Late Maastrichtian Radiolaria from ODP Leg 165 - Site 999 B, Colombian Basin Author Kochhann, Karlos G. D. Author Baecker-Fauth, Simone Author Fauth, Gerson text Geodiversitas 2013 2013-03-29 35 1 5 20 http://dx.doi.org/10.5252/g2013n1a1 journal article 6418 10.5252/g2013n1a1 601d4544-4775-454a-a797-677f0212775b 1638-9395 4538016 Dictyomitra sp. 2 ( Fig. 4F ) FIGURED SPECIMEN. — ULVG-7324. MATERIAL. — 23 specimens (recovered with the hydrogen peroxide method); two specimens (recovered with the acetic acid method). DESCRIPTION Multi-segmented form (six to eleven segments), with test elongated and conical shape. Well-developed and vertically aligned costae obscured on cephalis. Cephalis slightly acute apically. Between adjacent costae, a single parallel row of aligned sub-circular pores or sub-circular depressions is present. Deep and well-developed constrictions occur at joints between segments, formed possibly by one or two transverse pore rows, and are followed by the costae outline. Costae are normally obscured at strictures. One transverse depressed row is present on the central part of each abdominal and post-abdominal segment. Lateral outline of the test strongly lobulated at segmental division levels. Chambers gradually increasing in length and width distally. Distal margin ragged, having, or not, small costal projections. REMARKS Dictyomitra sp. 2 differs from both D. multicostata Zittel, 1876 and D. formosa Squinabol, 1904 by the transverse depression in the central part of each abdominal and post-abdominal segment. Likewise, D. formosa normally presents the first postabdominal segment inflated, producing a kind of ledge neck, and does not have constrictions at the apical (proximal) region. Dictyomitra multicostata has slighter constrictions. This species presents some similarities to Dictyomitra sp. 2, recorded by Aumond et al. (2009) from Maastrichtian strata of ODP Hole 1001B, but it has segments more angular in outline.