The Origin and Evolution of Mammals - Moodle

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Nikkasauridae The family Nikkasauridae was established by Ivakhnenko (2000b) for a number of small, primitive therapsids discovered in the Mezen’ River localities (Fig. 3.7(a) and (b)). The skull of Nikkasaurus itself is only about 4.5 cm in length. As befits such a small animal, the orbits are relatively huge. Its primitive nature is shown by the small, antero-posteriorly narrow temporal fenestra, the sclerotic ring of bones around the eye, and the possibly still mobile basipterygoid articulation. The dentition, however, is specialised with a long series of small, more or less equally sized teeth and no distinct canine. The cheek teeth are characterised by the development of an anterior and a posterior accessory cusp on the laterally compressed crown. They resemble those of certain later therocephalians, as indeed does the lower jaw. Its slender nature, relatively huge reflected lamina of the angular, and low coronoid process of the dentary all contribute to this impression. At any event, the Nikkasauridae would appear to be adapted to insectivory, adding yet another ecotype to the early therapsid radiation. Niaftasuchus Yet another mysterious taxon has been described by Ivakhnenko (1990). Niaftasuchus is based on a small, incomplete skull lacking the lower jaw (Fig. 3.7(c)), that was also discovered in the Mezen’ River locality. Like the nikkasaurids, its primitive nature is indicated by the small temporal fenestra, although there is little other resemblance between them. The upper dentition consists of three well-developed incisors, four smaller precanines, a larger canine, and then a series of laterally compressed postcanine teeth decreasing in size backwards along the tooth row. Ivakhnenko himself interpreted Niaftasuchus as a herbivorous dinocephalian, but Battail and Surkov (2000) suggested that it is a relative of the biarmosuchians. The material is not really adequate to support either contention; it is just as likely to be yet another early diverging specialist herbivore within the initial therapsid radiation. Biarmosuchia The most pelycosaur-like and basal therapsids date from the Late Kazanian and Early Tatarian of the EVOLUTION OF MAMMAL-LIKE REPTILES 31 lower part of the Late Permian, coming mostly from the classic localities of Mezen’, Ezhovo (Ocher) and Isheevo (Modesto and Rybczynski 2000). The exact temporal and palaeoenvironmental relationships of these various localities are not entirely certain yet, but the whole sequence is referred to by Golubev (2000) as the Dinocephalian Superassemblage. Biarmosuchus tener (Fig. 3.8(a)), is well known from a number of skulls and partial postcranial skeletons described by Sigogneau and Chudinov (1972) and more recently by Ivakhnenko (1999). The skull bears a striking resemblance to a sphenacodontid pelycosaur due to the strongly convex dorsal margin, and wide but short intertemporal region. However, the temporal region differs from the pelycosaur in the relatively larger temporal fenestra that has expanded both dorsally and ventrally compared to the pelycosaur, and in the more or less vertical orientation of the occipital plate. The single canine of Biarmosuchus is very much larger than the other teeth and the simple-pointed postcanines are reduced in relative size. The incisor teeth could probably interdigitate, lowers between uppers. There is a sclerotic ring of bones in the orbit, a feature unknown in pelycosaurs or the vast majority of therapsids. Only isolated bones of the postcranial skeleton have yet been described and no full reconstruction attempted. What is known is that the shoulder girdle is very narrow with a simple glenoid, and in the pelvic girdle the ilium extends forwards. The limb bones are long, gracile, and lack the broadly expanded ends characteristic of pelycosaurs. A second genus of primitive carnivorous therapsid to consider is Eotitanosuchus. It was described from a single crushed skull, incomplete posteriorly, that was found in the Ezhovo (Ocher) locality along with another supposed specimen. It occurs with most of the known Biarmosuchus material, to which it bears a strong resemblance, although the several authors who have studied the specimen, from Chudinov’s (1960) original account, through Sigogneau-Russell and Chudinov (1972), to Hopson and Barghusen (1986) all found differences. The main one concerned the form of the temporal fenestra, described in Eotitanosuchus as larger and showing indications of the invasion of the postorbital region by jaw musculature. One or two minor dental differences have also been pointed out. Despite the very limited material of Eotitanosuchus, the genus
32 THE ORIGIN AND EVOLUTION OF MAMMALS (a) Biarmosuchus (d) (c) (b) Ictidorhinus Lemurosaurus Proburnetia Figure 3.8 Biarmosuchians. (a) Skull of Biarmosuchus tener in lateral, posterior, dorsal and ventral views. (Ivakhnenko 1999). (b) Skull of Ictidorhinus angusticep in lateral and dorsal views (Kemp 1982). (c) Skull of Lemurosaurus pricei (Sidor and Welman 2003). (d) Skull of Proburnetia viatkenensis in lateral and dorsal views (Rubidge and Sidor 2002).
Page 2 and 3: The Origin and Evolution of Mammals
Page 4 and 5: The Origin and Evolution of Mammals
Page 6 and 7: Preface This book arose from twin a
Page 8 and 9: For Mal /gosia with love and thanks
Page 10 and 11: Contents 1 Introduction The definit
Page 12 and 13: CHAPTER 1 Introduction There are ab
Page 14 and 15: transversely occluding molar teeth
Page 16 and 17: the Mesozoic mammals, is to do with
Page 18 and 19: a hierarchy of committees under the
Page 20 and 21: it means that a 200 Ma igneous rock
Page 22 and 23: een a more fundamental impact than
Page 24 and 25: Table 2.3 Classification of marsupi
Page 26 and 27: (a) (b) (c) humerus radius aquatic
Page 28 and 29: (a) Westlothiana Limnoscelis PO Wes
Page 30 and 31: the ankle bones to form an astragal
Page 32 and 33: (b) (c) (a) Casea rutena Casea broi
Page 34 and 35: (Fig. 3.2(f)), is actually an ophia
Page 36 and 37: the first one is enlarged, often to
Page 38 and 39: Even at their initial appearance in
Page 40 and 41: (a) Nikkasaurus (b) (d) Reiszia (e)
Page 44 and 45: has figured large in discussions of
Page 46 and 47: (c) Figure 3.9 (continued). Syodon
Page 48 and 49: a mixture of progressively more spe
Page 50 and 51: animal with interdigitating, but no
Page 52 and 53: (e) (a) Anomocephalus Ulemica (b) S
Page 54 and 55: mandibulae musculature. This, as in
Page 56 and 57: To date the postcranial skeleton of
Page 58 and 59: ecognised four subgroups, based mai
Page 60 and 61: the presence of a deep, longitudina
Page 62 and 63: collected from the Lystrosaurus Ass
Page 64 and 65: (a) (d) (c) (b) Leontocephalus V PA
Page 66 and 67: (a) (c) Lycosuchus Oliveria (d) EVO
Page 68 and 69: separate families. Lycosuchidae (Fi
Page 70 and 71: consist of a large labial cusp and
Page 72 and 73: Procynosuchus (d) Procynosuchus (a)
Page 74 and 75: They constitute the monophyletic gr
Page 76 and 77: Although there is no mammal-like co
Page 78 and 79: Cynognathidae Cynognathus (Fig. 3.2
Page 80 and 81: (e) (f) Figure 3.22 (continued). Ma
Page 82 and 83: (c) (d) (a) (b) Kayentatherium EVOL
Page 84 and 85: Pachygenelus (e) (a) (c) Therioherp
Page 86 and 87: palatal, and orbitosphenoid bones,
Page 88 and 89: Wible and Hopson 1993). The interor
Page 90 and 91: published a cladogram based on rece
Page 92 and 93:
310-320 Ma. By this time, the great
Page 94 and 95:
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
Page 150 and 151:
(a) (d) AL condylar foramina are se
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evidence to relate the haramiyidans
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postcranial skeleton, and Graybeal
Page 156 and 157:
side of the head can be in action a
Page 158 and 159:
the lower molars is relatively high
Page 160 and 161:
morganucodontan teeth. However, des
Page 162 and 163:
adjacent lower molars. A small exte
Page 164 and 165:
(a) (b) (d) P4 P4 Plagiaulax P4 Pau
Page 166 and 167:
American Morrison Formation genus C
Page 168 and 169:
a self-sharpening property. As the
Page 170 and 171:
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
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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
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(c) (a) M 1 M 1 M 2 Steropodon M 2
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(b) (a) (c) pa.d pr.d me.d Ambondro
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crown-group therians) is accepted b
Page 194 and 195:
form of the tooth, must reflect sub
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of feasibility that a taxon of endo
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mammals, by creating environmental
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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
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that contains the independent ances
Page 208 and 209:
(b) (d) (a) Glasbius Alphadon (c) D
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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
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(a) (c) Caroloameghina and Procarol
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(a) (e) (d) Proargyrolagus Groeberi
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(a) (b) Djarthia Thylacotinga (c) (
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LIVING AND FOSSIL MARSUPIALS 211 M
Page 224 and 225:
Extinct Notoryctemorphia At present
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(f) (g) Wakaleo Diprotodon optatum
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fossil mammals, which might help cl
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30 40 50 60 Figure 6.13 Southern Go
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the Diprotodontia also included gen
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1. Placentalia 2. Edentata 3. Epith
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effectively absent. However, increa
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Asioryctes (a) (b) (d) Cimolestes p
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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
Page 272 and 273:
1 (a) 1. Perissodactyla 2. Titanoth
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(a) (b) BUNODONTIA or SUIFORMES SUI
Page 276 and 277:
time, which suggests that it was on
Page 278 and 279:
condition. This particular combinat
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etween Primates, Dermoptera (colugo
Page 282 and 283:
have postcranial adaptations for ar
Page 284 and 285:
undoubtedly related at a supraordin
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indisputably to occur prior to the
Page 288 and 289:
The Late Cretaceous mammal record i
Page 290 and 291:
interordinal divergences in the Lat
Page 292 and 293:
diversity on Earth (Janis 1993). Fu
Page 294 and 295:
effect of the surrounding sea. Trop
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was high. It lasted from 5 to 3 Ma
Page 298 and 299:
and thus remain in their preferred
Page 300 and 301:
agreement about exactly when within
Page 302 and 303:
References Abdala, F. Redescription
Page 304 and 305:
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
Page 336 and 337:
Index Note: Page numbers in italics
Page 338 and 339:
Equoidea 262 Equus 262 Erethizon 28
Page 340 and 341:
Overkill hypothesis 289, 290 Oxyaen
Page 342:
Tulerpeton 14, 18 Tylopoda 264 Ukha
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