Rhizaxinella cf. nuda Wilson, 1925
publication ID |
https://doi.org/ 10.5281/zenodo.183878 |
DOI |
https://doi.org/10.5281/zenodo.6235809 |
persistent identifier |
https://treatment.plazi.org/id/03E887DC-5E75-FF99-5EC9-111DFB78A8A1 |
treatment provided by |
Plazi |
scientific name |
Rhizaxinella cf. nuda Wilson, 1925 |
status |
|
Rhizaxinella cf. nuda Wilson, 1925 ( Fig. 15 View FIGURE 15 )
Synonymy
Rhizaxinella nuda— Wilson 1925: 352 –353, pl. 38 (fig. 5).
Description
External morphology. Small clubshaped sponges with rather damaged stalks (figs. 15A–E). Their height varies from 0.6 to 2.1 cm. The surface is velvety, greyish. Consistency is rather soft. A contracted osculum is located slightly eccentrically on the top of main body.
Skeleton. The choanosomal skeleton is constituted by the principal tylostyles arranged more or less radially and grouped in tracts or bundles (fig. 15F). The ectosomal skeleton is formed by the bouquets of small tylostyles, densely packed and intermingled. Skeleton of the stalk not observed because of considerable damage of the latter.
Spicules. Altogether 120 spicules from 2 specimens were measured. Two size categories are well distinguished. The number of measured spicules of each category is given below, separately for each specimen (n1, n2).
Both principal and ectosomal spicules possess welldeveloped spherical tyles. Principal tylostyles are slightly fusiform and straight (fig. 15G). Their dimensions are: length 11501759 2318 µm, tyle diameter 17 18.921 µm, diameter of the shaft underneath the tyle 1314.315 µm, maximal diameter of the shaft 1316.2 21 µm (n1=30, n2=30). Ectosomal tylostyles are isodiametric, straight or slightly curved (fig. 15H). They measure: length 450551690 µm, tyle diameter 913.718 µm, diameter of the shaft underneath the tyle 7 9.011 µm, maximal diameter of the shaft 810.113 µm (n1=30, n2=30). Spicules of the stalk were not observed.
Type locality: NW Pacific: Philippines: Mindanau Island: Iligan Bay, 814 m.
Distribution (other than type locality): NW Pacific: Philippines: E. Cebu, 710 m ( Lévi 1964).
Antarctic: Northern Weddell Sea, 2080–2620 m (present study).
Remarks
We allocated the specimens studied to R. nuda due to the similarities of main body shape and skeleton architecture. However, it was done with some doubt because our sponges have smaller ectosomal tylostyles and thinner principal tylostyles than those described by Wilson (1925) and also we did not observe the stalk skeleton. On the other hand, our specimens differ quite noticeably from the Southern Hemisphere species R. australiensis Hentschel, 1909 . The latter is characterized by the branching, anastomosing body and smaller sizes of both principal and ectosomal spicules than those of the specimens described herein.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
Kingdom |
|
Phylum |
|
Class |
|
Order |
|
Family |
|
Genus |
Rhizaxinella cf. nuda Wilson, 1925
Plotkin, Alexander S. & Janussen, Dorte 2008 |
Rhizaxinella
Wilson 1925: 352 |