Oswaldella blanconae, ÁLVARO L. PEÑA CANTERO, 2017

ÁLVARO L. PEÑA CANTERO, 2017, Benthic hydroids (Cnidaria, Hydrozoa) from the Ross Sea (Antarctica) collected by the New Zealand Antarctic expedition BioRoss 2004 with RV Tangaroa, Zootaxa 4293 (1), pp. 1-65 : 58-59

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)