Oswaldella blanconae El Beshbeeshy 1991

• Main Authors: Peña Cantero, A. L., Vervoort, W.
• Format: Text
• Language: unknown
• Published: Zenodo 2004
• Subjects: Biodiversity; Taxonomy; Animalia; Cnidaria; Hydrozoa; Leptothecata; Kirchenpaueriidae; Oswaldella; Oswaldella blanconae; Antarctic; The Antarctic; Ross Sea; West Antarctica; Victoria Land; South Shetland Islands; Bransfield Strait; Argentino; Blanco; Hallett; Cape Hallett; Antarc*; Antarctica; antartic*; Low Island
• Online Access: https://dx.doi.org/10.5281/zenodo.4654019; https://zenodo.org/record/4654019

Oswaldella blanconae El Beshbeeshy, 1991 (figure 3) Oswaldella blanconae El Beshbeeshy, 1991: 263, 265; Peña Cantero et al ., 1997: 344; Peña Cantero and García Carrascosa, 1998: 179; 1999: 214; Peña Cantero and Vervoort, 1998: 36; Peña Cantero and Marques, 1999: 85. Oswaldella antarctica : Blanco, 1984: 41, pl. 38 figures 86–88. Material examined . 32/1996 , one stem ca 8 mm high (USNM 1003307). Description . 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. Remarks . Oswaldella blanconae is a rare species, hitherto only recorded by Blanco (1984). It is a distinctive species, characterized by hydrotheca placed on basal half or third of the internode, the absence of mesial inferior nematothecae (although a nematophore is present), the shape of the hydrotheca, the presence of one 'mamelon' besides the axillary nematophore on the cauline apophyses, and the arrangement of cauline internodes. Ecology and distribution . Oswaldella blanconae appears to have a circum-Antarctic distribution. The only previous record was from off Low Island, in West Antarctica, at a depth of 90–100 m (Blanco, 1984). Our material comes from east of Cape Hallett (Victoria Land), in the Ross Sea region, where was collected between 344 and 351 m depth. : Published as part of Peña Cantero, A. L. & Vervoort, W., 2004, Species of Oswaldella Stechow, 1919 (Cnidaria: Hydrozoa: Kirchenpaueriidae) from US Antarctic expeditions, with the description of three new species, pp. 805-861 in Journal of Natural History 38 on pages 820-822 : {"references": ["EL BESHBEESHY, M., 1991, Systematische, Morphologische und Zoogeographische Untersuchungen an den Thekaten Hydroiden des Patagonischen Schelfs. PhD thesis, University of Hamburg, Germany, 390 pp., 102 figures, 80 tables.", "PEN \u0360 A CANTERO, A. L. and GARCIA CARRASCOSA, A. M., 1998, Oswaldella vervoorti spec. nov. (Cnidaria: Hydrozoa), a new benthic hydroid from the South Shetland Islands, Antarctica, Zoologische Verhandelingen, 232, 175 - 180.", "PEN \u0360 A CANTERO, A. L. and VERVOORT, W., 1998, On two new species of Oswaldella Stechow, 1919 (Cnidaria, Hydrozoa) from Bransfield Strait (Antarctica), Polar Biology, 20, 33 - 40.", "PEN \u0360 A CANTERO, A. L. and MARQUES, A. C., 1999, Phylogenetic analysis of the Antarctic genus Oswaldella Stechow, 1919 (Hydrozoa, Leptomedusae, Kirchenpaueriidae), Contributions to Zoology, 68, 83 - 93.", "BLANCO, O. M., 1984, Contribucion al conocimiento de hidrozoos antarticos y subantarticos, Contribuciones del Instituto antartico argentino, 294, 1 - 53, pls 1 - 47."]}