A phylogeny of the family Poritidae (Cnidaria, Scleractinia) based on molecular and morphological analyses.

The family Poritidae formerly included 6 genera: Alveopora, Goniopora, Machadoporites, Porites, Poritipora, and Stylaraea. Morphologically, the genera can be differentiated based on the number of tentacles, the number of septa and their arrangement, the length of the polyp column, and the diameter of the corallites. However, the phylogenetic relationships within and between the genera are unknown or contentious. On the one hand, Alveopora has been transferred to the Acroporidae recently because it was shown to be more closely related to this family than to the Poritidae by previous molecular studies. On the other hand, Goniopora is morphologically similar to 2 recently described genera, Machadoporites and Poritipora, particularly with regard to the number of septa (approximately 24), but they have not yet been investigated at the molecular level. In this study, we analyzed 93 samples from all 5 poritid genera and Alveopora using 2 genetic markers (the barcoding region of the mitochondrial COI and the ITS region of the nuclear rDNA) to investigate their phylogenetic relationships and to revise their taxonomy. The reconstructed molecular trees confirmed that Alveopora is genetically distant from all poritid genera but closely related to the family Acroporidae, whereas the other genera are genetically closely related. The molecular trees also revealed that Machadoporites and Poritipora were indistinguishable from Goniopora. However, Goniopora stutchburyi was genetically isolated from the other congeneric species and formed a sister group to Goniopora together with Porites and Stylaraea, thus suggesting that 24 septa could be an ancestral feature in the Poritidae. Based on these data, we move G. stutchburyi into a new genus, Bernardpora gen. nov., whereas Machadoporites and Poritipora are merged with Goniopora.

Introduction

The family Poritidae Gray, 1842 is distributed throughout the tropics [1] and includes over 140 nominal species [2], some of which are among the major coral reef framework builders. The family formerly included 6 extant genera (currently Alveopora is not included), 3 of which are species-rich [1]—Porites Link, 1807 (73 species), Goniopora de Blainville, 1830 (31 spp.), and Alveopora de Blainville, 1830 (18 spp.)—and 3 are monospecific—Stylaraea Milne Edwards & Haime, 1851, Poritipora Veron, 2000, and Machadoporites Nemésio, 2005. These last 3 are rare or restricted to peculiar environmental conditions or have a limited geographic distribution. Conversely, the 3 major genera are common throughout the Indo-Pacific, with Porites extending into the Atlantic, from tropical to temperate regions. The biological, ecological and biometeorological studies such as climate change using Porites are well known [3]–[7], and this genus has been studied extensively at the molecular level in comparison with other coral genera [8]–[10] although it is still very difficult to divide Porites into discrete species in some cases (e.g., P. lutea and P. lobata)[9] due to the tiny but highly variable morphological characters used in the classification. In contrast, there are very few ecological and molecular studies of other Poritidae [11], [12], with the exception of our recent work showing the phylogenetic relationships of several species of Goniopora [13].

There has been some dispute over the classification of genera in the Poritidae since the revision by Dana [14]. In particular, the position of Alveopora has been contentious [15]. Vaughan and Wells [16] reinstated Alveopora in the Poritidae because of its similarity to Goniopora in ecology and polyp behavior, although in listing the skeletal characteristics of the genus, Wells [17] qualified most as “except in Alveopora”. Alveopora may be confused with Goniopora in the field because the polyps of both genera have very long columns, a character not shared with other genera, and these are usually elongated, obscuring the skeleton. As Veron and Pichon [15] noted, Goniopora polyps have 24 tentacles whereas Alveopora polyps have 12 tentacles. Moreover, they state that “no east Australian Alveopora shows any sign of having either of the patterns of septal fusion found in Porites or Goniopora.” In support of this argument, recent molecular studies have indicated that Alveopora is genetically distant from Porites and Goniopora [18], [19], although only a few specimens and species from each genus were analyzed in these studies. Based only on the evidence from these published genetic works, Alveopora was transferred from the Poritidae to the Acroporidae Verrill, 1902 by Dai and Horng [20], albeit without any formal diagnosis or discussion. Recently the characters of Alveopora have been discussed in relation to the Acroporidae [21], [22].

Goniopora is easily distinguishable from other genera in the Poritidae, with 3 septal cycles and 24 septa (vs. 2 septal cycles and 12 septa for Porites, Alveopora, and Stylaraea) and larger corallites [15]. Machadoporites has 15–22 septa and hence fewer than Goniopora [23]. Poritipora skeletal morphology is quite similar to that of Goniopora due to the presence of 24 septa, but the former has smaller corallites and only 2 septal cycles [24]. Stylaraea is the only monospecific poritid genus to have been studied since its description. One ecological study [25] and a few morphological studies [26] have been reported for Stylaraea. Stylaraea punctata is possibly the smallest colonial zooxanthellate scleractinian coral and has been reported as a brooder [25]. This genus superficially resembles Porites, but is distinguished from it by reduced septation without the Porites pattern of fusion (e.g. septal triplet), and the absence of pali, although its phylogenetic position in the Poritidae has not been studied.

Recent molecular phylogenetic analyses of scleractinian corals [19], [27]–[31] revealed that molecular-based phylogenetic relationships sometimes conflict with traditional macromorphology-based taxonomy. This indicates that the current, common identifying characters within a family or genus of scleractinian corals do not always reflect their phylogenetic relationships. One such inconsistency is seen in the relationship between Atlantic and Indo-Pacific Faviidae Gregory, 1900 [27] (but see [32] for the taxonomic revision). Despite such conflicts, there are also many cases in which molecular data are consistent with traditional taxonomy. Moreover, some morphological characters previously not considered key characters have been found to be effective as diagnostics for the phylogenetic relationships in several cases [32]–[34]. Overall, most molecular studies conclude that molecular analysis is useful in discerning the relationships of species or genera and inferring the phylogeny. Forsman et al. [9] investigated the molecular-based phylogenetic relationships among species of Porites, using mainly the entire internal transcribed spacer region (ITS) of the nuclear ribosomal DNA. Their results showed that most species of Porites were clearly distinguishable genetically, highlighting the usefulness of ITS markers in inferring relationships in Porites at the species level.

In this study, we assess the relationship of all 5 genera in the Poritidae with Alveopora to revise the taxonomy, and infer the morphological changes in the evolutional lineage in this family, using both molecular and morphological analysis. Also to assess phylogenetic variation in the regional and species differences, the present study examines a large number of specimens collected with broad geographic ranges from mainly Japan water to the Indian Ocean, covering most of common species and some uncommon and rare species, together with the genetic data of Porites spp. from Forsman et al. [9].

Materials and Methods

Collection

Most specimens (approximately 10 cm3 in size) were collected from 17 sites in Japan (Fig. 1). Additionally some samples were collected from Malaysia, and western Indian Ocean (Table 1). All Japanese sampling (AK, AM, AO, IK, IR, IS, KK, KS, MI, MO, OT, OU, SO, SR, SS, TN, TR; see Fig. 1) was performed in the frame of research projects by Japanese Society for Coral Taxonomy or by associate prof. H. Fukami at University of Miyazaki with sampling permission from each local government in Japan. Malaysia (PEN; see Fig. 1) sampling has taken place by local staffs in non-marine protected area, Songsong Island, under the permission of the research project by prof. Zulfigar Yasin and prof. Aileen Tan at Universiti Sains Malaysia. All western Indian Ocean sampling was also performed in the frame of research projects for which a sampling permission was delivered by local authorities and samples were shipped with CITES permits. AD, BA, BU, DJ, and MU are all sites in Yemen (Fig. 1). There, sampling has taken place in several missions and regular sampling permits were issued by Yemen Environmental Protection Agency (EPA) in Sana'a. Moreover, EPA staff supervised the activities in the field at all times. MY is Mayotte Island (Fig. 1). Sampling permits there were issued by the Direction de l'Agriculture et de la Foret de Mayotte, Service Environnement et Foret and by the Maritime Affairs Office. DJ are samples from Djibouti (Fig. 1) taken during the Tara Oceans expedition and the sampling permits were delivered by the Aménagement du Territoire et de l'Environnement de Djibouti. Photos of each specimen were taken in the field (particularly for living polyps) and the depth and habitat were recorded. After collection, a small piece of each specimen was removed for use in DNA extraction (see below), and the remaining sample was bleached to investigate the skeletal morphology for species identification.

Figure 1

Map of sampling locations for this study.

A: Indian and Pacific Ocean, B: southern Red Sea, Gulf of Tadjoura and Gulf of Aden; C–E: main island of Japan and Ryukyu archipelago. AD: Aden, Yemen, AK: Akajima Island, Japan, AM: Amakusa, Japan, AO: Amami-Oshima, Japan, BA: Bir Ali, Yemen, BU: Al Mukallah, Yemen, DJ: Djibouti, IK: Iki Island, Japan, IR: Iriomote Island or Hatoma Island, Japan, IS: Ishigaki Island or Taketomi Island, Japan, KA: Kamaran Islands, Yemen, KK: Kikai Island, Japan KS: Kushimoto, Japan, MI: Miyako Island, Japan, MY: Mayotte Island, France, OT: Ootuki, Japan, OU: Oura bay, Japan, PEN: Song song Island, Malaysia, SO: Suou-Oshima, Japan, SR: Shirahama, Japan, SS: Sesoko Island, Japan, TN: Tanegashima Island, Japan, TR: Nakanoshima Island, Japan

Table 1

List of samples examined in this study and the accession numbers of DNA sequences.

Family	Species	DNA sample ID	specimen ID	locality	Country	COI (accession No.)	ITS (accession No.)
Acroporidae	Montipora sp.	SR127	MUFS YFK73	Shirahama	Japan	AB907075	-
Acroporidae	Astreopora sp.1	AO29	MUFS YFK444	Amami-Oshima	Japan	AB907076	-
Acroporidae	Astreopora sp.1	AO109	MUFS YFK485	Amami-Oshima	Japan	AB907077	-
Acroporidae	Astreopora sp.2	AO107	MUFS YFK484	Amami-Oshima	Japan	AB907078	-
Acroporidae	Alveopora allingi	AO125	MUFS YFK504	Amami-Oshima	Japan	AB907079	-
Acroporidae	Alveopora allingi	IR47	MUFS YFK1060	Iriomote	Japan	AB907080	-
Acroporidae	Alveopora catalai	AO117	MUFS YFK507	Amami-Oshima	Japan	AB907081	-
Acroporidae	Alveopora catalai	IR21	MUFS YFK971	Iriomote	Japan	AB907082	-
Acroporidae	Alveopora excelsa	KS5	MUFS YFK100	Kushimoto	Japan	AB907083	-
Acroporidae	Alveopora excelsa	OT26	MUFS YFK303	Otsuki	Japan	AB907084	-
Acroporidae	Alveopora excelsa	AM2	MUFS YFK365	Amakusa	Japan	AB907085	-
Acroporidae	Alveopora japonica	SO19	MUFS YFK1112	Suou-Oshima	Japan	AB907086	-
Acroporidae	Alveopora japonica	IK26	MUFS YFK226	Iki	Japan	AB907087	-
Acroporidae	Alveopora japonica	SR120	MUFS YFK66	Shirahama	Japan	AB907088	-
Acroporidae	Alveopora japonica	AM7	MUFS YFK366	Amakusa	Japan	AB907089	-
Acroporidae	Alveopora sp.	TN49	SMBL Cni10611	Tanegashima	Japan	AB907090	-
Acroporidae	Alveopora sp.	TN100	MUFS YFK1035	Tanegashima	Japan	AB907091	-
Acroporidae	Alveopora spongiosa	AO126	MUFS YFK510	Amami-Oshima	Japan	AB907092	-
Acroporidae	Alveopora spongiosa	SS15	MUFS YFK218	Sesoko	Japan	AB907093	-
Acroporidae	Alveopora spongiosa	IR145	MUFS HY11-40	Iriomote	Japan	AB907094	-
Acroporidae	Alveopora tizardi	SR50	MUFS YFK326	Shirahama	Japan	AB907095	-
Acroporidae	Alveopora tizardi	SR115	MUFS YFK58	Shirahama	Japan	AB907096	-
Acroporidae	Alveopora verrilliana	TR80	MUFS YFK689	Nakanoshima	Japan	AB907097	-
Acroporidae	Alveopora verrilliana	IS38	MUFS YFK943	Taketomi	Japan	AB907098	-
Dendrophylliidae	Turbinaria peltata	SR5	MUFS YFK126	Shirahama	Japan	AB907099	-
Dendrophylliidae	Turbinaria peltata	SR143	MUFS YFK89	Shirahama	Japan	AB907100	-
Dendrophylliidae	Turbinaria peltata	OT3	MUFS YFK279	Otsuki	Japan	AB907101	-
Poritidae	Goniopora albiconus	PEN1	MSL/USM/SS001	Songsong	Malaysia	-	AB906942
Poritidae	Goniopora albiconus	PEN9	MSL/USM/SS009	Songsong	Malaysia	-	AB906943
Poritidae	Goniopora albiconus	BA002	UNIMIB BA002	Bir Ali	Yemen	AB907026	AB906944
Poritidae	Goniopora albiconus	DJ074	UNIMIB DJ074	Oblal W	Djibouti	AB907027	AB906945
Poritidae	Goniopora burgosi	OT6	MUFS YFK286	Otsuki	Japan	AB907028	AB906946
Poritidae	Goniopora cf. cellulosa	TN29	MUFS YFK248	Tanegashima	Japan	AB907029	AB906947-51
Poritidae	Goniopora cf. cellulosa	TN54	SMBL Cni10573	Tanegashima	Japan	AB907030	AB906952
Poritidae	Goniopora ciliatus	BA076	UNIMIB BA076	Bir Ali	Yemen	-	AB906953
Poritidae	Goniopora columna	IS1	MUFS YFK351	Ishigaki	Japan	AB907031	AB906954
Poritidae	Goniopora columna	IS3	MUFS YFK353	Ishigaki	Japan	AB907032	AB748660*
Poritidae	Goniopora djiboutiensis	AK18	MUFS YFK163	Akajima Island	Japan	AB907033	AB906955-6
Poritidae	Goniopora cf. fruticosa	TN12	MUFS YFK263	Tanegashima	Japan	-	AB906957
Poritidae	Goniopora cf. fruticosa	TR1	MUFS YFK643	Nakanoshima	Japan	-	AB906958
Poritidae	Goniopora cf. fruticosa	TR4	MUFS YFK641	Nakanoshima	Japan	AB907034	AB906959
Poritidae	Goniopora cf. fruticosa	AO28	MUFS YFK443	Amami-Oshima	Japan	AB907035	AB906960
Poritidae	Goniopora cf. fruticosa	AO87	MUFS YFK458	Amami-Oshima	Japan	-	AB906961
Poritidae	Goniopora lobata	KK17	MUFS YFK813	Kikai	Japan	AB907036	AB906962
Poritidae	Goniopora minor	AO135	MUFS YFK513	Amami-Oshima	Japan	AB907037	AB906963
Poritidae	Goniopora minor	OU56	MUFS YFK773	Oura bay	Japan	AB907038	AB906964
Poritidae	Goniopora minor	MI6	MUFS KSMH20	Miyako	Japan	AB907039	AB906965
Poritidae	Goniopora minor	IR34	MUFS YFK988	Iriomote	Japan	-	AB906966
Poritidae	Goniopora minor	MY029	UNIMIB MY029	Ile Vert	Mayotte, France	-	AB906967
Poritidae	Goniopora norfolkensis	KK53	MUFS YFK843	Kikai	Japan	-	AB906968
Poritidae	Goniopora norfolkensis	AK2	MUFS YFK159	Akajima Island	Japan	AB907040	AB906969
Poritidae	Goniopora norfolkensis	IS7	MUFS YFK399	Ishigaki	Japan	AB907041	AB906970
Poritidae	Goniopora cf. norfolkensis	AK8	MUFS YFK165	Akajima Island	Japan	AB907042	AB906971
Poritidae	Poritipora paliformis	IS27	MUFS YFK940	Taketomi	Japan	AB907043	AB906972
Poritidae	Poritipora paliformis	IS48	MUFS YFK959	Taketomi	Japan	AB907044	AB906973
Poritidae	Goniopora cf. pendulus	PEN29	MSL/USM/SS029	Songsong	Malaysia	-	AB906974
Poritidae	Goniopora somaliensis	TR85	MUFS YFK690	Nakanoshima	Japan	AB907045	AB906975
Poritidae	Goniopora somaliensis	KK50	MUFS YFK841	Kikai	Japan	AB907046	AB906976
Poritidae	Goniopora somaliensis	OU29	MUFS YFK764	Oura bay	Japan	-	AB906977
Poritidae	Goniopora somaliensis	IR61	MUFS YFK1074	Hatoma	Japan	AB907047	AB906978
Poritidae	Goniopora somaliensis	DJ019	UNIMIB DJ019	Ras Ali	Djibouti	AB907048	AB906979-80
Poritidae	Goniopora somaliensis	DJ073	UNIMIB DJ073	Oblal W	Djibouti	-	AB906981
Poritidae	Goniopora somaliensis	DJ198	UNIMIB DJ198	Ankali Outer	Djibouti	-	AB906982-3
Poritidae	Goniopora cf. somaliensis	MY100	UNIMIB MY100	N'goudja inner barrier	Mayotte, France	AB907049	AB906984
Poritidae	Goniopora stokesi	BU034	UNIMIB BU034	Burum	Yemen	AB907050	AB906985
Poritidae	Goniopora stokesi	BU039	UNIMIB BU039	Burum	Yemen	-	AB906986
Poritidae	Goniopora stokesi	BU063	UNIMIB BU063	Burum	Yemen	-	AB906987
Poritidae	Machadoporites tantillus	AD068	UNIMIB AD068	Aden	Yemen	AB907051	AB906988
Poritidae	Machadoporites tantillus	BA032	UNIMIB BA032	Bir Ali	Yemen	AB907052	AB906989
Poritidae	Machadoporites tantillus	BA070	UNIMIB BA070	Bir Ali	Yemen	AB907053	AB906990
Poritidae	Machadoporites tantillus	BA099	UNIMIB BA099	Bir Ali	Yemen	AB907054	AB906991
Poritidae	Goniopora tenuidens	AM85	MUFS YFK1157	Amakusa	Japan	AB907055	AB906992
Poritidae	Goniopora tenuidens	KS15	MUFS YFK319	Kushimoto	Japan	AB907056	AB906993
Poritidae	Goniopora tenuidens	OT15	MUFS YFK297	Otsuki	Japan	AB907057	AB906994
Poritidae	Goniopora tenuidens	OT18	MUFS YFK298	Otsuki	Japan	AB907058	AB906995
Poritidae	Goniopora tenuidens	TN53	MUFS YFK50	Tanegashima	Japan	AB907059	AB906996
Poritidae	Goniopora tenuidens	KK28	MUFS YFK810	Kikai	Japan	-	AB906997
Poritidae	Goniopora tenuidens	IS18	MUFS YFK934	Taketomi	Japan	AB907060	AB906998
Poritidae	Goniopora sp.1	BA078	UNIMIB BA078	Bir Ali	Yemen	-	AB906999
Poritidae	Goniopora sp.2	MU139	UNIMIB MU139	Al Mukallah	Yemen	-	AB907000
Poritidae	Goniopora stutchburyi	KS1	MUFS YFK101	Kushimoto	Japan	AB907061	AB907001-3
Poritidae	Goniopora stutchburyi	KS50	MUFS YFK148	Kushimoto	Japan	AB907062	AB907004
Poritidae	Goniopora stutchburyi	MO33	MUFS YFK866	Miyazaki-Oshima	Japan	-	AB907005
Poritidae	Goniopora stutchburyi	MO99	MUFS YFK1184	Kushima	Japan	-	AB907006
Poritidae	Goniopora stutchburyi	OU5	MUFS YFK614	Oura bay	Japan	-	AB907007-10
Poritidae	Goniopora stutchburyi	OU40	MUFS YFK768	Oura bay	Japan	AB907063	AB907011
Poritidae	Goniopora stutchburyi	OU51	MUFS YFK771	Oura bay	Japan	-	AB907012
Poritidae	Goniopora stutchburyi	SS21G	MUFS YFK220	Sesoko	Japan	AB907064	AB907013
Poritidae	Goniopora stutchburyi	PEN2	MSL/USM/SS002	Songsong	Malaysia	AB907065	AB907014
Poritidae	Goniopora stutchburyi	PEN5	MSL/USM/SS005	Songsong	Malaysia	-	AB907015
Poritidae	Goniopora stutchburyi	PEN22	MSL/USM/SS022	Songsong	Malaysia	-	AB907016
Poritidae	Goniopora stutchburyi	SS21G	MUFS YFK220	Sesoko	Japan	AB907064	AB907013
Poritidae	Stylaraea punctata	AK88	MUFS YFK1239	Akajima	Japan	AB907066	AB907017
Poritidae	Stylaraea punctata	AK89	MUFS YFK1240	Akajima	Japan	AB907067	AB907018
Poritidae	Stylaraea punctata	AK90	MUFS YFK1241	Akajima	Japan	AB907068	AB907019
Poritidae	Stylaraea punctata	AK91	MUFS YFK1242	Akajima	Japan	AB907069	AB907020
Poritidae	Stylaraea punctata	AK92	MUFS YFK1243	Akajima	Japan	AB907070	AB907021
Poritidae	Stylaraea punctata	AK93	MUFS YFK1244	Akajima	Japan	AB907071	AB907022
Poritidae	Stylaraea punctata	AK101	MUFS YFK1245	Akajima	Japan	AB907072	AB907023
Poritidae	Porites cf. lichen	SR128	MUFS YFK74	Shirahama	Japan	AB907073	AB907024
Poritidae	Porites sp.	AK32	MUFS YFK194	Akajima	Japan	AB907074	AB907025

Dash means no data.

Asterisk shows accession number referred from Kitano et al. [13]. Note that more than one ITS sequences were obtained by sub-cloning from a single specimen in several samples while ITS from other samples were determined by direct sequencing of PCR products. Museum abbreviations are as follows: MSL/USM: Universiti Sains Malaysia, MUFS: University of Miyazaki, Department of Fisheries Science ( = Department of Marine Biology and Environmental Science), Japan, SMBL: Seto Marine Biological Laboratory, Kyoto University, Japan, and UNIMIB: University of Milano-Bicocca, Department of Biotechnology and Biosciences, Italy.

Species identification

Species identification of Goniopora and Alveopora is difficult due to very limited skeletal characters and highly variable skeletal and polyp morphologies. The best solution to this common problem in the scleractinian corals is detailed analyses of the type material of each species [28], [29]. In order to minimize the risk of misidentification in this study, we firstly made lists of characters for species identification for these two genera (Tables S1, and S2) using the original descriptions and related references [1], [14], [15], [26], [35]–[60]. These tables were used to identify our specimens to species, examining the skeletal morphology of each specimen using a VHX-1000 digital microscope (Keyence) or stereoscopic microscope. Traditionally, species identification of Goniopora and Alveopora is based on skeletal characters, but recently Veron and Pichon [15], Nishihira and Veron [59], and Veron [1] added polyp characters to support species identification. Therefore, we also considered polyp characters along with skeletal characters for species identification in this study. The skeletal specimens collected in Japan are retained at University of Miyazaki (MUFS) or Seto Marine Biological Laboratory (SMBL). Skeletal specimens collected in Malaysia are deposited at Universiti Sains Malaysia (MSL/USM), and skeletal specimens collected in western Indian Ocean are at University of Milano-Bicocca (UNIMIB).

Genetic analyses

A small sample (less than 1 cm3) of each specimen was put in CHAOS solution to dissolve the tissues or fixed in 99% ethanol. Total DNA was extracted from CHAOS solution using the phenol/chloroform extraction method [61], and from the coral tissues preserved in ethanol using the DNeasy Blood & Tissue Kit (Qiagen). The barcoding region of the mitochondrial Cytochrome oxidase subunit I (COI) was amplified by the polymerase chain reaction (PCR) using the primers ZCO1 and ZCO1R [9]. The nuclear ribosomal ITS region (ITS) including the 3′ end of the 18s rRNA, ITS-1, 5.8s, ITS-2, and the 5′ end of the 28s rRNA was also amplified by PCR using the primers 1S and 2SS [62]. The PCR condition for these two markers was 94°C for 30 seconds followed by 30 or 35 cycles at 94°C for 30 seconds, 55°C or 60°C for 45 seconds, and 72°C for 90 seconds, with a final phase of 72°C for 5 minutes. For the mitochondrial region, PCR products were treated with Shrimp Alkaline Phosphatase (SAP) and Exonuclease I (ExoI) at 37°C for 40 minutes followed by 80°C for 20 minutes. The DNA sequences were then determined via a direct sequence method, using ABI3730 or ABI310 sequencer. PCR products of the nuclear marker were also directly sequenced, but when obtained sequences had more than double peaks in the chromatogram, they were sub-cloned into TA-vector (Promega) or TOPO10 (Invitrogen) and sequenced using ABI3730 or ABI310. All DNA sequences obtained in this study were submitted to DDBJ (accession No. AB906942–AB907101, listed in Table 1).

A total of 15 COI and 26 ITS Goniopora sequences were taken from our previous study ([13], see Table S3). Also, a number of sequences were downloaded from GenBank/DDBJ and included in the molecular analyses. For COI analysis, 30 sequences from 18 species of Porites ([9], Table S3), one sequence (AB441211 [19]) from Siderastrea siderea in the family Siderastreidae Vaughan an Wells, 1943, two sequences (AB441201–AB441202 [19]) from Galaxea fascicularis in the family Euphylliidae (Alloiteau, 1952), and two sequences (AB441216–AB441217 [19]) from Pavona spp. in the family Agariciidae Gray, 1847 (species name of AB441216 is registered as P. cactus in DDBJ, but it is revised P. decussata as the results of the reexamination of the skeleton). Also, in the family Acroporidae, four sequences (AF338425, AY451340–AY451342 [63], [64]) from three species of Acropora, one sequence (AY903296 [65]) from Montipora cactus and one sequence (AY903295 [65]) from Anacropora matthai were used. For ITS, 67 sequences from 18 species of Porites from previous study ([9], see Table S3) were used. Because there are many sequences of Porites for COI and ITS registered in GenBank, the sequences of representative species from each of the different phylogenetic groups reported by Forsman et al. [9], were selected for this study. Finally, as Fukami et al. [19] and Kitahara et al. [31] showed that the family Dendrophylliidae Gray, 1847 is genetically closely related to the family Poritidae, specimens of Turbinaria peltata (family Dendrophylliidae) from Japan were also sampled for this study.

Molecular phylogenetic analysis

Electropherograms and DNA sequences were checked and edited using Sequencher (Gene Code Co.) and SeeView 4.3.0 [66]. DNA sequences were aligned with MAFFT 7 [67] using the L-INS-i option. Then, all sites with indels and several sites with alignment ambiguities were excluded manually from the subsequent analyses. Two aligned DNA datasets (COI and ITS) used in this study are shown in supplementary information (Datasets S1, S2). Pairwise genetic distances were calculated as p-distance using MEGA 4.0.2 [68]. Phylogenetic trees were reconstructed by neighbor-joining (NJ) and maximum likelihood (ML). For NJ, PAUP* 4.0b10 [69] was used to infer the topologies for both COI and the ITS markers using Kimura 2-parameter model [70] and to conduct bootstrap analysis (1000 replicates). For ML, we assumed a model of nucleotide evolution obtained by using the Akaike Information Criterion (AIC) as implemented in MrModeltest 2.2 [71]. The most appropriate models of nucleotide evolution were TrN with invariant (I) and gamma (G) parameters (TrN+I+G) for the COI marker, and TrNef +I+G for ITS marker. PAUP* was used to reconstruct a best ML tree using a heuristic search and the tree-bisection-reconnection branch swapping method. GARLI (Genetic Algorithm for Rapid Likelihood Inference) 0.951 [72] was preferred to PAUP* for the bootstrap estimation as the former is less time consuming. Using GARLI, optimal ML topologies were searched with default setting using the models selected by MrModeltest (TrN+I+G for COI, TrNef +I+G for ITS) and bootstrap analyses (500 replicates) were conducted for each marker. MrBayes 3.2.2 [73] was also used to conduct Bayesian analyses under the same models. Four parallel chains of 1–4×106 generations were run for each marker. Trees were sampled every 100 generations, and the initial 25% of the total trees as burn-in were discarded. The remaining trees were pooled to produce a 50% majority rule consensus tree. The average standard deviation of split frequencies after 4×106 generations was 0.002069 for COI, and ones after 2.4×106 generations was 0.009967 for ITS. All topologies obtained in these analyses were quite similar, so that only the ML tree inferred using PAUP* is used in this study.

In addition, we combined COI and ITS data and analyzed them with same methods as each marker using the GTR+I+G model for the nucleotide substitution (the average standard deviation of split frequencies after 1.0×106 generations was 0.009909).

Nomenclature Acts

The electronic edition of this article conforms to the requirements of the amended International Code of Zoological Nomenclature, and hence the new names contained herein are available under that Code from the electronic edition of this article. This published work and the nomenclatural acts it contains have been registered in ZooBank, the online registration system for the ICZN. The ZooBank LSIDs (Life Science Identifiers) can be resolved and the associated information viewed through any standard web browser by appending the LSID to the prefix “http://zoobank.org/”. The LSID for this publication is: urn:lsid:zoobank.org:pub: 6975D790-3A4F-466A-ABFA-D922E6675B4B. The electronic edition of this work was published in a journal with an ISSN, and has been archived and is available from the following digital repositories: PubMed Central, LOCKSS.

Results

Twenty samples of Alveopora and 58 samples of Goniopora were analyzed in this study (Table 1). Although a few species have species-specific polyps, such as Goniopora albiconus, polyp characters vary greatly in the field. For example, terete tentacles, a typical polyp character of G. tenuidens, are also seen in G. burgosi.

All 7 specimens of Stylaraea punctata were found in very shallow water (1 m) on a sandy beach in Aakajima Island, Okinawa, Japan (Fig. 1). Notably, all of them were attached to dead coral skeletons of the genus Acropora. Their size is very small (less 1 cm) and they have only 5 or 6 corallites. Tentacle and septal numbers were both 12 in all of them (Fig. 2A–D).

Figure 2

Polyp and skeleton characters of Stylaraea punctata and Bernardpora stutchburyi.

A–B. Stylaraea punctata AK93, MUFS YFK1244, Akajima Island, Japan. C–D. S. punctata AK92, MUFS YFK1243, Akajima Island, Japan. E–H. Bernardpora stutchburyi SS21G MUFS YFK220, Sesoko, Japan. Living specimen for whole colonies (A, E) and polyps (B, F), corallite structures (C, G), and star-shaped columella (D, H). Arrows show columella. Bars show 1 mm for (C) and (G), and 0.5 mm for (D) and (H).

Poritipora paliformis Veron, 2000 has 24 septa with typically 2 septal cycles (long and short), 6 pali and no columella reported in the literature [24]. Two samples we collected in Taketomi Island, Japan (first record in the Pacific Ocean) had no elongating polyps in the field and had a cellular appearance (Fig. 3A), which is a feature of P. paliformis, as shown in Veron [1], [24]. The skeletal morphologies are also consistent in the literature, although the second cycle is not well developed in some corallites; however, many had 24 septa with 2 cycles (Fig. 3B). Therefore, we identified these 2 samples as P. paliformis. This species was described in Veron [1] without designating type material, and then it was redescribed [24] designating the holotype. However, the hototype of this species is not valid following ICZN [74], and the specimens listed in Veron [1] are regarded as part of the syntype series. Therefore, the holotype of this species listed in Veron [24] is to be considered a lectotype.

Figure 3

Polyp and skeleton characters of ‘Poritipora’ paliformis, ‘Machadoporites’ tantillus and morphologically related species.

Living specimens and corallite structures for P. paliformis IS48, MUFS YFK959, Taketomi, Japan (A, B) and M. tantillus AD068, UNIMBI AD068, Aden, Yemen (E, F), respectively. Corallite structures of holotypes of P. paliformis MTQ G55857 (C) and Goniopora minor NHMUK 1934.5.14.436 No. 56 (D). Corallites structures of G. burgosi OT6, MUFS YFK286, Otsuki, Japan (G) and G. pendulus TN11, MUFS YFK243, Tanegashima, Japan (H) from Japan water, as examples of corallites with less 24 septa. Bars show 1 mm.

Four specimens collected in the Gulf of Aden (Fig. 3EF), which is near the type locality of Machadoporites tantillus (Claereboudt & Al-Amri, 2004), were identified as M. tantillus because they are consistent with the original description of this species [23].

Diagnostic morphological characters among genera in the family Poritidae are summarized in Table 2.

Table 2

Comparison of the diagnostic morphological characters between the previous classifications and the classification used in this study in the family Poritidae.

Genus	Calice diameter (mm)	Number of septa	Septal arrangement	Columella structure	References
Previous study
Porites	0.5–2.2	12	Yes1	Central rod (tubercle) with a star-shaped granules if it develops	[1], [2], [15], [16], [78]
Goniopora	1.0–10.0	24	Yes3	Trabecular (fused septal dentations) if it develops	[1], [2], [15], [16], [26]
Stylaraea	<1	12	No	Central rod (tubercle) with a star-shaped granules	[1], [15], [46], [78]
Poritipora	2.0–2.5	24	No2	No	[1], [24]
Machadoporites	1.5	15–22	No	No	[81]
This study
Goniopora *	1.0–10.0	12–24	Yes3/No2	trabecular (fused septal dentations) if it develops	This study
Bernardpora gen. nov.	<2	24	Yes3	Central rod (tubercle) with a star-shaped granules	This study

Specific septal pattern for Porites, 23rd septa turn into 2nd septa ( = irregular reducing of gonioporoid pattern), 3Gonioporoid pattern.

*including Poritipora and Machadoporites as junior synonym.

COI phylogeny

We obtained 69 COI sequences from all 5 genera in the Poritidae with Alveopora, 3 sequences from Turbinaria peltata and Astreopora spp., and one from Montipora venosa (Table 1). A total of 473 positions were used (120 polymorphic sites with 109 informative sites) and no indels were observed. A phylogenetic tree was reconstructed using these data, including sequences from GenBank/DDBJ (see Methods). Siderastrea siderea was used as an outgroup, based on the phylogenetic position of the Scleractinia shown by Fukami et al. [19].

The COI phylogenetic tree showed that all 18 species of Porites are monophyletic. Moreover, the 13 Goniopora species we examined in this tree are also monophyletic, with the notable exception of G. stutchburyi (Fig. 4). This species and Stylaraea punctata are sister taxa (Fig. 2), and together they form a sister group to Porites. Machadoporites tantillus and Poritipora paliformis are nested within Goniopora (except G. stutchburyi). On the one hand, within the Goniopora phylogeny, M. tantillus forms a clade with the western Indian Ocean species G. somaliensis and G. cf. somaliensis. On the other hand, P. paliformis forms a clade with G. minor and G. columna, although G. somaliensis and G. minor are polyphyletic. Notably, all G. somaliensis from Japan are genetically distant from the G. somaliensis specimens from the western Indian Ocean. Uncorrected genetic p-distances between G. stutchburyi and Porites and between G. stutchburyi and the remaining Goniopora spp. were very similar (approximately 0.02).

Figure 4

Molecular phylogenetic relationships of the family Poritidae and related families based on mitochondrial COI sequences.

Numbers on/below main branches show bootstrap values (>50%) in ML and NJ analyses, and Bayesian posterior probability (>0.8). Stars show specimens collected from western Indian Ocean, and triangles show ones collected from Malacca Strait. Sample codes or accession numbers are shown after species names (see Table 1, Table S3). Grey in color for Alveopora, green for Porites, purple for Stylaraea, blue for ‘Poritipora’, and orange for ‘Machadoporites’. Goniopora is shown by bars in black. Bernardpora is shown by bar in red.

All samples of Alveopora are genetically distant from all other poritids (p-distance 0.08–0.10), but closely related to the family Acroporidae (0.06). The phylogenetic position of Alveopora is unclear due to low bootstrap values, but it forms a sister group with Astreopora spp. In addition, sequences from T. peltata (family Dendrophylliidae) form a sister clade of all poritids except Alveopora and are positioned between Alveopora and the other poritids.

ITS phylogeny

We obtained a total of 84 sequences of ITS from all 5 genera in the Poritidae (Table 1). In this study, we excluded Alveopora from ITS analysis because ITS regions were highly variable between Alveopora and other genera and they were hardly aligned.

The phylogenetic relationships among Porites, Goniopora, Stylaraea, Poritipora, and Machadoporites were inferred using ITS (Fig. 5). The 68 Porites sequences from Forsman et al. [9] and 26 Goniopora sequences from Kitano et al. [13] were also added for this analysis (see Table S3). A total of 347 positions were used (108 polymorphic sites with 89 informative sites). This ITS tree also showed similar topology to the COI tree as described above. In particular, Stylaraea punctata and G. stutchburyi are sister taxa. Poritipora paliformis formed a clade with G. minor and G. columna. One specimen of G. minor in the Poritipora clade is from the western Indian Ocean and others are from Japan. Machadoporites tantillus formed a clade with G. somaliensis and another 3 species (G. cf. somaliensis, G. sp.1, and G. sp.2), all of which were collected from the western Indian Ocean. Other western Indian Ocean specimens (G. albiconus, G. ciliatus) and Malacca Strait specimens (G. albiconus, G. pendulus) were included in a major clade of Goniopora spp. Meanwhile, species relationships of Goniopora were less resolved because Porites and Goniopora have many indels in their rDNA sequences and phylogenetic information sites were largely excluded.

Figure 5

Molecular phylogenetic relationships of genera of the Poritidae except of Alveopora based on ITS sequences.

Letter (a, b, c, d) after sample code indicates that different alleles were obtained from a single coral sample by cloning. Numbers on/below main branches show bootstrap values (>50%) in ML and NJ analyses, and Bayesian posterior probability (>0.8). Stars show specimens collected from western Indian Ocean, and triangles show ones collected from Malacca Strait. Sample codes or accession numbers are shown after species names (see Table 1). Green in color for Porites, purple for Stylaraea, blue for ‘Poritipora’, orange for ‘Machadoporites’, red for Bernardpora, and black for Goniopora.

The tree using combined data of COI and ITS showed a similar topology to the one for ITS (Fig. S1).

Discussion

Phylogenetic relationships of Goniopora, Stylaraea, and Porites

Our molecular data showed that Goniopora can be divided into 2 distinct groups (Figs. 4, 5). One contains most Goniopora species together with Machadoporites and Poritipora, whilst the other is monospecific for G. stutchburyi. Moreover, G. stutchburyi is monophyletic with Stylaraea punctata and these 2 species form a sister group to all Porites. Stylaraea punctata has very unique morphological characters among the zooxanthellate scleractinian corals, such as the smallest (less 1 cm) mature colony size with only 5 or 6 corallites [25 and our observation of the release of zooxanthellate planulae from samples AK92 (maximum diameter 7.15 mm) and AK93 (4.00 mm)], and 12 septa ( = 12 tentacles) without a specific septal pattern such as in Porites or Goniopora. Moreover, the calices of this species are devoid of pali. Thus, these features allow to distinguish Stylaraea from the other genera in this family. Although Alveopora can bear resemblance to Stylaraea, the two genera can be distinguished based on the columella (not present or very weakly developed in Alveopora and star-like columella in Stylaraea) and the elongation of polyps (long polyps for Alveopora and no elongation for Stylaraea). Goniopora stutchburyi also has its own specific characters, such as coralla that appear to have a smooth surface, dense septa and a columella composed of a star-shaped central rod (Figs. 2G, H). Thus, G. stutchburyi is easily distinguishable from all other congeneric species. Although the smooth appearance of the skeleton of this species and small corallite size may lead to misidentification as Porites, G. stutchburyi can be differentiated from Porites on the basis of its septal number (24 vs. 12). Thus, morphologically, the only character shared by S. punctata and G. stutchburyi is a columella composed of a star-shaped central rod (Figs. 2D, H), which is absent in other Goniopora species but common in Porites. This type of columella could be a synapomorphy in the lineage including Porites, Stylaraea, and G. stutchburyi. Considering that molecular and morphological data agree in distinguishing G. stutchburyi from the other Goniopora species and S. punctata, we establish Bernardpora Kitano & Fukami gen. nov. (urn:lsid:zoobank.org:act:9C2FE523-A491-45AE-BC22-B528CA68C040, also see below for details) and move G. stutchburyi into it. Comparison of diagnostic morphological characters between genera is summarized in Table 2.

Bernard [26] proposed that the septal formula of Porites derives from that of Goniopora by reduction of the third septal cycle, referring to the typical septal pattern of Goniopora as the gonioporoid pattern. Veron and Pichon [15] showed that G. stutchburyi typically has this septal pattern (Fig. 2G). In this study, we proved that G. stutchburyi is a basal species of Porites, and our results strongly support Bernard's hypothesis that Porites is derived from Goniopora-like morphologies. This conclusion is also supported by the fossil record: Goniopora extends back to the Cretaceous, but Porites only to the Eocene [16]. Thus, the presence of 24 septa would seem to be an ancestral feature in the Poritidae. The fact that taxa in the family Dendrophylliidae, the closest related outgroup of the Poritidae, have more than 24 septa would appear to support this.

According to Veron and Pichon [15] and Veron [1], Goniopora burgosi and G. somaliensis are morphologically similar to G. stutchburyi in corallite size and height, respectively. Furthermore, G. burgosi appears to form only 12 septa as a third cycle of septa is reduced or absent in whole colonies, as is typical of Porites (Goniopora usually forms 24 septa). However, in our genetic analysis, G. burgosi and G. somaliensis were included in the major Goniopora clade, and their phylogenetic position was distant from Porites even though they have fewer than 24 septa. The typical gonioporoid pattern was also observed in some colonies of G. lobata and G. djiboutiensis, but they were not closely related to G. stutchburyi. These results suggest that each of these morphological characters alone (corallite size, depth, and septal formula) would not be sufficient to explain the species relationships in this genus.

Phylogenetic position of Alveopora

None of the 8 species of Alveopora we analyzed is closely related to Goniopora, despite the 2 genera having similar elongating polyps and tentacles. This suggests that the typically elongated polyps in these genera have appeared independently as result of convergent evolution. Alveopora is also genetically distant from Porites. Both genera have 12 tentacles (12 septa), but our genetic data indicate that this character is not synapomorphic, which is also supported morphologically by the difference in septal plan in both genera (spin-like for Alveopora and fused for Porites). Bernard [26] asserted that Alveopora did not belong to the Poritidae, and Veron and Pichon [15] also cast doubt on this classification. Along with our genetic data, the morphological differences between Alveopora and other genera in the Poritidae, which have previously been noted [15], support the hypothesis that Alveopora does not belong in the Poritidae. Wallace [21] also noted that Alveopora has the Acroporidae characteristic of synapticulothecate skeleton but does not have coenosteum. As reported by previous studies, the phylogenetic position of Alveopora is close to the Acroporidae [18], [19], [31], [62]. The ITS of Alveopora is also very divergent, a characteristic shared by acroporids, but not observed in other families [62]. However, the phylogenetic position of Alveopora is still unclear because different topologies (forming a sister group with Astreopora or outside of Astreopora) were also obtained in COI (Fig. 4) and rDNA [62] trees. Our preliminary analyses of rDNA also showed that Alveopora was positioned outside of the Astreopora (data not shown). A complete evaluation of the phylogenetic position of Alveopora is outside the scope of this study. To perform such an evaluation, morphological comparison among all genera of Acroporidae would be necessary (Wallace et al., in preparation).

Phylogenetic relationships of the monospecific genera Stylaraea, Machadoporites, and Poritipora

Poritipora and Machadoporites are found within the Goniopora lineage in all molecular phylogenetic trees. This is supported by morphology. Machadoporites differs from Goniopora by having fewer septa (fewer than 24) and smaller calices (<1.7 mm). However, some Goniopora species can have superficially similar characters. For example, G. burgosi has typically 12–15 septa, as shown in the original description ([51], Fig. 3G). A similar pattern is also observed in G. pendulus (Fig. 3H). Moreover, the G. minor calices were described as 1.5–2 mm in size in the original description [50]. Thus, characters such as “fewer than 24 septa,” and “small size calices” are not enough to separate Machadoporites from Goniopora. In addition, M. tantillus forms a clade with G. somaliensis and other Goniopora species from the western Indian Ocean.

Similar to Goniopora, Poritipora has 24 septa, but the 2 genera can be distinguished by the difference in the number of septal cycles: 2 in P. paliformis and 3 in Goniopora. However, for several Goniopora species, primary and secondary cycles of septa are equal or subequal, such as in the case of G. minor (Fig. 3D). Therefore, the character “two cycles of septa” is not enough to separate Poritipora from Goniopora. In addition, P. paliformis forms a clade with G. minor and G. columna.

On the one hand, Machadoporites and Poritipora are considered junior synonyms of Goniopora and their taxonomy is hence revised hereafter.

On the other hand, the type material of P. paliformis (Fig. 3C) and our samples (Fig. 3B) look similar to the type material of G. minor (Fig. 3D) shown in Crossland [50]. Goniopora minor has a similar size of corallites, 12 equally sized septa for the primary and secondary cycles, small or absent septa in tertiaries, and 4–6 pali. The development of the columella was described as “large,” but it is composed only of joined septa, which is the same pattern as that of Poritipora. Considering that most G. minor examined in this study (one colony of G. minor was genetically separated; Figs. 4 and 5) formed a clade with P. paliformis with little genetic difference, P. paliformis may be a morphological variant of G. minor.

Regional differences

Our specimens were collected mostly from Japanese waters, but some of them including Machadoporites were collected from the western Indian Ocean and the Malacca Strait. Although several species from these regions, such as G. albiconus and G. ciliatus, were included in the clade with specimens collected from Japanese waters, 4 specimens, including G. somaliensis from the western Indian Ocean, formed their own clade, whereas G. somaliensis from Japanese waters was distant from the western Indian Ocean clade and included in a major clade of Goniopora spp. This suggests that morphological convergence may have occurred between the western Pacific and the western Indian Ocean populations of these species. Recently, Arrigoni et al. [75] showed that numerous cases of intraspecific divergence between Indian Ocean and Pacific Ocean populations were present in the families Merulinidae and Lobophylliidae. Moreover, Keshavmurthy et al. [76] reported that a widely distributed species, Stylophora pistillata, comprises 4 divergent clades corresponding to different regions, such as the western Pacific and the Red Sea, suggesting that their clades are divergent at the species level. A similar observation on divergence was made with regard to the octocoral family Melithaeidae [77], indicating that species did not cluster according to their present morphological classification but instead clustered according to a biogeographical pattern such as the Indo-Pacific, Red Sea and Indian Ocean. Thus far, many studies of scleractinian corals have focused on higher level taxonomy and are based on material sampled from one or a few nearby Indo-Pacific regions. However, species-level analyses among regions are the next necessary step in the ongoing revolution in scleractinian taxonomy.

Taxonomic account

Below we propose the description of the new genus Bernardpora gen. nov. and the revised diagnosis of Goniopora, based on the original descriptions and subsequent information resulting from this study. See Table 1 for the museum abbreviations.

Family Poritidae Gray, 1847

Type genus: Porites Link, 1807

Diagnosis [1], [16], [60]: Massive, laminar or ramose colonies; corallites vary in size but usually small and mostly compacted closely without coenosteum, with one or two synapticular rings. Walls and septa are porous. Septa usually 12 to 24. Septa formed by 3 to 8 nearly vertical trabeculae, and innermost trabeculae of certain septa differentiated as pali.

Remarks: There are four extant genera in Family Poritidae, Porites, Goniopora, Stylaraea and Bernardpora gen. nov. All are zooxanthellate corals. Porites is the only genus distributed throughout the tropics. Others are Indo-Pacific. Based on our results we confirm that the genus Alveopora does not belong to the same lineage as the family Poritidae. Although a full evaluation of the position of Alveopora is not completed yet, it is certain that Alveopora is closely related to other genera in the family Acroporidae ([20], this study).

Genus Porites Link, 1807

Type species: Porites polymorphus Link, 1807: 163 ( =  Madrepora porites Pallas, 1766:324–326, Neotype: MHNNP Lamarck Collection No. 150 (figured in Jameson & Cairns, 2012, figs 4D, 5). This specimen is also the holotype of Porites clavaria Lamarck, 1816 [78], [80])

Generic synonymy [2], [16], [78]

- Neoporites Duchassaing & Michelotti, 1864: 97. Type species is not fixed.

- Cosmoporites Duchassaing & Michelotti, 1864: 99. Type species: Cosmoporites laevigata Duchassaing & Michelotti, 1864: 99. Holotype: unknown (figured in Duchassaing & Michelotti, 1864: 99, pl. x, figs. 12, 16. Bernard [79] described ‘the type specimen was not found by Count Peracca in the Turin Museum’.)

- Synaraea Verrill, 1864: 42. Type species: Porites erosa Dana 1846: 565–566, pl. 55, fig. 8. Holotype: USNM 668

- Napopora Quelch, 1884:296. Type species: Napopora irregularis Quelch, 1884: 296–297. Holotype: NHMUK 86.12.9.302.

Diagnosis [1], [16], [78]: Colonies massive, ramose, laminar, or encrusting. Corallites are small, immersed, circular or polygonal. Calice diameter 0.5–2.2 mm. Septa are 12 in number, composed of 1 to 4 trabeculae. The typical formula of septal arrangement in this genus, with some of its variations, is seen. Pali are present, variable development in different species, usually 4–8 in number. Mural trabeculae always present. Columella trabeculae usually present with star-shaped granules. The wall is really simple, but the incipient synapticulae, seen starting from the sides of septal granules, may become complete and form an inner synapticular wall.

Remarks: Distribution: Indo-Pacific and Atlantic [1]. Species number: 73[1], [15]

Genus Goniopora de Blainville, 1830

Type species: Goniopora pedunculata Quoy & Gaimard, 1833:218–220, pl. 16, Figs. 9–11. The type specimen appears to be lost [15].

Generic synonymy [2], [16], [26]

- Rhodaraea Mile Edwards & Haime, 1849: 259. Type species: Astraea calicularis, Lamarck 1816: 266. Holotype: unknown.

- Tichopora Quelch, 1886:188. Type species: Tichopora tenella Quelch, 1886: 189, pl. 11, figs. 1, 1a. Type specimens: NHMUK 86.12.9.342.

- Poritipora Veron, 2000:347. Type species: Poritipora paliformis Veron, 2000: 347. lectotype: MTQ G55857

- Calathiscus Claereboudt & Al-Amri, 2004. Type species: Calathiscus tantillus Claereboudt & Al-Amri, 2004 (This species is also type species of the genus Machadoporites). Holotype: SQU040001.

- Machadoporites Nemésio, 2005. Type speices: Calathiscus tantillus Claereboudt & Al-Amri, 2004.

Revised diagnosis [1,16,26,this study]: Massive, columnar or ramose, rarely encrusting colonies. Corallites are circular or polygonal. Calice diameter 1–10 mm. Septa 24 in two or three cycles, or between 24 and 12 in two or three cycles, composed of 4 to 8 trabeculae. Pali and columella may develop. Columellae are composed of anastomosed septal dentations or arranged synapticula and fused inner ends of septa. Wall structure is synapticulothecal. Polyps usually elongate during the day (note that G. paliformis does not elongate polyps during the day).

Remarks: Poritipora and Machadoporites are considered as junior synonyms of Goniopora. Distribution: Indo-Pacific [1]. Species number: 33 [1,15,this study].

Genus Stylaraea Milne Edwards & Haime, 1851

Type species: Madrepora punctata Linnaeus, 1758:795. The specimen ZMB #956 may be Syntype [78] (examined).

Diagnosis: Stylaraea is a monospecific genus with only known species, S. punctata. Therefore, the characters of this genus are those of S. punctata. Colonies are tiny (usually less 10 mm in size) and from “cushion-shaped crusts”[46]. Calices are concavate and around 1 mm diameters. Septal number is 12 (“2 cycles of 6 each” [15]) without specific septal pattern. Septa are composed of rows of star-shaped granules. Primary septa may reach to collumellae. Columella is composed of a star-shaped central rod such as Porites or Bernaldopora. Wall structure is synapticulothecal.

Remarks: Distribution: Indo-Pacific [1]. Species number: 1

Genus Bernardpora Kitano & Fukami gen. nov.

urn:lsid:zoobank.org:act:9C2FE523-A491-45AE-BC22-B528CA68C040

Type species: Goniopora stutchburyi Wells, 1955: 11, pl. 1, figs 1–2; Holotype: MTQ G2931 (examined)

Diagnosis: Bernardpora is a monospecific genus with only known species, B. stutchburyi. Therefore, the characters of this genus are those of B. stutchburyi. Encrusting or sub-massive colonies. Corallites round to polygonal and very shallow with smooth appearance. Calices are around 2 mm diameters. Septal number is mostly 24 with clear gonioporoid pattern shown in Bernard [26]. Septa are dense with up to seven multiple-spine-shaped septal teeth. Septal teeth closest to collumellae are indistinguishable from pali. Primary and secondary septa nearly reach to collumellae. Columella is composed of a star-shaped central rod such as Stylaraea and Porites. Wall structure is synapticulothecal. Polyps elongate but very short during the day.

Remarks: Distribution: Indo-Pacific [1]. Species number: 1

Etymology: The generic name is in honor of the coral scientist Henry M. Bernard.

Molecular phylogenetic relationships of genera of the Poritidae except of based on combined COI+ITS sequences. Numbers on/below main branches show bootstrap values (>50%) in ML and NJ analyses, and Bayesian posterior probability (>0.8). Stars show specimens collected from western Indian Ocean, and triangles show ones collected from Malacca Strait. Sample codes or accession numbers are shown after species names (see Table 1, Table S3). Grey in color for Alveopora, green for Porites, purple for Stylaraea, blue for ‘Poritipora’, and orange for ‘Machadoporites’. Goniopora is shown by bars in black. Bernardpora is shown by bar in red.

(TIF)

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Nexus data file of the COI sequence alignments used for the analyses.

(NXS)

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Nexus data file of the ITS sequence alignments used for the analyses.

(NXS)

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Summary of the diagnostic morphological characters for species identification of the genus Goniopora. Original descriptions are shown in bold.

(XLS)

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Summary of the diagnostic morphological characters for species identification of the genus Alveopora. Original descriptions are shown in bold.

(XLS)

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List of poritid samples and accession numbers for COI and ITS, referred from previous study.

(DOCX)

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