A new fossil rorqual (Mammalia, Cetacea, Balaenopteridae) from the Early Pliocene of the North Sea, with a review of the rorqual species described by Owen and Van Beneden Author Bosselaers, Mark Author Post, Klaas text Geodiversitas 2010 2010-06-30 32 2 331 363 http://www.bioone.org/doi/abs/10.5252/g2010n2a6 journal article 10.5252/g2010n2a6 1638-9395 5382040 Genus Diunatans n. gen. TYPE SPECIES . — Diunatans luctoretemergo n. sp. ETYMOLOGY. — Diunatans : “diu” = long time (and hence long distance-) and “natans” (> natare) = swimming (swimmer). DIAGNOSIS. — Diunatans n. gen. is a small sized rorqual, roughly of the size of extant B. acutorostrata Lacépède, 1804 , characterised by: very short nasal; mediolaterally wide pterygoid fossa; large, robust and prominent occipital condyle; mediolaterally wide squamosal body lateral to the supraoccipital; dorsal bulge on squamosal; tympanic bulla very large compared to zygomatic width; wide, globose tympanic bulla (L/W ratio: 1.24) with sigmoid process perpendicular to long axis; rounded and bulbous pars cochlearis (L/W ratio: 1.23-1.26); very long, slender and curved stapes; massive and square basioccipital process; wide basioccipital.