Oulophyllia, MILNE EDWARDS & HAIME, 1848

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 : 328-330

GENUS OULOPHYLLIA MILNE EDWARDS & HAIME, 1848 A: 492 ( FIG. 19 )

Synonyms

Coelogyra Nemenzo, 1959: 109 (type species: Coelogyra levis Nemenzo, 1959: 109 ; pl. 8: fig. 2; original designation, Nemenzo, 1959: 109); Ulophyllia Milne Edwards & Haime, 1857, vol. 2: 377 (type species: Meandrina crispa Lamarck, 1816: 247 ; original designation, Milne Edwards & Haime, 1857, vol. 2: 378).

Type species

Meandrina crispa Lamarck, 1816: 247 ; original designation, Milne Edwards & Haime, 1848a, vol. 27: 492.

Original description

‘Diffère du précédent [ Tridacophyllia = Pectinia ] par des murailles beaucoup moins élevées, par la présence d’une columelle spongieuse bien marquée, et par des cloisons très-granulées dont le bord est très-profondément divisé, surtout inférieurement.’ ( Milne Edwards & Haime, 1848a, vol. 27: 492).

Subsequent descriptions

Milne Edwards & Haime, 1849a, vol. 11: 268; d’Orbigny, 1851: 168; Milne Edwards & Haime, 1857, vol. 2: 377, 378; Quenstedt, 1881: 1010; Duncan, 1884: 94; Quelch, 1886: 88; Delage & Hérouard, 1901: 627; Matthai, 1928: 256; Yabe et al., 1936: 42; Vaughan & Wells, 1943: 169; Alloiteau, 1952: 617; Crossland, 1952: 146, 147; Wells, 1956: F402; Wijsman-Best, 1972: 49; Chevalier, 1975: 160; Veron et al., 1977: 117; Scheer & Pillai, 1983: 127; Wood, 1983: 155; Veron, 1986: 498; Chevalier & Beauvais, 1987: 716; Sheppard, 1990: 14; Sheppard & Sheppard, 1991: 134; Veron, 2000, vol. 3: 195.

Diagnosis (apomorphies in italics)

Colonial, with intracalicular budding only. Corallites monomorphic and discrete (one to three centres) or uniserial; monticules absent. Walls fused. Calice width medium (4–15 mm), with medium relief (3–6 mm). Costosepta confluent. Septa in three cycles (24–36 septa). Free septa present but irregular. Septa spaced <six septa per 5 mm. Costosepta equal in relative thickness. Columellae trabecular and spongy (> three threads), <1/4 of calice width, and continuous amongst adjacent corallites. Paliform (uniaxial) lobes weak or moderate. Epitheca absent and endotheca abundant (vesicular) ( Fig. 19A, D, G ).

Tooth base at midcalice circular. Tooth tip at midcalice irregular; tip orientation perpendicular to septum. Tooth height medium (0.3–0.6 mm) and tooth spacing medium (0.3–1 mm), with> six teeth per septum. Granules scattered on septal face; irregular in shape. Interarea palisade ( Fig. 19B, E, H ).

Walls formed by dominant paratheca; abortive septa absent. Thickening deposits fibrous. Costa centre clusters not distinct; medial lines strong. Septum centre clusters not distinct; medial lines strong. Transverse crosses present. Columella centres clustered ( Fig. 19C, F, I ).

Species included

1. Oulophyllia crispa ( Lamarck, 1816: 247) ; holotype: MNHN IK-2010-526 (dry specimen; Fig. 19A ); type locality: ‘lOcéan indien?’ ( Lamarck, 1816: 247); phylogenetic data: molecular and morphology.

2. Oulophyllia bennettae (Veron, Pichon & Wijsman- Best, 1977: 73, figs 138–144, 445–448); holotype: NHMUK 1977.1 .1.3 (dry specimen; Fig. 19D ) ; paratype: MTQ G59712 (dry specimen) ; paratype: RMNH 10735 (dry specimen); type locality: Falcon Island , Palm Islands, Australia, 5–10 m depth; phylogenetic data: molecular and morphology .

3. Oulophyllia levis ( Nemenzo, 1959: 109; pl. 8: fig. 2); holotype: UP C-412 (dry specimen; Fig. 19G ); type locality: Pinamungajan , Cebu, the Philippines; phylogenetic data: none .

Taxonomic remarks

Oulophyllia Milne Edwards & Haime, 1848a , vol. 27: 492, is a small genus that has been recovered genetically as a well-supported clade ( Fukami et al., 2004a; Huang et al., 2009, 2011; but see Fukami et al., 2008; Arrigoni et al., 2012). It was established for the type species Oulophyllia crispa , and compared with Pectinia it was found to have lower walls and more spongy columellae ( Milne Edwards & Haime, 1848a, vol. 27: 492). The walls of Pectinia however refer to laminae that project upwards and may contain corallites formed by budding. Their corallites are organically united and thus the laminae may not be considered homologous to the walls of Oulophyllia , or other discrete or uniserial taxa. In spite of this, the two genera are indeed closely related, and together with Caulastraea and Mycedium form a well-supported molecular clade ( Fukami et al., 2008; Huang et al., 2011; Arrigoni et al., 2012).

Only Oulophyllia crispa and Oulophyllia bennettae have been studied phylogenetically. The third species, Oulophyllia levis , is very similar to the type in terms of macromorphology, differing only in having smaller valleys and less developed columellae ( Veron, 2000, vol. 3: 198). In fact, it was originally described as having no columellae, with a ‘loose mass of septal spines’ in its place ( Nemenzo, 1959: 109), thus expanding the morphological range specified by Milne Edwards & Haime (1848a, vol. 27: 492).

Oulophyllia is widely distributed on reefs of the Indo- Pacific, and absent eastwards from Hawai’i.

Morphological remarks

Oulophyllia is supported by a decay index of 2 on the morphological phylogeny, and the singular synapomorphy detected is wall fusion (likelihood of 0.98 based on the Mk1 model). The two-step change from moderate coenosteum to fused walls at its most recent common ancestor with Caulastraea accounts for the decay index of 2 despite having only one synapomorphy.

The genus is frequently associated with Favites and Platygyra , primarily because of their cerioid corallites ( Vaughan & Wells, 1943: 169; Veron, 1986: 498, 2000, vol. 3: 195). The phylogeny based on both molecular and morphological evidence clearly shows this trait arising at least three times independently within Merulinidae , in the lineages represented by Favites + Platygyra , Coelastrea , and Oulophyllia . The initial placement of Oulophyllia bennettae in Favites also underscores the homoplastic nature of this character (see remarks for Favites above).

Another homoplastic character exemplified by this genus is corallite integration, which is polymorphic in this genus (uniserial in Oulophyllia crispa and Oulophyllia levis ; discrete in Oulophyllia bennettae ), Goniastrea , and Platygyra .

Amongst close relatives, these features may still be useful distinguishing characters, separating Oulophyllia from Caulastraea (phaceloid) and Pectinia + Mycedium (extensive coenosteum), as well as Oulophyllia and Caulastraea from Pectinia + Mycedium (organically united corallites). Few subcorallite characters are distinct for Oulophyllia within this clade, but a combination of medium tooth height (0.3–0.6 mm), more than six teeth per septum, palisade interarea, and transverse septal crosses would be diagnostic.

Figures

Figure 19. Oulophyllia Milne Edwards & Haime, 1848a, has fused walls, medium-size (4–15 mm) and medium-relief (3–6 mm) calices, septa spaced <six septa per 5 mm and abundant (vesicular) endotheca. Septal teeth with medium height (0.3–0.6 mm) and spacing (0.3–1 mm). Walls formed by dominant paratheca, with strong costal and septal medial lines, and transverse septal crosses. A–C, Oulophyllia crispa (Lamarck, 1816), type species of Oulophyllia; macromorphology, holotype MNHN IK-2010-526, unknown locality (A); micromorphology (scanning electron microscopy; B) and microstructure (transverse thin section; C), hypotype UF 2104 (FA1070), Palau. D–F, Oulophyllia bennettae (Veron, Pichon & Wijsman- Best, 1977); macromorphology, holotype NHMUK 1977.1.1.3, Falcon Island, Australia (D); micromorphology (E) and microstructure (F), hypotype MTQ G61873, Pelorus Island, Australia. G, Oulophyllia levis (Nemenzo, 1959); macromorphology, holotype UP C-412, Cebu, the Philippines (photo by K. S. Luzon). H, I, Oulophyllia bennettae (Veron, Pichon & Wijsman- Best, 1977); micromorphology (H) and microstructure (I), hypotype RMNH 21743, Tukang Besi Islands, Indonesia.