2 42 Nothosaurus M nster, 1834 ( ) Nothosaurus youngi sp. nov. ( 1 3) ( ) (, IVPP V 13590), ( 160mm) ;,, ; 5 4 ;, ; ; ;, ; 4 Nothosaurus, N. g

Transcription

1 VERTEBRATA PALASIATICA pp figs ) Nothosaurus 1 2 ( ) (2 IL ) : Nothosaurus youngi sp. nov.,,, N. youngi N. juvenilis N. youngi Nothosaurus,,, :, : Q : A : (2004) ( Keichou2 saurus hui Young, 1958) 1965 (Nothosauria, Simosauri2 dae, Shingyisaurus unexpectus) Rieppel (1998),,, ( Nothosaurus sp. ) Rieppel (2000) Nothosaurus, ( ), ( N. edingerae Schultze, 1970) Rieppel (2000) 8, N. mirabilis M nster, 1834, N. cymatosau2 roides Sanz, 1983, N. edingerae Schultze, 1970, N. giganteus M nster, 1834, N. haasi Rieppel et al., 1997, N. juvenilis Edinger, 1921, N. marchicus Koken, 1893 N. tchernovi Haas, (Muschelkalk) N. jagisteus Nothosaurus sp., 5 ( NGMC Vm 1308) 20 90, ) ( : ) :

2 2 42 Nothosaurus M nster, 1834 ( ) Nothosaurus youngi sp. nov. ( 1 3) ( ) (, IVPP V 13590), ( 160mm) ;,, ; 5 4 ;, ; ; ;, ; 4 Nothosaurus, N. giganteus, 4 (fangs) ; N. mirabilis 460mm,, ; N. tchernovi, ; V Nothosaurus, V : N. edingerae, ; N. juvanilis, ; N. haasi,, ; N. jagisteus,, 1Π3 2Π3 V Rudersdorf Karlstadt N. marchicus N. youngi N. marchicus, N. youngi, , , 1. 5 N. marchicus , (1. 6) ( Rieppel and Wild, 1996), N. marchicus, 5, N. youngi 4 ; N. marchicus 1Π2, N. youngi,, N. youngi, 1Π4-611, N. marchicus (Rieppel and Wild, 1996) N. youngi N. marchicus,, N. youngi, N. marchicus, N. youngi, N. youngi, Simosaurus (Rieppel, 1994),

3 1 : Nothosaurus 3

4 ( ) ( IVPP V 13590) Fig. 2 Skull and lower jaws of Nothosaurus youngi sp. nov. ( IVPP V 13590) in dorsal view Abbreviations :Ar. Articular ; At. Atlas ; Ax. Axis ; CV3. The 3 rd Cervical Verte2 bra 3 ; D. Dentary ; Eo. Exoccipital ; F. Frontal ; J. Jugal ; M. Maxilla ; N. Nasal ; Op. Opisthotic ; P. Parietal ; Pm. Premaxilla ; Po. Postorbital ; Pof. Postfrontal ; Prf. Prefrontal ; Q. Quadrate ; Sang. Surangular ; So. Supraoccipital ; Sq. Squamosal ( Lariosaurus xingyiensis) (,2002 ;Rieppel et al., 2003) Nothosau2 rus sp. (NGMC Vm 1308) ( Shingyisaurus unexpectus Young, 1965), 5 NGMC Vm 1308, Vm Π5, N. youngi ;, 1Π2 Nothosaurus

5 1 : Nothosaurus 5 3 ( ) ( IVPP V 13590) Fig. 3 Skull and lower jaws of Nothosaurus youngi sp. nov. ( IVPP V 13590) in ventral view Abbreviations : Ang. Angular ; Ar. Articular ; Ax. Axis ; Bo. Basioccipital ; C. Coronoid ; CV3. The 3 rd Cervical Vertebra 3 ; D. Dentary ; Ec. Ectopterygoid ; Hy. Hyobranchium ; M. Maxilla ; Pl. Palatine ; Pt. Pterygoid ; Q. Quad2 rate ; Sp. Splenial ; V. Vomer Lariosaurus (parietal skull table), Nothosaurus N. youngi, - : Lariosaurus xingyiensis 1Π3,, N. youngi, ;L. xingyiensis - N. youngi ; L. xing2 yiensis, N. youngi Rieppel (1999) 25, Pachypleurosauroidea Simosaurus 8

6 6 42 ( Winterswijk ), (TL = 62,CI = , RI = ) 2001 Rieppel 25 2, Nothosaurus jagisteus, 1999 ( TL = 65, CI = , RI = 01651), V Rieppel (2001) ( 3), PAUP Version 4. 0b10, Pachypleurosauroidea Simosaurus Germanosaurus, Branch2and2Bound, 12 ( 5) 7 ( 4) Rieppel (2001) 12 N. juvenilis Nothosaurus Nothosaurus ( 23 22) Rieppel (2001), 4 (1), 5 (1), 19 (1), 21 (1), 22 (2), 23 (2) 24 (1) N. juvenilis :10 (1) ;12 (1) ; 18 (1) Nothosaurus, N. gigantius, N. mirabilis, N. jagisteus ( N. haasi, N. tchernovi), N. edingerae, N. marchicus, Winterswijk N. juvenilis, N. edingerae N. youngi N. marchicus N. youngi Nothosaurus,, (,1958 ;,1985 ;,2002),,, A NEW NOTHOSAUR FROM MIDDL E TRIASSIC OF GUIZHOU, CHINA LI Jin2Ling 1 RIEPPEL Olivier 2 (1 Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences Beijing ) (2 The Field Museum Chicago IL , USA) Key words Xingyi, Guizhou, Middle Triassic, Nothosauridae According to Rieppel (2000), the genus Nothosaurus contains 8 valid species ( N. mirabilis, N. cymatosauroides, N. edingerae, N. haasi, N. giganteus, N. juvenilis, N. marchicus, N. tchernovi), which were all found in deposits ranging from the lower Anisian to the lower Carnian of the Western Tethyian faunal province ( Europe, northern Africa and western Asia). More recently, a new species, N. jagisteus, was described by Rieppel (2001) based on a partial skeleton from upper Muschelkalk of southern Germany.

7 1 : Nothosaurus 7 The first representative of the genus Nothosaurus in the Eastern Tethyian faunal province is Nothosaurus sp. ( Rieppel, 1998), represented by a seriously damaged skull and 5 cervical verte2 brae (National Geological Museum of China Vm 1308), and previously recognized as a simosaur Shingyisaurus unexpectus by Young C C in Since the 1990s, many nothosaur specimens have been discovered from the Zhuganpo Member of the Falang Formation in Xingyi, Guizhou and in ad2 jacent areas. The material described in the present paper was collected during the field season of Sauropterygia Owen, 1860 Nothosauria Seeley, 1882 Nothosauridae Baur, 1889 Nothosaurus M nster, 1834 Nothosaurus youngi sp. nov. (Figs. 1 3) Etymology Named in honor of the founder of Chinese vertebrate paleontology and the pioneer of Chinese Triassic marine reptile study, late Academician Chung2chien Young. Holotype A nearly complete skull, lower jaws and incomplete postcranial skeleton ( IVPP V 13590). Locality and horizon Xingyi, Guizhou ; Zhuganpo Member, Falang Formation, Middle Tri2 assic. Diagnosis A small sized species of Nothosaurus with skull condylobasal length 160mm ; 5 large procumbent fangs present on premaxilla and 4 curved fangs on mandibular symphysis ; jugal narrow and splint like with its anterior end excluded from orbit, and postorbital and maxilla in con2 tact behind jugal ; distinct and well developed ventrally projecting ectopterygoid flanges present ; lower jaw bearing an obvious coronoid process ; splenial entering the mandibular symphysis ; 4 carpal ossifications. Description The specimen IVPP V is exposed on its ventral side. It is an incomplete skeleton, with the palatal surface of skull, manus, pes and gastralia broken, the left anterior limb lost, and the dorsal vertebrae and ribs embedded in matrix. The skull was flattened during fossiliza2 tion, but its dorsal surface is perfectly preserved. The skull is similar to that of Nothosaurus marchi2 cus in contour and size. The snout is short and blunt, with a weakly developed rostral constriction. Both the external naris and orbit are short and wide. The elongate upper temporal fenestra is con2 stricted at the anterior corner. Its longitudinal dimension is uwo times as that of the orbit. The ratio of skull length to width (divide the distance of anterior end of snout2occipital condyle by skull width at postorbital) is 2. 75, smaller than the corresponding ratio in N. mirabilis ( ) and in N. giganteus (3. 32) (measurements from Rieppel and Wild, 1996, Fig. 58 and Fig. 10). The premaxilla forming the rostrum contacts the maxilla at the anterolateral corner of the exter2 nal naris. The posterior process of the premaxilla extends backward between the external nares to meet the nasal at the level of the posterior end of the external naris. Its surface is sculptured with small and scattered pits. Five premaxillary fangs are variously preserved on left and right side. The 1 st right premaxillary tooth is lost, represented by a large alveolus. The 3 rd is the stoutest fang and the 4 th and 5 th are reduced successively in size on the right side. The 1 st, 3 rd and 5 th fangs are com2 paratively small, but the 2 nd is large and the 4 th is the strongest on the left side. The nasal is a large and leaf2shaped element. It meets its counterpart along the midline, sepa2 rating the premaxilla from the frontal. A short and slender anterior process of the nasal extends for2 ward to the middle point of the medial margin of the external naris as is also the case in N. haasi, in contrast to the processes reaching to the anterior end of the external naris in N. juvenilis, N. giganteus and N. mirabilis. The nasal contacts the maxilla, prefrontal and frontal laterally. The surface of the bone is decorated with a distinct radiating pattern of grooves and ridges.

8 8 42 The frontal is fused. Its anterolateral corner is separated from the maxilla by a contact of the nasal and prefrontal as in N. juvenilis, whereas, in N. marchicus and N. jagisteus the frontal contacts the maxilla. The lateral margin of the frontal is comparatively straight, a short distance of which enters the medial border of the orbit. The frontal extends posteriorly to meet the parietal in an interdigitating suture well behind the anterior end of the upper temporal fossa. There are many deep longitudinal grooves and ridges on the frontal. The prefrontal is a small bone located between the maxilla, nasal and frontal. It occupies the anteromedial border of the orbit. The sculpturing of the surface of the bone is deep and stout. The postfrontal defines the posteromedial border of the orbit, with a distinct postorbital con2 striction, and its posteriorly pointing apex is embraced between the postorbital and the parietal. The posterior end of the postfrontal reaches to a point behind the anterior end of the upper temporal fos2 sa, but does not enter the margin of the fossa. The parietal is elongate and unpaired. An elongated pineal foramen is located in a trough near the posterior end of the parietal. Before the pineal foramen the parietal narrows to a slender skull ta2 ble, whereas a sagittal crest is behind the pineal foramen in N. edingerae. Posteriorly, the parietal is broadened, with a concave posterior margin. A well defined occipital crest separates the parietal skull table from the occipital exposure of the parietal. The maxilla forms a significant part of the lateral margins of the external naries and the orbit, extending posteriorly from the antero2lateral corner of the external naris to a level behind the anterior end, but in front of 1Π4 length of the upper temporal fossa. As in N. marchicus, N. juvenilis, N. giganteus and N. mirabilis there is a small depression on the maxilla lateral to the external naris, and a small foramen is present on the floor of the depression. The right maxillary dentition is almost completely preserved. One basal part of a crown with a large cross section, represents the first max2 illary fang that is retained on the laterally buldging part of the maxilla between the external naris and the orbit. Following that a large alveolus indicates the presence of the second maxillary fang. There are 4 positions for smaller teeth (only the 3 rd is preserved) in front of the fangs, but 16 (11 teeth preserved) behind the fangs. The large postorbital forms part of the posterior margin of the orbit, and the anterior margin of the upper temporal fossa, with a posteromedial branch that is shorter than the posterolateral one, the latter reaching almost to the middle point of the upper temporal fossa. The postorbital arch formed by the postorbital is relatively narrower than that of other species of Nothosaurus. The distance orbit2 external naris ( 15mm) divided by the distance orbit2upper temporal fossa ( 7mm) is 2.14, but around 1 in N. marchicus. The jugal is a small and strap2shaped bone, located between the maxilla and postorbital. Its anterior end does not enter the margin of the orbit, and its posterior end seems to be embraced by the postorbital and the maxilla as in N. jagisteus, which shows only on the lateral view of the skull. The squamosal is a triradiate element, with its anterior ramus contacting the postorbital at the mid2point of the temporal arch and the maxilla at a level anterior to 1Π4 length of the upper temporal fossa. Posterolateral to the upper temporal fossa, the squamosal is drawn out into a distinct and long lateral ramus, which covers the upper end of the quadrate. On the occipital surface the squamosal meets the supraoccipital and the opisthotic. The right quadrate is slightly broken, while the left one is completely preserved. The bone has a wide connection with the quadrate ramus of the pterygoid on the ventral view. The lateral condyle of the quadrate is larger than the medial one. They are situated in different horizontal and vertical levels the lateral condyle is higher and anteriorer than the medial one. The occiput is closed and plate like, but no posttemporal foramen and opening of cranioquad2 rate passage can be detected (perhaps due to dorsoventral compression of the skull). Because some anterior cervical vertebrae overlap the lower part of the occiput, the occipital condyle is only exposed on the ventral surface. It is located at the same level as the mandibular condyles of the quadrate.

9 1 : Nothosaurus 9 The supraoccipital is a leave2shaped element that carries a distinct sagittal crest, which does not reach the anterior margin of the bone. The foramen magnum is obscured by the dislocated exoccipi2 tals. The opisthotic is large, and its lateral margin seems not contact the quadrate. The major features of the palate can be established, although some bones are crushed and its anterior portion is covered by the symphysis of articulated lower jaws. The exact shape of the vomer is difficult to determine, because it was deformed by some longitudinal grooves. But it does show evidence of forming the medial margin of the choana and contact the palatine laterally and the ptery2 goid posteriorly. The palatine is a quite large, thin bone that forms the posterior margin of the choa2 na, which is located further posteriorly relative to the posterior margin of the external naris than is the case in N. haasi and N. marchicus. A long narrow portion of the maxilla is exposed on the palate lateral to the palatine. The distinct ectopterygoid flanges are preserved on both sides, forming triangular projection with its medial apex pointing posteromedially and sharply turned downward. The posterior portion of the pterygoids including left and right quadrate rami, are well preserved. Two el2 ements of the hyobranchial skeleton are preserved, the right one is located on the ventral surface of the pterygoid, and the left one near the left ectopterygoid flange. The lower jaw is elongate and slender. Correlated with the short premaxillary rostrum, the mandibular symphysis is short and broad, with its ratio of length to width 0. 96, much smaller than in N. jagisteus. The mandibular symphysis bears 4 enlarged fangs, which are curved up2 wards, instead of being procumbent. The 1 st, 2 nd and 4 th left dentary fangs are of approximately equal size, but the 4 th fang has a slightly more sturdy tooth base. A small tooth is just erupting from the 3 rd alveolus. On the right side the 1 st fang is lost, the 3 rd is the most slender, and the 4 th the strongest. The dentary is narrow and long, extending along 69 % of the length of the lower jaw. Be2 cause of the tight contact of the lower jaw with skull, the dentary dentition remains obscure. But it is possible to ascertain that the dentary tooth row extends a little further posteriorly than the maxillary tooth row. The coronoid is a rather small bone located on the medial side of the jaw. It differs from all other species of Nothosaurus in forming a distinct coronoid process. The anterior end of the sple2 nial appears to enter the mandibular symphysis. The jaw articulation is formed by the suprangular in its lateral part, and by the articular in its medial part. The retroarticular process is elongate. Measurements See Table 1. 1 ( ) ( IVPP V 13590) Table 1 Measurements of skull and lower ja w of Nothosaurus youngi sp. nov. ( IVPP V 13590) ( - ) skull length from anterior end of snout to occipital condyle length from anterior end of snout to anterior margin of external naris 29 - length from anterior end of snout to anterior margin of orbit 55 - length from anterior end of snout to anterior margin of supratemporal fenestra 87 - length from posterior margin of external naris to anterior margin of orbit 15 - length from posterior margin of orbit to anterior margin of supratemporal fenestra 7 - length from posterior margin of orbit to posterior end of skull 71 ( ) width of skull at the level of maxillary fangs 42 ( ) width of skull at the level of postorbital region 58 ( ) width of skull at the level of squamosal 81 ( ) size of external naris (length width) 11 7 ( ) size of orbit (length width) ( ) size of supratemporal fenestra (length width) length of mandibular ramus 186 length of mandibular symphysis 24 width of mandibular symphysis 25 (mm)

10 10 42 The postcranial skeleton is incompletely preserved. Within the vertebral column, the cervical and caudal vertebrae are preserved in articulation, two anterior dorsal vertebtae are exposed in later2 al view, the other dorsal and the sacral vertebrae are obscured by overlapping elements and matrix. Two small triangular elements which meet each other along the midline represent the neural arch of the atlas, which are directly overlapping the anterior part of the 3 rd cervical vertebra (Fig. 1). The neural arch of the axis is preserved in isolation lateral to the vertebral column, but the centrum of the axis can not be identified. The 3 rd 20 th cervical vertebrae expose their ventral surfaces, which are flattened, longer than wide, without lateral constriction, and without a distinct ventral ridge. The centra are platycoelous with a transversely widened elliptic contour as indicated by the 4 th and 5 th cervical centra. There is a short rib present on the 18 th cervical vertebra, showing a stout proximal end and tapering gradually distally. Two articular facets are present separately on the neural arch and the centrum of the 19 th cervical, indicating that the ribs of the posterior cervical vertebrae are double2headed. The sacral vertebrae cannot be seen in the specimen IVPP V 13590, whereas two left sacral ribs are exposed as fairly prominent elements. They are relatively long elements (35mm), with a narrow proximal end and widened distal end (15mm 8mm). 37 caudal vertebrae are preserved, exposed mostly in right lateral view. The caudal centra have no ventral sagittal ridge nor are they laterally constricted. The ribs on the anterior portion of the tail are relatively long, expanded in their middle region and tapering towards their distal ends. Many V2shaped and slender, rod2like gastralia are preserved, scattered in the region between the pectoral and pelvic girdles. The pectoral girdle in V is in general similar to that of Nothosaurus ( Romer, 1956 fig. 148A), but differs from the latter in some details. For example, the triangular interclavicle is relatively large, with its posterior border (36mm) longer then 1Π2 of the anterior edge of the clavicle (70mm). The posterior stem of the interclavicle is absent, but it is difficult to ascertain whether it is lost or absent originally. Only the flattened ventral surfaces of the lower part of both scapulae are exposed. The left coracoid is similar to that of other Nothosaurus species ( Romer, 1956 fig. 148A) in general shape, but it cannot be described because it is overlapped by some gastralia. Among the pelvic girdle two ilia and the right pubis are preserved. The ilium is small and low, but the pubis is a large plate2like element, with a concave anterior margin, a relative straight posterior margin, and a distinct obturator foramen. The left anterior limb is preserved incompletely the distal portion of the humerus is covered by gastralia and some phalangeals are lost. The humerus has a stout proximal end and a relative nar2 row diaphysis. The complete ulna and radius positioned originally resemble that of other Nothosau2 rus. The specimen V is different from other Nothosaurus species in having 4, rather than 3 elements in carpal region, which are intermedium, ulnare and two distal carpals. Comparison and discussion The specimen V from the Zhuganpo Member of the Falang Formation of Xingyi, Guizhou is more similar to that of Nothosaurus marchicus than to other species of Nothosaurus in size, shape and proportions of skull. Both of them are small sized animal, with skull condylobasal length 160mm in V and less than 200mm in N. marchicus. Their skulls show relatively short and broad rostrum with rounded contours and a distinct rostral constric2 tion. The skull ratios of V fit into the ranges of N. marchicus completely, as shown in Table 2. In addition, V shares a number of important characters with N. marchicus, such as na2 sals broad and leaf shaped, with radiating ornamentation, postfrontal with a distinct postorbital con2 striction, squamsal closely approaching the posterior end of the jugal, and so on. They distinguish each other in some respects. In V there are 4 small maxillary teeth in front of the maxillary fangs, rather than 5 as in N. marchicus. The ectopterygoid in V is general nothosaur shaped, but it tapers to a blunt tip anteriorly and reaches to about the level of the mid point of the palatine in N. marchicus. The specimen of V is different from all other species of Nothosau2

11 1 : Nothosaurus 11 rus in having a distinct coronoid process and a splenial entering the mandibular symphysis region. 2 N. marchicus Table 2 Skull proportions in N. youngi and N. marchicus N. youngi N. marchicus 3 - Π snout2external naris Πrostral constriction Π - snout2orbit Πsnout2external naris Π - snout2upper temporal fossa Πsnout2external naris Π longitudinal diameter Πtransverse diameter of external naris (1. 6) 3 from Rieppel et al., 1999 Table 1. Two other nothosaur taxa2nothosaurus sp. ( Young, 1965 ; Rieppel, 1998) and Lariosaurus xingyiensis (Li et al., 2002) were also reported from Zhuganpo Member of the Falang Formation, Xingyi, Guizhou. The poorly preserved specimen of Nothosaurus sp. (NGMC Vm 1308) is different from V in having a wider postorbital arch and a more posteriorly positioned frontal2parietal su2 ture. Although Lariosaurus xingyiensis has a typical lariosaur postcranial skeleton, but more notho2 saur2like skull, it is distinguished from V in having a nasal excluded from the medial margin of the external naris, and a saggital crest behind the pineal foramen. A data matrix including 25 characters of 11 taxa ( Pachypleurosaurs, Simosaurus, Germano2 saurus and 8 species of Nothosaurus) was analyzed cladisticly using the software package PAUP Ver2 sion , and one single most parsimonious tree with a TL of 62 steps, CI of , and RI of was obtained ( Rieppel et al., 1999). When a new species of Nothosaurus ( N. jagisteus) was included and two characters were modified in the cladistic analysis, one most pasimonious tree with TL of 65 steps, CI of , and RI of was yielded (Rieppel, 2001). The monophyly of the genus of Nothosaurus was well founded by the analyses, but as pointed out by Rieppel (2001), there also continues to be a poor match of the hierarchy of nothosaurs to the stratigraphical distribution of the species of Nothosaurus. 4 7 Fig. 4 The 7 th most parsimonious tree 5 12 Fig. 5 The strict consensus tree This time the data matrix ( Rieppel, 2001 Appendix I) adding the characters of N. youngi ( Table 3) is analyzed cladistically using PAUP Version 4. 0b10. All multistate characters were treated as unordered and equally weighted, with pachypleurosaurs, Simosaurus and Germanosaurus as outgroups. Branch2and2bound search, ACCTRAN optimization yields 12 most parsimonious trees. The hierarchy of the taxa in the 7 th tree is (pachypleurosaurs ( Simosaurus ( Germanosaurus ( N. ju2 venilis ( N. youngi (Winterswijk ( N. marchicus ( N. edingerae ( N. giganteus ( ( N. mirabilis, N. jagisteus) ( N. haasi, N. tchernovi) ) ) ) ) ) ) ) ) (Fig. 4). The clade of the monophiletic genus

12 12 42 Nothosaurus is supported by 4 (1), 5 (1), 19 (1), 21 (1), 22 (2), 23 (2), 24 (1), same as that in the tree obtained by Rieppel in The synapomorphies for the clade ( N. youngi (Winterswijk ( N. marchicus ( N. edingerae ( N. giganteus ( ( N. mirabilis, N. jagisteus) ( N. haasi, N. tchernovi) ) ) ) ) ) are as follows : postfrontal remains excluded from upper temporal fossa 10 (1), postorbital forms all anterior margin of the upper temporal fossa 12(1), anterior corner of upper tem2 poral fossa constricted by distinct lateral convexity of parietal 18(1). In the strict consensus tree of 12 most parsimonious trees (Fig. 5), the relationship of ( N. giganteus, N. mirabilis, ( N. haa2 si, N. tchernovi), N. jagisteus), and the relationship of ( N. edingerae, ( N. giganteus, N. mirabilis, ( N. haasi, N. tchernovi), N. jagisteus), N. marchicus, Winterswijk) remain un2 solved. The phylogenetic analysis proves that N. youngi as an independent species is more primi2 tive than all species of Nothosaurus but N. juvenilis. 3 ( ) ( Rieppel, 2001 Table 7 and appendix 1) Table 3 Characters of Nothosaurus youngi sp. nov. (Data matrix and character analysis same as Table 7 and appendix 1 of Rieppel, 2001) 1(1) 2 (1) 3 (0) 4 (1) 5 (1) 6 (?) 7 (1) 8 (1) 9 (1) 10(1) 11(0) 12(1) 13(0) 14(1) 15(0) 16(1) 17(0) 18(1) 19(1) 20(1) 21(1) 22(2) 23(2) 24(1) 25(?) References Chen Z F ( ), Stratigraphical position of Keichousaurus hui Young of Middle Triassic and its significance in southwest2 ern Guizhou. Geol Guizhou( ), 5 : (in Chinese) Edinger T, Βber Nothosaurus. II Zur Gaumenfrage. Senckenbergiana, 3 : Haas G, Ein Nothosaurier2Schgdel aus dem Muschelkalk des Wadi Ramon (Negev, Israel). Ann Naturhist Mus Wien, 83 : Koken E, Beitr ge zur Kenntnis der Gattung Nothosaurus. Z deutsch geol Ges, 45 : Li J L ( ), Liu J ( ), O Rieppel, A new species of Lariosaurus (Sauropterygia : Nothosauridae) from Triassic of Guizhou, southwest China. Vert PalAsiat ( ), 40(2) : (in Chinese with English summary) M nster G, Vorlgufige Nachricht ber einige neue Reptilien im Muschelkalke von Baiern. Neues Jahrb Mineral, Geognosie, Geol Petrefaktenkunde, Rieppel O, Osteology of Simosaurus gaillardoti and the relationships of stem2group Sauropterygia. Fieldiana Geol, n s, 28 : 1 85 Rieppel O, The status of Shingyisaurus unexpectus from the Middle Triassic of Kweichou, China. J Vert Paleont, 18 (3) : Rieppel O, Sauropterygia I. In : Wellnhofer P ed. Encyclopedia Paleoherpetology, part 12A. M nchen : Verlag Dr. Friedrich Pfeil Rieppel O, A new species of Nothosaurus (Reptilia : Sauropterygia) from the Upper Muschelkalk (Lower Ladinian) of south2 western Germany. Palaeontographica Abt A, 263 : Rieppel O, Li J L, Liu J, Larriosaurus xingyiensis (Reptilia : Sauropterygia) from the Triassic of China. Can J Earth Sci, 40 : Rieppel O, Mazin J2M, Tchernov E, Speciation along rifting continental margins : a new nothosaur from the Negev ( Israel). Comptes Rendus de l Acad mie des Sciences, Paris, 325 : Rieppel O, Mazin J2M, Tchernov E, Sauropterygia from the Middle Triassic of Makhtesh Ramon, Negev, Israel. Fieldiana Geol, n s, 40 : 1 85 Rieppel O, Wild R, A revision of the genus Nothosaurus (Reptilia :Sauropterygia) from the Germanic Triassic, with comments on the status of Conchiosaurus clavatus. Fieldiana Geol, n s, 34 : 1 82 Romer A S, Osteology of the reptiles. Chicago &London : The University of Chicago Press Sanz J L, Los Nothosaurios (Reptilia, Sauropterygia) Espanoles. Estud geol (Madrid), 39 : Schultze H2P, Βber Nothosaurus. Neubeschreibung eines Schgdels aus dem Keuper. Senckenbergiana lethaea, 51 : Young C C( ), On the new Pachypleurosauroidea from Keichow, southwest China. Vert PalAsiat ( ), 2 (2 3) : Young C C( ), On the new nothosaurs from Hupeh and Keichou, China. Vert PalAsiat ( ), 9 (4) :