Aleutian Ancorinidae (Porifera, Astrophorida): Description of three new species from the genera Stelletta and Ancorina
Author
Lehnert, Helmut
Author
Stone, Robert P.
text
Zootaxa
2014
3826
2
341
355
journal article
45338
10.11646/zootaxa.3826.2.4
93379979-2e30-4117-a4fd-445b470d0ddd
1175-5326
230036
B70EC0BF-310D-43A6-90F1-7124BF39294D
Stelletta anthastra
n. sp.
(
Fig. 3
)
Material examined.
Holotype
,
USNM
1231429, in 70% ethanol, fragment of the
holotype
(
ZSM
20140114), in 70% ethanol. Collected by Brian Knoth with a research survey bottom trawl from the FV
Ocean Explorer
;
17 June
2012
, 225 m depth,
19.8 km
WNW of Carlisle Island in the Islands of Four Mountains, eastern Aleutian Islands, Bering Sea (
52°58.542” N
,
170°23.322” W
). Attached to a mass of sand and pebbles. Bottom water temperature = 3.9 °C.
FIGURE 3A–F.
Stelletta anthastra
n. sp.
A, Holotype, upper side. Grid marks are 1 cm. B, Holotype, obliquely from below. Grid marks are 1 cm. C, Holotype, section showing outer radial structure. Scale bar is 5 cm. D, Holotype, subsample showing radial structure, section perpendicular to c. Scale bar is 5 cm. E, Plagiotriaene. Scale bar is 100 µm. F, Anatriaene, note size difference to plagiotriaene. Scale bar is 20 µm.
FIGURE 3G–J.
Stelletta anthastra
n. sp.
G, Oxyasters and anthasters. Scale bar is 10 µm. H, Oxyasters. Scale bar is 2 µm. I, Anthasters. Scale bar is 2 µm. J, Anthasters around unidentified diatom. Scale bar is 10 µm.
Description.
Large, massive, whitish (in life), ovoid sponge, approximately
18.5 cm
x
15
cm
x
12
cm, hard, only slightly elastic consistency, no oscules visible. The surface is covered by many low elevations, similar to a cauliflower (
Figs. 3A & B
). Many small openings are visible under low magnification (
16 X
). We are not sure whether these openings are pores or oscules but they are ungrouped and scattered over the entire surface without any obvious pattern. In sections perpendicular to the surface the radial arrangement of polyspicular tracts, consisting of different triaenes and oxeas is visible with the unaided eye (
Figs. 3B–D
) as the tracts are
4–5 cm
long. These tracts start in the interior with a diameter of
1 mm
and fan out at the surface to a diameter of
4–10 mm
and support the surface elevations which have the same diameters and height of
2–4 mm
. The cortex is
8–10 mm
below the surface (
Fig. 3D
). Spicules are ortho- to plagiotriaenes (
Fig. 3E
), straight rhabds, 680–910 x 112–115 µm, recurved clads, 480–500
x 90
–100 µm, occasionally with one or two reduced clads; very long, thin anatriaenes (
Fig. 3F
), up to 19,000
x 30
µm and a short cladome with clads, 180
x 20
µm, oxeas, 9500–11,900
x 50
–120 µm, oxyspherasters (
Figs. 3G–H
), the distal end looks inflated because of a concentration of spines there, 14–20 µm in diameter, and anthasters (
Figs.
3I
–J
) with spiny ends of rays, 5–8 µm in diameter.
Discussion.
Stelletta anthastra
n. sp.
differs from all other known species of
Stelletta
(
Table 1
) and differs from
S
.
makushina
n. sp.
in having shorter triaenes, extremely long anatriaenes up to
19 mm
in length, much longer oxeas, larger, differently shaped oxyasters and an additional category of anthasters.
S
.
ovalae
Tanita 1965
also has very long megascleres but it differs in having dichotriaenes lacking in
S
.
anthastra
and in the categories of asters.
S
.
ovalae
has two size categories of oxyasters while
S
.
anthastra
has one category each of oxyaster and anthaster.
S
.
rhaphidiophora
Hentschel 1929
(
Table 1
) also has very long megascleres but differs in having dichotriaenes, a second category of oxyasters instead of the anthasters present in
S
.
anthastra
, and in having bundles of rhaphids.
S
.
splendens
Tanita, 1965
is the only other species of
Stelletta
where “three-rayed” anthasters are described with spiny rays,
95 x 25
µm. These clearly differ in size and dimensions from the anthasters described here. We question whether the three-rayed anthasters described for
S
.
splendens
are indeed anthasters.
Etymology.
Named after the beautiful anthasters that occur in this species.