MCCOSKER:, GIGANTIC WORM EEL 
337 
condition, and posterior nostril location above the lip edge are similar in appearance to that of many 
deepwater congrids. Indeed, the holotype of the new species is remarkable in that it is nearly twice 
as long as and three times heavier than any known myi'ophine specimen. The second largest known 
specimen is the holotype of its conspecific, Pylorobranchus hoi, which is 676 mm in total length 
and 176 g in wet weight. Most myrophines reach no more than 450 mm TL and many are mature 
at 100 mm TL or less (McCosker unpublished data). 
The discovery of this, the second species of Pylorobranchus, requires a minor revision of a 
generic character unique to P hoi. The general osteology of the two species does not differ (as 
viewed from radiographs). The condition of their gill arches, which were removed and cleared-and- 
stained, is nearly identical; the first ceratobranchial of P hearstorum is cartilaginous whereas that 
of P hoi appears to be slightly ossified. Such differences exist within species of other ophichthids 
(Nelson 1966; McCosker 1977). The degree of median fin elevation, pectoral fm shape and size, 
body elongation and lateral compression, jaw condition, dentition, posterior nostril condition, and 
cephalic pore number and location are shared by both. The size and location of the gill opening 
(McCosker et al. 2013) oi P. hoi (“at lateral midline, reduced, a small opening smaller than eye 
diameter, preceded anteromedially by a small lappet-like fleshy protuberance”), does not differ; 
however, the fleshy protuberance is absent in P. hearstorum. 
The new species is sepai'able from Pylorobranchus hoi by several meristic and morphometric 
conditions. It has more vertebrae {P. hearstorum 226 vs. P hoi 182-183) more lateral-line pores 
{P. hearstorum ~210 vs. P. hoi 135), a longer tail {P. hearstorum 66% of TL vs. P. hoi 52-59%), a 
shorter head {P hearstorum 8.8% of TL vs, P hoi 11.0-11.8%), a more posterior dorsal-fin origin 
{P. hearstorum ahead of mid-tmnk vs. P. hoi behind mid-trunk), a more slender body and tail 
{P. hearstorum greatest depth 39 times in TL vs. P. hoi 29-31 times), shorter anterior nostrils, and 
it is darker in coloration {P hearstonim is uniform brownish black vs. P. hoi, which is uniform 
brown, head and trunk gray ventrally). It is unlikely that the new species would be mistaken for 
any other known myrophine (see the “Key to the Genera of Myrophinae” in McCosker et al. 2013), 
many of which lack pectoral fins and nearly all of which have their posterior nostril within their 
upper lip and opening into the mouth. 
The holotype is a female with minute undeveloped ova. Based on its dentition and jaw condi¬ 
tion it is likely that Pylorobranchus hearstorum, like P. hoi, feeds upon crustaceans and small fish¬ 
es. Other fishes collected by deep water traps and by trawls during the Academy Expedition in the 
Verde Island Passage are listed and explained by Iwamoto et al. (this volume). 
Comparative material examined. — Pylorobranchus hoi: TOU-AE 5574, 676 mm TL, 
holotype; TOU-AE 5525, 568 mm TL, and CAS 233704, 657 mm TL, paratypes 
Acknowledgments 
I wish to thank: David Catania (CAS) for the use of his photographs and assistance in the field; 
Corlis Schneider for preparing figures 3-4; Mysi Hoang (CAS) for preparing figures 1-2 and for 
staining and clearing the gill arches of the holotype; Terence Gosliner (CAS) for his leadership of 
the Hearst Expedition; the crew of the MA^ DA-BFAR; the staffs of the California Academy of Sci¬ 
ences (CAS), Hsuan-Ching Ho of the Institute of Marine Biodiversity and Evolutionary Biology, 
Checheng, Taiwan, and the staff of the fish division. National Museum of Natural History 
(USNM), Washington D. C., for advice and assistance with specimens; and Tomio Iwamoto (CAS) 
and David Smith (USNM) for reading a draft of this manuscript. And finally, I sincerely thank Mar¬ 
garet and Will Hearst for their generous support of the Academy expedition to the Philippines. 
