Revision of the genus Buchneria (Bryozoa, Cheilostomata) from Japan
Author
Hirose, Masato
text
ZooKeys
2012
241
1
19
http://dx.doi.org/10.3897/zookeys.241.3175
journal article
http://dx.doi.org/10.3897/zookeys.241.3175
1313-2970-241-1
Genus
Buchneria Harmer, 1957
Type species.
Palmicellaria dofleini
Buchner, 1924 by original designation by Harmer (1957: 876) (=
Escharoides teres
Ortmann, 1890).
Diagnosis.
Colony erect, rigid, dichotomously or irregularly branching: branches cylindrical, flattened, or plate-like, fan shaped. Zooidal frontal shield uniformly tessellated, with a few areolar pores near margin or offset centrally in secondarily calcified wall. Orifice deeply immersed, without teeth on distal periphery, without lyrula or condyles, slightly concave or straight proximally; oral spines absent. Secondary orifice at colony surface cormidial, formed by contributions of secondary calcification from distal and lateral zooids. Suboral avicularium lies at proximal margin of secondary orifice, directed proximally or laterally, sometimes enlarged and occupying about half of frontal shield; small, conical tooth associated with avicularium projecting into secondary orifice (Fig. 2). Mandible of the suboral avicularium semicircular or spatulate, but never acute. Vicarious and other frontal avicularia absent. Ovicell globose, acleithral, and is produced by the distal zooid (Fig. 3). Both the endooecium and ectooecium are calcified. Endooecium is completely calcified, whereas ectooecium is not completely covering the endooecium (Fig. 3A, B). Immediately after formation, the ectooecium is then partially covered by the secondary calcification that is coming from the distal and neighbour zooids (Fig. 3B). Finally, the secondary calcification covers most of the ectooecium in the old parts of the colony, but a small area of proximal margin remains uncovered (Fig. 3C). Small basal pore chambers present.
Figure 2. Orifices of three
Buchneria
species showing the small tooth distal to the suboral avicularium. A
Buchneria teres
B
Buchneria rhomboidalis
C
Buchneria variabilis
.
Figure 3. Ovicells of
Buchneria teres
showing various stages of development. A Younger stage ooecium showing smooth surface of endooecium and ectooecium with less secondary calcificationB Ooecium started covered by tessellated secondary calcification from neighboring zooidsC Ooecium almost covered by the secondary calcification with showing endooecium through the small proximal membranous window at ectooecium. Ec, ectooecium; En, endooecium; Sc, secondary calcification. Arrows indicate the proximal membranous window.
Remarks.
Harmer (1957)
defined
Buchneria
as follows: colony erect, not jointed; large spatulate avicularia present; zooids with a
"sinuate"
or nearly straight proximal margin of the orifice (the term
'sinuate'
appears to be misapplied to the evenly concave proximal margin in
Buchneria sinuata
; perhaps Harmer intended the meaning as 'having a
sinus'
); small, acute suboral or lateral avicularia on the edge of the secondary orifice; few frontal pores; and a hyperstomial ovicell with an imperforate central tabula.
His
generic diagnosis, however, largely derives from
Buchneria sinuata
Harmer, 1957 from Indonesia. This species is similar to the three
Buchneria
species treated herein in having erect colony form, few frontal or marginal pores, and a deeply immersed primary orifice. However, it differs substantially from them in having large, spatulate frontal avicularia; hyperstomial ovicells with an imperforate central tabula lacking secondary calcification; and a laterally placed, acute oral avicularium (Harmer, 1957: plate LIV, fig. 19).
Buchneria sinuata
, therefore, has currently been thougth to belong in another genus, perhaps
Osthimosia
Jullien, 1888 (Gordon, 1984).
Gordon (1984)
noted several similarities between
Osthimosia virgula
and nominal
Buchneria sinuata
(e.g., broad orificial sinus, a lateral-oral avicularium on peristome, and spatulate frontal avicularia), and
suggested
the two species may be congeneric. Subsequently,
Gordon (1989)
observed and illustrated Japanese material of
Buchneria
present in the Natural History Museum London (NHMUK), and elucidated the umbonuloid frontal shield; he concluded
Buchneria
cannot be grouped together with
Osthimosia
and other lepraliomorphs. Unfortunately, I have never had a chance to check the type material of
Harmer's
Buchneria sinuata
, which is not in NHMUK (Mary Spencer Jones, pers. comm. 11 May 2012) and both institutes Zoological Museum Amsterdam (ZMA) and Naturalis Biodiversity Center in Leiden (Elly Beglinger, pers. comm. 19 September 2012). Although I have not checked the type material, I exclude
Harmer's
Buchneria sinuata
from the description of the genus in this paper based on the significant differences with the type species of the genus;
Buchneria sinuata
is also different from other
Buchneria
species in mainly imperforate frontal shield, small colony size, and preference of unstable substrate which is unusual for
Buchneria
species. The status of
Buchneria sinuata
is still unclear and should be clarified in future work. With the removal of nominal
Buchneria sinuata
from
Buchneria
, the cormidial orifice and the rounded mandible of suboral avicularia may be considered diagnostic characters for
Buchneria
.
Buchner (1924)
described large frontal avicularia, but these are enlarged suboral avicularia; therefore, absence of a large frontal avicularium may also be considered diagnostic for
Buchneria
.
Gordon (1989)
regarded
Buchneria
close to
Celleporaria
in
Lepraliellidae
, based on the similarities between the type species of both genera in the umbonuloid and imperforate frontal shield with marginal areolar pores, broad orifice, and suboral avicularium. However, the ovicell of
Buchneria
is different from that of
Lepraliellidae
in having broader proximal window and deeper ooecium, and is more similar to that of
Palmiskenea
Bishop & Hayward, 1989 in
Bryocryptellidae
with a few small foramina close to the proximal margin.
Buchneria
also resembles
Palmiskenea
in the frontal shield having only marginal areolar pores, but differs from the latter in the orifice without condyles and in polymorphic avicularia.
Buchneria
resembles
Marguetta
Jullien, 1903 in having only marginal pores, an ovicell with a few small pores, and oval suboral avicularia, but differs from the latter in lacking frontal avicularia on margin of the frontal shield.
Buchneria
also resembles
Porella
Gray, 1848 and
Porelloides
Hayward, 1979 in having only marginal pores, an ovicell without or with a few small pores, and suboral avicularia, but differs from the latter two genera in lacking lyrula and condyles. Although some species of
Porella
also lack a lyrula, and species of
Porelloides
normally lack condyles, a small tooth on the distal margin of the suboral avicularium is characteristic of
Buchneria
. Considering the similarities of ovicell and orifice morphology between
Buchneria
and the four bryocryptellid genera,
Porella
,
Palmiskenea
,
Marguetta
and
Porelloides
, I conclude
Buchneria
is much better placed in
Bryocryptellidae
rather than
Lepraliellidae
.
Harmer (1957)
suggested that
Haswellia auriculata
Busk, 1884 be placed in
Buchneria
, on the basis of orifice morphology and the small lateral avicularia on the edge of the peristome. He also suggested that the species
Haswellia auriculata
and
Myriozoum marionense
Busk, 1884 as described by Calvet (in
Jullien and Calvet 1903
) represent a single species referable to
Buchneria
, on the basis of very few frontal pores; a large, spatulate frontal avicularium; the form of the peristome with small avicularia; and i
mmersed
ovicells (Harmer, 1957). However,
Haswellia auriculata
is currently regarded as a junior synonym of
Galeopsis pentagonus
(
d'Orbigny
, 1842), and the specimen described as
Myriozoum marionense
in
Jullien and Calvet (1903)
is also considered as a species of
Galeopsis
.
Excluding nominal
Buchneria sinuata
,
Buchneria
presently contains three species, which I redescribe here.