Kokenichthys navis, 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 : 10

KOKENICHTHYS NAVIS SCHWARZHANS AND STRINGER , 2020b

FIG. 6A

Material— two eroded, but diagnostic, specimens, specimen figured, DMNH 2021-09-9.

Description and Remarks— The sagitta of Kokenichthys navis has several diagnostic features including its very unusual sulcus, which is located almost entirely dorsally. The shape is mainly oval (sensu Smale et al. 1995) with smooth margins. The ventral margins are fairly sharp, and there is a rostrum. The convex inner face has a broad sulcus that appears very shallow and easily eroded. Other specimens of K. navis show similar erosion (see fig. 6 A in Stringer et al. 2020, on the specimens from the Ripley and Owl Creek formations of Mississippi). However, the other specimens in Stringer et al. (2020, fig. 6C–F) are much better preserved, and the ostial and caudal regions are clearly visible. In addition to the Arkadelphia Formation in Arkansas, K.navis is known from the Ripley Formation in Mississippi and possibly in the Tar Heel Formation in North Carolina (Stringer et al. 2018). The species is very abundant in the Ripley Formation at the Blue Springs locality in northeastern Mississippi with 69 specimens (Stringer et al. 2020).

Figures

Figure 6. Otoliths from the Cretaceous Arkadelphia Formation. All specimens unless otherwise noted are inner views of right sagittae. Length in mm. A. Kokenichthys navis Schwarzhans and Stringer (2020b), DMNH 2021-09-9, 4.10 mm. B. Clupeiform? indeterminate DMNH 2021-09-10, 1.42 mm. C. Arius subtilis Schwarzhans and Bratishko (2011), DMNH 2021-09-11, 4.61 mm. D. Vorhisia vulpes Frizzell (1965b), DMNH 2021-09-13, 2.49 mm. E. Vorhisia vulpes Frizzell (1965b), DMNH 2021-09-14, 3.06 mm. F. Vorhisia vulpes Frizzell (1965b), DMNH 2021-09-15, 3.99 mm. G. Vorhisia vulpes Frizzell (1965b), DMNH 2021-09-16, 7.98 mm. H. Vorhisia vulpes Frizzell (1965b), DMNH 2021-09-12, 19.36 mm.