Oswaldella blanconae CANTERO, 2017, sp. nov.

Oswaldella blanconae sp. nov. (*)

Oswaldella blanconae El Beshbeeshy, 1991: 263, 265; Peña Cantero et al., 1997b: 344; Peña Cantero & García Carrascosa, 1998: 179; 1999: 214; Peña Cantero & Vervoort, 1998: 35, 36; 2004: 820–822, fig. 3; Peña Cantero & Marques, 1999: 85; González Molinero & Peña Cantero, 2015: 433; Miranda et al., 2016: 598 (nomen nudum)

Oswaldella antarctica — Blanco, 1984: 41, pl. 38 figs 86–88.

Remarks. According to Miranda et al. (2016), the binomen Oswaldella blanconae, proposed by El Beshbeeshy (1991), and later used for several authors, is a nomem nudum. I am here making it available by designating the 8 mm high stem described by Peña Cantero & Vervoort (2004) as holotype (National Museum of Natural History, Smithsonian Institution, Washington, DC, USA, USNM 1003307).

Description (from Peña Cantero & Vervoort 2004: 820-822). “Stem monosiphonic, unbranched (figure 3A), provided with apophyses alternately arranged in two longitudinal rows. Stem divided into internodes each with one apophysis, internodes arranged in zigzag fashion; stem internodes with bifurcation at origin of cauline apophysis. Angle between long axis of cauline internode and apophyses wider than 45°; angle between cauline apophyses and succeeding cauline internode ca 90° (figure 3A). Cauline apophyses provided with two nematophores: one emerging through a hole in perisarc of axil (figure 3B) and another nematophore emerging through a ‘mamelon’ situated laterally on dorsal side of apophysis (figure 3C). Distinct node present between cauline apophyses and hydrocladia (figure 3C). Hydrocladia undivided or bifurcated (figure 3A); up to secondary hydrocladia present; arrangement always symmetrical. Hydrocladia homomerous; all internodes hydrothecate; distal internodes apically truncated.

Hydrocladial internodes provided with one hydrotheca and two nematophores (figure 3B, D–G): one mesial superior emerging through a perisarc hole situated behind free portion of adcauline hydrothecal wall and one mesial inferior, deprived of nematotheca, emerging through a perisarc hole situated on a strongly marked elevation of internode (angle between long axis of hydrocladial internode and steep slope of infrathecal elevation almost 90°).

Hydrothecae placed on basal half or basal third of hydrocladial internodes (figure 3), shallow; aperture circular and either perpendicular to longitudinal axis of internode or slightly tilted downwards; rim even. Adcauline wall of hydrotheca with conspicuous free portion, abcauline wall straight, running smoothly into wall of internode; angle with long axis of internode ca 45°.

Gonothecae absent.”

Distribution. Circum-Antarctic (Peña Cantero & Vervoort 2004). In the Ross Sea, known off Cape Hallett (Peña Cantero & Vervoort 2004)