Resurrecting the Duck-Billed "Giant Cow": Ahshislesaurus wimani and the Diversity of the San Juan Basin Hadrosaurids

Abstract

The early 21st century has witnessed a renaissance in vertebrate paleontology, characterized not only by new excavations but by the rigorous re-examination of legacy collections. This report provides an exhaustive analysis of Ahshislesaurus wimani, a massive saurolophine hadrosaurid from the Late Cretaceous (Campanian) of New Mexico. Originally discovered in 1916 by the pioneering geologist John B. Reeside Jr. during a United States Geological Survey expedition, the holotype specimen (USNM VP-8629) remained taxonomically obscured for nearly a century, conflated with the wastebasket taxon Kritosaurus navajovius. Its formal description in late 2025/early 2026 by an international team led by Sebastian Dalman marks a significant pivot in our understanding of southern Laramidian biogeography. This document explores the historical odyssey of the specimen, the detailed anatomical diagnostics that distinguish it as a new genus, the phylogenetic implications for the tribe Kritosaurini, and the paleoecological context of the Hunter Wash Member of the Kirtland Formation. Through this lens, we examine the broader themes of dinosaur provincialism, the utility of museum archives, and the evolutionary dynamics of the "duck-billed" giants that dominated the Cretaceous landscape.

1. Introduction: The Giant Hadrosaurid in the Drawer

In the popular imagination, the discovery of a new dinosaur is often framed as a cinematic moment: a brush clearing sand from bone in a remote, sun-baked desert, followed by immediate revelation. The reality of paleontological progress is frequently more quiet, occurring in the dusty silence of museum collections where specimens, excavated decades prior, await the scrutiny of new technologies and updated theoretical frameworks. Such is the narrative of Ahshislesaurus wimani, a dinosaur that waited one hundred and nine years to receive its name.

Dubbed the "giant cow of the Cretaceous" by science communicators following its recent unveiling, Ahshislesaurus was a Titan of its time.¹ With a body length estimated between 10 and 12 meters and a mass exceeding 8 metric tons, it rivaled the largest hadrosaurs of the northern plains.² Yet, for the majority of the 20th century, this colossal herbivore was essentially invisible to science, hidden in plain sight under the label of a different dinosaur.

The re-identification of Ahshislesaurus is not merely a matter of taxonomic bookkeeping. It represents a critical piece of evidence in a long-standing debate regarding the biogeography of Late Cretaceous North America. During the Campanian stage, the continent was bisected by the Western Interior Seaway, creating the landmass of Laramidia to the west. While northern Laramidia (modern-day Alberta and Montana) has yielded a rich and well-understood fossil record, the southern fauna (New Mexico, Utah, Texas) has historically been more enigmatic.³

The presence of Ahshislesaurus in the Hunter Wash Member of the Kirtland Formation—stratigraphically separated from its supposed relative Kritosaurus—supports the hypothesis that dinosaur populations in the south were highly endemic and rapidly evolving. This report synthesizes the findings of the 2025/2026 description published in the Bulletin of the New Mexico Museum of Natural History and Science with historical archival data and broader ecological studies.⁴ It aims to provide a definitive account of the animal's history, anatomy, and world.

2. The Historical Canvas: Discovery and Obscurity

2.1 The 1916 USGS San Juan Basin Expedition

To understand the discovery of Ahshislesaurus, one must look back to the early 20th century, a "heroic age" of American geological surveying. In the summer of 1916, the United States Geological Survey (USGS) dispatched a field party to the San Juan Basin of northwestern New Mexico. The primary objective was not the hunt for dinosaurs, but the pragmatic mapping of coal resources and stratigraphy in a region known for its complex geology.⁶

The expedition was part of a multi-year effort to understand the Cretaceous-Tertiary boundary in the American Southwest. Among the team members was John B. Reeside Jr., a young geologist who would go on to become one of the most influential stratigraphers of his generation. Reeside's work was characterized by meticulous attention to detail; the team utilized plane tables and alidades—optical instruments used for determining distances and elevations—to create precise maps of the formation boundaries.⁶

The logistical reality of the 1916 expedition was arduous. The team operated on horseback, navigating the treacherous badlands of the basin where water was scarce and the terrain unforgiving.⁸ They established tent camps, moving by wagon as they traced the outcrops of the Fruitland and Kirtland formations. It was in this rugged context, specifically within the erosion-carved landscape of the Ah-shi-sle-pah Wash, that Reeside encountered the fossilized remains of a massive animal.⁴

The specimen, later cataloged as USNM VP-8629, consisted of a partial skull, a series of articulated cervical vertebrae, and various other skeletal elements.³ Recognizing the potential significance of the find, Reeside collected the material. It was crated and shipped east to the United States National Museum (now the National Museum of Natural History, Smithsonian Institution) in Washington, D.C., where it would join the growing collections of the nation's premier scientific repository.⁴

2.2 The "Kritosaurus" Wastebasket

In 1935, the specimen came under the gaze of Charles W. Gilmore, a legendary vertebrate paleontologist at the Smithsonian. Gilmore was tasked with making sense of the reptilian fossils collected by the USGS parties. By the mid-1930s, the taxonomy of hadrosaurs (duck-billed dinosaurs) was in a state of flux. The genus Kritosaurus had been established in 1910 by Barnum Brown, based on a skull found in the same general region of New Mexico.⁹

Gilmore, examining Reeside's 1916 find, noted the general similarities between it and Brown's Kritosaurus. Both were large, flat-headed hadrosaurs (lacking the flamboyant hollow crests of the lambeosaurines) and both hailed from the Kirtland Formation. At the time, the concept of fine-scale stratigraphic resolution was less developed, and the subtle anatomical differences between specimens were often attributed to individual variation or sexual dimorphism rather than specific distinctness.³

Consequently, Gilmore referred USNM VP-8629 to Kritosaurus navajovius.⁴ This decision had a lasting impact. For the next ninety years, Kritosaurus became a "wastebasket taxon"—a default category for almost any non-crested hadrosaur found in the southern United States. Specimens from Texas, Mexico, and various horizons in New Mexico were all lumped into this single genus, effectively smoothing over the biological diversity of the region.³

2.3 The Long Sleep and the Awakening

Throughout the 20th century, USNM VP-8629 remained in the collections, largely unquestioned. However, the turn of the millennium brought a paradigm shift in dinosaur paleontology. Researchers began to recognize that dinosaur species often had much shorter geological lifespans and smaller geographic ranges than previously thought. The "lumping" philosophy of the mid-20th century gave way to "splitting," driven by rigorous phylogenetic analyses and a better understanding of stratigraphy.³

In the 2010s and 2020s, a new generation of paleontologists began revisiting the historic collections of the San Juan Basin. The catalyst for the resurrection of Reeside's specimen was a multi-institutional collaboration involving researchers from Montana State University, Harrisburg University, Penn State, the New Mexico Museum of Natural History, and international partners from the Slovak Republic.⁵

Led by paleontologist Sebastian Dalman, the team undertook a comprehensive anatomical and morphological comparison of the hadrosaurid specimens from New Mexico. They applied modern statistical methods and comparative anatomy to test whether the "Kritosaurus" fossils truly represented a single, long-lived species or a succession of distinct forms. Their analysis of USNM VP-8629 revealed a suite of unique features in the skull—particularly in the jugal and quadrate bones—that were incompatible with the diagnosis of Kritosaurus navajovius.³

The result was the formal description of Ahshislesaurus wimani in the Bulletin of the New Mexico Museum of Natural History and Science (Vol. 101), published in late 2025/early 2026.⁴ The 109-year-old fossil finally had a name.

3. Systematic Paleontology and Etymology

3.1 Taxonomic Classification

The formal classification of the new taxon places it securely within the major clades of ornithischian dinosaurs:

Rank	Taxon
Dinosauria	Owen, 1842
Ornithischia	Seeley, 1887
Ornithopoda	Marsh, 1881
Hadrosauridae	Cope, 1869
Saurolophinae	Brown, 1914
Tribe	Kritosaurini Lapparent & Lavocat, 1955
Genus	Ahshislesaurus Dalman et al., 2025
Species	Ahshislesaurus wimani Dalman et al., 2025

3.2 Etymology: The Salt and the Scholar

The scientific name Ahshislesaurus wimani is a deliberate fusion of geography, indigenous language, and scientific history.

The Genus Name: Ahshislesaurus The prefix "Ahshislepah" refers to the Ah-shi-sle-pah Wilderness Study Area, the specific locality where the holotype was discovered. This name is a phonetic transliteration of the Navajo phrase áshįįh łibá. In the Navajo language, áshįįh means "salt," and łibá means "gray." The phrase translates to "salt, it is gray," a poetic and accurate description of the region's distinctive gray mudstones and saline deposits that characterize the badlands.¹² The suffix -saurus is derived from the Ancient Greek sauros, meaning "lizard." Thus, the name can be interpreted as the "Gray Salt Lizard" or "Lizard of the Gray Salt Wash".¹⁴

The Specific Epithet: wimani The species name honors Carl Wiman (1867–1944), a seminal figure in the history of paleontology. Wiman was the first professor of paleontology in Sweden, based at Uppsala University.¹⁵ In the 1920s and 1930s, Wiman supervised the study of extensive vertebrate collections from the San Juan Basin, particularly those collected by Charles Sternberg. His early work helped lay the foundation for understanding the dinosaur fauna of New Mexico.¹⁵ By naming the species after him, the authors bridged the gap between the American field discovery and the European academic tradition that contributed to the region's study.

4. Stratigraphic and Geological Context

4.1 The Kirtland Formation

The fossil record of Ahshislesaurus is tied inextricably to the Kirtland Formation, a thick sequence of sedimentary rocks deposited during the Campanian stage of the Late Cretaceous (approximately 75 to 73 million years ago).¹⁷ The formation represents a terrestrial environment of floodplains, river channels, and swamps that lay along the retreating western margin of the Western Interior Seaway.³

The Kirtland Formation is divided into three primary members (from oldest to youngest):

1. Hunter Wash Member (Lower Kirtland)

2. Farmington Member (Middle Kirtland)

3. De-na-zin Member (Upper Kirtland)

4.2 The Hunter Wash Member: A Specific Horizon

The holotype of Ahshislesaurus was recovered from the lower Hunter Wash Member.⁵ This stratigraphic position is the "smoking gun" that initially suggested the animal might be distinct from Kritosaurus.

Radiometric dating of ash beds within the Kirtland Formation allows for precise temporal placement. The Hunter Wash Member dates to approximately 75.02 million years ago.¹⁷ In contrast, the type specimens of Kritosaurus navajovius and another related hadrosaur, Naashoibitosaurus ostromi, are found in the stratigraphically higher De-na-zin Member, which dates to approximately 73.83–73.49 Ma.¹⁵

This temporal separation of nearly 1.5 million years is significant in evolutionary time. In the dynamic ecosystems of the Late Cretaceous, dinosaur species turnover was rapid. The presence of a kritosaurin hadrosaur in the Hunter Wash Member, separated by significant geological time from the kritosaurins of the De-na-zin Member, implies a lineage of replacement rather than stasis. Ahshislesaurus represents the ancestral incumbent of this niche, flourishing more than a million years before Kritosaurus walked the same landscape.³

4.3 Depositional Environment

The sediments of the Hunter Wash Member consist largely of mudstones, siltstones, and sandstones. These fine-grained rocks indicate a low-energy depositional environment, likely the inter-channel areas of a vast river system.¹⁹ The preservation of articulated vertebrae in the holotype suggests that the animal was buried relatively quickly after death, perhaps during a flood event that covered the carcass in the "gray salt" muds that would give the animal its name millions of years later.³

5. Anatomical Description: Building the "Giant Cow"

5.1 Size and Stature

The nickname "giant cow of the Cretaceous" is an understatement of the animal's true proportions. Ahshislesaurus wimani was a behemoth. Based on the available skeletal elements, researchers estimate the total body length to be between 10 and 12 meters (33 to 39 feet).²

In terms of mass, the animal likely weighed in excess of 8,000 kilograms (8 metric tons).⁵ This places Ahshislesaurus in the upper size tier of hadrosaurids, comparable to the massive Edmontosaurus annectens and Shantungosaurus. Its robust build suggests an animal that was relatively slow-moving on land, relying on size and herd dynamics for defense against the apex predators of its time.²

5.2 Cranial Anatomy: The Diagnostic Keys

As with most dinosaur taxonomy, the devil is in the details of the skull. Hadrosaurs are generally conservative in their post-cranial skeletons—a femur of one species looks much like the femur of another. However, their skulls evolved rapidly, displaying a dizzying array of crests, arches, and specialized chewing mechanics.

The "Flat" Head Ahshislesaurus is a saurolophine, distinguishing it from the crested lambeosaurines. It lacked the hollow, trombone-like crests used for resonance. Instead, its skull was characterized by a "solid" morphology. While described as "flat-headed," it likely possessed a nasal arch structure typical of the tribe Kritosaurini. This arch, formed by the nasal bones, would have given the animal a distinctive "Roman nose" profile, although less pronounced than in Gryposaurus.²⁰

The Jugal (Cheek Bone)

The jugal bone is a critical diagnostic element in hadrosaur classification. In Ahshislesaurus, the jugal presents a unique morphology that separates it from Kritosaurus:

• Quadratojugal Flange: This part of the jugal, which articulates with the quadratojugal bone, is notably elongated and maintains a uniform width throughout its length. In contrast, this feature is often tapered or variably shaped in related genera.¹³

• Posterior Process: The rear-facing projection of the jugal is described as convex and broad. This robust construction suggests powerful cheek muscles, essential for the processing of tough vegetation.¹³

The Quadrate The quadrate bone acts as the hinge between the skull and the lower jaw. In Ahshislesaurus, the quadrate is exceptionally robust and wide in lateral view. Crucially, the dorsal (top) end of the quadrate is inclined posteriorly (leaning backward).¹³ This inclination is a key autapomorphy (unique derived character); in most other hadrosaurids, the quadrate stands vertically or leans slightly forward. This specific angle would have altered the mechanics of the jaw, potentially influencing the bite force or the range of motion during mastication.¹³

5.3 The Dental Battery

Like all hadrosaurs, Ahshislesaurus possessed one of the most sophisticated chewing mechanisms in the animal kingdom: the dental battery. This structure consisted of hundreds of interlocking teeth packed together into a solid grating surface. As the animal chewed, grinding down the occlusal surface, new teeth from deep within the jaw would migrate upward to replace the worn ones.²²

This adaptation turned Ahshislesaurus into a hyper-efficient processing machine, capable of pulverizing tough, fibrous plant matter that other herbivores could not exploit. This efficiency is likely what allowed hadrosaurs to become the dominant herbivores of the Late Cretaceous, "exploding with diversity" as noted by the research team.³

5.4 Post-Cranial Skeleton

While the skull provides the identity, the body tells the story of the animal's life.

• Cervical Vertebrae: The holotype preserves a series of articulated cervical vertebrae. These bones indicate a thick, muscular neck, necessary to support the massive head and the constant motion of feeding.³

• Limbs: Referred specimens include humeri (upper arm bones) from both an adult and a juvenile. The adult humerus is robust, indicating that the animal was quadrupedal when moving slowly or resting, but likely facultatively bipedal when running.¹⁰ The presence of a juvenile humerus is particularly valuable, as it allows paleontologists to study the ontogeny (growth) of the species, revealing how the proportions of the limbs changed as the animal matured from a hatchling to an 8-ton adult.¹⁰

6. Phylogeny and Evolutionary Relationships

6.1 The Tree of Life

The phylogenetic analysis conducted by Dalman and colleagues utilized Bayesian inference methods to determine the evolutionary position of Ahshislesaurus. The results place the new genus firmly within the Saurolophinae subfamily.¹³

Within Saurolophinae, Ahshislesaurus belongs to the tribe Kritosaurini (also known as Kritosaurini). This tribe is characterized by the nasal arch morphology. The analysis recovered Ahshislesaurus in a specific position:

• Sister Taxon: Naashoibitosaurus ostromi.

• Clade: Together with Gryposaurus alsatei and the Mexican specimen PASAC-1 ("Sabinosaurus"), they form a southern clade of kritosaurins.¹³

6.2 Separating the Siblings

The relationship with Naashoibitosaurus is particularly interesting. Naashoibitosaurus is also found in the Kirtland Formation but in the younger De-na-zin Member. The phylogenetic proximity suggests a direct evolutionary lineage or a close branching event. Ahshislesaurus likely represents the ancestral stock that gave rise to the later Kirtlandian hadrosaurs.

The distinction from Kritosaurus navajovius is now clear. While they are close relatives, they belong to distinct lineages that may have diverged earlier or represent a sequence of species replacement driven by environmental changes in the San Juan Basin.¹⁰

6.3 The Hypothesis of Laramidian Provincialism

The discovery of Ahshislesaurus provides robust support for the hypothesis of dinosaur provincialism in Laramidia. This theory posits that despite the lack of physical barriers (like mountain ranges) running east-west, the dinosaur faunas of northern Laramidia (Alaska, Alberta, Montana) were distinct from those in the south (New Mexico, Utah, Texas).¹⁰

• Northern Province: Dominated by Brachylophosaurus, Gryposaurus (northern species), and Maiasaura.

• Southern Province: Dominated by the Ahshislesaurus-Kritosaurus complex and Parasaurolophus tubicen.

The identification of a novel clade of southern saurolophines (the Ahshislesaurus + Naashoibitosaurus group) suggests that the southern fauna was evolving in isolation, perhaps driven by latitudinal climate gradients. The "greenhouse" climate of the south may have favored different feeding strategies and social behaviors, leading to the divergence of these distinct hadrosaur lineages.²¹

7. Paleoecology: The World of the Hunter Wash

7.1 Climate and Environment

The world of Ahshislesaurus was a subtropical paradise, but a wet and dynamic one. 75 million years ago, the San Juan Basin was a coastal floodplain located on the western shore of the Western Interior Seaway. The climate was warm and humid, with no winter frost. The landscape was a mosaic of large, meandering rivers, oxbow lakes, swamps, and well-drained overbank deposits.²³

7.2 The Flora: The Menu

What fueled an 8-ton herbivore? The paleobotanical record of the Hunter Wash Member gives us the menu:

• Conifers: The dominant trees were likely conifers such as Brachyphyllum. These trees had succulent, fleshy leaves, making them an ideal high-energy food source for a browsing giant.²⁴

• Angiosperms: Flowering plants were rapidly diversifying. Dicots and palms were common in the understory and along riverbanks. The broad beak of Ahshislesaurus would have been perfectly adapted for cropping large quantities of this varied vegetation.²³

• Lignite Beds: The presence of lignite (fossilized peat) in the formation indicates extensive swamp environments where aquatic plants would have thrived.²⁵

7.3 The Hunter Wash Local Fauna

Ahshislesaurus was part of a vibrant ecosystem known as the Hunter Wash Local Fauna.¹⁹ It shared its habitat with a terrifying array of neighbors.

The Predators The apex predator of this ecosystem was Bistahieversor sealeyi. This tyrannosaurid, distinct from T. rex and Albertosaurus, was a formidable hunter. With a deep skull and bone-crushing teeth, Bistahieversor was the primary threat to Ahshislesaurus. The interplay between these two species—the "Bisti Beast" and the "Giant Cow"—would have defined the predator-prey dynamics of the region.²³ Smaller predators included dromaeosaurids (raptors), which likely preyed on juvenile hadrosaurs.

The Competitors

Ahshislesaurus was not the only herbivore.

• Ceratopsians: The giant horned dinosaur Pentaceratops sternbergii is a hallmark of the Kirtland Formation. With its massive frill and five horns, it would have competed for low-growing vegetation.²⁶

• Ankylosaurs: The armored dinosaur Ahshislepelta minor (also named after the Ah-shi-sle-pah Wash) browsed the lowest vegetation, protected by its bony osteoderms.²⁷

• Pachycephalosaurs: Dome-headed dinosaurs like Stegoceras were present, occupying a niche for smaller herbivores.²⁵

The Aquatic Community The rivers were teeming with life. The Kirtland Formation is famous for its diversity of turtles (testudines), with numerous genera inhabiting the waterways. Crocodylians, including alligatoroids and the large Deinosuchus, lurked in the swamps, posing a danger to any dinosaur coming to drink.²⁵

8. Conclusion: The Legacy of USNM VP-8629

The description of Ahshislesaurus wimani is a triumph of persistence. It validates the efforts of the 1916 USGS field crew who hauled heavy fossil blocks out of the badlands on horseback. It vindicates the "splitters" of paleontology who argued that the diversity of dinosaurs was far greater than the mid-20th-century consensus allowed. And it highlights the critical importance of natural history museums as active repositories of discovery, not just mausoleums for dead things.

By distinguishing Ahshislesaurus from Kritosaurus, scientists have added a new character to the story of Late Cretaceous North America. This "giant cow" was a dominant player in the southern Laramidian ecosystem, a creature that shaped its environment through bulk feeding and provided sustenance for the tyrannosaurs of its day. Its existence proves that the San Juan Basin was a crucible of evolution, generating unique forms of life found nowhere else on the continent.

As paleontologists continue to scour the Ah-shi-sle-pah Wash and the drawers of the Smithsonian, it is certain that Ahshislesaurus will not be the last secret to be revealed. But for now, the "giant cow" has finally stepped out of the shadow of Kritosaurus and into the light of scientific recognition.

Table 1: Comparative Attributes of Kirtland Formation Hadrosaurs

Feature	Ahshislesaurus wimani	Kritosaurus navajovius	Naashoibitosaurus ostromi
Stratigraphic Member	Hunter Wash Member	De-na-zin Member	De-na-zin Member
Geological Age	~75.02 Ma	~73.5 Ma	~73.5 Ma
Cranial Morphology	Flat-headed; robust quadrate; inclined quadrate head	Arched nasal (incomplete); vertical quadrate	Arched nasal; distinct crest shape
Jugal Flange	Elongated, uniform width	Tapered or variable	Distinctive morphology
Phylogenetic Tribe	Kritosaurini	Kritosaurini	Kritosaurini
Primary Location	Ah-shi-sle-pah Wash	San Juan Basin	San Juan Basin

Table 2: Key Figures in the History of Ahshislesaurus

Name	Role	Contribution	Year of Relevance
John B. Reeside Jr.	USGS Geologist	Discovered the holotype (USNM VP-8629)	1916
Charles W. Gilmore	Paleontologist	Referred specimen to Kritosaurus navajovius	1935
Carl Wiman	Paleontologist	Pioneer of San Juan Basin studies; species namesake	1920s-1940s
Sebastian Dalman	Lead Researcher	Led the 2025/2026 re-description and naming	2025/2026

Works cited

1. Dinosaurs: News, features and articles | Live Science, accessed February 2, 2026, https://www.livescience.com/animals/extinct-species/dinosaurs

2. "Cretaceous Cow" Revealed After Nearly 100 Years: New Herbivorous Dinosaur Species Corrects Historical Error, Rewrites Hadrosaur Classification, and Expands Scientific Understanding of Prehistoric Life - Click Oil and Gas, accessed February 2, 2026, https://en.clickpetroleoegas.com.br/new-species-of-herbivorous-dinosaur-from-the-Cretaceous-period./

3. New massive duck-billed dinosaur species identified | Penn State University, accessed February 2, 2026, https://www.psu.edu/news/lehigh-valley/story/new-massive-duck-billed-dinosaur-species-identified

4. HU Professor Part of Research Team Naming New Species of Duck-Billed Dinosaur, accessed February 2, 2026, https://www.harrisburgu.edu/news/2025-10-07-new-southern-duck-billed-dinosaur-species/

5. A New Saurolophine Hadrosaur is Scientifically Described - Everything Dinosaur Blog, accessed February 2, 2026, https://blog.everythingdinosaur.com/blog/_archives/2026/01/14/a-new-saurolophine-hadrosaur-is-scientifically-described.html

6. CONTRIBUTIONS TO THE GEOLOGY AND PALEONTOLOGY OF SAN JUAN COUNTY, NEW MEXICO. - USGS Publications Warehouse, accessed February 2, 2026, https://pubs.usgs.gov/pp/0098p/report.pdf

7. John B. Reeside, Jr., Papers, 1916-1958 and undated - Smithsonian Institution Archives, accessed February 2, 2026, https://siarchives.si.edu/collections/siris_arc_217482

8. JOHN BERNARD REESIDE, JR. - Biographical Memoirs, accessed February 2, 2026, http://biographicalmemoirs.org/pdfs/reeside-john-b-jr.pdf

9. Fossil Legends of the First Americans [Course Book ed.] 9781400849314 - DOKUMEN.PUB, accessed February 2, 2026, https://dokumen.pub/fossil-legends-of-the-first-americans-course-booknbsped-9781400849314.html

10. Paleontologists Identify New Species of Flat-Headed Herbivorous Dinosaur | Sci.News, accessed February 2, 2026, https://www.sci.news/paleontology/ahshislesaurus-wimani-14265.html

11. Scientists Misidentified This Nine-Ton Giant Dinosaur for Over 100 Years - The Daily Galaxy, accessed February 2, 2026, https://dailygalaxy.com/2025/11/scientists-misidentified-giant-dinosaur/

12. accessed February 2, 2026, https://en.wikipedia.org/wiki/Ahshislesaurus#:~:text=%22Ah%2Dshi%2Dsle%2D,New%20Mexico's%20San%20Juan%20Basin.

13. Ahshislesaurus - Wikipedia, accessed February 2, 2026, https://en.wikipedia.org/wiki/Ahshislesaurus

14. (PDF) A NEW SAUROLOPHINE HADROSAURID (ORNITHISCHIA: HADROSAURIDAE) FROM THE UPPER CRETACEOUS (CAMPANIAN) HUNTER WASH MEMBER, KIRTLAND FORMATION, SAN JUAN BASIN, NEW MEXICO - ResearchGate, accessed February 2, 2026, https://www.researchgate.net/publication/396522699_A_NEW_SAUROLOPHINE_HADROSAURID_ORNITHISCHIA_HADROSAURIDAE_FROM_THE_UPPER_CRETACEOUS_CAMPANIAN_HUNTER_WASH_MEMBER_KIRTLAND_FORMATION_SAN_JUAN_BASIN_NEW_MEXICO

15. [Paleontology • 2025] Ahshislesaurus wimani • A New saurolophine hadrosaurid (Ornithischia: Hadrosauridae) from the Upper Cretaceous (Campanian) Hunter Wash Member, Kirtland Formation, San Juan Basin, New Mexico - Species New to Science, accessed February 2, 2026, http://novataxa.blogspot.com/2025/10/ahshislesaurus.html

16. Dinosaur Models - Part 2, accessed February 2, 2026, https://blog.everythingdinosaur.com/page/2

17. (PDF) The first occurrence of hadrosaur (Dinosauria) remains from the marine Claggett Formation, Late Cretaceous of south-central Montana - ResearchGate, accessed February 2, 2026, https://www.researchgate.net/publication/254313580_The_first_occurrence_of_hadrosaur_Dinosauria_remains_from_the_marine_Claggett_Formation_Late_Cretaceous_of_south-central_Montana

18. (PDF) A new saurolophine hadrosaurid (Ornithischia: Hadrosauridae) from the Upper Cretaceous (Campanian) Hunter Wash Member, Kirtland Formation, San Juan Basin, New Mexico - ResearchGate, accessed February 2, 2026, https://www.researchgate.net/publication/396005330_A_new_saurolophine_hadrosaurid_Ornithischia_Hadrosauridae_from_the_Upper_Cretaceous_Campanian_Hunter_Wash_Member_Kirtland_Formation_San_Juan_Basin_New_Mexico

19. Stratigraphy, paleontology and age of the Fruitland and Kirtland Formations (Upper Cretaceous), San Juan Basin - New Mexico Geological Society, accessed February 2, 2026, https://nmgs.nmt.edu/publications/guidebooks/downloads/43/43_p0217_p0239.pdf

20. accessed February 2, 2026, https://www.livescience.com/animals/dinosaurs/giant-cow-of-the-cretaceous-discovered-almost-100-years-ago-identified-as-new-duck-billed-dinosaur#:~:text=Scientists%20have%20discovered%20an%20enormous,researchers%20revealed%20in%20a%20study.

21. Ahshislesaurus - Total Dino, accessed February 2, 2026, https://www.totaldino.com/dino/ahshislesaurus

22. The internal anatomy of the hadrosaurid dental battery. a artist's... | Download Scientific Diagram - ResearchGate, accessed February 2, 2026, https://www.researchgate.net/figure/The-internal-anatomy-of-the-hadrosaurid-dental-battery-a-artists-reconstruction-of-a_fig5_305697037

23. A New Tyrant Dinosaur from the Late Campanian of Mexico Reveals a Tribe of Southern Tyrannosaurs - MDPI, accessed February 2, 2026, https://www.mdpi.com/2813-6284/2/4/12

24. Review of taxonomy, geographic distribution, and paleoenvironments of Azhdarchidae (Pterosauria) - PMC - PubMed Central, accessed February 2, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC4141157/

25. AH-SHI-SLE-PAH WILDERNESS STUDY AREA (SAN JUAN BASIN, NEW MEXICO): A PALEONTOLOGICAL (AND HISTORICAL) TREASURE AND RESOURCE, accessed February 2, 2026, http://www.aztecnm.com/recreation/ahshislepah/AhShiSlePahWilderness-Sullivan.pdf

26. New duck-billed dinosaur species identified in northwest New Mexico - YouTube, accessed February 2, 2026, https://www.youtube.com/watch?v=IBuM9D0Ck30

27. List of thyreophoran type specimens - Wikipedia, accessed February 2, 2026, https://en.wikipedia.org/wiki/List_of_thyreophoran_type_specimens