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Scolopodus species originally described by Pander. A. Scolopodus striatus Pander, 1856, in lateral (A 1 , A 4 ), posterior (A 2 ), and anterior (A 3 ) views; A 5 , cross section of the base (Pander 1856: table 2, fig. 8a-d, table A, fig. 5f). B. Scolopodus semicostatus Pander, 1856, in lateral views (B 1 , B 2 ); B 3 , cross section of the base (Pander 1856: table 2, fig. 4a, b, table A, fig. 5e). C. Scolopodus sublaevis Pander, 1856, in lateral (C 1 ) and posterior (C 2 ) views; C 3 , cross section of the base (Pander 1856: table 2, fig. 3a, b, table A, fig. 5e). D. Scolopodus quadratus Pander, 1856, in lateral (D 1 , D 2 ), posterior (D 3 ), and lower (D 4 ) views; D 5 , cross section of the base (Pander 1856: table 2, fig. 6a-c, table A, fig. 5e). E. Scolopodus costatus Pander, 1856, in lateral (E 1 , E 4 ), posterior (E 2 ), and anterior (E 3 ) views; E 5 , cross section of the base (Pander 1856: table 2, fig. 7a-d, table A, fig. 5e). F. Scolopodus aequilateralis Pander, 1856, in lateral (F 1 , posterior (F 2 ), and anterior (F 3 ) views; F 4 , cross section of the base (Pander 1856: table 2, fig. 5a-c, table A, fig. 5e).
Source publication
The Lower Ordovician conodont Scolopodus striatus Pander, 1856 (= Scolopodus rex Lindström, 1955) has an apparatus composed of five element morphotypes: acontiodiform, subrounded, compressed paltodiform, paltodiform, and scandodiform. The identification of the morphotypes is based on the general asymmetry of elements and shape of their bases. The e...
Contexts in source publication
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... the six de− scribed by Pander are characterised by costae starting just from the edge of the basal margins, but none of the com− plete Scolopodus elements in the available collection have costae that start from this position; all of them have a small smooth surface or low rim on the base of the elements. Only two of Pander's species (S. striatus, Fig. 5A and S. sub− laevis, Fig. 5C) demonstrate the costae starting slightly above the basal ...
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... are characterised by costae starting just from the edge of the basal margins, but none of the com− plete Scolopodus elements in the available collection have costae that start from this position; all of them have a small smooth surface or low rim on the base of the elements. Only two of Pander's species (S. striatus, Fig. 5A and S. sub− laevis, Fig. 5C) demonstrate the costae starting slightly above the basal ...
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... translation by Fåhraeus 1982: 19). As noticed by Fåhraeus (1982), there is a disagreement between the illustration and the description of this taxon. The ele− ments are described as asymmetrical, while the drawings indicate symmetry, with the costate posterior margin and lateral margins bearing single grooves. According to Pan− der's drawings (Fig. 5C), S. sublaevis has a relatively low base and strongly recurved cusp that is typical for several Scolopodus elements: acontiodiform elements, some vari− eties of the compressed paltodiform elements and paltodi− form elements (Fig. 6B-D). However, the grooves on the lateral sides that were described and illustrated by Pander are not ...
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... striatus Pander, 1856.-S. striatus was origi− nally described as having: "Oval cross−section. The convex margin is formed by a arched surface, whilst the rest of the entire tooth is covered with fine costae along its entire length." (Pander 1856: 26, original translation of Fåhraeus 1982: 20). S. striatus Pander, 1856 sensu formae (Fig. 5A 1 , A 2 ) appears to be more easily recognised when compared with the other species of Scolopodus described by Pander. This fact was commented on by Serpagli (1974), who no− ticed the general similarity of Scolopodus elements from Precordilleran Argentina with S. striatus Pander, 1856 s.f. Fåhraeus identified S. striatus s.f. among the ...
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... striatus s.f. among the compressed paltodiform elements and placed it as near−symmetrical ele− ments within the apparatus of S. guadratus (Fåhraeus, 1982). S. striatus s.f. is the only one of Pander's Scolopodus species whose drawing and description agrees well with the asym− metrical short−based varieties of the compressed paltodiform elements (Figs. 5A, 7M, O, P). Pander 1856: table 2, fig. 8a-d, table A, fig. 5f). B. Scolopodus semicostatus Pander, 1856, in lateral views (B 1 , B 2 ); B 3 , cross section of the base (Pander 1856: table 2, fig. 4a, b, table A, fig. 5e). C. Scolopodus sublaevis Pander, 1856, in lateral (C 1 ) and posterior (C 2 ) views; C 3 , cross section of the base ...
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... elements and placed it as near−symmetrical ele− ments within the apparatus of S. guadratus (Fåhraeus, 1982). S. striatus s.f. is the only one of Pander's Scolopodus species whose drawing and description agrees well with the asym− metrical short−based varieties of the compressed paltodiform elements (Figs. 5A, 7M, O, P). Pander 1856: table 2, fig. 8a-d, table A, fig. 5f). B. Scolopodus semicostatus Pander, 1856, in lateral views (B 1 , B 2 ); B 3 , cross section of the base (Pander 1856: table 2, fig. 4a, b, table A, fig. 5e). C. Scolopodus sublaevis Pander, 1856, in lateral (C 1 ) and posterior (C 2 ) views; C 3 , cross section of the base (Pander 1856: table 2, fig. 3a, b, table A, fig. 5e fig. ...
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... Scolopodus species whose drawing and description agrees well with the asym− metrical short−based varieties of the compressed paltodiform elements (Figs. 5A, 7M, O, P). Pander 1856: table 2, fig. 8a-d, table A, fig. 5f). B. Scolopodus semicostatus Pander, 1856, in lateral views (B 1 , B 2 ); B 3 , cross section of the base (Pander 1856: table 2, fig. 4a, b, table A, fig. 5e). C. Scolopodus sublaevis Pander, 1856, in lateral (C 1 ) and posterior (C 2 ) views; C 3 , cross section of the base (Pander 1856: table 2, fig. 3a, b, table A, fig. 5e fig. 6a-c, table A, fig. 5e). E. Scolopodus costatus Pander, 1856, in lateral (E 1 , E 4 ), posterior (E 2 ), and anterior (E 3 ) views; E 5 , cross section of the ...
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... table A, fig. 5f). B. Scolopodus semicostatus Pander, 1856, in lateral views (B 1 , B 2 ); B 3 , cross section of the base (Pander 1856: table 2, fig. 4a, b, table A, fig. 5e). C. Scolopodus sublaevis Pander, 1856, in lateral (C 1 ) and posterior (C 2 ) views; C 3 , cross section of the base (Pander 1856: table 2, fig. 3a, b, table A, fig. 5e fig. 6a-c, table A, fig. 5e). E. Scolopodus costatus Pander, 1856, in lateral (E 1 , E 4 ), posterior (E 2 ), and anterior (E 3 ) views; E 5 , cross section of the base (Pander 1856: table 2, fig. 7a-d, table A, fig. 5e). F. Scolopodus aequilateralis Pander, 1856, in lateral (F 1 , posterior (F 2 ), and anterior (F 3 ) views; F 4 , cross section of the base ...
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... sublaevis Pander, 1856, in lateral (C 1 ) and posterior (C 2 ) views; C 3 , cross section of the base (Pander 1856: table 2, fig. 3a, b, table A, fig. 5e fig. 6a-c, table A, fig. 5e). E. Scolopodus costatus Pander, 1856, in lateral (E 1 , E 4 ), posterior (E 2 ), and anterior (E 3 ) views; E 5 , cross section of the base (Pander 1856: table 2, fig. 7a-d, table A, fig. 5e). F. Scolopodus aequilateralis Pander, 1856, in lateral (F 1 , posterior (F 2 ), and anterior (F 3 ) views; F 4 , cross section of the base (Pander 1856: table 2, fig. 5a-c, table A, fig. ...
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... costatus Pander, 1856, in lateral (E 1 , E 4 ), posterior (E 2 ), and anterior (E 3 ) views; E 5 , cross section of the base (Pander 1856: table 2, fig. 7a-d, table A, fig. 5e). F. Scolopodus aequilateralis Pander, 1856, in lateral (F 1 , posterior (F 2 ), and anterior (F 3 ) views; F 4 , cross section of the base (Pander 1856: table 2, fig. 5a-c, table A, fig. ...
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... inent carina (= costa) runs from the base to the tip, dividing the smooth surface into two equal halves. The opposite lat− eral surface is ornamented with four costae, which are sepa− rated from each other by five−six furrows." (Pander 1856(Pander : 26, original translation of Fåhraeus 1982. The element of S. semicostatus illustrated by Pander (Fig. 5B) bears little re− semblance to any available Scolopodus elements, although it is generally similar to some rare varieties of paltodiform or compressed paltodiform elements (Fig. 6C). The latter ele− ments, however, are usually characterised by additional tiny costae on the outer side. Fåhraeus (1982) did not recognise this species in ...
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... as follows: "The cross−section is elongated rectangular. The convex margin of the tooth is formed by a parallel−sided smooth outward arched surface, the concave (margin) by a prominent costa. Two similar costae run on the lateral surfaces from the base to the tip." (Pander 1856(Pander : 26, original translation of Fåhraeus 1982. S. aequilateralis (Fig. 5F) is similar in general shape to the subrounded Scolopodus elements (Fig. 8H, I) as well as to the long−based varieties of compressed paltodiform elements (Figs. 6E, 7D). However, the basal rim that characterises the elements figured by Pander is lacking. A small number of costae is typical for the juvenile forms of the subrounded ele− ...
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... mentioned before, the main difference between S. quadratus, as well as the other three Scolopodus species of Pander (1856) with available elements, is the absence of smooth basal rims on elements figured by Pander (Fig. 5D). Other morphological characters of S. quadratus, such as square cross−section, costate lateral sides and relatively low base, are characteristic of the acontiodiform elements. How− ever, they are not similar to S. quadratus in general shape. The elements of S. costatus illustrated by Pander do not show any extension of the base whereas ...
Citations
... Protopanderodus nogamii ranges from the Jumudontus gananda to Phragmodus undatus-Tasmanognathus careyi zones in the shelf-marine succession of the Australasia standard (Zhen et al., 2003(Zhen et al., , 2010(Zhen et al., , 2015Zhen and Percival, 2017;Zhen, 2021). Scolopodus striatus ranges from the Paroistodus proteus to Baltoniodus norrlandicus zones in the North Atlantic standard (Tolmacheva, 2006). Triangulodus larapintinensis ranges from the Reutterodus andinus to Histiodella holodentata zones in the North American Midcontinent standard (Agematsu et al., 2008a). ...
During the Ordovician period, Western Thailand was part of the Sibumasu Block. Most studies on Ordovician conodonts in this region have focused on the Thong Pha Phum area, where the Triangulodus larapintinensis Range Zone of Floian and Aurilobodus leptosomatus Range Zone of Darriwilian have been documented.
In this study, conodont samples were collected from two sections in the Ban Tha Kradan area of Western Thailand: from the Wat Mong Krathae (WMK) and Nautiloid Site Geosite (NSG) sections. In total 24 conodont samples were collected from the WMK section, all from the Tha Manao Formation characterized here by laminated and cross-bedded thin- to medium-bedded limestones. From the NSG section only three conodont samples were processed, one of them from the Tha Manao Formation and two from the revised Pa Kae Formation, which consists of thin- to medium-bedded laminated limestones and stylolitic limestones.
Eleven Ordovician conodont species representing nine genera are documented and illustrated from the Ban Tha Kradan area for the first time. The species identified are Baltoniodus cf. alobatus (Bergström), Cornuodus longibasis (Lindström), Drepanoistodus pitjanti (Cooper), Drepanoistodus cf. pitjanti sensu (Zhen et al. 2021), Erraticodon patu (Cooper), Protopanderodus nogamii (Lee), Plectodina sp., Scabbardella altipes (Henningsmoen), Scolopodus striatus (Pander), Triangulodus larapintinensis (Crespin), and Triangulodus sp. In the WMK section, the Scolopodus striatus Assemblage Zone can be recognized in the Tha Manao Formation. Roughly, it corresponds to the eponymous assemblage zone in the northwestern peninsular Malaysia.
Furthermore, the upper part of the Tha Manao Formation in the NSG section as identified earlier has been revised and assigned to the Pa Kae Formation, based on the lithostratigraphic features. Considering the occurrences of cephalopod Sinoceras chinense (Foord) and conodont Baltoniodus cf. alobatus, as well as on the recognition of the Guttenberg Carbon Isotope Excursion (GICE) in the lowermost part of the formation, the revised Pa Kae Formation in Western Thailand has a similar temporal range as that of the Pa Kae Formation in the southern peninsular Thailand. Thus, the Tha Manao Formation in Western Thailand is assigned to the upper Floian to Darriwilian, and the conformably overlying Pa Kae Formation to the Sandbianâlower Katian.
... A group of scolopodontid species that lack multicostate elements have been variably assigned to either Scolopodus, Pander, 1856, Semiacontiodus Miller, 1969or Staufferella Sweet et al., 1975 Scolopodus is now restricted to multicostate species (Tolmacheva 2006) and both Semiacontiodus and Staufferella include acostate to tricostate elements. Semiacontiodus might have evolved from Teridontus in the latest Cambrian (L€ ofgren 1999b) and subsequently give rise to Scolopodus and several other major coniform clades with thick hyaline walls and a shallow basal cavity in the Ordovician. ...
The conodonts documented by Watson form one of the best-known middle Darriwilian faunas from Australia. The present contribution is based on the re-examination of this material. Thirty-one conodont species from the subsurface Goldwyer and Nita formations of the Santalum 1 A drill core section of the Canning Basin, Western Australia are documented and described, including two new species, Belodina watsoni sp. nov. and Scalpellodus percivali sp. nov. The revised fauna is characterized by diagnostic species, namely Histiodella holodentata, Histiodella triangularis, and Eoplacognathus pseudoplanus. It provides compelling evidence to correlate this stratigraphic interval
represented by the upper part of the Goldwyer and overlying Nita formations in the Santalum 1 A drill core section to the Histiodella holodentata or Eoplacognathus pseudoplanus biozones of middle Darriwilian age. However, in the Canning Basin, the faunal change signaled by the disappearance of H. holodentata and appearance of E. pseudoplanus reflects shifting of depositional settings from intermediate to outer shelf environments to shallower inner shelf conditions, coinciding with a regional regression event. New taxonomic data also enable more precise regional correlation of middle Darriwilian rocks across the Canning Basin and the Amadeus and Georgina
basins in northern-central Australia.
... After a long period of 'stasis', several new and important Early and Middle Ordovician genera, such as Falodus, Gothodus, Oepikodus, Oneotodus, Paracordylodus, Scandodus, Tetraprioniodus, Trapezognathus, and Lenodus were added to the Baltica fauna by Lindström (1955Lindström ( , 1960, Wolska (1961), Bergström and Gee (1962), Sergeeva (1963aSergeeva ( , 1963bSergeeva ( , 1964Sergeeva ( , 1966, Fåhraeus (1966), Viira (1966Viira ( , 1967Viira ( , 1974. These early papers were using form-element taxonomy and the following newer to recent papers have focused mainly on systematic revisions and transferred many of the classic form-element genera and species into modern multielement taxonomy (e.g., Bergström, 1971;Lindström, 1971a;van Wamel, 1974;Dzik, 1976Dzik, , 1994Löfgren, 1978;Bednarczyk, 1979Bednarczyk, , 1998Olgun, 1987;Stouge, 1996, 1997;Stouge and Bagnoli, 1988Löfgren et al., 1999;Rasmussen, 2001;Löfgren and Zhang, 2003;Tolmacheva, 2006;Löfgren and Tolmacheva, 2008). ...
... The multielement apparatus of Scolopodontidae is composed of costate to multicostate, nongeniculate, symmetrical to asymmetrical, hyaline coniform elements. The genus Scolopodus Pander has been revised by Tolmacheva (2006); based on this description and multielement reconstruction then the only genus that can be safely referred to the family is Scolopodus Pander. Löfgren (1999) described the species Semiacontiodus cornuformis Sergeeva and referred it to Scolopodontidae as a related species. ...
The stratigraphic distributions, taxonomy, diversity, evolutionary lineages and events of late Cambrian to Middle Ordovician euconodonts of Baltica are briefly reviewed and re-evaluated. The euconodonts of the late Furongian (Stage 10, late Cambrian) to Middle Ordovician successions of Baltica record innovation, immigration and two invasions of short duration and one major extinction. The innovation event with an origin on Baltica is the rise of the Proconodontus serratus lineage in the late Furongian (Stage 10). The immigration events comprise the Cordylodus immigration to Baltoscandia in latest Cambrian and this phylogenetic lineage persisted to mid Tremadocian (Early Ordovician) and vanished at the global mid-Tremadocian extinction event. The late Floian – basal Dapingian transition is a significant event on Baltica. It is characterized by the immigration of the important genera Baltoniodus and Microzarkodina and when first arrived these taxa stayed for a long period on the Baltica palaeocontinent forming evolutionary lineages. The basal Darriwilian immigration event by the genus Lenodus and coeval prominent sea-level lowstand were caused by a short global icehouse stage related to the expansion of the polar ice sheets. The extinction event caused the disappearance of the characteristic Cordylodus fauna. Most events are related to change of the palaeoclimate due to the movement of the Baltica palaecontinent and associated eustatic sea level changes. However, the cause of the global early Tremadocian extinction event is not yet completely clear and remains unsolved. Perhaps abrupt and significant palaeoceanographic changes on global scale i.e. plate tectonic movements causing sudden change of ocean currents and climate from warm to cold were the cause for this significant extinction in the Early Ordovician.
... However, they are present in small numbers, have parts of the bases and cusps missing and are too thermally mature for the white matter and extent of internal cavities to be discernible. The compressed paltodiform element (Fig. 7y) bears a resemblance to Scolopodus striatus as reconstructed by Tolmacheva (2006), but is considered closer to ?Tropodus (TY Tolmacheva, pers. comm. ...
... The other coniforms with striated bases (Fig. 7y, w, aa) also suggest a possible Tremadocian age, although we have loosely identified them as either Scolopodus or Tropodus and Semiacontiodus. Scolopodus striatus has been found in the Lower Ordovician from the Paroistodus proteus Zone to the Microzarkodina parva Zone (Löfgren, 1978;Stouge & Bagnoli, 1990;Tolmacheva, 2006). Older examples of Scolopodus, for example S. aff. ...
The Middle Shale Member of the Amdeh Formation is interpreted to be of Early Ordovician age based on its trace fossils, stratigraphic context and a newly discovered fauna of conodonts. The member abruptly overlies the Lower Quartzite Member, which may be Early Cambrian, and passes gradationally-upward into the Upper Quartzite Member, which is probably Early–Middle Ordovician. The 542.5 m thick Middle Shale Member can be divided into two parts: a shaly lower part, and a sandy upper part that contains an influx of heavy minerals. Bioturbation by marine trace fossils is one of the most obvious characteristics of the member. The shales and sandstones are interpreted to be of Cruziana and Skolithos ichnofacies and represent shallow-marine shelf, shoreface, beach and coastal deposits. Sparse shelly fossils occur in the sandy upper part, principally bivalves, inarticulate brachiopods, ostracods and conodonts. The small assemblage of conodonts includes elements interpreted to be Tremadocian ( Tetraprioniodus , Drepanoistodus , Drepanodus , Scolopodus , ? Tropodus , Semiacontiodus and Teridontus ), and others which may be Floian or ancestral forms of Floian taxa (Balognathidae gen. et sp. indet. A & B and aff. Erraticodon ). No acritarchs have been recovered, probably due to high temperatures experienced during burial to >6 km. It is likely that the Middle Shale Member is the seaward equivalent of the Mabrouk and Barakat formations, and an outcrop gamma-ray log supports such a correlation. The trace fossils, sedimentology, conodont fauna and the general lack of macrofossils are in keeping with the regional Tremadocian–Floian of the Arabian margin of Gondwana.
... krummi (Lehnert, 1995) supports a position of the material in the Tremadocian-Floian transition. Tolmacheva (2006) showed that the typical costate elements of Scolopodus are recorded in the upper P. proteus Zone for the first time and have some wide stratigraphic range afterwards. Early Scolopodus sometimes also show some shorter costae and not all costae are continuous from the basal part of the element towards the top (like in S. rex Lindström, 1955, which was referred to S. striatus Pander, 1856 by Tolmacheva, 2006). ...
... Tolmacheva (2006) showed that the typical costate elements of Scolopodus are recorded in the upper P. proteus Zone for the first time and have some wide stratigraphic range afterwards. Early Scolopodus sometimes also show some shorter costae and not all costae are continuous from the basal part of the element towards the top (like in S. rex Lindström, 1955, which was referred to S. striatus Pander, 1856 by Tolmacheva, 2006). The fragmented specimens from Morocco resemble S. krummi, which has its FAD in the P. proteus Zone of the Argentine Precordillera (Albanesi, 1998) and is common in the P. elegans Zone (Lehnert, 1995). ...
This study documents conodont faunas of the Fezouata Formation, recovered from the AZ-1 borehole at Adrar Zouggar Mountain and from outcrops near Zagora in south-eastern Morocco. The Fezouata Formation was deposited on the peri-Gondwanan shelf near the South Pole during Early Ordovician times. It is composed of mostly fine-grained siliciclastics and is well known for including beds displaying the exceptionally well preserved Fezouata Biota. Studies on different microfossil groups, including conodonts, increase the diversity recorded from this exceptional ecosystem. Strongly recrystallised conodont elements were extracted from the fine-grained siliciclastic sediments by diluted hydrofluoric acid (HF), which was used for isolating palynomorphs. The material is dominated by simple cone taxa such as Parapaltodus, Semiacontiodus, Scolopodus, Scalpellodus, Drepanoistodus, Acodus, Paltodus, and Cornuodus. In addition, a few elements of early Prioniodus are recovered. This composition allows an estimation of uppermost Tremadocian through basal Floian ages for the fragmented elements because characteristic elements of younger assemblages, including ramiform (e.g., Oepikodus, Baltoniodus) or coniform (e.g., Tropodus, Protopanderodus) apparatuses, have not been recorded. The association is devoid of any warm/tropical and temperate water taxa and is typical for faunas in the cold water environments of the subpolar siliciclastic shelves during Early Ordovician times. The new term of ‘subpolar faunal domain’ is proposed for these conodont associations of low diversity that occur at high southern latitudes during the Early Ordovician. Ecological implications and palaeobiogeographical relationships of the conodont faunas are discussed.
... Remarks. In revising this species, Tolmacheva (2006) proposed a quinquimembrate apparatus, including scandodiform (M), subrounded (Sa), paltodiform (S), compressed paltodiform (S), and acontiodiform (P) elements, and considered both S. quadratus Pander, 1856 and S. rex Lindström, Material. 10 specimens from five samples ( Table 1). ...
Recovery of conodonts and other fossils from four petroleum exploration wells (Esso Tasman 1 and Torres 1; Petrofina Goulburn 1 and Arafura 1), drilled in the Goulburn Graben of the Arafura Basin off the northern coast of Australia, have extended the known distribution of both Ordovician and Cambrian sediments across part of the northern Australian continental margin. The Cambrian and Ordovician sediments in the Arafura Basin comprise the four formations of the Goulburn Group. The recovered fossils indicate that in the offshore, the Jigaimara Formation is most likely of middle to late Templetonian age, the Naningbura Dolomite is Furongian to early Tremadocian, the Milingimbi Formation is middle Tremadocian, and the Mooroongga Formation is of late Tremadocian to middle Floian age.
... 5, fig. 24 Tolmacheva (2006) suggested that S. striatus was the valid name for this multielement species, with the widely-used S. rex forming a junior synonym. Her conclusion is supported by a large collection of Scolopodus collected by one (SB) of the authors from the type locality (Popowka River). ...
... paltodiformis Lindström, 1955a was proposed originally as a form species represented by a short-based, strongly compressed element with multicostate inner lateral face and only faintly costate outer lateral face (Lindström, 1955a, pl. 3, figs 33-34). Tolmacheva (2006, fig. 2) considered them to represent the Sa (subrounded) and M (scandodiform) positions respectively of her revised multielement species, S. striatus. ...
... Our current understanding of Scolopodus is largely based on the now well-established multielement species S. striatus, as the type species originally designated by Pander remains as a poorly known species, whose validity may also be questionable (Tolmacheva, 2006). In the revision by Tolmacheva, S. striatus was defined as having five or more nongeniculate elements representing the M, S and P positions. ...
Forty-four conodont species are documented from the Dawangou section in the Tarim Basin, which spans the Darriwilian to Sandbian interval and is the global auxiliary stratotype for the base of the Upper Ordovician. Five conodont zones are recognized in this section, including the Yangtzeplacognathus crassus, Histiodella holodentata and H. kristinae zones in the upper part of the Dawangou Formation, the Pygodus anserinus Zone from the upper part of the Saergan Formation to the lower part of the Kanling Formation, and the Baltoniodus alobatus Zone in the upper part of the Kanling Formation. Presence of the P. serra Zone is based on occurrences of this species on shale bedding planes in the lower and middle Saergan Formation, but could not be confirmed in acid-leached samples studied from this interval. The Middle/Upper Ordovician boundary occurs within graptolitic black shale of the upper Saergan Formation. Although the boundary interval was intensively sampled, conodonts were very rare, probably due to stagnant or stratified basinal environments. This documentation of the conodont faunas and biostratigraphy of the Dawangou section is considered preliminary and more detailed conodont studies are required, but the remoteness of the site hinders the further extensive sample collection needed for this purpose.
... The study of Ordovician conodonts was initiated by Pander (1856), who in his classical monograph described many Floian (Early Ordovician) species from the St Petersburg region in Russia (Tolmacheva, 2006). However, Late Ordovician representatives of this microfossil group remained virtually unstudied for the next 75 years, the only exception being Hinde's (1879) report of five species (representing 3(?) multi-element species) from the Upper Ordovician Lorraine-Dundas formations of Ontario. ...
The 2003 rediscovery of the long 'lost' Ozora. Missouri classical conodont locality of Branson & Mehl (1933b), from which the worlds first Late Ordovician conodont fauna was described. has made it possible to obtain topotype specimens of the several important conodont species introduced by Branson and Mehl from this site. A taxonomic reassessment of the Ozora conodont fauna indicates that it includes at least 14 multi-clement species, eight of which were previously known front this locality. Several specimens of the taxonomically diagnostic M element of the biostratigraphical key species Amorphognathus ordovicicus were recovered. This element was previously not known from the type locality or the species at Ozora. A general review of the evolution of the genus Amorphognathus shows that some elements. particularly the M and Pa elements, exhibit relatively rapid gradual morphological changes that are helpfull for distinguishing a series of biostratigraphically useful species through the Upper Ordovician (Sandbian-Hirnantian) interval. No ancestor of Amorphognathus has yet been identified but currently available data suggest that the genus appeared in the latest Darriwilian or earliest Sandbian and went extinct in the late Hirnantian. None of the Early Silurian platform genera appears to be closely related to Amorphognathus. J. Micropalaeonatol. 29(1): 73-80. May 2010.
... Lindström (1971, in Ziegler 1974 defined Oistodus as having hyaline multielements, with O. lanceolatus, the type species, consisting of a trimembrate apparatus, including a two-edged element (cordylodiform= M element herein), three-edged asymmetrical element (cladognathodiform= Sb), and threeedged symmetrical element (trichonodelliform= Sa). Tolmacheva (2006) Bergström (1988, pl. 2, figs 17-19). All three specimens representing the M, Sa and Sb elements illustrated by Lindström (in Ziegler 1974, p. 198-199, Oistodus-pl. ...
... Moreover, S. houlianzhaiensis has a distinctive Sc element with a strongly compressed cusp and with lateral costae restricted to the outer lateral face, more commonly near the anterior margin. Scolopodus striatus was revised recently on material, considered to be part of Pander's original type collection from the Lower Ordovician in the vicinity of St. Petersburg, as having a quinquimembrate apparatus (Tolmacheva 2006). Both S. quadratus Pander, 1856, and S. rex Lindstro¨mLindstro¨m, 1955, which are widely cited in the Ordovician conodont literature, were regarded as junior synonyms of S. striatus. ...
Serratognathus diversus An, Cornuodus longibasis (Lindström), Drepanodus arcuatus Pander, and eleven other less common conodonts, including Cornuodus? sp., Oistodus lanceolatus, Protopanderodus gradatus, Protoprioniodus simplicissimus, Juanognathus variabilis, Nasusgnathus dolonus, Paltodus? sp., Scolopodus houlianzhaiensis, Semiacontiodus apterus, Semiacontiodus sp. cf. S. cornuformis and Serratognathoides? sp., are described and illustrated from the Honghuayuan Formation in Guizhou, South China, concluding revision of the conodont fauna from this unit, which comprises 24 species in total. The most distinctive species in the fauna, S. diversus, consists of a trimembrate apparatus, including symmetrical Sa, asymmetrical Sb and strongly asymmetrical Sc elements. This species concept is supported by the absence of any other element types in a large collection represented by nearly 500 specimens of this species. The fauna indicates a late Tremadocian to mid-Floian age (Early Ordovician) for the Honghuayuan Formation, which was widely distributed on the Yangtze Platform in shallow water environments. Previously published biostratigraphic zonations for the Honghuayuan Formation are reviewed, and revised on the basis of our knowledge of the entire conodont fauna, supporting the establishment of three biozones, Triangulodus bifidus, Serratognathus diversus, and Prioniodus honghuayanensis biozones in ascending order. Species of Serratognathus enable correlation between Ordovician successions of South China, North China (North China Platform and Ordos Basin), Tarim Basin, and further afield into Malaysia and northwestern Australia.
