Corresponding author: Bert W. Hoeksema (
Academic editor: L.P. van Ofwegen
The recent taxonomic history of extant free-living
Mushroom corals (
The smallest species among free-living mushroom corals appear to be among the most difficult to identify because they show relatively few distinguishing characters and much ecophenotypic variation (
Previously, species of the
Oddly, both
The two specimens (ZMA Coel. collection) earlier described by
Lectotype of
Paralectotype of
All species of the former
= B.W. Hoeksema = Expedition = Island = Station = Museum of Tropical Queensland, Townsville, Australia = Rijksmuseum van Natuurlijke Historie, Coelenterate collection (Naturalis Biodiversity Center), Leiden, the Netherlands = Zoological Museum – University of Copenhagen, Denmark = Zoological Museum of Amsterdam Coelenterate collection (Naturalis Biodiversity Center), Leiden, the Netherlands
Adult corals either encrusting and polystomatous or free-living and monostomatous (
Type specimens of
Holotype of
(
Specimen of
Specimen of
Specimen of
Specimen of
Specimens of
Two specimens of
Two specimens of
Juvenile, attached specimens of
(
Map of the Central Indo-Pacific indicating localities where
The species is named after the late Prof. Hilbrand Boschma, former director of the Rijksmuseum van Natuurlijke Historie (now Naturalis Biodiversity Center), who devoted much of his research time to the study of mushroom corals, including specimens of the new species.
Adult corals small (< 50 mm) with uneven circular corallum margin owing to enlarged costae. Live specimens with variable, patchy colouration.
1a | Lower order costae distinctly larger than other ones | 2 |
1b | Costae fine, adjacent ones equal to almost equal | 5 |
2a | Coralla flat and thin, corallum outline circular | 3 |
2b | Coralla thick and slightly arched, corallum outline slightly or much oval | 4 |
3a | Lower order costae thicker and longer than higher order costae, ornamentation fine (20–70 / cm), maximum corallum diameter 5 cm, habitat mostly consisting of reef slopes and sandy reef bases | |
3b | Lower order costae sharp, ornamentation very fine (40–80 / cm) on lower order costae and indistinct on higher order costae, maximum corallum diameter 8 cm, habitat mostly consisting of deep, sandy reef bases |
|
4a | Corallum outline slightly oval, lower order costae irregularly and roughly ornamented (20–70 / cm), maximum corallum diameter 8.5 cm, habitat consisting of upper reef slopes |
|
4b | Corallum outline clearly oval, lower order costae sharp, costal ornamentation very fine (40–90 / cm) and nearly absent on higher order costae, maximum corallum diameter 12.5 cm, habitat mostly consisting of deep, sandy reef bases |
|
5a | Septa densely packed and (almost) equal in height | 6 |
5b | Septa loosely packed, septa of lower orders thicker and more exsert than others | 7 |
6a | Central fossa short (< 10% of corallum diameter); all septa perforated, nearly equal in size and tightly packed with little space in between them, maximum corallum diameter 8.5 cm, habitat mostly consisting of deep, sandy reef bases |
|
6b | Length of central fossa > 10% of corallum diameter, septa of lower order solid and thicker than adjacent septa with distinct space in between them, maximum corallum diameter 7.5 cm, habitat consisting of deeper reef slopes or reef bases |
|
7a | Corallum outline oval | 8 |
7b | Corallum outline circular or irregularly round with folds or undulations | 9 |
8a | Coralla thick; underside flat or arched, costae equal, maximum corallum diameter 9 cm, habitat consisting of lower reef slopes or sandy reef bases |
|
8b | Coralla convex around fossa (humped), costae equal in juveniles, maximum corallum diameter 12.5 cm, habitat mostly consisting of deep, sandy reef bases |
|
9a | Coralla with folded, undulating margin | 10 |
9b | Coralla with regular, smooth periphery | 11 |
10a | Coralla thin, central fossa short (< 10% of corallum diameter), margin undulating (hexagonal in juveniles) maximum corallum diameter 8.5 cm, habitat consisting of sandy reef slopes or sandy reef bases |
|
10b | Coralla thick and usually strongly arched, margin with folds, maximum corallum diameter 8.5 cm, habitat consisting of lower reef slopes or sandy reef bases |
|
11a | Coralla and septa thin, adjacent costae slightly alternating in size maximum corallum diameter 15 cm, habitat mostly consisting of sandy reef bases |
|
11b | Coralla moderately thick, lower order septa thicker than others, costae nearly similar in size, maximum corallum diameter 12 cm, habitat consisting of lower reef slopes or sandy reef bases |
|
Although some material of
The
With the inclusion of
Because
Small-sized free-living mushroom corals have been reported to show much mobility (
Although free-living
I am grateful to the following people, organizations and institutes who assisted during the fieldwork or other parts of the research: Dr. Alfian Noor and Drs Willem Moka (Universitas Hasanuddin, Makassar), Dr. Carden C. Wallace (MTQ, Tethyana Expedition to the Togian Islands), Dr. Filipina B. Sotto and Dr Thomas Heeger (University of San Carlos, Cebu City), Dr Jacob van der Land (Naturalis, Snellius-II Expedition), Dr. Pat Colin and Ms Lori Colin (Coral Reef Research Foundation, Palau), Dr. Phillipa Mansell (Operation Wallacea, Wakatobi, Indonesia), Dr. Jos Pet (The Nature Conservancy, Bali), Dr Suharsono (Research Centre for Oceanography, Indonesian Institute of Sciences, Jakarta), Ms. Zarinah Waheed (Borneo Marine Research Institute, Kota Kinabalu). The research was partly financed by the Netherlands Foundation for the Advancement of Tropical Research (WOTRO, grant W77-96) and by the Schure-Beijerinck-Popping Fonds. I thank Ms. Majken T. Tøttrup and Dr. M.V. Sørensen for the loan of specimens from the UZMK. I thank Dr Carden C. Wallace and Mrs. Barbara Done for the loan of specimens from the MTQ. I am grateful to Mrs. Elly Beglinger and Mr. Koos van Egmond for their help in accessing ZMA and RMNH specimens. Comments given by two anonymous reviewers helped considerably to improve the text.