Galeocerdo, MULLER AND HENLE, 1837
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publication ID |
https://doi.org/ 10.5070/P939056976 |
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publication LSID |
lsid:zoobank.org:pub:13E6A6E9-DE0F-4C71-BE40-2957F48D9F70 |
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persistent identifier |
https://treatment.plazi.org/id/03DF0849-4136-FFDC-3EBD-F895FC1AFC80 |
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treatment provided by |
Felipe |
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scientific name |
Galeocerdo |
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GALEOCERDO MÜLLER AND HENLE, 1837 View in CoL GALEOCERDO ADUNCUS AGASSIZ, 1835
FIG. 5F View Figure 5
Type species — Squalus cuvier Péron and Lesueur,
1822 in Lesueur 1822; Recent.
2001 Physogaleus aduncus ( Agassiz, 1835) ; Ward and Bonavia, page 138.
2009a Physogaleus aduncus ( Agassiz 1843) ; Cicimurri and Knight, p. 632–633, fig 5E.
Referred specimens (n=3) —SC2007.36.17 ( Fig. 5F View Figure 5 ), SC2007.36.18 (two teeth).
Remarks —This tooth morphology was reported by Cicimurri and Knight (2009a) from the Chandler Bridge Formation, but they followed the work of Ward and Bonavia (2001) and referred the material to Physogaleus contortus . The possible conspecific association of the aduncus and contortus morphologies has long been considered ( Applegate 1978, Gottfried 1993, Manning 2006) due to their regular co-occurrence in Neogene strata. Purdy et al. (2001) maintained the two morphologies as distinct species and considered the variation to reflect a difference in feeding preferences between two taxa. Ward and Bonavia (2001), however, considered the two morphologies as conspecific and went on to associate the material with Physogaleus (i.e., P. aduncus ), a taxon known to exhibit strong dignathic and gynandric heterodonty ( Cappetta 2012). Reinecke et al. (2001) later associated the two morphologies as Galeocerdo aduncus . However, in the German Oligocene the two morphologies have since been considered as separate species, G. aduncus and P. contortus , because they are apparently rarely, if ever, coeval ( Reinecke et al. 2005, Reinecke and Hoedemakers 2006). More recently, Türtscher et al. (2021) provided morphometric data supporting both G. aduncus and P. contortus as separate and valid species.
Galeocerdo aduncus exhibits a uniformly convex mesial cutting edge bearing coarse compound serrations that extend nearly to the cusp apex, the distal cutting edge is more finely serrated nearly to the cusp apex, and the denticles on the distal heel are larger and serrated on their mesial and distal edges. These features are consistent with teeth of Recent G. cuvier ( Lesueur, 1822) that we examined (i.e., SC2001.120.10), and contrasts with most species of Physogaleus (excluding P. contortus ), on which much, if not all, the mesial edge is smooth, the mesial serrae that do occur are not compound, the distal cutting edge is smooth, and the distal heel cusplets are not serrated.
A brief discussion on the higher-level taxonomic assignment of Galeocerdo is warranted. Poey (1875) assigned Galeocerdo to the family Galeorhinidi and subfamily Galeocerdini (p. 86). In current usage, the name Galeocerdini implies Tribe ranking, and more recent taxonomic listings have placed Galeocerdo within the subfamily Galeocerdinae Whitley, 1934 (i.e., Cappetta 2012, Reinecke et al. 2014). However, if Galeocerdo is excluded from the family Carcharhinidae (to which it has classically been assigned), this subfamily attribution is unnecessary. Herman et al. (2010) advocated for the placement of Recent and fossil species of Galeocerdo within their Galeocerdidae , which has been followed by other authors with regard to fossil species (i.e. Ebersole et al. 2019). Most recently, Ebert et al. (2021) utilized Galeocerdidae , which is followed herein. Although Ebert et al. (2021) attributed authorship to Poey (1875), Poey’s original spelling is inconsistent with that of Herman et al. (2010), and we follow the latter in this respect. Additional discussion on this topic can be found in Ebersole et al. (2019).
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