Hydnophora, FISCHER VON WALDHEIM, 1807: 295

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 : 320-322

GENUS HYDNOPHORA FISCHER VON WALDHEIM, 1807: 295 ( FIG. 15 )

Synonyms

Hydnophorella Delage & Hérouard, 1901: 628 , fig. 876 (type species: Hydnophora contignatio Klunzinger, 1879: 23 , pl. 3: figs 2, 3, pl. 9: fig. 12a, b, c = Madrepora exesa Pallas, 1766: 290 ; original designation, Delage & Hérouard, 1901: 628); Monticularia Lamarck, 1816: 248 (type species: Monticularia folium Lamarck, 1816: 250 = Madrepora exesa Pallas, 1766: 290 ; original designation, Lamarck, 1816: 250); Monticulina Saville Kent, 1893: 169 (type species Hydnophora rigida Saville Kent, 1893: 168 , chromo pl. 7: fig. 7; original designation, Saville Kent, 1893: 169).

Type species

Hydnophora demidovii Fischer von Waldheim, 1807: 295 , pl. 4 = Madrepora exesa Pallas, 1766: 290 (see Milne Edwards & Haime, 1857, vol. 2: 420; Vaughan, 1918: 121; Matthai, 1928: 140; Chevalier, 1975: 175); original designation, Fischer von Waldheim, 1807: 295.

Original description

‘Polypier pierreux, crustacé, en masse glomérulée ou en expansions lobées, subfoliacées, ayant sa surface supérieure parsemée d’étoiles lamelleuses, à centre solide, pyramidal, et plus ou moins élevé.’ ( Fischer von Waldheim, 1807: 295).

Subsequent descriptions

Milne Edwards & Haime, 1848a, vol. 27: 493; Milne Edwards & Haime, 1849a, vol. 11: 299, 300; d’Orbigny, 1851: 168; Milne Edwards & Haime, 1857, vol. 2: 418, 419; Klunzinger, 1879: 20; Quenstedt, 1881: 1013; Duncan, 1884: 97; Quelch, 1886: 95; Saville Kent, 1893: 168, 169; Gardiner, 1899: 744; Delage & Hérouard, 1901: 702; Gardiner, 1904: 764; Vaughan, 1918: 121; Hoffmeister, 1925: 29, 30; Faustino, 1927: 148, 149; Matthai, 1928: 136, 137; Coryell & Ohlsen, 1929: 202, 203; Yabe et al., 1936: 39; Vaughan & Wells, 1943: 169, 170; Alloiteau, 1952: 618; Wells, 1956: F402, F403; Nemenzo, 1959: 102; Wijsman-Best, 1972: 51; Chevalier, 1975: 167; Veron et al., 1977: 124; Scheer & Pillai, 1983: 127; Wood, 1983: 158; Veron, 1986: 428; Chevalier & Beauvais, 1987: 717; Veron & Hodgson, 1989: 268; Sheppard, 1990: 12; Best & Suharsono, 1991: 334; Sheppard & Sheppard, 1991: 117; Bosellini, 1999: 222; Veron, 2000, vol. 2: 364.

Diagnosis (apomorphies in italics)

Colonial, with intracalicular budding only. Corallites monomorphic and uniserial; monticules present. Walls fused. Calice width small to medium (≤ 15 mm), with low to medium relief (≤ 6 mm). Costosepta not confluent. Septa in <three cycles (<24 septa). Free septa absent. Septa spaced six to 11 septa per 5 mm. Costosepta equal in relative thickness. Columellae trabecular but compact (one to three threads), <1/4 of calice width, and continuous amongst adjacent corallites. Paliform (uniaxial) lobes absent. Epitheca reduced and endotheca sparse ( Fig. 15A, D, G ).

Tooth base at midcalice circular. Tooth tip at midcalice irregular; tip orientation perpendicular to septum. Tooth height low (<0.3 mm) and tooth spacing narrow (<0.3 mm), with> six teeth per septum. Granules aligned on septal face, perpendicular to septal margin; irregular in shape. Interarea palisade ( Fig. 15B, E, H ).

Walls formed by dominant trabeculotheca and partial septotheca; abortive septa absent. Thickening deposits fibrous. Costa centre clusters weak; <0.3 mm between clusters; medial lines strong. Septum centre clusters weak; <0.3 mm between clusters; medial lines strong. Transverse crosses absent. Columella centres aligned ( Fig. 15C, F, I ).

Species included

1. Hydnophora exesa ( Pallas, 1766: 290) ; holotype: lost ( Chevalier, 1975: 176); neotype (designated herein): UP P1 L02157 (dry specimen; Fig. 15A ); type locality: Talim Bay, Batangas, the Philippines, 2.5 m depth (‘Oceanus Indicus’; Pallas, 1766: 291); phylogenetic data: molecular and morphology.

2. Hydnophora bonsai Veron, 1990: 139 , figs 46, 47; holotype: MTQ G32486 (dry specimen); type locality: Kushimoto , Japan, 4 m depth; phylogenetic data: none .

3. Hydnophora grandis Gardiner, 1904: 764 , pl. 60: fig. 11; syntypes: NHMUK 1928.4.18.227 ( Fig. 15D ), 1928.5.2.1 (two dry specimens); type locality: south Nilandu and Haddumati, Maldives (see also Matthai, 1928: 153); phylogenetic data: molecular ( Fukami et al., 2008) and morphology.

4. Hydnophora microconos ( Lamarck, 1816: 251) ; holotype: MNHN IK-2010-477 (dry specimen); type locality: ‘lOcéan des Grandes-Indes’ ( Lamarck, 1836: 393); phylogenetic data: molecular and morphology.

5. Hydnophora pilosa Veron, 1985: 176 , figs 26–28; holotype: WAM 174-84 (also WAM Z919; Griffith & Fromont, 1998: 235) (dry specimen); paratypes: WAM 175-84, 176-84 (also WAM Z920, Z921; Griffith & Fromont, 1998: 235) (two dry specimens); type locality: Elizabeth Reef, eastern Australia, 6 m depth; phylogenetic data: molecular and partial morphology.

6. Hydnophora rigida ( Dana, 1846: 276, pl. 17: figs 1, 1a–c); syntype: USNM 148 (dry specimen; Fig. 15G, I ); type locality: Fiji; phylogenetic data: morphology only .

Taxonomic remarks

Hydnophora Fischer von Waldheim, 1807: 295 , is a distinct genus whose monophyly (subclade H) has been well supported by molecular data ( Huang et al., 2011; Huang, 2012). Prior to Veron’s (1986: 428, 2000, vol. 2: 364) placement of Hydnophora within Merulinidae , it was more often associated with Faviidae sensu Wells, 1956 : F402 (see Vaughan & Wells, 1943: 169; Chevalier, 1975: 167; Veron et al., 1977: 124). Molecular phylogenies show that it is most closely related to Favites , Leptoria , and Platygyra ( Huang et al., 2011) , or Astrea curta and Favites russelli ( Arrigoni et al., 2012) , and relatively distinct from Merulina and Scapophyllia , the other Merulinidae taxa before the revision of Budd et al. (2012).

The genus is relatively well sampled. Only Hydnophora bonsai , a Japanese endemic ( Veron, 1990: 141), has not been investigated in a phylogenetic context.

Hydnophora is widely distributed on reefs of the Indo- Pacific, present as far east as the Austral Islands in the Southern Hemisphere ( Glynn et al., 2007), but absent eastwards from Hawai’i in the north.

Morphological remarks

On the morphology tree, Hydnophora is supported by a high bootstrap value (95) and decay index (4), and is sister to the clade formed by Australogyra , Leptoria , and Platygyra . It is distinguished as the only scleractinian taxon to possess monticules. Other synapomorphies include the reduced epitheca (likelihood of 1.0 based on the Mk1 model), sparse endotheca (likelihood 1.0), and lack of free septa (likelihood 1.0), all of which make the genus easily separable from its close relatives. Note, however, that the type material of Hydnophora grandis has relatively vesicular endotheca, although other specimens examined possess the generic state.

Figures

Figure 15. Hydnophora Fischer von Waldheim, 1807, has uniserial corallites, monticules and fused walls, septa in <three cycles (<24 septa), no free septa, compact columellae, reduced epitheca, and generally sparse endotheca. Septal teeth are low (<0.3 mm) and narrowly spaced (<0.3 mm); irregularly shaped granules aligned on septal face. Walls formed by dominant trabeculotheca and partial septotheca, with strong costal and septal medial lines, and aligned columella centres. A–C, Hydnophora exesa (Pallas, 1766: 290), type species of Hydnophora; macromorphology, neotype (designated herein) UP P1L02157, Batangas, the Philippines (A); micromorphology (scanning electron microscopy; B) and microstructure (transverse thin section; C), hypotype USNM 91183, Lord Howe Island, Australia. D–F, Hydnophora grandis Gardiner, 1904; macromorphology, syntype NHMUK 1928.4.18.227, south Nilandu, Maldives (D); micromorphology (E) and microstructure (F), hypotype UF 2063 (FA1084), Palau. G–I, Hydnophora rigida (Dana, 1846); macromorphology (G) and microstructure (I), syntype USNM 148, Fiji; micromorphology, syntype of Merulina laxa Dana, 1846 USNM 4501, Sulu Sea (H).