Merulina
Ehrenberg, 1834, p. 328
Type Species
Madrepora ampliata Ellis and Solander, 1786, p. 157, pl. 41, fig. 1,2; Original Designation Ehrenberg, 1834, p. 328
Type Specimen: Holotype; GLAHM 104015; Verified; Dry Preserved
Type Locality: 'les mers de l'Inde' (Lamarck, 1816, p. 243) (Recent)
Classification
Synonyms
Diagnosis
Colonial, with intracalicular budding only. Corallites monomorphic and uniserial; 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 endotheca sparse. Tooth base at mid-calice circular. Tooth tip at mid-calice irregular; tip orientation perpendicular to septum. Tooth height low (< 0.3 mm) and tooth spacing narrow (< 0.3 mm), with > 6 teeth per septum. Granules scattered on septal face; irregular in shape. Interarea palisade. Walls formed by strong abortive septa and partial septotheca; trabeculothecal elements may be present. Thickening deposits fibrous. Costa center clusters weak; < 0.3 mm between clusters; medial lines weak. Septum center clusters weak; < 0.3 mm between clusters; medial lines weak. Transverse crosses absent. Columella centers clustered.
Description
'Fere pedalis, frondibus liberis, subflabellatis, e ramulis coalitis dichotome colliculatis, collibus lamelloso-serratis, asperrimis, vix lineam altis, stellis in seriebus dichotomis saepe confluentibus positis, sulcis lineam latis, parietibus turgidis, 2''' distantibus.' (Ehrenberg, 1834: 328)
Comparisons
Only one synapomorphy has been found for Merulina: septa in < 3 cycles (< 24 septa). It shares all other analyzed characters with Scapophyllia. The loss of epitheca and sparse endotheca occur at the base of the Merulina + Scapophyllia clade on the morphology tree, and all subcorallite character transitions occur at or before the most recent common ancestor of Merulina, Scapophyllia and Goniastrea. They are therefore plesiomorphic with respect to Merulina. Examination of the type material of Merulina scheeri at the Natural History Museum, London, suggests that this species shares all macromorphological characters with the other species in the genus, except for a thick thecal structure on the underside of the corallum. While the number of septa often exceeds 24, they clearly form two alternating cycles and the lower range is under 24. With its molecular phylogenetic affinity unknown, we hereby preserve its generic placement.
Remarks
The genus was first described as part of the family Daedalina Ehrenberg 1834: 315, and subsequently Astraeidae Dana, 1846: 154, which incorporated a diversity of genera including Lobophyllia de Blainville, 1830: 321, Favia Milne Edwards and Haime, 1857, vol. 2: 426, and Mycedium Milne Edwards and Haime, 1851, vol. 15: 130. The designation of Merulina as the type of Merulinidae Verrill, 1865, was unclear since the family name was only listed and not defined (Verrill, 1865: 146), but this had thereafter been assumed. Even as Daedalina's constituent genera were redistributed into newly-erected families such as Mussidae Ortmann, 1890: 315, Faviidae Gregory, 1900: 29, Trachyphylliidae Verrill, 1901: 84, and Pectiniidae Vaughan and Wells, 1943: 196, the placement of Merulina remained ambiguous according to some authors (Vaughan, 1918; Hoffmeister, 1925), while Hickson (1924), Faustino (1927) and Matthai (1928) continued to recognize Dana's (1846) Astraeidae. The separation of Merulina from Faviidae Gregory, 1900, was only complete in the comprehensive treatise by Vaughan and Wells (1943). Molecular data supports Merulina as nested within the largest clade of Goniastrea but the latter is not monophyletic as it minimally excludes G. aspera and G. palauensis (Fukami et al., 2004, 2008; Kitahara et al., 2010; Huang et al., 2011; Huang 2012; Arrigoni et al., 2012). In contrast, the morphological tree supports Merulina as sister taxon to Scapophyllia, which together are sister group to the main clade of Goniastrea that includes G. retiformis, its type species.
Distribution
- Southeast Asia; Miocene
- Melanesia; Pliocene
- Southeast Asia; Pliocene
- Subsaharan Africa; Pleistocene
- East Asia; Pleistocene
- Indian Ocean; Recent
- Western Pacific; Recent
- Central Pacific; Recent
Historical distribution: Recent., Indopacific (Wells, 1956). Source: Paleobiology database (accessed 6/4/12), Veron (2000). Distribution compiled by Matthew Tibbits. Recent: Merulina is widely distributed on reefs of the Indo-Pacific, present as far east as the Austral Islands in the southern hemisphere (Glynn et al., 2007), but absent eastwards from Hawai'i in the north.This page has been in preparation since 20-Jul-2010 02:55
This version was contributed by Danwei Huang on 05-Feb-2014 19:25.
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
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