Table Of ContentRev. Mus. Argentino Cienc. Nut., n.s.
4(2): 187-19 0,2002
Buenos Aires, ISSN 1514-5158
Smiltina obEita sp. nov., a new cheilostomatous bryozoan
from the southwest &lalatie
Juan LOPEZ GAPPA
Museo Argentina de Cicncias Naturalos 2uBcrnardino Rivadavia,,, Av. A. Gallardo 470, C14051)JR Buenos Aircs,
Argentina. E-mail: [email protected]
Abstract: The cheilostomalausb ryozaanSnriltina oblila sp.n ou is described fromsampic-,~ <>liectedthine Patagonian
Shelf and tho Burdwood Bank (southwest Atlantic Ocean). 'This new species seems to be reiated to Smiitina lebruni
(Waters, 1905),a nd Smilhna atitarctico (Waters, 1904), from which it differsi n its charact*ristic suboral avicularin.
Key words: Sir~illinan, ew species, cheilostomalous Bryozoa, Argentina, southwest A1I;iirtic Ocean.
Smittinids are one of the most diversified groups distinct sutures (Fig. I). Frontal wall finely granu-
of cheilostomatous bryozoans, with around 25 gen- lar, perforsted by relatively few, evenly distrib-
era (D. P Gordon, pers. comm.) and more than 300 uted, large and rounded pores. Primary orifice
species throughout the world oceans. As well as in wider than lo@%d, istal border straight and finely
many other cheilostome taxa, specific richness denticillat# (Fig. 2). Lyrula short and very broad,
within this finlily was w,nsisteiitly underestimated occupying most of the proximal border of the ori-
by earlier authors. Morpholopcal features used to fice. Two distolateral oral spines present in early
characterize smittinid species are often subtle, and untogeny, later obscurcd by the development of
can be clearly discerned only by scanning electron the peristome. Peristome well developed, tubular,
microscopy As a consequence, some species for- protruding over the surface of the autozooid, grow-
merly regarded as widely-distributed, actually in- ing medially and fusing above the avicularium to
cluded several more or less enclemic taxa. Modern delimit a large roiind foramen (Fig, 3). All
studies devoted to this family (e.g., Soule & Soule, autozooids with one suboral avicularium situated
1973; Hayward & Thorpe, 1990) described a high immediately proximal to peristomial foramen.
proportion of new species, suggesting that more Most avicularia long and slender, crossbar slen-
smittinids still remain to be discovered. der and complete, with a poorly developed col-
The genus Smittina Norman is represented in umella; opesia small and rounded; palate almost
the continental shelf'offArgentina by at leata dozex~ entire, with a crescentic foramen below the cross-
species (see Hayward & Thorpe, 1990; reviewed in bar (Fig. 1). Mandible of the avicularium long,
L6pez Gappa, 20001, most of which have a Magel- slender and blunt. This avicularium is replaced
lanic distribution, being present in cold-temperate in some autozooids by a large, spatulate one, with
waters around the southern tip of South America. a well chiiinized mandible, almost reaching the
The aim ofthis study is to describe a new spe- orifice of the proximal zooid (Fig. 5). Ovicell
cies of the genus Smittina discovered in several rounded, broader than long, perforated by several
samples from the Patagonian Shelf and the irregularly rounded frontal pores, recumbent over
Burdwood Bank, which had not been found previ- the frontal wall of the distal zooid during early
ously in the area in spite of the exhaustive collec- ontogeny, later becoming more or less immersed
tions of smittinid brymoans gathered by British (Fig. 6). Peristome extending on to frontal sur-
expeditions in Antarctic and sub-Antarctic regions race of ovicell.
(Hayward & Thorpe, 1990).
Material
Smittina oblita sp. nou. Holotype: MACN-In 34990, RN Orient Maru
(Figs. 1-61 I, station 39, 21/03/76, 50" 35'S, 63" 14' W, 150-
152 m. Collected by R. Menni. Growing around a
Description hydroid stem.
Colony encrusting, unilamina~: Autozooids I'aratypes: WCN-ln 34991, ARAlslas Orca-
oval to hexagonal, slightly convex, separated by $as, between 50' 40' S, 58" 04'W and 50" 54' S, 58"
188 Reuzsta del Mweo Argent~nod e Cze~
Figs. 1-6. Sn~ittinao blita sp. rlou., MACN-In 32359. 1, General view of several zooids, three of them
oviceiled. 2, Zooid from the colony margin, showing oral spines and primary orifice during early on-
togeny. 3, One zooid, showing peristome and subora1 avicularium. 4. Detail of the most common type
of suboral avicularium. 5, One zooid bearing a spat. ulate avicularium. 6, Detail of avicell. All scales
represent 0.2 mm.
Lipez Gappa: A new bryozoarz from the southwest Atlantic 189
10' W, 128-132 m, 08/02/76. Collected hy N. ' i ?- bi - 35'
Cazzaniga. Growing on a hilaminar colony of
Smittina lebruni. a
r--1 - 37'
Other material: MACN-In 32405-1, 32389-1
&,"
and 32394-1, same locality as paratypes. MACN-
In 32359-1, FNApi IV, near the Beagle Channel, - 3y1
'rierra def Fuego, Octoherl78. R,W Shirtkai Maru (\.-$
41'
Cruises: SM IV, station 71,48" 30'S, 62" 31'W, 141
rn,2 8/07/78. SM IV; station 92,50" 30' S, 62" 31'w 'y I
i
159 m, 14/08/78. SM IY station 108, 52" 31'S, 67" < 4 3
18'W, 92 m, 11/08/78. SM rV; station 111, 52" 29' Atlantic
S, 64" 35' W, 183 m, 12/08/78. SM n! station 119, Ocean 1- 45"
53" 31.' S, 66" 27'W, 95 m, 10/08/78. SM \! station
79, 49" 27' S, 62" 29' W, 152 m, 09/09/78. SM \!
- 4.7'
station 101, 51" 30'S, 65" 32' W, 134 m, 07/09/78. jJm
SM V; station Ad. 3,49" 26'S, 63" 27'W, 14!5 m, 051
9
09/78. SM X, station 135,54" 30'S, 68" 30'K 133 E? 4Ys
rn ma
m, 63/02/79. SM X, station 138, 54" 30'S, 56" 35'
W, 135 m, 02/02/79. SM XI, station 68, 48" 27' S, @k! El -51'
6.F 27'W, 103 m, 05/03/79. o;"$p
la m-
.Ueasurements imm, mean (m~nlmum- maxi-
mumll.
,
Autozooid length: 0.66 (0.46 - 0.83), n = 20.
Autozooid width: 0.35 (0.27 - 0.461, n = 20. LengLh
of secondary orifice: 0.13 (0.10 - 0.16), n = 20.
Width of secondary orifice: 0.18 (0.11 - 0.22), n = 70' 68' 66' 64" 62' 60' 5V 56' 54" 5Zr 50'
20. Oviccll length: 0.20 (0.17 - 0.24), n = 5. Ovicell
width: 0.36 (0.29 - 0.40), n = 5. Avicularium length Fig. 7. Geographic distribution orsnittinu oblila
(slender): 0.18 (0.14 - 0.23), n = 20. Avicularium sp. nol;.
len&'th (spatulate): 0.31 (0.26 - 0.34), n = 3.
Etymology
hydroa)r.alErrinupsis reticulum, and zoaria of the
From Latin oblitus, -a, -um, fbrgotten.
erect hryozoans Aspidostoma giganteum,
Smittina lebruni, Ogiualia elegans and Hornera
Distribution
sp. Colony size ranged from 1.4 to 13.3 mm.
Patagonian shelf off Santa Cruz and Tierra dei
Ovicells dL,ring all months in wKlch
Fuego Provinces (Argentina), Burdwood Bank, samples were ( ~ ~~ h ~ju~ly ~~ ~~ ~h ~ , ,
and north of Malvinas (FalMand) Islands (Fig. 7).
through
Obseruatlons
ACKNOWLEDGEMENTS
This new species seems to he closely related
both to the Magellanic Smillina lebruni Waters,
I am gratcliil to NBstor Landoni for his help,
1905), and LoSmittina antarctica (Waters, 1904),
to Adriana Oliva for her expertise and advice in
an endemic Antarctic species (Hayward, 1995),
Latin, to Ricardo Bastidafbr the loan of the speci-
from which it differs in its characteristic
mens collected by the RN Shinhai Maru, and to
avicularia, form orcolony growth and presence or
Patricia L. Cook for her helpful suggestions to the
oral spines. S: oblita also diffirs fromS. antizrz.tica
original manuscript. 'She National Council for
in the presence of distal oral crenulations and a
Scientific Research and Technolow of Argentina
-"
peristomial foramen.
(CONICET) provided financial support during
The most common type of avicularium of
this study,
Smittina oblita is remarkably similar to that of
Smittoidea curtisensis Gordon, 1984, a New
BIB1,IOGRAPHY
Zealand smittinid.
Smittina oblita was found growing around
Gordon. D.E 1984. Tho marine fauna of New Zealand:
II , p tI ~ sIl 'r. I,.!~.i.:. i:~!I~. i~:j~,,i.il.y~:rlii.~t.t..:l~!tI i.rr,I ri 1~.1 ill.:,.i~.;-.L :!.,C .i,. . ,Z . . I .I . . ...:.I. ,:.. Ii. ,..::ii .:I. Ki.l,:u .: i1c7 . I!. I..,.
190 Reocstu del Mweo Argentzno de Ccenccns Naturules, n s 4 121, 2002
tion of Hawaiian and Easlern Pacific Smittiriidae
(Bryozoa, Ectopracta). Bull. Am. Mus. Nut. Hisl.
152: 365-440.
-sub-Antarctic s'pe cik of Smittinidae (Bryozoa:
Cheilostornata). Zool., Loud. 222: 137-175.
L6pez Gappa, 3. 2000. Species richness ol' marine
Bryoaoa in the continental sholf atid slope off Ax- Land., Zuol. 29: 230-251.
gentins (south-west Azlantic). Diu Disir 6: 15-27. Recibido: 18-VI-2002
Soulc, DE & J.D. Souie. 1973. Morphology and specia- Acaptado:1 5-VIII-2002
