Systematics of interstitial encrusting bryozoans from southeastern Brazil
Author
Winston, Judith E.
Author
Vieira, Leandro M.
text
Zootaxa
2013
3710
2
101
146
journal article
10.11646/zootaxa.3710.2.1
867ca84b-ed17-40e4-a603-b2efd0e6fef3
1175-5326
248125
6E42B926-DAA9-4BAE-B995-8BDB19B93268
Psammocleidochasma tridentatum
sp. nov.
(
Fig. 21
;
Table 19
)
TABLE 19.
Measurements (in mm) of
Psammocleidochasma tridentatum
sp. nov.
.
|
Lz
|
Wz
|
Lo
|
Wo
|
Lov
|
Wov
|
| N |
13 |
13 |
11 |
11 |
2 |
2 |
| Mean |
0.242 |
0.195 |
0.066 |
0.056 |
0.117 |
0.162 |
| SD |
0.022 |
0.049 |
0.012 |
0.007 |
0.013 |
0.000 |
| Min |
0.216 |
0.126 |
0.054 |
0.045 |
0.108 |
0.162 |
| Max |
0.288 |
0.306 |
0.090 |
0.072 |
0.126 |
0.162 |
Material examined.
Holotype
: MZUSP 746 (
Fig. 21
A, E), BIOTA Stn 211.
Paratypes
: MZUSP 691, specimen #20, near BIOTA Stn 205, 15 m; MZUSP 692, #21 [7 colonies], near BIOTA Stn 205, 15 m; MZUSP 747, specimen #3, BIOTA Stn #3; MZUSP 748 (
Fig. 21
F), BIOTA Stn 205; MZUSP 749, measured specimen #1, BIOTA Stn 205; VMNH 70028, measured specimen #2, BIOTA Stn 205; VMNH 70029, BIOTA Stn 205; VMNH 70030, BIOTA Stn 205.
Additional material
: MZUSP 693, #22 [several colonies], near BIOTA Stn 205, 15 m; MZUSP 711, BIOTA Stn 211.
Supplementary video.
http://cifonauta.cebimar.usp.br/taxon/psammocleidochasma-tridentatum/
Etymology.
Latin,
tridentatum
, three-toothed, aluding to the three tubercles, one proximal and two lateral, which adorn the peristome.
Diagnosis.
Sand-encrusting
Psammocleidochasma
with 3 peristomial tubercles arranged laterally and proximally.
Description.
Colony encrusting on sand grains, including very small mineral grains. Zooids oval, convex, frontal shield smoothly and thickly calcified, imperforate except for a very few small marginal pores; zooid margins indistinct. Distal end of zooids raised in a thick collar made up of a very thick proximal tubercle and 2 lateral tubercles. Orifice keyhole shaped, anter transversely oval, ending in two rounded, proximomedially pointed condyles, poster a narrow to broad, shallowly concave sinus. Articulated oral spines 2–3, often obscured by distal calcification. No avicularia. Reproduction precocious; ovicells may occur only 2 zooids from ancestrula. Ovicells thickly calcified, with a central tubercle and vertical proximal wall ending in an opening that is separate from the operculum. Ancestrula tatiform with a thick mural rim and 5 hollow spines. Polypides with 7–8 translucent white tentacles.
Remarks.
This species prefers the ridges and raised edges of grains, including very small and sharp-edged mineral grains. It is the most abundant species found encrusting sand in the Brazilian fauna. The Brazilian species is very similar to the interstitial Floridan species
Psammocleidochasma angustum
, however that species has four peristomial tubercles, arranged distolaterally and proximolaterally along the rim of the peristome.
Distribution.
São Paulo state,
Brazil
.