PHYLOGENY, DIVERSITY, AND ECOLOGY OF THE AMMONOID SUPERFAMILY THROUGH THE AND

DAVID A.A. MERTZ

A Thesis

Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of

MASTER OF SCIENCE

August 2017

Committee:

Margaret Yacobucci, Advisor

Andrew Gregory

Keith Mann © 2017

David Mertz

All Rights Reserved iii ABSTRACT

Margaret Yacobucci

Both increased extinction and decreased origination, caused by rising oceanic anoxia and decreased provincialism, respectively, have been proposed as the cause of the Cenomanian

Turonian (C/T) extinction event for ammonoids. Conflicting evidence exists for whether diversity actually dropped across the C/T. This study used the ammonoid superfamily

Acanthoceratoidea as a proxy for ammonoids as a whole, particularly focusing on genera found in the Western Interior Seaway (WIS) of North America, including Texas. Ultimately, this study set out to determine 1) whether standing diversity decreased across the C/T boundary in the WIS,

2) whether decreased speciation or increased extinction in ammonoids led to a drop in diversity in the C/T extinction event, 3) how ecology of acanthoceratoid genera changed in relation to the

C/T extinction event, and 4) whether these ecological changes indicate rising anoxia as the cause of the extinction. In answering these questions, three phylogenetic analyses were run that recovered the families , , and .

Pseudotissotiidae was not recovered at all, while Coilopoceratidae was recovered but reclassified as a subfamily of Vascoceratidae. Seven genera were reclassified into new families and one genus into a new subfamily. After calibrating the trees with stratigraphy, I was able to determine that standing diversity dropped modestly across the C/T boundary and the Early/Middle

Turonian boundary. I also found an increase in the percentage of genera becoming extinct in the

Late Cenomanian, not a decrease in origination. Finally, I used Westermann morphospace to relate shell shape to ecology and mode of life. I found no decrease in morphospace occupation across the C/T boundary. More mobile modes of life expanded at this time. Morphospace iv iv occupation iv did drop across the Early/Middle Turonian boundary. All changes in morphospace occupation were driven by the family Vascoceratidae, suggesting this family was uniquely able to shift into novel modes of life in response to environmental change. v ACKNOWLEDGMENTS

I would like to thank Ann Molineux and the Non-vertebrate Paleontology Lab at the

University of Texas and Austin as well as Kathy Hollis and the National Museum of Natural

History for providing me access to fossil specimens in their care. I would also like to thank my committee, Margaret Yacobucci (Bowling Green State University), Andrew Gregory (Bowling

Green State University), and Keith Mann (Ohio Wesleyan University). Additionally, I would like to thank the Department of Geology at Bowling Green State University for their support and Bill

Butcher for help with various computer programs. Funding for this project was provided by

BGSU’s Richard D. Hoare Research Scholarship and the Geological Society of America

Graduate Student Research Grant Program. vi

TABLE OF CONTENTS

Page

INTRODUCTION………………………………………………………………………..... 1

Ammonoids During the C-T……………………… ...... 3

METHODS……………………………………………………… ...... 8

Phylogenetic Analysis…………………………………………...... 15

Standing Diversity ...... 18

Origination and Extinctions ...... 19

Westermann Morphospace ...... 19

RESULTS………………………...... 22

Phylogenetic Analysis……………………………………………………………….. 22

Proposed Reclasification……………………………...... 40

Standing Diversity……………………………………………………...... 43

Origination and Extinction…………………………………………………...... 43

Westermann Morphospace ...... 48

Familiy-Level Patterns ...... 48

Ecological Changes Through Time ...... 53

DISCUSSION……………………………...... 56

Phylogenetic Analysis……………………………………………………………….. 56

Pseudotissotiidae ...... 57

Micromorphs……………………………………………………...... 57

Standing Diversity ...... 58

Origination and Extinction ...... 58 vii

Westermann Morphospace ...... 59

Future Work ...... 60

CONCLUSIONS…………………………………………………………… ...... 62

REFERENCES……………………………………………………………………………… 64

APPENDIX A. CHARACTER LIST …………………………………………………… ... 69

APPENDIX B. DATA MATRIX FOR PHYLOGENETIC ANALYSIS……………… .... 93

APPENDIX C. OTHER PHYLOGENETIC ANALYSES ...... 94

APPENDIX D. RAW MEASUREMENTS ...... 97

APPENDIX E. STANDING DIVERSITY RAW VALUES ...... 98

APPENDIX F. ORIGINATION AND EXTINCTION PERCENTAGES ...... 99

APPENDIX G. NORMALIZED WESTERMANN MORPHOSPACE VALUES ...... 100

APPENDIX H. TUBERCLE AND SUTURE TERMS ...... 105

APPENDIX I. REFERENCES FOR TAXONOMIC DESCRIPTIONS ...... 106 viii

LIST OF FIGURES

Figure Page

1 Acanthoceratoid Stratigraphic Ranges ...... 4

2 Westermann Morphospace ...... 6

3 Dunveganoceras albertense ...... 9

4 Western Interior Seaway ...... 10

5 Superfamily Composition ...... 11

6 Westermann Morphospace Measurements ...... 21

7 Consensus Tree 1 ...... 24

8 Bootstrap and Jackknife Analysis 1 ...... 26

9 Calibrated Tree 1 ...... 29

10 Consensus Tree 2 ...... 31

11 Bootstrap and Jackknife Analysis 2 ...... 33

12 Calibrated Tree 2 ...... 35

13 Consensus Tree 3 ...... 36

14 Bootstrap and Jackknife Analysis 3 ...... 38

15 Calibrated Tree 3 ...... 41

16 Standing Diversity ...... 45

17 Origination and Extinction ...... 46

18 Westermann Morphospace for All Taxa ...... 49

19 Westermann Morphospace for Acanthoceratidae ...... 50

20 Westermann Morphospace for Collignoniceratidae ...... 51

21 Westermann Morphospace for Vascoceratidae ...... 52 ix

22 Westermann Morphospae Occupation Through Time ...... 54 x

LIST OF TABLES

Table Page

1 Acanthoceratoid Genera in the WIS ...... 13 1 INTRODUCTION

At the Cenomanian-Turonian (C/T) boundary (93.9 Ma), there was a major extinction event which has been cited as one of the ten largest mass extinctions of the Phanerozoic (Raup and Sepkoski, 1986). Elder (1989) reported that extinction among the ammonoids and inoceramid bivalves were the primary drivers of extinction patterns. Within ammonoids of the

Western Interior Seaway (WIS) of North America, up to 93% level extinction has been reported (Harries and Little, 1999). However, Monnet (2009) recently challenged whether there ever was an extinction among ammonoids within the WIS in the first place. In addition to the disagreement over the severity, or even the existence of the C/T extinction among ammonoids, different hypotheses for the cause of the extinction have been proposed. Specifically, Elder

(1989) proposed rising anoxia led to an increase in extinction. Alternatively, Monnet et al.

(2003) proposed that decreased provincialism due to rising sea level resulted in a decrease in speciation. This study aims to determine the severity and cause of the C/T extinction event among ammonoids.

The Cenomanian and Turonian Stages (89.8-100.5 Ma) of the Late were a time of global greenhouse warming. Atmospheric CO2 was as high as 1,120 ppmv and the average global surface temperature was around 21.5˚C (Poulsen et al., 2015), compared to 400 ppmv atmospheric CO2 and global average surface temperatures of 14.8˚C today (NOAA, 2016).

At the same time, global sea level was rising, reaching the highest level of the Phanerozoic right around the Cenomanian-Turonian (C/T) boundary (Hancock and Kauffman, 1979). Just before this sea level high, a global ocean anoxic event (OAE II) occurred (e.g., Arthur et al., 1987; Wan et al., 2003; Elderbak et al., 2014), evidenced by a major positive δ13C excursion and the 2 widespread marine deposition of laminated black shale (organic carbon rich layers). Both of which are indicative of anoxic conditions on the sea floor.

The current prevailing theory of the cause of OAE II is submarine volcanism triggered by large igneous provinces (Turgeon and Creaser, 2008). Prior to OAE II, Much of the oxygenated water in the Atlantic Ocean came from deep, polar derived water in the Pacific Ocean (DeBoer,

1986). As most submarine volcanism at the time was in shallow water (Kerr, 1998), there were likely major disruptions in ocean circulation, preventing the well oxygenated polar water from circulating to lower latitudes. This would result in increased anoxia in temperate regions (Kerr,

1998). Ocean anoxia would have been further exacerbated during the C/T interval because the ocean waters were warm; the solubility of oxygen decreases by 2% for each 1˚C increase in temperature (DeBoer, 1986), resulting in even more oxygen depleted waters. In addition, submarine volcanism would have released large quantities of CO2 as well as large amounts of

SO2, H2S, chlorine, and fluorine, leading to ocean acidification. This would result in the dissolution of much of the carbonates from this time period, releasing even more CO2 into the atmosphere, causing a runaway greenhouse effect (Kerr, 1998), and further reducing the oxygen in the water.

Often associated with OAE II is the Cenomanian-Turonian extinction event. The event affected both benthic and planktonic microorganisms (e.g., Wan et al., 2003; Elderbak et al.,

2014) as well as a variety of metazoans (e.g., Elder, 1989; Sepkoski, 1989; Harries and Little,

1999). For marine metazoans, Sepkoski (1989) reported 8% family-level, 26% genus-level, and

33-53% species-level extinctions. The majority of the observed extinction pattern appears to be driven by extinctions in mollusks, primarily ammonoids and inoceramid bivalves (Elder, 1989).

The C/T extinction has frequently been reported as stepwise, instead of a single event (e.g., 3 Cobban and Scott, 1972; Elder, 1989; Kaiho et al, 2014), as extinctions appear as a series of discrete, short-term, global events spread out over 1.46 m.y. (Kauffman, 1988).

Ammonoids during the C-T

During the C-T interval, ammonoid were a widespread and diverse group.

Within this time period, Superfamily Acanthoceratoidea was the biggest driver of global trends, such as turnover rates and paleolatitudinal distributions (Monnet et al., 2003; Monnet, 2009;

Yacobucci, 2017). Globally, there is a large turnover of acanthoceratoid genera around the C/T boundary. Many acanthoceratoid genera do not cross the boundary, and four major families are first seen during this time period: Vascoceratidae, Pseudotissotiidae, Collignoniceratidae, and

Coilopoceratidae (Figure 1; Wright et al., 1996).

Monnet and colleagues have published several studies documenting overall species richness and turnover rates of ammonoids leading up to the C/T boundary and into the Early

Turonian (Monnet et al., 2003; Monnet and Bucher, 2007; Monnet, 2009). These studies focused on Europe, , and the Western Interior Seaway (WIS) of North America. In Europe, they found that species richness gradually decreased starting near the Middle-Upper Cenomanian boundary, as opposed to abruptly decreasing during OAE II (Monnet et al., 2003; Monnet,

2009). In Tunisia, species richness actually increased throughout OAE II, and in the WIS, species richness fluctuated with no apparent temporal pattern (Monnet, 2009). Conversely, others have reported very high levels of ammonoid extinction across the C/T boundary within the WIS.

For example, in ammonoids, Elder (1989) reported 81% species level extinction and Harries and

Little (1999) reported 93% species level extinction during OAE II.

In order to resolve these discrepancies in the inferred scale of the ammonoid turnover during the C/T interval, one first needs a phylogenetic framework for the clades involved. A 4

Figure 1. Acanthoceratoid Stratigraphic Ranges. Stratigraphic ranges for the families Acanthoceratidae, Vascoceratidae, Pseudotissotiidae, and Collignoniceratidae through the Cenomanian and the Turonian. 5 phylogenetic approach allows for more accurate evaluations of standing diversity and the overall numbers of extinctions and originations through time by including inferred range extensions. In this study, I aimed to conduct phylogenetic analyses of Cenomanian-Turonian ammonoids within the WIS as a first step in better understanding the nature of this turnover event.

In addition to disagreements about the severity of the C/T extinction for ammonoids, differing causes of the turnover have also been suggested. Elder (1989) proposed that ocean anoxia began in deeper waters and gradually rose into the water column and farther onshore, creating a stepwise extinction event. Monnet and Bucher (2007), however, found that pelagic heteromorphs became extinct before the nektobenthic acanthoceratids, implying that a rising oxygen minimum zone cannot have been the cause of the extinction. Instead of ocean anoxia,

Monnet et al. (2003) proposed that rising sea levels in the Middle Cenomanian led to a decrease in provincialism, resulting in decreased speciation rates. They argued that it was decreased speciation rates, not increased extinction, that caused the observed diversity drop.

One way to test potential causes of the C/T turnover is through the use of Westermann morphospace (Westermann, 1996). Westermann (1996) created a theoretical morphospace for planispiral ammonoid shells that quantifies visible external shell shape (Figure 2a). He also theorized different modes of life based on the shell shape (Figure 2b). These modes include demersal (living close to the sea floor), nektonic (active swimmers), planktonic (free floating, mostly inactive), and vertical migrants (rise through the water column at night to feed).

Ritterbush and Bottjer (2012) later quantified the morphospace in an attempt to divide quantitatively similar specimens into the hypothetical guilds defined by Westermann (1996). By creating a morphospace for each substage from the Middle Cenomanian through the Upper

Turonian (Cobban et al., 2006), it is possible to compare morphospace occupation through time 6 rofile he he p

of the out shell. Modified from Westermann (1996). b) Hypothetical modes of life superimposed on Westermann morphospace. Westermann on superimposed Hypothetical life of b) of modes from the shell. (1996). Westermann out Modified plot Specimens (2012). and on shell inflation and Bottjer based umbilicus, expansion. exposure of whorl From Ritterbush Figure 2. Westermann Morphospace. a) Morphospace displaying common ammonoid planispiral shell shapes gradingdisplaying common Figure three ammonoidshell between shapes d a)en Morphospace. planispiral 2. Westermann Morphospace through section whorls forms:illustration on superimposed Each the and t a contains oxycone. serpenticone, cross spherocone, 7 in order to determine which modes of life preferentially survived the Cenomanian-Turonian extinction. If anoxia did indeed rise through the water column, we should see the demersal and possibly the vertical migrant portions of the morphospace become emptied across the C/T boundary, because these modes of life would be most vulnerable to benthic anoxia. It is also likely we would see a shift towards more active modes of life (i.e., nektonic), because active swimmers could potentially swim away from anoxic conditions.

For this thesis, I focus on four primary questions about ammonoid diversity within the

Western Interior Seaway: 1) Is there a decrease in standing ammonoid diversity across the C/T boundary? 2) Was it decreased speciation, increased extinction, or a combination of the two processes that led to a drop in ammonoid diversity across the putative C/T extinction event? 3)

How did the life modes of acanthoceratoid genera change in relation to the C/T extinction event?

4) Do these changes in life mode indicate that rising anoxia was the cause of the extinction? 8 METHODS

To address these questions, binned the two stages into substages, starting in the Middle

Cenomanian and continuing through the Late Turonian. I also focused solely on the ammonoid superfamily Acanthoceratoidea (Figure 3) in the Western Interior Seaway of North America including Texas (Figure 4). Members of this superfamily make up approximately 75% of the species present in the WIS (Figure 5; Monnet, 2009) and are the main drivers for major ammonoid trends worldwide (Monnet et al., 2003; Monnet, 2009; Yacobucci, 2017). As a result, acanthoceratoid ammonoids are a good proxy for ammonoid diversity during the interval as a whole.

I focused on the acanthoceratoid genera of the WIS for two reasons: 1) The Late

Cenomanian was a complex time ecologically, with very high temperatures, CO2 levels, rising sea levels, and each region experienced anoxia and extinction at different times. Pooling all regions together will provide a global view of what was happening, but sacrifices the ability to disentangle detailed patterns which may emerge when looking at a smaller region. By focusing solely on the WIS, I will be able to get a clearer picture of the nature of the extinction event in one particular region. 2) Including every C-T ammonoid genus is simply not feasible for a study of this scope. There is limited access to taxa that are exclusively in the Pacific or south Atlantic

(Japan, New Zealand, Venezuela, etc.) without traveling to each country. While one could obtain data through an analysis of the literature, there would still be a substantially large bias toward

WIS genera, which are better documented and more easily accessible to a North American worker. 9

Figure 3. Dunveganoceras albertense. A typical acanthoceratoid specimen displaying prominent ornamentation. USNM 108327a. 10

Figure 4. Western Interior Seaway. Map showing the extent of the Western Interior Seaway of North America during the Cenomanian-Turonian interval. From Macroevolution.net (http://www.macroevolution.net/cretaceous-western-interior-seaway.html) 11

Figure 5. Superfamily Composition. Graphical representation of species present in the Western Interior Seaway during the Middle Cenomanian through the Early Turonian by superfamily. Numbers from Monnet, 2009.

12 Using only WIS genera from the Middle Cenomanian through the Turonian initially resulted in the inclusion of 60 genera (Table 1), with Stoliczkaia, Mantelliceras, , and Sharpeiceras initially included as outgroups. Eleven taxa are micromorphic, that is, very small ammonoids that likely evolved through progenesis, that is, precocious sexual maturation, resulting in juvenile traits of ancestral taxa appearing in adults of the micromorphic taxa. This lowered the resolution of the phylogenetic analyses, so they were not included in the final analyses. Several additional taxa, including the outgroups Acompsoceras and Sharpeiceras, were not well represented in available collections and were removed from the subsequent analyses

(Table 1).

I collected data on ammonoid morphology from the National Museum of Natural History

(NMNH) in Washington D.C. and the Non-Vertebrate Paleontology Lab at the University of

Texas at Austin. NMNH was used because that is where all holotypes found in the U.S. by the

U.S. Geological Survey (USGS) are housed. Specimens at the Non-vertebrate Paleontology Lab were used to supplement the specimens at the NMNH because, historically, specimens collected in Texas were collected by the Texas Bureau of Economic Geology, not the USGS. In total, 607 specimens were examined for use in these analyses. 13 Genera First Appearance Datum Last Appearance Datum PHYLOGENETIC ANALYSIS Acanthoceratidae Early Cenomanian Late Cenomanian Early Cenomanian Late Cenomanian Middle Cenomanian Middle Cenomanian Middle Cenomanian Middle Cenomanian Dunveganoceras Middle Cenomanian Late Cenomanian Middle Cenomanian Late Cenomanian Paraconlinoceras Middle Cenomanian Middle Cenomanian Plesiacanthoceras Middle Cenomanian Late Cenomanian Tarrantoceras Middle Cenomanian Middle Cenomanian Late Cenomanian Late Cenomanian Late Cenomanian Late Cenomanian Nigericeras Late Cenomanian Late Cenomanian Late Cenomanian Early Turonian Pseudocalycoceras Late Cenomanian Late Cenomanian Sumitomoceras Late Cenomanian Late Cenomanian Early Turonian Early Turonian Early Turonian Late Turonian Morrowites Early Turonian Early Turonian Pseudaspidoceras Early Turonian Middle Turonian Early Turonian Late Turonian Spathites Early Turonian Late Turonian Early Turonian Early Turonian Vascoceratidae Rubroceras Late Cenomanian Late Cenomanian Late Cenomanian Early Turonian Early Turonian Early Turonian Infabricaticeras Early Turonian Early Turonian Vascoceras Late Cenomanian Early Turonian Pseudotissotiidae Choffaticeras Early Turonian Early Turonian Hourcqia Late Turonian Late Turonian Collignoniceratidae Cibolaites Late Cenomanian Late Turonian Early Turonian Late Turonian Prionocyclus Middle Turonian Middle Turonian Late Turonian Late Turonian Coilopoceratidae Early Turonian Early Turonian Middle Turonian Late Turonian GENERA NOT INCLUDED IN 14 PHYLOGENETIC ANALYSES Acanthoceratidae Alzadites* Middle Cenomanian Late Cenomanian Kastanoceras* Middle Cenomanian Middle Cenomanian Plesiacanthoceratoides* Middle Cenomanian Late Cenomanian Buccinammonites* Late Cenomanian Late Cenomanian Burroceras Late Cenomanian Late Cenomanian Cryptometoicoceras* Late Cenomanian Late Cenomanian Microsulcatoceras* Late Cenomanian Late Cenomanian Nannometoicoceras* Late Cenomanian Late Cenomanian Paraburroceras* Late Cenomanian Late Cenomanian Paracompsocers Late Cenomanian Late Cenomanian Thomelites Late Cenomanian Early Turonian Quitmaniceras Early Turonian Early Turonian Rhamphidoceras* Early Turonian Early Turonian Nebraskites Middle Turonian Middle Turonian Vascoceratidae Microdiphasoceras* Late Cenomanian Late Cenomanian Pseudotissotiidae Pseudotissotia Early Turonian Middle Turonian Thomasites Early Turonian Early Turonian Wrightoceras Early Turonian Middle Turonian Collignoniceratidae Prionocyclites* Middle Turonian Middle Turonian Reesidites Early Turonian Early Turonian Forbesiceratidae Forbesiceras Early Cenomanian Late Cenomanian

Table 1. Acanthoceratoid Genera in the WIS. A list of acanthoceratoid genera in the Western Interior Seaway of North America from the Middle Cenomanian through the Upper Turonian and the range of each genus. Table is divided by taxa included in the phylogenetic analysis and taxa included in all other analyses. Taxa are organized by family and then in stratigraphically, with the outgroups appearing first. The symbol * indicates a micromorphic genus. 15 Phylogenetic Analysis

For the phylogenetic analysis I used both parsimony and stratigraphic congruence.

Parsimony was used because it is the method most commonly used by paleontologists (e.g.,

Yacobucci, 1999; Monks, 2000; McGowan and Smith, 2007; Scott et al. 2010), and aims to find the shortest trees possible (i.e., the ones requiring the fewest character state changes) based on a character matrix. Stratigraphic congruence was used because it provides a way to examine how well the phylogenetic analyses match stratigraphy. Ammonoids display a high degree of homeomorphy, convergent character states, so examining stratigraphic congruence is an effective way to identify problematic taxa for removal in future analyses. Using these criteria, I conducted three phylogenetic analyses.

For each analysis, character matrix included 50 characters (see appendices). The characters were defined based on previous literature (Yacobucci, 2012), taxonomic descriptions of included genera (see Appendix I) and observations of fossil specimens. In total, there were 10 shell shape characters, 20 ornamentation characters, and 20 suture characters. All characters were discretely coded and unweighted. Except for whorl section shape (character 7), shell shape characters included both adult and juvenile specimens. Ornament characters were divided into adult and juvenile characters. Lateral tubercles, both adult and juvenile, were not included in this study, because they are only present on Romaniceras. Due to the way sutures change through ontogeny, gradually becoming more complex through time, only adult sutures (signified by a decrease in spacing between sutures) were examined. For all measurements except ventral width, measurements were taken on museum specimens. Ventral width measurements were taken photographs of museum specimens. For continuous variable characters (e.g., whorl expansion rate, lateral saddle height/width), multiple specimens for each genus were measured and a mean 16 value was calculated from these values. Initially, decided gaps based on standardized pooled variance were used to define these characters, however, this resulted in almost every taxon having an autapomorphy, so decided gaps were not used for coding. Instead, I used a qualitative approach, looking for relatively large gaps in order to bin the continuous characters. Several characters that are potentially phylogenetically informative were excluded due to lack of data, including body chamber length, relative timing of ontogenetic changes in shape and ornamentation, and embryonic data.

In the first analysis, 6.2% of character states were coded as missing, and in the second and third analyses, 4.9% of character states were coded as missing. The majority of characters could be coded for all or nearly all taxa. Characters that involve the external saddle of the suture consistently had more taxa than could not be coded. This is because in many of the taxa, while the suture was preserved, the external saddle was not. Ventral width/diameter (character 8) also had a large number of taxa that could not be coded, because the ventral shoulder cannot be identified in all taxa. Most taxa have minimal missing data, however, Infabricaticeras,

Kamerunoceras, Nigericeras, and Watinoceras have 9 (18%), 11 (22%), 9 (18%), and 12 (24%) characters missing. Infabricaticeras, Kamerunoceras, and Watinoceras were all removed in the second and third analyses. Nigericeras was used in all three analyses, but its classification cannot be determined based on available data (see Results), potentially due to the large number of characters it is missing.

For each genus I used a single exemplar species, chosen because it had the largest number of well-preserved specimens available. I used genera as opposed to species, because genera are more taxonomically stable than species in the fossil record and are thus more reliable estimators of diversity through time (Crampton et al., 2006). Additionally, a phylogenetic 17 analysis at the species level would yield spurious results due to the high degree of homoplasy in ammonoids. I analyzed the matrix using the software package PAUP (Swofford, 2003), using a heuristic search to find the most parsimonious, or shortest, trees (MPTs). The addition sequence was set to random and each run went through 1,000 replicates.

Early on, it became clear that the taxa initial outgroups, Stoliczkaia and Mantelliceras, were not suitable. With both or either set to the outgroup, large stratigraphic incongruences emerged, indicating that the character transformations were incorrectly polarized when these outgroups were used. Changing the outgroup to Acanthoceras reduced stratigraphic incongruence and increased resolution of the consensus tree.

In total, I ran three different phylogenetic analyses. The first analysis included 35 taxa

(Table 1). In the second analysis, I removed all taxa with a range extension greater than a single substage, as determined by the first analysis, due to high stratigraphic incongruence. This resulted in the removal of six taxa: Infabricaticeras, Kamerunoceras, Mammites, Romaniceras,

Spathites, and Watinoceras. The third analysis excluded Pseudaspidoceras in addition to those removed in the second analysis. Analyses were also run removing Nigericeras and Morrowites, however, these deletions did not cause significant changes in the tree topology (See Appendix

C).

After each analysis in PAUP, a 50% majority rule consensus tree was generated showing each node that appears on 50% or more of the shortest recovered trees. If a node appears on less than 50% of all MPTs, it collapses into a polytomy. To assess support for subclades, I ran bootstrap and jackknife analyses in PAUP. Bootstrapping keeps the same total number of characters in each test, but within each run certain characters may be included more than once or not at all. Jackknifing runs the analysis again, but using a random selection of 50% of the total 18 characters. In both analyses, a heuristic search was used, the number of replicates (nreps) was set to 100, and the consensus level was set to 50%.

For each phylogenetic analysis, I incorporated observed stratigraphic ranges into a calibrated evolutionary tree allowing for the examination of stratigraphic congruence, or how well the reconstructed phylogeny matches with known fossil stratigraphy. To create a calibrated evolutionary tree, range extensions, a stratigraphic interval in which a taxon should have existed according to the cladogram but does not appear in the known fossil record, and ghost lineages, stratigraphic intervals where a taxon that does not appear in the fossil record must have existed according to the cladogram, must be created. Range extensions are created by extending the first appearance datum for a taxon down to the first appearance of its sister group. Ghost ranges are created by adding a hypothetical taxon from the base of a clade to the first appearance of a sister clade. By using the calibrated trees, I was able to determine how well the reconstructed phylogeny matched known stratigraphy by assessing the number and length of range extensions.

Standing Diversity

Two different counts of standing diversity were taken based on each calibrated evolutionary tree. Standing diversity is a count of all genera present within a given time interval,

The first count of standing diversity only included taxa used in the phylogenetic analysis, while the second count included all those genera plus all genera known to be present at that time but not used in the phylogenetic analysis due to a lack of data (Table 1). Counts including and excluding range extensions are provided. Ghost lineages were not included, because of the way phylogenetic trees are generated. Parsimony analysis does not allow one taxon to directly evolve from another taxon, but requires the inference of an unrecorded common ancestor to each sister taxon pair, creating a ghost lineage that may or may not have actually existed. 19 Origination and Extinction

Within each substage, the number of genus-level originations and extinctions were expressed as a percentage of the total number of genera present within that substage. Origination percentages were calculated by dividing the total number of taxa originating in the substage by the total number of taxa present. Extinctions were calculated by dividing the number of taxa that became extinct during a substage by the total number of taxa present. Percentages were determined both with and without range extensions for all three calibrated evolutionary trees.

Westermann Morphospace

In order to determine mode of life, I conducted an analysis using Westermann morphospace, based on both Westermann (1996) and Ritterbush and Bottjer (2012). In total, 214 specimens were suitable for inclusion, including acanthoceratoid genera not included in the phylogenetic analyses (see Appendix G). Shell measurements for the analysis include the umbilical diameter (UD), total diameter (D), aperture width (b) and height (a), and aperture height at the previous half whorl (a'; Figure 6). Instead of using these raw measurements, they were combined into ratios (eq. 1, eq. 2, eq. 3). Ratios remove size from the analysis, so that only shape is expressed.

U = UD/D eq. 1

Th = b/D eq. 2

w = a/a’ eq. 3

In Westermann morphospace, each end member, serpenticone, spherocone, and oxycone, maximizes parameters for the umbilicus (U), shell inflation (Th), and expansion rate (w), 20 respectively. Before I plotted the measurements in Westermann’s ternary diagram, however, the data were standardized using the minimum and maximum values for all ammonoids (eq. 4), as calculated by Ritterbush and Bottjer (2012); otherwise all of the data will plot towards w, because it is consistently the largest value. Using the minimum and maximum values for all ammonoids allows a comparison of my data with those from any future study using Westermann morphospace.

N’ = (n – min)/(max-min) eq. 4

Two different plots with all specimens were generated: one with the traditional taxonomic classifications and one with the new classifications proposed here. I also created plots for each family, highlighting where they fall within the plot. I then created a morphospace for each substage to show how occupation changed through time, which was then interpreted based on known environmental conditions (e.g., rising sea level, ocean anoxia). Each morphospace was generated in PAST (Hammer et al., 2001). 21

Figure 6. Westermann Morphospace Measurements. Illustration of measurements of an ammonoid fossil shown in cross section. Modified from Ritterbush and Bottjer (2012) 22 RESULTS

Phylogenetic Analysis

Using the final 35 taxa (Table 1), a total of 154 MPTs with a tree length of 426 were recovered. The consistency index CI (0.3803), retention index RI (0.4545), and rescaled consistency index RC (0.1729) are all low, however, this is not surprising given how quickly the group has been shown to evolve (Yacobucci, 1999). High rates of evolution makes it more likely for character traits to evolve more than once, leading to a higher degree of homoplasy. The 50% majority rule consensus tree, Consensus Tree 1, is shown in Figure 7. The consensus tree can broadly be divided into two main sister clades (Clade B + Clade B-morphs and Clade C) with a smaller basal clade (Clade A) containing Nigericeras, Morrowites, and Pseudaspidoceras, just above Acanthoceras and Cunningtoniceras (Figure 7).

Clade A is unified by the absence of dimorphism, moderately small rib spacing, a unifid lateral (L) saddle, and an elongated L saddle. Clade A is placed just above Cunningtoniceras because of the absence of symmetry in the L saddle, an elongated U saddle, and a moderately high external (E) saddle height to L saddle height, all of which are derived characters shared with

Cunningtoniceras. The placement for this group, however, does not seem likely due to its movement in later analyses and the large number of characters missing from Nigericeras.

Clade B + the Clade B-morphs contains all taxa present within Vascoceratidae and

Coilopoceratidae as well as Choffaticeras (Pseudotissotiidae) and several taxa traditionally assigned to Acanthoceratidae (Calycoceras, Dunveganoceras, Mammites, Spathites). Of particular note within Clade B are Calycoceras and . Instead of falling with the other acanthoceratids, Calycoceras falls well within the clade with vascoceratid genera.

Neoptychites (Vascoceratidae), while still falling close to other vascoceratid genera, sits within a 23 subclade clade with Choffaticeras, Hoplitoides, and Coilopoceras. Clade B is defined by high involution, high shell inflation, high overlap with the previous whorl, the absence of inner ventrolateral (IVL) tubercles, a central location for the deepest element on the first U saddle, and the absence of skew of the L saddle. Both Mammites and Dunveganoceras are included as Clade-

B morphs by the absence of a juvenile ventral tubercle and the umbilical tubercle being the juvenile’s most prominent tubercle. Rubroceras and Mammites are united by the presence of bullate IVL tubercles. The lack of other characters uniting Rubroceras to the rest of Clade B +

Clade B-morphs makes me question its location on the tree.

Clade B can be further divided into two subclades, Clade B’ and Clade B”. Clade B’ consists of Calycoceras, Infabricaticeras, Vascoceras, and Fagesia, while Clade B” includes

Neoptychites, Choffaticeras, Hoplitoides, and Coilopoceras. Clade B’ is defined by a moderate aperture overlap, the presence of bullate adult umbilical tubercles, the umbilical tubercle being the adult’s most prominent tubercle, and the absence of a prominent element in the first U saddle.

Clade B” is defined by large apertural overlap, a lanceolate whorl section, the absence of any adult prominent tubercle, the absence of a juvenile umbilical tubercle, and the deepest element located centrally on the first U saddle. Clade B” is supported by both jackknife and bootstrap analyses (Figure 8). 24

Figure 7. Consensus Tree 1. 50% majority rule consensus tree of all 154 MPTs with all taxa included. Color around the genus name indicates the traditional classification. Solid color square indicates the proposed reclassification. 25 The final clade, Clade C, is predominantly made up of taxa traditionally assigned to

Acanthoceratidae and Collignoniceratidae along with Hourcqia (Pseudotissotiidae). The defining features of Clade C include the presence of an adult ventral tubercle, absence of an adult IVL tubercle, presence of an adult outer ventrolateral (OVL) tubercle, and the OVL tubercle being the most prominent juvenile tubercle. While Clade C is comprised of two smaller groups, it is not worth defining each group individually due to the many stratigraphic incongruences (Figure 9) and the breakdown of the two groups in subsequent analyses. Two groupings, Collignoniceras and Prionocyclus and Hourcqia and Barroisiceras, are both supported by a bootsrap analysis and a grouping of Hourcqia and Barroisiceras is supported by a jackknife analysis.

When examining the tree for stratigraphic congruence, 13 out of 35 taxa (37%) have a range extension of at least one substage, 6 (17%) of which have a range extension of two substages (Figure 9). Many of the single substage range extensions are reconcilable because of how I binned time. If a taxon appears in a specific substage, I assumed that it was present through the entire substage, which I know to sometimes be false. Vascoceras, for instance, only appears in the latest Cenomanian, not the beginning of the Late Cenomanian substage, so the range extension for Fagesia is likely not the length of the entire Late Cenomanian, but only extends into the latest Cenomanian. 26 a) 27 b)

Figure 8. Bootstrap and Jackknife Analysis 1. A 50% majority rule consensus tree for a) bootstrap and b) jackknife analyses. Colors same as for Figure 7.

28 In an attempt to create a more stratigraphically congruent tree, a second analysis was run excluding all taxa with a range extension greater than one substage. Excluded taxa included

Mammites, Romaniceras, Spathites, Infabricaticeras, Watinoceras, and Kamerunoceras. With these six taxa removed, 37 MPTs with a tree length of 358 were recovered. CI (0.4385), RI

(0.4752), and RC (0.2084) are all marginally better than those in the first analysis, but are still low. The consensus tree, Consensus Tree 2, is shown in Figure 10. Removing the stratigraphically incongruent taxa resulted in three major clades (Clade D, Clade F, and Clade B) and a smaller clade, Clade E, consisting of just Euomphaloceras and Rubroceras (Figure 10).

Clade A also moved to the base of Clade B.

All taxa within Clade D, which closely matches evolutionary relationships previously postulated in the literature (Wright et al., 1996), were a part of Clade C in Consensus Tree 1

(Figure 7). Plesiacanthoceras and Watinoceras now sit toward the base of the clade and

Tarrantoceras, Eucalycoceras, and Pseudocalycoceras have all shifted to the top of the tree.

Paraconlinoceras now sits directly after Conlinoceras, from which it is believed to be derived

(Wright et al., 1996). The characters that unite this group are all suture characters: complex sutures, a unifid external (E) saddle, an elongated first U saddle, and a dorsal skew of the L saddle.

Clade E, which shares a polytomy with Clades F and B, consists solely of

Euomphaloceras and Rubroceras. In Consensus Tree 1 (Figure 7), Euomphaloceras was allied to

Paraconlinoceras, but it has now shifted next to Rubroceras, forming their own clade. They are united by the absence of a juvenile ventral tubercle, a unifid L saddle, a rounded L saddle, and the deepest element of the L saddle positioned dorsally. 29

Figure 9. Calibrated Tree 1. Consensus Tree 1 calibrated with stratigraphy in order to show range extensions (red dashed lines) and ghost lineages (black dashed lines). Colors same as for Figure 7. 30 Clade F consists of all taxa classically assigned to Collignoniceratidae plus

Neocardioceras (Acanthoceratidae) and Hourcqia (Pseudotissotiidae). In Consensus Tree 1

(Figure 7), all included taxa were present in Clade C, however, they were divided between the two subgroups of Clade C, Neocardioceras, Cibolaites, Hourcqia, and Barroisiceras on one side, and Prionocyclus and Collignoniceras on the other. Removing the taxa with large range extensions brought the two groups together into a new clade, Clade F, which shifted away from the taxa in Clade C and toward the taxa in Clade B (Figure 10). This clade is defined by the presence of a keel, a clavate adult ventral tubercle, the ventral tubercle being the juvenile’s most prominent tubercle, a unifid lateral lobe, and a small first U saddle compared to the L saddle.

Clade F is also closely related to the taxa in Clade E, forming a larger clade, Clade E+F, defined by a clavate juvenile IVL tubercle and a rounded first U saddle.

Clade B is the only clade retained from Consensus Tree 1, although the topology of the group has changed (Figure 10). With the six taxa removed, Fagesia is now more closely aligned to

Calycoceras instead of Vascoceras. With the removal of the six taxa, Clade B is now largely defined by the presence and type of juvenile tubercles as well as the absence of an adult ventral tubercle. Clades B’ and B” both survive, with the same defining characteristics as in the first analysis. The movement of Clade A from the base of the tree to the base of Clade B is due to the lack of migration of the umbilical tubercle, an elongated L saddle, and an elongated first U saddle.

Bootstrap and jackknife tests indicate support for Vascoceratidae as a whole, with stronger support for subfamily Coilopoceratinae (Figure 11 a, b). In both tests, clades containing

Hourcqia and Barroisiceras and Collignoniceras and Prionocyclus are recovered, although are not supported as strongly as Vascoceratidae and Coilopoceratinae. 31

Figure 10. Consensus Tree 2. 50% majority rule consensus tree of all 37 MPTs with all taxa with range extensions longer than one substage removed. Color around the genus name indicates the traditional classification. Solid color square indicates the proposed reclassification. 32 When examining this tree for stratigraphic congruence (Figure 12), there are far fewer range extensions than when all taxa are included (Figure 9). The range extension for Vascoceras is likely not realistic because it is greater than two substages, since Calycoceras extends into the

Early Cenomanian. It is more likely that the presence of Clade A is causing a change in the polarity of characters 36, 39, and 40, pulling Vascoceras lower on the tree.

The range extensions that appear to cause the most changes to the topology of the tree are related to the three taxa in Clade A. Therefore, further analyses were run excluding Clade A as a whole and then removing the taxa individually. Removing Clade A and Nigericeras and

Morrowites individually only resulted in minor topology changes (See Appendix C). Removing just Pseudaspidoceras, on the other hand, caused several significant changes in the topology of the tree (Figure 13).

With Pseudaspidoceras removed in addition to the taxa removed in the second analysis,

231 MPTs of length 347 were recovered. Descriptive statistics for these 231 trees are similar to the values obtained in the second analysis: CI=0.4524, RI=0.4780, and RC=0.2163 (Figure 13

Consensus Tree 3). Bootstrapping and jackknifing provide strong support for subfamily

Coilopoceratinae and mild support for groupings of Hourcqia + Barroisiceras and

Collignoniceras + Prionocyclus (Figure 14 a, b).

All clades in the previous analysis have survived, although there are several small topology changes and Dunveganoceras and Cunningtoniceras both change clades. Additionally,

Clade E and Clade F, now group together with Clade D instead of Clade B. 33 a) 34 b)

Figure 11. Bootstrap and Jackknife Analysis 2. A 50% majority rule consensus tree for a) bootstrap and b) jackknife analyses. Colors same as for Figure 7. 35

Figure 12. Calibrated Tree 2. Consensus Tree 2 calibrated with stratigraphy in order to show range extensions (red dashed lines) and ghost lineages (black dashed lines). Colors same as for Figure 7. 36

Figure 13. Consensus Tree 3. 50% majority rule consensus tree of all 231 MPTs with Pseudaspidoceras removed in addition to taxa removed in the second analysis. Color around the genus name indicates the traditional classification. Solid color square indicates the proposed reclassification. 37 Within Clade A+B, Dunveganoceras is no longer included. Instead, Cunningtoniceras is the root of the clade, united by a nodate or bullate umbilical and a nodate or clavate OVL tubercle in juveniles. These characters, however, are only shared with Nigericeras. Because

Cunningtoniceras does not share any characters with the rest of Clade A+B, it is unlikely that

Cunningtoniceras belongs at the base of this clade. For the rest of Clade A+B, Nigericeras and

Morrowites have switched places due to the characters Nigericeras shares with

Cunningtoniceras. Fagesia also now sits below both Calycoceras and Vascoceras, owing to

Nigericeras and Morrowites changing places. While the taxa in Clade B’ and B” still fall next to each other, the subclades are no longer differentiated. Instead they branch in stepwise fashion.

Within Clade D, the topology has not changed, except Dunveganoceras is now grouped with Metoicoceras and Plesiacanthoceras, which is its traditional placement (Cobban, 1987).

This subgroup is defined by the absence of a juvenile ventral tubercle and a unifid L lobe.

Dunveganoceras also pairs with Plesiacanthoceras because of a lack of dimorphism. This grouping makes more sense than in the previous analyses because of where the taxa are found.

Dunveganoceras is found exclusively in the northern WIS and Plesiacanthoceras and

Metoicoceras are both endemic to the WIS. The majority of taxa in Clade B, on the other hand, are found throughout the Tethys Ocean. Without a northern connection between the WIS and the

Tethys Ocean, which has been suggested, but never confirmed, (Yacobucci, personal communication, 2017), it would be difficult for Dunveganoceras to give rise to the rest of the group. 38 a) 39 b)

Figure 14. Bootstrap and Jackknife Analysis 3. A 50% majority rule consensus tree for a) bootstrap and b) jackknife analyses. Colors same as for Figure 7. 40 The internal topology of Clades E and F have not changed, however, they are now on a different portion of the tree. Whereas before Clades E and F were more closely related to Clade

A+B (Figure 10), they are now more closely related to Clade D, owing to a round whorl section, rib density, the presence of a bullate adult IVL tubercle, and the absence of an adult OVL tubercle.

All changes to tree topology in the third analysis were caused by the removal of

Pseudaspidoceras. This is largely owing to this genus having a clavate juvenile IVL tubercle and a symmetrical U saddle. These characters in Pseudaspidoceras were enough to pull

Dunveganoceras and Clades E and F away from Clade A+B and towards Clade D.

When I tested for stratigraphic congruence (Figure 15), the results are largely similar to the previous analysis (Figure 12) with only two differences. One is the loss of the range extension attached to Vascoceras. The second difference is that there is no longer a large ghost lineage at the base of Clade B”. Since clades B’ and B” are no longer differentiated, the ghost lineage below Choffaticeras has been cut in half. Overall, this tree has the greatest stratigraphic congruence of the three analyses.

Proposed Reclassifications

In total, it is proposed that eight genera be reclassified as a result of this study. Spathites,

Calycoceras, Choffaticeras, Coilopoceras, and Hoplitoides are all reclassified as a part of

Vascoceratidae with Calycoceras belonging to subfamily Vascoceratinae and Choffaticeras 41

Figure 15. Calibrated Tree 3. Consensus Tree 3 calibrated with stratigraphy in order to show range extensions (red dashed lines) and ghost lineages (black dashed lines). Colors same as for Figure 7. 42 and Coilopoceras belonging to subfamily Coilopoceratinae. Even though Spathites only appears in the first analysis, the high number of characters it shares with other vascoceratid taxa (low degree of involution, high shell inflation, high apertural overlap with the previous whorl, the absence of an IVL tubercle, and the absence of skew in the lateral saddle) are enough to reclassify it within Vascoceratidae. There is not currently enough information to place Spathites with confidence in either subfamily. Neoptychites stays within Vascoceratidae, but has moved to subfamily Coilopoceratinae. Neocardioceras and Hourcqia are both reassigned to

Collignoniceratidae.

Several taxa cannot be classified based on the current results. Mammites’ surprising placement at the base of Vascoceratidae and its subsequent removal from the study makes it currently impossible to classify. With Dunveganoceras falling at the base of Vascoceratidae

(Figures 7 and 10) and within Acanthoceratidae (Figure 13) in different analyses, it cannot currently be placed into either group. Nigericeras, Morrowites, and Pseudaspidoceras do not appear to fit within any established group, although they are potentially allied with

Vascoceratidae. The three taxa consistently group near each other, but the large stratigraphic incongruence associated with them and their placement in the first analysis makes me hesitant to assign them to any currently erected group. Euomphaloceras and Rubroceras, Clade E, are two more taxa that do not appear to fall into any established group. In all three phylogenetic analyses, they fall in different locations, in one not even grouping together. Based on their strong support in Consensus Trees 2 and 3 (Figures 10 and 13), Euomphaloceras and Rubroceras likely form a clade, however, they cannot currently be placed into any existing group. 43 Standing Diversity

Standing diversity is shown in Figure 16. Two different diversities are shown: 1) the total number of genera found in the fossil record during that substage and included in the calibrated tree and 2) all included genera plus genera known to have been present but removed from the phylogenetic analysis. Removed taxa include all micromorphs and taxa with insufficient data to be included in the phylogenetic analysis. Standing diversity is presented both with and without range extensions. The overall pattern in both plots shows a drop in diversity across the C/T boundary as well as a second, potentially larger drop across the Early/Middle Turonian boundary.

Origination and Extinction

Percentages of genera that originate or become extinct during a substage are shown in Figure 17.

Plots are shown for observed ranges in the fossil record (Figure 17 a, c) and observed ranges plus range extensions (Figure 17 b, d) For origination percentages, when only observed ranges are included (Figure 17 a), origination values are high for the Late Cenomanian and Early Turonian.

When range extensions are included (Figure 17 b), there is only heightened origination in the

Late Cenomanian. The median value for the Early Turonian is only slightly higher than those in the Middle Turonian. While the two plots provide conflicting evidence on how high origination was during the Late Cenomanian and Early Turonian, they were not particularly low. Within both plots displaying extinction percentages (Figure 17 c, d), extinction is high in both the Late

Cenomanian and Early Turonian. The high extinctions in the Early Turonian also support the findings of Yacobucci (2017), who observed a large drop in acanthoceratoid genera across the

ET/MT boundary. 44 Using Calibrated Trees 1 and 2, origination percentages are higher in the Lower Turonian than the Upper Cenomanian, while using Calibrated Tree 3, there is a drop in originations across the C/T boundary. When extended ranges are included, there are significant drops in the percentages as the first appearances of taxa are pushed back earlier. Origination values for the

Middle Turonian for calibrated trees 1 and 2 drop by more than half to 38% and 30%, respectively. In Calibrated Tree 3, there is a more modest drop in percent originations, from 63% to 44%, a decrease of 19%. In the Upper Cenomanian, there is only a large decrease in percent origination in Calibrated Tree 1 when range extensions are included, dropping from 86% down to 24% origination. In Calibrated Trees 2 and 3, there is only a small drop in origination percentage, 64% to 59% and 71% to 56%, respectively. This small drop makes it more likely that originations were high in the Upper Cenomanian, although more work is needed to confirm this.

Extinction percentages are more consistent and display a clearer signal. When only including observed ranges, percent extinction is high (>70%) in the Upper Cenomanian and

Lower Turonian across all three trees. While extinction percentages do drop when range extensions are included, it is a smaller drop than origination percentages, never dropping below

50% extinction. The high extinction values in the Upper Cenomanian supports the findings of

Elder (1989) and Harries and Little (1999) while contradicting Monnet (2009), who did not observe an increase in extinction across the C/T boundary within the WIS. The high extinctions in the Lower Turonian also support the findings of Yacobucci (2017), who observed a large drop in acanthoceratoid genera across the LT/MT boundary. 45 a) 35

30

25

20

15

10

5

0 MC LC ET MT LT

b) 30

25

20

15

10

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Figure 16. Standing Diversity. Box and whisker plot showing standing diversity across the three calibrated tree. a) Only taxa included in the phylogenetic analyses. b) Taxa included in phylogenetic analyses plus genera not included in the phylogenetic analysis. Values presented both with and without range extensions (see Appendix E). 46 a)

b)

c) 47

d)

Figure 17. Origination and Extinction. Percentage of genera present in a substage a) originating, b) originating (including range extensions), c) becoming extinct, d) becoming extinct (including range extensions) during that substage. Blue dot represents median value. Error bars indicate maximum and minimum value for that substage based on the three calibrated trees. 48 Westermann Morphospace

Family-Level Patterns

Based on shell morphology, superfamily Acanthoceratoidea covers a wide range of ecologies (Figure 18). With traditional classifications (Figure 18 a), Acanthoceratidae largely plots in the center of the morphospace with the three other families, Coilopoceratidae,

Vascoceratidae, and Collignoniceratidae, each trending toward a single metric, whorl expansion, shell inflation, and umbilical exposure, respectively. Under the new classifications proposed here, Acanthoceratidae still plots in the center and there is still a division between

Collignoniceratidae and Vascoceratidae (Figure 18 b). Vascoceratidae, however, no longer maximizes shell inflation, but instead displays the greatest morphological disparity (largest morphospace occupation), spreading along the axis between spherocones and oxycones.

Acanthoceratidae, while trending towards the middle of the morphospace, has members representing all ecotypes (Figure 19). While still falling near the middle, Collignoniceratidae trends towards the demersal and planktonic zones of the morphospace (Figure 20).

Euomphaloceras, tentatively classified as a collignoniceratid, falls well within the range of morphological variation of Collignoniceratidae, providing mild support for placing it in the group. With the new classifications, Vascoceratidae now displays the greatest morphological disparity, ranging in morphologies that minimize shell inflation, minimize umbilical exposure, and maximize shell inflation (Figure 21 a). When divided into subfamilies, there is little overlap between the two (Figure 21 b). Vascoceratinae tends to display lower shell inflation values while

Coilopoceratinae minimizes umbilical exposure and/or maximizes shell inflation. 49

Figure 18. Westermann Morphospace for All Taxa. a) Westermann morphospace displaying all specimens suitable for measurement with traditional classifications; b) Westermann morphospace displaying all specimens suitable for measurement with proposed reclassifications. Dashed lines display dividing lines between modes of life. Shaded area represents demersal zone. 50

Figure 19. Westermann Morphospace for Acanthoceratidae. Westermann morphospace displaying location of all acanthoceratid specimens (blue) under proposed reclassifications. All other taxa shown in gray. 51

Figure 20. Westermann Morphospace for Collignoniceratidae. Westermann morphospace displaying location of all collignoniceratid specimens (red) under proposed reclassifications. All other taxa shown in gray. 52

Figure 21. Westermann Morphospace for Vascoceratidae. a) Westermann morphospace displaying location of all vascoceratid specimens (purple) under proposed reclassifications. b) Westermann morphospace displaying location of two proposed subfamilies of Vascoceratidae, Vascoceratinae (purple) and Coilopoceratinae (green). All other taxa shown in gray. 53 Ecological Changes Through Time

From the Middle Cenomanian to the Upper Cenomanian, there is little change in morphospace occupation (Figure 22 a, b). During both time periods, most specimens plot towards the center of the space, with several specimens plotting away from the center towards each corner. Across the C/T boundary (Figure 22 b, c), I predicted an overall decrease in ecological disparity due to the loss of taxa. Instead, morphospace occupation increased across the

C/T. Occupation expands towards minimizing whorl expansion, and both minimizing and maximizing umbilical exposure. This increase in occupation is entirely due to the diversification of vascoceratid genera in the Lower Turonian. From the Lower Turonian to the Middle Turonian

(Figure 22 c, d), two shifts occur in morphospace occupation: there is a loss of taxa that minimize whorl expansion and a diversification of taxa that maximize whorl expansion. Again, both shifts are entirely driven by vascoceratid genera. The loss of whorl expansion minimizing taxa is due to the loss of vascoceratine genera, while the expansion of the oxyconic portion of the morphospace is a result of the diversification of coilopoceratine genera. There is no significant shift in morphospace occupation from the Middle Turonian to the Upper Turonian (not shown). 54 55

Figure 22. Westermann Morphospace Occupation Through Time. Westermann morphospace showing location of all taxa from the a) Middle Cenomanian; b) Late Cenomanian; c) Early Turonian; d) Middle Turonian. Color coding reflects proposed reclassifications. 56 DISCUSSION

Phylogenetic Analysis

In the three phylogenetic analyses, four traditionally defined groups were recovered:

Acanthoceratidae, Collignoniceratidae, Vascoceratidae, and Coilopoceratidae, with only a small number of taxa reclassified (note that Coilopoceratidae was recovered, but has tentatively been reclassified as a subfamily of Vascoceratidae). The only family that was not recovered was

Pseudotissotiidae, which is likely due to the small number of pseudotissotiid taxa (see below).

Jackknife and bootstrap analyses show strong support for subfamily Coilopoceratinae and mild support for Hourcqia + Barroisiceras, Collignoniceras + Prionocyclus, and Vascoceratidae as a whole.

Across all analyses, three characters had high consistency indices (ci>0.66): whorl expansion rate (character 4), whorl section shape (character 7), and relative ventral width

(character 8). The high ci for character 4 is likely because only three taxa do not possess the ancestral state, two sharing the same trait. These taxa (Rubroceras and Infabricaticeras) do not group near each other, so this character is likely not phylogenetically informative and should be excluded from future studies. For the second and third analyses, because Infabricaticeras was excluded, character 4 was parsimony uninformative. While characters 7 and 8 do not define any higher level groups, they can be useful for clarifying the topology within families and subfamilies. In all three analyses, three characters consistently had low CI values (ci<0.25): the presence of dimorphism (character 9), the lateral migration of the umbilical tubercle (character

21), and symmetry in the first U saddle (character 37). None of these characters display any phylogenetic signal and should not be included in future studies. 57 Overall, juvenile characters and suture characters appear to be the most useful for grouping taxa together. In this study, only juvenile tubercles were included. Expanding the number of juvenile characters in future studies to include morphological characters (e.g., juvenile expansion rate) will likely provide more accurate results as groups thought to be closely related often appear very similar in early growth stages but different as adults (e.g., Plesiacanthoceras and Metoicoceras). As has been shown in previous studies (Yacobucci, 2012), suture characters are useful in defining higher order groups and should always be included as a major portion of the data matrix.

Pseudotissotiidae Likely the largest problem with the phylogenetic portion of this study is the low number of included pseudotissotiid taxa; only Hourcqia and Choffaticeras were included. While both taxa are well resolved on their respective portions of the tree, they do not plot near each other.

This could be the result of one (or both) not truly belonging to Pseudotissotiidae or because the lack of other pseudotissotiids is preventing them from grouping near one another.

Pseudotissotiidae has been postulated as the precursor to Coilopoceratidae (Cobban and Hook,

1980), and the small number of pseudotissotiid genera could be causing Coilopoceratidae to group together with Vascoceratidae instead (Figures 7, 10, 13). Any future phylogenetic work involving these three groups should include a greater number of pseudotissotiid genera than are included here.

Micromorphs

One early finding was that micromorphic ammonoids should not be included in a parsimony based phylogenetic analysis. Micromorphs often evolve through precocious sexual maturation (i.e., progenesis) (Kennedy and Cobban, 1990), and, as a result, their adult characteristics resemble the juvenile of their ancestors. The inclusion of micromorphs will only 58 confound the results of a phylogenetic analysis. If one is to include micromorphs in an analysis, the analysis should focus solely on juvenile characters.

Standing Diversity

With different estimates of standing diversity almost universally showing a decline across the C/T boundary, it is likely that acanthoceratoid diversity within the WIS dropped because of the C/T extinction event. With the wide range in estimated drops in diversity (16%-44%, Figure

16), it cannot currently be determined how severe the loss in diversity was. A phylogenetic analysis including more acanthoceratoid genera and other superfamilies could help determine how large the drop in diversity actually was. These findings contradict recent studies that have not found a decrease in diversity within the WIS across the C/T boundary (Monnet, 2009). These results instead show a noticeable drop in standing diversity. Yacobucci (2017) also observed significant drops in genus and species level diversity in the WIS across the C/T boundary.

Origination and Extinction

The results for percent origination in a single substage support two opposing hypotheses when range extensions are excluded versus included. The first hypothesis is that there was heightened origination in the Late Cenomanian and Early Turonian, supported by the high origination percentages when only observed ranges are included (Figure 17). The second hypothesis is that there was overall low origination in the Late Cenomanian and Early Turonian, supported by the drop in origination percentages when range extensions are included. The second hypothesis is consistent with Monnet (2009) and Monnet and Bucher (2007), who argued there was no increase in extinction during the C/T extinction event, but instead a lack of origination that led to the loss in diversity. When examining percent extinction, there is heightened generic extinction in both the Upper Cenomanian and Lower Turonian, supporting Elder’s (1989) and 59 Harries and Little’s (1999) findings that there was heightened extinction across the C/T. It is not currently clear whether this is a single extended period of heightened extinction or multiple pulses of increased extinction.

Westermann Morphospace

Assuming the C/T extinction was triggered by rising ocean anoxia, I predicted there would be a loss of planktonic taxa and a shift in morphospace occupation away from the planktonic zone towards more active lifestyles across the C/T boundary. While we do not see a loss of planktonic taxa, there is a shift towards more active lifestyles across the C/T boundary; taxa were expanding into new modes of life that were reflected in shells that minimized umbilical exposure and maximized whorl expansion rate (Figure 22 b, c). Based on available data, there is conflicting evidence on whether rising anoxia was the cause of the extinction, and more work is required.

From the Early Turonian to the Middle Turonian (Figure 22 c, d), there is a noticeable shift toward the nektonic region of the morphospace, with a loss of taxa with large shell inflation values that minimize whorl expansion and an increase in taxa that maximize whorl expansion rate. There is currently no documented environmental change at this time that could account for the loss of inflated vertical migrants in this time interval.

Of the three families included in this study, only Vascoceratidae is not ecologically and morphologically stable through time. The morphological and ecological disparity of both

Collignoniceratidae and Acanthoceratidae is stable; there is little change in morphospace occupation for either group. Vascoceratidae, on the other hand, is the sole driver of both trends discussed above. The evolution and subsequent extinction of subfamily Vascoceratinae is responsible for the expansion into and away from the portion of the morphospace that minimizes 60 whorl expansion rate. The evolution of subfamily Coilopoceratinae resulted in the expansion into and diversification within the regions that minimize umbilical exposure and maximize whorl expansion rate. While not the main driver of diversity patterns (Monnet, 2009), vascoceratid taxa appear to have possessed the unique ability among acanthoceratoid families to evolve novel modes of life and were the sole driver of ecologic changes within sup1erfamily

Acanthoceratoidea within the WIS.

Future Work

1) Pseudotissotiidae, while only a minor family in the WIS, is a more important group in other

regions (Monnet, 2009), especially when considering the origin of Coilopoceratidae. As

presented here, the two pseudotissotiid taxa, Hourcqia and Choffaticeras, do not group near

each other in any phylogenetic hypothesis, which raises questions about the legitimacy of one

or both of their traditional placements into Pseudotissotiidae. Any future phylogenetic

analysis of Acanthoceratoidea should include more taxa from this family to help determine

the origin of Coilopoceratidae and to confirm the phylogenetic placement of Hourcqia and

Choffaticeras.

2) The origin of the families Vascoceratidae and Collignoniceratidae cannot be determined from

any of the phylogenetic hypotheses presented here. It is likely both families originated from

an acanthoceratid genus, and future studies should focus on the taxa within Acanthoceratidae

that are believed to be closely related to the two families.

3) This study focused on the Western Interior Seaway, and therefore one way to expand upon

the results would be to include all acanthoceratoid genera found globally from the Middle

Cenomanian through the Turonian. This expansion would allow for a more complete

understanding of the evolutionary history of the superfamily. This dataset could also be 61 broken down into different regions including the Tethys Ocean and the North and South

Pacific Ocean. Another way to expand would be to include all species for each genus or use

multiple exemplar species per genus. These trees would also expand the data available for

calculating diversity, extinctions and originations, and conducting additional morphological

and ecological studies.

4) While superfamily Acanthoceratoidea is the most diverse ammonoid group during the C-T,

not all other superfamilies display the same patterns of diversity (Yacobucci, 2017).

Repeating this study with each ammonoid superfamily will give a more accurate idea of what

is happening to ammonoids globally in response to changing climate at this time.

5) A crucial step in determining whether increased extinction or decreased speciation led to the

C/T extinction event among ammonoids is calculating extinction and origination rates. By

using the per capita rates proposed by Foote (2000), we would be able to determine which

hypothesis, increased extinction or decreased speciation, if either, is correct. Including more

species or a global dataset would also allow for calculations at a finer stratigraphic resolution

(i.e., ammonoid zone). This better temporal control would show when extinctions and

originations are concentrated (e.g., latest Cenomanian vs. throughout the Late Cenomanian). 62 CONCLUSIONS

In determining whether there is a decrease in standing diversity across the C/T boundary in the WIS, whether decreased speciation or increased extinction in ammonoids led to a drop in diversity in the C/T extinction event, how life modes of acanthoceratoid genera changed in relation to the C/T extinction event, and whether these ecological changes indicate rising anoxia as the cause of the extinction, I found the following:

1) Modest drops in generic diversity are observed across the C/T boundary, reflecting the C/T

extinction event, and across the Early/Middle Turonian boundary.

2) There is an increase in the percentage of genera becoming extinct in the Late Cenomanian

and Early Turonian, but no decrease in origination.

3) From the Late Cenomanian to Early Turonian, there is an increase in morphospace

occupation presumably reflecting an increase in ecological diversity.

4) The expansion of morphospace occupation into more active modes of life and the lack of loss

of planktonic taxa provide conflicting results on whether rising anoxia was the cause of the

C/T extinction among ammonoids.

In addition to answering my primary research questions, I also observed the following:

5) Parsimony-based phylogenetic analyses of acanthoceratoid genera from the Cenomanian-

Turonian Western Interior Seaway of North America recovered three previously erected

groups: Acanthoceratidae, Vascoceratidae, and Collignoniceratidae. Coilopoceratidae was

recovered as a subclade of Vascoceratidae. In total, eight genera are potentially reassignable

to a new family and several cannot be assigned to any family with currently available data. 63 6) Because micromorphic ammonoids evolve through paedomorphosis, such that adults

resemble juveniles of close relatives, they should be excluded from all future phylogenetic

studies unless the study focuses on juvenile characteristics.

7) From the Lower Turonian to the Middle Turonian, there is a loss of taxa with high shell

inflation and low whorl expansion rate.

8) All shifts in morphospace occupation are driven by Vascoceratidae, suggesting that within

Acanthoceratoidea, vascoceratid genera were better at evolving novel modes of life than the

other families. Morphospace occupation within Acanthoceratidae and Collignoniceratidae is

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10.1017/pab.2017.3. 69 APPENDIX A. CHARACTER LIST

Character Description of Character states character 1. Degree of Umbilical 0: 0.24-0.4 involution width divided 1: <0.1 by shell 2: 0.1-0.23 diameter 3: >0.4 2. Whorl shape Whorl width 0: 0.7-1.1 divided by 1: <0.5 whorl height 2: 0.5-0.7 3:1.11-1.5 4: >1.5 3. Shell Whorl width 0: 0.25-0.47 inflation divided by 1: <0.25 (thickness shell diameter 2: >0.47 ratio) 4. Whorl Final whorl 0: 1.25-1.75 expansion height divided 1: <1.25 rate by previous 2: >1.75 whorl height 5. Aperture Distance the 0: <0.2 overlap with outer whorl 1: 0.2-0.32 previous overlaps with 2: >0.32 whorl the previous whorl divided by the aperture height 70 6. Position of Distance from 0: 0.521-0.75 maximum top of venter 1: <0.33 aperture to widest 2: 0.33-0.25 width point of whorl 3: 0.751-0.9 section 4: >0.9 divided by 5: Parallel flanks aperture height

7. Adult whorl Shape of the 0: Square section whorl section shape

USNM 420220 1: Oval (compressed) 71

USNM 411503 2: Tabulate

BEG 20818 3: Round 72

USNM 425234 4: Round or tabulate 5: Oval (depressed)

UT 37105 6: Rounded or oval (depressed) 73

7: rounded triangular

NPL 52428

USNM 328736 8: Lanceolate 74

USNM 275879 9: Fastigate

USNM 329754 10: Square or tabulate 8. Ventral Width of 0: 0.2-0.33 width venter divided 1: <0.1 by shell 2: 0.1-0.2 diameter 3: 0.331-0.45 4: >0.45 8 (continued). 9. Dimorphism Presence/abs 0: Present ence of 1: Absent dimorphism 75 10. Keel Presence/abs 0: Absent ence of a 1: Present ventral keel 11. Rib spacing Distance from 0: 1.71-2.0 the crest of 1: <0.8 two 2: 0.8-1.0 consecutive 3: 1.5-1.7 ribs divided by 4: 0.1-1.49 shell diameter 5: >2.0 6: absent 12. Adult Type of 0: Absent ventral tubercle, if 1: Clavate tubercle any, present 2: Nodate type on the venter 3: Nodate or clavate 4: Bullate or nodate 5: Nodate, clavate, or bullate 13. Adult Presence/abs 0: Absent ventral ence of a 1: Present tubercle ventral presence tubercle 14. Adult Type of 0: Bullate umbilical tubercle, if 1: Absent tubercle any, present 2: Nodate type on umbilical 3: Nodate, clavate, or bullate shoulder 4: Bullate or nodate 15. Adult Presence/abs 0: Present umbilical ence of 1: Absent tubercle tubercles on presence umbilical shoulder 16. Adult inner Type of 0: Horns ventrolatera tubercle, if 1: Bullate l tubercle any, present 2: Clavate type on dorsal side 3: Nodate of 4: Nodate or clavate ventrolateral 5: Clavate or bullate shoulder 6: Absent or bullate 7: Absent or nodate 8: Spines or clavate 9: absent 10: Spines 11: Nodate or merged with OVL 76 17. Adult inner Presence/abs 0: Present ventrolatera ence of 1: Absent l tubercle tubercle of presence dorsal side of ventrolateral shoulder 18. Adult outer Type of 0: Bullate ventrolatera tubercle, if 1: Absent l tubercle any, present 2: Nodate type on the ventral 3: Clavate side of the 4: Nodate or clavate ventrolateral 5: Nodate, Clavate, or bullate shoulder 6: Nodate or bullate 7: Clavate or bullate 8: Clavate or merged with IVL 9: Absent, nodate, or clavate 19. Adult outer Presence/abs 0: Present ventrolatera ence of 1: Absent l tubercle tubercle on presence ventral side of ventrolateral shoulder 20. Adult most Location of 0: IVL prominent the largest 1: OVL tubercle tubercles 2: Umbilical or OVL location 3: IVL, umbilical, or OVL 4: Umbilical 5: Absent 6: OVL or IVL 7: Lateral 8: Ventral 21. Ventral Gradual 0: Present migration of migration of 1: Absent umbilical the umbilical tubercle tubercle towards the venter through ontogeny 22. Juvenile Type of 0: Clavate ventral tubercle, if 1: Absent tubercle any, present 2: Nodate type on the venter 3: Nodate or clavate 77 23. Juvenile Presence/abs 0: Present ventral ence of a 1: Absent tubercle ventral present tubercle 24. Juvenile Type of 0: Bullate umbilical tubercle, if 1: Absent tubercle any, present 2: Nodate type on umbilical 3: Nodate or bullate shoulder 4: Absent or bullate 25. Juvenile Presence/abs 0: Present umbilical ence of 1: Absent tubercle tubercles on 2: Absent or present presence umbilical shoulder 26. Juvenile Type of 0: Nodate inner tubercle, if 1: Absent ventrolatera any, present 2: Clavate l tubercle on dorsal side 3: Bullate type of 4: Nodate or clavate ventrolateral 5: Nodate or bullate 26 (continued). shoulder 6: Spines

27. Juvenile Presence/abs 0: Present inner ence of 1: Absent ventrolatera tubercle of l tubercle dorsal side of presence ventrolateral shoulder 28. Juvenile Type of 0: Clavate outer tubercle, if 1: Nodate ventrolatera any, present 2: Absent l tubercle on the ventral 3: Nodate or clavate type side of the 4: Absent or bullate ventrolateral 5: Bullate shoulder 29. Juvenile Presence/abs 0: Present outer ence of 1: Absent ventrolatera tubercle on 2: Absent or present l tubercle ventral side of presence ventrolateral shoulder 30. Juvenile Type of 0: IVL most tubercle, if 1: Ventral 78 prominent any, present 2: OVL tubercle on umbilical 3: IVL or OVL shoulder 4: Absent 5: Umbilical 6: IVL or umbilical 7: OVL or Umbilical 31. Suture Qualitative 0: Moderate complexity description of how many crenellations are present in the adult suture Mammites 1: Simple

Eucalycoceras 2: Complex

Calycoceras 32. Division of How many 0: Bifid external major saddle crenulations are present on the external saddle 79 Rubroceras 1: Trifid

Paraconlinoceras 2: Unifid

\ Vascoceras 3: Polyfid

Eucalycoceras 4: Bifid or trifid 33. Division of How many 0: Bifid lateral lobe major crenulations are present on the lateral lobe

Acanthoceras 80 1: Unifid

Neocardioceras 2: Trifid

Romaniceras 3: Polyfid

Hoplitoides 34. Division of How many 0: Bifid lateral major saddle crenulations present on the lateral saddle 81

Eucalycoceras 1: Unifid

Vascoceras 2: Trifid

Hourcqia 3: Polyfid 82

35. Division of How many 0: Unifid first U major saddle crenulations present on the first U saddle

Hourcqia 1: Bifid

Prionocyclus 2: Trifid 83

Coilopoceras 36. Symmetry in Presence/abs 0: Present or absent lateral ence of 1: Present saddle symmetry in the lateral saddle

Romaniceras 2: Absent

Pseudocalycoceras 37. Symmetry in Presence/ 0: Absent first U absence of saddle symmetry in the first U saddle 84

Neocardioceras 1: Present

Pseudocalycoceras 38. Symmetry in Presence/ 0: Present lateral lobe absence of symmetry in the lateral lobe

Morrowites 1: Absent 85

Hourcqia 39. Lateral General shape 0: Square saddle of the lateral shape saddle

Prionocyclus 1: Rounded

Neocardioceras 2: Elongated

Morrowites 3: Rounded or square 86 40. First U General shape 0: Square saddle of the first U shape saddle

Prionocyclus 1: Rounded

Rubroceras 2: Elongated

Eucalycoceras 3: Rounded or square 41. External External 0: <0.27 saddle saddle height, 1: 0.27-0.39 height measured 2: 0.4-0.44 from the 3: ≥0.45 deepest point on an adjacent lobe 87 divided by lateral saddle height, measured from the deepest point on an adjacent lobe 42. First U First U saddle 0: 0.8-1.09 saddle height, 1: 0.5-0.79 height measured 2: 1.1-1.29 from the 3: ≥1.3 deepest point on an adjacent lobe divided by lateral saddle height, measured from the deepest point on an adjacent lobe 43. External Which lobe, 0: E lobe lobe depth the E lobe or L vs. lateral lobe, extends lobe depth further apically

Paraconlinoceras 1: Equal

Romaniceras 88 2: E lobe or equal 3: L lobe

Metoicoceras 4: L lobe or equal 44. Lateral Location of 0: Central saddle deepest major deepest crenulation on element the lateral saddle

Romaniceras 1: Dorsal

Infabricaticeras 2: Ventral 3: Absent (no major crenulation on lateral saddle)

Pseudaspidoceras 89 4: Central and ventral equally deep

Hourcqia 45. First U Location of 0: Absent saddle deepest the largest element major crenulation on the first U saddle

Eucalycoceras 1: Central

Barroisiceras 2: Ventral 90

Microdiphasoceras 46. Skew of Direction or 0: Absent lateral saddle absence of the direction the top of the L saddle is sloping

Romaniceras 1: Dorsal

Romaniceras 2: Ventral 91 Eucalycoceras 3: Absent or dorsal 4: Absent, dorsal, or ventral 47. Presence/abs 0: Absent Constriction in ence of a lateral saddle constriction on the lateral saddle

Romaniceras 1: Present

Hoplitoides

Hourcqia 48. External External 0: 1.0-2.0 saddle height saddle height, 1: <1.0 measured 2: >2.0 from the deepest point 92 on an adjacent lobe, divided by width 49. Lateral Lateral saddle 0: <1.3 saddle height height, 1: 1.3-1.6 measured 2: >1.6 from the deepest point on an adjacent lobe, divided by width 50. First U Location of 0: Equal saddle position the most 1: Posteriorly relative to anterior 2: Anteriorly lateral saddle portion of the 3: Equal or posteriorly position first U saddle 4: Posteriorly, anteriorly, or equal relative to the L saddle 93 APPENDIX B. DATA MATRIX FOR PHYLOGENTIC ANALYSIS

Numbers indicate character state. Letters A and B indicate character states 10 and 11. The symbol ? indicates missing data.

Acanthoceras 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 Cunningtoniceras 00000 00000 50000 00000 03030 60300 22000 2?002 20000 11000 Conlinoceras 00000 03200 40000 91511 00000 00002 21201 11012 30001 10200 Paraconlinoceras 03000 2??00 54100 91511 02000 40302 11001 20101 10001 ?0100 Dunveganoceras 00000 03010 40011 10005 01100 00003 10100 21000 30100 10000 Tarrantoceras 00000 03000 11100 91312 10000 00002 04000 20033 30000 10000 Plesiacanthoceras 00000 04010 50000 40310 01100 00002 2?100 1?002 21300 10200 Neocardioceras 00000 0?010 11100 10114 12011 30101 10100 20011 3?020 10001 Watinoceras 00000 3??10 20000 40313 11100 20002 1?1?0 ?0002 ????2 ?0??2 Calycoceras 03201 03?00 20000 91004 11100 01215 23200 10003 50200 00000 Eucalycoceras 00000 ???10 11100 9121? ?0020 10002 13100 21002 30000 20001 Pseudocalycoceras 00000 0??00 21130 20311 10000 10002 11000 20002 30010 40001 Nigericeras 00000 01?10 30000 91004 10030 50306 0101? 1??2? ?0?0? 0000? Euomphaloceras 03200 03000 ?5120 A0610 02000 30500 01010 11010 30011 00000 Morrowites 03201 15010 30000 20000 11120 10106 20010 21022 ??010 01010 Kamerunoceras ???0? 06?10 41100 20210 01100 40302 0?20? 0?00? 20?01 30?00 Pseudaspidoceras 00000 30010 30000 20??0 11100 20000 01010 01122 20330 00210 Romaniceras 00000 50000 41100 00216 10000 10002 22201 10000 32101 00001 Metoicoceras 22001 01200 20000 50716 11142 20002 02100 20002 32300 30001 Spathites 20202 02000 ?0011 ?1?06 11130 40007 1410? 11010 20001 00203 Mammites 00001 1A000 00000 00001 ?1130 10005 0?100 11001 30100 10000 Vascoceras 20001 03?10 40000 91004 11101 01215 12100 21122 20100 00200 Neoptychites 10202 38000 60011 91005 11111 01214 11201 21012 30301 00?10 Fagesia 04201 ?5300 40020 91004 11121 01215 00010 11022 30130 00010 Infabricaticeras 23211 ???10 30000 30004 11100 01215 1?000 21003 ???11 10??1 Rubroceras 04010 ?7?00 60000 10000 12000 50??0 10010 21011 30010 10200 Choffaticeras 11102 09110 60011 91005 11111 20210 1?000 2010? ?3300 00?04 Hourcqia 20005 0A011 4?100 30000 10000 ????? 20020 2112? 40040 01?21 Cibolaites 00001 0A011 41100 20004 10000 01005 10100 2000? 31?00 1010? Collignoniceras 30000 03001 31100 B0816 00000 20001 20200 1100? 31300 00202 Barroisiceras 02000 09??1 41100 30000 10020 20211 0?001 2010? 41?01 00?13 Hoplitoides 11002 39100 60011 91005 11111 01211 2?341 2?12? 303?1 01?20 Coilopoceras 21022 09110 60011 91005 11142 01424 23332 2112? 313?1 01100 Prionocyclus 00000 2B001 41040 80410 00000 40003 20201 2100? 31400 00?00 Sumitomoceras 00000 51?00 10100 91314 11100 10100 11?01 1100? 00101 10000 94 APPENDIX C. OTHER PHYLOGENETIC ANALYSES

Majority rule consensus tree of 44 MPTs with a tree length of 344 for a phylogenetic analysis with all taxa included in Consensus Tree 2 (Figure 10) with Morrowites removed. CI=0.4535. RI=0.4849. RC=0.2199. 95

Majority rule consensus tree of 128 MPTs with a tree length of 348 for a phylogenetic analysis with all taxa included in Consensus Tree 2 (Figure 10) with Nigericeras removed. CI=0.4511. RI=0.4810. RC=0.2170. 96

Majority rule consensus tree of 17 MPTs with a tree length of 319 for a phylogenetic analysis with all taxa included in Consensus Tree 2 (Figure 10) with Morrowites, Pseudaspidoceras, and Nigericeras removed. CI=0.4859. RI=0.5060. RC=0.2459. 97 APPENDIX D. RAW MEASUREMENTS

See supplemental material 98 APPENDIX E. STANDING DIVERSITY RAW VALUES

List of standing generic diversity from the Middle Cenomanian through the Upper Turonian. For each calibrated tree, standing diversity is given when only including genera present on the tree and separately for taxa on the tree plus all genera not included in the phylogenetic analysis but known from that time interval (removed taxa). The first number indicates the raw taxon count plus range extensions. Numbers in parentheses indicate raw taxon counts not including range extensions. MC, Middle Cenomanian; LC, Late Cenomanian; ET, Early Turonian; MT, Middle Turonian; LT, Late Turonian.

Substage Calibrated Calibrated Calibrated Calibrated Calibrated Calibrated tree 1 tree 1 + tree 2 2 + tree 3 tree 3 + removed removed removed taxa taxa taxa LT 8 9 6 9 6 9 MT 8 12 5 12 5 12 ET 16 (15) 22 (21) 10 (9) 22 (21) 9 (8) 21 (20) LC 21 (14) 33 (26) 17 (13) 29 (25) 16 (14) 28 (26) MC 20 (8) 24 (12) 13 (8) 17 (12) 11 (8) 15 (12) 99 APPENDIX F. ORIGINATION AND EXTINCTION PERCENTAGES

Percentage of taxa that are present in a substage that either originate or become extinct during that substage. Percentages calculated with and without inferred range extensions are included. MC, Middle Cenomanian; LC, Late Cenomanian; ET, Early Turonian; MT, Middle Turonian; LT, Late Turonian.

Substage Origination % Origination % Extinction % Extinction % w/ range w/ range extensions extensions Calibrated Tree 1 LT 25 25 - - MT 38 25 25 25 ET 80 38 67 63 LC 86 24 79 52 MC - - 50 20 Calibrated Tree 2 LT 33 33 - - MT 60 40 20 40 ET 67 60 78 70 LC 64 59 79 65 MC - - 50 31 Calibrated Tree 3 LT 33 33 - - MT 60 40 20 20 ET 63 44 75 67 LC 71 56 79 69 MC - - 50 36 100 APPENDIX G. NORMALIZED WESTERMANN MORPHOSPACE VALUES

Specimen Genus w U Th USNM 239768 Acanthoceras amphibolum 0.61 0.44 0.53 USNM 252726 Acanthoceras amphibolum 0.36 0.41 0.61 USNM 239769 Acanthoceras amphibolum 0.56 0.49 0.48 USNM 420231 Acanthoceras amphibolum 0.66 0.65 0.52 USNM 239767 Acanthoceras amphibolum 0.59 0.50 0.74 NMNH 420218 Acanthoceras amphibolum 0.67 0.42 0.54 NMNH 420226 Acanthoceras amphibolum 0.80 0.32 0.79 USNM 423718 Alzadites westonensis 0.67 0.54 1.05 USNM 423720 Alzadites westonensis 0.61 0.60 1.29 USNM 423714 Alzadites westonensis 0.58 0.61 1.38 USNM 423723 Alzadites westonensis 0.61 0.59 1.16 USNM 73753 Barroisiceras dentatocarinatum 0.36 0.57 0.25 USNM 423770 Buccinammonites minimus 0.77 0.31 0.80 USNM 425258 Burroceras transitorium 0.92 0.71 0.57 USNM 425264 Burroceras transitorium 0.58 0.60 0.82 USNM 425260 Burroceras transitorium 0.61 0.63 0.62 USNM 425265 Burroceras transitorium 0.69 0.62 0.64 USNM 166374 Calycoceras naviculare 0.56 0.57 0.77 USNM 166930 Calycoceras naviculare 0.04 0.62 0.57 USNM 166372 Calycoceras naviculare 0.68 0.57 0.59 USNM 164050 Choffaticeras pavillieri 0.83 0.17 0.14 USNM 164052 Choffaticeras pavillieri 0.40 0.11 0.04 USNM 498204 Cibolaites molenaari 0.54 0.44 0.48 USNM 329754 Cibolaites molenaari 0.48 0.52 0.53 USNM 328766 Cibolaites molenaari 0.60 0.53 0.33 USNM 498209 Cibolaites molenaari 0.80 0.47 0.53 USNM 278120 Coilopoceras springeri 0.88 0.16 0.27 NPL 1850 Coilopoceras springeri 2.11 0.12 0.21 USNM 275912 Coilopoceras springeri 0.56 0.15 0.23 NPL 579 Coilopoceras springeri 0.59 0.36 0.34 NPL 569 Coilopoceras springeri 1.36 0.48 0.31 USNM 275913 Coilopoceras springeri 0.79 0.10 0.21 NPL 576 Coilopoceras springeri 1.52 0.33 0.37 USNM 275914 Coilopoceras springeri 0.89 0.10 0.18 NPL 570 Coilopoceras springeri 1.50 0.31 0.38 NPL 574 Coilopoceras springeri 0.92 0.26 0.26 NPL 573 Coilopoceras springeri 1.63 0.50 0.36 NPL 1852 Coilopoceras springeri 0.48 0.12 0.25 NPL 582 Coilopoceras springeri 0.18 0.24 USNM 275908 Coilopoceras springeri 0.78 0.08 0.22 USNM 275912 Coilopoceras springeri 0.41 0.13 0.26 WSA 2227 Collignoniceras woolgari 0.68 0.79 0.30 101 USNM 498232 Collignoniceras woolgari 0.43 0.72 0.41 USNM 498236 Collignoniceras woolgari 0.29 0.75 0.24 USNM 498237 Collignoniceras woolgari 0.71 0.76 0.27 USNM 258940 Collignoniceras woolgari 0.61 0.84 0.26 USNM 498224 Collignoniceras woolgari 0.53 0.81 0.17 USNM 498240 Collignoniceras woolgari 0.62 0.61 0.30 USNM 252790 Collignoniceras woolgari 0.81 0.74 0.34 USNM 252804 Collignoniceras woolgari 0.46 0.89 0.35 USNM 498302 Collignoniceratities collisniger 0.24 0.56 0.26 USNM 498296 Collignoniceratities collisniger 0.46 0.52 0.39 USNM 498300 Collignoniceratities collisniger 0.41 0.57 0.39 USNM 498298 Collignoniceratities collisniger 0.40 0.62 0.39 USNM 498295 Collignoniceratities collisniger 0.30 0.51 0.36 USNM 420238 Conlinoceras tarrantense 0.59 0.37 0.70 NPL 36303 Conlinoceras tarrantense 0.64 0.48 0.58 USNM 420239 Conlinoceras tarrantense 0.81 0.43 0.71 USNM 420251 Conlinoceras tarrantense 0.64 0.52 0.51 Wallace col. 4 Conlinoceras tarrantense 0.73 0.43 0.49 NPL 69339 Conlinoceras tarrantense 0.62 0.46 0.51 NPL 36403 Conlinoceras tarrantense 0.61 0.60 0.42 USNM 420236 Conlinoceras tarrantense 0.96 0.36 0.76 USNM 420250 Conlinoceras tarrantense 0.47 0.64 0.48 USNM 420242 Conlinoceras tarrantense 0.68 0.43 0.54 USNM 420232 Conlinoceras tarrantense 0.35 0.33 0.88 Wallace col. 2 Conlinoceras tarrantense 0.69 0.49 0.56 USNM 420241 Conlinoceras tarrantense 0.91 0.45 0.63 Wallace col. 5 Conlinoceras tarrantense 0.70 0.34 0.56 Wallace col. 1 Conlinoceras tarrantense 0.70 0.47 0.59 NPL 36302 Conlinoceras tarrantense 0.73 0.43 0.55 USNM 420234 Conlinoceras tarrantense 0.87 0.41 0.72 USNM 420254 Conlinoceras tarrantense 0.70 0.57 0.50 USNM 388128 Cunningtoniceras amphibolum 0.61 0.37 0.68 USNM 388127 Cunningtoniceras amphibolum 0.67 0.41 0.69 USNM 108328 Dunveganoceras albertense 0.47 0.61 0.51 USNM 108328 Dunveganoceras albertense 0.29 0.79 0.39 USNM Dunveganoceras albertense 108327b 0.23 0.80 0.20 USNM 400782 Eucalycoceras templetonense 0.36 0.43 0.21 USNM 400785 Eucalycoceras templetonense 0.35 0.39 0.26 USNM 425232 Euomphaloceras septemseriatum 0.33 0.37 0.30 USNM 425227 Euomphaloceras septemseriatum 0.27 0.38 0.35 USNM 425229 Euomphaloceras septemseriatum 0.24 0.36 0.40 USNM 425234 Euomphaloceras septemseriatum 0.25 0.44 0.32 USNM 425228 Euomphaloceras septemseriatum 0.41 0.24 0.35 USNM 425382 Fagesia catinus 0.24 0.30 0.46 102 USNM 425386 Fagesia catinus 0.25 0.30 0.45 USNM 425385 Fagesia catinus 0.16 0.30 0.54 USNM 425387 Fagesia catinus 0.08 0.34 0.58 USNM 425383 Fagesia catinus 0.15 0.31 0.54 UT 37115 Fagesia catinus 0.32 0.27 0.41 USNM 420146 Hoplitoides sandovalensis 0.70 0.10 0.20 USNM 275883 Hoplitoides sandovalensis 0.75 0.05 0.20 USNM 275878 Hoplitoides sandovalensis 0.67 0.12 0.21 USNM 275881 Hoplitoides sandovalensis 0.72 0.07 0.21 USNM 252969 Hoplitoides sandovalensis 0.61 0.12 0.26 USNM 414518 Hourcquia mirabilis 0.34 0.24 0.42 USNM 425401 Infabricaticeras lunaense 0.27 0.55 USNM 423705 Kastanoceras spiniger 0.25 0.30 0.45 USNM 423699 Kastanoceras spiniger 0.34 0.35 0.31 USNM 423701 Kastanoceras spiniger 0.18 0.36 0.46 USNM 423703 Kastanoceras spiniger 0.31 0.27 0.41 USNM 423702 Kastanoceras spiniger 0.24 0.33 0.43 USNM 423700 Kastanoceras spiniger 0.11 0.25 0.64 USNM 328719 Mammites nodosoides 0.34 0.28 0.38 USNM 328716 Mammites nodosoides 0.39 0.31 0.30 WSA 188 Mammites nodosoides 0.35 0.40 0.25 NPL 36425 Metoicoceras geslinianum 0.60 0.14 0.25 USNM 411500 Metoicoceras geslinianum 0.39 0.37 0.24 NPL 36402 Metoicoceras geslinianum 0.48 0.30 0.22 USNM 425301 Metoicoceras geslinianum 0.58 0.12 0.30 USNM 411507 Metoicoceras geslinianum 0.30 0.47 0.23 USNM 411501 Metoicoceras geslinianum 0.46 0.31 0.23 USNM 427950 Metoicoceras geslinianum 0.63 0.15 0.21 USNM 425303 Metoicoceras geslinianum 0.53 0.14 0.33 USNM 411504 Metoicoceras geslinianum 0.44 0.31 0.25 USNM 411503 Metoicoceras geslinianum 0.38 0.38 0.24 USNM 411506 Metoicoceras geslinianum 0.40 0.34 0.26 USNM 425302 Metoicoceras geslinianum 0.47 0.21 0.33 USNM 425405 Microdiphasoceras novimexicanum 0.36 0.38 0.26 USNM 423734 Microsulcatoceras puzosiiforme 0.32 0.41 0.27 USNM 328722 Morrowites subdepressus 0.35 0.24 0.40 USNM 328728 Morrowites subdepressus 0.27 0.27 0.47 USNM 328727 Morrowites subdepressus 0.28 0.24 0.48 USNM 328724 Morrowites subdepressus 0.32 0.23 0.45 USNM 328725 Morrowites subdepressus 0.34 0.28 0.38 USNM 411509 Nannometoicoceras acceleratum 0.07 USNM 411511 Nannometoicoceras acceleratum 0.09 0.02 0.90 USNM 411508 Nannometoicoceras acceleratum 0.09 0.03 0.88 USNM 400818 Neocardioceras juddii 0.20 0.53 0.26 103 USNM 400819 Neocardioceras juddii 0.28 0.46 0.26 USNM 400827 Neocardioceras juddii 0.40 0.34 0.26 USNM356889 Neocardioceras juddii 0.28 0.45 0.28 USNM 400824 Neocardioceras juddii 0.37 0.46 0.18 USNM 400822 Neocardioceras juddii 0.39 0.42 0.19 USNM 425207 Neocardioceras juddii 0.38 0.41 0.21 USNM 328743 Neoptychites cephalotus 0.48 0.10 0.42 USNM 328747 Neoptychites cephalotus 0.41 0.09 0.49 USNM 328736 Neoptychites cephalotus 0.47 0.09 0.44 USNM 328738 Neoptychites cephalotus 0.56 0.09 0.35 USNM 328746 Neoptychites cephalotus 0.33 0.09 0.59 NPL 52428 Neoptychites cephalotus 0.34 0.16 0.50 BEG 34778 Neoptychites cephalotus 0.31 0.08 0.61 USNM 328744 Neoptychites cephalotus 0.48 0.08 0.44 USNM 328740 Neoptychites cephalotus 0.35 0.10 0.55 USNM 328745 Neoptychites cephalotus 0.35 0.09 0.56 BEG 34777 Neoptychites xetriformis 0.37 0.12 0.51 USNM 166396 Nigericeras scotti 0.42 0.36 0.22 USNM 166399 Nigericeras scotti 0.35 0.39 0.25 USNM 420256 Paraconlinoceras leonense 0.17 0.50 0.34 USNM 252732 Plesiacanthoceras wyomingense 0.49 0.31 0.20 USNM 388159 Plesiacanthoceras wyomingense 0.50 0.17 0.34 USNM 388162 Plesiacanthoceras wyomingense 0.38 0.18 0.43 USNM 388158 Plesiacanthoceras wyomingense 0.52 0.13 0.35 USNM 220381 Plesiacanthoceras wyomingense 0.38 0.34 0.27 USNM 420292 Plesiacanthoceratoides vetula 0.34 0.16 0.50 USNM 420288 Plesiacanthoceratoides vetula 0.35 0.16 0.48 USNM 420287 Plesiacanthoceratoides vetula 0.43 0.16 0.40 USNM 420291 Plesiacanthoceratoides vetula 0.25 0.19 0.56 USNM 420144 Prionocyclites mite 0.35 0.46 0.19 NPL 607 Prionocyclites mite 0.61 0.23 0.16 BEG 2612.A Prionocyclus hyatti 0.21 0.48 0.32 USNM 420104 Prionocyclus hyatti 0.38 0.40 0.22 USNM 498327 Prionocyclus hyatti 0.41 0.44 0.15 NPL 36379 Prionocyclus hyatti 0.55 0.33 0.12 NPL 551 Prionocyclus hyatti 0.45 0.35 0.20 NPL 547 Prionocyclus hyatti 0.24 0.52 0.24 USNM 420127 Prionocyclus hyatti 0.39 0.43 0.18 USNM 388181 Protacanthoceras hosei 0.20 0.29 0.51 USNM 388171 Protacanthoceras hosei 0.42 0.22 0.36 USNM 388170 Protacanthoceras hosei 0.45 0.26 0.29 USNM 388178 Protacanthoceras hosei 0.45 0.24 0.31 USNM 388185 Protacanthoceras hosei 0.34 0.13 0.53 USNM 388183 Protacanthoceras hosei 0.15 0.23 0.63 USNM 388182 Protacanthoceras hosei 0.36 0.22 0.42 104 USNM 400791 Pseudocalycoceras angolaense 0.34 0.40 0.26 USNM 400789 Pseudocalycoceras angolaense 0.25 0.38 0.37 USNM 400794 Pseudocalycoceras angolaense 0.45 0.28 0.28 USNM 425204 Pseudocalycoceras angolaense 0.21 0.48 0.30 USNM 400797 Pseudocalycoceras angolaense 0.36 0.38 0.27 USNM 400790 Pseudocalycoceras angolaense 0.34 0.35 0.31 USNM 411608 Romaniceras mexicanum 0.34 0.34 0.32 USNM 411604 Romaniceras mexicanum 0.38 0.31 0.31 USNM 411601 Romaniceras mexicanum 0.35 0.36 0.29 USNM 411602 Romaniceras mexicanum 0.50 0.25 0.25 USNM 411607 Romaniceras mexicanum 0.38 0.30 0.32 USNM 417316 Romaniceras mexicanum 0.44 0.27 0.29 USNM 411600 Romaniceras mexicanum 0.46 0.33 0.21 USNM 411604 Romaniceras mexicanum 0.46 0.28 0.26 BEG Romaniceras mexicanum 17255.8/.11 0.41 0.30 0.29 USNM 425417 Rubroceras alatum 0.17 0.47 0.36 BEG 20818 Spathites coahuilensis 0.43 0.14 0.43 BEG 17255.33 Spathites coahuilensis 0.46 0.16 0.37 BEG 17256.46 Spathites coahuilensis 0.50 0.10 0.40 BEG 20838 Spathites coahuilensis 0.54 0.15 0.31 BEG 20806 Spathites coahuilensis 0.34 0.17 0.49 BEG 20810 Spathites coahuilensis 0.41 0.12 0.47 BEG 20814 Spathites coahuilensis 0.34 0.21 0.45 BEG 20823 Spathites coahuilensis 0.49 0.14 0.38 USNM 400809 Sumitomoceras conlini 0.32 0.46 0.22 USNM 400808 Sumitomoceras conlini 0.37 0.40 0.23 USNM 400804 Sumitomoceras conlini 0.41 0.26 0.32 USNM 400761 Tarrantoceras sellardsi 0.24 0.53 0.23 USNM 400765 Tarrantoceras sellardsi 0.44 0.35 0.21 USNM 400766 Tarrantoceras sellardsi 0.34 0.35 0.31 USNM 400759 Tarrantoceras sellardsi 0.42 0.37 0.21 USNM 400763 Tarrantoceras sellardsi 0.27 0.39 0.34 USNM 400767 Tarrantoceras sellardsi 0.35 0.31 0.34 USNM 164034 Vascoceras birchbyi 0.50 0.23 0.27 USNM 164027 Vascoceras birchbyi 0.28 0.33 0.39 USNM 425368 Vascoceras birchbyi 0.17 0.31 0.52 USNM 164042 Vascoceras birchbyi 0.31 0.17 0.52 USNM 164022 Vascoceras birchbyi 0.18 0.52 0.31 USNM 163998 Watinoceras coloradoense 0.24 0.30 0.46 105

APPENDIX H. TUBERCLE AND SUTURE TERMS 106

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