Remingtonocetidae, Kumar and Sahni, 1986

Uhen, Mark D. & Peredo, Carlos Mauricio, 2021, The first possible remingtonocetid stem whale from North America, Acta Palaeontologica Polonica 66 (1), pp. 77-83 : 79

? Remingtonocetidae indet.

Fig. 2 .

Material.— USNM 449550 , partial premolar ( Fig. 2B ) from middle Eocene , Martin Marietta Quarry (formerly Superior Stone Quarry), near Castle Hayne, North Carolina, USA (34°21’30” N, 77°52’ W, Paleobiology Database collection 5459) .

Description.— USNM 449550 includes portion of a tooth, including the main central cusp, and the posterior portion of the crown ( Fig. 2B ). The posterior root is also present, and extends farther posterior than the posterior edge of the crown. The enamel of the crown displays vertical rugosities. There are small cingula on the medial, lateral, and posterior edges. There is also a small secondary cusp on the posterior heel of the tooth. The central cusp displays light apical wear, and the posterior cusp displays heavy apical wear to the point of being almost worn away. No lateral wear is evident on the tooth. The tooth is also very narrow mediolaterally, and long anteroposteriorly. The crown is 9.3 mm wide directly below the central cusp. The anteroposterior distance from the central cusp to the posterior margin, measured parallel to the cingulum is 27.5 mm.

Remarks.—Precise information on the horizon where the tooth was collected is lacking. However, Kier (1980) states that the rocks in the quarry are from the Castle Hayne Formation, and that they are Bartonian (late middle Eocene) in age. There is considerable debate in the literature about the age and age range of the Castle Hayne Formation. Some authors consider the Castle Hayne Formation to span from the middle to late Eocene ( Harris and Laws 1997). Others restrict the Castle Hayne to the middle Eocene ( Coffey and Read 2004) or even some smaller portion of the middle Eocene ( Weems et al. 2004). This debate is in part due to different opinions on what is part of the Castle Hayne Formation versus an overlying formation, but is also due to differing opinions on the ages of the rocks themselves. Nevertheless, all parties agree that the rocks in the Superior Stone Quarry are of middle Eocene age, most likely from the Lutetian or early Bartonian.

Figures

Fig. 2. A. Remingtonocetus sp. (IITR-SB 2630) from Lutetian; Kachchh, India; right P4. B.?Remingtonocetidae indet. (USNM 449550) from Lutetian– Bartonian; Martin Marietta Quarry (formerly Superior Stone Quarry), near Castle Hayne, North Carolina, USA. Shown as if it were an upper premolar for comparison, but it may also represent a lower premolar as well. Note the extreme narrowness of the tooth. In lateral (A2, B2), medial (A1, B1), and occlusal (A3, B3) views.