220 
THE CORAL TRIANGLE: HEARST BIODIVERSITY EXPEDITION 
VIP is the “center of the center” {sensu Carpenter and Springer 2005) of diversity in the Coral Tri¬ 
angle in terms of echinoids, and that diversity is high at all depths. 
A major contribution of the Expedition was the discovery of five taxa never before seen in the 
Philippines, and a sixth {Stomopneustes variolaris) suspected to occur there, but not hitherto veri¬ 
fied in published records. Although none of these is new to science, they reinforce the inference 
that the VIP is among the most diverse regions of the world’s oceans. Many other taxa remain to 
be discovered even within a group of echinoderms in which a year or more can go by without the 
discoveiy of new extant species. For example, at least six species of Philippine Irregularia alone 
(van Noordenburg 2008) are suspected to be new to science (although not all of them have been 
found in the VIP as yet). 
Another significant find during the shallow-water component of the expedition includes the 
most westerly occuiTence of the “hair-spined urchin”, Lissodiadema lorioli (Fig. 4A). The phylo¬ 
genetic systematics of this poorly-known, relatively rare diadematid remain equivocal because of 
a lack of analysis, potential synonymy with the Hawaiian species Leptodiadema purpureum, and 
poor quality of the type material of both taxa. However, it is clear that Lissodiadema ranges wide¬ 
ly throughout the Pacific and is being more frequently seen by divers interested in cryptic species 
with cavemicolous tendencies. The spines of this urchin are striking, being as fine or finer than a 
human hair — so thin that they can be bent easily en masse in the living animal (Fig. 4B). 
During the trawling by the MA^ “DA-BFAR”, several minute spechnens of “wood urchins” 
representing two species in the genus Prionechinus were discovered (Figs. 4C, D). Neither of these 
species were previously known to occur in the Philippines. Wood urchins are members of a poor¬ 
ly known family of camarodonts currently known as the Trigonocidaridae. As noted by Mortensen 
(1943a), several species of trigonocidarids are known to be xylophagous, and are found exclusive¬ 
ly on sunken wood derived from deciduous trees (i.e. not on coconut or other palm tree fragments). 
Trigonocidarids species are known to harbor gut flora capable of digesting cellulose (Becker et al. 
2009). Wood-falls are sometimes regarded as “stepping stone” habitats representing alternative 
energy sources for deep-sea taxa that have evolved to exploit whale-falls and deep-sea thermal 
vents (Kiel and Goedert 2006). The study of echinoids that can live exclusively on wood will lead 
to many lines of inquiry ranging from the phylogenetic origins and diversification of trigonoci¬ 
darids to the ecological significance of forest-derived outfall in deep ocean adjacent to the Philip¬ 
pines coast, where some of the steepest and deepest drop-offs in the Indo-Pacific can be found. 
Trawling work also recovered several specimens of very large heart urchins. Each of these 
specimens in turn yielded other parts of deep-sea biodiversity because of the fact that they bore 
commensals from widely disparate taxonomic groups. For example, one specknen of Plesiozonus 
hirsutus was home to what appear to be two different species of brittlestar (Fig. 4E), and a bivalve 
mollusk living just inside the test in the anal region (A. Kroh, personal communication). Other 
trawling events of the Expedition resulted in several specimens of Chaetodiadema granulaturn. 
Although most of these were damaged, the tissues were sufficiently undisturbed to reveal the 
remarkable structural colors caused by isolated spots of iridophores amanged in rows in the aboral 
interambulacra (Fig. 4F). This phenomenon was carefully described by Mortensen (T940a), but his 
black and white illustrations do not do justice to the nearly 100% reflectance of these spots. Irides¬ 
cent lines and spots in a variety of colors are commonly photographed in diadematids from shal¬ 
low water such as Diadema, Astropyga, and Echinothrix. Although de Meijere (1904) illustrated 
the spots in a color drawing of C gi'anulatum, to the best of our knowledge, Figure 4F is the first 
published color photo of these spots in a deep-sea echinoid. 
During work on the M/V “DA-BFAR”, it was discovered that Micropyga violacea (Fig. 5A) 
was one of only two echinoid species to enter commonly the baited fish traps (the other being the 
