new mastodonsaurid temnospondyls from the cynognathus assemblage zone...

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NEW MASTODONSAURID TEMNOSPONDYLS FROM THE CYNOGNATHUSASSEMBLAGE ZONE (UPPER BEAUFORT GROUP KAROO BASIN) OFSOUTH AFRICAAuthor(s) ROSS J DAMIANI and P JOHN HANCOXSource Journal of Vertebrate Paleontology 23(1)54-66 2003Published By The Society of Vertebrate PaleontologyDOI httpdxdoiorg1016710272-4634(2003)23[54NMTFTC]20CO2URL httpwwwbiooneorgdoifull1016710272-463428200329235B543ANMTFTC5D20CO3B2

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54

Journal of Vertebrate Paleontology 23(1)54ndash66 March 2003q 2003 by the Society of Vertebrate Paleontology

NEW MASTODONSAURID TEMNOSPONDYLS FROM THE CYNOGNATHUS ASSEMBLAGEZONE (UPPER BEAUFORT GROUP KAROO BASIN) OF SOUTH AFRICA

ROSS J DAMIANI1 and P JOHN HANCOX2

1Bernard Price Institute for Palaeontological Research University of the Witwatersrand Private Bag 3 Wits 2050South Africa damianirgeoscienceswitsacza

2Department of Geology University of the Witwatersrand Private Bag 3 Wits 2050 South Africa

ABSTRACTmdashTwo new mastodonsaurid temnospondyls are described from the Early to Middle Triassic CynognathusAssemblage Zone of the Upper Beaufort Group (Karoo Basin) of South Africa Paracyclotosaurus morganorum spnov is based on a partial skull from the uppermost part of the Cynognathus Assemblage Zone (Subzone C lateAnisian) in the southern Karoo Basin and is the first occurrence of the genus Paracyclotosaurus outside of India andAustralia Jammerbergia formops gen et sp nov is based on a partial skull presumably from Subzone B (earlyAnisian) of the Cynognathus Assemblage Zone and is distinctive in its unique suite of primitive and derived charactersAlthough the intrarelationships of mastodonsaurids remain largely unresolved the two most recent analyses are similarin the identification of an lsquoadvancedrsquo mastodonsaurid clade whose members are characterized by laterally directedtabular horns Jammerbergia probably belongs within this clade albeit within a basal position Jammerbergia andParacyclotosaurus share the synapomorphy of large antero-posteriorly expanded tabulars and may represent sistertaxa The Cynognathus Assemblage Zone is characterized by three subzones of differing ages and faunas with nooverlap in the temnospondyls between the subzones

INTRODUCTION

Temnospondyls form an important part of the fauna of thePermo-Triassic Beaufort Group of the Karoo Basin of SouthAfrica but have tended to be neglected in favor of studies ontherapsids which form the basis for the eight-fold biostrati-graphic subdivision of the Beaufort Group (Rubidge 1995)Recently there has been a resurgence in studies of BeaufortGroup temnospondyls including taxonomic descriptions of newspecies (Shishkin et al 1996 Warren 1999 Damiani andKitching 2003) descriptions of new material of existing spe-cies (Shishkin and Welman 1994 Damiani 2001a) and taxo-nomic reassessments of older material (Warren 1998 Latimer1998) Compared with other Beaufort Group biozones the Earlyto Middle Triassic Cynognathus Assemblage Zone (Fig 1) hasan abundance of temnospondyl material The main temnospon-dyl representatives within this biozone are the Mastodonsauri-dae the senior synonym of the better known Capitosauridae(Damiani 2001b) and are represented by the following diag-nostic taxa Watsonisuchus magnus (Watson 1962 Damiani2001b) Parotosuchus haughtoni (Broili and Schroder 1937Damiani 2001a) Wellesaurus africanus (Broom 1909 Dami-ani 2001b) Rarer temnospondyl components of the Cynogna-thus Assemblage Zone include the Trematosauridae Brachyop-idae Rhytidosteidae and Laidleriidae The Laidleriidae arehowever known from only a single specimen Laidleria gracilis(Kitching 1958 Warren 1998) which is questionably from theunderlying Lystrosaurus Assemblage Zone (Kitching perscomm)

During recent fieldwork by the junior author in the Bam-boeshoek Valley of the Eastern Cape Province a new tetrapodfaunal assemblage was discovered in the southern Karoo BasinThis new fauna contains the cynodont therapsid Cynognathusand may therefore be broadly assigned to the Cynognathus As-semblage Zone The fauna also contains at least two dicynodontgenera previously unknown from the biozone as well as a newmastodonsaurid recently reported by Hancox et al (2000) torepresent a new species of the genus Paracyclotosaurus a tax-on previously known only from the Middle Triassic of Australia

(P davidi Watson 1958) but recently shown (Damiani 2001b)to also include a newly described Indian species (lsquoParotosu-chusrsquo crookshanki Mukherjee and Sengupta 1998) This newspecies is fully described below In addition during a recentinspection by the senior author of the temnospondyl collectionof the National Museum Bloemfontein a large previously un-described mastodonsaurid was found This specimen apparent-ly from the Cynognathus Assemblage Zone represents a newgenus and species and is described below

The aim of this paper is to fully describe the new mastodon-saurid material and to compare it with other mastodonsauridsincluding in particular those from the Cynognathus AssemblageZone of South Africa The increasingly important role that tem-nospondylsmdashand mastodonsauroids in particularmdashare playingin biostratigraphy and correlation of Triassic terrestrial tetrapodfaunas both locally (Hancox et al 1995 Shishkin et al 1995Hancox and Rubidge 1997) and globally (Ochev and Shishkin1989 Shubin and Sues 1991 Lucas 1998) underscores theimportance of documenting and accurately describing new tem-nospondyl material from the Triassic

Age of the Cynognathus Assemblage Zone

Despite the abundance of both therapsid and temnospondylmaterial in the Cynognathus Assemblage Zone its age has beenmuch debated It has variously been considered Early Triassic(DuToit 1954 Cosgriff 1965 Anderson and Anderson 1970Chernin 1978) late Early Triassic (Anderson and Cruickshank1978 Cosgriff 1984 Battail 1988 1993) or Middle Triassic(Huene 1940 Kitching 1977 Cruickshank 1986 Ochev andShishkin 1989 Shubin and Sues 1991 Shishkin and Ochev1994) Recently Lucas (1998) made the Cynognathus Assem-blage Zone the type assemblage for his Nonesian LVF (LandVertebrate Faunachron) of Olenekian age In marked contrastCooper (1982) assigned the biozone a Late Permian to EarlyTriassic age while the lexicon of South African stratigraphy(Johnson 1994) assigns the Burgersdorp Formation the strati-graphical unit encompassing the Cynognathus AssemblageZone a Permian age Finally Groenewald (1996) assigned the

55DAMIANI AND HANCOXmdashNEW MASTODONSAURIDS FROM SOUTH AFRICA

FIGURE 1 Map of South Africa showing the spatial distribution ofthe Cynognathus Assemblage Zone (shaded area) and the type localities(stars) for Paracyclotosaurus morganorum sp nov (Wilgerkloof) andJammerbergia formops gen et sp nov (Jammerberg) with the Beau-fort Group outlined Dashed lines indicate uncertain biozone boundar-ies Map after Rubidge (1995)

Tarkastad Subgroup of which the Burgersdorp Formation is theuppermost unit an age ranging from Early to Late Triassicthereby assigning the Burgersdorp Formation a Late Triassicage

Temnospondyls have played an important role in the datingof the Cynognathus Assemblage Zone On the basis of his de-scription of the mastodonsaurid lsquoCyclotosaurusrsquo albertyniBroom (1904) proposed a Late Triassic age for the CynognathusAssemblage Zone Much later Cosgriff (1965) assigned the bio-zone an Early Triassic age based on the similarity between therhytidosteids Rhytidosteus (Owen 1884) from South Africa andDeltasaurus (Cosgriff 1965) from the Blina Shale of WesternAustralia Most subsequent age estimations by temnospondylworkers have been based on the supposed presence in the Cy-nognathus Assemblage Zone of the well-known Early Triassicmastodonsaurid Parotosuchus However recent stratigraphicwork combined with new fossil discoveries in the CynognathusAssemblage Zone have allowed a re-evaluation of the age ofthe biozone (Hancox et al 1995 Shishkin et al 1995 Hancoxand Rubidge 1997 Hancox 1998) Hancox et al (1995) pro-posed a threefold subdivision of the Cynognathus AssemblageZone based primarily on the spatial and temporal distributionof mastodonsaurids within the biozone as well their associatedtetrapod faunas The lowest subzone (A) had as its index fossilthe poorly known Parotosuchus-like mastodonsaurid lsquoKestro-saurusrsquo (Haughton 1925 an indeterminate mastodonsaurid ac-cording to Damiani 2001b) and was thus correlated with theUpper Olenekian Parotosuchus fauna of eastern Europe (Ochevand Shishkin 1989) The middle subzone (B) contains the morederived mastodonsaurid Wellesaurus africanus (Broom 1909)and was assigned an Anisian age Finally the upper subzone(C) had as its index fossil lsquolsquoadvanced capitosauroid amphibi-ansrsquorsquo comparable to Eryosuchus pronus (Howie 1970 Dami-ani 2001b) from the Middle Triassic of East Africa and wasalso assigned an Anisian age Thus the Cynognathus Assem-blage Zone was thought to extend across the EarlyndashMiddle Tri-assic boundary The subsequent discovery of Parotosuchus sen-

su stricto (Damiani 1999) in a locality assignable to SubzoneA and referral of the lsquolsquoadvanced capitosauroidrsquorsquo material ofSubzone C to Paracyclotosaurus (Hancox et al 2000 this pa-per) has supported this age assignment The age of the secondnew mastodonsaurid described in this paper is discussed later

Institutional Abbreviations BP Bernard Price Institutefor Palaeontological Research Johannesburg GHG Councilfor Geoscience Pretoria NM National Museum Bloemfon-tein SAM South African Museum Cape Town UMZC Uni-versity Museum of Zoology Cambridge

Anatomical Abbreviations al alar process of the jugalapqf accessory paraquadrate foramen b lsquobossrsquo on tabular cmcrista muscularis cmp crista muscularis of the parasphenoidcp cultriform process of the parasphenoid ct crista terminaliscte crista tabularis externa cty crista tympanica ec ectopter-ygoid eo exoccipital f frontal fc falciform crest fm fora-men magnum groove groove on paroccipital process iv in-terpterygoid vacuity j jugal js jugal sulcus mx maxilla oroblique ridge of the pterygoid p parietal pi pineal pf pre-frontal po postorbital pof postfrontal pp postparietal pqfparaquadrate foramen ps parasphenoid psm processus sub-medullaris pt pterygoid ptf post-temporal fenestra q quad-rate qj quadratojugal s stapes sof supraoccipital foramensos supraoccipital sulcus sq squamosal st supratemporal svsubtemporal vacuity t tabular ts temporal sulcus XII fora-men for cranial nerve twelve

SYSTEMATIC PALEONTOLOGY

TEMNOSPONDYLI Zittel 1887ndash1890 sensu Laurin (1998)STEREOSPONDYLI Zittel 1887ndash1890 sensu Yates and

Warren (2000)MASTODONSAUROIDEA Lydekker 1885 sensu Damiani

(2001b)MASTODONSAURIDAE Lydekker 1885 sensu Damiani

(2001b)PARACYCLOTOSAURUS Watson 1958

Type Species Paracyclotosaurus davidi Watson 1958Referred Species P davidi Watson 1958 P crookshanki

Mukherjee and Sengupta (Damiani 2001b) P morganorumsp nov

Distribution Paracyclotosaurus is known from the MiddleTriassic of Australia (P davidi) India (P crookshanki) andSouth Africa (P morganorum sp nov) and thus appears en-demic to Gondwana

Emended Diagnosis Distinguished from all other masto-donsaurids by the following combination of apomorphic char-acters tabulars large expanded antero-posteriorly tabularhorns laterally directed and possessing antero-distal lsquolappetrsquosquamosalquadratojugal margin of skull level with posteriormargin of skull deck basicranium elongated ventral exoccipi-tal-pterygoid contact present ventral lsquobulgersquo present at junctionbetween exoccipital and pterygoid cultriform process of par-asphenoid lsquokeeledrsquo ventrally exoccipital condyles situated levelwith quadrate condyles choanae narrow slit-like

PARACYCLOTOSAURUS MORGANORUM sp nov(Figs 2ndash4)

Paracyclotosaurus morgani Hancox and Rubidge 1997 nomennudum

Paracyclotosaurus morgani Hancox 2000 nomen nudum

Holotype BP15551 the right posterior portion of a skullexcluding the quadratojugal

Locality and Horizon Farm Wilgerkloof Sterkstroom Dis-trict Eastern Cape Province South Africa (Fig 1) Upper Bur-

56 JOURNAL OF VERTEBRATE PALEONTOLOGY VOL 23 NO 1 2003

FIGURE 2 Photographs of skull of Paracyclotosaurus morganorum sp nov (BP15551) in A dorsal B ventral and C occipital views Scalebar equals 5 cm

gersdorp Formation Cynognathus Assemblage Zone (SubzoneC of Hancox et al 1995) late Anisian (Hancox et al 2000)

Etymology Named after the Morgan family of the Bam-boeshoek Valley Eastern Cape Province for invaluable assis-tance with fieldwork which culminated in the discovery of BP15551

Diagnosis A species of Paracyclotosaurus distinguishedfrom P davidi and P crookshanki by the following autapo-morphies foramen basis cranii (new term) present exception-ally long subotic process of exoccipital exoccipital condyleslsquostalkedrsquo

DESCRIPTION

Preservation

The material consists of a large well preserved although in-complete skull preserved in a grey fine-grained sandstone ma-

trix The skull was found broken into three separate blockswhich were joined together with Glyptal Subsequent prepara-tion was undertaken mainly by mechanical means as the matrixdid not respond to acid treatment Matrix has been cleared frommost of the occiput and left subtemporal vacuity but not fromthe interpterygoid vacuities Teeth on the right maxilla and ec-topterygoid are visible but for the most part remain embeddedin matrix A single displaced tooth is preserved in the matrixof the right interpterygoid vacuity and another on its side onthe right ectopterygoid The skull has suffered some post-mor-tem compaction posteriorly evident in occipital view Compac-tion in this area has pushed down the tabular and dislodged theexoccipital from its contact with the postparietal This crushinghas rendered the occiput difficult to interpret although a ten-tative restoration of the occiput has been made in an attempt tocorrect for this There is othwerwise little evidence of distortionof the skull The preserved part of the skull is complete except


FIGURE 3 Interpretive drawings of skull of Paracyclotosaurus morganorum sp nov (BP15551) in A dorsal B ventral and C occipitalviews Except for within the orbit and pineal areas not shaded represent broken bone Dense stippling represents matrix Scale bar equals 5 cm

for sections of the right jugal squamosal quadratojugal and asmall section of the tabular horn on the skull roof and sectionsof the maxilla ectopterygoid quadrate and quadratojugal onthe palate

Skull Roof

The skull roof (Figs 2A 3A 4A) of Paracyclotosaurus mor-ganorum displays a flattened snout with a slight preorbital stepjust anterior to the orbits In Paracyclotosaurus davidi the skullhas suffered obvious compaction (Damiani pers obs) so thatthe presence of a preorbital step cannot be determined Thepresence of a preorbital step has not been well documented inmastodonsaurids but appears to be a feature of more basal EarlyTriassic taxa such as Parotosuchus Wetlugasaurus and Wat-sonisuchus The preserved right orbit is only slightly lsquoraisedrsquoabove the level of the surrounding skull roof so that the troughformed between the orbits is only moderately deep The orbit

is oval shaped and its long axis is directed towards the midlineof the skull As in P davidi (Watson 1958) and Paracycloto-saurus crookshanki (Mukherjee and Sengupta 1998) the squa-mosalquadratojugal margin of the skull posteriorly is posi-tioned anterior to the lsquohornrsquo of the tabular In contrast in otherMiddle Triassic mastodonsaurids in which the tabular horns areposterolaterally directed such as Eryosuchus pronus (Howie1970) or Tatrasuchus wildi (Schoch 1997 Damiani 2001b)the same margin is located posterior to the lsquohornrsquo of the tabularThe occipital condyles are visible dorsally as in P crookshankiand P davidi (Damiani pers obs)

Ornament on the skull roof is well developed and consistsof large but irregularly shaped pits up to 2 mm in depth sep-arated from adjacent pits by narrow ridges up to one millimetrein width A ridge-groove type of ornament is present on thefrontals prefrontals jugal and squamosal in the usual masto-donsaurid fashion


FIGURE 4 Reconstructed outline of skull of Paracyclotosaurus morganorum sp nov (BP15551) in A dorsal B ventral and C occipitalviews The occipital reconstruction is necessarily tentative because of compaction in that area Scale bar equals 5 cm

The sensory canal system consists of irregularly shaped pitswhich form chains rather than canals in the proper sense Thesepits are of the same general structure as those of the dermalornament and are consequently virtually indistinguishable fromthe surrounding ornament Nevertheless sections of the rightand left supraorbital and the right temporal sulcus can be dis-cerned under oblique lighting

The dermal bone of the skull roof varies in thickness from 5mm to 10 mm Individual bones are sutured to one another forthe most part by simple planar surfaces with little interdigita-tion and ornament appears to stop short at most of the suturaljunctions The arrangement of skull roofing bones is typical ofthat of mastodonsaurids and only a few points will be men-tioned here As in all mastodonsaurids except Wetlugasaurus(Sennikov 1981) and some specimens of Cyclotosaurus (Kam-phausen 1994) and Benthosuchus (Bystrow and Efremov1940) the frontal bone enters the orbital margin The suturalmargins of the right postorbital could not be traced fully al-though the postorbital was clearly lsquohookedrsquo around the postero-lateral margin of the orbit as is usual for mastodonsaurids in-cluding Mastodonsaurus (Schoch 1999 contra Damiani

2001b) As a consequence of the anterolateral expansion of thepostorbital the jugal forms only a thin wedge of bone betweenthe prefrontal and the postorbital on the lateral margins of theorbit The preserved right tabular horn is complete except fora portion of the tip which gives the horn the appearance ofnarrowing distally However when restored (Fig 4A) the hornis evidently broad throughout its length as in P davidi (Wat-son 1958) and P crookshanki (Mukherjee and Sengupta1998) and as in those species a lsquolappetrsquo is present on theantero-distal margin of the horn A similar lsquolappetrsquo is presentin E pronus (Howie 1970) but the tabular in that species isunexpanded antero-posteriorly In Wellesaurus africanus (Cher-nin 1978 Damiani pers obs) the tabular horn is unexpandedantero-posteriorly and lacks a distal lsquolappetrsquo and closely resem-bles that of Wellesaurus peabodyi (Welles and Cosgriff 1965)

Palate

As with the palates of Paracyclotosaurus davidi (Watson1958) and Paracyclotosaurus crookshanki (Mukherjee and Sen-gupta 1998) the palate (Figs 2B 3B 4B) of Paracyclotosau-


rus morganorum is derived particularly in the basicranial re-gion The basicranium itself is markedly more elongated thanthat of Eryosuchus pronus (Howie 1970) Cherninia megarhina(Damiani 2001c) and Wellesaurus africanus (Chernin 1978)the three other Middle Triassic mastodonsaurids from AfricaEven in large specimens of W africanus (GHG R487 unpub-lished information) with a midline length of 50 cm the basi-cranial region remains relatively short The corpus of the par-asphenoid which forms the centre of the basicranium broadensposteriorly where it accommodates a weak transversely orient-ed ridge the crista muscularis of the parasphenoid This ridgemerges with the surface of the bone both laterally and appar-ently medially and may not have been continuous with thecorresponding left half of the ridge Interestingly a discontin-uous crista muscularis of the parasphenoid was also figured forP davidi (Watson 1958) but the area was not well preservedin that species or in P crookshanki Anteriorly the parasphenoidis continued by the cultriform process The cultriform processis uniformly wide along its length and flat in its most posteriorportion further anteriorly the cultriform process deepens andforms a lsquoknife-edgedrsquo keel An identical keel is present on Pcrookshanki but the area was not preserved in P davidi Themost extraordinary aspect of the basicranium is the presence ofa large foramen or canal formed by the corpus of the paras-phenoid and the neck of the exoccipital here termed the fora-men basis cranii An identical though smaller foramen is pre-sent in both juvenile and adult skulls of the basal mastodon-saurid Watsonisuchus aliciae (Warren and Hutchinson 1988Warren and Schroeder 1995) as well as in a specimen of Epronus (Damiani pers obs of UMZC T289 paratype of Howie(1970)) The foramen basis cranii is continuous with the floorof the parasphenoid dorsally and may have represented an exitpassage for a ventral exposure of the cartilaginous basioccipital

The exoccipital of P morganorum is lsquostalkedrsquo so that thecondylar facet is separated from the body of the parasphenoidby a distinct lsquoneckrsquo In contrast in P davidi and P crookshankithe condylar facets are positioned close to the posterior borderof the parasphenoid In addition the subotic process of the ex-occipital in P morganorum is considerably more elongated an-teriorly than in the two other species As in most post-EarlyTriassic mastodonsaurids a ventral exoccipital-pterygoid con-tact is present as is the peculiar triangular bulge where thesebones meet ventrally The presence of this bulge is not howeverrestricted to those taxa in which a ventral exoccipital-pterygoidcontact is present as demonstrated by the second new taxondescribed below The exoccipital condyles lie at the same trans-verse level as the quadrate condyles whereas in E pronus andW africanus the exoccipital condyles lie well anterior to thequadrate condyles The quadrate shows the L-shaped configu-ration typical of mastodonsaurids but appears to lack a well-developed lsquobossrsquo or hyoid tubercle on its medial margin

The pterygoid consists of a main body a palatal ramus anda quadrate ramus The quadrate ramus of the pterygoid is some-what longer than might be expected in a derived Middle Tri-assic mastodonsaurid as it appears to have a prolonged contactwith the medial margin of the quadrate The medial margin ofthe quadrate ramus is slightly convex rather than straight whenviewed ventrally a feature which may be characteristic of morederived mastodonsaurids Its dorsal margin gives rise to a tallcrest-like oblique ridge that is visible ventrally The palatal ra-mus of the pterygoid bears a strong transverse flange and islightly sculptured with shallow grooves along its outer marginThis light sculpturing continues onto the ectopterygoid

The ventral surface of the preserved right tabular horn bearsa series of muscular ridges characteristic of mastodonsauridsThe most prominent is the crista tabularis externa which runsalong the ventral surface of the tabular portion of the paroccip-ital process and terminates at the tip of the tabular horn The

crista terminalis forms a low ridge a little anterior and obliqueto the crista tabularis externa A third ridge the crista tympan-ica is in P morganorum obscured by matrix but normallyforms a low ridge bordering the tabular rim of the otic notchventrally

Teeth on the preserved portions of the maxilla and ectopter-ygoid are embedded in matrix and have been broken towardsthe tips but appear to have been transversely compressed to-wards the base This is the typical derived condition for mas-todonsauroids (Damiani 2001b) In addition there is a reduc-tion in tooth size on the maxilla from anterior to posterior thisreduction is less marked on the ectopterygoid A single dis-lodged tooth on the ectopterygoid shows that the teeth wereslightly recurved medially

Occiput (Figs 2C 3C 4C)

As mentioned earlier the occiput of Paracyclotosaurus mor-ganorum has suffered post-mortem compaction rendering dif-ficult the interpretation of this region as well as comparisonswith the occiputs of P davidi and P crookshanki Furthermoresutural contacts between the various bones could not be tracedaccurately although vague outlines of individual bones can bediscerned The occiput of P morganorum appears to have beenmoderately shallow while the curvature of the cheek regioncannot be determined accurately because of incomplete pres-ervation in this area

The occipital face of the pterygoid consists largely of theoblique ridge which rises rapidly from a point close to themedial margin of the pterygoid and forms a tall crest-like ridgethe upper margin of which lies just below the otic notch Theupper part of the wall of the oblique ridge is gently concave sothat it curves away from the ascending ramus of the pterygoiddorsally The posteriormost portion of the oblique ridge hassuffered some damaged but is otherwise undistorted The as-cending ramus of the pterygoid is completely obscured by ma-trix

The crista falciformis on the occipital margin of the squa-mosal forms a well developed flange which overhangs the squa-mosal by some 20 mm and nearly contacts the distal end of thetabular horn Below this the descending or occipital flange ofthe squamosal is largely covered by a thin layer of matrix butappears to have been quite short

The occipital aspect of the tabular is remarkably elaboratebearing ridges and grooves that are visible both in occipital andventral view (Fig 3B C) Although the suture between theexoccipital and the tabular on the paroccipital process could notbe fully traced most of this process was probably formed bythe tabular as in other mastodonsaurids The paroccipital pro-cess bears a long crista muscularis ventrally which is continu-ous distally with the crista tabularis externa of the tabular hornProximally the paroccipital process bears a deep groove some20 mm in length along its ventral border Whether this grooveis real or a taphonomic artefact cannot be determined becauseof the compaction of the occiput A deep crista muscularis onthe occipital margin of the tabular dorsally overhangs and formsthe upper border of the posttemporal fenestra At the pointabove where the paroccipital process meets the horn of the tab-ular the crista muscularis forms an elliptical lsquobossrsquo A similarlsquobossrsquo appears to be present in Cherninia denwai (Mukherjeeand Sengupta 1998 Damiani 2001b)

Unfortunately the occiputs of both P davidi and P crook-shanki have not been adequately described It should be notedthat the figure captions for figures three and six in Mukherjeeand Senguptarsquos (1998) paper had been inadvertently transposedso that figure three of that paper actually shows the occiput ofP crookshanki and not C denwai Phenetically the occiput ofP morganorum does not appear to differ significantly from that


of P crookshanki Both are moderately shallow have stronglydeveloped oblique ridges lack any development of a spina su-praoccipitalis (Bystrow and Efremov 1940) and share a slight-ly convex quadrate ramus of the pterygoid In addition theparoccipital process of the tabular in P crookshanki appears tobe endowed with the ridges and grooves present in P morga-norum the exception being the absence of a lsquobossrsquo on the oc-cipital margin of the tabular The orientation of the exoccipitalcondylar facets also appears to differ but this may have beenaffected by compaction

Stapes

The stapes is preserved in situ but its dorsal and lateral sur-faces are largely obscured by matrix which proved inaccessibleThus the shaft can only be seen in ventral view (Fig 3B) Thestapes is typically mastodonsaurid in being slender and rod-likemeasuring some 70 mm in length and between 7 mm and 8mm in width along the shaft The shaft appears to have beenmoderately compressed dorso-ventrally is a little curved dor-sally and bears a weak longitudinal rounded ridge postero-ventrally The presence or absence of a stapedial foramen couldnot be determined because of damage to the surface of thestapes Little detail of the stapedial footplate or of its articula-tion can be observed

The orientation of the stapedial shaft follows that of othermastodonsaurids (Warren and Schroeder 1995 Schoch 2000aDamiani 2001a) in that it is directed dorso-laterally with the tipof the shaft pointing into the postero-medial corner of the oticnotch (Fig 3A) Distally the anterior edge of the shaft passesabove the oblique ridge of the pterygoid but does not cross itThere is no indication of any sutural attachment to either theparoccipital process the tabular or the oblique ridge and theshaft was evidently lsquofreersquo within the middle ear cavity in asituation similar to that of anurans (Schoch 2000a)

JAMMERBERGIA gen nov

Etymology After Jammerberg Afrikaans for lsquoSorry Moun-tainrsquo the type locality

Type Species Jammerbergia formops sp novDiagnosis Distinguished from all other mastodonsaurids by

the following combination of apomorphic characters tabularslarge expanded antero-posteriorly tabular horns laterally di-rected squamosalquadratojugal margin of skull foreshortenedquadrate ramus of pterygoid short ventral lsquobulgersquo present onlateral margins of body of parasphenoid exoccipital condylessituated level with quadrate condyles large medial process ofquadratojugal which contacts the quadrate ramus of the ptery-goid crista muscularis of paroccipital process massive One au-tapomorphic character is present occipital border of the skulldeck posterior to the squamosalqudratojugal margin of theskull roof

JAMMERBERGIA FORMOPS gen et sp nov(Figs 5ndash7)

Holotype NM QR1436 a partial skull without mandiblescollected by E C N van Hoepen then Director of the NationalMuseum Bloemfontein in 1927

Locality and Horizon Jammerberg Wepener District FreeState Province South Africa (Fig 1) Subzone B Cynogna-thus Assemblage Zone early Anisian (Hancox and Rubidge1997 Hancox 1998) Unfortunately the stratigraphic and bio-stratigraphic placement of J mucidiops within the CynognathusAssemblage Zone is uncertain as there were no other details ofits collection As far as can be determined the only other fossilsthat have been recovered from the Wepener District are theskulls of a basal mastodonsaurid (NM QR3043 cf Watsoni-

suchus Damiani pers obs) from the farm Novo and of thecynodont therapsid Diademodon (Kitching pers comm) fromthe farm Sleepy Hollow The former is almost certainly fromthe lower part (Subzone A) of the Cynognathus AssemblageZone as with all other basal mastodonsaurids (lsquoKestrosaurusrsquoWatsonisuchus Parotosuchus) from the biozone while Diade-modon occurs in all three subzones (Hancox and Rubidge1997) In the neighbouring Cynognathus Assemblage Zone dis-tricts of Zastron and Rouxville fossils from both Subzone Aand Subzone B have been recovered which coupled with themore derived nature of J formops compared to the Subzone Amastodonsaurids suggests assignment to Subzone B

Etymology A combination of lsquoformarsquo Latin for image orlikeness and the suffix -ops meaning lsquofacersquo in reference to theskull roof which is preserved mainly as a natural mold

Diagnosis As for the genus

DESCRIPTION

Preservation

The holotype of Jammerbergia formops consists of a largepartial skull preserved in a reddish-brown fine-grained sand-stone matrix with interspersed mud clasts The specimen hadpreviously been prepared presumably soon after discovery andrequired only minor additional preparation to fully expose thepalatal vacuities and some areas of the occiput With the ex-ception of the posteriormost skull deck most of the bone onthe skull roof was not preserved This surface is instead pre-served mainly as an excellent natural mold which reproducesthe contours of the skull roof and the impressions of underlyingbones including some sutures On the left-hand side of the skullroof a large area of the surface of the mold including the orbitwas not preserved however the right orbit is clearly visible asa rounded matrix-filled area delimited by the smooth surfaceof the mold The rim of the pineal was preserved in a similarway although its posterior half is less distinct and grades intothe smooth surface The surface of the remaining bone is a littleabraded but otherwise well preserved Several large detachedbone fragments of the skull roof were also preserved but theirposition could not be determined Both the palate and the oc-ciput are well preserved with only small areas of bone missingThe skull has suffered some post-mortem crushing especiallyon the left-hand side resulting in some minor distortion of theskull and moderate flattening of the cheek region

Skull Roof

As with the skull of P morganorum that of J formops (Figs5A 6A 7A) displays a slight preorbital step rising toward theorbits which are themselves only slightly elevated above thesurrounding surface of the skull roof Thus the interobitaltrough is only moderately developed From personal observa-tions by the senior author it seems apparent that in more basalmastodonsaurids such as Parotosuchus and Watsonisuchus adistinct preorbital step and deep interorbital trough is devel-oped whereas in more derived taxa including the two describedhere a preorbital step may or may not be present while theorbits tend to become more flush with the skull roof Unlike inP morganorum the exoccipital condyles are positioned wellanterior to the rear border of the skull and are therefore notvisible dorsally A notable feature of the skull roof of J mu-cidiops is the extremely anterior position of the squamosalquadratojugal margin of the skull This results in both a broadlyopen otic notch and the rear border of the skull deck beingpositioned posterior to the squamosalquadratojugal marginThe latter character is autapomorphic for Jammerbergia Fur-thermore this rear border is only moderately concave in J for-


FIGURE 5 Photographs of skull of Jammerbergia formops gen et sp nov (NM QR1436) in A dorsal B ventral and C occipital viewsScale bar equals 10 cm

mops but notably deeper in Paracyclotosaurus and Eryosuchuspronus (Howie 1970)

Dermal bone thickness ranges from 5 mm to 13 mm in plac-es Ornament on the preserved portions of bone is very similarto that of P morganorum in consisting of large irregularlyshaped pits up to 2 mm in depth separated by narrow ridgesup to one millimetre in width A small unornamented area onthe anterior rim of the right otic notch may represent an exca-vatio oticalis (Schoch 1997) Portions of sensory canals presenton the skull and on the detached pieces of bone show that thesewere formed by shallow grooves rather than a series of pits asin P morganorum Sutures on the preserved bone were ex-tremely difficult to trace suggesting a mature or old individual

The shape orientation and position of the tabular horns rel-ative to the otic notch are also highly distinctive in J formopsand quite unlike those of other mastodonsaurids that possesslsquosemi-closedrsquo otic notches In J formops the tabular horns arevery broad and posterolaterally directed as in Paracyclotosau-rus but lack an antero-distal lsquolappetrsquo which in Paracycloto-saurus E pronus (Howie 1970) and Tatrasuchus wildi(Schoch 1997) give the horn a bulbous appearance distallySimilarly shaped tabular horns are present in Wellesaurus pea-bodyi (Welles and Cosgriff 1965) and Wellesaurus africanus(Chernin 1978 Damiani pers obs) but the horns are mark-edly narrower in those taxa Furthermore in each of the above-mentioned taxa the otic notch is moderately to very narrowquite unlike the broadly open otic notch in J formops The

width of the otic notch posteriorly is most unusual for a derivedmastodonsaurid with postero-laterally directed tabular horns

The arrangement of bones on the skull roof appears to havebeen typically mastodonsaurid with frontals entering the orbitalmargin prefrontals that are broader than the frontals and anantero-laterally expanded postorbital The latter nearly excludesthe jugal from entering the orbital margin However it is wellknown from isolated elements that the dorsal and ventral out-lines of any particular skull roofing bone may not necessarilybe in accord (Bystrow and Efremov 1940 Schoch 1999) sothat caution must be exercised when interpreting sutural ar-rangements based on impressions

Palate

The palate (Figs 5B 6B 7B) of J formops also displays anunusual combination of primitive and derived characters Thebody of the parasphenoid forming most of the basicraniumhas a primitively short suture with the pterygoid The centralpart of the body of the parasphenoid forms a sunken area thatlies well below the more posterior portion of the parasphenoidThe latter bears a crista muscularis which lies at the level ofthe posterior border of the pterygoid-parasphenoid suture andforms a true lsquotransverse ridgersquo across the body of the paras-phenoid However this ridge is only weakly developed and isbarely more than one millimetre in height at any point alongits length Just posterior to the pterygoid-parasphenoid suture


FIGURE 6 Interpretive drawings of skull of Jammerbergia formops gen et sp nov (NM QR1436) in A dorsal B ventral and C occipitalviews The dorsal surface (A) is preserved mainly as an internal mold with some sutural impressions Areas not shaded represent broken boneDense stippling represents matrix Scale bar equals 10 cm

the parasphenoid forms a triangular swelling as in many de-rived mastodonsaurids including Mastodonsaurus (Schoch1999) Paracyclotosaurus crookshanki (Mukherjee and Sengup-ta 1998 Damiani pers obs) Paracyclotosaurus morganorumWellesaurus peabodyi (Welles and Cosgriff 1965) and Cher-ninia megarhina (sea Damiani 2001c) This swelling is clearlyderived as it is absent in all basal members of the Mastodon-sauridae Anteriorly the cultriform process is convex ventrallyand there is no hint of a midline lsquokeelrsquo as in P morganorum

The exoccipitals of J formops are quite unlike those of Pmorganorum They lack a long subotic process and consequent-ly do not form a ventral suture with the pterygoid Also theyare not lsquostalkedrsquo and the condylar facets are positioned closeto the posterior border of the parasphenoid The facets facesomewhat inward and postero-ventrally but this may have beenaffected by compaction Remarkably the exoccipital condylesare positioned at the same transverse level as the quadrate con-dyles which is usually characteristic of more derived masto-donsaurids with elongated basicrania andor a ventral exoccip-ital-pterygoid suture (eg Mastodonsaurus ParacyclotosaurusCyclotosaurus Wellesaurus)

The pterygoids are distinctive because of the extreme short-ness of the quadrate rami It is this rather than any aspect ofthe basicranium that results in the quadrate condyles beingaligned at the same transverse level as the occipital condylesAs in P morganorum the oblique ridge of the pterygoids arevisible in palatal view since they diverge dorsally from the as-cending ramus of the pterygoid as discussed below The prox-

imal parts of the palatal rami of the pterygoids are markedlydownturned on their inner margin so that they are considerablywider in this area than is indicated in Figure 6B They arelightly sculptured with ridge-groove type ornamentation andpossess a weak transverse flange Anteriorly the palatal ramusprobably sutured with the palatine but sutures in this area aredifficult to trace

The quadrates are typically mastodonsaurid in being com-posed of a bulbous medial portion which sends a short processalong the inner edge of the quadrate ramus of the pterygoidand a short tapering lateral portion which sutures with quad-ratojugal The overall appearance is vaguely that of an L-shapeas in all mastodonsaurids

Both tabular horns display the usual set of ventral muscularridges characteristic of mastodonsaurids although the ridges areall damaged to some extent The orientations of these ridges donot differ significantly from those of P morganorum Howeverthe crista tabularis externa is extraordinarily tall reaching ap-proximately 13 mm in maximum height far exceeding theheight of the same crest in P morganiorum

Small portions of the maxillary and palatal tooth rows arepreserved but remain partially embedded in matrix Teeth onthe maxilla are broken toward their tips while those of thepalatal row which are from the palatine andor ectopteryoidare complete but lying on their sides The dentition is typicallymastodonsaurid in that teeth are very closely spaced markedlycompressed antero-posteriorly and slightly recurved medially


FIGURE 7 Reconstructed outline of skull of Jammerbergia formops gen et sp nov (NM QR1436) in A dorsal B ventral and C occipitalviews Scale bar equals 10 cm

Occiput

The occiput (Figs 5C 6C 7C) of J formops is fully pre-served and shows a deep cheek region similar to Wellesauruspeabodyi (Welles and Cosgriff 1965) Eryosuchus pronus(Howie 1970) Cyclotosaurus (Ingavat and Janvier 1981) andMastodonsaurus (Schoch 1999) However the depth of thecheek region is clearly subject to compaction and relies on es-sentially uncrushed material that can rarely be expected in dor-so-ventrally flattened animals such as mastodonsaurids Similarconstraints further hampered by subjectivity apply to estimatesof the overall lsquodepthrsquo of the occiput For instance what consti-tutes a lsquoshallowrsquo or a lsquodeeprsquo occiput As with the skull roofsutural impressions on the more lateral parts of the occiput wereextremely difficult to trace and individual bones of the occiputare all massively ossified

The most prominent aspect of the occiput is the massivelydeveloped ridges for muscular attachment on the postparietalstabulars and paroccipital processes The posterior margin of the

skull roof is exceptionally thick and rounded and prominentlyoverhangs the entire occiput In the midline of this margin thespina supraoccipitalis of the postparietals (Bystrow and Efre-mov 1940) forms a deep process which partially obstructs thesupraoccipital foramen Both this foramen and the foramenmagnum below it are slightly irregular in shape as a result ofcompaction

The posttemporal fenestrae are exceptionally narrow and inoccipital view are completely hidden by the deep overhangingcrista muscularis formed by the postparietal and tabular Thefenestrae are also narrowed by the massive paroccipital pro-cesses each of which bears an exceptionally large ventrallydirected crista muscularis on its tabular portion

The quadrate ramus of the pterygoid gives rise to two prom-inent processes on the occipital face of the skull the ascendingramus and the oblique ridge The ascending ramus is a tallmedially curved sheet of bone that sutures firmly with and ispartly overhung by the occipital flange of the squamosal pos-


tero-dorsally It also forms the anterior wall of the middle earcavity Anteriorly the ascending ramus curves medially beneaththe otic notch where it appears to terminate in a free marginclose to the pterygoid-parasphenoid suture Although largelyhidden by the basicranium the dorsal part of this margin ap-pears to be positioned medial to the ventral part and as in allstereospondyls except brachyopids (Damiani and Warren1996) a thickening of this margin the crista praeotica occursThe ascending ramus is largely hidden in occipital view by theoblique ridge The latter is similar to that of Paracyclotosaurusmorganorum in diverging from the ascending ramus dorsallybut differs from it in being much less tall and rising only ashort distance above its point of origin as in Wellesaurus af-ricanus (Damiani pers obs)

The squamosal is characterized by an occipital flange whichsutures with the ascending ramus of the pterygoid and the mas-sive crista falciformis which is oriented diagonally and projectssome 25 mm from the occipital flange of the squamosal Theoccipital flange is unusual in lacking a deep occipital exposureas is usually the case in mastodonsaurids and more closelyresembles the foreshortened occipital flange of the squamosalin Cyclotosaurus (Maryanska and Shishkin 1996)

The quadratojugal is remarkable because of the presence ofan exceptionally large medial process which sutures with thequadrate ramus of the pterygoid This results largely from theshortness of the occipital flange of the squamosal Such a con-tact has been described previously only in Mastodonsaurus gi-ganteus (Schoch 1999) The quadratojugal completely enclosesthe paraquadrate foramen as is usually the case in mastodon-saurids However there appears to be some variability in thearrangement of bones contributing to the margin of this fora-men For instance in both P crookshanki (Mukherjee and Sen-gupta 1998) and W peabodyi (Welles and Cosgriff 1965) theforamen is bordered by the quadrate quadratojugal and squa-mosal On the left side of the skull a tiny foramen appears tobe present next to the paraquadrate foramen This foramen maybe an artefact of preparation as a foramen in this position hasnever been reported in mastodonsaurids Unfortunately the oc-ciput is damaged in the corresponding area of the right side ofthe skull

Despite the large size and massive ossification of the animalthe quadrate lacks a well-defined lsquobossrsquo on its medial edge

DISCUSSION

The intrarelationships of mastodonsaurids (lsquocapitosauridsrsquo)and mastodonsauroids (lsquocapitosauroidsrsquo) have long been debat-ed by temnospondyl workers there remains little consensuseven today despite a number of proposed phylogenetic hypoth-eses (Paton 1974 Ingavat and Janvier 1981 Kamphausen andMorales 1981 Kamphausen 1989 Maryanska and Shishkin1996 Schoch 2000b c Schoch and Milner 2000 Damiani2001b) However in addition to the taxa described in this paperthe recent descriptions of Quasicyclotosaurus campi and Eocy-clotosaurus wellesi by Schoch (2000d) and the redescriptionsof Mastodonsaurus giganteus by Schoch (1999) and Cherniniamegarhina by Damiani (2001c) have provided a wealth of newanatomical data and the stimulus for further phylogenetic re-search Such an analysis is beyond the scope of this paper buta new much larger phylogenetic analysis including a consid-eration of all characters used by previous workers is currentlyin preparation by the senior author Here the phylogenetic po-sition of Jammerbergia formops will be only briefly discussed

The most recent hypotheses of mastodonsaurid relationshipsare those presented by Damiani (2001b) and Schoch the latterformulated in a series of papers (Schoch 2000b c Schoch andMilner 2000) Despite little overlap in the characters used thecladograms presented were much in agreement In particular

both hypotheses showed a series of basal taxa (ParotosuchusWatsonisuchus [the latter represented by Watsonisuchus aliciaein Schochrsquos phylogeny]) forming successive outgroups to aclade of lsquoadvancedrsquo mastodonsaurids characterized by amongstother characters laterally directed tabular horns Paracycloto-saurus was included within this lsquoadvancedrsquo mastodonsauridclade in Damianirsquos analysis (the taxon was not included inSchochrsquos analysis) but in a fairly basal position The presenceof laterally directed tabular horns in J formops suggests that itbelongs within this lsquoadvancedrsquo mastodonsaurid clade HoweverJ formops is unique among mastodonsaurids because of theunusual combination of primitive and derived characters Inparticular the presence of laterally directed tabular horns theswelling of the body of the parasphenoid laterally and the ex-ceptionally short quadrate ramus of the pteryoid are unusual incombination with the lack of a ventral exoccipital-pterygoidcontact and the short pterygoid-parasphenoid suture On thisbasis we suspect that J formops occupies a very basal positionwithin the lsquoadvancedrsquo mastodonsaurid clade perhaps as the sis-ter taxon of Paracyclotosaurus a relationship supported by thesynapomorphy of large antero-posteriorly expanded tabulars

The description of P morganorum and J formops brings tofive the number of valid mastodonsaurid genera from the Cy-nognathus Assemblage Zone alongside Watsonisuchus (Dam-iani 2001b) Parotosuchus (Damiani 1999 2001a) and Wel-lesaurus (Damiani 2001b) However this is not remarkablegiven the length of time spanned by the Cynognathus Assem-blage Zone namely Upper Olenekian to late Anisian and thefact that the biozone is biostratigraphically subdivided intothree distinct subzones of differing ages and faunas (Hancox etal 1995 Shishkin et al 1995 Hancox and Rubidge 1997Hancox 1998 2000) With regards to the temnospondyls Sub-zone A of Upper Olenekian age contains Watsonisuchus andParotosuchus the trematosaurid Trematosuchus (Shishkin andWelman 1994) the rhytidosteid Rhytidosteus (Shishkin 1994)and a new brachyopid (Damiani and Jeannot submitted) Sub-zone B of early Anisian age is characterized by the presenceof Wellesaurus Jammerbergia the trematosaurid Microposau-rus (Haughton 1925 unpublished information) and the brach-yopid Vanastega (Damiani and Kitching 2003) Finally Sub-zone C of late Anisian age contains Paracyclotosaurus alongwith as-yet-undescribed mastodonsaurid mandibles (Damianiin preparation) similar to those of Eryosuchus pronus from theManda Formation of Tanzania (Howie 1970) and the UpperNrsquotawere Formation of Zambia (Chernin 1974) Both the Man-da and Upper Nrsquotawere formations have long been consideredAnisian or late Anisian in age (Anderson and Anderson 1970Ochev and Shishkin 1989 Battail 1993 Hancox 2000) theformer being directly correlatable with Subzone C based on thepresence in both faunas of the dicynodont Angonisaurus (Han-cox and Rubidge 1996) If the assignment of the mandibles toE pronus is correct they provide a direct correlation betweenthe three faunas and further evidence of a late Anisian age forSubzone C of the Cynognathus Assemblage Zone

ACKNOWLEDGMENTS

We are grateful to Dr Johann Welman (National MuseumBloemfontein) for the loan of NM QR1436 Mr Charlton Dube(BPI Johannesburg) for its preparation Mr Richard Lewis (for-merly BPI Johannesburg) for technical assistance and the Cen-tral Photographic Service of the University of the Witwaters-rand for printing the photographs Dr Dhurjati Sengupta (IndianStatistical Institute Calcutta) verified our suspicions regardingthe tranposed figure captions in Mukherjee and Senguptarsquos(1998) paper and Professor James Kitching (BPI Johannes-burg) provided information on Laidleria and the Diademodonspecimen he found in the Wepener District The senior author


is grateful to Dr Jenny Clack (UMZC) and Ms Sandra Chap-man (Natural History Museum London) for access to speci-mens in their care The junior author would like to thank theMorgan family of the Bamboeshoek Valley Eastern Cape Prov-ince for their hospitality while conducting field work in thearea Comments on the manuscript by Drs Rainer Schoch andAndrew Milner improved the quality of this paper This workwas supported by the University of the Witwatersrand and theNational Research Foundation of South Africa

LITERATURE CITED

Anderson H M and J M Anderson 1970 A preliminary review ofthe biostratigraphy of the uppermost Permian Triassic and lower-most Jurassic of Gondwanaland Palaeontologia africana 131ndash22

Anderson J M and A R I Cruickshank 1978 The biostratigraphyof the Permian and the Triassic Part 5 a review of the classifi-cation and distribution of Permo-Triassic tetrapods Palaeontologiaafricana 2115ndash44

Battail B 1988 Biostratigraphie des formations Permo-Triasiques con-tinentales a Vertebres tetrapodes et biogeographie du GondwanaAnnales de la Societe Geologique du Nord 10737ndash44

mdashmdashmdash 1993 On the biostratigraphy of Triassic therapsid-bearing for-mations New Mexico Museum of Natural History amp Science Bul-letin 331ndash35

Broili F and J Schroder 1937 Beobachtungen an Wirbeltieren derKarrooformation XXVII Uber einen Capitosauriden aus der Cy-nognathus-Zone Sitzungsberichte der bayerischen Akademie derWissenschaften 193797ndash117

Broom R 1904 On a new South African labyrinthodont (Cyclotosau-rus albertyni) Records of the Albany Museum 1178ndash180

mdashmdashmdash 1909 Notice of some new South African fossil amphibians andreptiles Annals of the South African Museum 7270ndash278

Bystrow A P and J A Efremov 1940 Benthosuchus sushkini Efre-movmdasha labyrinthodont from the Eotriassic of the Sharzenga RiverTrudy Paleontologicheskogo Instituta 101ndash152 [Russian]

Chernin S 1974 Capitosaurid amphibians from the Upper LuangwaValley Zambia Palaeontologia africana 1729ndash55

mdashmdashmdash 1978 Three capitosaurs from the Triassic of South Africa Par-otosuchus africanus (Broom 1909) Kestrosaurus dreyeri Haughton1925 and Parotosuchus dirus sp nov Palaeontologia africana 2179ndash100

Cooper M R 1982 A mid-Permian to earliest Jurassic tetrapod bio-stratigraphy and its significance Arnoldia Zimbabwe 977ndash104

Cosgriff J W 1965 A new genus of Temnospondyli from the Triassicof Western Australia Journal of the Royal Society of Western Aus-tralia 4865ndash90

mdashmdashmdash 1984 The temnospondyl labyrinthodonts of the earliest TriassicJournal of Vertebrate Paleontology 430ndash46

Cruickshank A R I 1986 Biostratigraphy and classification of a newTriassic dicynodont from East Africa Modern Geology 10121ndash131

Damiani R J 1999 Parotosuchus (Amphibia Temnospondyli) inGondwana biostratigraphic and palaeobiogeographic implicationsSouth African Journal of Science 95458ndash460

mdashmdashmdash 2001a Parotosuchus (Amphibia Temnospondyli) from the Cy-nognathus Assemblage Zone (Early Triassic) of South Africa cra-nial morphology and relationships Alcheringa 25351ndash379

mdashmdashmdash 2001b A systematic revision and phylogenetic analysis of Tri-assic mastodonsauroids (Temnospondyli Stereospondyli) Zoolog-ical Journal of the Linnean Society 133379ndash482

mdashmdashmdash 2001c Cranial anatomy of the giant Middle Triassic temnos-pondyl Cherninia megarhina and a review of feeding in masto-donsaurids Palaeontologia africana 3741ndash52

mdashmdashmdash and J W Kitching 2003 A new brachyopid temnospondylfrom the Cynognathus Assemblage Zone Upper Beaufort GroupSouth Africa Journal of Vertebrate Paleontology 2367ndash78

mdashmdashmdash and A A Warren 1996 A new look at members of the Su-perfamily Brachyopoidea (Amphibia Temnospondyli) from theEarly Triassic of Queensland and a preliminary analysis of brach-yopoid relationships Alcheringa 20277ndash300

DuToit A L 1954 The Geology of South Africa Oliver and BoydEdinburgh and London 611 pp

Groenewald G H 1996 Stratigraphy and sedimentology of the Tar-

kastad Subgroup Karoo Supergroup South Africa PhD disser-tation University of Port Elizabeth Port Elizabeth 145 pp

Hancox P J 1998 A stratigraphic sedimentological and palaeoenvi-ronmental synthesis of the Beaufort-Molteno contact in the KarooBasin PhD dissertation University of the Witwatersrand Johan-nesburg 404 pp

mdashmdashmdash 2000 The continental Triassic of South Africa Zentralblatt furGeologie und Palaontologie Teil I 19981285ndash1324

mdashmdashmdash R J Damiani and B S Rubidge 2000 First occurrence ofParacyclotosaurus (Temnospondyli Capitosauridae) in the KarooBasin of South Africa and its biostratigraphic significance SouthAfrican Journal of Science 96135ndash137

mdashmdashmdash and B S Rubidge 1996 The first specimen of the Mid-Triassicdicynodont Angonisaurus from the Karoo of South Africa impli-cations for the dating and biostratigraphy of the Cynognathus As-semblage Zone Upper Beaufort Group South African Journal ofScience 92391ndash392

mdashmdashmdash and mdashmdashmdash 1997 The role of fossils in interpreting the de-velopment of the Karoo Basin Palaeontologia africana 3341ndash54

mdashmdashmdash M A Shishkin B S Rubidge and J W Kitching 1995 Athreefold subdivision of the Cynognathus Assemblage Zone (Beau-fort Group South Africa) and its palaeogeographical implicationsSouth African Journal of Science 91143ndash144

Haughton S H 1925 Investigations in South African fossil reptilesand Amphibia (Part 13) Annals of the South African Museum 22227ndash261

Howie A A 1970 A new capitosaurid labyrinthodont from East Af-rica Palaeontology 13210ndash253

Huene F von 1940 Die Saurier der Karroo- Gondwana- und ver-wandten Ablagerungen in faunistischer biologischer und phyloge-netischer Hinsicht Neues Jahrbuch fur Mineralogie Geologie undPalaontologie Abt B 83246ndash347

Ingavat R and P Janvier 1981 Cyclotosaurus cf posthumus Fraas(Capitosauridae Stereospondyli) from the Huai Hin Lat Formation(Upper Triassic) northeastern Thailand with a note on capitosauridbiogeography Geobios 14711ndash725

Johnson M R 1994 Lexicon of South African Stratigraphy Councilfor Geoscience Pretoria 56 pp

Kamphausen D 1989 Der Schadel von Eocyclotosaurus woschmidtiOrtlam (Amphibia Stegocephalia) aus dem Oberen Buntsandstein(Trias) der Schwarzwaldes (SW-Deutschland) Stuttgarter Beitragezur Naturkunde Serie B 1491ndash65

mdashmdashmdash 1994 Eine Schadelasymmetrie bei Cyclotosaurus Fraas (Am-phibia Stegocephalia) aus dem Stubensandstein (Trias) von Wurt-temberg (SW-Deutschland) Stuttgarter Beitrage zur NaturkundeSerie B 2101ndash12

mdashmdashmdash and M Morales 1981 Eocyclotosaurus lehmani a new com-bination for Stenotosaurus lehmani Heyler 1969 (Amphibia)Neues Jahrbuch fur Geologie und Palaontologie Monatshefte 1981651ndash656

Kitching J W 1958 A new small stereospondylous labyrinthodontfrom the Triassic beds of South Africa Palaeontologia africana 567ndash82

mdashmdashmdash 1977 The distribution of the Karroo vertebrate fauna BernardPrice Institute for Palaeontological Research Memoir No 11ndash131

Latimer E M 1998 Rhinesuchoid temnospondyls from the Karoo ofSouth Africa and their use in biostratigraphic correlations Journalof Vertebrate Paleontology 1858A

Laurin M 1998 The importance of global parsimony and historicalbias in understanding tetrapod evolution Part I Systematics mid-dle ear evolution and jaw suspension Annales des Sciences Na-turelles 19981ndash42

Lucas S G 1998 Global Triassic tetrapod biostratigraphy and bio-chronology Palaeogeography Palaeoclimatology Palaeoecology143347ndash384

Lydekker R 1885 The Reptilia and Amphibia of the Maleri and DenwaGroups Palaeontologia Indica (Ser IV Indian pre-Tertiary Verte-brata) 1(5)30ndash38

Maryanska T and M A Shishkin 1996 New cyclotosaurid (Am-phibia Temnospondyli) from the Middle Triassic of Poland andsome problems of interrelationships of capitosauroids Prace Mu-zeum Ziemi 4353ndash83

Mukherjee R N and D P Sengupta 1998 New capitosaurid amphib-ians from the Triassic Denwa Formation of the Satpura GondwanaBasin Central India Alcheringa 22317ndash327


Ochev V G and M A Shishkin 1989 On the principles of globalcorrelation of the continental Triassic on the tetrapods Acta Pa-laeontologica Polonica 34149ndash173

Owen R 1884 On a labyrinthodont amphibian (Rhytidosteus capensis)from the Trias of the Orange Free State Cape of Good Hope Quar-terly Journal of the Geological Society of London 40333ndash339

Paton R 1974 Capitosauroid labyrinthodonts from the Trias of Eng-land Palaeontology 17253ndash290

Rubidge B S 1995 Biostratigraphy of the Beaufort Group (KarooSupergroup) South African Committee for Stratigraphy Biostrati-graphic Series No 1 Council for Geoscience Pretoria 46 pp

Schoch R R 1997 A new capitosaur amphibian from the Upper Let-tenkeuper (Triassic Ladinian) of Kupferzell (Southern Germany)Neues Jahrbuch fur Geologie und Palaontologie Abhandlungen203239ndash272

mdashmdashmdash 1999 Comparative osteology of Mastodonsaurus giganteus(Jaeger 1828) from the Middle Triassic (Lettenkeuper Longobar-dian) of Germany (Baden-Wurttemberg Bayern Thuringen) Stutt-garter Beitrage zur Naturkunde Serie B 2781ndash175

mdashmdashmdash 2000a The stapes of Mastodonsaurus giganteus (Jaeger1828)mdashstructure articulation ontogeny and functional implica-tions Neues Jahrbuch fur Geologie und Palaontologie Abhandlun-gen 215177ndash200

mdashmdashmdash 2000b Biogeography of stereospondyl amphibians Neues Jahr-buch fur Geologie und Palaontologie Abhandlungen 215201ndash231

mdashmdashmdash 2000c The origin and intrarelationships of Triassic capitosauridamphibians Palaeontology 43705ndash727

mdashmdashmdash 2000d The status and osteology of two new cyclotosaurid am-phibians from the Upper Moenkopi Formation of Arizona (Am-phibia Temnospondyli Middle Triassic) Neues Jahrbuch fur Geo-logie und Palaontologie Abhandlungen 216387ndash411

mdashmdashmdash and A R Milner 2000 Stereospondyli Encyclopedia of Pa-leoherpetology Part 3B Verlag Dr Friedrich Pfeil Munchen 203pp

Sennikov A G 1981 A new wetlugasaur from the Samara River BasinPaleontological Journal 1981111ndash116

Shishkin M A 1994 A Gondwanan rhytidosteid (Amphibia Temnos-pondyli) from the Lower Triassic of southern Cisuralia Paleonto-logical Journal 28127ndash143

mdashmdashmdash and V G Ochev 1994 Problems of global correlation of thecontinental Triassic on the basis of tetrapods Memoires de Geo-logie (Lausanne) 22121ndash125

mdashmdashmdash B S Rubidge and P J Hancox 1995 Vertebrate biozonationof the Upper Beaufort Series of South Africamdasha new look on cor-relation of the Triassic biotic events in Euramerica and southernGondwana pp 39ndash41 in A Sun and Y Wang (eds) Sixth Sym-posium on Mesozoic Terrestrial Ecosystems and Biota Short Pa-pers 1995 China Ocean Press Beijing

mdashmdashmdash B S Rubidge and J W Kitching 1996 A new lydekkerinid

(Amphibia Temnospondyli) from the Lower Triassic of South Af-ricamdashimplications for evolution of the early capitosauroid cranialpattern Philosophical Transactions of the Royal Society of LondonB 3511635ndash1659

mdashmdashmdash and J Welman 1994 A new find of Trematosuchus (Amphib-ia Temnospondyli) from the Cynognathus Zone of South AfricaPalaeontologia africana 3139ndash49

Shubin N H and H-D Sues 1991 Biogeography of early Mesozoiccontinental tetrapods patterns and implications Paleobiology 17214ndash230

Warren A A 1998 Laidleria uncovered a redescription of Laidleriagracilis Kitching (1957) a temnospondyl from the CynognathusZone of South Africa Zoological Journal of the Linnean Society122167ndash185

mdashmdashmdash 1999 Karoo tupilakosaurid a relict from Gondwana Transac-tions of the Royal Society of Edinburgh Earth Sciences 89145ndash160

mdashmdashmdash and M N Hutchinson 1988 A new capitosaurid amphibianfrom the Early Triassic of Queensland and the ontogeny of thecapitosaur skull Palaeontology 31857ndash876

mdashmdashmdash and N Schroeder 1995 Changes in the capitosaur skull withgrowth an extension of the growth series of Parotosuchus aliciae(Amphibia Temnospondyli) with comments on the otic area ofcapitosaurs Alcheringa 1941ndash46

Watson D M S 1958 A new labyrinthodont (Paracyclotosaurus) fromthe Upper Trias of New South Wales Bulletin of the British Mu-seum (Natural History) Geology 3233ndash263

Watson D M S 1962 The evolution of the labyrinthodonts Philo-sophical Transactions of the Royal Society of London B 245219ndash265

Welles S P and J W Cosgriff 1965 A revision of the labyrinthodontfamily Capitosauridae and a description of Parotosaurus peabodyin sp from the Moenkopi Formation of Northern Arizona Univer-sity of California Publications in Geological Sciences 541ndash148

Yates A M and A A Warren 2000 The phylogeny of the lsquohigherrsquotemnospondyls (Vertebrata Choanata) and its implications for themonophyly and origins of the Stereospondyli Zoological Journalof the Linnean Society 12877ndash121

Zittel K A von 1887ndash1890 Handbuch der Palaontologie Abteilung1 Palaozoologie Band III Vertebrata (Pisces Amphibia ReptiliaAves) Oldenbourg Munich and Leipzig 900 pp

Received 3 November 2000 accepted 30 April 2002

Note added to proof After this paper had been accepted for publi-cation the holotype specimen of Jammerbergia formops Damiani andHancox which had been on loan to the senior author was stolen inBloemfontein prior to it being returned to the National Museum Thesenior author may be contacted for further information surrounding theloss

54

Journal of Vertebrate Paleontology 23(1)54ndash66 March 2003q 2003 by the Society of Vertebrate Paleontology

NEW MASTODONSAURID TEMNOSPONDYLS FROM THE CYNOGNATHUS ASSEMBLAGEZONE (UPPER BEAUFORT GROUP KAROO BASIN) OF SOUTH AFRICA

ROSS J DAMIANI1 and P JOHN HANCOX2

1Bernard Price Institute for Palaeontological Research University of the Witwatersrand Private Bag 3 Wits 2050South Africa damianirgeoscienceswitsacza

2Department of Geology University of the Witwatersrand Private Bag 3 Wits 2050 South Africa

ABSTRACTmdashTwo new mastodonsaurid temnospondyls are described from the Early to Middle Triassic CynognathusAssemblage Zone of the Upper Beaufort Group (Karoo Basin) of South Africa Paracyclotosaurus morganorum spnov is based on a partial skull from the uppermost part of the Cynognathus Assemblage Zone (Subzone C lateAnisian) in the southern Karoo Basin and is the first occurrence of the genus Paracyclotosaurus outside of India andAustralia Jammerbergia formops gen et sp nov is based on a partial skull presumably from Subzone B (earlyAnisian) of the Cynognathus Assemblage Zone and is distinctive in its unique suite of primitive and derived charactersAlthough the intrarelationships of mastodonsaurids remain largely unresolved the two most recent analyses are similarin the identification of an lsquoadvancedrsquo mastodonsaurid clade whose members are characterized by laterally directedtabular horns Jammerbergia probably belongs within this clade albeit within a basal position Jammerbergia andParacyclotosaurus share the synapomorphy of large antero-posteriorly expanded tabulars and may represent sistertaxa The Cynognathus Assemblage Zone is characterized by three subzones of differing ages and faunas with nooverlap in the temnospondyls between the subzones

INTRODUCTION

Temnospondyls form an important part of the fauna of thePermo-Triassic Beaufort Group of the Karoo Basin of SouthAfrica but have tended to be neglected in favor of studies ontherapsids which form the basis for the eight-fold biostrati-graphic subdivision of the Beaufort Group (Rubidge 1995)Recently there has been a resurgence in studies of BeaufortGroup temnospondyls including taxonomic descriptions of newspecies (Shishkin et al 1996 Warren 1999 Damiani andKitching 2003) descriptions of new material of existing spe-cies (Shishkin and Welman 1994 Damiani 2001a) and taxo-nomic reassessments of older material (Warren 1998 Latimer1998) Compared with other Beaufort Group biozones the Earlyto Middle Triassic Cynognathus Assemblage Zone (Fig 1) hasan abundance of temnospondyl material The main temnospon-dyl representatives within this biozone are the Mastodonsauri-dae the senior synonym of the better known Capitosauridae(Damiani 2001b) and are represented by the following diag-nostic taxa Watsonisuchus magnus (Watson 1962 Damiani2001b) Parotosuchus haughtoni (Broili and Schroder 1937Damiani 2001a) Wellesaurus africanus (Broom 1909 Dami-ani 2001b) Rarer temnospondyl components of the Cynogna-thus Assemblage Zone include the Trematosauridae Brachyop-idae Rhytidosteidae and Laidleriidae The Laidleriidae arehowever known from only a single specimen Laidleria gracilis(Kitching 1958 Warren 1998) which is questionably from theunderlying Lystrosaurus Assemblage Zone (Kitching perscomm)

During recent fieldwork by the junior author in the Bam-boeshoek Valley of the Eastern Cape Province a new tetrapodfaunal assemblage was discovered in the southern Karoo BasinThis new fauna contains the cynodont therapsid Cynognathusand may therefore be broadly assigned to the Cynognathus As-semblage Zone The fauna also contains at least two dicynodontgenera previously unknown from the biozone as well as a newmastodonsaurid recently reported by Hancox et al (2000) torepresent a new species of the genus Paracyclotosaurus a tax-on previously known only from the Middle Triassic of Australia

(P davidi Watson 1958) but recently shown (Damiani 2001b)to also include a newly described Indian species (lsquoParotosu-chusrsquo crookshanki Mukherjee and Sengupta 1998) This newspecies is fully described below In addition during a recentinspection by the senior author of the temnospondyl collectionof the National Museum Bloemfontein a large previously un-described mastodonsaurid was found This specimen apparent-ly from the Cynognathus Assemblage Zone represents a newgenus and species and is described below

The aim of this paper is to fully describe the new mastodon-saurid material and to compare it with other mastodonsauridsincluding in particular those from the Cynognathus AssemblageZone of South Africa The increasingly important role that tem-nospondylsmdashand mastodonsauroids in particularmdashare playingin biostratigraphy and correlation of Triassic terrestrial tetrapodfaunas both locally (Hancox et al 1995 Shishkin et al 1995Hancox and Rubidge 1997) and globally (Ochev and Shishkin1989 Shubin and Sues 1991 Lucas 1998) underscores theimportance of documenting and accurately describing new tem-nospondyl material from the Triassic

Age of the Cynognathus Assemblage Zone

Despite the abundance of both therapsid and temnospondylmaterial in the Cynognathus Assemblage Zone its age has beenmuch debated It has variously been considered Early Triassic(DuToit 1954 Cosgriff 1965 Anderson and Anderson 1970Chernin 1978) late Early Triassic (Anderson and Cruickshank1978 Cosgriff 1984 Battail 1988 1993) or Middle Triassic(Huene 1940 Kitching 1977 Cruickshank 1986 Ochev andShishkin 1989 Shubin and Sues 1991 Shishkin and Ochev1994) Recently Lucas (1998) made the Cynognathus Assem-blage Zone the type assemblage for his Nonesian LVF (LandVertebrate Faunachron) of Olenekian age In marked contrastCooper (1982) assigned the biozone a Late Permian to EarlyTriassic age while the lexicon of South African stratigraphy(Johnson 1994) assigns the Burgersdorp Formation the strati-graphical unit encompassing the Cynognathus AssemblageZone a Permian age Finally Groenewald (1996) assigned the



























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ACKNOWLEDGMENTS




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DESCRIPTION

Preservation






Skull Roof









Palate

















Stapes













DESCRIPTION

Preservation


Skull Roof









Palate













Occiput











DISCUSSION





ACKNOWLEDGMENTS




LITERATURE CITED
















































































Skull Roof









Palate

















Stapes













DESCRIPTION

Preservation


Skull Roof









Palate













Occiput











DISCUSSION





ACKNOWLEDGMENTS




LITERATURE CITED


















































































Palate

















Stapes













DESCRIPTION

Preservation


Skull Roof









Palate













Occiput











DISCUSSION





ACKNOWLEDGMENTS




LITERATURE CITED




























































































Stapes













DESCRIPTION

Preservation


Skull Roof









Palate













Occiput











DISCUSSION





ACKNOWLEDGMENTS




LITERATURE CITED




















































































Palate













Occiput











DISCUSSION





ACKNOWLEDGMENTS




LITERATURE CITED
























































































Occiput











DISCUSSION





ACKNOWLEDGMENTS




LITERATURE CITED


















































































DISCUSSION





ACKNOWLEDGMENTS




LITERATURE CITED















































































LITERATURE CITED













































































new mastodonsaurid temnospondyls from the cynognathus assemblage zone...

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