Echiophis, KAUP, 1856

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

ECHIOPHIS AFF. E. SEMISPHAEROIDES ( SCHWARZHANS,

2003)

FIG. 5G

Material— 11 specimens, specimen figured, DMNH 2021-09- 07 .

Description and Remarks— These otoliths tend to be primarily circular in shape (sensu Smale et al. 1995). The nearly straight to slightly outwardly curved posterodorsal margin produces a discernible angle. The otolith is thick with mainly smooth margins. The inner face is strongly convex and smooth with a deep sulcus. The sulcus has a long, narrow, and deep cauda, while the ostium is much shorter and shallower. The outer face is flat and relatively smooth. Schwarzhans(2003) originally classified Echiophis semisphaeroides in the family Anguillidae . However, Schwarzhans (2019) illustrated the modern Echiophis brunneus Castro-Aguirre and Suárez de los Cobos (1983), and examination of the specimen has shown a great similarity in convexity and smoothness of the inner face as well as the shape and depth of the sulcus. There are three extant species of Echiophis known from tropical and subtropical America. Modern ophichthid otoliths illustrate significant variability and are still not understood well. In fact, it is often difficult to assign fossil otoliths to genera with very much confidence. However, Schwarzhans and Stringer (2020a) believed that the similarity was significant compared to other known anguilliform otoliths and changed the species to the family Ophichthidae .

Figures

Figure 5. Otoliths from the Cretaceous Arkadelphia Formation. All specimens unless otherwise noted are inner views of right sagittae. Length in mm. A. Elops sp., DMNH 2021-09-01, 1.89 mm. B. Albuliformes indeterminate, DMNH 2021-09-02, 1.42 mm. C. Elopothrissus sp. DMNH 2021-09-03, 1.83 mm. D. Genartina sp. DMNH 2021-09-04, 0.85 mm. E. Osmeroides sp. DMNH 2021-09-05, 3.85 mm. F. Anguilla? chickasawae Schwarzhans and Stringer (2020b), DMNH 2021-09-6, 1.90 mm. G. Echiophis aff. E. semisphaeroides Schwarzhans (2003), DMNH 2021-09-07, 3.25 mm. H. Muraenanguilla? sp. DMNH 2021-09-08, 2.18 mm.