Paraclavarina, VERON, 1985: 179

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 : 330-332

GENUS PARACLAVARINA VERON, 1985: 179 ( FIG. 20 )

Type species

Clavarina triangularis Veron & Pichon, 1980: 223 , figs 375–384; original designation, Veron, 1985: 179.

Original description

‘ Paraclavarina is like Merulina except that it is ramose without any development of laminae. It is the only fully ramose genus in the Merulinidae .

The description of Clavarina triangularis by Veron & Pichon (1980) is repeated below.

“Colonies, which frequently exceed 1 m diameter, resemble those of Hydnophora rigida in consisting entirely of a network of anastomosing branches without any plate-like or foliaceous basal attachment. Some colonies have lax, open branching, while others are compact and bushy. Old branches may be up to 1.5 cm thick; most average 1 cm except towards the tips where they taper. All branches are basically triangular in section and have three series of centres, one on each side, with the angles being the common walls. On most branches the series of centres are straight and divide only when the branch divides. Thicker branches may have more irregular series with frequent divisions not associated with sub-branches and branch sections may be more circular than triangular. Branch tips are threepointed star-shaped in section, with the centres lying along the valleys and the walls forming the points. Septa are in two alternating orders. First order septa are slightly exsert, either adjoined over the wall or, more usually, separated by a groove. They increase in thickness towards the “valley” axes and most curve towards the nearest centre. Their inner margins, which are mostly vertical, may have large dentations. However, most skeletal structures at the centres and along the valley axes are fused together so that the centres are star-shaped, consisting of 5–10 thick, radiating septa with fused inner margins and deep inter-septal loculi. Second order septa are short and usually thinner than those of the first order. All septa are dentate, those of the first order usually more so than those of the second. Centres are linked by a single, sometimes very thick, laminar plate, which itself is fused to adjacent septa. There are no clearly defined calices and valleys are often very superficial. Columellae may be trabecular or spongy, but are only distinguishable as such near branch tips. Individual centres and the perimeter of oral discs are clearly defined in living coralla. When polyps are expanded at night, fine, elongate tentacles usually occupy most of the space between the branches. Colonies are pale yellow or cream.” ( Veron & Pichon, 1980: 225)’ ( Veron, 1985: 179–180).

Subsequent descriptions

Veron, 1986: 438; Veron, 2000, vol. 2: 374.

Diagnosis

Colonial, with intracalicular budding only. Corallites monomorphic, uniserial, and ramose; monticules absent. Walls fused. Calice width small (<4 mm), with low relief (<3 mm). Costosepta confluent. Septa in <three cycles (<24 septa). Free septa present but irregular. Septa spaced six to 11 septa per 5 mm. Costosepta equal in relative thickness. Columellae trabecular but compact (one to three threads), <1/4 of calice width, and continuous amongst adjacent corallites. Paliform (uni- axial) lobes well developed. Epitheca absent and endotheca sparse ( Fig. 20 ).

Species included

Paraclavarina triangularis ( Veron & Pichon, 1980: 223, figs 375–384); holotype: NHMUK 1983.9 .27.2 (dry specimen; Fig. 20 ); type locality: Bushy Island−Redbill Reef , Australia, 5 m depth; phylogenetic data: none .

Taxonomic remarks

Paraclavarina Veron, 1985: 179 , was established as a monotypic genus with close affinity to Merulina . Its sole member was initially described as Clavarina triangularis Veron & Pichon, 1980: 223 , for its similarity to Merulina scabricula , effectively resurrecting Clavarina Verrill, 1864: 56 , for these two species ( Merulina scabricula being the type), where Chevalier, 1975: 208, had previously synonymized it. Studying specimens from Phuket and the Mergui Archipelago, Veron (1985: 181) deemed Clavarina triangularis Veron & Pichon to be distinct from Merulina ampliata and Merulina scabricula , which were more similar to each other instead. No details on these new observations were offered. Clavarina effectively became synonymized as Merulina once again, and Clavarina triangularis was transferred into Paraclavarina .

It should be noted that two of the three syntypes of Merulina scabricula (USNM 165 and YPM IZ 1927A; see species included for Merulina ) are ramose like Clavarina triangularis . Umbgrove (1940: 285) argued that Dana (1846: 275) based his description of this species only on part of a large colony that may have thin lamina at its base like Merulina ampliata . Evidently, neither he nor Veron (1985: 181), who referred to USNM 165 incorrectly as the holotype, saw the final syntype (YPM IZ 1927B), indeed a fragment of lamina. If this is indeed the pattern observed by Veron (1985: 181), then distinguishing the fully ramose Clavarina triangularis from Merulina , and by extension the establishment of Paraclavarina may be justified.

Evidently, the validity of Paraclavarina depends critically on its specific relationships with Merulina ampliata and Merulina scabricula . To date, Paraclavarina triangularis has never been collected for a phylogenetic study, and only three samples of each Merulina species have been analysed ( Romano & Palumbi, 1996; Chen et al., 2002; Fukami et al., 2008; Huang et al., 2011).

Paraclavarina is known only from the Central Indo- Pacific region bounded by the Makassar Strait, Palau, Papua New Guinea, Vanuatu, and the Great Barrier Reef in Australia.

Morphological remarks

The holotype of Paraclavarina triangularis has been examined and found to share all analysed macromorphological features with Merulina . It is however fully branching, lacking the encrusting and/ or laminar base found in Merulina .

GENUS PARAMONTASTRAEA HUANG & BUDD

Figures

Figure 20. Paraclavarina Veron, 1985: 179, is ramose and has uniserial corallites with few centres, fused walls, small (<4 mm) and low-relief (<3 mm) calices, septa in <three cycles (<24 septa), compact columellae, well-developed paliform (uniaxial) lobes, and no epitheca. A, B, Paraclavarina triangularis (Veron & Pichon, 1980), the type and only living species of Paraclavarina; macromorphology, holotype NHMUK 1983.9.27.2, Bushy Island-Redbill Reef, Australia.