Yongjiacaris

Yongjiacaris is an extinct genus of shrimp, which had only one species, Yongjiacaris zhejiangensis.[1] Yongjiacaris represents the second report of freshwater caridean shrimp from the Mesozoic.[1]

Yongjiacaris Temporal range: Barremian PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Decapoda
Infraorder:	Caridea
Family:	Palaemonidae
Genus:	Yongjiacaris Garassino, Shen, Schram & Taylor, 2002
Species:	Y. zhejiangensis
Binomial name
Yongjiacaris zhejiangensis Garassino, Shen, Schram & Taylor, 2002

The name of the genus Yongjiacaris refers to Yongjia County, in the Zhejiang Province of China, while the species name Y. zhejiangensis is derived from the province name.[1] Yonjiacaris was formally described by Alessandro Garassino, Shen Yanbin, Frederick R. Schram, and Rod S. Taylor in 2002.[1] It is described from 138 specimens discovered in the C Member of the Moshishan Formation of Yongjia County, and from specimens found in the Showchang Formation near Jiande, both in southeastern China.[1] These two correlative rock units date to the Barremian age of the Early Cretaceous; volcanic rocks in the C Member of the Moshishan Formation are dated to 120 million years old, and volcanic rocks in the Showchang Formation are dated to 118 million years ago.[1] The C Member of the Moshishan Formation is a heterogeneous rock unit including sandstone, shale, tuff, conglomerate, and rhyolite, while the Showchang Formation is dominantly sandstone and mudstone.[1] The types of plants present in the C Member and the Showchang Formation (relatively abundant ferns and Bennettitales, rare members of the Ginkgoaceae) and characteristics of the plants, such as leaf form and cuticle thickness, indicate a relatively hot and dry climate.[1] The two rock units have fossil assemblages including plants, charophytes, bivalves, ostracods, conchostracans, and insects.[1]

While other genera from the family Palaemonidae are known from the Aptian age in the lower Cretaceous period, Yongjiacaris represents the first member described from the Barremian age.[1] It measured from 1.5 to 2 centimetres (0.6 to 0.8 in) in length.[1]

References

1. Alessandro Garassino, Shen Yanbin, Frederick Schram & Rod S. Taylor. (2002). "Yongjicaris zhejiangensis n. gen. n. sp. (Crustacea, Decapoda, Caridea) from the Lower Cretaceous of Zhejiang Province, China'" (PDF). Bulletin of the Mizunami Fossil Museum. 29: 73–80.CS1 maint: multiple names: authors list (link)