Coelastrea

Verrill, 1866, p. 32

Type Species

Coelastrea tenuis Verrill, 1866, p. 33; Original Designation Verrill, 1866, p. 33

Type Specimen: Holotype; YPM IZ 476; Verified; Dry Preserved

Type Locality: 'Sandwich Islands?' (Recent)

Classification

• Family: Merulinidae Verrill, 1865, p. 146

Diagnosis

Colonial, with intracalicular budding only. Corallites monomorphic and discrete (1–3 centers); monticules absent. Coenosteum costate, limited amount (includes double wall) or fused walls. Calice width medium (4–15 mm), with medium relief (3–6 mm). Costosepta not confluent. Septa in ≥ 4 cycles (≥ 48 septa). Free septa regular. Septa spaced 6–11 septa per 5 mm. Costosepta equal in relative thickness. Columellae trabecular and spongy (> 3 threads), < 1/4 of calice width, and continuous among adjacent corallites. Septal (multiaxial) lobes well developed. Epitheca well developed and endotheca low-moderate (tabular). Tooth base at mid-calice circular. Tooth tip at mid-calice irregular; tip orientation perpendicular to septum. Tooth height medium (0.3–0.6 mm) and tooth spacing medium (0.3–1 mm), with > 6 teeth per septum. Granules scattered on septal face; irregular in shape. Interarea palisade. Walls formed by dominant paratheca and partial septotheca; trabeculothecal elements may be present; abortive septa absent. Thickening deposits fibrous. Costa center clusters weak; 0.3–0.6 mm between clusters; medial lines strong. Septum center clusters weak; 0.3–0.5 mm between clusters; medial lines strong. Transverse crosses present. Columella centers clustered.

Description

'Corallum massive, cellular, fasciculate, formed by prismatic coralites [sic] intimately united by their walls which are thin and simple. The exterior of the corallum is destitute of an epitheca, lobed and distinctly costate like that of Metastrea. The cells are polygonal, often closed below by the dissepiments, which, occuring [sic] at the same level, unite from all sides forming thus transverse septa. In a transverse section traces of a very rudimentary and loose columella are seen in some cells. Septa in three or four cycles, unequal, the inner edges prolonged into strong paliform teeth. The polyps increase by fissiparity, and near the margin by disk-budding. This genus appears to bear the same relation to Goniastrea that Metastrea does to Prionastrea, differing from it in the absence of epitheca and the lobed and striated exterior, thinness of the walls, and rudimentary columella. From Metastrea it differs in the last character, and in its mode of increase as well as in the coincidence of the dissepiments and the strong pali.' (Verrill, 1866: 32)

Comparisons

Coelastrea is a well-supported clade. Two synapomorphies have been identified for this genus: limited coenosteum or fused walls, and presence of regular free septa. These apomorphies distinguish it from closely-related genera, in particular Dipsastraea and Trachyphyllia, but they are also present in part among Goniastrea. Most Goniastrea spp. have fused walls, and regular free septa are present in Goniastrea retiformis and G. stelligera. Other characters, mostly subcorallite ones, are more useful for separating Coelastrea and Goniastrea, e.g. more septa (≥ 4 cycles), parathecal walls and the lack of abortive septa, strong costa and septum medial lines, and transverse septal crosses in Coelastrea. The present phylogenetic analysis is based on the clade Coelastrea aspera + C. palauensis. Coelastrea tenuis, if valid, most resembles C. aspera, differing only in the lack of spongy columellae, and in some corallites, having no columella at all. Its corallites are also more irregular in terms of size and shape (see Vaughan, 1907: 105).

Remarks

Coelastrea was described by Verrill, 1866: 33 based on the type specimen of C. tenuis collected by Dana during the US Exploring Expedition (1838–1842). The original museum label states 'Sandwich Islands?', referring tentatively to Hawai'i. The genus description was subsequently reproduced in Leuckart, 1869: 214 and Vaughan, 1907: 104, pl. 26: figs 2, 2a. The latter furthermore repeated Verrill's description of the species, which was listed by Studer, 1901: 398 as one of several species from Hawai'i described by Verrill. An unidentified Coelastrea sp. from the locality was also figured in Bryan, 1915, pl. 111: fig. 12. Coelastrea was recognized as a distinct genus in Vaughan and Wells, 1943: 168 with a note regarding its type locality being 'reputedly the Hawaiian Islands'. It was later synonymized by Wells, 1956: F402 with Goniastrea. The status of the type species was not addressed, although it was presumably transferred into Goniastrea. More recently, Chevalier and Beauvais, 1987: 714 listed Coelastrea as a valid genus and added Malaysia to its known range. However, there is much doubt that any living specimen has been collected since the initial description, certainly not in Hawai'i (D. Fenner, pers. comm.) where Goniastrea is not known to be present (Veron, 2000; Veron et al., 2009). Records of live Coelastrea tenuis being exported out of El Salvador in the eastern Pacific and an unspecified locality in USA between 1996 and 1997 were reported by CITES (2001), but these were not substantiated by voucher collections and thus most likely misidentifications. Fossil corals from Plio-Pleistocene of Nias, an island off western Sumatra, Indonesia, were attributed to this species as Goniastrea tenuis by Boekschoten et al., 1989: 118, along with G. edwardsi and G. pectinata. We posit that Coelastrea tenuis may have been identified as Goniastrea aspera Verrill, 1866: 32 in more recent treatments, but without a more extensive investigation, we are unable to verify the species status of C. tenuis. On the bases that Goniastrea aspera and Favia palauensis Yabe and Sugiyama, 1936: 30, pl. 19: figs 5, 6 match C. tenuis in nearly all macromorphological characters (i.e. lack of spongy columellae in C. tenuis), and that they are distinct from the rest of the Goniastrea on both molecular and morphology trees, we resurrect the genus Coelastrea and transfer these species into it.

Distribution

• Indian Ocean; Recent
• Western Pacific; Recent
• Central Pacific; Recent

This page has been in preparation since 18-Jul-2010 20:56

This version was contributed by Danwei Huang on 05-Feb-2014 19:26.

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