''Sagavia'' is a genus of
trilobite
Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the At ...
s that lived during the
Middle and Upper Ordovician in what are now Northwest and Southeast China, North Kazakhstan and Wales. It is a typical
cyclopygid that can be distinguished by its large but separate eyes, elongated glabella, five thorax segments and a pygidium with clearly defined axis and border.
Species and distribution
* ''S. chuanxiensis''
(Li & Xiao, 1984) (
synonym
A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...
''Microparia (Microparia) chuanxiensis'') is found in the Middle and Upper Ordovician of China (late Caradoc-Ashgill, top of the Pagoda Formation, limestone block in a Triassic melange accumulation at Shiqu; Yuanba, Hougou and Liangshan, Nanzheng; Dangmengou and Zhuyegou, Ningqiang; Qishuba and Gaoqiaogou, Mianxian; all Northwestern Sichuan).
* ''S. elongata''
Petrunina, 1975 is present in the Upper Ordovician of China (?Ashgill, ''Kielanella''-''Tretaspis'' Beds of the Ulugtay District, south Tien Shan).
* ''S. felix''
Koroleva, 1967 ( type) has been collected from the Middle Ordovician of Kazakhstan (Caradoc, ''Nemagraptus gracilis'' Zone, Saga Formation, Saga River section, Stepnyak district).
* ''S. glans''
Fortey & Owens, 1987 was excavated from the Upper Ordovician of the United Kingdom (late Arenig, Pontyfenni Formation, South Wales).
* ''S. heterocyclopygeformis''
Koroleva, 1982 is known from the Middle Ordovician of northern Kazakhstan (Caradoc).
* ''S. modica''
Koroleva, 1967 is known from the Middle Ordovician of Kazakhstan (Caradoc, ''Nemagraptus gracilis'' Zone, Saga Formation, Saga River section, Stepnyak district).
* ''S. novakellaformis''
Koroleva, 1982 occurs at the Koroleva from the Middle Ordovician of northern Kazakhstan (late Llanvirn?), and the United Kingdom (''Hustedograptus teretiusculus'' Biozone of the Llanfawn Mudstone Formation, central Wales).
* ''S. zhuyegouensis''
Koroleva, 1982 occurs at the Middle Ordovician of China (late Caradoc, Dangmengou, Ningqiang Northwestern Sichuan).
Description
The glabella of ''Sagavia'' is elongate with parallel sides or slightly converging towards the front. The large eyes are separated at the front by the glabella and the cephalic doublure. The
rostral suture is vaulted upwards. It has a thorax of five segments. ''Sagavia'' has a pygidium with well a defined axis and border with clear furrows.
Differences with related genera
* ''Sagavia'' is similar to ''Microparia'' but has a more elongate glabella and much better defined pygidial axis and border.
* ''Heterocyclopyge'' also has a defined pygidial axis, a five-segmented thorax, and a defined pygidial border, but has a shorter glabella and the pygidial border and axis are poorly defined medially.
References
Cyclopygidae
Asaphida genera
Ordovician trilobites
Fossils of China
Fossils of Kazakhstan
Fossils of Great Britain
Middle Ordovician first appearances
Late Ordovician extinctions
{{Asaphida-stub