Buchneria Harmer, 1957

Hirose, Masato, 2012, Revision of the genus Buchneria (Bryozoa, Cheilostomata) from Japan, ZooKeys 241, pp. 1-19 : 3-6

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.

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.