Goniastrea, 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 : 317-320

GENUS GONIASTREA MILNE EDWARDS & HAIME, 1848 A: 495 ( FIG. 14 )

Type species

Astrea retiformis Lamarck, 1816: 265 ; original designation, Milne Edwards & Haime, 1848a, vol. 27: 495.

Original description

‘Multiplication par fissiparité. Murailles compactes et directement soudées entre elles. Cloisons finement denticulées, et portant des palis bien marqués. Columelle peu développée, mince à la partie inférieure des chambres.’ ( Milne Edwards & Haime, 1848a, vol. 27: 495).

Subsequent descriptions

Milne Edwards & Haime, 1849b, vol. 12: 160; d’Orbigny, 1851: 170; Milne Edwards & Haime, 1857, vol. 2: 444; Klunzinger, 1879: 32; Duncan, 1884: 102; Quelch, 1886: 99; Saville Kent, 1893: 163; Ogilvie, 1896: 146–153; Gardiner, 1899: 746; Delage & Hérouard, 1901: 629; Gardiner, 1904: 772; Matthai, 1914: 115, 116; Vaughan, 1918: 113, 114; Vaughan, 1919: 416; Hickson, 1924: 53, 54; Hoffmeister, 1925: 26; Faustino, 1927: 139; Coryell & Ohlsen, 1929: 201; Yabe et al., 1936: 33; Vaughan & Wells, 1943: 167, 168; Alloiteau, 1952: 617; Crossland, 1952: 132, 133; Wells, 1956: F402; Nemenzo, 1959: 97; Chevalier, 1971: 231; Wijsman-Best, 1972: 37; Veron et al., 1977: 79; Scheer & Pillai, 1983: 119; Wood, 1983: 150; Veron, 1986: 478; Chevalier & Beauvais, 1987: 714; Sheppard, 1990: 10; Sheppard & Sheppard, 1991: 130; Veron, 2000, vol. 3: 156, 157.

Diagnosis

Colonial, with intracalicular budding only. Corallites monomorphic and discrete (one to three centres) or uniserial; monticules absent. Walls generally fused, but moderate costate coenosteum (<corallite diameter) present in Goniastrea stelligera . Calice width small to medium (≤ 15 mm), with low to medium relief (≤ 6 mm). Costosepta generally not confluent. Septa in three cycles (24–36 septa). Free septa present, may be regular or irregular. Septa spaced ≥ six septa per 5 mm. Costosepta equal in relative thickness. Columellae trabecular and generally compact (one to three threads), spongy (> three threads) in Goniastrea australensis , <1/4 of calice width, and continuous amongst adjacent corallites. Paliform (uniaxial) lobes well developed, and may be present as septal (multiaxial) lobes. Epitheca well developed and endotheca low−moderate (tabular) ( Fig. 14A, D, G, J ).

Tooth base at midcalice circular. Tooth tip at midcalice irregular; tip orientation perpendicular to septum. Tooth height low to medium (≤ 0.6 mm) and tooth spacing narrow to medium (≤ 1 mm), with> six teeth per septum. Granules scattered on septal face; irregular in shape. Interarea palisade ( Fig. 14B, E, H, K ).

Walls formed by strong abortive septa and partial septotheca; trabeculothecal elements may be present; dominant paratheca in Goniastrea australensis . Thickening deposits fibrous. Costa centre clusters weak; ≤ 0.6 mm between clusters; medial lines weak. Septum centre clusters weak; <0.3 mm between clusters; medial lines weak. Transverse crosses absent. Columella centres clustered ( Fig. 14C, F, I, L ).

Species included

1. Goniastrea retiformis ( Lamarck, 1816: 265) ; holotype: MNHN IK-2010-693 (dry specimen; Fig. 14A ); type locality: ‘les iles Seychelles’ ( Milne Edwards & Haime, 1849b, vol. 12: 161); phylogenetic data: molecular and morphology.

2. Goniastrea australensis ( Milne Edwards & Haime, 1857, vol. 2: 520); holotype: MNHN IK-2010-409 ; type locality: Australia; phylogenetic data: molecular and morphology .

3. Goniastrea columella Crossland, 1948: 191 , pls 8, 10a; holotype: NHMUK 1961.7 .17.46 (dry specimen); type locality: Umpangazi , South Africa; phylogenetic data: none .

4. Goniastrea deformis Veron, 1990: 142 , figs 48– 50, 83; holotype: MTQ G32487 (dry specimen); type locality: Kushimoto, Japan, 4 m depth; molecular only ( Fukami et al., 2008).

5. Goniastrea edwardsi Chevalier, 1971: 240 , pl. 27: fig. 2, pl. 28: figs 6, 7, pl. 29: figs 5, 6; holotype: MNHN IK-2010-654, Goniastrea solida collected by Milne Edwards, and described by Milne Edwards & Haime (1849b, vol. 12: 160, vol. 10, pl. 9: figs 7, 7a; dry specimen; Fig. 14D ); type locality: Seychelles; phylogenetic data: molecular and morphology.

6. Goniastrea favulus ( Dana, 1846: 245, pl. 13: fig. 7); syntype: USNM 66 (dry specimen; Fig. 14G– I ); syntype: YPM IZ 4323 (dry specimen); type locality: Fiji; phylogenetic data: molecular and morphology .

7. Goniastrea minuta Veron, 2000 , vol. 3: 158, figs 1–5 (see also Veron, 2002: 153, figs 283–285; ICZN, 2011: 164); lectotype (designated herein): MTQ G55825 (dry specimen); hypotype: MTQ G60250, figured in Veron (2002: 154, fig. 285; dry specimen); type locality: Milne Bay, Papua New Guinea, 4 m depth; phylogenetic data: none.

8. Goniastrea pectinata ( Ehrenberg, 1834: 320) ; holotype: ZMB Cni 726; type locality: Red Sea; phylogenetic data: molecular and morphology .

9. Goniastrea ramosa Veron, 2000 , vol. 3: 160, figs 1, 2 (see also Veron, 2002: 155, figs 286–288; ICZN, 2011: 164); lectotype (designated herein): MTQ G55803 (dry specimen); type locality: Flores, Indonesia, 1 m depth; phylogenetic data: none.

10. Goniastrea stelligera ( Dana, 1846: 216, pl. 10: fig. 9); syntype: USNM 55 (dry specimen; Fig. 14J– L ); type locality: Fiji; phylogenetic data: molecular and morphology .

11. Goniastrea thecata Veron, DeVantier & Turak, 2000 ( Veron, 2000, vol. 3: 169, fig. 5; see also Veron, 2002: 157, figs 289–291; ICZN, 2011: 164); lectotype (designated herein): MTQ G55837 (dry specimen); type locality: northern Red Sea coast of Saudi Arabia, 1 m depth; phylogenetic data: none.

Taxonomic remarks

Goniastrea Milne Edwards & Haime, 1848a , vol. 27: 495, accumulated new species gradually since the description of its type in the genus Astrea Lamarck, 1816 , until as recently as the year 2000, in which three species were added ( Veron, 2000). The genus was thought to have affinities with Favia and Favites ( Chevalier, 1971; Veron et al., 1977), but molecular and morphological phylogenies have consistently placed the majority of its species within a clade that also includes Merulina and/or Scapophyllia (Fig. 2; Huang et al., 2011; Arrigoni et al., 2012).

Both data types support the sister relationship between the type species of Goniastrea , Goniastrea retiformis , and Astrea (Orbicella) stelligera Dana, 1846: 216 , the latter conventionally regarded as an Indo-Pacific Favia ( Veron, 2000, vol. 3: 102). This lends further support to the reasoning that coenosteum amount, moderate in this species but absent in Goniastrea , is an extremely homoplastic character, experiencing multiple changes near the tips of the tree. Astrea stelligera is hereby synonymized as Goniastrea stelligera .

Goniastrea australensis and Goniastrea deformis are not nested within other Goniastrea spp. but have been recovered near the main Goniastrea clade to varying degrees (Fig. 2; Fukami et al., 2008; Huang et al., 2011; Arrigoni et al., 2012). Overall, the polyphyly of this genus ensures that the three remaining species – yet to be examined in a phylogenetic context – cannot be unequivocally placed (but see Huang, 2012). Despite forming at least two Goniastrea subclades that may not be sister groups, we consider it premature to make formal changes to these species until certainty of their positions increases appreciably.

On the contrary, Goniastrea aspera Verrill, 1866: 32 , and Favia palauensis Yabe & Sugiyama, 1936: 30 , clearly belong in a separate taxon with affinities to Dipsastraea (molecular; Huang et al., 2011; Arrigoni et al., 2012; Fig. 2A) and Trachyphyllia (morphology; Fig. 2B). Accordingly, we place them in Coelastrea Verrill, 1866: 32 .

Goniastrea is widely distributed on reefs of the Indo- Pacific, recorded throughout most of French Polynesia and the Pitcairn Islands in the Southern Hemisphere ( Glynn et al., 2007), but absent eastwards from Hawai’i in the north.

Morphological remarks

No apomorphies have been identified for Goniastrea , mainly because of the recovery of Goniastrea australensis outside of the Goniastrea clade.

Whereas the molecular trees generally show that Merulina and Scapophyllia are nested within the Goniastrea clade, morphological evidence indicates a sister relationship. It should be noted that they may not be as distinct as previously thought. In particular, the lack of apomorphies for Goniastrea amongst the suite of characters tested suggests that these genera share numerous traits, including all subcorallite characters analysed here. Nevertheless, Goniastrea differs from Merulina and Scapophyllia in having mostly discrete corallites, costosepta that are not confluent across walls, well-developed epitheca and low−moderate (tabular) endotheca.

Goniastrea is also commonly confused with Favites spp. that have fused walls, as they do share most macromorphological characters. However, the former do not generally possess confluent costosepta, and have fewer vesicular endotheca as well as internal lobes that are multiaxial (i.e. septal lobes). The more striking disparities are only observed via thin sections that show the presence of abortive septa and partial trabeculotheca only in Goniastrea , and by contrast, paratheca, strong costa centre clusters, and transverse crosses in Favites .

Figures

Figure 14. Goniastrea Milne Edwards & Haime, 1848a, generally has discrete corallites, small to medium (≤ 15 mm) calices, equally thick costosepta, and well-developed paliform (uniaxial) and/or septal (multiaxial) lobes. Septal teeth are often low (<0.3 mm) and narrowly spaced (<0.3 mm). Walls formed by strong abortive septa and partial septotheca; trabeculothecal elements may be present. A–C, Goniastrea retiformis (Lamarck, 1816), type species of Goniastrea; macromorphology, holotype MNHN IK-2010-693, unknown locality (A); micromorphology (scanning electron microscopy; B) and microstructure (transverse thin section; C), hypotype USNM 1013047 (FA1030), Saipan, Mariana Islands. D–F, Goniastrea edwardsi Chevalier, 1971; macromorphology, holotype MNHN IK-2010-654, Seychelles (D); micromorphology (E) and microstructure (F), hypotype RMNH 11194, Lizard Island, Australia. G–I, Goniastrea favulus (Dana, 1846); macromorphology (G), micromorphology (H), and microstructure (I), syntype USNM 66, Fiji. J–L, Goniastrea stelligera (Dana, 1846); macromorphology (J), micromorphology (K), and microstructure (L), syntype USNM 55, Fiji.