Early Eocene fish otoliths from the eastern and southern USA Author Lin, Chien-Hsiang 50EBAA8C-3EE0-4655-A0BB-694D9A8F49BA Biodiversity Research Center, Academia Sinica, 128 Academia Road, Seca 2, Nankang, Taipei 11529, Taiwan. chlin.otolith@gmail.com Author Steurbaut, Etienne 9A884B23-5D05-4D6C-92B8-08B321D16845 Royal Belgian Institute of Natural Sciences, 29 Vautier Street, 1000 Brussels, Belgium. & Department of Earth and Environmental Sciences, KU Leuven, Celestijnenlaan 200 E, 3001 Leuven, Belgium. etienne.steurbaut@naturalsciences.be Author Nolf, Dirk 6BCC71A0-1BEE-4BC0-BDFC-D070609DEFAB Royal Belgian Institute of Natural Sciences, 29 Vautier Street, 1000 Brussels, Belgium. dirk.nolf@scarlet.be text European Journal of Taxonomy 2024 2024-06-04 935 203 240 https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2557/11559 journal article 10.5852/ejt.2024.935.2557 2118-9773 11526096 6C66A1E4-7EA4-45B7-B261-5D3ED749568E “ Haemulon ” ypresiensis sp. nov. urn:lsid:zoobank.org:act: AA387688-D529-4AF7-B3DA-C6E3C2A82413 Fig. 10G–H Diagnosis OL/OH = 1.3–1.5, OsL/CaL = 0.4–0.7. Oblong otoliths with weak postero-dorsal angle. Margins crenulated. Sulcus well-divided. Ostium wide, opens antero-dorsally. Cauda elongate, straight, but strongly bent ventrally at posterior. Etymology ‘ Ypresiensis , is , e ’ = ‘from the Ypresian’. Refers to the geological stage from where the fossils were collected. Type material examined Holotype UNITED STATES OF AMERICA • Left otolith ; Virginia , Pamunkey River , Hanovertown , Potapaco Member ; Fig. 10G ; IRSNB P 10766 . Paratypes ( 72 in total) UNITED STATES OF AMERICA • 2 otoliths of which one is figured: Fig. 10H ; same collection data as for holotype; IRSNB P 10767 • 10 otoliths ; Mississippi , Meridian , Gallagher Creek , Bashi Formation ; IRSNB • 36 otoliths ; Mississippi , Meridian , Red Hot Truck Stop, Bashi Formation ; IRSNB • 13 otoliths ; Alabama , Cave Branch , Bashi Formation ; IRSNB • 1 otolith ; Alabama , Elba Dam on Pea River , Bashi Formation ; IRSNB • 4 otoliths ; Alabama , Ozark , Bashi Formation ; IRSNB • 2 otoliths ; Alabama , Hatchetigbee Bluff , Hatchetigbee Formation ; IRSNB • 3 otoliths ; Virginia , Rappahannock River , Potapaco Member; IRSNB • 1 otolith ; Maryland , Loyola Retreat House , N of Popes Creek , Woodstock Member; IRSNB . Type locality and horizon United States of America , Pamunkey River, Hanovertown ( Virginia ), Potapaco Member. Dimensions of the holotype Length = 3.33 mm ; height = 2.19 mm ; thickness = 0.76 mm . Description This species is distinguished by oblong otoliths with crenulated margins and a moderately thick build. The inner face is convex and the outer face is concave. The sulcus is clearly devided with crest-like cristae forming a deep incised sulcus. The ostium opens widely and antero-dorsally, and an expansion is present at the ostial lobe. The junction of the ostial and caudal crista inferior is located more posteriorly with respect to the same junction in the crista superior. The cauda is straight for about two-thirds of its length and markedly bent ventrally at the posterior end. The dorsal area is narrower than the ventral one. There is a shallow dorsal depression located just above the crest-like caudal crista superior. Fig. 10. Fish otoliths from the US lower Eocene formations. A . Lactarius amplus Stinton, 1978 , Taylor’s Branch of Two Mile Creek, Reklaw Fm., Texas (IRSNB P 10757). B–C . Lactarius kokeni (Dante & Frizzell, 1965) , Taylor’s Branch of Two Mile Creek, Reklaw Fm., Texas (IRSNB P 10758, P 10759). D . Anisotremus rambo , 2022, Taylor’s Branch of Two Mile Creek, Reklaw Fm., Texas (IRSNB P 10763). E–F . Orthopristis burlesonis (Dante & Frizzell, 1965) , Pamunkey River, Hanovertown, Potapaco Member, Virginia (IRSNB P 10764–10765). G–H . “ Haemulon ” ypresiensis sp. nov., Pamunkey River, Hanovertown, Potapaco Member, Virginia. G . Holotype (IRSNB P 10766). H . Paratype (IRSNB P 10767). I–J . Ekokenia eporrecta ( Koken, 1888 ) , Taylor’s Branch of Two Mile Creek, Reklaw Fm., Texas (IRSNB P 10768, P 10769). 1 = ventral view; 2 = inner view. Scale bars = 1 mm. Remarks The otoliths of “ H. ” ypresiensis sp. nov. are most similar to those of “ Haemulon ” pulchrum (Frost, 1934) and “ Haemulon ” obliquum ( Müller, 1999 ), based on their sulcus and outline shape. “ Haemulon ” pulchrum is a widely distributed Eocene European species, and the otoliths of the new species resemble those from the Lutetian of Osteroden, Germany (see Schwarzhans 2007 : fig. 32; Lin et al . 2017b : fig. 12h–l). However, the dorsal rim of the new species is flat, whereas in “ H. ” pulchrum , it is notably elevated and forms the highest part of the otoliths. On the other hand, “ H. ” obliquum , a middle to late Eocene American species (see Lin & Nolf 2022 ), has otoliths that are more similar to the new species, with the largest difference being that the cauda tip extends further backwards and is more markedly bent, reaching almost to the posterior rim of the otoliths. Stratigraphic and geographic distribution Ypresian: Bashi Formation, Mississippi and Alabama ; Hatchetigbee Formation, Alabama ; Potapaco Member, Virginia and Maryland . Remarks on taxa requiring comments