MOOI & MUNGUIA: SEA URCHINS OF THE PHILIPPINES 
217 
1948b, 1950, 1951) laid the groundwork for our understanding of echinoid biodiversity, providing 
many of the best-documented records of species occurring in the Philippines. Mortensen’s work 
remains a primary source for other biogeo graphic and bathymetric data as well. Many of the echi¬ 
noid species he listed as occurring in the Philippines were collected during surveys conducted by 
the United States Fisheries Steamer “Albatross” between 1907 and 1910. The majority of this mate¬ 
rial is housed at the Smithsonian Institution in the National Museum of Natural History (NMNH). 
In its catalog, the NMNH has 139 of the species known to occur in the Philippines. This material 
is of particular significance because until the 21st century, it represented nearly all the sampling in 
the region done below depths of about 50 meters. For some species, the “Albatross” specimens are 
the only ones known. 
For these reasons alone, the 2011 Hears! Philippine Biodiversity Expedition was significant in 
shining new light on echinoids from deeper waters around the Philippines. The deep-sea compo¬ 
nent of the Expedition led to verific ation of many records, and provided additional data on bathym¬ 
etry. Specimens from the shallow water component clarified many aspects of the distribution of 
taxa down to scuba depths, and also revealed new records of some taxa within the Philippines. A 
total of 106 Phihppine echinoid species are cataloged into the Invertebrate Zoology collections of 
the California Academy of Sciences (CASIZ). Of these, 52 were identified from the collections 
made during the Hears! Expedition, and 65 are held in common in the CASIZ and NMNH collec¬ 
tions, constituting a combined total of 180 species represented by the collections of both institu¬ 
tions. In other words, 30 species are not known in either institution’s holdings, but were recorded 
in works such as Fell (1963), Lane et al. (2000) and van Noordenburg (2008). In two instances, 
Philippine species were identified from websites constmcted by private collectors. All these 
sources are noted in the table presented in the Appendix. The contents of the species list are sum¬ 
marized by higher taxon in Table 1. 
Significance of the Philippine echinoid fauna 
Our results indicate, as has been found in studies of other taxa in the Coral Triangle, that there 
are more echinoid species in the Philippines than in other comparable ecoregion in the world. For 
example, in comparing records compiled from sources such as Dollfus and Roman (1981), the 
Philippines is home to nearly four times as many species as occur in the entire Red Sea. Prelimi¬ 
nary estimates compiled from Mortensen’s Monograph and other sources suggest that only half the 
number of species seen in the Philippines have been recorded from India, Malaysia, and Indonesia 
combined. This is partially a reflection of the lack of detailed knowledge of the faunas of these 
regions. Inspection of collections at the California Academy of Sciences and the NMNH, along 
with counts made from Mortensen’s Monograph indicate that it is unlikely that future surveys of 
these regions will push species richness numbers beyond what is found in the Philippines. Accord¬ 
ing to estimates compiled from similar sources, there are more than twice as many echinoid species 
in the Philippines as in the Gulf of Mexico and Caribbean Sea together. 
Almost 130 species of Philippine echinoids occur at depths less than 100 meters, and just over 
80 of these can be encountered at depths of 10 meters or less. However, 11 are restricted to depths 
greater than 500 meters, and of these, 5 are restricted to depths greater than 1,000 meters. There¬ 
fore, the Philippine echinoid fauna is well represented not only in terms of taxonomy, but also in 
terms of bathymetry. 
Table 1 shows that among the major clades of echinoids, the group contributing the single 
highest number of species is the heart urchins (Spatangoida), with nearly 27% of the total. The 
cidaroids, camarodonts, and clypeasteroids contribute similar numbers of species, and combine to 
