A Gigantic Deepwater Worm Eel (Anguilliformes: Ophichthidae) 
from the Verde Island Passage, Philippine Archipelago 
John E. McCosker 
California Academy of Sciences, San Francisco, California 94118 
E-mail: Jmccosker@calacademy. org 
A new species of a deepwater ophichthid worm eel was collected from the Verde 
Island Passage of the Philippine Archipelago. Pylorobranchus hearstorum sp. nov., 
subfamily Myrophinae, is described and illustrated from a specimen trawled in 
892-966 m. It is much larger than any known myrophine and differs from its only 
congener, P. hoi, in its longer tail (66®/o of TL vs. 52-59yo), shorter head (8.8% of XL 
vs. 11.0-11.8®/o), body depth (39 times in TL vs. 29-31), dorsal-fm origin (ahead of 
mid-trunk vs. behind mid-trunk), vertebral number (226 vs. 182-183), and its col¬ 
oration (brownish black vs. uniform brown). The known ophichthid fauna of the 
Philippines is discussed and listed. 
Keywords: Ophichthidae; Pylorobranchus hearstorum sp. nov.; Verde Island Passage, 
Philippines 
The center of diversity of fishes in the Indo-Malay-Philippines archipelago is said to be in the 
Philippines (Carpenter and Springer 2005). The California Academy of Sciences recently mounted 
an expedition sponsored by William and Margaret Hearst to further investigate the diversity of 
plants and anunals at several Philippine localities. Shallow water collections were made using 
scuba and deepwater collections were made aboard the MN DA-BFAR in the vicinity of the Verde 
Island Passage, between Luzon and Mindoro islands. Preliminary findings have added several new 
marine fish species including a shallow water, coral reef-inhabiting snake eel, Myrichthys palera- 
cio, collected from southern Luzon Island and described by McCosker and Allen (2012), and a 
deepwater myrophine trawled from the Verde Island Passage. Other eels collected, including two 
deepwater morays, are currently under investigation and may represent either new species or slight¬ 
ly different of rare and poorly known muraenids. The collections, although not comprehensive con¬ 
sidering the diversity of habitats and the enomiity of space in the Philippines, do indicate that addi¬ 
tional unknown taxa remain to be discovered. 
The center of diversity of ophichthid eels in the Indo-Malay-Philippines archipelago has not 
been adequately analyzed such that a confident prediction of comparative insular biodiversity can 
be made. Unpublished studies by systematists at the California Academy of Sciences (this author), 
the National Museum of Natural History (David G. Smith), and Silliman University (Abner Bucol) 
have advanced us toward that goal. The Philippine snake eels and wonn eels of the family 
Ophichthidae were previously treated by Weber and de Beaufort (1916), Fowler (1918), Herre 
(1923), and subsequent authors including Allen and Erdmann (2012) and my published and unpub¬ 
lished works, resulting in a list comprising approximately 50 valid and six questionable species.^ 
Whereas the Philippine ichthyofauna comprises many opliichthids (Appendix 1), several of which 
{Muraenichthysphilippinensis, M. thompsoni, and Myrichthys paleracio) are known only from the 
archipelago, there are many species and genera known from Malaysia and Indonesia that have yet 
1 The type specimens of Muraenichthys rnalaboensis and Ophichthus manilensis, destroyed during WWII, have not 
been subsequently observed and probably are not valid species. 
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