Oswaldella rigida Peña Cantero, Svoboda & Vervoort, 1997

Molinero, A. González & Peña Cantero, A. L., 2015, SEM study of species of Oswaldella Stechow, 1919 (Cnidaria, Hydrozoa, Kirchenpaueriidae), with an annotated checklist of the species of the genus, Zootaxa 4052 (4), pp. 401-441 : 416-419

publication ID

https://doi.org/ 10.11646/zootaxa.4052.4.1

publication LSID

lsid:zoobank.org:pub:47EF6E9D-9064-4899-B3DD-276FF7C969EB

DOI

https://doi.org/10.5281/zenodo.6107471

persistent identifier

https://treatment.plazi.org/id/03C287C6-2804-7C04-D4F4-8F932D2E7944

treatment provided by

Plazi

scientific name

Oswaldella rigida Peña Cantero, Svoboda & Vervoort, 1997
status

 

Oswaldella rigida Peña Cantero, Svoboda & Vervoort, 1997 View in CoL

( Figs 11 View FIGURE 11 , 16 View FIGURE 16 K, 18C, 20C)

Material examined. New Zealand Antarctic Expedition TAN0402: Stn 88, Tangaroa , 14 February 2004, 72°05'86''S, 172°55'81''E (Cape Adare, Ross Sea), 515 m.

Description. Monosiphonic, usually unbranched stems, up to 210 mm high, usually divided into internodes. Angle between cauline apophyses and stem 70–90°. Perisarc strongly developed. Cauline apophyses with two axillary nematophores, each emerging through simple perisarc holes ( Fig. 11 View FIGURE 11 B–C).

Hydrocladia typically bifurcated ( Fig. 11 View FIGURE 11 A), but up to third-order branching present. First hydrocladial internode bifurcated, with two similar prongs ( Fig. 11 View FIGURE 11 B). Mesial inferior nematophore emerging from marked swelling at proximal third of internode ( Fig. 11 View FIGURE 11 D); with strongly developed nematotheca ( Fig. 11 View FIGURE 11 D, F). Hydrotheca elongate, roughly placed on middle of internode. Stony appearance. Abcauline wall straight, but convex at basal part. Hydrothecal aperture circular, roughly perpendicular to long axis of internode ( Fig. 11 View FIGURE 11 D–E, G); rim typically uneven, with slight adcauline elevation.

Gonothecae elongated with large subterminal aperture.

Remarks. The most striking feature of O. rigida is the strong stony appearance under SEM.

We have observed two axillary nematophores on every cauline apophysis examined ( Fig. 11 View FIGURE 11 B–C). Nevertheless, Peña Cantero et al. (1997) indicated that apophyses with a single axillary nematophore were also present. In this sense, it is worth mentioning that we have also observed a tendency to fusion of the two axillary nematophores.

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