A New Platy-armored Worm from the Early Cambrian Chengjiang Lagerstatte,South China

The Lower Cambrian Chengjiang Lagerstatte provides a good window to explorethe origin and radiation of early bilaterians. Here we describe a netted sclerite-bearing wormTabelliscolex hexagonus gen. et sp. nov., and tentatively assign it to palaeoscolecidans ofpriapulids. The cuticle of the animal is covered with two kinds of platy sclerites which areconstructed by hexagonally arranged tubercles Similar structures of the sclerites can be seen onsome Cambrian palaeoscolecidans and lobopods, so, this new species is critical for understanding therelationships between lobopods and palaeoscolecidans.

Addressing the Chengjiang conundrum: A palaeoecological view on the rarity of hurdiid radiodonts in this most diverse early Cambrian Lagerstatte

Over one hundred arthropod fossil species have been described from the famous Chengjiang Lagerst?tte(South China, Cambrian Stage 3, ca. 518 Ma) including a diverse assemblage of radiodonts–a group containing Anomalocaris and its relatives. These iconic stem-group euarthropods include some of the largest animals of the time, and some are known from hundreds of specimens. A longstanding conundrum has been the rarity or absence of hurdiids from Cambrian Series 2 Lagerst?tten like Chengjiang. This is because radiodonts are generally common in such deposits and the oldest radiodont ever discovered is a hurdiid. Furthermore, this family displays the widest geographic and temporal ranges of all radiodont families, and the highest diversity. Here we document the first hurdiid frontal appendages from Chengjiang, which display unique features within the family and may provide insights for understanding the character evolution of hurdiid appendages. The palaeoenvironmental distribution of hurdiids suggests that the rarity of hurdiids in Chengjiang may be due to a preference for deeper water environments,and the later success of this family from the Wuliuan onwards may relate to their ability to tolerate cooler water temperatures than other radiodont families. The palaeogeographical, palaeoenvironmental, and stratigraphical patterns observed in hurdiids maybe caused in part by the limited distributions of Konservat-Lagerst?tten in the Cambrian as well.

The earliest-known ancestors of Recent Priapulomorpha from the Early Cambrian Chengjiang Lagerstatte

The taxonomy of an early ancestor of Recent Priapulidae, Xiaoheiqingella peculiaris (= Yunnanpriapulus halteroformis Huang et al., 2004) from the Early Cambrian Chengjiang fossil Lagerst?tte, is revised. Morphological characters comprise a pair of caudal appendages rather than a single appendage flanking the trunk end and a possible urogenital duct found inside the preanal region. An addi- tional extremely rare fossil priapulid worm, Paratubiluchus bicaudatus gen. nov., sp. nov. is also described herein. Its diagnostic characters are: an introvert bearing 25 longitudi- nal rows of scalids, a distinct neck region, no annulus on the oval trunk, and a pair of caudal appendages. The proportion of body parts is similar in size to that of loricate larvae of Recent priapulids and larva-formed Palaeopriapulitidae. Taking account of the features of Xiaoheiqingella, bicaudal appendages are considered to be a synapomorphy of Pri- apulidae and Tubiluchidae. Paratubiluchus gen. nov. is most likely a candidate for the ancestor of the Tubiluchidae; it probably originated from a larva-formed priapulid with 25 rows of scalids, thus representing an intermediate link be- tween the priapulids in mature-form and the priapulids with lorica.

Pediculate Brachiopod Diandongia pista from the Lower Cambrian of South China

The Chengjiang Lagerstatte has been celebrated for prolific soft-bodied fossils. Based on specimens recently excavated in the Chengjiang Lagerstatte by the Early Life Institute, Northwest University, Diandongia pista Rong, 1974, is directly revealed to be a pediculate brachiopod, assigned to the Family Botsfordiidae, as is further confirmed by the exceptionally preserved vascular system including dorsal and ventral mantle canals. These specimens described herein exhibit some peculiarities, notably the extremely thin and long pedicles, which suggest that Diandongia is epifaunal rather than burrowing brachiopod. A study of this group of animals indicates that they may be vital to understand the relationship between the lingulids and the remaining brachiopods, and the character evolution of the early Cambrian brachiopods.

Two new spider families from Late Cretaceous Kachin amber(Arachnida: Araneae)

Two new spider families from Late Cretaceous Kachin amber(Myanmar),Pilosarachnidae Jiang&Li,fam.nov.and Gigarachnidae Jiang&Li,fam.nov.,are described:Pilosarachne ju Jiang&Li,gen.&sp.nov.and Gigarachne bian Jiang&Li,gen.&sp.nov.Type specimens are deposited in the Institute of Zoology,Chinese Academy of Sciences in Beijing(IZCAS).Both families bear three tarsal claws and are most likely entelegyne.Diagnostic characters of extinct families in Kachin amber with uncertain relationships with extant fauna are listed and discussed.