Belly River Group of Alberta, Canada.

1502 Paludicola, 12: 109–152. Draft

1503 Brinkman, D.B., and Neuman, A.G. 2002. Teleost centra from uppermost Judith River Group

1504 (Dinosaur Park Formation, Campanian) of Alberta, Canada. Journal of Paleontology, 76:

1505 138–155. doi.org/10.1017/S002233600001742X

1506 Brinkman, D.B., Newbrey, M.G., Neuman, A.G., and Eaton, J.G. 2013. Freshwater Osteichthyes

1507 from the Cenomanian to late Campanian of Grand Staircase-Escalante National

1508 Monument, Utah. In At the Top of the Grand Staircase: The Late Cretaceous of Southern

1509 Utah. Edited by A.L. Titus and M.A. Lowen. Indiana University Press, Bloomington,

1510 Indiana, pp. 195–236.

1511 Brinkman, D.B., Newbrey, M.G., and Neuman, A.G. 2014. Diversity and paleoecology of

1512 actinopterygian fish from vertebrate microfossil localities of the Maastrichtian Hell Creek

1513 Formation of Montana. In Through the End of the Cretaceous in the Type Locality of the

1514 Hell Creek Formation in Montana and Adjacent Areas. Edited by G.P. Wilson, W.A.

1515 Clemens, J.R. Horner, and J.H. Hartman. Geological Society of America Special Paper,

1516 503: 247–270. doi.org/10.1130/2014.2503(09)

1517 Brinkman, D.B., Neuman, A.G., and Divay, J.D. 2017. Non-marine fish of the late Santonian

1518 Milk River Formation of Alberta, Canada – evidence from vertebrate microfossil

1519 localities. Vertebrate Anatomy Morphology Palaeontology, 3: 7–46. DOI:

1520 10.18435/B5PP41

1521 Bruner, J. C. 2011. Chapter 2: a phylogenetic analysis of Percidae using osteology. In Biology,

1522 Management, and Culture of Walleye and Sauger. Edited by B. A. Barton. American

1523 Fisheries Association, Bethesda, Maryland, pp. 5–84. 1524 Bryant, L.J. 1989. Non-dinosaurian lowerDraft vertebrates across the Cretaceous-Tertiary boundary in 1525 northeastern Montana. University of California Publications Geological Sciences, 134: 1–

1526 107.

1527 Cavender, T. M. 1986. Review of the fossil history of North American freshwater fishes. In The

1528 Zoogeography of North American Freshwater Fishes. Edited by C. H. Hocutt and E. O.

1529 Wiley. John Wiley & Sons, New York, pp. 699–724.

1530 Cavin, L. 2002. Effects of the Cretaceous-Tertiary Boundary Event on Bony Fishes. In

1531 Geological and Biological Effects of Impact Events. Edited by E. Buffetaut and C.

1532 Koeberl. Springer Science & Business Media, Berlin, German. pp. 141–158.

1533 DOI:10.1007/978-3-642-59388-8_6

1534 Cifelli, R.L., Eberle, J.J., Lofgren, D.L., Lillegraven, J.A., and Clemens, W.A. 2004. Mammalian

1535 biochronology of the latest Cretaceous. In Late Cretaceous and Cenozoic mammals of

1536 North America: Biostratigraphy and Geochronology. Edited by M.O. Woodburne.

1537 Columbia University Press, New York, pp. 21–42.

1538 Cope, E.D. 1877. A contribution to the knowledge of the ichthyological fauna of the Green River

1539 shales: Bulletin of the United States Geological Survey of the Territories, 3: 807–819.

1540 Cope, E.D. 1885. Eocene paddle-ﬁsh and Gonorhynchidae [sic]. American Naturalist, 19: 1090–

1541 1091.

1542 Cuvier, G., and Valenciennes, A. 1846. Histoire Naturelle Des Poissons, Volume 19: Société

1543 Géologique de France, Strasbourg [1969 facsimile reprint; A. Asher and Company,

1544 Amsterdam].

1545 Dartevelle, E. and Casier, E. 1943. Les poissons fossiles du Bas-Congo et des régions voisines:

1546 (Première Partie.) Annales du DraftMusée du Congo Belge, A: Minéralogie, Géologie,

1547 Paléontologie 3, 2: 1–200.

1548 DeMar, D.G., Jr. 2016. Late Cretaceous and Paleocene Lissamphibia and Squamata of Montana

1549 and the end-Cretaceous mass extinction, PhD dissertation, University of Washington,

1550 Seattle, 334 pp.

1551 DeMar, D.G., Jr., Wilson, G.P., Brinkman, D.B., Holroyd, P.A., Smith, S.S., and Mercier, G.K.

1552 2016. Vertebrate faunal dynamics during the end-Cretaceous mass extinction: a

1553 synthesis from the fossil record of northeastern Montana, USA. Journal of Vertebrate

1554 Paleontology, Program and Abstracts, p. 124.

1555 Divay, J. D., and A. M. Murray. 2013. A mid-Miocene ichthyofauna from the Wood Mountain

1556 Formation, Saskatchewan, Canada. Journal of Vertebrate Paleontology, 33: 1269–1291.

1557 DOI: 10.1080/02724634.2013.773334.

1558 Divay, J. D., and A. M. Murray. 2015. The late Eocene–early Oligocene ichthyofauna from the

1559 Eastend area of the Cypress Hills Formation, Saskatchewan, Canada. Journal of

1560 Vertebrate Paleontology, 35: 1–25. DOI: 10.1080/02724634.2014.956877.

1561 Divay, J.D., and Murray, A.M. 2016a. An early Eocene fish fauna from the Bitter Creek area of

1562 the Wasatch Formation of southwestern Wyoming, U.S.A., Journal of Vertebrate

1563 Paleontology, 36: 5, DOI: 10.1080/02724634.2016.1196211.

1564 Divay, J. D., and A. M. Murray. 2016b. The fishes of the Farson Cutoff Fishbed, Bridger

1565 Formation (Eocene), greater Green River Basin, Wyoming, U.S.A. Journal of Vertebrate

1566 Paleontology e1212867:1–18. DOI: 10.1080/02724634.2016.1212867.

1567 Divay, J.D., Brinkman, D.B., and Neuman, A.G. 2019. Late Cretaceous Notogoneus from

1568 microvertebrate assemblages of Draftthe Dinosaur Park Formation, Campanian of southern

1569 Alberta, Canada, and insight into the ecology and evolution of early gonorynchids,

1570 Journal of Vertebrate Paleontology, e1699801:1–19. DOI:

1571 10.1080/02724634.2019.1699801.

1572 Eberth, D.A. 1990. Stratigraphy and sedimentology of vertebrate microfossil localities in the

1573 uppermost Judith River Formation (Campanian) of Dinosaur Provincial Park, south-

1574 central Alberta, Canada. Palaeogeography Palaeoclimatology Palaeoecology, 78: 1–36.

1575 doi.org/10.1016/0031-0182(90)90202-I.

1576 Eberth, D.A. and Brinkman, D.B. 1997. Paleoecology of an estuarine, incised-valley fill in the

1577 Dinosaur Park Formation (Judith River Group, Upper Cretaceous) of southern Alberta,

1578 Canada. Palaios, 12: 43–58. DOI: 10.2307/3515293.

1579 Estes, R. 1964. Fossil vertebrates from the Late Cretaceous Lance Formation, Eastern Wyoming.

1580 University of California Publications in Geological Sciences, 49: 1–187.

1581 Estes, R. 1969a. Studies on fossil phyllodont fishes: Interrelationships and evolution in the

1582 Phyllodontidae (Albuloidei). Copeia,, 1969: 317–331. DOI: 10.2307/1442082.

1583 Estes, R. 1969b. Two new Late Cretaceous fishes from Montana and Wyoming. Breviora, 335:

1584 1–15.

1585 Estes, R., and Hiatt, R. 1978. Studies on fossil phyllodont fishes: a new species of Phyllodus

1586 (Elopiformes, Albuloidea) from the Late Cretaceous of Montana. PaleoBios, 28: 1–10.

1587 Estes, R., Berberian, P., and Meszoely, C.A.M. 1969. Lower vertebrates from the Late

1588 Cretaceous Hell Creek Formation, McCone County, Montana. Breviora, 337: 1–33.

1589 Fink, S.V., and Fink, W.L. 1996. Interrelationships of Ostariophysan fishes (Teleostei). In

1590 Interrelationships of Fishes. Edited by M.L.J. Stiassny, L.R. Parenti, and G.D. Johnson.

1591 Academic Press, San Diego, California,Draft pp. 209–250.

1592 Forey, P.L., Littlewood, D.T.J, Ritchie, P., and Meyer, A. 1996. Interrelationships of

1593 Elopomorph Fishes. ). In Interrelationships of Fishes. Edited by M.L.J. Stiassny, L.R.

1594 Parenti, and G.D. Johnson. Academic Press, San Diego, California, pp. 175–191

1595 Forsskål, P. 1775. Descriptiones animalium avium, amphibiorum, piscium, insectorum,

1596 vermium; quae in itinere orientali observavit; Post mortem auctoris edidit Carsten

1597 Niebuhr. Hauniae. Descriptiones animalium quae in itinere ad Maris Australis terras per

1598 annos, 1–20 + i–xxxiv + 1–164, map.

1599 Garstang, W. 1931. The phyletic classification of Teleostei. Proceedings of the Leeds

1600 Philosophical and Literary Society science section, 2: 240–260.

1601 Grande, L. 1984. Paleontology of the Green River Formation, with a review of the fish fauna,

1602 Second Edition. Geological Survey of Wyoming, Bulletin, 63: 1–333.

1603 Grande, L. 1988. A well preserved paracanthopterygian fish (Teleostei) from freshwater lower

1604 Paleocene deposits of Montana. Journal of Vertebrate Paleontology, 8: 117–130.

1605 doi.org/10.1080/02724634.1988.10011692.

1606 Grande, L. 2001. An updated review of the fish faunas from the Green River Formation, the

1607 world’s most productive freshwater lagerstätten. In Topics in Geobiology, Volume 18:

1608 Eocene Biodiversity: Unusual Occurrences and Rarely Sampled Habitats. Edited by G.

1609 F. Gunnell. Kluwer Academic/Plenum Publishers, New York, NY. pp. 1–38.

1610 Grande, L. 2013. The Lost World of Fossil Lake: Snapshots from Deep Time. University of

1611 Chicago Press, Chicago, Illinois, 425 pp.

1612 Grande, T., and Arratia, G. 2010. Morphological analysis of the gonorynchiform postcranial

1613 skeleton. In Gonorynchiformes andDraft Ostariophysan Relationships—A Comprehensive

1614 Review. Edited by T. Grande, F. J. Poyato-Ariza, and R. Diogo. Science Publishers,

1615 Enﬁeld, New Hampshire, pp. 39–71.

1616 Grande L., and Cavender, T.M. 1991. Description and phylogenetic reassessment of the

1617 monotypic †Ostariostomidae (Teleostei). Journal of Vertebrate Paleontology, 11: 405–

1618 416. doi.org/10.1080/02724634.1991.10011412.

1619 Grande, L., and Grande, T. 1999. A new species of †Notogoneus (Teleostei: Gonorynchidae)

1620 from the Upper Cretaceous Two Medicine Formation of Montana, and the poor

1621 Cretaceous record of freshwater fishes from North America, Journal of Vertebrate

1622 Paleontology, 19: 612–622. doi.org/10.1080/02724634.1999.10011175.

1623 Greenwood, P.H., Rosen, D.E., Weitzman, S.H., and Myers, G.S. 1966. Phyletic studies of

1624 teleostean fishes, with a provisional classification of living forms. Bulletin of the

1625 American Museum of Natural History, 131: 339–455. hdl.handle.net/2246/1678

1626 Haseman, J. D. 1912. The relationship of the genus Priscacara. American Museum of Natural

1627 History Bulletin 31:97–101.

1628 Hatcher, J.B. 1900. The Carnegie Museum paleontological expeditions of 1900. Science, 7: 718–

1629 720. DOI: 10.1126/science.12.306.718.

1630 Hesse, C. J. 1936. A new species of the genus Priscacara from the Eocene of Washington.

1631 Journal of Geology 44:745–750.

1632 Hilton, E.J. 2003. Comparative osteology and phylogenetic systematics of fossil and living bony-

1633 tongue fishes (Actinopterygii, Teleostei, Osteoglossomorpha). Zoological Journal of the

1634 Linnean Society, 137: 1–100. doi.org/10.1046/j.1096-3642.2003.00032.x.

1635 Holroyd, P.A., Wilson, G.P., and Hutchison, J.H. 2014. Temporal changes within the latest

1636 Cretaceous and early Paleogene Draftturtle faunas of northeastern Montanain. In Through the

1637 End of the Cretaceous in the Type Locality of the Hell Creek Formation in Montana and

1638 Adjacent Areas. Edited by G.P. Wilson, W.A. Clemens, J.R. Horner, and J.H. Hartman.

1639 Geological Society of America Special Paper, 503: 299–312.

1640 doi.org/10.1130/2014.2503(11).

1641 Horner, J.R., Goodwin, M.B. and Myhrvold, N. 2011. Dinosaur census reveals abundant

1642 Tyrannosaurus and rare ontogenetic stages in the Upper Cretaceous Hell Creek

1643 Formation (Maastrichtian), Montana, USA. PloS One 6(2): e16574.

1644 doi.org/10.1371/journal.pone.0016574.

1645 Johnson, G.D., and Patterson, C. 1996. Relationships of Lower Euteleostean Fishes. ). In

1646 Interrelationships of Fishes. Edited by M.L.J. Stiassny, L.R. Parenti, and G.D. Johnson.

1647 Academic Press, San Diego, California, pp. 251–332.

1648 Jordan, D.S. 1923. A classiﬁcation of ﬁshes, including families and genera as far as known.

1649 Stanford University Publications, Biological Sciences, 3: 77–243.

1650 doi.org/10.5962/bhl.title.161386

1651 Keating, B.H. and Helsing, C.E. 1983 The magnetostratigraphy of the Cretaceous-Tertiary

1652 boundary in the continental Lance Formation and five marine sequences. Eos,

1653 Transactions, American Geophysical Union, 64: 219.

1654 Larson, D.W., Brinkman, D.B., and Bell, P.R. 2010. Faunal assemblages from the upper

1655 Horseshoe Canyon Formation, an early Maastrichtian cool-climate assemblage from

1656 Alberta, with special reference to the Albertosaurus sarcophagus bonebed. Canadian

1657 Journal of Earth Sciences, 47: 1159–1181. doi:10.1139/E10-005.

1658 Lavoué, S. 2016. Was Gondwanan breakupDraft the cause of the intercontinental distribution of

1659 Osteoglossiformes? A time-calibrated phylogenetic test combining molecular,

1660 morphological, and paleontological evidence. Molecular phylogenetics and evolution, 99:

1661 34–43. doi: 10.1016/j.ympev.2016.03.008.

1662 Li G. -Q., and Wilson, M.V.H. 1996. The discovery of heterotidinae (Teleostei: Osteoglossidae)

1663 from the Paleocene Paskapoo formation of Alberta, Canada. Journal of Vertebrate

1664 Paleontology, 16: 198–209. doi.org/10.1080/02724634.1996.10011308.

1665 Lillegraven, J.A. 1969. Latest Cretaceous mammals of upper part of Edmonton Formation of

1666 Alberta, Canada, and review of marsupial-placental dichotomy in mammalian evolution.

1667 University of Kansas Paleontological Contributions, Vertebrata, 50: 1–222.

1668 hdl.handle.net/1808/3825.

1669 Marsh, O.C. 1889. Discovery of Cretaceous Mammalia, part 2. American Journal of Science (3),

1670 43: 249–262

1671 McKenna, M.C. 1962. Collecting small fossils by washing and screening. Curator, 5: 221–235.

1672 doi.org/10.1111/j.2151-6952.1962.tb01586.x.

1673 Mercier, G.K., DeMar, D.G. Jr., and Wilson, G.P. 2014. Frogs and toads (Lissamphibia, Anura)

1674 during the end-Cretaceous mass extinction: evidence from the fossil record of

1675 northeastern Montana. Society of Vertebrate Paleontology, 74th Annual Meeting, 5–8

1676 Nov., Estrel Berlin, Berlin, Germany, Program and Abstracts, p. 187.

1677 Müller, J. 1846. Über den Bau und die Grenzen der Ganoiden und über das natürlichen System

1678 der Fische. Abhandlungen Akademie der Wissenschaften, Berlin, 1844: 117–216.

1679 Murray, A.M. 1996. A new Paleocene genus and species of percopsid,† Massamorichthys

1680 wilsoni (Paracanthopterygii) from Joffre Bridge, Alberta, Canada. Journal of Vertebrate

1681 Paleontology, 16: 642–652. doi.org/10.1080/02724634.1996.10011354.Draft

1682 Murray, A.M, and Wilson, M.V.H. 1996. A new Palaeocene genus and species of percopsiform

1683 (Teleostei: Paracanthopterygii) from the Paskapoo Formation, Smoky Tower, Alberta.

1684 Canadian Journal of Earth Sciences, 33: 429–438. doi.org/10.1139/e96-032

1685 Murray, A.M., Newbrey, M.G., Neuman, A.G., and Brinkman, D.B. 2016. New articulated

1686 osteoglossomorph from Late Cretaceous freshwater deposits (Maastrichtian, Scollard

1687 Formation) of Alberta, Canada. Journal of Vertebrate Paleontology, 36:4, DOI:

1688 10.1080/02724634.2016.1120737.

1689 Murray, A.M., Zelenitsky, D.K., Brinkman, D.B., and Neuman, A.G. 2018. Two new Palaeocene

1690 osteoglossomorphs from Canada, with a reassessment of the relationships of the genus

1691 Joffrichthys, and analysis of diversity from articulated versus microfossil material.

1692 Zoological Journal of the Linnean Society, 183: 907–944.

1693 doi.org/10.1093/zoolinnean/zlx100.

1694 Murray, A.M., Brinkman, D.B., Newbrey, M.G., and Neuman, A.G. 2019. Earliest North

1695 American articulated freshwater acanthomorph fishes (Teleostei: Percopsiformes) from

1696 the Late Cretaceous of Alberta, Canada. Geological Magazine, 157: 1087–1096.

1697 doi:10.1017/S0016756819001328.

1698 Neuman, A.G., and Brinkman, D.B. 2005. Fishes of the fluvial beds. In Dinosaur Provincial

1699 Park, A Spectacular Ancient Ecosystem Revealed. Edited by P.J. Currie and E B.

1700 Kopplelhus. Indiana University Press, Bloomington, Indiana, pp. 167–185

1701 Newbrey, M.G. and Bozek, M.A. 2000. A new species of Joffrichthys (Teleostei:

1702 Osteoglossidae) from the Sentinel Butte Formation,(Paleocene) of North Dakota, USA.

1703 Journal of Vertebrate Paleontology, 20: 12–20. doi.org/10.1671/0272-

1704 4634(2000)020[0012:ANSOJT]2.0.CO;2.Draft

1705 Newbrey, M.G., Murray, A.M., Wilson, M.V.H., Brinkman, D B., and Neuman, A.G. 2009.

1706 Seventy-five-million-year-old tropical tetra-like fish from Canada tracks Cretaceous

1707 global warming. Proceedings of the Royal Society, B, 276: 3829–3833.

1708 doi.org/10.1098/rspb.2009.1047.

1709 Newbrey, M.G., Brinkman, D.B., Winkler, D.A., Freedman, E.A., Neuman, A.G., Fowler, D.W.,

1710 and Woodward, H.N. 2013. Teleost centrum and jaw elements from the Late Cretaceous

1711 Nemegt Formation (Campanian – Maastrichtian) of Mongolia and a re-identification of

1712 the fish centrum found with the theropod Raptorex kreigsteini. In Mesozoic Fishes 5 –

1713 Global Diversity and Evolution. Edited by G. Arratia, H.–P Schultze, and M.V.H.

1714 Wilson. Verlag Dr. Friedrich Pfeil, Munich, Germany, pp 291–303.

1715 Patterson, C. 1993. An overview of the early fossil record of acanthomorphs. Bulletin of Marine

1716 Science, 52: 29–59.

1717 Patterson, C., and Rosen, D.E. 1977. A review of the ichthyodectiform and other Mesozoic

1718 teleost fishes, and the theory and practice of classifying fossils. Bulletin of the American

1719 Museum of Natural History, 158: 81–172. hdl.handle.net/2246/1224.

1720 Peng, J.H, Russell, A.P., and Brinkman, D.B. 2001. Vertebrate Microsite assemblages (exclusive

1721 of mammals) from the Foremost and Oldman Formations of the Judith River Group

1722 (Campanian) of Southeastern Alberta: An Illustrated Guide. Provincial Museum of

1723 Alberta Natural History Occasional Paper, 25: 1–54.

1724 Rosen, D.E., and Greenwood, P.H. 1970. Origin of the Weberian apparatus and the relationships

1725 of the ostariophysan and gonorynchiform fishes. American Museum Novitates, 2428: 1–

1726 5. hdl.handle.net/2246/2638.

1727 Rosen, D.E. and Patterson, C., 1969. TheDraft structure and relationships of the paracanthopterygian

1728 fishes. Bulletin of the American Museum of Natural History, 141: 357–474.

1729 hdl.handle.net/2246/1996.

1730 Russell, D., and W. Tucker. 1971/ Supernovae and the Extinction of the Dinosaurs. Nature 229,

1731 553–554. https://doi.org/10.1038/229553a0

1732 Sagemehl, M. 1885. Beiträge zur vergleichenden Anotomie der Fische. III. Das Cranium der

1733 Characiniden nebst allgemeinen Bemerkungen über die mit einen Weber’schen Apparat

1734 versehenen Physostomenfamilien. Gegenbauers Morphologisches Jahrbuch, 10: 1–119.

1735 Sankey, J.T. and Baszio, S. 2008. Vertebrate Microfossil Assemblages, Their Role in

1736 Paleoecology and Paleobiogeography. Indiana University Press, Bloomington, Indiana.

1737 Schaeffer, B. 1949. A teleost from the Livingston Formation of Montana. American Museum

1738 Novitates, 1427: 1–16. hdl.handle.net/2246/2348.

1739 Sinha, S., Brinkman, D.B., and Murray, A.M. 2019. A morphological study of vertebral centra in

1740 extant species of pike, Esox (Teleostei: Esociformes). Vertebrate Anatomy Morphology

1741 Palaeontology, 7: 111–128. doi.org/10.18435/vamp29357.

1742 Smith, W.L. and Craig, M.T., 2007. Casting the percomorph net widely: the importance of broad

1743 taxonomic sampling in the search for the placement of serranid and percid fishes. Copeia,

1744 2007: 35–55. doi.org/10.1643/0045-8511(2007)7[35:CTPNWT]2.0.CO;2.

1745 Sprain, C.J., Renne, P. R., Clemens, W.A., and Wilson, G.P. 2018. Calibration of chron C29R:

1746 New high-precision geochronologic and paleomagnetic constraints from the Hell Creek

1747 region, Montana. The Geological Society of America Bulletin, 130: 1615–1644.

1748 doi.org/10.1130/B31890.1

1749 Stiassny, M.L.J. 1986. The limits and relationshipsDraft of the acanthomorph teleosts. Journal of

1750 Zoology, 1: 411–460. doi.org/10.1111/j.1096-3642.1986.tb00644.x.

1751 Taverne, L. 1979. Ostéologie, phylogénèse et systématique des Téléostéens fossiles et actuels du

1752 super-ordre des osteoglossomorphes. Troisième partie. Évolution des structures

1753 ostéologiques et conclusions générales relatives à la phylogénèse et à la systématique du

1754 super-order. Mémoires de la Classe des Sciences, Académie Royale de Belgique, 43: 1–

1755 168.

1756 Whitlock, J.A. 2010. Phylogenetic relationships of the Eocene percomorph fishes †Priscacara

1757 and †Mioplosus. Journal of Vertebrate Paleontology, 30: 1037–1048.

1758 doi.org/10.1080/02724634.2010.483534.

1759 Wilson, G.P. 2005. Mammalian faunal dynamics during the last 1.8 million years of the

1760 Cretaceous in Garfield County, Montana. Journal of Mammalian Evolution, 12: 53–76.

1761 doi:10.1007/s10914-005-6943-4.

1762 Wilson, G.P. 2014, Mammalian extinction, survival, and recovery dynamics across the

1763 Cretaceous-Paleogene boundary in northeastern Montana. In Through the End of the

1764 Cretaceous in the Type Locality of the Hell Creek Formation in Montana and Adjacent

1765 Areas. Edited by G.P. Wilson, W.A. Clemens, J.R. Horner, and J.H. Hartman (eds.),

1766 Geological Society of America Special Paper, 503: 365–392. doi:10.1130/2014.2503(15).

1767 Wilson, G.P., Dechesne, M., and Anderson, I.R. 2010. New latest Cretaceous mammals from

1768 northeastern Colorado with biochronologic and biogeographic implication. Journal of

1769 Vertebrate Paleontology, 30:4 99–520. doi:10.1080/02724631003620955.

1770 Wilson, G.P., DeMar, D.G. Jr., and Carter, G. 2014. Extinction and survival of salamander and

1771 salamander-like amphibians across the Cretaceous-Paleogene boundary in northeastern

1772 Montana, USA. In Through the EndDraft of the Cretaceous in the Type Locality of the Hell

1773 Creek Formation in Montana and Adjacent Areas. Edited by G.P. Wilson, W.A. Clemens,

1774 J.R. Horner, and J.H. Hartman (eds.), Geological Society of America Special Paper, 503:

1775 271–297. doi:10.1130/2014.2503(10).

1776 Wilson, M. V. H. 1977. Middle Eocene freshwater fishes from British Columbia. Royal Ontario

1777 Museum Life Sciences Contributions 113:1–62.

1778 Wilson, M.V.H., 1980. Oldest known Esox (Pisces: Esocidae), part of a new Paleocene teleost

1779 fauna from western Canada. Canadian Journal of Earth Sciences, 17: 307–312.

1780 doi.org/10.1139/e80-030

1781 Wilson, M.V.H. and Murray, A.M. 2008. Osteoglossomorpha: phylogeny, biogeography, and

1782 fossil record and the significance of key African and Chinese fossil taxa. Geological

1783 Society, London, Special Publications, 295: 185–219. doi.org/10.1144/SP295.12.

1784 Wilson, M.V.H. and Williams, R.R. 1991. New Paleocene genus and species of smelt (Teleostei:

1785 Osmeridae) from freshwater deposits of the Paskapoo Formation, Alberta, Canada, and

1786 comments on osmerid phylogeny. Journal of Vertebrate Paleontology, 11: 434–451.

1787 doi.org/10.1080/02724634.1991.10011414.

1788 Wilson, M.V.H., Brinkman, D.B., and Neuman, A.G. 1992. Cretaceous Esocoidea (Teleostei):

1789 early radiation of the pikes in North American fresh waters. Journal of Paleontology, 66:

1790 839–846. doi.org/10.1017/S0022336000020849

1791 Woodward, A. S. 1901. Catalogue of the Fossil Fishes in the British Museum (Natural History),

1792 Volume 4:554–556. British Museum (Natural History), London.

1793 Wynd, B.M., DeMar, D.G. Jr., and Wilson, G.P. 2020. Euselachian diversity through the

1794 uppermost Cretaceous Hell CreekDraft Formation of Garfield County, Montana, USA, with

1795 implications for the Cretaceous-Paleogene mass extinction in freshwater environments.

1796 Cretaceous Research, 113: 104483. doi.org/10.1016/j.cretres.2020.104483

1797

1798 Appendix 1:

1799 Below is a list of specimens of recent teleost fishes used for comparison with the fossil

1800 material. Institutional abbreviations: CMN, Canadian Museum of Nature; KU, Kansas

1801 University; ROM, Royal Ontario Museum; TMP, Royal Tyrrell Museum of Palaeontology;

1802 UAMZ, University of Alberta Museum of Zoology; UCMP, University of California Museum of

1803 Paleontology; UF, University of Florida; UMMZ, University of Michigan Museum of Zoology.

1804 Elopiformes, Elopidae, Elops saurus: ROM R7420; Megalops atlanticus: ROM R6903.

1805 Albuliformes, Albulidae, Albula vulpes: UF27125, Z2664.

1806 Anguilliformes, Anguillidae, Anguilla rostrata: ROM R1721.

1807 Hiodontiformes, Hiodontidae, Hiodon alosoides: UAMZ F8556; UCMP 131954.

1808 Osteoglossiformes, Gymnarchidae,Draft Gymnarchus niloticus, ROM R6615;

1809 Osteoglossidae, Arapaima gigas: UCMP 136660, UCMP 84694; Osteoglossum bicirrhosum:

1810 UCMP 82959, UCMP 136658, TMP 2007.030.0007; Scleropages formosa: ROM R6669, UCMP

1811 131863; Notoperidae, Notopterus notopterus: UCMP 136653; Notopterus milkereedi: UCMP

1812 136655.

1813 Clupeiformes, Clupeidae, Alosa chrysochloris: ROM R3351; Alosa pseudoharengus:

1814 ROM R1508; Brevoortia smithi: ROM R1572; Clupea harengus: ROM R5454; Dorosoma

1815 cepedianum: ROM R6277; Harengula jaguana: ROM R4972; Opisthonema oglinum: ROM

1816 R4860; Sardina pilchardus: ROM R5243; Sardinella aurita: ROM R5102; Engraulidae,

1817 Cetengraulis edentulus: ROM R5103; Engraulis mordax: ROM R3859; Lycengraulis

1818 grossidens: ROM R5119.

1819 Gonorynchiformes, Chanidae, Chanos chanos: TMP 2017.030.0001, UAMZ F8550;

1820 Gonorynchus forsteri: TMP 2015.030.0003.

1821 Cypriniformes, Cyprinidae, Campostoma anomalum: ROM R7890; Chrosomus eos:

1822 ROM R7897; Clinostomus elongatus: ROM R7754; Cyprinella spiloptera: ROM R6823;

1823 Cyprinus carpio: ROM R5003, TMP 2007.30.9, UAMZ F8557, UCMP 122580; Hybognathus

1824 hankinsoni: ROM R2569; Labeo dero: UCMP 128164; Luxilus cornutus, ROM R6425;

1825 Macrhybopsis storeriana, ROM R6385; Nocomis biguttatus: ROM R5358; Notemigonus

1826 crysoleucas: ROM R7664; Notropis atherinoides: ROM R2561; Pimephales notatus: ROM

1827 R7750; Ptychocheilus oregonensis: UCMP 136672; Semotilus atromaculatus: ROM R5885;

1828 Semotilus margarita: CMN Z-668. Catostomidae, Carpiodes carpio: KU 12732; Carpiodes

1829 cyprinus: CMN 77-183; Catostomus catostomus: UAMZ F8558, UAMZ F8582; Catostomus

1830 commersonii: ROM R2745; Catostomus occidentalis: UCMP 122584; Ictiobus cyprinellus: KU

1831 15337, ROM R1722; Moxostoma macrolepidotumDraft: UAMZ 6492, ROM R7377; Moxostoma

1832 valenciennesi: ROM R7659.

1833 Characiformes, Cynodontidae, Hydrolycus scomberoides: UMMZ Z04957.

1834 Serrasalmidae, Colossoma macropomum: ROM R7580; Metynnis hypsauchen: UCMP 136676.

1835 Siluriformes, Ariidae, Ariopsis felis: UCMP 122569, UMMZ 186995; Bagre marinus:

1836 ROM R1809; Clariidae, Clarias batrachus: ROM R8806; Ictaluridae, Ameiurus melas: TMP

1837 2010.4.3; Ameiurus natalis: ROM R7245; Ameiurus nebulosus: CMN 77-254; ROM R3212,

1838 ROM R3214; Ictalurus punctatus: UAMZ F8553; Noturus flavus: CMN 77-182; ROM R1982;

1839 UAMZ 7527; Pylodictis olivaris: UCMP 140211. Siluridae, Phalacronotus bleekeri: ROM

1840 R8751.

1841 Salmoniformes, Salmonidae, Coregonus clupeaformis: CMN 73-259b; Oncorhynchus

1842 tshawytscha: ROM R2292; Prosopium cylindraceum: ROM R2228; Salvelinus fontinalis:

1843 UAMZ F8472; Stenodus leucichthys: CMN Z4206, UAMZ F9105; Thymallus arcticus: ROM

1844 R1754.

1845 Esociformes, Umbridae, Dallia pectoralis: ROM R1797; Umbra limi: CMN 87.323,

1846 ROM R2552, ROM R7818; Esocidae, Esox americanus: ROM R1736, ROM R8966, ROM

1847 R8967; Esox lucius: CMNFI 1977-0217.1, UAMZ F9077, ROM R2197, UAMZ F8551, UAMZ

1848 F8552, UAMZ F9079, UCMP 136670; Esox masquinongy: CMNFI 1978-0202.1, ROM R2243;

1849 Esox niger: CMN 87-385; ROM R1607; Esox reichertii: ROM R 8294.

1850 Osmeriformes, Osmeridae, Osmerus mordax: CMN Z-4079.

1851 Aulopiformes, Alepisauridae, Alepisaurus ferox: ROM R2802; UCMP 131948.

1852 Percopsiformes, Percopsidae, Percopsis omiscomaycus: CMN A-374, ROM R6493.

1853 Gadiformes, Gadidae MelanogrammusDraft aeglefinus: ROM R3195; Lotidae, Lota lota:

1854 CMN 85-603, ROM R1850, ROM R6397, UCMP 131570; Phycidae, Urophycis chuss: ROM

1855 R1867.

1856 Beryciformes, Holocentridae, Holocentrus adscensionis: ROM R2198, ROM R5211.

1857 Batrachoidiformes, Batracoididae, Opsanus tau: ROM R3117.

1858 Cyprinodontiformes, Fundulidae, Fundulus heteroclitus: ROM R3852.

1859 Perciformes, Centrarchidae, Lepomis gibbosus: CMN 73-236C; Lepomis macrochirus:

1860 ROM R6210; Micropterus dolomieui: ROM R6125, CMN 73-258; Pomoxis nigromaculatus:

1861 CMN 76-075; Morone americana: ROM R6327; Morone chrysops: ROM R3385, ROM R6377;

1862 Morone saxatilis: UAMZ F8554; Perca flavescens: UAMZ 4821, UMMZ 171120; UMMZ

1863 175905 (8 of 9).

1864

Table 1. Distribution of teleost taxa in the Hell Creek, Lance, and Scollard formations represented by isolated teeth or tooth-bearing elements.

Hell Creek Fm. Lance Scollard Taxon lower middle upper Fm. Fm. Phyllodus paulkatoi X Wilsonichthys aridinsulensis X X Wilsonichthys sp. X Coriops amnicolus X X Coriops sp. (large morph) X Aff. Lopadichthys X Ostariostoma X X Estesesox X X X X Percopsiformes sp. indet. X X X X Priscacara' sp. X Platacodon nanus X X X X X

Draft

Table 2. Summary counts of teleost centra from 10 vertebrate microfossil localities in the Hell Creek, Lance, and Scollard formations.

Hell Creek Fm. Lance lower middle upper ∑HC/taxon Fm.

Taxon/morphotype V99220 V99227 V99369 C1153 C1529 V77130 V73087 HC-656 comb. V5711 Elopiformes 2

Wilsonichthys aridinsulensis 7 6 22 39 15 5 114 208 33

?Wilsonichthys 28 5 35 9 3 7 1 88

Hiodontidae indet. (small morph) 3 9 6 1 2 19 40 4

Hiodontidae indet. (large morph) 1 1 2 4

Coriops or Lopadichthys (small) 36 93 21 47 5 4 10 2 218 36

Coriops or Lopadichthys (large) 28 28 8 1 6 12 2 85

Gonorhynchiformes indet. type H 2 2 8

Notogoneus 2 1 3 1 7

Otophysi indet. type U-3/BvD 1 2 7 4 17 31 14

Estesesox sp. 26 30 Draft36 74 13 1 30 3 213 6

Acanthomorpha type HC-1 5 3 1 68 70 14 247 2 410 19

Acanthomorpha type HC-2 12 26 44 17 11 6 111 227 6

Acanthomorpha type HC-3 2 2 7

Acanthomorpha type HC-4 1 5 2 2 1 11 22 6

Acanthomorpha type HC-5 3 12 15

Acanthomorpha type HC-6 2 1 3 1

Teleost indet. type U-4 2 2 12 7 7 104 2 136 10

Teleost indet. type RvB 2 2 4 1

locality subtotals: 148 206 188 283 126 51 700 13 153

formation and grand totals 1715 153

Notes: Hell Creek Formation samples are updated from Brinkman et al. (2014:table 4). Centrum counts are calculated for each taxon/morphotype per locality and formation, with the grand total of all specimens listed in the lower right-hand corner. Abbreviations: ∑HC/taxon = total count per taxon from the Hell Creek Formation; ∑total/taxon = total counts per taxon across all formations; comb. = combination of specimens from all localities across the Hell Creek or all formations. The alternating white and grey rows represent the higher-level taxonomic groupings and sample sizes used in calculating the relative abundance patterns shown in Figure 20.

Scollard Fm. ∑total/taxon KUA2 comb. 2 12 253

1 45

4 4 258

5 50

219 Draft

11 440

2 235

8 154

43 1911

Draft

Figure 1. Map of the Western Interior of North America showing the approximate locations of localities discussed in the text. 1: Paskapoo Formation, Joffrey Bridge locality, Alberta, Canada; 2, Paskapoo Formation, Calgary locality, Alberta, Canada; 3, Scollard Formation, KUA-2 locality, Alberta, Canada; 4: Hell Creek Formation, localities in Garfield and McCone Counties, Montana, USA; 5: Lance Formation, Bushy Tailed Blowout locality, Wyoming, USA; 6: Wasatch Formation, Bitter Creek locality, Wyoming, USA. Maastrichtian localities (3–5) are denoted by solid black circles (also includes the temporally mixed Bug Creek Anthills locality); Paleocene localities (1–2) are denoted by the open circles; the Eocene locality (6) is denoted by a solid black square. Map created using Photoshop 6, base map data: Google 2020.

165x254mm (72 x 72 DPI)

Draft

Figure 2. Examples of terms used to refer to anatomical features of teleost centra. A–C) centra of Estesesox in dorsal, lateral, and ventral views, anterior towards the left, specimen UALVP 58844; D) centrum of acanthomorph type HC-4 in dorsal view, specimen UCMP 191553/V99227, from the lower Hell Creek Formation; E–F) centrum of Wilsonichthys aridinsulensis shown in dorsal and ventral views, specimen TMP 2009.13.73, from the Scollard Formation. Abbreviations: neur arch art pit, neural arch articular pit; parapoph art pit, parapophyseal articular pit; mid-vent ridge, mid ventral ridge; mid-dors ridge, mid-dorsal ridge; mid-dor pit, mid-dorsal pit; mid-vent pit, mid-ventral pit. Scale bar equals 1 mm.

Figure 3. Elopomorph elements from the Late Cretaceous and early Paleocene. A) Elopiformes gen. indet. centrum shown in anterior, left lateral, posterior, dorsal and ventral views. UALVP 58837, from the Lance Formation. B–C) Phyllodus teeth from the early Paleocene Tullock Member of the Fort Union Formation showing variation in surface texture, both included in UCMP 191568/V73080. Draft

Draft

Figure 4. Wisonichthys elements. A) dentary of Wilsonichthys aridinsulensis, UCMP 198883/V99369, from the lower Hell Creek Formation. B) dentary of Wilsonichthys sp., UCMP 230683/V99220, from the lower Hell Creek Formation. C–E) centra of Wilsonichthys aridinsulensis, (also referred to as centrum type B-vE) shown in anterior left lateral, posterior, dorsal and ventral views; C, UCMP 191697(in part)/V99369, from the lower Hell Creek Formation; D, TMP 2009.13.73, from the Scollard Formation; E, UALVP 56054, from the Lance Formation. F–G) centra of Wilsonichthys sp. (also referred to as centrum type B-vA) shown in anterior left lateral, posterior, dorsal and ventral views; F, UCMP 191596/V99369, from the lower Hell Creek Formation; G, UCMP 230619/V73087, from the upper Hell Creek Formation. Figure A–B from Brinkman et al. (2013, fig. 12). Scale bar equals 2 mm.

Draft

Figure 5. Hiodontidae centra, shown in anterior, left lateral, posterior, dorsal and ventral views. A–C) centra of small-bodied hiodontid; A, first abdominal centrum, UCMP 191590/V99369, from the lower Hell Creek Formation; B, posterior abdominal centra, TMP 2015.37.23, from the Scollard Formation; C, posterior abdominal centra, uncatalogued UALVP specimen from the Lance Formation. D–F) centra of large-bodied hiodontid; D, first abdominal centrum, UCMP 191867/V77130, from the upper Hell Creek Formation; E, anterior abdominal centrum, UCMP 191595/V99369, from the lower Hell Creek Formation; F, mid abdominal centrum, UCMP 230616/V73087, from the upper Hell Creek Formation. Figures D–F from Brinkman et al., 2014, fig. 6. Scale bar equals 2 mm.

Draft

Figure 6. Osteoglossomorph tooth-bearing elements. A) basibranchial tooth-plates of Coriops amnicolus in dorsal and ventral views, UALVP 58853, from the Lance Formation; B) Right dentary of Aff. Lopadichthys in lateral, medial and occlusal views, UALVP 56055, from the Lance Formation; C) dentary referred to Ostariostoma, in lateral, medial and occlusal views, UALVP 56053, from the Lance Formation. Abbreviation: sens can pore, sensory canal pores. Scale bar equals 2 mm. ¬

Draft

Figure 7. Centra from Coriops or Lopadichthys, A) anterior abdominal centrum, UCMP 230745)/V77130, from the upper Hell Creek Formation; B) mid- abdominal centrum, TMP 2015.37.25, from the Scollard Formation; C) mid-abdominal centrum of large size, UCMP 230613/V73087, from the upper Hell Creek Formation; D) mid-abdominal centrum, UALVP 58846, from the Lance Formation; E) posterior abdominal centrum, UCMP 230612/V73087, from the upper Hell Creek Formation. Scale bar equals 2 mm.

Draft

Figure 8. Gonorynchiform centra, in anterior, left lateral, posterior, dorsal, and ventral views. A-C) Centra of teleost indet. type H; A, first abdominal centrum, UCMP 191589/V99369, from the lower Hell Creek Formation; B, mid-abdominal centrum, UALVP 58842, from the Lance Formation; C, posterior abdominal centrum, UALVP 58842, from the Lance Formation. D) Notogoneus abdominal centrum, UWBM 106470/C1111, from the lower Hell Creek Formation. Abbreviations: dor ridge, dorsal ridge; lat ridge, lateral ridge. Fig. 8A from Brinkman et al. 2013:fig. 10C. Scale bar equals 2 mm.

Draft

Figure 9. Centra of Ostariophysi indet. type U3/BvD, in anterior, left lateral, posterior, dorsal, and ventral views. A–B) anterior Weberian centra (centrum type U3); A, UALVP 58839, from the Lance Formation; B, UCMP 230678/V99220, from the lower Hell Creek Formation. C) third Weberian centrum (centrum type BvC), TMP 2020.60.10, from the Scollard Formation,. D) centrum tentatively identified as the fourth Weberian centrum, UALVP 58840, from the Lance Formation. E) abdominal centrum (centrum type BvD), UALVP 58838, from the Lance Formation. Scale bar equals 2 mm.

Draft

Figure 10. Esocid elements from the Late Maastrichtian. A–F) dentaries of Estesesox shown to scale; A–B, dentary of large size with single tooth row anteriorly, from the Scollard Formation, in A, occlusal and B, medial views, TMP 2009.13.275; C–D, dentary of intermediate size with double tooth row anteriorly from the lower Hell Creek Formation, in C, occlusal and D, medial views, UCMP 198885/V99369; E–F, dentary of small size with multiple tooth rows, from the Scollard Formation, in E, occlusal, and F, medial views, TMP 2009.13.302. G) palatine with two rows of teeth, in occlusal and dorsal views, UALVP 58854, from the Lance Formation. H–J) esocid centra in anterior, right lateral, posterior, dorsal and ventral views; H, centrum type NvC, interpreted as an anterior abdominal centrum UALVP 58844, from the Lance Formation; I, centrum type NvE, interpreted as a mid-abdominal centrum, UCMP 191591/V99369, from the lower Hell Creek Formation; J, centrum type NvD, interpreted as posterior abdominal centrum, UCMP 191691/V99369, from the lower Hell Creek Formation. A–B reversed for comparison. C–D from Brinkman et al. (2014:fig. 8B). Scale bar equals 2 mm.

Figure 11. Acanthomorph tooth-bearing elements. A–B) Percopsiformes dentaries in ventral lateral, occlusal and medial views; A, UCMP 198884/V99369, from the lower Hell Creek Formation; B, UALVP 59912, from the Lance Formation. C-D) ‘Priscacara’ dentaries in occlusal, lateral and medial views. C, UCMP 198873/V73087, from the upper Hell Creek Formation; D, TMP 2009.13.69, from Scollard Formation; E) Platacodon tooth plate, in (upper row) medial and lateral views, (middle row) anterior and posterior views, and (lower row) ventral and dorsal views, UALVP 58851, from the Lance Formation. Fig. 11C from Brinkman et al. (2014:fig. 11D) reversedDraft for comparison. Scale bar equals 2 mm.

Draft

Figure 12. Centra of Acanthomorph indet. type HC-1, in anterior, left lateral, posterior, dorsal, and ventral views. A–B) first abdominal centrum, A, UALVP 58830, from the Lance Formation; B, UCMP 230601/V73087, from the upper Hell Creek Formation. C–E) abdominal centra, showing variation along the column; C, anterior abdominal centrum, UCMP 230591/V73087, from the upper Hell Creek Formation; D, mid- abdominal centrum, TMP 2009.13.76, from the Scollard Formation; E, posterior abdominal centrum, UCMP 230599/V73087, from the upper Hell Creek Formation. Scale bar equals 2 mm.

Draft

Figure 13. Centra of Acanthomorph indet. centrum type HC-2, in anterior, left lateral, posterior, dorsal, and ventral views. A–B) first abdominal centrum; A, UCMP 297015/V99369, from the lower Hell Creek Formation; B, UALVP 58832, from the Lance Formation. C-D) abdominal centra; C, TMP 2015.37.26, from the Scollard Formation; D, UCMP 230593/V73087, from the upper Hell Creek Formation. Scale bar equals 2 mm.

Figure 14. First abdominal centra of Acanthomorph indet. centrum type HC-3, in anterior, left lateral, posterior, dorsal, and ventral views. A) UALVP 58833, from the Lance Formation; B) UCMP 297016/V99369, from the lower Hell Creek Formation. Scale bar equals 2 mm. Draft

Draft

Figure 15. Centra of Acanthomorph indet. centrum type HC-4, in anterior, left lateral, posterior, dorsal, and ventral views. A) first abdominal centrum, UALVP 58836, from the Lance Formation; B-D) abdominal centra showing variation along the column; B UALVP 58834, from the Lance Formation; C, UALVP 58834, from the Lance Formation; D, UCMP 191553/V99227, from the lower Hell Creek Formation. Scale bar equals 2 mm.

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Figure 16. Centra of Acanthomorph indet. type HC-5, in anterior, left lateral, posterior, dorsal, and ventral views. A–B) first abdominal centrum; A, ROM 59165, from the Bug Creek Anthills locality; B, TMP 2009.37.72, first abdominal, from the Scollard Formation; C-E) abdominal centra, arranged from more anterior to more posterior; C, ROM 59157, from the Bug Creek Anthills locality; D, ROM 59158, from the Bug Creek Anthills locality; and E, ROM 59159, from the Bug Creek Anthills locality. Scale bar equals 2 mm.

Figure 17. Centra of Acanthomorph indet. type HC-6, in anterior, left lateral, posterior, dorsal, and ventral views. A) UALVP 58835, from the Lance Formation; B) ROM 59160, from the Bug Creek Anthills locality; C) UCMP 198876/V73087, from the upper Hell Creek Formation. Fig. 14C from Brinkman et al. (2014:fig.15F). ScaleDraft bar equals 5 mm.

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Figure 18. Centra of teleost indet. type U-4, in anterior, left lateral, posterior, dorsal, and ventral views. A) UALVP 58847, from Lance Formation; B) UCMP 230627/V73087, from the upper Hell Creek Formation; C) TMP 2009.13.71, from the Scollard Formation; D) UCMP 297017/V99369, from lower Hell Creek Formation. Scale bar equals 2 mm.

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Figure 19. Centra of teleost indet. type RvB, in anterior, left lateral, posterior, dorsal, and ventral views. A) UCMP 198879, from Bug Creek Anthills locality; B) ROM 59133, from Bug Creek Anthills locality; C) UCMP 198879, from Bug Creek Anthills locality; D) UALVP 58848, from Lance Formation; E) UWBM 106400, from UWBM locality C1103 (Tuma), Hell Creek Formation. Scale bar equals 5 mm.

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Figure. 20. Higher-level taxonomic patterns of relative abundances of teleosts through the Hell Creek Formation, Garfield County, Montana, USA. Percent relative abundances are based on centra per locality (vertical stacked columns; see Table 2 for details), with each locality identified at the top of the figure and their total sample size (N) indicated in parentheses. MOR locality HC-656 was excluded due to low sample size (N=12). Taxa are listed at the right of the figure, with their total sample sizes (N) from these seven localities indicated in parentheses. The colorized box next to each taxon name corresponds to the colorized portions in the vertical stacked columns. The chronostratigraphic framework is based on Ar/Ar radiometric age determinations for the K/Pg boundary (†), age of the C30n/C29r geomagnetic polarity chron. boundary (‡), and an estimated age for the base of the Hell Creek Formation (*). See Sprain et al. (2018 and references therein) for details and age uncertainties. Abbreviations: Dan = Danian; FH = Fox Hills Formation; Fm = formation; FU = Ft. Union Formation; K/Pg = Cretaceous/Paleogene boundary; Ma = millions of years; Pg = Paleogene; Strat. (m) = stratigraphic height in meters below the Hell Creek/Ft. Union formational contact (~K/Pg boundary).

182x134mm (300 x 300 DPI)