The Origin and Evolution of Mammals - Moodle

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LIVING AND FOSSIL MARSUPIALS 211 M 2 me me.d Pa.d (a) (b) (f) (d) Yalkaparidon Yarala Ankotarinja Badjcinus (e) (c) Barinya Figure 6.11 Extinct Australian marsupials. Yalkaparidon coheni: (a) Skull in side view, and (b) occlusal views of upper (left) and lower (right) molars (redrawn after Long et al. 2002). (c) The peramelemorphian Yarala: fragment of lower jaw with 3rd premolar and molars (after Long et al. 2002), and two upper molars in occlusal view (Muirhead and Filan 1995). (d) The basal dasyuromorph Ankotarinja upper molar in occlusal view (Savage and Long 1986). (e) Skull of the earliest dasyurid Barinya wangali in lateral, dorsal, and ventral lateral views (Wroe 1999). (f) Lateral view of the lower jaw of the basal thylacine Badjcinus. Length of fragment approx. 6 cm (after Muirhead and Wroe 1998). Pr.d M 2
212 THE ORIGIN AND EVOLUTION OF MAMMALS and open-rooted so they were continuously growing. The molars have evolved a highly specialised form, described as zalambdodont, by losing the protocone from the uppers and the talonid from the lowers, and developing a V-shaped crest between the high, sharp remaining cusps. The resulting occlusal surface is crescentic in shape, and resembles the teeth of several placental groups such as tenrecs and golden moles. There is also a superficial similarity to the zalambdodont-like molars of the marsupial mole, although no other evidence points to a relationship of yalkaparidonts to the latter. Judging from the molars, the diet consisted of soft invertebrates, but the role in feeding of the gross incisors is hard to decipher. Archer et al. (1991) suggested that the food consisted of invertebrates that required puncturing by the front teeth, but were then easy to masticate with the simple transverse crests of the molars. Earthworms and beetle grubs would be candidates. The postcranial skeleton is as yet unknown, so it cannot be said whether Yalkaparidon had the digging adaptations that would be expected in an animal with such a food preference. Extinct Peramelemorphia Some molecular evidence points to the possibility of the bandicoots and bilbies being the sister group of the rest of the Australidelphia, although this view does not gain any support from their fossil record. Apart from the possible but very doubtful peramelemorph teeth from Tingamarra, the earliest and most primitive known member is Yarala (Fig. 6.11(c)) from Riversleigh (Muirhead 2000). During the Late Oligocene and Miocene, peramelemorphs were actually the most abundant marsupial group. There were around a dozen species, all members of the family Yaralidae, and they constituted the majority of the small, mouse-sized omnivore/carnivore guild of mammals (Archer et al. 1991). The living genera of the modern family Peramelidae did not start to appear until the Pliocene (Rich 1991). So far, peramelemorphs are not represented in the fossil record of either South America or Antarctica. Extinct Dasyuromorphia There are certain mouse-sized Riversleigh specimens such as Keeura and Ankotarinja (Fig. 6.11(c)) that were considered to be primitive members of the Dasyuromorphia (Wroe 1996), and indeed they may well be correctly assigned to that group. However, they are known only from jaw fragments and isolated teeth, and Archer (1982) and Godthelp et al. (1999) have claimed that the teeth of these genera cannot actually be distinguished from didelphid teeth, as is the case for the Tingamarran Djarthia. Didelphid and basal dasyuromorph molars both exhibit the dilambdodont condition superimposed upon a basic marsupial tooth structure, including a complete set of five welldeveloped stylar cusps. Therefore, the possibility exists that these Late Oligocene/Miocene taxa are surviving members of a presumably paraphyletic Didelphimorphia, from which the dasyuromorphs had arisen. More material is required to be sure one way or the other. The earliest indisputable dasyuromorph, indeed member of the surviving family Dasyuridae is also from Riversleigh. Barinya (Fig. 6.11(e)) is well known from a complete skull which has a number of characters unique to the living dasyurids, and several jaws (Wroe 1999). As a group the Oligocene– Miocene dasyurids were less diverse than they are today, and it has been suggested that this is related to competition from the relatively more abundant bandicoots and thylacines. The Thylacinidae in contrast were more diverse then, being represented by at least six genera in the Late Oligocene to Early Miocene, ranging in size from that of a cat to that of a large dog (Muirhead 1997). Badjcinus (Fig. 6.11(f)) is the most plesiomorphic form, with a number of primitive features of molar morphology compared to other thylacinids, such as the wide-angled rather than straight centrocrista and the relatively unreduced metaconid (Muirhead and Wroe 1998). By the Late Miocene onwards diversity of thylacinids had declined and only the modern genus Thylacinus existed, and even it occurred only as a single species at any one time. The family had effectively been replaced by the larger of the dasyurids, such as the quolls Dasyurus, and the Tasmanian devils Sarcophilus. The third living family of dasyuromorphs, the numbats or Myrmecobiidae, are as yet unknown as fossils, prior to the Pleistocene occurrence of the living species.
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The Origin and Evolution of Mammals
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The Origin and Evolution of Mammals
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Preface This book arose from twin a
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For Mal /gosia with love and thanks
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Contents 1 Introduction The definit
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CHAPTER 1 Introduction There are ab
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transversely occluding molar teeth
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the Mesozoic mammals, is to do with
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a hierarchy of committees under the
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it means that a 200 Ma igneous rock
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een a more fundamental impact than
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Table 2.3 Classification of marsupi
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(a) (b) (c) humerus radius aquatic
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(a) Westlothiana Limnoscelis PO Wes
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the ankle bones to form an astragal
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(b) (c) (a) Casea rutena Casea broi
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(Fig. 3.2(f)), is actually an ophia
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the first one is enlarged, often to
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Even at their initial appearance in
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(a) Nikkasaurus (b) (d) Reiszia (e)
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Nikkasauridae The family Nikkasauri
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has figured large in discussions of
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(c) Figure 3.9 (continued). Syodon
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a mixture of progressively more spe
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animal with interdigitating, but no
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(e) (a) Anomocephalus Ulemica (b) S
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mandibulae musculature. This, as in
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To date the postcranial skeleton of
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ecognised four subgroups, based mai
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the presence of a deep, longitudina
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collected from the Lystrosaurus Ass
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(a) (d) (c) (b) Leontocephalus V PA
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(a) (c) Lycosuchus Oliveria (d) EVO
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separate families. Lycosuchidae (Fi
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consist of a large labial cusp and
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Procynosuchus (d) Procynosuchus (a)
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They constitute the monophyletic gr
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Although there is no mammal-like co
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Cynognathidae Cynognathus (Fig. 3.2
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(e) (f) Figure 3.22 (continued). Ma
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(c) (d) (a) (b) Kayentatherium EVOL
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Pachygenelus (e) (a) (c) Therioherp
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palatal, and orbitosphenoid bones,
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Wible and Hopson 1993). The interor
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published a cladogram based on rece
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310-320 Ma. By this time, the great
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are forms such as Casea itself, var
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lakes and swamps in the low-lying l
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urrowing and subsisting on a diet o
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Eothyris Haptodus sphenacodontine B
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z (a) (c) a.pt.m. M B PO P P SQ P M
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(b) a.pt.m. temp.m. a.pt.m. temp.m.
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the dentary bone above the level of
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the therocephalian grade was not on
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A balance was also achieved in the
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Locomotion Ancestral amniote grade
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screw-shaped: the front part faces
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For the recovery phase, the relativ
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SC PRC p.i.f.i tr.min (c) dp.cr ect
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the therocephalian pelvis and hindl
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spc s.sp s.sp SC PRC (d) delt T AST
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no significant novelties to what ha
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(a) (c) (e) (g) D D ex. au.m C tym
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(a) (c) (d) PMX (f) V n.turb mx.tur
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ol.b (a) (b) cer.hem gorgonopsian t
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(a) (b) (i) (ii) (iii) (iv) (v) a g
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cold stress, the part that usually
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conducted the experiment of wrappin
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mammals themselves that the enlarge
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elevation of maximum aerobic activi
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a mammal. The difficulty with all s
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collection, ingestion, and assimila
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were edaphosaurid and caseid pelyco
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CHAPTER 5 The Mesozoic mammals The
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(a) (d) AL condylar foramina are se
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evidence to relate the haramiyidans
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postcranial skeleton, and Graybeal
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side of the head can be in action a
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the lower molars is relatively high
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morganucodontan teeth. However, des
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adjacent lower molars. A small exte
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(a) (b) (d) P4 P4 Plagiaulax P4 Pau
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American Morrison Formation genus C
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a self-sharpening property. As the
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near parasagittal gait (Fig. 5.11(e
Page 172 and 173: pass through the birth canal. Relat
Page 174 and 175: (a) 1 (b) (d) me (c) me.d 3 styl st
Page 176 and 177: (a) (c) Henkelotherium Crusafontia
Page 178 and 179: pubis is excluded from the acetabul
Page 180 and 181: Cretaceous, (Aptian or Albian) of M
Page 182 and 183: eautifully preserved placentals fro
Page 184 and 185: subsequent specimens revealed that
Page 186 and 187: Minimal divergence of tribosphenida
Page 188 and 189: (c) (a) M 1 M 1 M 2 Steropodon M 2
Page 190 and 191: (b) (a) (c) pa.d pr.d me.d Ambondro
Page 192 and 193: crown-group therians) is accepted b
Page 194 and 195: form of the tooth, must reflect sub
Page 196 and 197: of feasibility that a taxon of endo
Page 198 and 199: mammals, by creating environmental
Page 200 and 201: the 11 species of marsupial, of whi
Page 202 and 203: (d) (a) pa A Dasyuromorphia B C pr
Page 204 and 205: earing two huge claws on digits thr
Page 206 and 207: that contains the independent ances
Page 208 and 209: (b) (d) (a) Glasbius Alphadon (c) D
Page 210 and 211: elieved to be Late Cretaceous in ag
Page 212 and 213: (Fig. 6.5(c)). The dentition exhibi
Page 214 and 215: (d) Figure 6.6 (continued). Thylaco
Page 216 and 217: (a) (c) Caroloameghina and Procarol
Page 218 and 219: (a) (e) (d) Proargyrolagus Groeberi
Page 220 and 221: (a) (b) Djarthia Thylacotinga (c) (
Page 224 and 225: Extinct Notoryctemorphia At present
Page 226 and 227: (f) (g) Wakaleo Diprotodon optatum
Page 228 and 229: fossil mammals, which might help cl
Page 230 and 231: 30 40 50 60 Figure 6.13 Southern Go
Page 232 and 233: the Diprotodontia also included gen
Page 234 and 235: 1. Placentalia 2. Edentata 3. Epith
Page 236 and 237: effectively absent. However, increa
Page 238 and 239: Asioryctes (a) (b) (d) Cimolestes p
Page 240 and 241: and Prokennalestes, although it doe
Page 242 and 243: (a) Leptictidium Palaeoryctidans we
Page 244 and 245: (a) Purgatorius (c) are part of the
Page 246 and 247: (a) (d) (e) (g) Protoungulatum Meso
Page 248 and 249: (a) (f) (e) Hyopsodus Phenacodus (d
Page 250 and 251: Titanoides (pantodont) (a) (c) (b)
Page 252 and 253: (a) (b) (d) Trogosus (tillodont) Es
Page 254 and 255: Mioclaenus Paulacoutoia (didolodont
Page 256 and 257: their presence. The five orders may
Page 258 and 259: Xenungulata. Only two Late Palaeoce
Page 260 and 261: (a) (b) (d) (c) Oxyaena Patriofelis
Page 262 and 263: continuously growing, and form a gr
Page 264 and 265: navicular facet, 19 or more thoraci
Page 266 and 267: (a) (c) Phosphatherium Numidotheriu
Page 268 and 269: coexist with other characters that
Page 270 and 271: The salient feature of Widanelfasia
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1 (a) 1. Perissodactyla 2. Titanoth
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(a) (b) BUNODONTIA or SUIFORMES SUI
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time, which suggests that it was on
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condition. This particular combinat
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etween Primates, Dermoptera (colugo
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have postcranial adaptations for ar
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undoubtedly related at a supraordin
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indisputably to occur prior to the
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The Late Cretaceous mammal record i
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interordinal divergences in the Lat
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diversity on Earth (Janis 1993). Fu
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effect of the surrounding sea. Trop
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was high. It lasted from 5 to 3 Ma
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and thus remain in their preferred
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agreement about exactly when within
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References Abdala, F. Redescription
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Ax, P. 1987. The phylogenetic syste
Page 306 and 307:
Bramble, D. M. 1978. Origin of the
Page 308 and 309:
Colbert, E.H. 1948. The mammal-like
Page 310 and 311:
Duvall, D. 1986. A new question of
Page 312 and 313:
Gow, C.E. 1980. The dentitions of t
Page 314 and 315:
Ivakhnenko, M.F. 1990. The late Pal
Page 316 and 317:
Kemp, T.S. 1988a. A note on the Mes
Page 318 and 319:
cladogenesis in dasyurid marsupials
Page 320 and 321:
(eds) Evolution of Tertiary mammals
Page 322 and 323:
McKenna, M.C. and Bell, S.K. 1997.
Page 324 and 325:
(ed) The phylogeny and classificati
Page 326 and 327:
Ray, S. 2000.Endothiodont dicynodon
Page 328 and 329:
Rubidge, B.S., Kitching, J.W., and
Page 330 and 331:
Simpson, G.G. 1970. The Argyrolagid
Page 332 and 333:
Thewissen, J.G.M. 1990. Evolution o
Page 334 and 335:
Novacek, M.J., and McKenna, M.C. (e
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Index Note: Page numbers in italics
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Equoidea 262 Equus 262 Erethizon 28
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Overkill hypothesis 289, 290 Oxyaen
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Tulerpeton 14, 18 Tylopoda 264 Ukha
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The Origin and Evolution of Mammals - Moodle

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