Protopanderodus gradatus Serpagli, 1974

Zhen, Yong Yi, Percival, Ian G. & Webby, Barry D., 2003, Early Ordovician Conodonts from Far Western New South Wales, Australia, Records of the Australian Museum 55 (2), pp. 169-220 : 204-207

publication ID	https://doi.org/10.3853/j.0067-1975.55.2003.1383
persistent identifier	https://treatment.plazi.org/id/37439A20-CB08-FF1B-FCA5-F982FD2FFD01
treatment provided by	Felipe (2021-08-21 20:31:20, last updated 2023-11-09 19:44:58)
scientific name	Protopanderodus gradatus Serpagli, 1974
status

Treatment

Fig. 22A–K View Fig

Protopanderodus gradatus Serpagli, 1974: 75 , pl. 15, figs. 5a– 8b, pl. 26, figs. 11–15, pl. 30, fig. 1a,b; text-fig. 17.

Protopanderodus gradatus .–Zhen et al., in press: pl. 5, figs. 1–10 (cum syn.).

Material. Ten specimens (4 Sb, 4 Sc, 2 Sd) from limestone nodules within shales of the upper Yandaminta Quartzite, and 69 specimens (11 Sa, 16 Sb, 17 Sc, 25 Sd) from the overlying Tabita Formation at Mount Arrowsmith ; 31 specimens (1 Sa, 7 Sb, 12 Sc, 11 Sd) from unnamed dolomitic limestone unit at Koonenberry Gap .

Remarks. This species was recently reported from the slightly older (upper P. elegans Zone ) Hensleigh Siltstone of central New South Wales, where five morphotypes were recognized (Zhen et al., in press). Four elements have been recovered from the western New South Wales samples, and are regarded as occupying S positions in the species apparatus. The Sa element (termed element “d” by Zhen et al., in press) is symmetrical or nearly so with a posterolateral costa and an anterolateral costa on each side ( Fig. 22A,H– J View Fig ). The Sb element (element “c” of Zhen et al., in press) is weakly asymmetrical, with a lateral costa on each side and slightly inner laterally curved cusp ( Fig. 22C,D View Fig ). Specimens referred to as element “b” by Zhen et al. (in press) may represent a variant of the Sb element ; they are not recognized here. The Sc element is strongly asymmetrical with a smooth outer face and a costate inner face ( Fig. 22E,F View Fig ). It is similar to element “a” from the Hensleigh Siltstone, but the latter is more strongly twisted with a smooth inner face and a costate outer face. The Sd element (element “e” of Zhen et al., in press) is similar to the Sa with a posterolateral costa and an additional anterolateral costa on each side, but apparently asymmetrical ( Fig. 22B,G,K View Fig ).

Our specimens are identical with the type material from the San Juan Formation of Argentina ( Serpagli, 1974). In lateral view, elements of P. gradatus from the Hensleigh Siltstone are less laterally compressed with the basal margins more or less straight, rather than gently curved as shown by the types from the Argentine Precordillera .

References

Cooper, B. J., 1981. Early Ordovician conodonts from the Horn Valley Siltstone, central Australia. Palaeontology 24: 147 - 183.

Serpagli, E., 1974. Lower Ordovician conodonts from Precordilleran Argentina (Province of San Juan). Bollettino della Societa Paleontologica Italiana 13: 17 - 98.

Figures

Fig. 22. A–K, Protopanderodus gradatus Serpagli, 1974: A, Sa element, AMF120436, M/A11-1, posterolateral view; B, Sd element, AMF120437, C1612, outer lateral view; C,D, Sb element, AMF120438, C1612, C, inner lateral view, D, outer lateral view; E,F, Sc element,AMF120439, C1612, E, inner lateral view, F, outer lateral view; G, Sd element, AMF120440, C1612, outer lateral view; H–J, Sa element,AMF120441,Y4–2, H,I, lateral views, J, close up showing the fine striae; K, Sd element,AMF120442, C1612, inner lateral view. L–R, Protopanderodus leonardii Serpagli, 1974: L, Sa element,AMF120443, M/A11-3, lateral view; M, Sb element,AMF120444,