A revised chitinozoan classification

Abstract

The successful definition of chitinozoan genera depends primarily on the precision of the criteria used. A standardized morphological terminology based upon details from scanning electron microscope observations of the most representative taxa bearing these characters is therefore proposed. The 143 genera, or subgenera, described so far in the literature are reviewed in order to exclude invalid taxa and obvious junior synonyms. Particular attention is paid to preventing the overlap of generic definitions of the 56 genera ultimately retained. A brief account of the diagnostic features and stratigraphic range of selected genera is given, and basic information concerning the type material of these genera is listed. Finally, a suprageneric classification of the whole Chitinozoa group based on diagnostic features whose hierarchy is established on statistical and evolutionary grounds, is given. One new subfamily, Pogonochitininae, three new genera, Baltochitina, Hyalochitina, and Saharochitina, and a new species Baltochitina nolvaki, are defined. The subspecies Fungochitina fungiformis spinifera is elevated to a specific rank.

Dapingian-lower Darriwilian (Ordovician) stratigraphic gap in the Faraghan Mountains, Zagros Ranges, south-eastern Iran

“…The classification system of Paris et al (1999) is used. The following symbols are adopted for systematic and biometric descriptions: L = total length of vesicle; 1 = length of chamber; ln = length of neck with collarette; D = maximum diameter of vesicle; dcoll = diameter of collarette; ls = length of spines; L/D = total length of vesicle/maximum vesicle diameter; and L/ln = total vesicle length/length of neck; (x) = mean; N = number of specimens; (max) = maximum observed size; (min) = minimum observed size.…”

A chitinozoan morphological lineage and its importance in Lower Silurian stratigraphy

“…They bring into question the systematic status of the two genera, although to avoid confusion both are presently retained. They also have implications for other morphologically similar chitinozoan taxa and for the cladogram of Paris et al (1999, fig. 10).…”

“…67) showed that the genus Margachitina was derived from Linochitina Eisenack and also illustrated small scale phylogenies in species of Ordovician-Devonian Chitinozoa (Paris 1981, figs 62-64). Multivariate statistics and cladistic analysis have recently been used to group morphologically similar chitinozoan taxa together (Paris et al 1999). Factoral analysis of correspondence shows that there is a close morphological similarity between Margachitina and Calpichitina (Paris et al 1999, figs 6-7).…”

“…4). M. margaritana has broad morphological similarities with Calpichitina densa (Eisenack, 1962): they are alike in size and in their tendency to form chains; however, in M. margaritana, a peduncle (sensu Paris et al 1999) separates adjoined vesicles. …”

Chitinozoan biostratigraphy of the Upper Ordovician of Faulx-les-Tombes (central Condroz Inlier, Belgium)

“…Discussion: the specimens described herein are shorter than Spinachitina cervicornis (Eisenack, 1931), of which the holotype is 240μm long. The proposed neotype (Paris et al, 1999), however, has a length of 140μm. The spines of our specimens differ from those of S. cervicornis (Eisenack, 1931): the latter species always has simple spines, whereas our specimens' spines are sometimes multi-rooted and can have a granular ornamentation.…”