Apateodus crenellatus, ? SCHWARZHANS AND STRINGER, 2020

Stringer, Gary L. & Sloan, James Carson, 2023, First Cretaceous teleostean otolith assemblage (Arkadelphia Formation, upper Maastrichtian) from Arkansas, USA, early Gadiformes, and the Western Interior Seaway, PaleoBios 40 (1994), pp. 1-39 : 12-14

APATEODUS CRENELLATUS? SCHWARZHANS AND STRINGER ,

2020b

FIG. 7A

Material— three specimens, specimen figured, DMNH 2021-09- 9 .

Description and Remarks— The three Arkadelphia Formation specimens fit the description of Apateodus crenellatus presented in Stringer et al. (2020) from the Ripley Formation in northeastern Mississippi. Unfortunately, none of the thin, fragile specimens have a preserved rostrum like the holotype shown in Stringer et al. (2020, fig. 7 G–I). The outline of A. crenellatus appears to be more oval (sensu Smale et al. 1995), but if the long and moderately pointed rostrum is present, it is more ovate in outline (sensu Smale et al. 1995). The margins are variable, which may be related to erosion. The heterosulcoid sulcus appears to be more slightly ventral and extends across essentially the entire inner fac. The outer face is typically flat and smooth.

The classification of A. crenellatus has been debated for several decades since its initial discovery by Nolf and Dockery (1990) in the Coffee Sand (Campanian) of northeastern Mississippi. Its classification as an aulopiform was first suggested by Stringer et al. (2016) and Stringer et al. (2018). Its classification was confirmed when an otolith was discovered in situ by CT micro-scanning in A. corneti Forir (1887) by Schwarzhans et al. (2018a). This discovery and the subsequent revised taxonomy are also congruent with modern molecular-based phylogenetic and dating studies such as Near et al. (2012), Betancur- R. et al. (2013), Near et al. (2013), and Betancur-R et al. (2017).

Figures

Figure 7. Otoliths from the Cretaceous Arkadelphia Formation. All specimens unless otherwise noted are inner views of right sagittae. Length in mm. A. Apateodus crenellatus? Schwarzhans and Stringer (2020b), DMNH 2021-09-17, 1.78 mm. B. Palaeogadus? belli sp. nov., DMNH 2021-09-18, 1.25 mm (paratype). C. Palaeogadus? belli sp. nov., DMNH 2021-09-19, 1.78 mm (paratype). D. Palaeogadus? belli sp. nov., 2021-09-20, 2.21 mm (paratype). E. Palaeogadus? belli sp. nov., DMNH 2021-09-21, 2.34 mm (paratype). F. Palaeogadus? belli sp. nov., DMNH 2021-09-22, 3.13 mm (holotype). G. Palaeogadus? belli sp. nov., DMNH 2021-09-22, 3.13 mm (holotype, outer view). H Palaeogadus? belli sp. nov., DMNH 2021-09-22, 3.13 mm (holotype, dorsal view).