Bollettino della Società Paleontologica Italiana Modena, Novembre 1999
Multielement Neogondolella (Conodonta, upper Permian- middle Triassic)
Michael J. 0RCHARD Hans RIEBER Geological Survey of Canada Palaomologisches Institut und Museum Vancouver Universitat Zi.irich
KEYWORDS- Conodonts, Neogondolella, Multielement apparatus, Permian, Triassic.
ABSTRACT- Neogondolella is reconstructed as a multielement conodont genus bearing eight kinds ofelements, seven ofwhich are paired, making a total offifteen elements in al!. The Pa element is segminiplanate, the Pb angulate, Sa is alate, Sbl is breviform digyrate, Sb2 is dolobrate, Scl resembles tertiopedate, Sc2 is bipennate, and M is breviform digyrate. The Sa and Se elements commonly occur as separate anterior and posterior parts. This reconstruction is based on abundant collections ofdisjunct elements and is supported by natura! assemblages ojNeogondolella from Switzerland. The apparatus remained essentially the same from the Upper Permian through the Middle Triassic, with rel4tively minor changes in the morphology o{some elements regarded as ofspecific rank. The apparatus ojNeogondolella diffèrs ftom that ofother Triassic taxa which are nevertheless united in bearing enantiognathiform Sb l elements, on which basis they are classe d as members ofthe supeifamily Gondolellacea. from the Sb elements, the morphology and apparatus pl4n ofgondolel/4ceans generally correspond to that ofthe Ozarkodinida. Within the Jamily Gondolellidae, Gondolella and Neogondo1èlla can be distinguished on multielement grounds.
RIASSUNTO- [L apparato di Neogondolella (Con odo ma, Permiano su p.-Triassico medio)]- L'apparato dei conodonti del genere Neogondolella risulta formato da otto diversi tipi di elementi: sette dei quali sono doppi, quindi l'apparato consta di quindici moifoelementi. L'elemento Pa è segminipl4nato, il Pb angulato, l'Sa af4to, Sbl digyrato breviforme, Sb2 do/4brato, Scl sembra terziopedato, Sc2 è bipennato ed M è digyrato breviforme. Gli elementi Sa e Se vengono di norma ritovati con le parti anteriore eposteriore separate. La ricostruzione è basata su abbondanti collezioni di moifoelementi e su associazioni naturali di Neogondolella in Svizzera. L'apparato nel complesso rimane lo stesso dal Permiano superiore al Triassico medio, con alcune modifiche solo nella mor{ologia di alcuni elementi, che vengono considerate di interesse diagnostico a livello specifico. L'apparato di Neogondolella diffèrisce da quelli degli altri taxa Triassici, che hanno l'elemento Sb l enantiognathiforme, e che per questo vengono attribuiti al/4 famiglia Gondoleffacea. Esclusi gli elementi Sb, la moifologia e la struttura dell'apparato dei Gondolelfacea e simile a quel/4 degli Ozarkidinida. Nel/4 jàmiglia Gondolellidae, sul/4 base dell'apparato, èpossibile distinguere Gondolel1a e Neogondolella.
INTRODUCTION (Sweet, 1988, fig. 5.28). The common and stratigra- phically useful Triassic elements are almost entirely Triassic conodont apparatuses are relatively poorly assigned to the former family, which includes both known in spite of having been amongst the first to be seximembrate and unimembrate appararuses according interpreted in multielement terms (Huckriede, 1958). to Sweet (1988, p. 87). Other researchers ho l d the view This is due primarily to the extreme rarity ofTriassic that the appararuses of ali gondolellids are multi- natura! assemblage templates, but both morphological element, at least during infancy, and essentially the same convergence and process fragility have rendered in composition (e.g. Kozur, 1989a; Hirsch, 1994a). In statistica! reconstructs difficult. In this paper, the this paper, Neogondolella and other gondolellids are apparatus of the common and long-ranging conodont excluded from the Prioniodinida primarily because Neogondolella is reconstructed. This is accomplished their apparatus does not fearure a digyrate Pb element using collections of well preserved and low diversity but rather an angulate element like the ozarkodinides. discrete elements from Permian and Triassic strata of lt is also recognized that there are severa! different North America and Eurasia. These collections facilitate apparatus types represented amongst the taxa presently an understanding of the gross morphology of the combined within the Gondolellidae. frequently broken ramiform elements, which in rum A diverse generic nomenclarure of gondolellid leads to insights imo how they were configured in the conodonts has developed based on the morphological collapsed apparatuses that are now preserved as features and supposed phyletic relationships of the Pa Neogondolella natura! assemblages in the Middle Triassic platform elements. The proposed Neogondolella of Switzerland (Rieber, 1980; Orchard & Rieber, in multielement apparatus, although relatively conserva- prep.). tive and long-ranging, differs from that of many other A common view ofTriassic conodonts is that most Triassic conodonts and facilitates new ideas on phyletic taxa are closely related variations on a prioniodinide relationships. Multielement reconstructions supporta root stock that diverged in the Late Carboniferous as revised classification, an d strengthen biochronological two families, the Gondolellidae and the Ellisonidae schemes. 476 M.] ORCHARD, H. RIEBER
FIRST REPORTS
The earliest descriptions of Triassic Neogond- olella-bearing faunas, at that time referred to Gondole/la, were from the Middle Triassic Muschelkalk of Germany (Tatge, 1956). Later, Bender & Stoppe! (1965) introduced the name Neogondolella with N. mombergensis Tatge as the type species (Text-fìg. 1). Concurrent with her description of N mombergensis, Tatge (1956) also described the pectiniform element Ozarkodina ( =Nicoraella) kockeli an d many new ramiform elements, severa! of them incompletely preserved, as single element- or form-species. These ramiform elements were parts ofboth the Neogondolella and Nicoraella apparatuses. The Tatge form-species (Text-fìg.2) that are regarded as parts of the Neo- gondole/la apparatus are listed below: most of these carne from the same stratum and locality. The proposed notation is shown in brackets, with proximal and distai referring to relative position of element parts with respect to the cusp.
Text-fìg.1-Neogondolellamombergensis(Tatge, 1956). 1-3) Upper, lower, and latera! views, x80, holotype (Ta 1956/5), a dPa element from the Upper Muschelkalk (1.6 m below top of the Trochitenkalk) in the Schmidtdiel Quarry of Momberg, Marburg District, Germany.
THE GENUS NEOGONDOLELLA
The genus Gondole/la was introduced for 'gondola- shaped' (segminiplanate) platform elements from the Upper Carboniferous (Stauffer & Plummer, 1932). These elements were characteristically coarsely-ribbed whereas Neogondolella was introduced for the much younger (at the time), morphologically similar bur generally unornamented segminiplanate Permian- Triassic species (Ben der & Stoppe!, 1965). This distinction based on ornament was not universally applicable however, and much subsequent discussion focussed on what criteria could be used to distinguish the two genera (e.g. von Bitter & Merrill, 1977). Although multielement taxonomy featured in these discussions, the uncertainty about gondolellid apparatuses prevented ir from playing a defìning role. Hence, some European workers continue to assign ali species to Gondole/la. Conversely, species formerly Text-fìg. 2 - Neogondolella mombergensis (Tatge, 1956). Sketch referred to Neogondolella have also been subdivided into diagrams of the discrete elements and part-elements numerous additional genera withour reference to named by Tatge and their interpretation as whole multielement composition (e.g. Kozur, 1989b). element components of the Neogondolella apparatus. MULTIELEMENT NEOGONDOLELLA 477
Gondolella mombergensis (P a) recognized that Prioniodella (Angulodus?) prionio- *Ozarkodina tortilis (P b) delloides was the posterior process of Hibbardella *Lonchodina mulleri (M, proximai) *Roundya magnidentata (Sa, proximal) (Roundya) magnidentata, although they did not discuss *Angulodus? prioniodelloides (Sa, distai) the implications of this interpretation (see below). The *Prioniodella decrescens (Sb l, distai) fragmented nature of many ramiform elements also Apatognathus longidentatus (Sbl, proximai) led Kozur & Mostler (1972) to group together Prioniodina insignis (Sb l, proximal) *Metalonchodina mediocris (Sb2, proximal) dissimilar elements, such as those they referred to Metalonchodina digitoformis (M or Sb2, proximai) Hindeodella (Metaprioniodus) suevica: their concept *Prioniodina latidentata (Se, proximai) embraced both the Scl and Sc2 of this paper plus *Prioniodella ctenoides (Se, distai) contiguous Se elements like the holotype of H. suevica, Metalonchodina cf. bidentata (Gunnei) (Sc2, proximal) which is not part of a Neogondolella species. Gen. et sp. indet. C (Scl, proximal) Gen. et sp. indet. B (Scl, proximal) Kozur (197 4, 1976) identified the multielement components of Neogondolella, and indeed gondolellids in generai, as comprising six form-species. These were PREVIOUS MULTIELEMENT RECONSTRUCTIONS (again, with current notation):
Huckriede (1958, p. 164) listed eight of Tatge's Gondole/la mombergensis Tatge (Pa) Ozarkodina tortilis Tatge (Pb) elements (shown above with asterisks) under the Enantiognathus ziegleri (Diebel) (Sbl) "conodonten-'Satz"' of Neogondolella navicula, and Prioniodina mulleri (Tatge) (M) thereby introduced the notion of a multielement Metaprioniodus latidentatus (Tatge) (Sc2) Triassic conodont species. His 'apparatus' consisted of Hibbardella magnidentata (Tatge) (Sa) the following (with current notation): Later, Kozur (1989b) used revised genera-based Gondole/la navicula Huckriede, 1958 (P a) descriptive terms for the appararus elements of Ozarkodina tortilis Tatge, 1956 (P b) gondolellids but did not provide an explicit notation Lonchodina mulleri Tatge, 19 56 (M) of homology. Whereas Kozur was clear o n his view of Roundya magnidentata Tatge, 1956 (Sa, proximal) the platform (Pa) and ozarkodiniform (Pb) couplet, Prioniodella prioniodelloides (Tatge, 1956) (Sa, distai) his cypridodelliform ( =prioniodiniform) element Prioniodella decrescens Tatge, 1956 (Sb l, part) Metalonchodina mediocris Tatge, 1956 (Sb2) apparently included both the M and Sb2 elements (in Lonchodina latidentata (Tatge, 1956) (Se, proximai) the sense of this paper), whilst the Se elements were Prioniodella ctenoides Tatge, 1956 (Se, distai) regarded as contiguous hindeodelliform elements. This Hindeodella triassica Muller, 1956 (Se) generalized notion of a 6-element gondolellid apparatus Apatognathus ziegleri Diebel, 1956 (Sbl) has generally persisted in the literature. The platform (Pa) element ofHuckriede's species- group, Neogondolella ( =Norigondolella) navicula, is now A NEW OCTOMEMBRATE MODEL known to be restricted to the Late Triassic (Norian) and has a somewhat different apparatus to that of Although the interpretation of Neogondolella Middle Triassic N mombergensis. Hence, Tatge's form- proposed herein rests on the study of a large number species should not be regarded as parts of N navicula. ofPermian and Triassic collections, i t is those from the Similarly, "Hindeodella triassica", originally described Mi dd! e Triassic that are particularly irnportant because by Muller (1956) from the Smithian of N evada, and that is the age of the type species of the genus. "Apatognathus ziegleri", originally described by Diebel Fortunately, the natura! assernblages of Neogondolella (1956) in association with Ladinian Budurovignathus frorn Switzerland are also Middle Triassic in age. Hence, mungoensis, are parts of other apparatuses. Neither the latter can be cornpared directly to both the North element is regarded as part of any Neogondolella American reconstructions and the type collections of apparatus. Neogondolella mombergensis from Gerrnany. Disjunct Huckriede (1958) also illustrateci examples of two Neogondolella collections frorn No nh America include ofTatge's species, Lonchodina latidentata (op. cit., pl. species that are broadly coeva! with N mombergensis. 10, fig. 32; pl. 11, fig. 42, 47) andPrioniodella decrescens Ali of these collections contain ramiforrn elernents that (op. cit., p!. 14, figs. 37, 38), that had bifurcate compare closely with Tatge's specimens and the sarne processes. Neither of Tatge's types showed such apparatus is clearly represented. This is contrary to the morphology, so, in making these an d other assignments, opinion ofBudurov & Sudar (1989) who introduced Huckriede pointed to the incomplete nature of many the new genus Pridaella for "Tethyan-Pacific" platform of Tatge's elements, a recurrent problem in Triassic gondolellids of this age. multielement taxonomy. This problem was also noted The constituent elements of Neogondolella are by Kozur & Mostler (1972) who illustrateci many described fully in the taxonomic part of this paper. For Triassic ramiform form-species. These authors purposes of the following discussion, the diagrammati c 478 M.]. ORCHARD, H. RIEBER
This paper P a Pb M Sa Sb1 Sb2 Se1 1Se2 Sweet, 1988 P a P a M Sa Pb Se Wardlaw & Grani, 1989 P a Pa!b M Scia Sb M Se Dzik, 1991 sp oz ne tr lo p l h i Hirseh, 1994 p P a Sa M Pb - Sb, Se von Bitter & Merrill, 1998 P a Pb M Sa Sb2 Se Sb1
T ab. l - Comparison oflocational notation applied to elements of Neogondolella and related taxa. The notation of Sweet (1988) and Wardlaw & Gran t (1989) are for the platform genus Neogondolella (Pa) and a separate ramiform genus referred to Xaniognathus an d/ or Cypridodella. The notation of Dzik (1991) was based o n Buaurovignathus ("Epigon- dolella"). In most cases, anterior and posterior parts of the Se (and Sa) elements have been regarded as contiguous. Text-fìg. 3 - Neogondolella mombergensis (Tatge, 1956). Sketch diagrams of the components of the apparatus. representation of the new 8-element model in Text- in the ozarkodinides (Purnell & Donoghue, op. cit.), fìg. 3 (and Pl. l) suffices. Of the eight different elements the order in which Neogondolella is included here. in collections of disjunct elements of Neogondolella, The assignment of particular conodont elements seven of them are sinistra! and dextral mirror-image of Neogondolella to a locational notation differs from pairs, which makes a total of 15 elements. The ramiform most previous interpretations, which are compared in basket of elements are assigned a notation that Tab . l. The natura! assemblages show convincingly that conforms with that utilized by Purnell & Donoghue the enantiognathiform element occupied an Sb l (1997, 1998), which reflects relative proximity of the position. They also show that a grodelliform or similar elements to the apparatus midline or axis. Hence the element occupied an Sb2 position. Interpretations of symmetrical and medial Sa element is bordered o n both elements assigned to both the Sa and Se positions also si d es by a sequence of Sb l , Sb2, Scl, an d Sc2 elements. differ radically from earlier ones. Each of these elements The other elements - Pa, Pb, and M - lie outside the appears to have consisted, at least through most later former series in relative positions identica! to that seen growth stages, of disjoined (or barely joined) proximal (biologically antero-ventral) an d distal (postero-dorsal) parts (Pls. 2, 3). The elements have not been recovered as contiguous elements (except possibly as very small A B c 19 Sa or Se growth stages) although functionally the parts must 1 P a P a 20 M M have been more or less aligned in the apparatus, as 2 P a P a 21 Se? Sb2 shown by the natura! assemblages. Were this not the 3 Pb Pb 22 Se? Sb2 case, the Neogondolella apparatus would consist of 20 4 Pb Pb 23 - Se1 elements, and a rather incongruent notation would be 5 Se Se 24 Se1 required. 6 - Se 25 Se 7 - Se 26 Se Sb1 8 Se 27 Se or Sb2 NATURAL ASSEMBLAGES 9 Se? SborSa 28 Se or Sb2 10 Se? Sb1 or Sb2 29 Se or Sb2 Although some Triassic gondolellids have been 11 Sb2 Sb1 30 Se2 regarded as platform-only, unimembrate apparatuses, 12 Sb2 Sb1 31 Se the natura! assemblages of Neogondolella in Middle 13 Sb1 Se 32 - Se or Sb2 Triassic bituminous shales ("Grenzbitumenzone") on 14 - Se 33 - Monte San Giorgio in Switzerland (Rieber, 1980; 15 Sa Sa 34 - Sb1 Orchard & Rieber, in prep.) leave no doubt about the 16 Sb1 Se 35 - Sb1 multielement nature of these particular Middle Triassic 17 - Se 36 Sa? species. Two Neogondolella species appear to be 18 - Se 37 represented within the currently available materia!, the more common being younger examples of the N. T ab. 2 - Comparison of the locational notation applied to elements comprising Neogo ndolella Assemblage l (Rieber, 1980; constricta group (P l. 4). The conodont assemblages, Column A) by von Bitter & Merrill (1998; Column B) although broken by intense compression of the shale and the present authors (Orchard & Rieber, in prep.; layers, are otherwise undisturbed and the present Column C). M.]. ORCHARD, H. RIEBER, MULTIELEMENT NEOGONDOLELLA P!. l
EXPLANATION OF PLATE l
Figs. 1-11 - Neogondolella sp. Reconstructed multielement apparatus based on Middle Anisian materia! from Nevada. Mosdy sample HB-105, except fìgs. 2, ll=HB-165, and fig. 6=HB-lll (see locality registry). Ali x80. Mosdy inner views of l=GSC 101780, dPa (upper); 2=GSC 101781, sPb; 3=GSC 101782, dM (image reversed); 4=GSC 101783, dSb1; 5=GSC 101784, dSb2; 6=GSC 101785, Se distal; 7=GSC 101786, sSc2 proximal (image reversed); 8=GSC 101787, dScl proximal; 9, 10=GSC 101788, Sa proximal (posterior, antero-lateral); ll=GSC 101789, Sa distal. 480 MJ ORCHARD, H. RIEBER
Po
Pb
Text-fig. 4 - Neogondolella mombergensis (Tatge, 1956). Exploded view of che component elements showing their approximate relative positions within an idealized dorso-ventrally flattened apparatus.
disposition of the elements dearly reflects the origi- they lay adjacent to the mediai Sa element. This rela- nai but collapsed apparatus structure. tive position appears true at the anterior end of the Rieber (1980) employed descriptive generic terms apparatus but that is because the true Sb l elements to identifY elements within the originai published (the enantiognathiform pair) lieto the posterior of the assemblage (hereafter Assemblage 1). He recognized Sa-Se anterior ramiform basket (Text-fìg. 4). The at least six or seven element types, and a minimum of enantiognathiform pair were referred to the Sb2 18 elements in ali. This induded pairs of platforms, position by von Bitter & Merrill (1998). In fact the ozarkodiniform, hindeodelliforms, enantiognathi- cusps of both the Sb l an d Sb2 elements li e further to forms, prioniodiniforms, and ?prioniodiniforms, as well the posterior (and more dorsally) than those of the Se as undetermined element types and unassigned and Sa elements, which is perhaps a unique feature of fragments. No elemental notation or architectural the gondolellaceans. interpretation was attempted on the single specimen Applying the numbers originally used by Rieber but certain anomalous features of the assemblage were (1980, fìg. l), element fragments 13, 14, 16-18 are noted. For example, the two pairs ofhindeodelliforms here interpreted as anterior parts of the 'hindeo- lacked convincing anterior processes, and in one case delliform' Se elements (5-8). Bar fragments 34 and 35 the denticulation of an apparent hindeodelliform are here interpreted as the inner latera! process of the pointed in the apposite direction to all the other dextral Sb l element which has been flipped back-to- element dentides. front (explaining the anomaly noted by Rieber, 1980), The new interpretati an ofAssemblage l differs from possibly aided by the collapse of the 'overlying' distai that presented recently byvon Bitter & Merrill (1998) part of the mediai Sa element. The equivalent process as shown in Tab. 2. The most conspicuous difference on the opposed Sbl element is thought to be concerns the identity of the Sb and Se elements. The represented by fragment 26, which was interpreted as elements regarded here as the anterior parts of Se a Se element by von Bitter & Merrill (1998). New elements were interpreted as a pair of complete Sb l illustrations and detailed analysis of Assemblage l are elements by von Bitter & Merrill (1998, fìg.l5) because provided by Orchard & Rieber (in prep.). M.]. ORCHARD, H. RIEBER, MULTIELEMENT NEOGONDOLELLA P!. 2
EXPLANATION OF PLATE 2
Figs. 1-11 - Neogondolella Scl and Se2 elements showing details of the proeess terminations. Note either minima! breakage, indieating narrow proeess attaehmenr (Figs. 2, 5, lO), or apparendy unbroken terminus suggesting funetional detaehment (Figs. 7, 9). Complete speeimens views are x80. Various loealities (see loeality registry) . Inner views of l, 2 (x320)=GSC l O1786, sSe2 proximal (sample HB-105); 3=GSC 101810, dSe2, juvenile with relatively long and eonriguous posterior proeess (sample FH-44); 4, 5 (x300)=GSC 101787, dScl proximal (sample HB-105); 6, 7 (x380)=GSC 101807, dSe2 proximal (sample D-12); 8, 9 (x600)=GSC 101811, Se distai (sample WAP-A6); lO (x600), ll=GSC 101812, Se distai (sample HB-185). 482 MJ ORCHARD, H. RJEBER
SUPRAGENERIC CLASSIFICATION Although they did no t regard the enantiognathiform element as the Pb element of Gondole/la, von Bitter & Previous classifications of Neogondolella have vari ed Merrill (1998, p. 128) nevertheless retained Gondole/la considerably. Lindstrom (1970) referred the genus to and its derivatives in the Prioniodinida. This was based the Gondolellidae, the single constituent familywithin on the demiculation of the S and M elements and their the superfamily Gondolellacea. This superfamily was interpretation of its ancestry in the Idioprioniodus- retained by the Treatise authors (Clark et al., 1981) Embsaygnathus lineage. Triassic gondolellids display a who distinguished within it two additional families, variety of demicles types and this criterion cannot be the Ellisonidae an d the Xaniognathidae. Neogondolella used to characterize them as prioniodinide. Both the was separated from Gondolella and placed in the Carboniferous roots of the gondolellids, and the nature Xaniognathidae. Neither Lindstrom (1970) nor Clark of prioniodinide apparatus remain enigmatic. Although et al. ( 1981) provided a diagnosis for members of the the multielemem apfaratus of Gondole/la as shown by Gondolellacea, other than to note that the normally von Bitter & Merril (1998) is not the same as that of multielement apparatus may have been reduced to a Neogondolella as interpreted here, both are clearly unimembrate one in some genera, as was thought to gondolellids. be the case with Neogondolella. Neogondolella is here regarded as an Ozarkodinide. Dzik (1976) included the Gondolellidae in a new Within that order, it shows similar complexity to suborder, the Ozarkodinina. Again, the specific features Devonian Palmatolepis, as noted by Dzik (1991). Apart of the family Gondolellidae were not discussed, but from the predominam 'anterior' growth of the platform, the salient features of the ozarkodinid apparatus were the presence of an enantiognathiform Sb l elemem listed (op. cit., p. 398). These features are essentially serves to distinguish the Gondolellacea. Furthermore, those of the superfamily Polygnathacea sensu the the Gondolellidae are characterized by the gondola- Treatise, which Sweet (1988) later subsumed in the shaped Pa elements. Subfamilial subdivision is Ozarkodinida. In contrast to Dzik, Sweet (1988) unwarramed at this time. included Neogondolella and other xaniognathids (recombined with Gondolella in the family Gondolellidae) into a new order, the Prioniodinida, SYSTEMATIC PALEONTOLOGY an amalgam of the superfamilies Gondolellacea and Hibbardellacea of the Treatise. The Prioniodinida Class CONODONTI Sweet, 1988 included multielement genera with "highly distinctive Order OzARKODINIDA Dzik, 1976 extensiform digyrate elements in the two P positions", Superfamily GoNDOLELLACEA Lindstrom, 1970 and morphologically intergradational elements with Family GoNDOLELLIDEA Lindstrom, 1970. generally discrete, peg-like demicles. The gondolellids were regarded as evolving from prioniodinides, like Genus NEOGONDOLELLA Bender & Stoppe!, 1965 Idioprioniodus, in the Late Carboniferous (Sweet, 1988, fig. 5.28). Centrai to this idea was the interpretation 1965 Neogondolella BENDER & STOPPEL, p. 343. of the enantiognathiform elements as occupants of the 1989 Pridaella n. gen. - BuoUROV & SUDAR, p. 250, 253. 1989b Clarkina n. gen. - KozuR, p. 428-9. Pb position. The natura! assemblages from Switzerland show this is not the case. Type species- Neogondolella mombergemis Tatge 1956 Dzik (1991, p. 315) maintained both the family (seeText-fig. l, this paper). Gondolellidae and the superfamily Gondolellacea as p art of the order Ozarkodinida. Hirsch (1994b), Diagnosis - Neogondolella bore an octomembrate followed Dzik's suprageneric classification of apparatus consisting of a total of 15 elements (7 pairs Neogondolella, but in addition he erected two new plus symmetrical Sa): Pa is segminiplanate (neo- subfamilies, the Neogondolellinae and Gladigon- gondolelliform), Pb is angulate (xaniognathiform), Sa dolellinae. The former, encompassing ali Triassic taxa is alate (hibbardelliform), Sb l is breviform digyrate with pectiniform platform elements other than (enantiognathiform), Sb2 is dolabrate or similar Gladigondolella, was regarded as possessing a generalized (grodelliform, cypridodelliform), Scl resembles apparatus pian curiously combining both ozarkodinide tertiopedate (cf. hindeodelliform with bifurcate anterior and prioniodinide attributes. process), Sc2 is bipennate (cf. hindeodelliform), and
EXPLANATION OF PLATE 3
Figs. 1-9 - Neogondolella elements. Distai parts ofSa elements from N evada and China showing unbroken process terminations. Complete specimens views are x80. l , 2 (x400)=GSC 101813, sample HB-165; 3, 4 (x386)=GSC 101814, sample D-6; 5, 6, 7(x250)= GSC 101800, sample HB-519; 8 (x 100), 9=GSC 101789, sample HB-165. M.]. ORCHARD, H. RIEBER, MULTIELEMENT NEOGONDOLELLA P!. 3 484 M.]. ORCHARD, H. RIEBER
M is breviform digyrate (cypridodelliform). The Sa process, and a commonly disconnected posterior pro- and Se elements commonly occur as disjointed ante- cess. lt differs from the Sc2 element only in possess- rior and posterior parts. ing a bifurcate anterior process: the third "process" is developed on the outer side of the more strongly Description - Pa element: segminiplanate with inturned anterior process about mid-way along its variably upturned, generally unornamented platform length; the two anterior-most branches that result ledges developed along part or ali the length of the are subequal in size but are asymmetrically arranged, centrai blade-carina-cusp axis, which is variably elevateci unlike in the tertiopedate Sa element. and fused. The lower side features a variably developed Sc2 element: bipennate and commonly occurring double pit located near the posterior end of a zone of in two parts. The proximal part includes two processes: recessive lamellae that outline a narrow to broad, a down-arched and inwardly turned anterior process, medially grooved keel. and a short posterior process. The cusp is the largest of Pb element: angulate with a long anterior process the denticles, and is followed anteriorly by severa! and a shorter, lower, and variably inturned posterior smaller and then higher denticles which forma convex process bearing denticles that are often smaller. crest declining in size progressively toward the distai M element: breviform digyrate (cypridodelliform) end of the process. The preserved posteri or process bears element with two markedly un equa! processes, o ne long up to 6 relatively small denticles on a short bar that is and gendy arched and a second short and anteriorly broken or narrowly terminated. A second, distai part flexed. The long, strongly differentiated cusp is inclined of the Se elements is a long and narrow, regularly perpendicular to the piane of the processes. The shorter denticulate posterior bar that is often broken into process bears up to 6 small denticles. smaller fragments. Sa element: alate with two down-arched latera! processes that meet a t the large mediai cusp or a dentici e Comparisons - The apparatus described herein is immediately to its anterior to forma right-angle with recognized in many, bur no t ali taxa currendy grouped the posterior process. The latter is short in ali available as gondolellids. The multielement configuration of specimens, bearing a maximum of 8 small denticles. Gondole !la has recendy been summarized by von Bitter As interpreted here, the contiguous posterior process & M erri!! (1998). Although these authors regarded the is supplemented by a large 'detached' distai process (the Neogondolella natura! assemblage as a template for element Angulodus? prioniodelloides Tatge sensu formo). Gondolella, the morphology of severa! individuai This element has denticles that increase in size towards elements of Neogondolella as described herein appears the posteri or o ne third of the process an d then decrease to differ sufficiently to distinguish the two genera. For in size beyond, where the process is often strongly down example, the M element of Gondolella has a strongly turned. The element is commonly sinuous in upper expanded inner basai cavity and keel; the Sa element view, particularly in its centrai part (Plate 3). has no distai part like that of Neogondolella; there is no Sbl element: strongly bent, digyrate with one bifurcate Se element; and the similarity between the relatively strongly developed 'dee p' anterior process an d Pb and Se elements in Gondolella is not seen in the a weakly developed 'thin' and arcuate latera! process younger genus. Therefore, Triassic species should no that at first is directed toward the anterior and then is longer be assigned to Gondolella. laterally flexed distally. The large, high cusp stands at The apparatus of Mesogondolella Kozur is not fully the junction of the two dissimilar but equally long described but it apparently also lacks a bifurcate Se processes and projects posteriorly. The larger process element. Kozur (1989b, _p. 428, p!. 3, figs. 3, 5) noted has denticles that form a high convex crest distally, that the cypridodelliform elements (apparent!y become smaller towards process mid-length (where the including both M and Sb2) have a costa along the element commonly breaks), and then become larger length of the cusp, as in Gondolella M elements; this towards the cusp. The smaller process is somewhat feature is also seen in the Sb2 elements of some sinuous, very thin, and fragile; it is rarely preserved Neogondolella species. The V-shaped basai configuration intact, commonly breaking dose to its junction with of Mesogondolella appears to provide a reliable the cusp where its orientation changes. distinction from Neogondolella. Sb2 element: dolobrate or similar (typically The apparatus of Mi dd! e Permian ]inogondolella is grodelliform) with one long anterior process that bears essentially the same as that of Neogondolella, although regular denticulation that may be higher distally. The most of the Pa elements of the former have distinctive longest dentici e of the element is the apiea! cusp, which platform ornament. projects posteriorly and has a convex posterior edge. There are no significant differences between the ap- The basai margin of the element is commonly evenly paratuses of Neogondolella and Late Permian-basal Tri- curved but in some species there is a small secondary assic species assigned to Clarkina (P!. 5). A primary fea- process bearing a few small denticles. Such elements ture cited (Kozur, 1989b, p. 428-9) as diagnostic of are gradational to the M element. Clarkina - the presence of a free biade in the Pa element Sci element: 'tertiopedate' with a bifid anterior - is not characteristic of the younger species assigned to M.]. ORCHARD, H. RIEBER, MULTIELEMENT NEOGONDOLELLA P!. 4
EXPLANATION OF PLATE 4
Figs. 1-12 - Neogondolella ex gr. constricta (Mosher & Clark 1965). Reconstructed multielement apparatus based on Upper Anisian materia! from Fossi! Hill, Nevada. Mosdy from sample HB-519, except fig. 3, 10=FH-50. Ali are x80. Mosdy inner views of 1=GSC 101790, sPa; 2=GSC 101791, dPb; 3=GSC 101792, sM; 4, 5=GSC 101793, 101794 dSb1 proximal, distai; 6=GSC 101795, dSb2; 7=GSC 101796, dScl; 8=GSC 101797, sSc2 (image reversed); 9, 10=GSC 101 798, GSC 101 799, Sa proximal (2 specimens, posterior, anrero-lateral); 11, 12=GSC 101800, Sa distai (upper, latera!).
that genus (e.g. Orchard & Krystyn, 1998), but is seen below). Neogondolella-like platform species occurring in some species of Neogondolelfa. These two genera have within the higher Scythian have been referred to other mainly been distinguished on the basis of stratigraphic form-genera, namely Srythogondolelfa Kozur, Kozurelfa separation, i.e. Cfarkina allegedly becarne extinct in the Budurov & Sudar (=Pseudogondolelfa, =Chengyuania), basal Triassic whereas Neogondolelfa is believed to have Chiose/fa Kozur, and Paragondolelfa Mosher. The appa- evolved from Neospathodus in the Middle Triassic (see ratus of these genera await description, an exercise be- M.]. ORCHARD, H. RIEBER, MULTIELEMENT NEOGONDOLELLA Pl. 5
EXPLANATION OF PLATE 5
Fig. 1-11 - Neogondolella ex gr. subcarinata Sweet 1973. Reconstructed multielement apparatus based on materiai from the upper Changshingian (sample D-12) at Meishan, China. All are x80. Mosdy inner views of 1=GSC 101801, dPa, (upper); 2=GSC 101802, dPb; 3=GSC 101803, dM; 4=GSC 101804, sSb2; 5=GSC 101805, sSb1; 6, 7=GSC 101806, Sa distai (!arerai, upper); 8=GSC 101807, dSc2; 9=GSC 101808?, Scl; 10, 11=GSC 101809, Sa (anrerior, anrero-laterai).
yond the scope of the present paper. For now, i t can be The apparatus of Gladigondolella is quite differ- stated that some (including Neospathodus) are different ent from Neogondolella, and the genus should be as- from Neogondolella, whereas others, like Clarkina, are signed to a separate family of the Gondolellacea. Ali regarded as synonyms. elements have markedly discrete denticles, and the The distinction between Neogondolella and other Pa, Sb l an d M elements all differ from those of Middle and Late Triassic multielement gondolellids is Neogondolella. Revised classification is also required also in need of resolution. The re-emergence of for polyphyletic "Neospathodus': and Middle-Upper neogondolelliform-bearing taxa in the Norian may have Norian Cypridodella (=Epigondolella partim, Mockina), its roots in species presendy assigned to Metapolygnathus which contain contiguous and non-birfcurcate, (Orchard, 199la). The genus Norigondolella Kozur has bipennate Se elements and alate Sa elements. Lower been introduced for these species, which have a Pb Norian Epigondolella, as typified by E. triangularis, element with a distinctive down-arched posterior pro- has a similar apparatus to Neogondolella but appar- cess, and an M element with a uniquely broad cusp. endy lacks bifurcate Sc2 elements. MULTIELEMENT NEOGONDOLELLA 487
Remarks - A particularly distinctive feature of the cific variability in mid Triassic species, including Neogondolella apparatus is the frequent occurrence of Neogondolella mombergensis. Sa and Se elements in two parts. This phenomenon may be more common in larger specimens, but in the Origins ofNeogondolella- In the case of Neogon- available materia! there are no completely contiguous dolella sensu stricto, it has been argued that the origin elements of any size. This is not the same phenomenon of its type species, N mombergensis, lies in the basai as described by Donoghue (1998) whereby discrete Middle Triassic Chiosella timorensis, which itself is centres of early growth stages coalesce as they enlarge. thought to have evolved from a species presently Rather, the elements may either start as single entities assigned to Neospathodus (Bender, 1970; Kozur, 1989a). but become disconnected as they grow, or separate parts Older examples of elements formerly assigned to may have existed from an early growth stage. The Neogondolella have therefore been referred to separate process termini of Se and Sa elements often appear genera such as Clarkina, Paragondolella and others complete (Pls. 2, 3) but this may result from subsequent noted above. However, typical Neogondolella appears overgrowth, such as that which occurs when damaged prior to Chiosella. Furthermore, Spathian Neospathodus denticles are repaired. Well preserved 'posterior has a different apparatus to both Neogondolella and processes' of the Sa elements show no breakage and Chiosella. The ancestors of Neogondolella are therefore must have been growing as discrete elements, at least regarded as lying within Permian complex presendy prior to death. The effect of having separate anterior assigned to Mesogondolella and]inogondolella. and posterior element parts may have been to impart greater flexibility to the apparatus, and perhaps some advantage to this pelagic genus. ACKNOWLEDGEMENTS The relative position of the Scl and Sc2 elements is uncertain. Although Orchard (1998) assumed a Some Anisian conodonts from Nevada were recovered from matrix sarnples collected by H. Bucher (U. Lyon). HillaryTaylor 'better fit' would have occurred with the bifurcate (GSC, Vancouver) is thanked for help with the figure and plate element on the outer side, new data from the natura! preparation. Geological Survey ofCanada Contriburion Number assemblages suggest that the anterior end of the 1999012. tertiopedate element probably occupied a position adjacent to the Sa element (Orchard & Rieber, in prep.). APPENDIX l The position of the Sb l an d Sb2 elements differs from the Sa and Se elements in that their apical cusps LOCALITY Rf.GISTRY are situated in a more posterior position. Similarly, the Sample HB-105 = GSC loc. C-176331; Taylor Zone, M. inner latera! processes of the Sb l pair an d the posterior Anisian, Favret Canyon, Nevada process of the Sa element form a third focal point in a Sample HB-111 = GSC loc. C-176333; Shoshonensis Zone, M. relatively ventral position within the apparatus Anisian, as 105. (Orchard & Rieber, in prep.). These multiple focal Sample HB-165 = GSC loc. C-176342; as 105. Sarnple HB-185 = GSC loc. C-176384; as 105. points represent an atypical condition for ozarkodinide Sample HB-519 = GSC loc. C-201581; Occidentalis Zone, U. apparatuses, although the apparatus of some Devonian Anisian, Saurian Hill, Nevada. Palmatolepis may have been similar. As described, the Sarnple FH-44 = GSC loc. C-300225; Meeki Zone, U. Anisian, apparatus pian of Neogondolella is regarded as typical Fossi! Hill, Nevada. of gondolellaceans. Sample FH-50 = GSC loc. C-300229; Occidenralis Zone, as 44. The Sa element of Neogondolella shows some Sample D-6 = GSC loc. C-158616; middle Changshingian, variation through the range of the genus (Orchard & Meishan, China. Rieber, 1996). Ali late Paleozoic species an d most that Sample D-12 = GSC loc. C-158625; upper Changshingian, are Middle Anisian or older have an Sa element in Meishan, China. Sample WAP-A6 =GSC loc. C-303533; Ladinian, Wapiti Lake, which the two antero-lateral processes meet at the cusp B.C. (Pls. l, 5), whereas in younger species the processes generally meet at a denticle anterior of the cusp (Pl. 4). Both Tatge (1956) and Huckriede (1958) included REFERENCES both variants of Sa element in Roundya magnidentata, BENDER, H., 1970, Zur Gliederung der Mediterranen Trias II. Die although Tatge's holotype was of the latter variety. Conodontenchronologie der Medeterranen Trias: Annales North American collections of Neogondolella from the Geologiques des Pays Helleniques,l9: 465-540, 5 pls. Upper Anisian also contain both varieties of this Sa BENDER, H. & STOPPEL, D ., 1965, Perm-conodonten: Geologisches element. The difference in Sa elements, which formed Jahrburg, 82: 331-364, 3 pls. BRJGGS, D.E.G., CLARKSO N, E.N.K. &ALDRJDGE, R.J ., 1983, The a basis of the distinction between Xaniognathus and conodont animal: Lethaia, 16: 1-14. Cypridodella sensu Sweet (1988), is here regarded as BuouROV, K.J. & SuDAR, M.N., 1989, New conodont taxa from of specific or lesser rank. lt may constitute intraspe- the Middle Triassic. Geology of Himalayas - Palaeontology, 488 M.j ORCHARD, H RIEBER
Stratigraphy and Structure: Contributions to Himalayan 0RCHARD, M.]. & KRYSTYN, L. , 1998, Conodonts of che lowermost Geology, 4: 250-254, 2 pls. Triassic of Spiri, and new zonation based on Neogondolella CLARK, D.L., SWEET, W.C., BERGSTROM, S.M., l