Boninastrea, YABE & SUGIYAMA, 1935: 402

Huang, Danwei, Benzoni, Francesca, Fukami, Hironobu, Knowlton, Nancy, Smith, Nathan D. & Budd, Ann F., 2014, Taxonomic classification of the reef coral families Merulinidae, Montastraeidae, and Diploastraeidae (Cnidaria: Anthozoa: Scleractinia), Zoological Journal of the Linnean Society 171 (2), pp. 277-355 : 299-300

GENUS BONINASTREA YABE & SUGIYAMA, 1935: 402 ( FIG. 6 )

Type species

Boninastrea boninensis Yabe & Sugiyama, 1935: 402 , pl. 10: figs 1, 2; original designation, Yabe & Sugiyama, 1935: 402.

Original description

‘Corallum compound, massive; calicular surface strongly convex. Epitheca indicated by fine ringlets of growth, thin, conspicuous, covering almost entirely underside. Calices numerous, subpolygonal, irregular in shape and arrangement oblique; usually one to three or more in number circumscribed in group by incomplete, oblique collines. Occasionally several of the groups are further bounded by prominent, incomplete, oblique ridges. In each group calices connected by trabecular bridges instead of toothed lamellae. Septa not numerous, up to three cycles, those of the first and some of the second cycles more stout and more prominent than others; their free ends strongly divided in irregular manner, to filiform processes. Surface of septa minutely granulated. Columella absent? Dissepiments numerous, vesicular. Growth by fission.’ ( Yabe & Sugiyama, 1935: 402).

Subsequent descriptions

Yabe et al., 1936: 45; Vaughan & Wells, 1943: 190; Wells, 1956: F416; Veron, 1986: 594; Chevalier & Beauvais, 1987: 721; Best & Suharsono, 1991: 339; Veron, 2000, vol. 2: 382.

Diagnosis

Colonial, with intracalicular budding only. Corallites monomorphic and uniserial; monticules absent. Walls fused. Calice width medium (4–15 mm), with medium relief (3–6 mm). Costosepta confluent. Septa in <three cycles (<24 septa). Free septa present but irregular. in Japan (type locality) and Indonesia, and never for molecular analysis. We do not have sufficient data to place it on the tree, but note that it has been described as a ‘mussoid [sic] coral, recalling Symphyllia and Isophyllia in general feature’ ( Yabe & Sugiyama, 1935: 402), but later placed in Merulinidae (prior to Budd et al., 2012) by Veron (1986: 594), Best & Suharsono (1991: 339), and Veron (2000, vol. 3: 382).

Boninastrea is known only from its type locality, the Ogasawara Islands of Japan , as well as Sumbawa ( Best & Suharsono, 1991), Gulf of Tomini , Banda Sea, and the Moluccas of Indonesia.

Morphological remarks

In comparison with genera that were in Merulinidae before Budd et al. (2012), it does not appear to share the small calice width, low relief, equal costosepta thickness, well-developed paliform lobes, absence of epitheca, and sparse endotheca with Merulina and Scapophyllia . Its size and lack of lobes are akin to most Hydnophora spp. , and the ‘prominent, incomplete, oblique ridges’ are analogous to monticules of Hydnophora , but homology cannot be ascertained without further sampling.

Septa spaced six to 11 septa per 5 mm. Costosepta unequal in relative thickness. Columellae trabecular but compact (one to three threads) or absent, <1/4 of calice width, and continuous amongst adjacent corallites. Paliform (uniaxial) lobes weak or absent. Epitheca well developed and endotheca abundant (vesicular) ( Fig. 6 ).

Species included

Boninastrea boninensis Yabe & Sugiyama, 1935: 402 , pl. 10: figs 1, 2; holotype: TIU 44970 (dry specimen; Fig. 6 ); type locality: Futami-wan , Titi-zima, Ogasawara Islands, Japan; phylogenetic data: none.

Taxonomic remarks

Boninastrea Yabe & Sugiyama, 1935: 402 , is a monotypic genus that has only been collected twice, once each

Figures

Figure 6. Boninastrea Yabe & Sugiyama, 1935, has uniserial corallites, fused walls, septa in <three cycles (<24 septa), unequally thick costosepta, rudimentary columellae, and abundant (vesicular) endotheca. A, B, Boninastrea boninensis Yabe & Sugiyama, 1935, the type and only living species of Boninastrea; macromorphology, holotype TIU 44970, Ogasawara Islands, Japan.