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Zeitschrift/Journal: Zitteliana - Abhandlungen der Bayerischen Staatssammlung für Paläontologie und Histor. Geologie

Jahr/Year: 2002

Band/Volume: 23

Autor(en)/Author(s): Immel Harald, Guoxiong He

Artikel/Article: of the Tethyan Himalaya of southern Tibet 79-105 © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at

Zitteliuna 23 79-105 Í1RS., 4 p]s. München, 15.12.2002 ISSN 0373-9627

Cretaceous cephalopods of the Tethyan Himalaya of southern Tibet

Von HARALD LMMLL & HE GUOXIONG

ABSTRACT

Following .i short review of the regional and stratigraphic In conclusion some palaeobiogeographic aspects are distribution ot Cretaceous cephalopods (Neocomian - discussed. The ammonite fauna ot the Middle Cretaceous Maastrichtian, especially Aptian to Cenomanian) from the shows some influence from the southern temperate realm but Tethvan Himalaya of southern Tibet 29 taxa are described, indicates a closer relationship to the hoplitimd faunal province including three new species: Plcinobophtcs (Pleurohoplitcs) of the northern temperate (boreal) realm. This suggests that robusticostatm, Lemuroceras tibcticum, and Tnnobduntcs during the Middle Cretaceous the Tethvan Himalaya of multitubercuLitus. southern Tibet might have occupied a geographic position larther to the north, with an open marine connection to the south.

KURZFASSUNG

Ausgehend von der regionalen und stratigraphischen Ver­ Abschließend werden einige pnl.iobiogeogrnphische Zusam­ breitung kret.r/ischer Cephalopoden (Neokom - Maastricht) menhänge diskutiert. Die mittelkretazische Ammonitenfauna des Tethvs-Himalaya von Siidtibet werden 29 Gattungen und zeigt neben Einflüssen aus dem südlichen gemäßigten Bereich Arten beschrieben, vor allem aus dem Apt - Ccnoinan. Dabei vor allem enge Beziehungen zur Hophten-Provinz des nörd­ werden drei neue Arten aufgestellt: Plenroboplites (Pleuro- lichen gemäßigten (borealen) Raumes. Insofern muß für den bophtes) robusticostatus, Lemurocenis tibeticum und Tono- Tethvs-Himalaya Südtibets zur Zeit der mittleren Kreide eine bamitcs multitubercuLitus. paläogeographische Position weiter im Norden angenommen werden, allerdings auch eine offene Verbindung nach Süden.

1. INTRODUCTION

An ammonite fauna from two localities in southern Tibet is AC KNOWl EDGE MENTS described. Field work was carried out in 1983 and 19S6, and We thank the Academia Sinica and the Max-Planck-Gesellschalt preliminary results have been discussed at the Third Meeting for financial support of this project as well as the Chinese and German of the European Union of Geosciences (EL'G 111) at Strasbourg colleagues for preparing and carrying out the expeditions to Tibet in in April 1985 (see Fit & Immli. 19S5). For several reasons the 19S3 and 1986. paper could not be published earlier, although other studies have been, for example on lithostratigraphv (e.g.W ili fms & Thanks also to E. Schmifja (preparation), F. H ofck. (photos) and Zang 1993), bio- and ichnofacies (Zhou et al. 1997), the bivalve k. Dossow (drawings), and last not least to Dr. P. Wellnhofer and fauna (Wf.n 2000), and also the palaeomagnetic results (e.g. Dr. M. Musik for some corrections of English language and Dr. M. Patzelt et al. 1996). Mom k also for help with the computer.

Prof. Dr. H arm n Immei., Department fur Geo- und Umweltwissenschatten der Ludwig-Maximilians-Universitat München - Section Paläontologie und Historische Geologie, Richard-Wagner-Str. 10/lf, D-80333 München/Deutschland. Prof. Dr. Ht Guoxionc ,, Nanjing Institute of Geologe' and Palaeontology, Academia Sinica, C.hi-Ming-Ssu, N.inpng 21000S/P. R. China. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at KO 2. LOCALITIES AND STRATIGRAPHY

Previous works: The first Cretaceous cephalopods Id e n tifie d a m m o n ite s: A precise generic or specific (ammonites only) of southern Tibet - espeeiallv Irom the assignment is not possible. Most ammonoids belong to the Gamba region - were announced hv Oouvn 11- (1916) who subfamily Neocomitinae but a few fragments could also be described and figured the ainmonoids sampletl hv the British assigned to the family f Iaplocei atidae, probably to expedition to Tibet in 1903. The stratigraphic data have been Ncohisoccrds Spath , 1923. published In H m til N (1907). In modern terms all am monoids Age: lower Lower Cretaceous. originate Irom parts of the Gamba Group (see the correlation in \Yl N 1987: 144). The updated systematic and stratigraphic results of D ouviut (|9|6) are presented in lig. I. A second suite of Cretaceous ammonites was collected by the Chinese Section A Scientific Mxpedition to the Mount Jolmo Lungma region f'his section is by far the most important one, not onlv with (1966-1968) described and figured by ZllAO (1976). Beside respect to its duration but also to the ammonites of the Gamba these two papers onlv a tew notes or lists of Cretaceous Group. The great number of samples will be summarized in ammonites exist but without any description or figures, for I I ammonite 'levels' (figured representatives are indicated with example in Ml et al. (1973: 107ft.). A recent listing of sample numbers in brackets. The same applies to the following ammonoids from the Gamba Group in southern Tibet is given sections). hv W i n (1987: I 33ft.) who named also some ammonoids from the Cretaceous of the more northern Gvang/e area (op. at.: I d e n t i f i e d a m m o n i t e s: I 48f f.). f rom the younger Zongshan formation no (top) cephalopods are reported except a short mention inW an level 11: Hvsteroccnis semdeve (e.g. Al 84/1, see pi. 1, tig. 5) (1988: 1 14, tab. 3). Mortomccras (}Mort(»uier,is) sp. N ew re su lts: The new cephalopods described below undeterminable Anisocer.itidae originate from two areas in southern Tibet: Gamba and I )uela. level 10: ,UortomcerdS (Mortoiuceras) sp. I'he topographic and geologic position of the two localities Gooilhdllttcs cl. gracillimum (e.g. At 150/1, see pi. 3, are shown m fig. 2. ft follows a short overview of the % 7) level 9: C y;ndljophtcs sp. (Af 76A/2, we pi. I, fig. 4) fauna as far as it was determinable, with its stratigraphic and tectonic implications. Doiivillcucrdi sp. level 8: Doiivillcucidipustulosum (e.g. At 73A/I, see pi. 4, fig. 7) level 7: Hchcducylus sp. (Al 71/6, see pi. 4, tig. 5) 2.1 GAMBA ARb.A Toxoccrdtuidcs aft. roycrumum (At 71 /7, see pi. 4, fig. 6) In the Gamba area cephalopods have been found in eight Ti»inbd»iitci miiltituberciildtns (Af 71/8 and At 71/5, see pi. 4, tig. 3, 4) sections, respectively sampling points, tug. 3 schematically shows seven of them yielding ammonites with their geographic ( 'hcloimcrds (( '¡jcloniccrds) aft. biixturfi (e.g. Af 71 /I , position and age. see pi. 4, fig. 8) C olnm lm crdi (C blombicerds) cf. subpcltuccroidcs (e.g. Af 71/4, see pi. 4, fig. 2) Section K Pdrdboplita trautichohli (e.g. Al 71/10 and Af 71/1 I, Several dozen fragments of specimens of ammonoids have see pi. 4, tig. 1 I, 12) been found. All are extremely broken, crushed and badly level 6: AcuncccrdS ( \cn n cco \n sp. ) (At 65/1, see pi. I, fig. 3) preserved. Cbcloniccrds (( belomceras) sp.

Ce noman is n Original determination Modern nomenclature L M U

Acanthoceras Newboldi Calycoceras (Newboldiceras ) (p .3 ;p i . 1 , f i g . 1 , 2 , 3 , 4 ) n e w b o ld i Mantelhceras laticlavium Sbarpeiceras laticlavium (p.4 ; p l . 1 , f i g . 5 ;pl.2,fig.1-2) Mantelliceras discoidale Acanthoceras discoidale ip .4 ; p l . 3 , f i g . 1 ) I

(p .5 ,-p i . 3 , f i g . 3 ) Turrilites Wiestii Turrilites acutus (p .5 ; p l . 3 , f i g . 2 ) Turrilites Desnoyersi Turrilites scheuchzerianus (p .6 ; p l . 3 , f i g . 4 - 5 )

lug. I: Arnmoniies described and figured from the Gamba Group of southern Libel bv 11. D ow n11 I I9IM and their names in modern nomenclature. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 81

Tsdidam Basin

I All Alluvial plain G 3 Molas se type sediments Tethyan sediments Thrusts and suture.- I *~'\ C ry sta llin e of High Himalaya AT Astin Tagh run Le sser Himalaya NS Northern Suture HK Hindukush O phiolites i n c i . o p h io litic melanges MFT Main Frontal Thrust Ju Jungbwa nappe and related pelagic sediments MBT Main Boundary Thrust K3 Kangchenjunga MCT Main Central Thrust Ks Kailas KSv*! Tertiary and Quaternary volcamcs ITS Indus Tsangp. Suture NB Namche Barwa BS Banggong Suture NP Nanga Parbat n n Transhimalayan plutons JS Jinsha Suture Cl Qomolangma 'JlZ. Matn thrust and fault zones CS Chilien Suture Sp Spongtang Klippe ûuO 400 Km a _I_____i

Paleocene, Eocene r " " j Permo- main limestone & shales limestone & elastics S highway Cretaceous shelf i\ \ | - CJIÍT- G>'ron8" \m limest & elastics h—s—J slate, marble, etc Kangmar thrust shelfal Precambnan TOT Tingri-northem carbonate & elastics crystalline Gamba thrust

Fig. 2 a: Simplified genlogic.il map ot Tibet and tile 1 liinl.iyas (modified after G w s s ir IUS3: tig. 3) 2 h: geological map of the investigation area with the location nt the sections A and V (alter P \r/i 11 el al. 19%: fig. lb). For the location ot all other sections and sampling points ot the Gamba area see lig. V © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 82 Section I This section was not measured, so it is regarded here as a single sampling point.

1 d e n t i I i e d a m m on ites: ( \illibophtcs cl. tetragonus Plcurobophtcs (Plcurobophtcs) robusticostatus (ft 1/1 and If 1/3, see pi. 1, fig. 8,')) Proturnhtoulcs sp. (If 2/1, see pi. 4, tig. 13) Age: Middle - Upper Albian.

Section H This section was not measured, so it is regarded here as a single sampling point. Identified a m m onites: ( '.alliboplitcs sp. Plcurobophtcs (Plcurobophtcs) sp. Age: Upper Albian.

Section G Several meters above the measured section some isolated ammonites have been found. Identified am m onites: Mortoniccras (Durnovantcs) hiliam (Gf 16/1, see pi. 3, fig. 1) Mantclliccras sp. Age: Upper Albian - Lower Cenomanian.

Section B There are three horizons from which ammonites have been determined. identified ammonites: (top) Eucalycoceras colhgnom (e.g. Bt 74/1, see pi. 3, tig. 3) Fig. 3: Topographic imp oi tin Gamha .lies with the location ot the Mantclhceras cf. m antclh (Bt 35/1, see pi. 3, fig. 6) sections ami sampling points. The stratigraphic ages are that provided Mantclhceras lymensc (Bt. 31/1, see pi. 3, tig. 5) by the ammonite fauna. Nearly all ammonites are from the Gamba Group, with only tew exceptions, which arc from the younger (bottom) Zongshan borntation. Age: Lower and Upper Cenomanian.

Section C A level 5: Calliboplitcs tetragonus The two ammonites out of one horizon of this section are level 4: Culhhophtcs tctraganits the only ones found in the Zongshan Formation. Culhhophtcs ci.glossonotus (e.g. At 39/1, see pi. 1, tig. 7) level 3: ( alhhophtes tetragonus (e.g. At 172/1, see pi. I, fig. 6) Identified a m m onite: level 2: Lcmuroccras tibeticum (At 18/1, see pi. I, tig. 10) Submortonncms tcniucosUiLitum (e.g. ( *\l 74/1, see pi. 4, tig. 1) level 1: Lonuroicrcts tibcticum (At 184/1, see pi. 1, tig. 1 1) Age: Middle Campanian. (bottom)

Age: t he stratigraphic position ol these ammonite horizons Section D is given in tig. 4. They range, including some gaps, from the Two nautihds originate from this section. Upper Aptian to the uppermost Albian. However, there is Id en tified e e p h a 1 o p o d : clearly a thrust between level 5 and 6 where the stratigraphic Pscudoccnoccras alt. largiUicrtninum (e.g. l)f 147/1, see pi. I, age is shifted back by one stage. Also ionic imbrication structures are likely, tor example between levels 1 and 2 and f'g- 0 also between levels 8 and 4. Age: Maastriehtian according to henthonic toraminifera. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at S3

limestone, sandstone, partly marly or sandy fine- to coarse-grained calcareous marl, claystone, partly arenaceous partly silty

marlstone, thrust partly arenaceous

Fig. 4: Section A (Gamba area, for location see figure 2 and 3) with eleven ammonite 'levels', their stratigraphic age and tectonic implication (the sample numbers correspond with those bvW illems & Zhano !443 fig 3). The Gamba Group is divided into three formations. In ascending order these are the Ganbadongshan Formation (Fm. I/, the Chaquiela Formation (Fm. II) and the Ganbacunkou Formation (Fill. Ill) (see Zhou et al. 1997: 5, lor different spelling see Wen 2000: 2). © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 84

In hi;. 5 the ammonite taxn o) the Gamba Group and their Identified eephalopods: stratigraphic ayes are summarized. Comparison with pres io us ( ynidtoicrdi kdvisinbj (\'f 16/2, see pi. 1, tiy. 2) studies (see espeeiallv tiy. 1) shows a wider svstematie and Mortoimerds (Mortmmerds) intermedium (Vf 17/1, see pi. 2, stratigraphic speetrum, hut also a poor doeumentation tor the by. 4) Cenomanian. In part, howeser, this eotild lie due to the fnet Mortoimcitn ( Mortonueras) pnea (Vf 15/1, see pi. 2, fiy. 2) that some material, espccialls a small eolleetion of turnlitids, MorttnmerdS (Mnrtmmerdi) roitrdtum (e.y. Vf 16/1, see pi. 2, got lost at the transport from Nan|iny to Munich. by. 3) Mmtoniicr.ii (Dciradoicrai) impmoutm (Vt 16/3, see pi. 2, tiy. I) Murtoimerdi (Dendduierus) devoueme (e.y. Vf 17/3, see pi. 3, 2.2 DU I LA ARLA by. 4) (inodbdllitei prmcntm (Vf 17/2, see pi. 3, by. 2) In the onl\ measured seetion at the Zala valley of Duela area (Seetion V) all eephalopods onymate from the lower part, ft should be noted that all ammonites belong to the subfamily from a senes of thick las ers of limestone, with a total thickness Mortonieeratinae which is rare in the Gamba area, indicating of three and a halt meters. This series is composed of a that this subfamily preferred a calcareous facies rather than calcareous facies within the Gambia Group that can not be the mud-dominated si lie ¡elastic facies of the typical Gamba compared dircctls with ans sequence of the (Samba Group at Group. the tvpe locality. Aye: Upper Album.

Aptian Albian Cenomanian Ammonites (Gamba Group) L U L M U L M U

Aconeceras (Aconeceras) sp. Cymahoplites sp. Lemuroceras tibeticum n.sp. Pleurohoplites (Pleurohoplites) robusticostatus n. sp. Callihoplites tetragonus Callihoplites cf. glossonotus Hysteroceras semileve Mortoniceras (Mortonlceras) intermedium Mortoniceras (Mortoniceras) pricei Mortoniceras (Mortoniceras) rostratum Mortoniceras (Deiradoceras) bispinosum Mortoniceras (Deiradoceras) devonense Mortoniceras (Durnovarites) kiliani Goodhallites procerum Goodhallites cf. gracillimum Mantelliceras cf. mantelli Mantelliceras lymense Eucalycoceras collignoni Toxoceratoides a ff. royerianum Tonohamites multituberculatus n.sp. Helicancylus sp. Proturrilitoides sp. Cheloniceras (Cheloniceras) a ff. buxtorfi Douvilleiceras pustulosum Colombiceras (Colombiceras) c f. subpeltoceroides Parahoplites trautscholdi

I ly 5; flic .mi i in mites nl the ( i.imh.i ( u imp .11 < i.mih.i anil 1 tucla area and then stratiyi apluc distribution. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at S3 3. SYSTEMATIC DESCRIPTION

The classification ot the ammonoids follows the outline of ( 'rimea and also from the upper ( .rcteceous of Libya and the W kioiit (1996) in Part L of the Treatise on Invertebrate southern USA. According to Wll DM ANN N Si uni hier (1 979: Paleontology ( 4, rc\ ised: Cretaceous AnunonoiJea). 654) /’. Lxrgilhcrtnuuim is a species of the Westeuropean All originals are provisionally deposited in the collection of Cenomanian, but since then it has been reported also from the Ba\ erische Staatssainmlung für Paläontologie und Geolo­ New Mexico (C obban N K in n m ii 1994). Lire isolated gie in Munich. fragments ot the Gamba area have been sampled in sediments The measurements of specimens are given m millimeters. of Maastrichtian age. The ahbrev iations are as follows: D _ diameter Family Gy matoceratidae Spai 11, 1927 V h = whorl height Genus Cymatocents I h \l l, 1884 Wjb = whorl breadth Wh/Wb = ratio of whorl height to whorl breadth Type species: Cymdtoccfdi pscudoclcgdiis (l>'OKW,Ny, 1840) U = umbilical diameter Cymdtoccras kdvcdnm (Bi aneokii , 1861) Figures in parentheses are measurements as a percentage of (PI. 1, Fig. 2) total diameter. 1951 (.ynidtuicras kjya Bi \ni . Col l K.non : 13 (with syno­ The suture terminology is following k u l MANN & Wit l> nymy). MANN (1970): t = Internal lobe M aterial: One isolated fragment from Duela (Section V). U = Umbilical lobe D e sc rip tio n : The incomplete but nearly not deformed I, = Lateral lobe specimen contains half a whorl ot the phragmocon. The F. = Fxternal lobe measurements will be compared yvith those ot a specimen of comparable size, described by Speng LEK (1910: 1 271., Class Cephalopoda Cmil-R, 1797 specimen b) from the Cretaceous of South fndia.

Subclass Nautiloidea Ai.assix , 184^ D Wh Wh Wh/Wb U

C>rder Nautilida Agassiz , IS47 Yt 16/2 82 46(0.56) 49(0.60) 0.94 8(0.10) Sp in g iir (I9I0) 78 44.4(0.57) 44.5(0.57) 1.00 8.4(0.11) Supertamilv Nautilaceae nr Bi ainvii it, 1825 The coiling is moderately involute, the external side broadly Family Nautilidae Dh Bi ainvilie , IS25 rounded, the flanks are slightly llattened, the umbilical Genus Psciuloccnoccras Sl'ATH, 1927 shoulders narroxvlv rounded. Nearly no sculpture is visible,

Type species: Psvndou'nom\xs Lirgillicrtuinmn (p ’O kbu .nv , only nearby the umbilical shoulder there exist first signs ot 1840) relativ civ broad ribs. The suture lines are slightly curved, they show a wide and shallow lateral lobe, but cross the external Pscudnccnnccras aft. Lirgdhertmnum (d ’O rbigny , 1S40) side more or less straight. The half whorl shows approximately (PI. I, Fig. I) 9-10 suture lines. M aterial: Two isolated fragments front the higher part of the Zongshan Formation (Section D). D i s cu s s i o n : The tight coiling and the first signs of ribbing indicate that the genus is Cymatoccnts. The typical ribs are D e s c rip tio n : The specimens are incomplete, no exact not visible, but according to Spengi er (1910: 128) they' produce measurements can be given. The maximum diameter will be 'erst in einem vorgeschrittenen Wachstumsstadium auch Ein­ approximately 140 mm, the whorl section is broad and well drücke auf dem Steinkern’. rounded. The umbilicus is open, the umbilical wall nearly vertical. The diameter of the umbilicus may be nearly I 5"/» of Within the genus Cyuiatoccrdi there exists an excellent the total diameter. No sculpture is visible. The suture shows a correspondence with the species C. kdyCdtiiis concerning the broad and shallow lateral lobe and is more or less straight across measurements as well as the number and curvature of the suture the c enter. lines. C. kaycanus differs from the closely related species C. Tdduitits (J. SowtKBY, I 822) and C. dlbcnsn (d ’O kbigny , 1850) D is c u s s io n : The smooth shell, the open and steep especially in having more septa per whorl and contrary to the umbilicus, and the simple suture line show clearly that the species C. virgdtus (Spengi ER, 1910) the suture lines run genus is Pscudocowcenn. This genus has only few species, eight straight across the venter. are listed in kuMMEl (1956: 3S4f.). The fragments best correspond with the type species, C. Lirgillicrtianum. But in O c c u rre n c e : C. kdycdtuis has been described from the contrast to examples of this species, the Tibetan specimens seem middle and upper Albian of India and Madagascar. According to have a broader cross-section and the flanks are less flattened. to Basse (193 1: 9) the species has been found also in the lower O ccurrence: The genus Pscudoccnoccras has been Turonian of Madagascar. The Tibetan specimen comes from described in Europe from the Cretaceous of England to the sediments ot Upper Albian age. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at s 6

Subclass Anunonoide.t ZriTi i, 1SK4 D isc u ssio n : Because of the incompleteness and the bad preservation of the specimen it seems somewhat uncertain if Order Ammonitlda Ai.Asmz, 1 847 the subgenus is A. (Acoucccras) or A. (.Semmartmoccras) Suborder Ammonitiru FhAlT, 1XS9 Bonarli li, 1921. But the feeble ornament and the highly Superlamilv Haplocerataceae Z m i i , 1XS4 differentiated suture line correspond better with A. (A am ctcras). KlNNFDY & KllNOI R (1979: 117) give a list of Family Oppelndae H.D olyii i i , 1S90 species referred to this subgenus, but the poor preservation of Subfamily Aconcceratmae Spath , 1923 the Tibetan specimen will not allow an exact identification with one of them.

Genus Auwctcws H) ait , 1903 Occu rrcnce: A. (A aw (.¡jews) has been described widely from the Aptian and also the Lower Alhian of western Europe, Submenus Aonta.eras (Aiotivtvras) 1 1 'i AT! , 1 903 the former USSR, Nepal, northern Africa, Madagascar, South l y p e s p ec i e s : A . {Acunncrds) units (d 'O riikiny , IX41) Africa and Australia. The specimen of southern Tibet is from the Upper Aptian. Aamcccnis (Ac(»iccc)\ts) sp. (PI. 1, Fig. 3, Text-fig. 6) Superfamily Desmocerataceae ZlTTtl , 1S95 M aterial: One crushed and corroded specimen from the Family Cleomccratidae W hitehousi ■, 1926 Ganbadongshan Formation of the Gamba Group (Section A).

D escription: The crushed specimen probably had a diameter of less than 45 mm, but no exact measurements can Genus CvHhiboplitcs Spath , 1922 be given. The coiling is very involute with a small steep-sided T ype s p ec i e s: C ymahnplitcs kcrenskuvuts (Boi.osiowsky , umbilicus. The whorl section is high and strongly compressed, 1902) the flanks are distinctly flattened and the venter is fastigate. There exist dense week striae on the flanks, which are sigmoidal Cymahoplites sp. to slightly faleoid on the outer part. The surure line is highly (PI. 1, Pig. 4, Text-fig. 7) differentiated with deep narrow trifid lobes (tig. 6). M a te ria l: One single specimen from the basis of the Chaquiela bormntion of Gamba Group (Section A). D escription: The somewhat corroded specimen has a diameter of 50 mm. The coiling is rather evolute, the umbilicus nearly 20 mm (0.40). The cross section is compressed, with flat flanks, a rounded umbilical edge and also a rounded and somewhat flattened outer side. The dense and thin ribs are projected forward on the lower part of the flank, they are sinuous and also slightly proiected forward on the external side. The ribs start with weak and radially elongated nodes and branch often at the flanks. Also Tug. A: Suture line of Acout tcnis ( LowciV'.n) sp. (specimen Af 65/1, some intercalatories exist. Passing to the outer side the ribs see also pi. 1, tig. 3). are slightly thickening but weaker again on the external side.

Plate !

lug. 1: PscndoictmLcras aft. largilhcrtuunnu (d ’O kkk.m )• Section D (Zongshan Formation, 1)1 147/1); x 2/3. Fig. 2. ( ynhituiums kaytwun (Bi wiemn); Section V (Gamba Group ai Duela, Vt 16/2), a: lateral view, b: frontal view; x 1. Fig. 3: Aitmcicnn (. icnticteras) sp.; Section A (Ganbadongshan Formation of Gamba Group, At 65/1); x 1. Fig. 4: ( ymahtiphtcs sp.; Section A (Chaquiela Formation of Gamba Group, AI 76A/2); x 1. Fig. 5: Ilysh rtKL-hn >cnnlcvc I Iaas ; Section A (Chaquiela Formation of Gamba Group, At S4/1 ); x 2. Fig. (v. < allilmplitcs ictnignniis (Si i ! is); Section A (Chaquiela F onnation of Gamba Group, AI 172/1); x 1. Fig. i. C jlhhophtcs ( t. j’ltiisonotus (S lim ); Section A (('haquiela Formation of Gamba Group, Af 39/1); x 1. lug. S: Plcitrnbuphtcs (Plcnrohuphtvs) inbitsticnsLttits n. sp.; Holotype (It 1/1); Section 1 (Chaquiela Formation ot Gamba Group); x 1. Fig. V: Plcitmhophtcs (Plamihophtcs) rubiistuiuLttns n. sp.; Paratvpe (If 1/3); Section I (Chaquiela Formation of Gamba Group); x 1. lug. 10: I ommucrds libctn urn n. sp.; Flolotvpe (AI 1 S/l); Section A ((/haquiela Formation of Gamba Group); a: lateral view, b: ventral view; x 1. lug. 11: /.rimmuT.1) ubctuitm n. sp.; Paratvpe (Af 1X4/1); Section A ( haquiela Formation ot Gamba Group); x I. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at Zitteliuna 23. 2002 Plate I

Immel & H e: Cretaceous cephalopods of the Tethvan Himalaya of southern Tibet © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 88

U, E U-

V

\t

Dp, 7: Suture line of Cymahuphta sp. (specimen At 76A/2, see also pi. 1, lit;. 4),

The suture line shows .some details (tip. 7), especially the S tra tu m tv pi cum : Gamba Group, basal part of the broad external lobe, the likewise broad tnlid lateral lobe and Chaquiela Formation, probably within the range of upper the much smaller and simpler umbilical lobes. Lower Albian to lower Middle Albian. D iscu ssio n : The specimen is a typical Cymabopbtes in Diagnosis: Lemnroicras with evolutc coiling, subquad rate, size, coiling, shape and especially in the sculpture. This genus only slightly compressed whorl section and dense ribbing. is very close toLcmitroccras Slvvrn, 1942, which is according M aterial: One pood preserved and only a little corroded to Jn I r/K'i (1%4: SO) 'a |tinior synonym otCymabopbtcs'. specimen from the basal Chaquiela Formation of the Gamba But already C ams (1961: 167) has pointed out some Group (Section A). Another broken and somewhat crushed morpholopical differences between the two penera. So m specimen, probably the same species, is from the same section Cymabopbtcs the ribs are weaker and the primary libs are and formation, from a level 150 m deeper in the Chaquiela directed more radially and not so oblique m the lower part of Formation. the flanks. D e s c rip tio n : The holotvpe (pi. I, fig. 10) consists of The Tibetan species differs from all known species of almost one whorl. The following measurements can be given: Cymabopbtcs. Fear example, m contrast to the type species, C. kerenskiamts, the coiling is more evolutc, the ribbing on the D \Yh Wb Wh/Wb U outer part of the whorl is more dense, and the ribs are Af 18/1 36 12.5(0.35) 12(0.33) 1.05 13(0.36) commonly bifurcatinp at the lower flank while in ('. The coiling is rather evolutc, the whorl height increases kcrotsktamts the ribs are often singles. Probably the Tibetan slowly. The whorl section is suhquadratc, slightly compressed specimen is a new species, but because of its poor presen ation with flat and somewhat converging flanks and a tabulate it seems better to describe it in open nomenclature. external side. The greatest thickness of the whorl is at the distinct and slightly elongated umbilical tubercles. There exist O c c u rre n c e : Originally the genus was thought to be of nine at the last half whorl. Lower Albian or Middle Albian age (Wrioht 1957: 1.400), but in a short revision by C ash (1966: 551) 'the Lower Albian At each umbilical tubercle three, sometimes only tw'o, ribs dating of (.ymabnphtes' is conlirmed. hspceiallv there is an are bundled. Somewhat irregularly between two bundles a fur­ association with Lcymcnclla tarcicfitnata (Li vm irii , in ther rib is intercalated, starting at the lower part of the flank. d ’O khio N'i 1S41), the index species for the lower Lower All ribs are slightly sinuous on the flanks and straight across Albian. The genus is best known b om the former central (type) the external side. There are approximately 35 ribs on the last and southern LTSSR. Furthermore a ’septate fragment’ (Casi y half whorl. The suture line shows a prominent broad and deep 1961: 168) from England and some small, mostly fragmented bifid lateral lobe (fig. 8). specimens from Canada (Jl.I ITZKV 1964: pi. 24, fig. 10; pi. 26, The second specimen (pi. I, fig. I 1) is less well preserved. fig. 6, 10) have been described. The maximum diameter was approximately' 50 mm but no exact measurements can be given. Coiling, whorl section and type of ornamentation seem to be identical with the holotvpe. Only the umbilical tubercles and also the ribs are somewhat stronger. Genus Lemnroicras Scat 11, 1942 But this ought be because of its later ontogenetic stage. T \ pc species: Lemnroicras abitrense (Sl’Al n, 1933) D iscu ssio n : The specimens belong to Lcmitroccras, which has close relationships with the genus Cymabopbtcs Sl’ATH, Lctmiroicras tibctiaim n. sp. 1922 (see there). Characteristics forLcmitroccras are the strong (PI. I, Fig. 10, 11, Text-fig. S) ribbing and the obliquity of the elongated umbilical nodes. Also the slow increase of whorl height is a feature of H o I o t v p c : Af 18/1. Lcmitroccras rather than of Cymaboplitcs. De riv.itio nom inis:T he name refers to the region where Within the genus Lcnutroccras the Tibetan material can not the species was found. be identified with one of the known species. The combination fo c u s ty picu s: South Tibet, area of Gamba, lower part of evolute coiling, subquadrate whorl section and dense ribbing ot section A. is unique and may be reason enough to establish a new species. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 89

D escription: The holotype (pi. I, fig. S) has a maximum diameter ot 46 mm. The coiling is rather evolute, the umbilicus is 16 mm (0.35) wide. The cross section is compressed with Battened flanks. The greatest thickness is at the umbilical tubercles, the external side is tastigate. 1 )uc to poor preservation no exact measurements can be given.

At the umbilical edge ot the last whorl arise 13 somew hat elongated umbilical tubercles running oblique to the umbilical edge. At each two strong and rounded ribs start, the one cross Pi£. 8: Suture line ot Lemitrotn\i> tibetiutm n. sp. i holoupc, specimen Af 18/1, see also pi. i, ti£. 10). the flank straight, the other is convex at the inner Hank and straight on the outer flank. On the innermost part single ribs without umbilical tubercles are sometimes intercalated. All ribs bear strong tubercles which have a tendency to be clavi. The The closest .it t ini ties exist toL. spath Coli lic. non , 1949 and ribs are weakened at the external side but are not interrupted. /.. unibilicatum C olligni >xj, 1963. The latter has been regarded From the suture line nothing is visible. bv its author as a variation (subspecies?) ot L. spathi (see ( ollignon 1963: 97). L. spat hi lias a comparable dense ribbing Th e second specimen (pi. 1, fig. 9) probably is an inner whorl but a more involute coiling and a clearK more compressed ot the same species, with a diameter of 32 mm. At this earlier whorl section (see the measurements in Coi iig Mon 1949: 67). stage the coiling is the same, the umbilicus 1 1 mm (0.34). The In L. umbilicatitm the coiling is comparable to L. tibetiami external side seems to be more rounded but is also subearinate, (U = 0.34) but also the ribbing is less dense. Only in L. ditlnum the ribbing is somewhat denser with more intermediate ribs. Coi i k .non , 1949 the whorl section (Wh/Wb = 1.0) is compa­ 1 he ribs are less straight and more llexuous and are also rable but this species has also a closer coiling and the ribbing weakened at the external side. is much coarser. D iscu ssio n : The specimens have characteristics of both O c c u rre n c e : From L. tibctianu only isolated specimens subgenera of Plcuroboplitcs, P. (P lcuroboplitcs) and P. exist from southern Tibet. The stratigraphic position is (Arrbapboccras) WniTLHoux] , 1927. The compressed whorl presumably within the upper Lower Albian to lower Middle section and the persistancc of the external tubercles are typical Albian interval - in accordance with the known stratigraphic ot P. (Plcuroboplitcs) but the ribs which cross the external side range of the genus. without interruption are more a feature of P. (Arrbapboceras). This shows the close relationship between both forms which are regarded here as subgenera following W right (1957: L398 Supertamilv Hoplitaceac H. D oiiyiiii , 1890 and 1996: 1 17) rather than two separated genera as listed by Family H. Douvn 11, 1890 Ki nni in & 14 is (1978: VIO).

Subtamilv Anahoplitinae Bri istrohflr , 1947 Within P. (Plcuroboplitcs) the ornamentation with strong and rounded ribs, which cross straight the flanks and also the external side without interruption, is quite different to all Genus Plcuroboplitcs Spath , 1921 known species, tn the type species, P. (P.) renauxianus, the ribs Subgenus Plenroboplitcs (Plcuroboplitcs) Spath , 1921 are finer, concav e and interrupted on the external side. P. (P.) cpigonus Spath , 192S has also strong ribs. But this hardly Type species:P.(Plcuroboplitcs)miatixianiis(i>’C>RBIGNY, 1S40) known species has a wider ribbing and a subtabulate external side where the ribs also are interrupted.

Plcuroboplitcs (Plcuroboplitcs) robusticostatus n. sp. Occurrence: P. (P.) robusticostatus is known only from (PI. 1, Fig. 8, 9) the Upper Albian of southern Tibet. The stratigraphic range is suggested only because this subgenus is constricted to this H o I o t y p c : If 1/1. period of time. D e n y at 10 n o m in is: The name refers to the strong ribs which are unusual in the subgenus.

Locus ty p icu s: South Tibet, area of Gamba, section 1. Subfamily Hoplitinae Ft. D ouvilll , 1910 Stratum typicuin: Chaquiela Formation of Gamba Group, probable- Upper Albian. Genus Callihoplites Spath , 1925

Diagnosis: P. (Plcuroboplitcs) with a relatively dense Type s p ee i es: Callihoplites catdlus (J. Hi C. SowFRBY, 1827) ribbing. Ribs strong and rounded, crossing the external side without interruption. tn the lower part of the Gamba Group of section A more M aterial: From the Gamba Group section 1 (not measured) than a dozen specimens of the genus Callihoplites are preserved four specimens belong to the subgenus P. (Plcuroboplitcs). Two as crushed external moulds of which rubber casts have been ot them can be identified as belonging to a new species. Both made. They are concentrated near the top ot the Chaquiela of these are preserved as external moulds ot which casts have Formation of Gamba Group (Section A). been made. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 90

Calliboplites tctragomis (Seeley , 1865) uncertain. However, these specimens are different from C. tetragoniis, described above, in its relatively fine and dense (PI. 1, Fig. 6) ribbing as well as in the smaller outer tubercles. 1928 Calliboplites tctragomis (Si tin') - Spath : 210; pi. 22, fig. 1-2, 9-10; pi. 23, tig. I!(?); text-fig. 66 (with synonymy). O ccurrence: The species C. glossonotus is known from the Upper Albian of southern England. A taxon called M a te ria l: More than half a dozen of the mentioned 'Calliboplites cf. glossonotus (Seeley ) Spath ’ is mentioned also specimens of Calliboplites belong to this species. from the Kirchrode I borehole, northern Germany(W iedmann & D e sc rip tio n : Exact measurements can not be given. The O wen 2001: 167). maximum diameter was almost 50 mm. The coiling is moderately evolute, the external side seems to be rounded. There are strong umbilical tubercles, 12-13 per half whorl. Superfamily Acanthocerataceae Grossouvre , 1894

From each tubercle arise 2-3 ribs, which cross straight or Family Brancoceratidae Spath , 1934 slightly flexuous the flanks. Often two are looped and end at Subfamily Brancoceratinae Spath , 1934 ventrolateral tubercles, which are somewhat clavi. Of the suture line nothing is visible. D iscu ssio n : Size, coiling and sculpture are tvpical for the Genus Hysteroccras H yatt , 1900 genus Calhboplitcs, which is very similar to Dnnoipbophtes Tv p e species: Hysteroccras varicosum (J. de C. Sowerby , 1S24) Spath , 1925 but can be distinguished bv means of its slight!v rounded external side. Within Calliboplites a complete correspondence is seen to C. tctragom is, especially to C. Hysteroccras seniileve H aas , 1942 tctragomis var. vulgaris Spath , 1928 (p. 212; pi. 22, fig. 1). (PI. 1, Fig. 5) Characteristic is the throughout coarse ornamentation, the 1942 Hysteroccras seniileve, forma typica - H aas : 42; pi. 5, fig. 19; short and only very slightly falcoid ribs and the prominent pi. 7, fig. 8-11; text-fig. 5c, 5h. inner and outer tubercles. Also C. anntus (J. Sowerby , 1S16) has a coarse ornamentation, but the costation of this species 1942 Hysteroccras semileve var. sparsicostata -1 Iaas : 44; pi. 5, fig. seems to be more regular and the outer tubercles are all ’clavi 22; pi. 7, fig. 13; text-fig. 5g-h. parallel to the ventral edges’ (SPATH 192S: 212). 196S Hysteroccras semileve H aas - Ri nz : 63; pi. 11, fig. 6; text-fig. Occurrence: C. tctragomis has been described front the 22g-h. Upper Albian (dispar Zone) of southern England. M a te ria l: More than a dozen specimens of the genus have been found in one level at the top of the Chaquiela I ormation of Gamba Group (Section A), some of which can be identified at species level. Calliboplites cf. glossonutns (Seeley , 1S65) (PI. 1, Fig. 7) D e sc rip tio n : All the specimens are small (diameter ma­ ximal 20 mm) and crushed, therefore no exact measurements M aterial: Nearly half a dozen of the referred specimens can be given. The coiling is rather involute with a shallow of Calliboplites are closely related to C. glossonutns. umbilicus and steep umbilical walls. The flanks are flattened D e sc rip tio n : The diameter is approximately 50 mm, the and the outer side is keeled. There exist broad flattened ribs, coiling rather evolute. An exact reconstruction of the cross starting out almost in pairs, rarely as single ribs at small section and exact measurements are not possible. The sculpture umbilical nodes. The ribs are very weak at the lower flank but consists of dense and somewhat sigmoidal ribs, strong strong at the outer side where they are projected somewhat umbilical nodes, 13-14 per half whorl and smaller outer forward. Per half whorl there are 14-15 ribs between which tubercles. Nothing is visible of the suture line. the intercostals are somewhat smaller. CM the suture line not­ D iscu ssio n : The specimens can be compared best with hing is visible. C. glossonotus (see Spath 192S: 223; pi. 23, fig. 2; text-fig. 72, D is c u s s io n : The micromorph specimens are clearly with synonymy), but this species is poorly known. Contrary related to the genus Hysteroccras from which Spatbiceras to the specimen figured by Spath , the Tibetan material seems W hitehouse 1927 can be regarded as a junior synonym to be more evolute, the whorl height is increasing slower and (Cooper & Kennedy 1979: 267). The rather involute coiling, the costation is somewhat more irregular. As nothing is known the number of broad ribs and there projection at the outer about the variability of the species the identification is flank have the best correspondence with H. semileve and its

Píate 2

Fig. 1: Mortomceras (Demnloieras) bispmusitm (Spath ); Section V (Gamba Group at Duela, Vt 16/3); a-b: lateral views, c: ventral view; x 2/3. F ig. 2: Mortvimeras (Mortonucras) pruei (Spath ); Section V (Gamba Group at Duela, Vf 15/1); x 2/3. I ig. 3: Mortomceras (Mortomceras) rostratum (J. SowtRin); Section V (Gamba Group at Duela, Vf 16/1); x 2/3. Fig. 4: Mortomceras (Mortomceras) mtermcdutm Spath ; Section V (Gamba Group at Duela, Vt 17/1); x 2/3. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at Zitteliana 23, 2002 Plate 2

Immel & H i: Cretaceous cephalopods ot the Tethyan Himalaya of southern Tibet © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 92

var. sparsnostata. The most closely related species, H. Mortoniccras (Mortoniccras) pricci (Spath , 1922) proptnr/unin H aas , IM42, may be distinguished by its weaker (PI. 2, Fig. 2) ribs which are also straight and not distinctly sigmoidal. 1999 Mortoniccras (Mortoniccras) pricci (Sl'ATH, 1922) - kENNrny O cc u i re n c e : II. scmilcve (including several Varieties') has et .'ll.: 1 109, fig. 8-9, 10.6 (with synonymy). been described from the Upper Album of Madagascar and M aterial: One specimen of nearly halt a whorl from the Switzerland. calcareous facies within the Ganiba Group at Duela (Section V).

Subfamily Mortoniceratmac H. D uuvtli f, f 912 D escription: The maximum diameter has been approximately 180 mm, the exact whorl section can not be reconstructed. The strong ribs are most simple, somewhat Genus Mortoniccras M i-f.k , 1876 irregularly alternating long and shorter ones, or rarely also Subgenus Mortoniccras (Mortoniccras) Mfl-K, 1876 bifurcating at umbilical nodes. The long ribs start all at radially' elongated umbilical tubercles. All ribs are very slightly falcoid Tv P e species: M. (Mortoniccras) vespertinum (Mi irt< >n , 1834) on the flank but stronger projected fortvard at the outer shoulder. They all bear ventral nodes. Only some details of Mortoniccras (Mortoniccras) intermedium Spath , IM32 the suture line are visible. (PI. 2, big. 4) D iscussion: The specimen agrees xvell rvith M. (Mortoniccras) pricci as described by Spath (1932: 39 Iff.) and 1971 Mortoniccras (Mortoniccras) pricci aft. intermedium Sl'MI-l - others. M. (M.) pricci is closely related to M. (Mortoniccras) Rl\/: 599; pi. 6, fig. I, 2(?); pi. 7, hg. 2; text-fig. 51, 7f (with intermedium Spypi i, 1932 (see discussion there). But in contrast synonymy). to this species M. (M .)pricci has a denser ribbing on the outer 199S Murtonieeras (Mortoniccras) price! intermedium Spath - whorl and more sinous ribs. Also it lacks lateral tubercles and Wii dm ANN & I )ukr : 21, tigs. 3 B-C, 4 A (with synonymy). the umbilical tubercles are ontogcneticallv longer prominent. M a t e r i a I: C )nc specimen from the calcareous facies within Occurrence: M. (M.) pricci is widely distributed and the Ganiba Group at Duela (section V). knosvn from western I urope, Poland and the former USSR, D e sc rip tio n : The well preserved specimen is somewhat as yvell as from northern Africa, Nigeria, Madagascar, Texas broken and flattened. The diameter was approximately fSO and Venezuela. The species is restricted to the lorver Upper mm. The coiling is very evolute and the whorl section Albian (inflatum Zone). compressed but no exact measurement is possible. On the inner whorl there is a somewhat irregular alternation of the dense ribs, bifurcating at umbilical nodes or intercalating Mortoniccras (Mortoniccras) rostratum (J. SoWLRBY, 1817) on the lower part of the flank. All ribs have small lateral (PI. 2, Fig. 3) tubercles and bigger ventrolateral ones. On the outer whorls 19S5 Mortoniccras (Subschlocnbacbia) rostratum (J. Si avprby 1817)- the simple straight ribs are more distant, mostly beginning at Immh & Si iid -Fmami : 96; pi. 3, fig. 2 (xvith synonymy). umbilical nodes or starting at the lower flank, alway s with small lateral and heavy ventral tubercles. No details of the suture 1998 Mortoniccras (Subscblocnbacbia) rostratum (J. Si >yxTRBS, 1817)- line are visible. ki nni in et al.: 17, figs. 9-11, 13-18 (yvitli svmmymy). D iscussion: The best agreement exists with M. 1998 Mortoniccras (Mortoniccras) rostratum (ScWYERBy, 1S17) - (Mortoniccras) intermedium in size, coiling and the sculpture Maixlmoi 'ii et al.: 176, figs. 4-7 (with synonymy). with straight tubcrculate ribs, closer at the inner whorls and M ateria l: Two isolated specimens from the calcareous more distant at the later stages (see number and direction of facies within the Gamba Group at Duela (Section V). ribs by Spath 1932: pi. 38, fig. 5 for a smaller specimen and D escription: The better preserved specimen has a Rl NZ 1971: pi. 6, fig. la for a larger one). diameter of I 15 mm. The coiling is evolute, the umbilical In the interpretation ofS pa PH (1932: 392) and later authors, diameter 43 mm (0.37), the yvhorl section can not be measured M. (M.) intermedium us only a subspecies of M. (Mortoniccras) because of secondary flattening. The ribs are first close, sim­ pricci Spaph , 1922 and a transitional form toM. (Durnovantcs) ple or branching at the umbilical edge. After a diameter of kiliani (Lasxwit /, 1904). But from the first it could be nearly 60 mm the ribs become stronger and distant, finally distinguished for example by the precence of weak lateral there are I 1 ribs per halt yvhorl. All ribs are tubcrculate, on the tubercles (sec also discussion there), whereas the latter is not inner yvhorl they mav be quadrituberculate, later on they are consistent with the definition of the subgenus treated here, clearly trituberculate, yvitli small umbilical and lateral and pro­ especially because of its quadrituberculation. minent ventral nodes, the latter developing to be clavate. Only Occurrence: M. (M.) intermedium has been described few details of the suture line are visible. from the Upper Albian of South Kngland, Madagascar, Vene­ D iscussion: There is good correspondence yvitliM. (M.) zuela and also from the Xigaze Group of South Tibet. The rostratum in measurements (see Spath 1932: 401) and species may be restricted to the inflation Zone. development of the sculpture. Especially the rapid formation © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 93 of distant single ribs is characteristic and the best argument to D escription: The specimens are incomplete and distinguish the specimens from Mortoniceras (Mortoniceras) somewhat crushed, therefore no exact measurements can be inflation (J. Sowi rby , ISIS). given. The best preserved specimen (pi. 3, tig. 4) had a diameter O c cu rrence: d/| ( \1.) rostration has been described from of approximately 140 mm and a subquadrate whorl section, a little higher than wide. At first nearly all ribs arc bifurcating at the Anglo Paris basin, I lungary, former southern USSR, and the umbilical nodes which are somewhat elongated radially. central Iran as well as Angola, Madagascar, Japan and Texas. Later on single ribs are sometimes intercalated. All ribs bear The species is restricted to the uppermost Albian (dispar Zone). external nodes, slightly projected tangentially. The suture line is nearly invisible. Subgenus Mortornccras (Deiradoccras)an \ H otPi n , 1931 D iscu ssio n : The specimen is matching ,1/. (D.) devonense Type species: M. (Deiradoccras) prerostra turn Spath , 1921 in coiling, whorl section and sculpture. Especially there is some similarity with the variety compressa described lrom southern England (Spath 1932-33: 420; pi. 39, tig. 1). M. (D.) devonense Mortornccras (Deiradoccras) bispinosum (Spath , 1921) can be distinguished from the closely allied species M. (D.) (PI. 2, Fig. 1) bispinosum (Spath , 1921) by the whorl height which is in­ creasing faster, and the projection of the external nodes. 1975 Mortornccras (Deiradoccras) bispinosum (Spath , 1921) - F> >K- STl R: 22S; pi. 12, tig. 2, 5; text-fig. 73 (with synonymy). Occurrence:^. (D.) devonense is known from the Upper M aterial: One specimen from the calcareous facies within Albian ol western Europe, South Africa and Venezuela. In Eng­ land and France the species is restricted to the lower Upper the Carnba Group at Duela (Section V). Albian (inflation Zone). D e sc rip tio n : The specimen consists of more than halt a whorl and is nearly not crushed, so that some measurements can be given. These are compared with those of the type species Subgenus Mortoniceras (Durnovantes) Spath , 1932 (Sp ytti 19 21: 285) as lollowing: Type species: Mortoniceras (Durnovantes) pennflatum I) Wh Wb U (Sl'ATH, 1922) Spath 1921 I4S (0.32) (0.30) (0.44) Vf 16/3 134 42(0.31) 39(0.29) 61(0.46) Mortoniceras (Durnovantes) kihani (L.ASSW1TZ, 1904) The coiling is evolute, the whorl section subquadrate. The ribs are strong, more or less alternate simple or bifurcating at (PI. 3, Fig. 1) strong umbilical nodes. All ribs bear external tubercles. On 1932 Mortoniceras (Pervinquicna) kihani (L asxwitz ) - Spath : 408; the outer side there are 19 ribs at a half whorl. This is some­ pi. 38, lig. 1, 2; pi. 42, fig. 1; pi. 47, fig. 1; text- fig. 140 (with what more than in the two complete specimens figured by synonymy). Forster (1975: pi. 12, fig. 2, 5), but these are of a smaller size. M aterial: One isolated specimen, found several meters out Only some details of the suture line are visible. of section G in the same facies of the Chaquiela Formation of D iscu ssio n : Coiling, measurements and sculpture agree the Gamba Group. very well with the data given by Spath (1921) for a specimen D e sc rip tio n : The diameter was something less than 100 of Zululand and two specimens ol southern Mozambique, mm, the coiling is rather evolute. No exact measurements can described by Forster (1975). M. (D.) bispinosum is most be given because the specimen is somewhat crushed. The similar to the type species M. ID.)prerostratum (Spath , 1921). section is subrcctangular with parallel flanks, broad and keeled This species is distinguished lrom M. (D.) bispinosum by the external sides and a deep umbilicus. The ribs are ntostely coarser ribs and the umbilical nodes being situated higher on bifurcating at the umbilical edge. They bear four tubercles: the flanks. But one should note that according to Forster umbilical, lateral, marginal and external. At a diameter of (1975: 229) there exist transitional specimens between the two approximately 65 mm there exist 2 1 ribs and 1 I umbilical nodes species. per half whorl. The suture line is not visible. Occurrence: .1/. (D.) bispinosum has been described so D iscu ssio n : In coiling, cross section and sculpture the far from the lower Upper Albian of South Africa, southern specimen is a typical M. (D.) kihani. The holotype of this Mozambique and Madagascar. species has the same number of ribs and umbilical nodes at a comparable size (see Spath 1932: text-fig. 140). According to Spath (op. cit.: 40S) M. (D.) kiliani may 'be somewhat Mortoniceras (Deiradoccras) devonense Spath , 1933 transitional' to Mortoniceras (Durnovantes) pachys (Seeley , (PI. 3, Fig. 4) 1S65). But from this species M. (D.) kihani can be distinguished 1971 Mortoniceras (Deiradoccras) devonense Spath - RtNZ: 605, because it is less densely ribbed and has a more inflated cross pi. 10, fig. 1; pi. 11, fig. 2; text-fig. 6a, 6b, 7d, 7k (with section. synony my). Occurrence: M. (D .) kihani has been described front the M a te ria l: Three specimens from the calcareous tacies Upper Albian of Texas and Southern England. It is also within the Gamba Group at Duela (Section V), in one ol which mentioned from Poland (see Marciniowski & W iedmann the identification is somewhat uncertain. 1990: SS). © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 94

Genus Goodhallites Spath , 1932 tubercles, but also some secondary ribs begin higher on the flanks. All ribs are widening at the outer flank and end in broad Type species: Goodhallites goodhalh (J. Si >\\ i Kin, 1820) ventrolateral nodes. At first the ribs are straight and nearly interrupted on the midtlank, but later on they are falcoid and Goodhallites procentm (\AN H im-pen , 1942) externally projected forward. Of the suture line no details are visible. (PI. 3, Fig. 2) D iscussion: The best correspondence is found with G. 1942 Lctlieccrasprocentm n. sp. - \ a \ I F >t i-ln : 149, tcxt-11y;. 192­ graallim um, a form which was compared by- Spath (1934:472) 193. with the inner whorls of the subgenus Mortomccras M Ate ri .11: One f ragmen tar v specimen from the calcareous (Deiradoceras) VAN I ioi PI N, 193 1, but belongs to Goodhallites facies within the Gambia Group at Duela (Section V). according to Fokstfr (f975: 240). He regarded this genus as a D e sc rip tio n : The broken and crushed specimen has a subgenus of Prohysteroceras Spath , 1921 as Wright (1957: L diameter of approximate! v 80 mm, the whorl section cannot 406) has done previously. be reconstructed exactly. The coiling is relatively involute Because of the crushed and incomplete preservation the (umbilical diameter approximately 25 mm). The ribs arc- species identification seems not quite sure. Especially the straight to slightly sinuous. They start at small umbilical closely related species G. hesakatrcnse C o u ignon , 1963 can tubercles or are intercalated on the flanks. They get wider to be distinguished only due to its more compressed cross section the outer side and terminate before reaching the keel m heavy and the more straight and slightly broader ribs. nodes. Only some relics of the suture line can be seen. O c c u rre n c e : The species G. graallim um is known from D iscu ssio n : Size, coiling and presumed whorl section, the Upper Albian of southern India, southern Mozambique, with a little bit convergent flanks, and sculpture are typical of and somewhat questionable from South Africa. Lctbcccras van Hoi-pin , 1942, which is regarded as a junior synonym of Goodhallites bv Wright (1996: 142). Family Dl Grossouvre , 1 S94 Within this genus the best match is found with G .procentm in size, involution and number of ribs per half whorl (15-16). Subfamily Mantelhceratinae H yatt , 1903 There are some species very similar toG.procentm, especially Genus Mantelhceras Eh ATT, 1900 G. densieostatitm van H oe pi-n , 1942 and G. proxmutm van Ty pe species: Mantelhceras mantelh (J. Si'WI.RBY, 1S14) H i 11-pfn , 1942. The first can be distinguished from G. procentm by the greater number of ribs per halt w horl (20), the latter bv the slender ribs and the smaller external nodes which become Of this genus exist four specimens, two each of sections B more clavate. and G of the Ganbacunkou Formation of the Gamba Group, Occurrence: G. procentm has been described only from but only the two specimens of section B can be identified on the lower Upper Albian of Zululand (South Africa). species level.

Goodhallites cf. graallnnum (koxsMAT, 1895) Mantelhceras ct. m antelh (J. Sowekby , 1814)

(PI. 3, Pig. 7) (PI. 3, Fig. 6) M a t e r i a 1: hour specimens from the uppermost part of the M at e ri a l: One isolated fragment of nearly halt a whorl of Chaquiela Formation of Gambia Group (Section A). the pluagmocone from section B (Ganbacunkou Formation D e s c rip tio n : All specimens are crushed and mostelv of Gamba Group). incomplete, so that exact measurements can not be given. The D escription: The slightly distorted specimen had a maximum diameter has been approximately 55 nun. The coiling diameter of approximately 45 mm. The coiling is moderately is rather evolute, the whorl height increases rapidly . The flanks involute, the whorl section somewhat depressed with flattened are flattened, the outer side is keeled. Most of the rilas are flanks and ventral sides. The sculpture consists of 16 alternating starting in pairs or as single ribs front distinctive umbilical long and short ribs with umbilical, lower and upper

Plate 3

Fig. 1: Mortomccras [Dtirnovarttcs) ktham (I yssyyn/); Section G (Chaquiela Formation of Gamba Group, Gf 19/1); a: frontal view, b: lateral view; \ I. 1 ig. 2: (¡oodhalhtcs proicntm \A\ Hi n pin ; Section V (Gamba Group al Duela, Vf 17/2); x 1. Fig. 3: rttcalycocnas colhgnom (Fakki ); Section B (Ganbacunkou Formation ot Gamba Group, Bl 74/1), x I. Fig. 4' Mortomccras [Deiradoceras) di-concnse Spath ; Section V (Gamba Group at Duela, Vt 17/3), x 1. Fig. 5; Mantelhceras lymciisc (Spa ill); Section B (Ganbacunkou Formation of Gamba Group, Bf 31/1); a: ventral vierv, b: lateral view; x 1.

Fig. 9: Mantelhceras cf. mantelh (J. Si i\\ i r ip, ); Section B (Ganbacunkou Formation of Gamba Group, Bf 35/1); a: ventral view, b; lateral r iew; \ 1.

Fig. ~t: (jnodhalhtes cf. ytacdhmum \I\i issm ai ); Section A (Ghaquic-la Formation of Gamba Group, Af ISOM), x 1. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at Zittcliana 23, 2002 Plate 3

:■ p m h

Immei & H i: Cretaceous cephalopods of the Tcthvan Himalaya of southern Tibet © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 96 ventrolateral tubercles. No lateral tubercles are visible, perhaps D escription: The better preserved specimen has a due to corrosion. The suture lines are well preserved. diameter of approximately 75 mm, but no exact measurements can be given. The coiling is moderately involute, about half of D isc u ssio n : The specimen is clearly a Mantelhccras. 1 he the previous whorl being covered. The whorl section can not closest similarity is found with the tvpe species M. mantclh be reconstructed exactly but was probably compressed with because of its small size and coiling, the slightly depressed flattened flanks. whorl section and the density of the ribs. But there is a little difference in tuberculation (lacking of lateral tubercles) and There are long ribs, seven on the last quarter ol the whorl, the preservation is too poor; so the determination can not be which arise from sometimes elongated umbilical tubercles and sure. pass across the flank with gentle flexing. They are separated by one or almost two intercalated ribs of quite irregular length Occurrence: .1/. m antclh is the index species for the starting from below mid-flank. At first all ribs are bearing lowermost standard zone of the Cenomanian and has a distinct lower and upper ventrolateral tubercles, which will widespread distribution m Europe, Africa and Asia as stated be lost at the end of the whorl. Sometimes there are indications by Immh & S n ED-E m AMI (1985: 99), Kjnnidy et al. (1986: of siphonal tubercles. The sutures are not visible even at the 27), and Immi-l (1987: 103). better preserved specimens. D isc u s sio n : Coiling and sculpture are typical tor the Mantelhccras lymense (Statu , 1926) genus Eitcalycoecras. The density of the ribs and the clavate (PI. 3, Pig. 5) form of the ventrolateral tubercles are most similar toE. colhgnom. From this species the rather similar type species E. 19.86 Mantelhccras lymense (Statu ) - K.I N\nn,JuntNt r& Wright: 27; fig. 5a-f, tig. Ad-c; lig. 16c -1 (with svnonvmy). pentagonnm is separated in having more flattened ribs with smaller interspaces. Also there is some similarity toE. M aterial: One moderately preserved fragment, a quarter gotbicitm (Ki >ssmat , 1S95), but this species can be distinguished of a whorl of a phragmocone from section B (Ganbaeunkou from E. colhgnom bv the strong projection of the umbilical Formation of Gamha Group). tubercles into the umbilicus. D escription: The diameter o 1 the specimen was O c c u r r e n c e: E. colhgnom has been described previously approximately 100 mm. Exact measurements are not possible. only from the Upper Cenomanian of SE-I ranee. The whorl section is subrcctangular, slightly wider than high, with flattened flanks and a tabulate venter. The umbilical wall is vertical. The ribs, regularly long and short, are coarse and Family Collignoniceratidae Wright & W right , 195i straight. There are only strong elongated umbilical nodes and Subfamily Texanitinae Collignon , 1948 rather weak upper ventrolateral tubercles. Parts of the suture are preserved. Genus Sitbmortomccras Statu , 1926 D iscu ssio n : The specimen can best be compared with M. Tvpe species: Sitbmortomccras zcoodsi (SPATH, 1921) lym ensc\ a synonym of Mantelhccras costatnm (Mantlii , 1822) (which is invalid due to homonyms) according to Sitbmortomccras tcnmcostidatum Cot I k NON, 1948 W right & Kinnidv (1984: 102). The whorl section, the straight and coarse ribs and especially the rare tuberculation (PI. 4, Fig. I) are important points for this identification. 1970 Sitbmortomccras taimcostttLuttni C< >u . - Collignon : 44; pi.

Occurrence: M . lymense is widespread in the Lower 176, tig. 2317 (with svnonvmy). Cenomanian of western Europe, the Central Iran and Tunesia. M aterial: Two isolated specimens from the upper part of section C A (middle Zongshan Formation), one of which is poorly preserved and corroded, the other is a well preserved phragmocone. Subfamily oi Grossouyrl , 1894 D e s c rip tio n : From the better preserved specimen the Genus Eitcalycoecras Statu , 1923 following measurements can be given:

Type sP ecies: l ucalycoccras pentagonnm (Jum -s-Brow NL, D Wh Wb Wh/Wb U 1 896) CAf 74/1 112 46(0.41) 37(0.33) 1.25 35(0.31)

The coiling is moderately evolute, the whorl height increases Eitcalycoecras colhgnom (Fahre , 1940) rapidly. The whorl section is compressed with flattened flanks and external side, and an overhanging umbilical wall. The (N. 3, Fig. 3) pentatubereulate ribs are dense, starting simple or bifurcating 1972 F ucalycoccras (Eitcalycoecras) colhgnom (Fabre ) - T iiomi l: at strong umbilical tubercles. They pass across the flank slightly 85; pi. 27, tig. 7 (with synom my). prorsiradiate and end on clavate external tubercles. M aterial: Four specimens from the genus are from the Additionally weak lateral, submarginal and marginal tubercles upper part of the Ganbaeunkou Formation of Gamha Group exist. The ornament seams to be attenuated on the outer whorl. (Section B), but only two crushed fragments can be identified The sutures are not distinct but appear to be of normal at the species level and belong to here. texanitid type. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 97

D iscussion: The tight coiling and ornamentation, O c c u rre n c e : The genus Toxoceratoides ranges from the especially the attenuation oi the latter on the outer whorl, show Upper Barremian to the Upper Aptian and is known from that the specimens belong to Sitbmortomceras. The compressed Hurope, California, Mozambique, South Africa and Patagonia. whorl section and the fairly narrow umbilicus is most similar The Tibetan specimen is from the Upper Aptian. to S. tennicostitlatiim. As discussed broadly bv Ki-nnidy & Klinger (in Kt nnedi , Kauffman & Klinger 1973: 103) and Kl ingfr & Kennedy (1980:253ft.) this species mat be included Genus Tonobamitcs Spath , 1924 as a junior synonym in the type species S. zcoodst, but till now this is an unresolved problem. Type species: Tonobamitcs decitrrens Spath , 1924 Occurrence: S. tennicostitlatiim has been described from the middle Campanian (Zone of Pachydisats grossoiivrci) of Tonobamitcs mitltititberailatns n. sp. Madagascar. (PI. 4, Fig. 3, 4) H o lo ty pe: Af 71/8.

D eri vat 10 n o n n n is: The name refers to the numerous Suborder Ancvloceratina W iedmann , 1966 and long persisting nodes, which are unusual tor the genus.

Superlamilv Ancvlocerataceae Gill, 1S71 L ocus ty picus: South Tibet, area of Gamba, section A.

Family Ancyloceratidae Gill, 1871 S tratu m ty p ic u m : Gamba Group, middle level of the Ganbadongshan Formation, Upper Aptian. Subfamily Hehcancyhnae H yatt , 1894 Diagnosis: Tonobamitcs with regular trituberculate ribs on the whole shaft. Genus Toxoceratoides Spath , 1924 M aterial: Two specimens from a middle level of the Type species: Toxoceratoides royeriamtm (d ’O rbk ,nv , I 842) Ganbadongshan Formation of Gamba Group (Section A). D escription: The holotvpe (pi. 4, fig. 3) is a nearly Toxoceratoides aft. royeriamtm (d ’O rbigny , 1842) complete and only' slightly crushed specimen, existing as a (PI. 4, Fig. 6) cavity in a concretion, from which a cast was made. The se­ cond specimen (pi. 4, fig. 4), also a cast, is less complete and M a te ria l: One fragment from the middle part of the somewhat more crushed. Ganbadongshan Formation of Gamba Group (Section A). For The coiling is toxoceratid in the sense ofA guirrf . U rreta the most part it is only a cavity in a concretion from which a cast was made. (19S6: 282, fig.7). The holotvpe has a maximum height of 47.5 mm. The rvhorl section of the shaft is somesvhat ovoid, on the D e s c r i p t i o n : The fragment consists of a part of the nearl y hook becomes subcircular. The broadly rounded ribs are straight shaft and the beginning of the hook. The whorl section straight on the initial spiral and slightly prorsiradiate on the of the shaft is subcircular, the hook is somewhat compressed shaft. There are 5-6 ribs within a distance equal to the whorl and subrectangular. On the shaft the prorsiradiate ribs are height. alternatively primaries, with weak umbilical, and stronger la­ On the early1 spiral and on the shaft all ribs bear small and teral and external nodes, and weaker nontuberculate rounded umbilical and lateral tubercles. Where the external intercalatories. Between the umbilical and lateral tubercles and side can be seen, there exist also a rorv of external tubercles, so also between the latter and the external ones, the primary' ribs the species is - at least at times - trituberculate. At the beginning may be looped. On the hook the tuberculation of the ribs of the hook the lateral and external tubercles disappear and disappears, the external tubercles at last. Ol the suture line only some ribs still bear weak umbilical nodes. Of the suture nothing is visible. line nothing is visible. D iscu ssio n : The alternation of strong tuberculate and fine D iscu ssio n : The generic allocation of the specimens is nontuberculate ribs is typical for Toxoceratoides, contrasting somewhat difficult as they share characteristics of Tonobamites the closely allied Helicancylits Gabb , 1S69 and Tonobamttes and Helicancylits Gabb , 1869. The presence of trituberculate Spath , 1924 (see th ere). ribs on the shaft would be characteristic for Helicancylits, but A list of species belonging to Toxoceratoides is given bv contrary to this genus the tubercles are altvavs very weak. Also Klinger & Kennedy (1977: 307) and A guirrf U rreta (19S6: the broad and rounded ribs rvluch are llattened on the final 2961.). The best correspondence is seen in the tvpe species T. hook are features of Tonobamites rather than of Helicancylits. royeriamtm, especially the very regular alternation of primaries Within the genus Tonobamites the frequent and regular and intercalatories, the looping oi the primary ribs on the shaft tubercles are unusual and can not be compared with any known and the rapid expansion of the whorl on the final hook. But species. contrary to the French type species, the whorl section is compressed in the Tibetan specimen and not depressed and A species of some similarity' is T. acc/iticingnlatiis (von also on the final hook the umbilical tubercles disappear (see Koenln , 1902), some ol its ribs 'in the early stage ... bear the neotvpe ofT. royeriamtm in Casey 1961: 79f. and text-fig. siphonal, lateral and umbilical tubercles' (A guirri - U rreta 30a-c). 19S6: 3 10). But this tubercles also disappear earlier than in the © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 98

Tibetan species. Also the interspaces between the ribs are wi­ O c c u rre n c e : The genus Helicancylits has been described der in T. dequiangulatiis which has only 4 ribs within a distance from the Aptian of southern England, northern Germany and equal to the whorl diameter contrary to 5-6 in T. nntlti- Switzerland as well as front California (type species), Patagonia tuberculdtus. and - somewhat questionable - . Occurrence: T. »inltiliibcrcuLitus is known only from the Upper Aptian of southern Tibet. The stratigraphic position is Superfamilv Turrilitaceae Gill, 1871 fixed because the species is associated with C. (Chelomccras) Family Turrilitidae G ill, 1S7I aft. bnxtorfi (Jacob , in JAc ob & T oblek 1906), Colnmbiceras cf. subpeltoccrouics Sinzi >\\, 1907, and Pambophtes tnuitscholdi (Sink iNovuxH, Bam -vitxh ik Sorokin , 1876). Genus Proturrilitoides Breistroh er , 1940 Type species: Proturrilitoides asticrianits (l>'C fRBIGNY, IS42)

Genus Hclu,uicylus£jMsv>, 1869 Proturrilitoides sp. Type species: Heltcaueylus dequieostatus (G \BB, 1864) (PI. 4, Fig. 13) M aterial: Cine incomplete specimen, an external mould Hclicdncylus sp. from the Chaquiela Formation of Gamba Group (Section I). (PI. 4, Fig. 5) D e sc rip tio n : The Iragment is 15 mm high, the coiling M a te ria l: One fragment from the middle part of the loose, the apical angel is large (nearly 55"), the whorl section Ganbadongshan Formation of Gamba Group (Section A). It can not be reconstructed exactly. The oblique and non is preseryed as a cavity in a concretion from which a east was tuberculate ribs are strong, simple and fle.xuous. There exist made. approximately 12 ribs per half whorl. Of the suture line no­ D e sc rip tio n : The fragment is a 34 mm long part of a thing is visible. slightly curved shaft. The whorl section is subcircular. There D iscu ssio n : Because of the poor preservation even the exist 15 prorsiradiate ribs of equal size, approximately six ribs identification of the genus is somewhat uncertain. According are present per whorl height. All ribs bear umbilical, lateral to WitL>Mann (1962: 189) and Rlnz (196S: S3) Proturrilitoides and ventral tubercles of variable strength. Of the suture line is regarded only as a subgenus of Turnlitoides SPATH I 923, but nothing is visible. W right (1996: 241) confirms its status as a separate genus as D i sc uss i o n : The specimen is clearly a Uchcaticylus. ft can he did before (Wright 1957: L. 220). Differences between the be distinguished from the closely allied Toxoeeratotdes Spath , two genera are listed in Ki inger & Kennedy (197S: 35), but 1924 by the total lack of nontuberculate intermediate ribs and only the apical angel can be taken into account here, ft is large, from Tonoharmtes Spath , 1924 by the presence of strong which is a characteristic feature of Proturrilitoides (see also tubercles on every rib. A recent list of species attributed to Cooper 1999: 3f.). Only the type species is listed in Ki inger Hclicaneylus is given by A guirrl U rrbta (1986: 284). But due & Kennedy (1978: 39), from which the Tibetan specimen to its fragmentary preservation the Tibetan specimen can not differs clearly in its coarser costulation. Probably it is a new be assigned to one of them.1 * species but too poorly preserved to be described as such.

Plate 4

Fig. I: Submortumceras icnmeustulatum Coii ignon ; Section CA (Zongsh.m Formation, CAÍ 74/1); a: lateral view, b: ventral view; x 2/3. Fig. 2: Colomlneeras (('olmnbncms) cf. subpeltoeeroules Sinzo W; Section A (Ganbadongshan Formation of Gamba Group, Af 71/4); a: lateral view, b: ventral view; x I. Fig. 3: Tnnobanutcs mnltitnbercnlatns n. sp.; \ lolotvpc (Af 71/8); Section A (Ganbadongshan Formation of Gamba Group); a-b: lateral views; x 1. Fig. 4: Tonobamites mitltituberudatus n. sp.; Paratvpe (At 71/5); Section A (Ganbadongshan Formation of Gamba Group), x 1. Fig. 5; Heluamylns sp.; Section A (Ganbadongshan Formation ot Gamba Group, At 71/6); a: ventral view, b: lateral view; x 1. Fig. 6; Toxoceratoidcs atf. rnycruwitm (iPOrbiom); Section A (Ganbadongshan Formation of Gamba Group, Af 71/7); a: lateral view, b; ventral view; x 1. Fig. 7: Donvillciceraspnstnlosnm Casi y; Section A (Chaquiela Formation ot Gamba Group, Af 73A/I); a: ventral view, b: lateral view; x 1. Fig. 8: C/jcAwceR {Chelomccras) aft. bnxtorfi (J \< on, in J At on & Tt mu i<); Section A (Ganbadongshan Formation of Gamba Group, Af 71/1), x I. Fig. LP Parabophtcs trants<.bo!di (Simonovk i i, B.visi-vu n & Sokokjn ); Section A (Ganbadongshan Formation of Gamba Group, Af 71/12); a: ventral view, b: lateral view; x 1. 1 ig. 10: Cbelonuerais {(Jbcloimcms) aft. bnxtorfi (J At t m, in J a * < >R & T< >bi I r);; Section A (Ganbadongshan Formation ot Gamba Group, Af 63/1); a: ventral view, b: lateral view; x I. Fig. I 1: Pambophtes trantstholdi (Simon * >vu m, B mm \ h iu V S orokin ); Section A (Ganbadongshan Formation of Gamba Group, At 71/10); a and c: lateral views, h: ventral view; x 1. Fig. 12: Pambophtes tmutstboldi (Simonovk u , B xtsi viui Sc Sorokin ); Section A (Ganbadongshan Formation of Gamba Group, A1 71/11), x 1. Fig. 13: Proturrilitoides sp.; Section 1 (Chaquiela Pomatum ot Gamba Group, 11 2/1), x 2. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at Zitteliana 23, 2002 Plate 4

Immel & H i: Cretaceous cephalopods of the Tethvan Himalaya of southern Tibet © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 100

Occurrence: The genus Proturnlitoulcs is known from Subfamily Douvilleiceratinae Parona & Bonarelli , 1S97 the Middle Albian of France and Poland. Genus Donvilleicems Dt Grossouvre , 1S94 Type species: Donvilleicemsmammilhtum(S< ttl.oTHEtM, 1S13) Superfamily Douvilleicerataceae Parona & Bonarllli , 1897 Donvilleicems piistnlosnni Casey , 1962 Family Douvilleieeratidae Parona & Bonarelu , 1S97 (PI. 4, Fig. 7) Subfamily Cheloniceratinae Spath , 1923 1962 Donvilleicems pnstnlosnm - Casi y : 2S8; pi. 42, fig. 11; text- lig. 102 g, 1 03 c, d (with svnonymv). Genus Cbeloniccms H yatt , 1903 M a te ria l:/ )ne crushed specimen and three small fragments Subgenus Cbeloniccms (Cbeloniccms) H yatt , 1903 from the base of the Chaquiela Formation of Gamba Group (Section A). Type species: Cb. (Cbeloniccms) cornucliannm (d 'Orbigny , 1841) D escription: The maximum diameter of the most complete specimen was less than 33 mm, no exact measurements can be given. The coiling was nioderately Cbeloniccms (Cbeloniccms) aff. buxtorji involute, the cross section is somewhat depressed with a wide (J acob , in Jai ob & Tobler 1906) shallow external sulcus. The sharp single ribs bear five nodes (PI. 4, Fig. 8, 10) to a row on each side. From the suture line is nothing visible. M aterial: Halt a dozen specimens from a middle part of D isc u ssio n : The specimens are clearly representatives of the Ganbadongshan Formation of Gamba Group (Section A). the genus Douvillciceras because of their shape and The most specimens are cavities in concretions from which tuberculation. This genus has been sphtted extremely. The best casts can be made. correspondence is found with D.pnstnlosnm due to the shallow sulcus and the number of nodes on each rib. D e sc rip tio n : For several specimens exact measurements can be given: It should be noted, that Gl bhard (1983: 126ff.) has proposed D Wh Wb Wh/Wb U to reduce the number of species drastically. Instead of 24 species Af 63/1 35.5 13.5(0.38) 20.5(0.58) 0.66 8.5(0.24) two species should be realistic: D. mammillatum (Schlotheim, Af 71/1 29 12(0.41) 17(0.59) 0.71 8(0.28) 1813) with all ribs and nodes of the same shape and D. Af 71/2 26.5 10(0.38) 15(0.57) 0.67 7(0.26) inaeqmnodum Q uenstedt , 1849 with variable sculpture. An Af 71/3 23.5 9(0.38) 13(0.55) 0.69 7(0.30) equivalent differentiation between this two groups has already been made bv D estombes (1979: 69). In such an extremely The coiling is rather involute, the depressed whorl section reduced system the Tibetan material would belong to D. is at first coronate and subquadrate in a later stage. The simple- ribs are primaries and alternate with one or two intermediaries. mammillatum. There are approximately twenty ribs per half whorl. The Occurrence: D. pnstnlosnm has been described from the primaries bear umbilical and lateral tubercles. The lateral Lower Albian {mammillatum Zone) of southern England. tubercles, in early stages more pronounced, will be reduced later on. Of the suture line nothing is visible. Superfamily Deshavesitaceae Stoyanow , 1949 D iscu ssio n : The specimens belong clearly to the subgenus Famib Parahoplitidae Spath , 1922 Cb. (Cbeloniccms) due to coiling, cross section and sculpture, which lacks ventral tubercles, typical for the subgenus Cb. Subfamily Acanthohoplitinae Stoyanow , 1949 (Epicbelomcems) Casey , 1954. Within the subgenus there is a perfect correspondence in Genus Colombicems Spath , 1923 measurements with Cb. (Cbeloniccms) buxtorfi. The lectotype Subgenus Colombicems (( olombicems) Spath , 1923 of this species - described by Jacob & Tobler (1906: 15; pi. 1, fig. 9) and selected by Casey (1962: 253) - has the following I \ pc species: ( ’. (Colombicems) crassicostatum (d 'Orbigny , measurements: D = 35, Wh = 14(0.40), Wb = 20(0.57), Wh/ 1841) Wb = 0.70, U = 10(0.28). But in the sculpture there is a distinct difference because in the Tibetan material the ribs are more Colombicems (Colombicems) cf. snbpcltoceroidcs dense (20 contrary to 14-15 per half whorl), and the difference Sinzow , 1907 between primaries and intermediaries is more pronounced. Probably the Tibetan material will belong to a new species. (PI. 4, Fig. 2) But we have only inner whorls and these stages are not well M aterial: Two specimens from the Ganbadongshan I ur­ known in some Cbeloniccms. So it seems better to describe ination of Gamba Group (Section A). the specimens in open nomenclature. D e sc rip tio n : The maximum diameter is nearly 55 mm, Occ urren cc: The subgenus Cb. (Cbeloniccms) is a typical the coiling moderately evolute, the flanks flattened and the Upper Aptian form. The Tibetan material is of the same age. external side well rounded. I rom the better preserved specimen © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 101

the measurements will he compared with 'Puruboplites C. (Colombiccrus) is even more similar toPuruboplites but trcflnunus' (A nthui a 1S99: 1 15; pi. 8, Fig. 6) lrom the former may be distinguished bv its sculpture with more heavy, southern USSR (( aucasus), which is a C. (Colombiccrus) accentuate and straight ribs, and also b\ the appearance of subpcltoccroides according to D rushchits & Kudryavtsev strong and elongated umbilical swellings. (I960: 329): D Wh Wb Wh/Wb U Puruboplites truutscboldi Af 71/4 53 20(0.38) 1S.5(0.35) 1.08 1S.5(0.35) (Simonovich , Batm yh h & Sorokin , 1876) "USSR” 45 19(0.42) 19(0.42) 1.12 15(0.33) (PI. 4, Fig. 9, 11, 12) The strong ribs, which are very rapidly widening, start at the umbilical edge simple or branching at elongated swellings. I960 Acuntboboplitcs truutscboldi Sm., B.\< ., Sor. - D rushchits & They cross the flank slightly prorsiradiate or curved and run Kudryavtsev : 322; pi. 10, fig. 1-3 (with synonymy). straight across the external side. Of the suture line nothing is M aterial: Several dozen specimens and fragments can be visible. found, especially as cavities in concretions in the D iscu ssio n : The broad accentuate ribs and the umbilical Ganbadongshan Formation ol Gamba Group (Section A). swellings are characteristics of the subgenus C. ( Colombiccrus), D e s c rip tio n : The coiling is quite involute, the whorl the distinguishing feature to the subgenus Colombiccrus height increases moderately rapid. The section is compressed (Egoiunicerus) A VRAM, 1974 is the presence of tubercles, also with slightly convergent sides and broadly arched venter. From contrasting to Puruboplites Anthula , 1899, which is a very the most complete specimens the following measurements can closely allied genus (see there). be given. They will be compared with a specimen from the Within C. (Colombiccrus) the best correspondence is with former southern USSR, described bv G lazunova (1953: 45, C. (C.) subpcltoccroidcs, although there are some minor see also pi. 8, fig. 5): differences in measurements (see above) and ribbing. But as D Wh Wb Wh/W b U nearly nothing is known about the variability of C. (C.) 'USSR' 51 22.2(0.43) 18.7(0.36) 1.19 13.2(0.26) subpeltoceroides, only an approximative identification of the Af 71/11 38 15.5(0.41) -13(0.34) 1.19 1 1.5(0.30) Tibetan material seems possible. Af 71/12 38 14.5(0.35) 12.5(0.33) 1.16 11 (0.29) O ccu rrence: The species C.(C.)subpeltoceroides is known Af 71/10 35 14(0.40) 12(0.34) 1.17 9.5(0.27) from the Upper Aptian of the former southern USSR. Af 71/9 34 14(0.41) 12(0.35) 1.17 9.5(0.2S) Af 70/1 26 10(0.39) 8.5(0.32) 1.18 7(0.27) The ribs, first branching near the umbilical wall later alterna­ Subfamily Parahoplitinac Si vth, 1922 tively' longer and shorter ones, are somewhat sinuous on the Genus Puruboplites A nthula , 1 899 flanks. They thicken rapidly and cross straight the venter without building any tubercles. Of the suture line mostly not­ Type species: Puruboplites melcbioris A nthula , 1899 hing is visible. Puruboplites is one of the most common genera. Although D is c u s s io n : Coiling and cross section as well as the there is a broad variability presumably all specimens can be complete absence of any tubercles show that the specimens assigned to one species. belong to the genus Puruboplites. Within this genus the rapid The greatest problem is the determination of the genus, thickening of the ribs as well as their straight crossing of the because there is no general agreement about the diagnosis of external side is unusual. But exact in this details and also in the Puruboplites, Acuntboboplitcs SlNZOY, 1907 or Colombiccrus measurements, there is a perfect correspondence with P. Spath , 1923. The type species of all this genera were united by truutscboldi, described and figured from the former southern A nthula (1899: 110) in his new genus Puruboplites. So it is USSR by Glazunova (1953). Gi azun < >va assigned this species necessary to clarify the diagnostic features of the genera: to Acuntboboplitcs, as D rushchits & Kudrya \tsfy (1960: 322) Puruboplites is characterized - as the whole subfamily - 'by did it later. But P. truutscboldi lacks anv tubercles, as already the absence of tubercles at all stages of growth' (C ASIA' 1965: described bv Simonovich et al. (IS76: 101), so it can not be an 400). Acuntboboplitcs.

Acunthoboplites is distinguished from Puruboplites due to Occurrence: P. truutscboldi has been described till now its prominent lateral tubercles, where the ribs are branching only from the lower Upper Aptian of the former southern on the inner whorls. USSR (noluni Zone). © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at

1 0 2 4. PALAEOBIOGEOGRAPHIC ASPECTS

The palaeobiogeographic situ.itn.rn ot Central and South Asia the late Cretaceous vertebrate fauna of India. This fauna can during the Cretaceous has been discussed highly controversal he compared whith Eurasian forms and is lacking endemisms. for a long time, bar example, as far as India is concerned, there This would be inconsistent with a long isolation of the Indian is much disagreement as to when it has rifted off Gondwana plate (see also CiiATTtRjH- 1985). and collided with Asia. Generally, a late separation in a southern position is assumed and also a late collision in the With regard to South Tibet, the Tethvan Himalaya is early Eocene (e.g. Gumbos et al. 1995: l-'ig. 3). This view has generally considered to represent the northern shelf of the recently been confirmed by Bardhan ct al. (2002) based on an Indian plate. Therefore the same dehate is going on. For ammonite fauna from Coniaeian horizons in Bagh, central example, the bivalve fauna of the Gamba Group clearly India, indicating close affinities to coeval horizons of indicates a southern position during the Aptian and Albian Madagascar and Zululand, South Africa. Contrary to this view, and remained in 'relation and exchange with that of Antarctica- however, J\t(,l-R et al. (1989) proposed a more northern Australia in spite of its strong local colour'(W i-.n 2000: 5). position of India and an earlier contact with Asia according to Contrary, the Cretaceous corals of Tibet, analysed by Losfr

L A North Temperate Realm (Boreal Realm) Cl Central Iran B Tethyan Realm L L u t block C South Temperate Realm F Farah block . ,7 ' Hoplitinid Faunal Province H Helmand block 1 Kolah-Qazi mountains (Central Iran) NT North Tibet 2 Gamba region (Tethyan Himalaya) ST South Tibet

lug. l>: Simplified middle Cretaceous palaengeographv (modified alter Smii'H et al. I9XI: map 25) and pulneo- hiogeographu realms (after Kal i i MAN 1V73: fig. 2). Also shown are some microplates ot the Middle and Far Fast and the outline ol ail extended hoplitinid faunal province. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 103

¡3; Liao (2001) have their closest relationships with Tethvan Group. This genus is restricted to the boreal realm too. tn more

faunas from Western L.urope to Asia, despite of a great number detail, Paraboplitcs trautsiholdt, hitherto known only from the of endemisms. former southern USSR w as found now in Gamba. On one side, the ammonites described ill this paper show in conclusion the hoplitinid faunal province is considered some affinities to those of southern tndia, Madagascar, and to expand as tar to the southeast as to include the Gamba area South Africa - i.e. to the southern temperate realm as defined (see figure 9, point 2). This result complements the extension b\ KAIM-MAN (1973). This is confirmed bv sev eral genera and first suggested b \ Immil be S i m h -E mami (19S5). They species from the Gamba area (l.cmiiroicras, Goodhallitvs ct. documented that the ammonite fauna of the glauconitic gracillimum) and from the Zala valley of the Duela area limestone of the Kolah-Qa/i-mountains (Central Iran) also [Mortoniccras (Dcirailoccras) bnpinosum, Gooilbdlhtcs belonged to the boreal hoplitinid province in middle proccnon]. Cretaceous times (sec figure 9, point 1). Chi the other side, however, the ammonoid fauna has also a However, there is a considerable difficulty if these two strong affinity to the northern temperate realm (boreal realm), regions were added to the hoplitinid faunal province. The especially to the hophtinid faunal province, first introduced Kolah-Qazi-mountains are situated on a well defined bv Ow en (1971) and lateron cited and retigured by Jlk .ni I be microplate. Central Iran, tn contrast, the Tethvan Himalaya, Ki \siim (1976: fig. 20). According to these authors this faunal including the Gamba area, is generally considered to be part province ranges from southwestern England to the eastern of the northern edge of the Indian plate (see above), which is border of the Caspian Sea. Significant amnaonoids of this usually taken to be situated tar more to the south in middle province, the LTpper Album genera Callibuphtcs, Plcurubophtcs Cretaceous times (see Figure 9). One possibility to solve this and Cyunihoplites, all occur in the Gamba Group. A boreal problem would be to postulate that the Tethvan Himalaya was influence is also documented in the L'pper Aptian bv part of a separate microplate as well, as suggested bv Sinha - Parabophtcs, one of the most common genera in the Gamba Ri o ((976) orS rikantia ( I9S7).

5. SUMMARY

This paper deals with the Cretaceous cephalopods from the others are ammonites. Among the ammonites three new species Tethvan Himalaya of southern Tibet (Gamba and Duela area). are established: Plcurubophtcs (Plcinobophtcs) robasticostatns, Following a short review of previous studies the authors / enutmeeras tibctiann, and Pimohamites nuiltitiiberciiLitiis. discuss three aspects in more detail.

5.3 PALAEOBiOGEOGRAPHY 5.1 GEOLOGY The ammonites of the middle Cretaceous of the Tethvan The cephalopod fauna of eight sections and sampling points, 1 limalava display a mixed biogeographic pattern. Some genera respectively, is listed and then stratigraphic age is indicated, tt and species - as for example Lmmroccras - are known only ranges from Neocomian to Maastrichtian, with a concentration from the southern temperate realm. But more genera exist that in the middle Cretaceous (Aptian - Cenomanian). are characteristic for the hoplitinid faunal province of the At one section (A) the stratigraphic results are used to northern temperate (boreal) realm: m the Upper Aptian reconstruct the tectonic disruption of the Gamba Group. Pdr.tboplitcs, in the Lower Albian Cymabnplitcs, and in the Upper Albian Cdlliboplitcs as well as Plcitroljoplitcs. Therefore it is suggested that the Gamba area of southern Tibet was part 5.2 SYSTEMATiCS of an extended hoplitinid faunal province and that in middle Twenty-nine cephalopod genera and species are described Cretaceous tunes the geographic position of the Tethvan in detail and are figured. Two taxa belong to the nautilids, all 1 limalava of southern Tibet was far more to the north. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zobodat.at 104 6. REFERENCES

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Manuscript received October 2002.