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Paraclavarina

Veron, 1985, p. 179

Paraclavarina Veron, 1985, p. 179 is a junior synonym (available and invalid), see Merulina Ehrenberg, 1834, p. 328.

Type Species

Clavarina triangularis Veron and Pichon, 1980, p. 223, figs 375–384; Original Designation Veron, 1985, p. 179

Type Specimen: Holotype; NHMUK 1983.9.27.2; Verified; Dry Preserved

Type Locality: Bushy Island-Redbill Reef, Australia (Recent)

Classification

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 < 3 cycles (< 24 septa). Free septa present but irregular. Septa spaced 6–11 septa per 5 mm. Costosepta equal in relative thickness. Columellae trabecular but compact (1–3 threads), < 1/4 of calice width, and continuous among adjacent corallites. Paliform (uniaxial) lobes well developed. Epitheca absent and endothelia sparse.

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 and 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 three-pointed 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 and Pichon, 1980: 225)' (Veron, 1985: 179–180)

Comparisons

The holotype of Paraclavarina triangularis has been examined and found to share all analyzed macromorphological features with Merulina. It is however fully branching, lacking the encrusting and/or laminar base found in Merulina (Huang et al., 2014).

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 and Pichon, 1980: 223 for its similarity to Merulina scabricula, effectively resurrecting Clavarina Verrill, 1864: 56 for these two species (M. scabricula being the type), where Chevalier, 1975: 208 had previously synonymized it. Studying specimens from Phuket and the Mergui Archipelago, Veron, 1985: 181 deemed C. triangularis Veron and Pichon to be distinct from Merulina ampliata and M. 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 C. triangularis was transferred into Paraclavarina. It should be noted that two of the three syntypes of M. scabricula (USNM 165 and YPM IZ 1927A; see species included for Merulina) are ramose like C. 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 M. 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 C. 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 M. ampliata and M. scabricula. To date, P. triangularis has never been collected for a phylogenetic study, while only three samples of each Merulina species have been analyzed (Romano and Palumbi, 1996; Chen et al., 2002; Fukami et al., 2008; Huang et al., 2011).

Distribution

  • Western Pacific; Recent
  • Central Pacific; Recent
Source: Veron (2000). Distribution compiled by Matthew Tibbits. Recent: 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.

This page has been in preparation since 20-Jul-2010 15:12

This version was contributed by Danwei Huang on 08-Jun-2014 02:14.

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


holotype of Clavarina triangularis Veron and Pichon
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holotype of Clavarina triangularis Veron and Pichon
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