Eubalaena

• Main Author: Boessenecker, Robert W.
• Format: Text
• Language: unknown
• Published: Zenodo 2013
• Subjects: Biodiversity; Taxonomy; Animalia; Chordata; Mammalia; Cetacea; Balaenidae; Eubalaena; baleen whales
• Online Access: https://dx.doi.org/10.5281/zenodo.4818607; https://zenodo.org/record/4818607

cf. Eubalaena sp. 2 REFERRED MATERIAL. — UCMP 219099, a partial left tympanic bulla collected by R.W. Boessenecker from UCMP locality V99846. STRATIGRAPHIC OCCURRENCE. — Uppermost part of the San Gregorio section of the Purisima Formation, Early to Late Pliocene (3.35-2.5 Ma, Piacenzian-Gelasian equivalent; Fig. 2). DESCRIPTION Ŋis larger tympanic bulla is missing most of its outer lip, and is similar in most regards to the above described specimens of cf. Eubalaena sp. 1. It differs from UCMP 219100 in its larger size and several other features; the description of this specimen follows that for cf. Eubalaena sp. 1 except for the differences outlined below. Ŋis specimen further differs from UCMP 219100 by having a much more medially convex involucrum in ventral aspect (Fig. 10D, E). Furthermore, it has a well-defined concave longitudinal furrow laterally adjacent to the main ridge. Ŋe main ridge also forms a welldeveloped ventral keel, and unlike UCMP 219100, the main and involucral ridges are parallel. REMARKS AND COMPARISONS Ŋe great dorsoventral depth and massive medial face of the involucrum identify this specimen as a balaenid (Oishi & Hasegawa 1995b; Ekdale et al. 2011). It differs from Balaena in being transversely thicker, and shares similar large size and transverse thickness with extant Eubalaena , although it is incomplete (Table 5; Ekdale et al. 2011).Ŋe much larger size and younger (Early-Late Pliocene) age of the specimen suggest it is not conspecific with UCMP 219100. Several tympanic bullae of this same size and morphology are known from the Santa Cruz section of the Purisima Formation (UCMP 29852, 167800, SCMNH 9990.07, 21654, 21658; latest Miocene-Early Pliocene, Messinian-Zanclean equivalent, 6.9-4.5 Ma). : Published as part of Boessenecker, Robert W., 2013, A new marine vertebrate assemblage from the Late Neogene Purisima Formation in Central California, part II: Pinnipeds and Cetaceans, pp. 815-940 in Geodiversitas 35 (4) on page 836, DOI: 10.5252/g2013n4a5, http://zenodo.org/record/4538200 : {"references": ["OISHI M. & HASEGAWA Y. 1995 b. - Diversity of Pliocene mysticetes from eastern Japan. hve Island Arc 3: 346 - 452.", "EKDALE E. G., BERTA A. & DEMERE T. A. 2011. - Ne comparative osteology of the petrotympanic complex (ear region) of extant baleen whales (Cetacea: Mysticeti). Plos One 6 (6): 1 - 42."]}