Milne Edwards and Haime, 1848, p. 495
Acanthastrea spinosa Milne Edwards and Haime, 1848, p. 495; Original Designation Milne Edwards and Haime, 1848: 495
Type Specimen: Holotype; MNHN IK-2010-599; Verified; Dry Preserved
Type Locality: Habite Tongatabou (Recent)
See also Milne Edwards and Haime, 1849c, p. 145-146. The holotype is Quoy and Gaimard's (1833, p. 210) specimen of "Astrea dipsacea var.". Acanthastrea spinosa was later synonymized with Astraea echinata Dana 1846, p. 209, holotype= USNM 000025; see Vaughan and Wells, 1943, p. 194.
Colonial; submassive or massive. Budding intracalicular and extracalicular. Corallites monomorphic; mainly discrete. Monticules absent. Coenosteum spinose; limited (includes double wall), moderate (< corallite diameter) amount, or colonies may be phaceloid or partly flabello-meandroid. Calice width medium to large (≥ 4 mm), with medium to high relief (≥ 3 mm). Costosepta mostly confluent. Septa in three cycles (24–36 septa). Free septa irregular. Septa spaced < six septa per 5 mm. Costosepta unequal in relative thickness. Columellae trabecular and spongy (> three threads), < 1/4 of calice width, and discontinuous among adjacent corallites with lamellar linkage. Internal lobes usually absent. Epitheca reduced. Endotheca low-moderate (tabular). Tooth base at midcalice elliptical-parallel. Tooth tip orientation parallel. Tooth height usually medium (0.3–0.6 mm). Tooth spacing medium to wide (≥ 0.3 mm), with ≤ six teeth per septum. Tooth shape unequal between first and third order septa. Tooth size equal between wall and septum. Granules scattered on septal face; weak (rounded). Interarea smooth. Walls formed by dominant paratheca and partial septotheca. Thickening deposits in concentric rings with extensive stereome. Costa centre clusters strong; > 0.6 mm between clusters; medial lines weak. Septum centre clusters may be strong; > 0.5 mm between clusters; medial lines weak.
'Se sépare de toutes les autres Astrées par ses cloisons très-échinulées dont les épines les plus fortes sont les plus extérieures.' (Milne Edwards and Haime, 1848a, vol. 27: 495)
The genus forms a paraphyly on the morphological phylogeny. On the molecular tree, Acanthastrea possesses several symplesiomorphies, including extracalicular budding, discrete corallites, columellae < 1/4 of calice width, reduced epitheca, parallel tooth tip at midcalice, strong costa centre clusters, weak costa medial lines, > 0.5 mm between septum centre clusters. These traits distinguish Acanthastrea from its sister clade of Echinophyllia + Oxypora. Excluding A. pachysepta, the genus is moderately supported on the morphology tree (bootstrap support of 68), with limited/moderate coenosteum amount and strong septum centre clusters as synapomorphies. Several characters separate Acanthastrea from taxa previously associated with the genus that are in subclades A (Micromussa), B (Homophyllia), C (Sclerophyllia) and I (Lobophyllia), including septa spacing, epitheca and endotheca development, number of teeth per septum, S1/S3 tooth shape and wall/septum tooth size. Acanthastrea has historically been confused with the merulinid genus Favites Link, 1807: 162, as they are superficially alike and the inner edge of the septum possesses similar teeth (Chevalier, 1975). When Matthai (1914) synonymised Favites with Favia Oken, 1815: 67, the Acanthastrea species (i.e. F. hirsuta and F. hemprichii) were also transferred into Favia, though these actions were almost immediately reversed as Vaughan (1918) revived both Favites and Acanthastrea. The latter is easily distinguished from Favites by its sparser septa (three cycles; 24–36 septa; < six septa per 5 mm), lamellar linkage between columellae, absence of paliform lobes, reduced epitheca and endotheca, less numerous septal teeth that are parallel to the septa at midcalice, smooth interarea, thickening deposits in concentric rings with extensive stereome, wider separation between centre clusters, and the lack of transverse crosses.
The genus was first described to contain four monocentric species (i.e. 'Astrées'; Milne Edwards and Haime, 1848a, vol. 27: 495) that have especially spinose wall septa—Acanthastrea hirsuta Milne Edwards and Haime, 1849b, vol. 12: 145, Acanthastrea spinosa Milne Edwards and Haime, 1848a, vol. 27: 495, Acanthastrea brevis Milne Edwards and Haime, 1849b, vol. 12: 146, and Acanthastrea grandis Milne Edwards and Haime, 1849b, vol. 12: 146. These species have been synonymised as Acanthastrea echinata (Dana, 1846: 229) (Chevalier, 1975; Veron and Pichon, 1980). It should be noted that the A. spinosa specimen used by Milne Edwards and Haime, 1848a, vol 27: 495, to establish the genus (MNHN IK-2010-599) should still be considered the type of Acanthastrea. By the time of Veron (2000), 12 Acanthastrea species were recognised as valid, including five described by Veron (1990, 2000) and Veron and Pichon (1982). Molecular phylogenetic analyses by Fukami et al. (2008) then showed that the genus was polyphyletic, with representatives in clades XVIII, clustering with Micromussa amakusensis (Veron, 1990: 137), and XX (sensu Fukami et al., 2008). Kitahara et al. (2010) obtained a similar result, but extensive sampling by Arrigoni et al. (2014c) further showed that Acanthastrea is distributed among four major subclades (B, C, E and I, sensu Arrigoni et al., 2014c). Arrigoni et al. (2015) then swiftly moved A. maxima Sheppard and Salm, 1988: 276, into the revived Sclerophyllia Klunzinger, 1879: 4. Finally, Arrigoni et al. (2016a) synonymised A. hillae Wells, 1955, under A. bowerbanki Milne Edwards and Haime, 1857, and moved the species into Homophyllia. Acanthastrea lordhowensis Veron and Pichon, 1982, was also transferred into Micromussa, while Micromussa minuta (Moll and Best, 1984) was moved into Acanthastrea based on detailed examination of the holotype (Arrigoni et al., 2016a). Our molecular and morphological trees support these changes, and also the further transfers of Acanthastrea ishigakiensis Veron, 1990: 132, into Lobophyllia, and Acanthastrea regularis Veron, 2000, vol. 3: 16, into Micromussa. Arrigoni et al. (2014c) suggested that A. faviaformis Veron, 2000, vol. 3: 24, should be transferred into the merulinid genus Dipsastraea de Blainville, 1830, and our examination of the lectotype (designated herein) shows that its macromorphological characters are scored identically with Dipsastraea spp. (Appendix S2). Here we formally carry out the genus reassignment—Dipsastraea faviaformis (Veron, 2000), new combination. The molecular phylogeny here groups Lobophyllia pachysepta Chevalier, 1975: 269, and the remaining Acanthastrea species together in subclade E, although they form a paraphyly on the morphological phylogeny owing to the disparately large corallites and phaceloid/flabello-meandroid colonies of L. pachysepta. Based on the molecular tree and subcorallite characters that are nearly identical between this rogue species and Acanthastrea—differing only in tooth spacing and distinctiveness of septum centre clusters—we move L. pachysepta into the present genus. The resulting classification thus comprises seven Acanthastrea species. Acanthastrea is widely distributed on the reefs of Indo-Pacific, present from the Red Sea and East Africa to as far east as the Marshall Islands in the Northern Hemisphere (Veron, 2000) and Gambier Islands in the Southern Hemisphere (Glynn et al., 2007).
Source: Paleobiology Database (18 August 2011); GBIF (18 August 2011).
- South America; Eocene
- Central Europe, Eastern Europe; Pliocene - Pleistocene
- Indian Ocean; Recent
- Western Pacific; Recent
- Central Pacific; Recent
- Eastern Pacific; Recent
This page has been in preparation since 04-Jun-2007 16:56
This version was contributed by Danwei Huang on 29-Jan-2016 13:43.
Page authors are: Ann Budd Danwei Huang. Please contact the editor if you would like to contribute to the diagnosis of this taxon.
The editor is: Ann Budd