Protopanderodus nogamii ( Lee, 1975 )

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 : 207-209

publication ID	https://doi.org/ 10.3853/j.0067-1975.55.2003.1383
persistent identifier	https://treatment.plazi.org/id/37439A20-CB0D-FF15-FC66-FF50FC6BFB6E
treatment provided by	Felipe
scientific name	Protopanderodus nogamii ( Lee, 1975 )
status

Treatment

Protopanderodus nogamii ( Lee, 1975)

Fig. 23A–P View Fig ,?Q

Scolopodus cf. bassleri Igo & Koike, 1967: 23, pl. 3, figs. 7, 8, text-fig. 6B.

Scolopodus sp. A Hill et al., 1969: O.14, pl. O VII, fig. 13.

Scolopodus sp. C Hill et al., 1969: O.14, pl. O VII, fig. 15. Panderodus sp. Serpagli, 1974: 59 , pl. 24, figs. 12, 13, pl. 30, figs. 12, 13.

Scolopodus nogamii Lee, 1975: 179 , pl. 2, fig. 13.

Protopanderodus primitus Druce (MS) , in Cooper, 1981 (nomen nudum): 174, pl. 27, figs. 3, 4 (cum syn.).

Scolopodus euspinus Jiang & Zhang , in An et al., 1983: 140, pl. 13, fig. 27, pl. 14, figs. 1–8 (cum syn.).

Protopanderodus nogamii .– Watson, 1988: 124, pl. 3, figs. 1, 6.

Scolopodus euspinus .–An & Zheng, 1990: 173, pl. 2, figs. 7–11, 13, 14, 16.

Protopanderodus primitus .–Stait & Druce, 1993: 307, figs. 13A– C, 18D,E,G–K (cum syn.).

Parapanderodus paracornuformis .–Albanesi, in Albanesi et al., 1998: 116, partim pl. 12, fig. 13, 8?–10?, non 11, 12.

Material. Three specimens (2 Sb, 1 Sc) from the Tabita Formation at Mount Arrowsmith, and 128 specimens (12 Pa, 18 Pb, 35 Sa, 55 Sb, 5 Sc, 3 Sd) from unnamed dolomitic limestone unit at Koonenberry Gap .

Description. A species of Protopanderodus consisting of a seximembrate apparatus; all elements with a distinctive deep and narrow furrow on one lateral side (Sc) or both sides (other elements); surface coarsely striated, with striae more prominent on the base. P elements slightly asymmetrical, more laterally compressed, with a median furrow on each side and a shorter base; cusp with a broad anterior face, and a sharp blade-like posterior margin; basal cavity peanutlike in outline ( Fig. 23I,N View Fig ); some specimens ( Fig. 23J View Fig ) with a prominent rounded costa situated posterior to the furrow on the inner lateral face. The Pa element ( Fig. 23I–N View Fig ) has a suberect cusp and shorter base, the curvature between the posterior margin of the cusp and the base is about 90° or slightly less; the Pb element ( Fig. 23 O,P View Fig ) has a more or less proclined cusp with a longer base, and a more gradational curvature between the posterior margin of the cusp and the base. S elements are less laterally compressed, with a longer base, and a more or less rounded posterior margin. Sa element ( Fig. 23A,B View Fig ) symmetrical with a furrow on each side; Sb element similar to Sa, but with a more laterally compressed base ( Fig. 23C,D View Fig ); Sc element ( Fig. 23E,F View Fig ) asymmetrical, with a furrow only on inner lateral face; Sd element similar to Sb but asymmetrical, with cusp slightly twisted and curved inward ( Fig. 23G,H View Fig ).

Remarks. This species is characterized by having a distinctive deep furrow on one or two lateral faces, and by its coarsely striate surface. The furrow is not a true panderodontid furrow, and disappears just before reaching the basal margin, as do also the coarse striae.

[continuation of Fig. 22 View Fig caption]… M/A11-3, outer lateral view; N, Sb element, AMF 120445, M/A11-3, inner lateral view; O–Q, Sc element, AMF 120446, Y4–2, O, outer lateral view, P, inner lateral view, Q, inner lateral view, close up showing the fine striae; R, Sc element, AMF 120447, Y4–3, inner lateral view. Scale bars 100 µm, unless otherwise indicated.

Although Cooper (1981) figured two S elements of Protopanderodus primitus Druce (MS) , he provided neither adequate description nor designation of the types in the expectation that the species would be fully described by Druce in a subsequent publication. However, the species was not formally introduced until Stait & Druce (1993) designated the specimen figured by Cooper (1981, pl. 27, fig. 4) as the lectotype and the other figured specimen ( Cooper, 1981, pl. 27, fig. 3) as the paralectotype for P. primitus . They also cited Cooper as the original author of the species, rather than Druce. Jiang & Zhang (in An et al., 1983) in the meantime had erected Scolopodus euspinus , based on material from the Beianzhuang Formation (approximately Chewtonian to Castlemainian age) of Hebei Province, North China, without knowledge of Cooper’s work. Jiang & Zhang (in An et al., 1983) described S. euspinus as a form species characterized by a furrow on each side and a low costa immediately anterior to it. Among their figured specimens, two morphotypes can be recognized—one, represented by the holotype ( An et al., 1983, pl. 14, fig.3) and two other illustrated specimens (pl. 14, figs. 1, 2), is more laterally compressed with a wider base (referred to herein as the P elements ), while the other morphotype (assigned here to the S elements ) is less laterally compressed with a longer base (see An et al., 1983, pl. 14, figs. 4, 5).

Stait & Druce (1993) correctly considered S. euspinus conspecific with P. primitus , but the Chinese species has priority over P. primitus which in 1983 was a nomen nudum. They revised this species in terms of multielement terminology, referring the laterally compressed symmetrical form to the Pa element , and also recognized an asymmetrical Pb element. The less laterally compressed symmetrical form was assigned to the Sa element . Two additional asymmetrical elements, one uni-furrowed (here referred to Sc) and a tri-furrowed form were also recovered from the Coolibah Formation to form the first symmetry transition series (Stait & Druce, 1993). The Sc element is comparatively rare in the western New South Wales faunas. The Sb element defined by Stait & Druce (1993) is similar to the Sa, but slightly asymmetrical with the furrow on the outer lateral face situated more towards the posterior margin and with the cusp slightly curved inward—it is recognized here as the Sd element . Their figured tri-furrowed Sd element (Stait & Druce, 1993, fig. 18K) is regarded as representing the Pb position, being laterally compressed with a proclined cusp and a shorter base. The rounded second costa posterior to the furrow on the inner side is not considered a distinctive feature. It may occur in either Pa ( Fig. 23J View Fig herein) or Pb (Stait & Druce, 1993, fig. 18K) elements, and in our material is relatively weak in comparison with the specimen illustrated by Stait & Druce (1993).

Watson (1988) interpreted Protopanderodus euspinus as a junior synonym of Protopanderodus nogamii ( Lee, 1975) . Jiang & Zhang (in An et al., 1983) differentiated P. nogamii from P. euspinus mainly on its shorter base and reclined cusp. They stated that whereas both species generally cooccur over an extended stratigraphic range in North China, from the Liangjiashan Formation (Bendigonian) to the Fengfeng Formation (Gisbornian) of North China, only P. nogamii was recorded from South China ( An, 1987), and therefore, the species were treated as separate.

Protopanderodus nogamii was originally described from the Nandal Formation, of suggested Middle Ordovician age, in North Korea. Based on the illustration of the holotype and only figured specimen ( Lee, 1975, pl. 2, fig. 13), the following differences in comparison with the type material of P. euspinus are noticed. The holotype of P. nogamii is a larger specimen (width of the base 570 µm), with a reclined cusp, and coarser striae (8/100 µm) which are developed only on a shorter, posteriorly more extended base. In contrast, the holotype of P. euspinus is smaller (width of the base 150 µm) with a proclined or suberect cusp, and bears finer striae (20–25/100 µm). Otherwise, the two species are closely comparable, with P. nogamii representing one extreme morphotype in the species apparatus (Albanesi pers. comm., 2002). Therefore, despite being defined on a solitary element, P. nogamii —according to strict application of nomenclatural priority—takes precedence over P. euspinus and all other synonyms mentioned in this discussion.

An & Zheng (1990: 173) included two specimens designated as? Panderodus sp. by Ethington & Clark (1982) from the Lehman Formation of the Ibex area, Utah, with Protopanderodus euspinus . Since both specimens appear to have a true panderodontid furrow situated on the posterior face, it seems that this reassignment is unjustified.

One specimen ( Fig. 23Q View Fig ) from Koonenberry Gap (C1612) is a symmetrical element resembling P. nogamii , but is doubtfully assigned due to its much shorter proclined cusp, and a curved lateral costa and furrow on each side. These variations might reflect some kind of pathological deformation.

Kingdom	Animalia
Phylum	Chordata
Class	Conodonta
Order	Conodontophorida
Family	Protopanderodontidae
Genus	Protopanderodus