New genus for a unique species of Indo-West Pacific bryozoan
Author
Tilbrook, Kevin J.
text
Zootaxa
2011
3134
63
67
journal article
45760
10.5281/zenodo.279480
de7db1a0-24e4-42d1-903b-f18fbe0cb493
1175-5326
279480
Tarsocryptus laboriosa
(
Tilbrook, 2006
)
comb. nov.
(
Figure 1
)
Biflustra reticulata
Tilbrook, Hayward & Gordon, 2001
: 38
, fig. 2E.
Aplousina laevigata
(
nomen nudem
):
Liu, Yin & Ma 2001
: 448
, pl. 17, figs 6, 7.
Biflustra reticulata
: Hayward 2001: 997
, fig. 2A,B.
Biflustra laboriosa
Tilbrook, 2006
: 20
.
FIGURE 1.
Tarsocryptus laboriosa
. MTQ G25162, Lizard Island. Scale 200µm.
Material.
Holotype
:
NHMUK
1998.8.4.66, Port Vila Harbour, Efate,
Vanuatu
.
Paratypes
:
NHMUK
1998.8.4.65, Port Vila Harbour, Efate,
Vanuatu
;
NHMUK
1998.8.4.288, Erakor Lagoon, Efate,
Vanuatu
, collected by D. P. Gordon.
Other material examined
: MTQ G25162, NW of Palfrey Island, Lizard Island,
14.68976º S
,
145.44014º E
.
Description.
Colony encrusting, up to
2–3 cm
2. Autozooids irregularly oval, 0.50–0.60 x
0.25–0.35 mm
, separated by shallow grooves. Gymnocyst minimal, varying in width, prominent proximally, but surrounding entire cryptocyst. Cryptocyst one third to one half of frontal area, extending to a greater or lesser extent either side of opesia, negligible distally, extensive proximally, flattened, smooth apart from a raised reticulate pattern of tubercles. Opesia oval to triangular (0.25–0.35 x
0.23–0.28 mm
). A pair of multiporous septula in each lateral wall, up to 10 uniporous septula in transverse wall. Basal wall generally entire but partially lacking in some autozooids. Cyphonautes larva transparent (0.30–0.40 x
0.25–0.30 mm
). Lophophore with 10 tentacles. Ancestrula ca
0.35 mm
long, identical in morphology to subsequent autozooids, giving rise to pair of a different-sized first-generation autozooids distolaterally.
Remarks.
This unique species is extremely distinctive with its relatively large cryptocyst bearing a reticulate ornamentation, obvious even on the ancestrula. Hayward (2001) noted that
Tarsocryptus laboriosa
larvae were collected during mid-September at Lizard Island and that they had all settled and metamorphosed within a day or two. Four days later, juvenile colonies were recorded, consisting of the ancestrula and two first-generation autozooids with an additional two zooidal buds. It is worth noting that
Liu
et al
. (2001)
found that colonies growing on the seagrass
Zostera japonica
had autozooids with a far greater range in size than those encrusting other substrata.
The need to reassign
Tarsocryptus laboriosa
has been apparent almost from the time of its first documentation. It is ironic that this newly documented species should be figured twice within the first year of its discovery, and these occurrences highlighted the need for a re-evaluation.
As explained by
Tilbrook (2006)
,
Liu
et al
. (2001)
recorded this species as ‘
Aplousina laevigata
Liu & Ristedt, 2000
’; however that epithet is a
nomen nudem
since the Liu & Ristedt paper recorded as ‘in press’ in the bibliography was never published.
Distribution
. Originally described from
Vanuatu
, where it was often found encrusting species of the calcareous green alga
Halimeda
,
Tarsocryptus laboriosa
has subsequently been found as a fouling species in the South
China
Sea and as a coral-reef associate at Lizard Island on the northern Great Barrier Reef. This known distribution suggests that this species should also be found within the wider Indo-Philippine region.