An overview on the freshwater sponge fauna (Demospongiae: Spongillida) of New Zealand and New Caledonia with new insights into Heterorotula from deep thermal vents of the Lake Taupo
Author
Pronzato, Roberto
Author
Manconi, Renata
text
Journal of Natural History
2019
2019-12-18
53
35
2207
2229
journal article
24122
10.1080/00222933.2019.1694716
b21705d8-f93b-420c-a4b3-13f38a3ba0e7
1464-5262
3654895
Pachyrotula raceki
(Rützlerı 1968)
(
Figures 1
(B)ı
3
(F
–
G)ı
4
(C))
Spongilla
(
Stratospongilla
)
raceki
Rützlerı 1968
(figs. 5
–
9; p. 61)
;
Pachyrotula raceki
Volkmer- Ribeiro and Rützlerı 1997
;
Manconi and Pronzatoı 2002
;
van Soest et al.
ı 2018
Comparative materials
USNM
23882ı holotypeı
USNM
23883ı paratypeı several fragmentsı
Pachyrotula raceki
(as
Spongilla raceki
).
Description (emended after
Rützler 1968
)
Growth form encrustingı thin (
1 mm
thick)ı small (
1 cm
2) on the lower surface of stones. No oscula or inhalant apertures evident. Colour greyish-ochre (alcohol). Consistency soft. Spongin scanty. Skeleton is a dense polygonal meshwork of primary spicuları ascendingı paucispicular tracts (2
–
5 spicules)
100
–
200 µm
apart. Megascleres as microspiny oxeas (160
–
245 ×
7.5
–
10.5 µm
). Microscleres absent. Gemmules (
250
–
650 µm
in diameter) loosely scattered in the basal sponge portion. Gemmulosclere as birotules radially and irregularly arrangedı spiny shaft and distinguishing globular rotules irregularly spiny (
20
–
60 µm
in lengthı shaft
5.5
–
6.5 µm
in diameter; knobs
11
–
16 µm
in diameter).
Habitat
Tiny specimens of
Pachyrotula raceki
have been discovered in the Lac en Huit (Plaines des Lacsı 19.VII.
1965ı
coll. Dr. Ferdinand Starmuhlnerı Zoologisches Institut der Universität Wien) on boulders (
5
–
30 cm
depthı water temperature 21.50 °C). The pond also harbours the protected species of fish
Galaxias neocaledonicus
Weber & Beaufortı 1913
. In the middle course of the River Diahotı sponges have been found associated to
Oncosclera diahoti
(see above for environmental data). In the lower course of the River Diahot small flat sponges have been found on the lower surfaces of stones (water temperature 24.6°C) ~
10 km
upstream from the sea coastı an area still under the influence of the tidal backwater.
Figure 3.
Gemmuloscleres with divergent diagnostic morphotraits. Comparison of type specimens of the type species of the genera
Ephydatia
(A
–
B,
E. fluviatilis
),
Heterorotula
(C
–
E,
H. capewelli
),
Pachyrotula
(F
–
G,
P. raceki
) and
Oncosclera
(H
–
J,
O. jewelli
).
Geographic range
Pachyrotula raceki
is a New Caledonian endemics known only from three localities in two hydrographic basinsı i.e. middle course of the River Diahot (near Quéniaı Chapel St. Josephı North New Caledoniaı
16.IX.1965
); lower course of the River Diahot (next to the Bondé Mission houseı North New Caledoniaı
18.IX.1965
); Lac en Huitı (Plaines des Lacsı South New Caledoniaı
19.VII.1965
).
Remarks
Pachyrotula raceki
(
Holotype
USNM 2.3882) endemic to
New Caledonia
was firstly described as
Spongilla
(
Stratospongilla
)
raceki
by
Rützler (1968)
and later transferred to the new monospecific genus
Pachyrotula
by
Volkmer-Ribeiro and Rützler (1997)
. The most evident diagnostic trait of the genus is the unique gemmulosclere morph consisting of birotules ending in evident globular and irregularly spiny rotules (
Figure 3
(F
–
G)). Integrative taxonomy with also molecular analyses is necessary.