565
X
Xenacoelomorpha, 248
Xenidae, 423
Xenomas, 71
fossil record, 75
morphology and distribution, 75
Xenoparasitic complexes, 71
See also Xenomas
Xiphosura, 315, 321
as hosts for
epibionts, 337
parasites, 337
feeding ecology, 322
Xyelidae, 478, 480
Xyeloidea, 478, 480
Xyelotomidae, 480
Xyelydidae, 480
Y
Yanliao Biota, 481
taphonomy, 482
See also Jiulongshan Formation
Yersinia pestis, 45
Yixian Formation, 481
age, 481
Ypresian, 244
Z
Zygaenoidea, 428, 486
Zygopleuridae, 225
fossil record, 225
Index