Diretmus, (Muller, 1999) (Muller, 1999)

Lin, Chien-Hsiang & Nolf, Dirk, 2022, Middle and late Eocene fish otoliths from the eastern and southern USA, European Journal of Taxonomy 814, pp. 1-122 : 47-48

“ Diretmus ” serratus ( Müller, 1999)

Fig. 15E–H

“genus Caproidarum ” serratus Müller, 1999: 130 , fig. 29/18–21, pl. 16 fig. 8.

“ Diretmida ” serrata – Nolf 2013: 78, pl. 163.

? Diretmus ? cf. D. serratus – Ebersole et al. 2019: 195 , fig. 70a–b.

Remarks

“ Diretmus ” serratus has very short and high otoliths; the dorsal and ventral areas are tapering vertically and extremely extended with pointed tips. On the dorsal rim, the pointed tip is located in the posterior portion; the ventral one is more central. A weakly developed colliculum can be detected, especially in the anterior part of the cauda. The posterior end of the crista superior is slightly bent upward. This combination of features allows us to allocate the species to diretmids, but these features are not found in the recent genus, and thus the fossil species cannot be placed in the extant genus.

Stratigraphic and geographic distribution

Lutetian: Weches Formation and “Stone City beds”, Texas; Dobys Bluff Tongue of Kosciusko Formation, Mississippi; Piney Point Formation, Virginia. Bartonian: Cook Mountain Formation, Texas; “upper” Lisbon Formation, Alabama.

Figures

Fig. 15. Fish otoliths from the US middle and upper Eocene. A–D. Bregmaceros troelli (Dante & Frizzell, 1965). A–B. “Stone City beds”, Alabama Ferry on Trinity River, North, Texas (IRSNB P 10033–10034). C–D. Landrum M., Pin Oak Creek, Texas (IRSNB P 10035–10036). E–H. “Diretmus” serratus (Müller, 1999). E. “Stone City beds”, Stone City Bluff, Brazos River, sample 2 from bed P, Texas (IRSNB P 10037). F. “Stone City beds”, Alabama Ferry, on Trinity River, North, Texas (IRSNB P 10038). G–H. Wheelock M., Little Brazos River, Stenzel loc., Texas (IRSNB P 10039–10040). I–K. “Myripristis” cajun (Frizzell & Lamber, 1961). I. Wheelock M., Little Brazos River, Stenzel loc., Texas (IRSNB P 10041). J–K. “Stone City beds”, Stone City Bluff, Brazos River, Texas (IRSNB P 10042–10043). L–M. Carapus smithvillensis (Dante & Frizzell, 1965), “Stone City beds”, Alabama Ferry, on Trinity River, North, Texas (IRSNB P 10044–10045). 1 = ventral view; 2 = inner view. Scale bars = 1 mm.