Scolopodus Pander, 1856
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publication ID |
https://doi.org/ 10.3853/j.0067-1975.63.2011.1586 |
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persistent identifier |
https://treatment.plazi.org/id/03CCEB77-FFE1-6343-FE58-FAFC9191FACD |
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treatment provided by |
Felipe |
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scientific name |
Scolopodus Pander, 1856 |
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Type species. Scolopodus sublaevis Pander, 1856 .
Remarks. Scolopodus is well-defined and widely understood as a dominantly hyaline, robust, thick-walled coniform genus with a non-expanded base and sharp costae. However, as Pander’s (1856) original material was lost, there has long been confusion and misinterpretations concerning various species erected by Pander (1856) and several subsequent authors (e.g., Lindström, 1955a). Pander (1856) recognized six form species of Scolopodus , including S. sublaevis , S. striatus , S. costatus , S. semicostatus , S. aequilateralis , and S. quadratus . Fåhraeus (1982a) considered that only two species were valid, namely the type species, S. sublaevis (= S. aequilateralis ), and S. quadratus (= S. costatus and S. striatus ); furthermore he regarded S. rex Lindström, 1955a as a junior synonym of S. quadratus . Based on material recovered from the Mining Institute in St. Petersburg that is believed to be part of Pander’s type collection, and additional new material collected from one of Pander’s original localities on the Popowka River of St. Petersburg, Tolmacheva (2006) provided a comprehensive revision of Pander’s species of Scolopodus . She concluded that all Pander’s form species belonged to a single species, except for the type species, S. sublaevis , which was not recognized in her material. 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).
Scolopodus rex Lindström, 1955a was erected as a form species of a multicostate symmetrical element with rounded cross section ( Lindström, 1955a, pl. 3, fig. 32), and S. rex var. 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. However, some species of Scolopodus , such as S.? oistodiformis An & Ding, 1985 from China, and S. subrex Ji & Barnes, 1994 and S. cornutiformis (Branson and Mehl, 1933) from North America, have a distinctive geniculate M element in their species apparatus, rather a nongeniculate scandodiform M element as in S. striatus . S.? oistodiformis is widely reported in the Darriwilian of South China and Tarim. Its M element from the Dawangou Formation ( Fig. 27A–C View Figure 27 ) is geniculate with a recurved, robust and antero-laterally strongly compressed cusp, which has a smooth, non-costate anterior face and a costate less convex posterior face. It remains uncertain whether this distinctive species group with a geniculate M element should be included in Scolopodus .
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