Psammocora albopicta, Benzoni, 2006

Benzoni, Francesca, 2006, Psammocora albopicta sp. nov., a new species of Scleractinian Coral from the Indo-West Pacific (Scleractinia; Siderastreidae), Zootaxa 1358 (1358), pp. 49-57 : 51-55

Psammocora albopicta sp. nov.

Figs. 1, 2, 3

Psammocora superficialis Carpenter et al., 1997: 52 and Figs. therein; Harrison, 1998: 181–2 Fig 3 Psammocora vaughani Hoeksema & van Ofwegen, 2004

Psammocora sp. nov.? Yabe, Sugiyama & Eguchi, 1936, Pl. XLV, Fig. 9

Material examined/types. Holotype: Kubbar Island , Kuwait (29°04’N, 048°28’E), 5 m, 18/09/2004, MSNM 332 . Paratypes: Umm Al-Maradem , Kuwait (28°40’N, 048°39’E), 5 m, 21/09/2004, MSNM 333; Qit’at Benaya, Kuwait (28°36’N, 048°25’E), 7 m, 23/09/ 2004, MSNM 334; Balhaf, Yemen (13°58’N, 048°12’E), 4 m, 10/09/2005 coll. F. Benzoni, MSNM 335 . Other material examined: Jana Island , Saudi Arabia (27°22’N, 049°54’E), 10 m, NHM 1978.2.2.1; Pulau Telor, Malaysia (05°23’N, 100°05’E), 1978, coll. C. Betterton, NHM 1979.9.23.34; Misool, Iran Jaya, Indonesia (02°00’S, 130°37’E), 10–28 m, 04/11/2002, coll. E. Turak, MTQ G57714 ; Point Vernon , Australia (25°14’S, 152°49’E) , coll. P. Harrison, JCU PH14; Gneering Shoals , Australia, (26°14’S, 153°49’E) , 06/07/1993, coll. P. Harrison, JCU PH 172 ; same locality, 16/06/1992, coll. P. Harrison and V. Harriott , JCU PH378; Cook Island, Australia (28°11’S, 153°34’E) , 1997, JCU PH628; Julian Rocks , Australia (28°37’S, 153°37’E) , 01/01/1995, coll. S. Banks and V. Harriott , JCU PH173; Australia, Moreton Bay , 2005, coll. C. Wallace, MSNM 336; Wellington Point, Moreton Bay, Australia, MTQ G57801 .

Description

Skeletal characteristics (based on holotype). The holotype ( Fig. 1) is part of an encrusting colony and 9 cm long, 4.5 cm wide, and 2.5 cm thick. Corallum density is between 50 and 66 corallites/cm 2 ( Table 1). Corallites can be even with the skeleton

surface, or at the bottom of shallow depressions delimited by rounded collines, or ridges, which can develop in parts of the corallum. Corallites found between collines can be arranged in short series (2 to 4 corallites). Calice diameter ranges from 0.9 to 1 mm. The average diameter of the calicular fossa is 0.3 mm (± 0.04 S.D.). The columella is a single peg, round, oval or almost cross-shaped in section. Seven to nine septa reach the fossa. Among these 3 or 4 are not fused with other septa, and can be petaloid or lamellar in shape, while the remaining ones are the result of the typical septal fusion found in the genus. Upper septal margins carry well developed granulations. Enclosed septa around the calice form one or two complete series, are mostly lamellar in shape, but can be petaloid in very smooth and compact parts of the skeleton. The shape of septa and the development of septal ornamentation is very variable. In the holotype septa go from petaloid, compact and flush with the corallum surface ( Fig. 1a), to petaloid and lamellar ( Fig. 1b), only lamellar ( Fig. 1c), and to very thin and markedly exert, giving the corallum a hirsute appearance ( Fig. 1d). SEM images of parts of the holotype at the two extremes of the gradient described above show that the septal ornamentation development and shape can be very different within the same colony. In the smoother part corallites are flush with the corallum surface and the skeleton appearance is very compact ( Fig 2a). Septa are regularly spaced ( Fig 2b) and their ornamentation consist of clusters of spiny processes (3 to 5) approximately 80 to 120 µm wide ( Fig 2c). In the spiny part calices outline is hardly distinguishable at first sight ( Fig 2d) and septa are exert ( Fig 2e) and irregularly arranged. Septal ornamentation is broadly similar to that on the smoother parts, but is much more heavily calcified and encrusted with rough granular to rounded processes (about 7 to 12 in total) ( Fig 2f) presenting a rougher surface.

Field characteristics and identification. P. albopicta forms encrusting colonies ranging from a few centimetres to more than 1 m in diameter ( Fig. 3a,b). The corallum usually follows the underlying substrate and can become massive or irregularly shaped according to the substrate shape ( Fig. 3a,b). The surface of the corallum can be smooth and even (usually in shaded parts of the colony) or undulating (in well lit parts) ( Fig. 3c), and knobs or nodules can be found scattered on it. Colour ranges from dark green to brown ( Fig. 3c,d). In most of the colonies observed in vivo parts of the surface present lightercoloured or white patches. These occur in two forms: a) corresponding to the tops of the irregularly scattered ridges between corallites forming linear patterns, ( Fig. 3c), and b) as almost circular rings ( Fig. 3d). The two patterns can be found on the same colony ( Fig. 3e). At first this lighter colouration was thought to depend on localized death of the polyps, possibly due to the deposition of sediment ( Fig. 3d), or to some other external cause. A closer look at the colonies in vivo, however, showed that living polyps with extended tentacles are found in both lighter ( Fig. 3g) and darker zones hence that the white colouration is not apparently due to the death or damage of the living tissue.

Comparisons. Among the other Psammocora species P. albopicta is closer to Psammocora nierstraszi Van der Horst, 1921 ( Fig. 4a and b, Table 1), both species having small corallites and fossa, a styliform columella, and forming large encrusting colonies. A comparison of the type material of the two species, however, shows that P. nierstraszi has significantly less corallites per square cm and the distance between adjacent corallite series is larger ( Table 1), due to the presence of more rows of enclosed septa than in P. albopicta ( Fig. 4b). The enclosed septa are mostly petaloid and often exert above the corallum surface in P. nierstraszi , but not in P. albopicta . Collines are less developed in P. albopicta than in P. nierstraszi . The typical hydnophoroid protuberances found in P. nierstraszi are absent in P. albopicta .

P. albopicta has been previously identified as Psammocora superficialis by Carpenter et al., 1997 and Harrison, 1998. However P. superficialis Gardiner, 1898 ( Fig. 4c) has larger corallites and larger fossa ( Table 1), a columella made of one central process and 4 to 6 small processes surrounding it ( Gardiner, 1898) and low acute collines. Finally the number of corallites per square cm in P. superficialis is roughly half that in P. albopicta ( Table 1).

Yabe and Sugiyama (1936) published a good illustration of a specimen which they identified as a possible new species ( Psammocora sp. nov.?, IGPTU 40983, Pl. XLV, Fig. 9) from Udo, Japan. The species, however, was never described, and the specimen could not be located in the IGPTU collections. Corallite density, diameter, columella size and structure, number of septa and distance between corallites match the description of P. albopicta given above.

Hoeksema and van Ofwegen (2004) identified as Psammocora vaughani Yabe & Sugiyama, 1936 a colony from the Philippines presenting in vivo the typical circular white pattern described above for P. albopicta . The holotype of P. vaughani (IGPTU 44975) could not be located (Nemoto Jun in litteris), but the skeleton characters visible in the original illustration (Pl. XLI, Fig. 7) resemble very closely those of P. nierstraszi .

Etymology. The species name (from the latin alba = white, and picta = painted) refers to the typical white patterns “painted” on the living coral.

Distribution. P. albopicta has an Indo-West Pacific distribution. The species is presently known from a few localities in the Arabian Gulf, in the Gulf of Aden, and from Malaysia, Indonesia and south-east Australia ( Fig. 5). Additional records from published illustrations extend the species distribution to Japan (Yabe & Sugiyama, 1936) and the Philippines (Hoeksema & van Ofwegen, 2004, exact locality not recorded).