The Rise of Reptiles sample pages from Johns Hopkins University Press

The defining

THE R IS E O F R E P T I LE S

320 MILLION YEARS OF EVOLUTION

masterwork on the evolution of reptiles.

HANS-DIETER SUES

The Rise of Reptiles 320 Million Years of Evolution HANS-DIETER SUES Over 300 million years ago, an early land vertebrate developed

first detailed, contemporary synthesis of the evolutionary

an egg that contained the embryo in an amnion, allowing it to

history of these remarkable animals. Reptiles have always

be deposited on land. This moment marked the first step in the

confused taxonomists, who have endlessly debated and

fascinating and complex evolutionary journey of the reptiles.

rewritten their classifications. In this book, Sues adopts an

In The Rise of Reptiles, paleontologist Hans-Dieter Sues explores

explicitly phylogenetic framework to sift through the evidence

the diversity of reptilian lineages, discussing the relationships

and discuss the origin and diversification of Reptilia in a way no

among turtles, crocodylians, lizards and snakes, and many

one has before. He also examines the genealogical link between

extinct groups.

dinosaurs and birds and sheds new light on the Age of Reptiles,

Reflecting the tremendous advances in the study of reptilian diversity and phylogeny over recent decades, this book is the

a period that saw the rise and fall of most dinosaurs.

Accurate, synthetic, and sweeping, The Rise of Reptiles is the definitive work on the subject.

Table of Contents Preface Outline Classification 1. Introduction 2. Amniotes and Reptiles 3. Parareptilia: A Group of Their Own 4. Basal Eureptilia and Nonsaurian Diapsida: Early Evolution of Modern Reptiles 5. Testudinata: Turtles and Their Stem-Taxa 6. Sauropterygia, Ichthyosauromorpha, and Related Reptiles: The Early Mesozoic Invasion of the Sea 7. Lepidosauromorpha: Tuatara, Lizards, Snakes, and Their Relatives 8. Archosauromorpha: The Ruling Reptiles and Their Relatives 9. Pseudosuchia: Crocodile-Line Reptiles 10. Avemetatarsalia: Bird-Line Reptiles 11. Dinosauria: Saurischia 12. Dinosauria: Ornithischia 13. A Brief History of Reptiles

• Specimens from around the world introduce the reptilian fossil record

14. The Future of Reptiles

• Color images of present-day reptiles illustrate their diversity

Index

• The extensive bibliography invites readers to explore individual topics more deeply

Glossary References

Hans-Dieter Sues is a senior scientist and curator of fossil vertebrates at the Smithsonian’s National Museum of Natural History. He is the coauthor of Triassic Life on Land: The Great Transition.

176

The Rise of Reptiles

Figure 8.24. Comparison of A, “crocodile-normal,” and B, mesotarsal ankle joint. Both are shown in lateral and dorsal view. Red line indicates zone of flexion. Courtesy of Jeff Martz.

lateral surface of the jugal, and the presence of more than one pair of dorsal osteoderms per vertebra (Stocker et al. 2017). It was found in nearshore marine deposits.

Parasuchidae comprises the most recent common ancestor of Wannia scurriensis, Parasuchus hislopi, and Mystriosuchus planirostris, and all descendants of that ancestor (Stocker et al. 2017). The best-known basal representative is Parasuchus, from the Late Triassic (Carnian-Norian) of Germany, India, Morocco, and Poland as well as Pennsylvania, Texas, and Wyoming (Kammerer et al. 2015). Another basal taxon, Ebrachosuchus, from the Late Triassic (Carnian) of Germany (Fig. 8.22), differs from Parasuchus especially in the much greater elongation of the snout and higher tooth count (Kammerer et al. 2015). Derived parasuchids share the more posterior position of the external nares relative to the antorbital fenestrae (Stocker and Butler 2013; Fig. 8.23). Smilosuchus, from the Late Triassic (Norian) of Arizona, attained skull lengths of well over 1 m and a total length of more than 7 m (Camp 1930; Long and Murry 1995). Although most parasuchids lived near or in freshwater, at least Mystriosuchus ventured into lagoonal and coastal marine settings (Gozzi and Renesto 2003).

For many years the structure of the ankle was considered a key diagnostic feature uniting crocodylians, most other pseudosuchians, and phytosaurs. The crurotarsal or “crocodile-normal” ankle (Fig. 8.24) is characterized by a distinct process on the astragalus that fits into a deep socket and contacts an adjacent bony flange on the calcaneum, facilitating considerable motion between these two tarsal bones (Krebs 1963, 1974; Thulborn 1980; Chatterjee 1982; Sereno and Arcucci 1989; Sereno 1991a). If the pes is flexed dorsally, the astragalus functions as part of the distal portion of the leg (crus). The calcaneum, together with the distal tarsals and the pes, can rotate on the astragalus through an arc of about 45 degrees (Fig. 8.24A). It bears a prominent tuber with an expanded distal end that bears a vertical groove for the tendons of the gastrocnemius, the major flexor muscle of the foot, and increases the leverage of that muscle (C. Sullivan 2015). In most other reptiles, the ankle joint extends between the proximal and distal tarsals (mesotarsal ankle: Fig. 8.24B). However, recent discoveries have established that even basal members of the avemetatarsalian lineage have a “crocodile-normal” ankle structure (see Chapter 10).

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9

Pseudosuchia Crocodile-Line Archosaurs

Chapters reflect the tremendous advances in the study of reptilian diversity and phylogeny over recent decades.

Archosauria (from Greek archon, ruler, and sauros, lizard) is the least inclusive clade containing Crocodylus niloticus (Nile crocodile) and Passer domesticus (domestic sparrow) (Sereno 2005). Nesbitt (2011) listed a suite of shared derived features for this crown group including a contact between the palatal processes of the maxillae along the midline of the cranium; lagenar (cochlear) recess elongate and tubular; antorbital fossa on the lacrimal and portions of the maxilla; posteroventral portion of the coracoid “swollen”; and a divided tibial facet on the astragalus. The oldest undisputed archosaur known to date is Xilousuchus, from the Early Triassic (Olenekian) of Shanxi (China) (Nesbitt et al. 2011).

Pseudosuchia Gauthier and Padian (1985) distinguished two principal lineages among Archosauria, one leading to crocodylians (Fig. 9.1) and the other leading to birds. The former is named Pseudosuchia (from Greek pseudes, false, and souchos, crocodile) and is defined as the most inclusive clade containing Crocodylus niloticus but not Passer domesticus (Sereno 2005).

Pseudosuchia: Suchia Suchia (from Greek souchos, crocodile) is the least inclusive clade containing Ornithosuchus woodwardi, Tarjadia ruthae, Aetosaurus ferratus, Rauisuchus tiradentes, Prestosuchus chiniquensis, and Crocodylus niloticus (modified from Nesbitt [2011]). Krebs (1974) originally proposed this name for Crocodylia and other pseudosuchians with a “crocodilenormal” ankle.

Pseudosuchia: Suchia: Ornithosuchidae Ornithosuchidae comprises the most recent common ancestor of Ornithosuchus, Riojasuchus, and Venaticosuchus and all descendants of that ancestor (Sereno 1991a). It is known from the Late Triassic (Carnian-Norian) of Argentina and the Late Triassic of Scotland.

This clade is characterized by various derived cranial features including a bulbous and slightly ventrally deflected anterior end of the snout, the presence of a distinct gap (diastema) between the premaxillary and maxillary teeth, and the tapered ventral end of the orbit bounded by the dorsal processes of the jugal (Sereno 1991a; Nesbitt 2011; Baczko and Ezcurra 2013; Ezcurra 2016; Fig. 9.2). The pelvis has a perforated acetabulum. The tarsus of ornithosuchids is unique among pseudosuchians in the presence of a peg on the calcaneum that fits into a concavity on the astragalus (“crocodile-reverse” ankle; Chatterjee 1982). Ornithosuchus, from the Late Triassic of Scotland, attained a

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Hundreds of of Reptiles 60 The Rise illustrations allow readers to compare the fossil record to living reptiles.

Figure 5.21. Shell of the eucryptodiran Craspedochelys jaccardi in A, dorsal, and B, ventral views. Red lines represent furrows for scutes. From Anquetin et al. (2014)—CC BY 4.0.

bridging between the carapace and plastron. At least some carapacial scutes and all plastral scutes are lacking.

The entoplastron is boomerang-shaped. The distinctive external sculpturing (Figs. 5.25, 5.26) and characteristic “plywood” microstructure allow identification of even small fragments of trionychian shells (Holroyd and J. H. Hutchinson 2002; Scheyer et al. 2007).

Joyce et al. (2004) proposed Pan-Carettochelys for the total group that includes the extant Carettochelys insculpta (pig-nosed turtle; Fig. 5.24A). This clade is characterized by a number of derived features such as the presence of a shallow fossa behind the quadrate, the presence of only 10 peripheral scutes, and the reduction of plastral scutes (Joyce 2014). Kizylkumemys, from the Early Cretaceous

(Aptian) of Thailand and the Late Cretaceous (Cenomanian) of Uzbekistan, is its oldest known representative (Joyce 2014). Carettochelyidae comprises the most recent common ancestor of Carettochelys insculpta and Anosteira ornata and all descendants of that ancestor (Joyce et al.

2004). Anosteira is known from the Paleogene (Eocene) of Utah and Wyoming, Guandong and Liaoning (China), and Mongolia (Joyce 2014). Its shell differs from those of other carettochelyids particularly in the presence of carapacial scutes. Carettochelyinae includes Carettochelys, from Australia and Papua New Guinea (Fig. 5.24A), and Allaeochelys, from the Paleogene (Eocene) of Belgium, England, France, Germany, Myanmar, and Spain, the Paleogene of Guandong (China), and the Neogene (Mio-

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Testudinata 61

Figure 5.23. Phylogenetic hypothesis of extant cryptodiran turtles. Dots denote node-based clades. Based mainly on Joyce (2007) and Joyce et al. (2013).

Figure 5.22. Skeleton of the eucryptodiran Eurysternum wagleri in ventral view. Note the reduction of the bony shell. Courtesy of Jérémy Anquetin.

cene) of Libya (Joyce 2014). It is characterized by the absence of carapacial and plastral scutes in adult individuals, a transversely broad plastron, and the presence of a deep fossa behind the quadrate (Joyce 2014). Carettochelys attains a shell length of up to about 60 cm.

Pan-Trionychidae is diagnosed by various synapomorphies including the exclusion of the fused premaxillae from the external narial aperture; the absence of a contact between the quadratojugal and the maxilla or postorbital; all metaplastic portions of the shell with superficial ornamentation; the absence of peripherals, pygals, and suprapygals; absence of scutes on the shell; entoplastron boomerang-shaped; absence of articulation between the centra of the eighth cervical and first dorsal vertebra; hyperphalangy of the manus and pes; and the presence of three claws on each manus and pes (Vitek and Joyce 2015). Perochelys, from the Early Cretaceous (Aptian) of Liaoning (China), is the oldest wellknown pan-trionychid and already closely resembles more derived members of this clade in its skeletal structure (L. Li et al. 2015). Pan-Trionychidae has a rich fossil

Figure 5.24. Extant representatives of Trionychia. A, pig-nosed turtle (Carettochelys insculpta); B, Chinese softshell turtle (Trionyx sinensis). A, courtesy of Laurie Vitt; B, courtesy of Division of Amphibians and Reptiles, National Museum of Natural History.

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The Rise of Reptiles

T HE R ISE O F R E PTIL E S

320 Million Years of Evolution HANS-DIETER SUES

320 MILLION YEARS OF EVOLUTION

HANS-DIETER SUES

Publication date: August, 2019 8½ x 11, 400 pages 236 color illus., 120 b&w illus.

978-1-4214-2867-3 $84.95 / £63.00 hardcover Also available as an e-book

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